Selected Abstracts

ARTICLE

Lecture and communication abstracts 

Clinical forms of magnesium depletion with hypofunction of the biological clock

Jean Durlach 

Society for the Development of Magnesium Research (SDRM), Neuilly/S, France 

Mg depletion is a type of Mg deficit due to a dysregulation of the Mg status. It cannot be corrected through a nutritional supplementation only, but requires the most specific correction of the dysregulating mechanism. Among those, biological clock dysrhythmias are to be considered. The aim of this study is to analyze the clinical forms of Mg depletion with hypofunction of the Biological Clock (hBC). hBC may be due to either Primary disorders of BC [Suprachiasmatic Nuclei (SCN) and pineal gland (PG)] or Secondary with homeostatic response [reactive Photophobia (Pj)] to light neurostimulating effects [Nervous Hyper Excitability (NHE)]. The symptomatology is mainly diurnal and observed during fair weather (Spring, Summer). 
The elective marker of hBC is represented by a decrease of melatonin and of its metabolites in various fluids. 
The clinical forms of NHE due to Mg depletion with hBC are central and peripheral. The central forms associate anxiety, headaches and dyssomnia. 
The peripheral manifestations are neuromuscular: photosensitive epilepsia mainly. Three chronopathological forms of Mg depletion with hBC have been highlighted: 1. Headaches with Pj: mainly migraine 2. Sudden Infant Death Syndrome (SIDS) 3. Multiple Sclerosis (MS). 
– Headaches with Pj, migraine particularly. These cephalalgias are diurnal with Pj and are aggravated during the fair seasons (particularly during midnight sun -summer). Migraine is their typical form with its dishabituation to visual stimuli and its occipital cortex hyperexcitability. Comorbidity with anxiety is frequent. In 2/3 of the cases, it appears first. 
– SIDS might be linked to an impaired maturation of both photoendocrine system and brown adipose tissue. 
– MS may be associated with primary disorders of BC. Clinical forms of Mg depletion with hBC in M.S. present diurnal exacerbations and relapses during fair seasons. They have been underestimated because they disagree with the dogma of the “latitude gradient”, presently questioned. Comorbidities with anxiety and migraine are frequent. 
hBC may be treated by using darkness therapy with a balanced Mg status. Absolute light deprivation should only be used only in acute indications and is time-limited. Partial substitutive therapy and chromatotherapy have not been validated yet and are still uncertain. 

Magnesium: out of sight, out of mind?

R. Vink 

Department of Pathology, University of Adelaide, Adelaide, Australia 

Considerable evidence has accumulated firmly establishing that intracellular calcium plays a critical role in the various pathologies that result in cell death in the central nervous system. In contrast, intracellular magnesium does not have such universal acknowledgement as an important factor in neuronal cell death despite considerable evidence to the contrary. Much of this reluctance toward magnesium is due to the fact that few technologies are able to accurately determine free magnesium concentration. Those technologies that have been successfully used often produce widely varying results between different laboratories. On the other hand, indirect evidence using magnesium as a pharmacotherapy has conclusively demonstrated that it is a neuroprotective agent in such diverse pathologies such as traumatic brain injury, stroke, brain oedema, drug induced injury (eg., alcohol, cocaine), migraine, and cerebral palsy, just to name a few. This review will critically analyze the evidence suggesting a ubiquitous role for free magnesium in neuronal cell death, focusing on measurements of free magnesium concentration, its change, and the relationship to functional outcome. 
RV is supported, in part, by the Australian National Health and Medical Research Council 

Variations of magnesium concentrations in psychosis

M. Nechifor¹, C. Văideanu², I. Mîndreci³, C. Borza²  

¹ Dept. of Pharmacology, University of Medicine and Pharmacy “Gr. T. Popa” Iaşi 
² “Socola” Clinical Psychiatric Hospital Iaşi 
³ Biophysics Department, University of Medicine and Pharmacy “Gr. T. Popa” Iaşi, Romania 

Magnesium plays important roles in CNS functioning. Plasmatic and cellular magnesium concentrations are modified in psychosis. In major depression (MD) there are different data regarding Mg concentrations. Some results (Kamei et al., 1998) didn’t show changes in Mg²⁺ concentrations in this disease. Other data (Widmer et al., 1995) show a moderately increase of plasmatic Mg in MD. Our data show that total plasmatic Mg didn’t change significantly in patients with MD vs control group (if are considered all patients with MD), but if are taken into study only patient with severe MD (Hamilton score > 23) than both plasmatic magnesium (17.8 ± 2.1 mg/l in depressive patients vs 22.9 ± 2.1 mg/l in control group, p < 0.05) and erythrocytic magnesium levels decrease significantly (44.1 ± 2.7 mg/l in depressive patients vs 59.1 ± 3.2 mg/l in control group, p < 0.05). In our study, therapy with amitryptiline, 3X 25 mg p.o/day, 4 weeks or sertraline (Zoloft^R) 150 mg/day p.o, 4 weeks enhances significantly plasmatic and erythrocytic magnesium in patients with severe MD (Nechifor et al., 2003, 2004). This fact is associated with an increase in zinc concentrations, significantly decreased in all patients with MD. In paranoid schizophrenia, our data show moderately decreased magnesium level in erythrocytes (48.2 ± 4.5 mg/l in patients with schizophrenia vs 58.41 ± 4.8 mg/l, p < 0.05 in control group). Concentrations of erythrocytic magnesium increase after 30 days of therapy with haloperidol. In bipolar disorder data are variable. Frazer et al., 1983 have found a total Mg plasmatic concentration higher than in normal subjects. Plenge and Rafaelson, 1982 have shown that therapy with Li⁺ (that alleviate mania) increases renal elimination of Mg²⁺ Layden et al., 2000 observed a competition between Li⁺ - Mg²⁺ for Mg²⁺ binding sites in neurons. Abukhdeir et al., 2003 sustain that in the presence of Li +, increases interneuronal concentrations of Mg²⁺. We consider that fluctuation in plasmatic and cellular magnesium levels play a role in the pathogeny of psychosis. 

Serum magnesium concentrations in migraine with aura

M. Cojocaru¹, Inimioara Mihaela Cojocaru², Camelia Muşuroi², Mihaela Botezat², Livia Lazăr², Alina Druţă²  

¹ Central Clinical Laboratory Colentina 
² “Carol Davila” University of Medicine and Pharmacy, Clinic of Neurology, Colentina Clinical Hospital Bucharest, Romania 

The aim of this study was to clarify the relationship between serum magnesium concentrations and migraine with aura. The study included forty patients with migraine with aura (27 women and 13 men), mean age 52 ± 5 years, and 18 healthy, sex- and age-matched subjects as controls. The serum magnesium concentrations were evaluated by Vitros 750 XRC, Johnson, Johnson kit (Ortho Clinical Diagnostics). 
Data are expressed as arithmetic mean (x) ± standard deviation (SD). The Student’s t-test were used for statistical comparison between mean values of magnesium and considered statistically significant at p < 0.05. 
Serum magnesium concentrations of the migraine patients and controls were 0.65 ± 0.07 mmol/l and 0.89 ± 0.08 mmol/l, respectively (p < 0.001). Serum magnesium concentrations were below the normal reference range in 47.4% of the migraine patients and 12.7% of the control subjects. The reasons of magnesium deficiency in migraine attacks are not yet clear. The role of various effects of low magnesium levels in the development of migraines with aura remains to be elucidated. Low magnesium levels may potentiate the sensitivity of the N-methyl-D-aspartate (NMDA) receptor to glutamic acid (Glu), a neuroexcitatory amino acid in the brain. Our results suggest that magnesium may be involved in migraine pathophysiology. 
We feel that a trial of oral magnesium supplementation can be recommended to a majority of migraine sufferers. 
Further clinical and experimental studies will be necessary to elucidate the role of magnesium in the pathogenesis of migraine.

Effect of magnesium on neural activities in cultured rat cortical and hippocampal neurons

K. Torimitsu, N. Kasai, Y. Furukawa 

NTT Basic Research Laboratories, Kanagawa, Japan 

Effects of magnesium on neural activities were investigated in cultured rat cortal and hippocampal neurons. Measurements have been mostly carried for dissociated cell cultures under low magnesium conditions. Cultured slice preparations were also used for experiments. Low magnesium induced spontaneous electrical activities and glutamate release was investigated by using 64-channel planar microelectrode array (PMEA). Each electrode was 10-20 µm square in size. Flow-cytometeric potentiometry using fluorescent probe was also used for membrane potential analysis. Enzyme modification of PMEA with electrochemical detection allowed us to detect transient changes in glutamate release. Glutamate oxidase was used for detection. Calcium transients were measured with Fluo-4-AM under a multi-photon laser microscope. ATP involvements were also investigated. Embryonic cortex and hippocampus from E18 Wistar rats were dissociated with papain. They were cultured in the medium containing DMEM and heat-inactivated horse/fetal bovine serum for 2-3 weeks. Hippocampal slices were obtained from postnatal rat and cultivated on a porous membrane for about a week. Spontaneous activities of the neurons were highly activated by a low magnesium concentration (LMGC). Spatial distribution of their activities indicated an area-dependent response with PMEA. Frequency modulation of intracellular Ca transients and transient increase in glutamate release was also observed. Modulation of synaptic activities through NMDA receptor depending on the extracellular magnesium concentrations was considered. ATP involvement in the magnesium-related synaptic modulation will also be discussed. 

Protective effects of magnesium and orotic acid on the cardiovascular system and brain functions

H.G. Classen 

University of Hohenheim, Stuttgart, Germany 

Hypomagnesaemia is present at serum/plasma-Mg concentrations < 0.76 mmol/L and occurred at a frequency of 14.5% in an unselected German population of 16,000 individuals. Suboptimal levels are given at < 0.80 mmol Mg/L. According to ELIN (2001) an evidence-based lower limit of the reference interval should be around 0.85 mmol/L. 
Epidemiological and clinical studies (e.g., NHANES I, ARIC) have shown that low plasma-Mg concentrations are associated with increased cardiovascular risk and cerebrovascular atherosclerosis complications. Various central-nervous functions (tolerance against physical and emotional stressors, sleeping behavour, pain perception, mood, attention and learning capacity) are impaired by co-existing Mg deficit, especially in children and seniors. The underlying mechanism(s) are interactions at the Ca²⁺ and 1VMDA channels, at impaired ionic pumps and impaired membrane functions. 
Orotic acid (OA) is a key intermediate in the biosynthesis pathway of pyrimidines and hence a precursor of RNA and RNA-dependent synthesis of proteins, phospholipids and ATP. Studies on rats revealed improved learning and memory capacity following pretreatment with OA; anoxic cardiac tissues were protected by OA due to increased synthesis of ATP, resp. Mg-ATP. Since Mg and OA exert synergistic actions; beneficial effects of their salt are predictable and have been shown in clinical practice. The salt is poorly watersoluble; this fact explains low laxative effects which are often unwanted, especially in seniors. 

Drug treatment in acute myocardial infarction – the position of magnesium

R.H. Smetana 

University Clinic of Vienna, Department of Internal Medicine IV, Vienna, Austria 

According to the ACC/AHA guidelines for the management of patients with acute myocardial infarction the recommendation is as follows: antithrombotic and anticoagulant therapy; intravenous nitroglycerin for the first 24-48 hours in patients with acute myocardial infarction, prolonged use over 48 hours in patients with acute myocardial infarction, prolonged use over 48 hours in case of recurrent angina; reperfusion therapy such as acute PTCA or thrombolysis, in addition to these agents/procedures other routineously applied drugs such as beta-blockers are an established regimen; calcium channel blockers such as verapamil or diltiazem may be given to patients in whom β-adrenergic receptor blockers are ineffective or contraindicated. In borderline patients the new generation of short-life beta-blockers such as esmolol could also serve as an appropriate substance. The use of intravenous magnesium could be the ideal agent in case that conventional antianginal therapy is not applicable due to aggravation of hypotension. Furthermore, several large trials have shown essential benefit for intravenous magnesium therapy with regard to reduction of life-threatening arrhythmias and left ventricular failure. ACE-inhibitors in the early post-infarction phase are indicated in extended anterior wall infarction and are generally useful. Therefore, the optimal therapy regimen in acute myocardial infarction requires careful titration of antianginal and hypotensive drugs in order to establish equilibrium of pain relief and sufficient myocardial perfusion for the benefit of the patient. Future prospects are focussed on intravenous short-acting betablockers and intravenous magnesium.

The relationships between magnesium deficiency and cardio-cerebrovascular risk factors

I.A. Guţiu¹, L.I. Guţiu²  

¹ Dept. of Medical Emergencies, “Saint Mary” Hospital 
² Dept. of Neurology, Central Military Hospital, University of Medicine and Pharmacy “Carol Davila”, Bucharest, Romania 

Some studies shown that, between the magnesium (Mg) deficiency and increased risk of cardio-cerebrovascular disease exists a relationship. 
The mechanism is still unclear. However, it was demonstrated that Mg deficiency (even only extra cellular) may induce a nonspecific inflammation characterized by: activation of leucocytes and macrophages, freeing of cytokines and free radicals, increased oxidation of lipids and LDL; all are basic mechanisms in atherogenesis. These aspects generated by Mg deficiency (demonstrated in animal experiments) are more difficultly to demonstrate in clinical research. However, some clinical studies confirmed the existence of an interrelationship between the cardio-cerebrovascular risk factors (CVRF) and Mg deficiency. 
In actual conception, CVRF can be classified in traditional risk factors (TRF) such as dyslipidaemia, smoking, arterial hypertension, diabetes, and new risk factor (NRF) such as low level, nonspecific, chronic inflammation, immunity alterations, infections etc. 
We studied the interferences between blood Mg level and CVRF in 127 patients admitted in hospital for cardio-cerebrovascular disease. Mean age of the group was 67.3 ± 10.2 years, 80 (63%) were women, 95 (75%) had coronary atherosclerosis, and 32 (25%) had stroke in their history. The analysis of serum Mg deficiency was effectuated and we stated that only serum cholesterol (r = 0.283, p < 0.02), arterial pressure (r = – 0.258, p < 0.04) significantly correlated with hypomagnesaemia. An analysis between first and last quartiles of Mg level noted a significant difference between some CVRF and patients data such as: cholesterol (199,6 ± 53.8 versus 230.6 ± 62.6, p < 0.05), serum glucose (132.6 ± 53.9 versus 108.7 ± 62.6, p < 0.05), HDL (32.2 ± 8.5 versus 38.0 ± 1.8, p < 0.001), LDL (131.4 ± 44.8 versus 170.0 ± 68.9, p < 0.02), serum creatinine (1.14 ± 0.23 versus 0.94 ± 0.11, p < 0.002), body mass index (26.1 ± 4.8 versus 23.8 ± 4.5, p < 0.01), and increased PCR level (38% versus 23%, p < 0.01). These data, summarily presented, may constitute an original base for discussions concerning the interrelationships between Mg deficiency and CVRF in the patients with coronary disease or stroke. 
Our data together with the other authors sustains idea that in cardio-cerebrovascular disease is necessary a control (even monitoring in special cases) of serum Mg not only of TRF or/and NRF, and a supplementary treatment with this cheap and available ion in deficiency. 

Role of magnesium in essential hypertension in teenagers

G. Sur, O. Maftei

2^nd Pediatric Clinic, University of Medicine and Pharmacy “Iuliu Hatieganu”,Cluj-Napoca, Romania 

Background. Magnesium seems to be involved in the pathogenesis of essential hypertension by decreasing the sympathetic reactivity, cardiac excitability and vascular tone, contractility and reactivity. 
Objective. The authors of this study proposed to asses the reduction of blood pressure values after magnesium supplementation in teenagers with essential hypertension. 
Material and method. We made a retrospective study on 14 children of 14 years to 18 years diagnosed with essential hypertension in 2^nd Pediatric Clinic of Cluj-Napoca, across 2 years (January, 2002 – December, 2003). In these children we excluded all the causes of a secondary hypertension. There were 8 children (57%) with a deficit of magnesium. We administered magnesium (Magnerot 15 mmol/24 hours), to all the children with essential hypertension, for 2 months, in association with a salt-restrictive diet and physical exercises. To those patients without hypomagnesemia, we gave just half of the dose of magnesium. 
Results. All the patients with primary hypertension were adolescents. Their blood pressure values were just 5-10 mmHg over the normal values for their age, but because their familial history was positive for hypertension, we recommended magnesium, diet and sport. There were 5 girls (36%) and 9 boys (64%) with hypertension. Eight of these children had hypomagnesiemia (3 girls and 5 boys). After 10 days of magnesium supplementation, diet and sport, both systolic and diastolic blood pressure values decreased by 10 mmHg, palpitations disappeared, sleep became still. The improvement of the patients’ status and the decline of blood pressure values were more evident in those patients with hypomagnesemia. 
Conclusions. The role of magnesium supplementation in patients with high blood pressure is benefic in most cases. But it is also important to follow a salt-restrictive diet and to practice physical exercise. 

Effects of magnesium sulfate and its association with mepivacaine and antihypertensives on isolated frog hearts

Sanda Mihaela Popescu, Florica Popescu, A.M. Popescu 

UMF Craiova, Craiova, Romania 

Background. Magnesium is an important cation for the human body, and it is used as magnesium sulfate in arrhythmia and ecclampsia. Mepivacaine is used often in dentistry as a proper local anesthetic for hypertensive patients, who could be under treatment with various antihypertensives. 
Objectives. The aim of this study was to observe the effects of magnesium sulfate and its associations with mepivacaine, mepivacaine-enalaprilat, mepivacaine-propranolol, mepivacaine- verapamil, mepivacaine-diltiazem on heart rate and force of contraction of the isolated frog hearts. 
Methods. The hearts were perfused with Ringer-Lock solution and heart activity has been recorded with a “Servogor” potentiometer. The substances were used in the following doses: mepivacaine 0.1 µM, enalaprilat 0.33 µM, propranolol 0.34 µM, verapamil 0.05 µM, diltiazem 0.1 µM. Magnesium sulfate was added in raising concentrations, from 16 nM to 16 mM, until cardiac arrest. Experiments were reproducible and the results were statistically interpreted and transformed into diagrams. 
Results. Magnesium sulfate had a very small effect on heart rate, but in concentrations of 16 µM it depressed inotropism with 50%. The association magnesium sulfate with mepivacaine has preserved inotropism around reference’s values but has depressed heart rate with 50% at 1.6 mM magnesium sulfate. Mepivacaine-antihypertensives associations have determined a negative cronotrop effect of magnesium sulfate, which has been emphasized by concentration’s growing. This action has been powerful for mepivacaine-diltiazem association, while, for mepivacaine-enalaprilat association, negative cronotrop effects have been reduced. Mepivacaine-antihypertensives associations have antagonized negative inotrop action of magnesium sulfate and have maintained ventricular inotropism around reference’s values for small concentrations of magnesium sulfate. Negative inotrop effects of magnesium sulfate have been antagonized obviously even for high concentrations by mepivacaine-propranolol and mepivacaine-enalaprilat associations. Mepivacaine-verapamil association have slightly antagonized cardiodepressive effect of magnesium sulfate in high concentrations while mepivacaine-diltiazem association has determined a pronounced cardiotoxicity of magnesium sulfate in higher concentrations, with disrrhytmia and cardiac arrest.

Modulatory effect of magnesium on the inflammatory response

Y. Rayssiguier, E. Gueux, W. Nowacki, A. Mazur 

INRA, Unité Maladies Métaboliques et Micronutriments, Theix, St Genès Champanelle, France 

The purpose of this review based on studies from our laboratory as well as from others, is to summarise recent findings showing that magnesium modulates cellular events involved in inflammation. Severe experimental Mg deficiency in the rat induces after few days a clinical inflammatory syndrome characterised by PMN and macrophage activation, release of inflammatory cytokines and acute phase proteins and excessive production of free radicals. The effect of various Mg concentrations on ROS production was investigated in vitro. Increasing concentrations of Mg was shown to decrease PMN respiratory burst. Similar observations were made using rat and human PMN. Moreover, in vitro cytokine production by whole blood from human volunteers was decreased by Mg concentration. Thus, increasing external Mg concentration decreases inflammatory response while reduction in the extracellular magnesium results in cell activation. Because Mg acts as a natural Ca antagonist, the molecular basis for inflammatory response in severe Mg deficiency is probably the result of modulation of intracellular Ca concentration. Potential mediating mechanisms include: cellular entry of Ca and priming of phagocytic cells; opening of Ca channels and activation of NMDA receptors; release of neurotransmitters; membrane oxidation and activation of nuclear factor NFκB; dysregulation of the humoral anti-inflammatory response. Inflammation is the biological response of the immune system to variety of aggressions, but a damaging effect occurs when the initial response becomes amplified and then dysregulated. Excessive response may be, for instance, involved in diseases such as atherosclerosis, diabetes, cerebral and myocardial ischemia, septic shock syndrome, severe trauma or skeletal fragility. Few controlled studies exist regarding the therapeutic uses of oral Mg supplementation. Randomised clinical trials are urgently needed to determine whether Mg supplementation will alter the natural history of these diseases states.

Value of raising the magnesium to calcium intake ratio for health

Mildred S. Seelig

Am. Coll. of Nutr., Decatur, GA, USA 

The current official American recommendation for high intakes of calcium (Ca), despite marginal intakes of magnesium (Mg) - which supports Ca/Mg intake ratios of over 4/1 - was adopted in 1997, stemming largely from the intent to protect against osteoporosis, by increasing consumption of nutrients that increase bone mineralization. Not considered is the growing evidence of cardiovascular, neuromuscular, brain, and even bone damage, as well as metabolic disturbances associated with high Ca/Mg ratios in the body - both extracellular (e.c.) and intracellular (i.c.). An early clue to damage associated with dietary Ca/Mg imbalance is demonstration that the peak in ischemic heart disease mortality in American and Canadian men occurred early in the sixth decade of the 20^th century, by which time the Ca/Mg intake had risen from the earlier 2/1 ratio to an over 3/1 ratio. Might the even higher Ca/Mg intake ratio in the United States of recent years have contributed to the failure of two major National Institute of Health studies to prove their intended objectives? One was an attempt to reduce the incidence of eclampsia by substantially raising the Ca intake of pregnant American women. The Women’s Health Initiative (WHI), in a controlled double-blind test of the controversial value of postmenopausal hormone replacement therapy in reducing risks of bone, cardiovascular, and mental diseases of aging women, ignored generally low Mg intakes. Both failures could have been contributed to by estrogen-induced enhancement of thrombogenesis, that may well have been abetted by high plasma Ca/Mg levels (involving Ca-dependent steps in the coagulation cascade and platelet aggregation that are inhibited by Mg). High i.c. Ca/Mg, rather than the normal i.c. ratio that is higher in Mg, is characteristic of the metabolic syndrome (also termed Syndrome X or Insulin Resistance Syndrome). Among the conditions to which the metabolic syndrome contributes are Type II diabetes, essential hypertension, atherosclerosis, dyslipidemia, cardiac dysrhythmias, abdominal obesity and aging. Additionally, it has long been known that Mg deficiency is a major factor in hyperexcitability of the central nervous system and associated syndromes. Recent findings relate beneficial effect of Mg in “spasmophilia” or latent tetany, chronic fatigue syndrome and fibromyalgia, to blocking by Mg of the adverse effect of Ca in neurotransmission. Mg’s efficacy in preventing migraine and other headaches, has been associated with low serum Mg and high i.c. Ca/Mg levels. The protective effect of Mg against brain damage - whether caused by trauma, ischemia, or by the neurotoxic amyloid peptides of Alzheimer’s disease, is counteracted by the deleterious effect of Ca influx into mitochondria of the neurons. Whether maintaining a Ca/Mg intake ratio of about 2/1 will lower the incidence of the aforementioned conditions may have to be explored in countries not unduly influenced by the American emphasis on high supplementation with Ca, disregarding marginal or low Mg intakes. 

Plasma magnesium content in patients with chronic renal failure treated with a lowprotein diet

C. Sánchez¹, E. Planells¹, M. Larrubia³, P. Aranda¹, A. Pérez de la Cruz², C. Asensio², P. Galindo², J. Mataix¹, J. Llopis¹

¹ Department of Physiology, School of Pharmacy and Institute of Nutrition and Food Technology, University of Granada 
² Virgen de las Nieves Hospital SAS 
³ I + D Sanaví, S.A., Granada, Spain

We evaluated possible changes in plasma magnesium content in pre-dialysis patients with chronic renal failure (CRF) treated with low-protein nutritional therapy during 10 months. Balanced diets adjusted to their needs prepared from habitually consumed food or from manufactured (Sanavi®) low-protein dietary products (LPDP) were given to CRF patients, who were included in the study on the basis of the following criteria: blood creatinine > 3 mg/dL, creatinine clearance < 20 min, and stable clinical condition. Patients were divided into three groups: In group 1 (G1, n = 16) patients consumed their regular diet, those in G2 (n = 15) consumed a balanced diet adjusted to their needs, and those in G3 (n = 15) consumed a balanced diet consisting of LPDP. The diets were designed on the basis of the results of a nutritional questionnaire that included 24-hour recall (recorded on three different days) and frequency of consumption. At bimonthly follow-up visits, blood and plasma samples were obtained. Plasma Mg concentrations were measured by atomic absorption spectrometry. Previous studies have reported higher plasma Mg values after six months of treatment in patients who consumed LPDP (p < 0.02). After 10 months there was a tendency toward higher Mg values in G3, but the differences between groups were not significant. No differences between G1 and G2 were seen at the end of nutritional therapy. 
Conclusion. Plasma Mg levels in patients with CRF who consumed the adjusted diet or LPDP tended to remain within normal values for longer regardless of the type of low-protein nutritional therapy.

Comparative study about the blood levels of calcium and magnesium at two groups of elderly persons related to their nutritional intake

Viorica Gavăţ, F.D. Petrariu, C.D. Labă, Adriana Albu, Mariana Luca

Hygiene Discipline, Faculty of Medicine, “Gr.T.Popa” U.M.F. Iaşi, Romania 

We have followed the daily nutritional intake of calcium and magnesium for each person, using the nutritional inquiry method and also the chemical analysis of the food provided for two closed groups (A and B) of elderly persons with a different habitational and nutritional status. In the same time we have analyzed the blood levels of calcium and magnesium in these two groups. The results shows that in the first study group (A) nutritional intake of calcium was lower than requirements especially for women and the nutritional intake of magnesium was lower for males. 
In the second study group (B) situation was similar but the calcium intake / person / day was higher comparative with the first group. 
Blood analysis revealed a higher percentage of persons with hypocalcaemia in the first group comparative with the second group and differences were statistically significant (at p = 0.01). For magnesium levels the registered differences were statistically insignificant. 
Summarizing we have established only a correlation between the nutritional intake of calcium and the calcaemia. For magnesium the nutritional intake was similar in both study groups (magnesium is frequent encountered in food groups) and the blood levels of magnesium were also resemblant.

Importance of dosage and experimental design in trials testing the effect of magnesium supplementation on hypertension

A. Rosanoff 

Independent Scholar, Pahoa, Hawaii, U.S.A. 

Intervention studies with magnesium therapy for hypertensive patients have led to conflicting results. Some studies have shown a significant blood-pressure lowering effect of magnesium while others have not. A comparison of these studies with respect to the dose of magnesium supplement and experimental design lends some understanding to this seeming conflict. 
A Medline search of PubMed was undertaken to find studies testing magnesium supplements’ effect on blood pressure in humans. Full manuscripts for each study were retrieved. Data from Abstracts were collected from each study for dose of magnesium supplement, duration of supplementation and mean effect on blood pressure. Each manuscript was studied for special circumstances of the experimental design, form of magnesium, or subject population that might impact results. Studies’ data were sorted in ascending order of daily magnesium supplement dose and placed in a summarizing table, along with special circumstances, to facilitate analysis. 
Of eleven studies supplementing subjects with 360 mg magnesium per day or less, nine showed no effect on blood pressure. Of the two studies that did show a drop in blood pressure at 360 mg per day dosage, one was conducted on hypertensive adults with long term diuretic use, and the other showed a drop in blood pressure only when Mg supplements were taken after the placebo period in a cross-over design. In contrast, of the eight trials where subjects were given 480 mg or more of magnesium daily, all did lower blood pressure significantly except for one where subjects were repleted with magnesium before the trial. Of all trials, only one “titrated” the magnesium dose with 3-week trials at three different daily doses of magnesium supplementation for each subject; only doses 480 mg or above showed a significant drop in blood pressure. Choice of dosage, use of anti-hypertensive medications and experimental design can impact results in clinical tests of magnesium’s effect on hypertension. 
In conclusion, rather than a conflict, these results show that, in general, daily magnesium supplementation at doses less than 480 mg of magnesium per day will not significantly lower high blood pressure, but doses of 480 mg or more per day will in unrepleted subjects.

The 30-years experience of the cluj-napoca 2^nd pediatrics clinic concerning the children’s deficit in magnesium

N. Miu, Lucia Slăvescu, Mariana Andreica, Mariana Marc, Smaranda Fritea, A. Bizo, M. Mărgescu, G. Sur, Cristina Blag, Daniela Şerban, C. Aldea, D. Deleanu. 

2^nd Paediatrics Clinic, Cluj-Napoca, Romania 

The paper tries to demonstrate the correlation between the magnesium deficit and important aspects of pediatric pathology, studying the cases of 1845 patients. 
The clinical findings and the diseases associated to the magnesium deficit fall into the following categories: 
– neuro-muscular manifestations; 
– cardio-vascular disorders (mitral valve prolapse, heart failure, cardiogenic shock); 
– the magnesium-deficit osteopenic syndrome; 
– the involvement of magnesium in digestive pathology (acute and persisting enterocolitis, functional disorders, Crohn’s disease, malnutrition, hepatic cirrhosis); – magnesium and diabetes mellitus in children; 
– magnesium and bronchial asthma; 
– magnesium and renal pathology; 
– the magnesium involvement in immunity and inflammation. 
The conclusions of each lot of study, the nutritional recommendations, the therapeutic strategy and the results of magnesiotherapy brings further information, sheds more light on magnesium deficit and makes it applicable in everyday practice. 

Magnesium homeostasis in early neonatal period

L. Blaga, G. Panga, I. Lupea, D. Duma, V. Popa 

Neonatology Department, University of Medicine “Iuliu Hatieganu” Cluj-Napoca, Romania 

Early neonatal period is characterized by rapid changes in mineral homeostasis. Magnesium transfer across placenta increase with gestational age, heaving a peack in the 8^th month of pregnancy, thus magnesium levels in cord blood are closely in term and premterm new borns. Aricetta and col. demonstrate that total magnesium levels are higher in preterm than term new-borns. Magnesium level fall in the first two days after birth, than it has a gradual increase during the first month of life. Hypomagnesemia, defined as magnesium values less than 1.6 mg/dl after Loughead studies, is often meet in early neonatal in prematures new-borns and in small for gestational age new-borns, but not so often as hypocalcemia. 
In this paper the authors want to establish the inferior physiological boundary of magnesium in term and preterm new borns and the incidence of hypomagnesemia at 48 hours after birth in low birth weight infants. We have studied 121 new-borns (20 appropriate for gestational age term new borns, 50 small for gestational age term new borns, 26 premature new borns and 25 small for gestational age preterm new borns). Magnesium was determinated at 48 hours after birth by colorimetric method. Magnesium levels are significantly higher in premature new borns than in term new borns (p < 0.005) and insignificantly higher than small for gestational age term and preterm new-borns. The incidence of hypomagnesemia was 19,2% in preterm new-borns with gestational age less than 30 weeks and onely 6% in small for gestational age term new borns. No symptomes have been found. We concluded that magnesium levels are significantly higher in preterm new borns than in appropriate for gestational age term infants. Incidence of hypomagnesemia is higher in premature new borns than in small fo age term and preterm infants. 

Digestive manifestations of magnesium deficiency

P. J. Porr 

3^rd Medical Clinic Cluj-Napoca, Romania 

The classical manifestations of Magnesium deficiency (MD) occur at the level of the skeletal muscles, resulting in spasmophilia under all its forms, but they also occur at the level of myocardium, resulting in various cardiac disturbances and also even at the level of the smooth (visceral) muscles – including the digestive tract. 
At the esophagus MD may induce esophageal spasm, manifested by dysphagia. Gastro-esophageal and duodeno-gastric reflux disease may occur or aggravate because of MD. We have evidenced in a group of patients with reflux esophagitis and MD after Mg substitution therapy the disappearance of clinical manifestations and of the endoscopically evidenced reflux with normalization of the esophageal pH in nearly half of the patients. 
Experimental studies have evidenced the role of Mg in the inhibition of the gastric secretion. This effect is minimized in MD, the consequence being increased gastric acid secretion. A recent study has also confirmed the implication of MD in Helicobacter- positive gastritis. Other studies have evidenced the increase of tissular Mg concentration in gastric cancer, directly related to the evolution of the disease. This has even been proposed as a prognostic factor. 
At the small and especially large bowel, MD aggravates the irritable bowel syndrome. Different studies have evidenced this role, after Mg substitution therapy in a significant percentage we obtained even the disappearance of irritable bowel complaints. Other studies have analysed the role of MD in chronic idiopathic constipation and even in inflammatory bowel disease. 
MD may also affect the muscles of the biliary system. Biliary dyskinesia may occur or become aggravated by MD. In our study the correction by Mg substitution therapy was surprising 100%, as compared to other studies (61-95% efficiency). In another study we have analysed the correction of MD with postcholecystectomy syndrome, also with very good results after Mg substitution therapy. 
Complex correlations exist between MD and chronic alcoholic liver disease. The correlations with different biological liver parameters were analyzed, evolution to cirrhosis, coagulation disturbances in cirrhosis, alcoholic encephalopathy, alcohol dependence a.o. Our conclusion was to administrate Mg in every form of chronic alcoholic liver disease (steatosis, steatofibrosis, steatohepatitis, cirrhosis). 
A peculiar situation is represented by digestive parasitoses. We observed that a MD, even if treated correctly, was not restored as long as a coexisting parasitosis was not cured. 
To conclude, in digestive pathology MD does not have so serious repercussions as for instance in cardiovascular pathology, but an important part of functional pathology of the digestive tract and biliary system is due to MD and will subside following correct Mg substitution therapy.

The development of functional digestive disturbances under magnesium substitute medication

Mihaela Feier-Golcea¹, L. Comes², M. Feier-Golcea³

¹ UMF ,,Iuliu Haţieganu”, Cluj-Napoca 
² 1^st Medical Clinic, Cluj-Napoca 
³ Municipal Hospital Brad, Romania 

Working hypothesis. Stress influences the balance of the magnesium (Mg) ion enhancing its deficiency. Mg deficiency favors neuromuscular excitability and it is involved in the functional digestive disturbances genesis. 
Aim of investigation. The authors aimed at analyzing the development of functional digestive disturbances and the dynamic of serum Mg (SMg) and erythrocytic Mg (EMg), under substitute medication with Mg, in subjects facing psychosocial stress. 
Material and methods. A number of 43 employees of a mining equipment factory were taken under study at the beginning of their unemployment period. The mean age of the study group was 31 years. The sex distribution was 72% females and 28% males. The functional digestive disturbances were assessed by anamnesis. The SMg concentrations were determined by using the Beckman type Cx10 analyzer. The EMg concentrations were determined by using the atomic absorption spectophotometric method. The development of functional digestive disturbances and SMg and EMg concentrations after magnesium substitute medication were noted. The subjects were treated with Magne B₆ (SANOFI), 3x2 tb/day, for 21 days. Magne B₆ contains 470 mg Mg lactate and 5 mg B₆ vitamin. 
Results. In the functional dyspeptic syndrome (nausea, vomiting, meteorism, pyrosis) meteorism was predominant, in 67.44% of the subjects. In the irritable bowel syndrome the constipations was predominant, with 25.8%. The mean value of magnesiemia in these subjects was 2.04 ± 0.191 mg%. The mean value of EMg was 6.164 ± 1.047 mg%. After the substitute medication with Magne B₆, the concentrations of SMg (2.23 ± 0.273) and EMg (6.79 ± 1.304) increased by 9.31% for SMg and by 10,156% for EMg. The substitute medication had a positive influence on the functional digestive disturbances. Meteorism decreased from 67.44% to 13.95%, p < 0.01 (distinctly significant from the statistical point of view). The incidence of constipation decreased from 25.58% to 16.2%, p > 0.05 (statistically insignificant). The therapy influenced pyrosis (0.01 < p < 0.02) and vomiting (0.02 < p < 0.05) the most.
Conclusions. The functional digestive disturbances occurring under psychosocial stress conditions are influenced by Magne B₆ therapy. The decrease of clinical complaints occurred simultaneously with the increase of SMg and EMg concentrations. Overall, the dyspeptic symptoms are influenced better by the substitute medication than the transit disorders. The statistical analysis of the functional digestive disturbances before and after the medication with Magne B₆, using χ² test, reveals the efficiency of substitute therapy and the statistical signification (χ² = 286.55, p < 0.01). 

Can long term Mg supplementation stabilize the progression of diabetic retinopathy in Mg-depleted type 1 diabetic patients?

I. De Leeuw, C. De Block, L. Van Gaal 

University of Antwerp, Antwerp, Belgium 

Background. 20-25% of type 1 diabetic patients (T1dm) have chronic Mg depletion essentially due to imperfect metabolic control.Low circulating Mg levels have been linked to progression to more severe forms of retinopathy (DR). 
Aim of the study. Can long term oral Mg supplementation normalize the Mg status and influence the progression of DR in metabolically stable Mg – depleted type 1 diabetic patients? 
Study Protocol. 110 T1dm with proven Mg-depletion were selected to be randomized in 2 groups: group A received 300 mg Mg⁺⁺ p.o. daily and group B received no supplement during a 5-year follow-up period. Diabetes management was identical in both groups: insulin treatment was adapted in function of HbA1c and BG self-monitoring results. Exclusion criteria and reasons for drop-out were renal insufficiency, recurrent keto-acidosis, intolerance of oral Mg and diseases or drugs interfering with Mg status. Each year staging of DR with fixed criteria was done by same experienced ophthalmologist, who was unaware of the randomisation. Renal function, microalbuminuria, blood-pressure and some parameters of endothelial function were measured each year. 
Results. 97 T1dm finished the study (53 men, 44 women). At the start Anova did not disclose differences between groups A and B in regard of age, duration of diabetes, gender, HbA1c or mean Mg status. After 5 years the metabolic control was not significantly different between groups or compared to the starting values. In group A the circulating Mg levels increased (MgS: p < 0.01, erythrocyte Mg: p < 0.001) but did not change significantly in group B. Staging of DR after 5 years shows a decrease in 6%, a status quo in 80% and a worsening in 14% in group A. In contrast, in group B there was no improvement, 63% of statu quo and a worsening in 37% of the patients (Fisher Exact Test: p < 0.05). These differences could not be explained by changes in blood pressure, incipient diabetic nephropathy or different level of metabolic control. A significant decrease of the von Willebrandt factor (p = 0.0058) in the supplemented group suggests an improvement of the endothelial function. Logistic regression shows a significant effect of the duration of diabetes (p < 0.0001) and the circulating Mg levels (p = 0.0227). 
Conclusions. Under stable metabolic control, long term Mg supplementation is able to stabilize the progression of DR. Further studies are necessary to explain the pathogenetic mechanisms involved.

Magnesium influence on lipid-lowering effect of fenofibrate in noninsulinodependent diabetes mellitus patients

M. Nechifor¹, S. Bistriceanu², M. Scutaru³, D. Chelărescu¹, C. Nechifor⁴  

¹ University of Medicine and Pharmacy “Gr. T. Popa”, Dept. of Pharmacology, Iaşi; 
² General Ambulatory Service, Botoşani 
³ University of Medicine and Pharmacy “Gr. T. Popa”, Human Anatomy Dept., Iaşi 
⁴ Student, University of Medicine and Pharmacy “Gr. T. Popa”, Iasi, Romania 

We searched the influence of magnesium on lipid-lowering action of fenofibrate (Lipanthyl^R) in patients with diabetes mellitus type II and dyslipidemia. In the study were included 2 groups of adult patients of both genders, aging between 20 to 62 years, diagnosed with diabetes mellitus type II. All patients had in the moment of admittance a fasting glycemia over 1.3 g/l. Both groups received treatment for diabetes with glibenclamide (Maninil^R). Group I received Lipanthyl^R 300 mg/day, 45 days. Group II received Lipanthyl^R 300 mg/day and magnesium orotate (Magnerot^R), 500 mg /day, p.o. for 45 days. There were determined cholesterol, LDL, HDL, triglycerides and plasmatic magnesium level before starting antidyslipidemic therapy and after 45 days of treatment. There were determined plasmatic magnesium levels in a group of 25 healthy patients with the same age and gender characteristics as groups with diabetes. Data obtained were statistically interpreted. Magnerot^R administration significantly enhanced plasmatic total magnesium level, 16.3 ± 2.2 mg/l initial vs 22.3 ± 2.5 mg/l after 45 days treatment, p < 0.05. Total decreasing of serum cholesterol were 36.2 ± 3.1 mg% in Lipanthyl^R group vs 51.6 ± 4.2 mg in Lipanthyl^R + Magnerot^R group (p < 0.05). LDL decreasing was 31.5 ± 2.7 mg in Lipanthyl^R group vs 43.8 ± 3.2 mg% in Lipanthyl^R + Magnerot^R group, p < 0.05. There were not recorded significant differences in the effect of decreasing triglycerides level between groups. Mg2 + administration enhances moderately but significantly lipid lowering action of fenofibrate. 

Effects of risk factors for chronic degenerative diseases on magnesium metabolism in human

M. Nishimuta, N. Kodama, E. Morikuni, N. Matsuzaki 

Laboratory of Mineral Nutrition, Division of Human Nutrition, 

The Incorporated Administrative Agency of Health and Nutrition, Tokyo, Japan Magnesium (Mg) deficit has been considered to be important in the etiology of chronic degenerative diseases (CDD) such as hypertension, diabetes, hyperlipidemia and so on. If it is true, risk factors for such disease must affect Mg metabolism. So, we conducted experimental approach to this problem for the last two decades. Overeating is considered to be one of the most important etiologies of CDD, and caused increases Mg and calcium (Ca) in urine. Cold exposure (physical stress), mathematic drill calculation (mental stress) and strenuous physical exercise also caused the same increase. However, mild physical exercise decreased urine excretion of Mg and Ca. 
Ca/Mg ratio in urine may be typically associated with the Mg status. After OGTT, Ca/Mg ratio in diabetic patients is higher than borderline or normal subjects. After the ingestion of butter (60 g) and eggs (300 g), Ca/Mg ratio in freely living students is higher than that fed with diets for metabolic studies. Adding to this, Ca/Mg ratio in urine did not showed circadian variations. So Ca/Mg ratio in urine seems to be an indicator for Mg status in human. 

The behaviour of circulatory magnesium in experimental goitre

Dana Simu¹, G. Drăgotoiu², L. Gozariu²  

¹ Clinical Center of Diabetes, Nutrition and Metabolic Diseases, Cluj-Napoca 
² Clinical of Endocrinology, UMF, Cluj-Napoca, Romania 

We considered opportune to observe the behaviour of circulatory magnesium in the experimental goitre for the identification of new factors involved in endemic goitre ethiopathogeny; this was lacunary studied until now. 
The six adult rats selected groups were differently treated, through supplimentation with magnesium and iodine; the experimental goitre was obtained for all the groups that we administrated synthesis antithyroidian (Methylthiouracil) and confirmed by histologic examination. 
The thyroid volume modifications were studied depending on magnesium and iodine administration. After Methylthiouracil administrated 30 days, 10 mg/dose, the mean of the increased thyroid volume was 128,2 ± 26,7 mg. The thyroid hypertrophy of the group treated with Trimagant 50 mg/dose, (114,8 ± 23,8 mg) is less important than the group that was treated with potasium iodine (133,7 ± 21,7 mg). The iodine (1 tablet/week) and magnesium association wasn’t followed by any modification in thyroid hypofunction produced by Methylthiouracil. 
Magnesium concentration from the serum is not different at any group as comparatively significantly with the witness group 
The erythrocytar magnesium concentration grows up significantly (p < 0,001) in the group treated with Methylthiouracil and Trimagant (5,6 ± 0,8 mg/dl; 5,7 ± 0,5 mg/dl) compared with control-group (4.0 ± 0,2 mg/dl). The increase of erythrocytar magnesium without modification of the serum magnesium concentration, plead for its implication in cellular reaction mechanism in experimental goitre.

Molecular characterization of the CorAMrs2-A1R1 superfamily of magnesium channel proteins

R. Schweyen 

Max Perutz Laboratories, University of Vienna, Austria 

The bacterial CorA protein has been shown by Michael Maguire and colleagues to be the major, constitutively expressed Mg²⁺ transport protein in prokaryotes. We have identified two classes of distant CorA homologs in eukaryotes, named Mrs2 and Alr1. The only apparently conserved features of the CorA-Mrs2-Alr1 superfamily of proteins are two adjacent transmembrane domains in their C-terminal half and a short F/Y-G-M-N amino acid motif at the end of the first of these TM domains. They appear to form homo-oligomeric channels in various membranes, mediating Mg²⁺ influx into cells or organelles. The inside negative membrane potential has been shown to serve as driving force for this ion flux. Members of the Mrs2 family constitute the major Mg²⁺ influx channel in the inner mitochondrial membrane. Their activity has been shown to be essential for mitochondrial function in yeast and for survival of mammalian cells. Functional characterization of conserved domains in Mrs2 proteins is under way. Plant genomes encode up to ten Mrs2 homologs. Besides in mitochondria, they appear to act as Mg²⁺ transport proteins in the plasma membrane and eventually also in other membranes. In fungi, we and others have identified Alr1, a distant homolog of both CorA and Mrs2, as the major Mg²⁺ transport protein. We are presently studying the role of cellular Mg²⁺ concentrations in controlling synthesis and turn-over of Alr2 (via endocytosis from the plasma membrane and vacuolar degradation) as well as the genome-wide expression of other genes. 

Magnesium and calcium-modulated mitochondrial functions

N.-E. L. Saris 

University of Helsinki, Department Applied Chemistry, Microbiology, Viikki Biocenter 1, Helsinki, Finland 

Ca²⁺ is well known to activate a number of mitochondrial enzyme activities such as citric acid cycle dehydrogenases, ATP synthase and some hydrolytic enzymes, including phospholipase A2 (PLAZ). Ca²⁺ is a signal for activating the cell, and the first-mentioned enzymes increase the ATP production needed by the activated cell. Mitochondrial Ca²⁺ homeostasis is regulated by the activities of the uptake mechanism, the calcium uniporter, and efflux mechanisms, the most important being the Ca²⁺/nNa⁺ and the Ca²⁺/nH⁺ antiporters. Mg²⁺ is needed to: 1) modulate the enzyme activities, 2) the transport activities and 3) the [Ca²⁺]. The last one is by competing with Ca²⁺ for electrostatic binding to negative charges in the membrane and to complex formation with ATP and proteins. The activity of PLA2 (both mitochondrial and other) is important for the production of unsaturated fatty acids for prostaglandin synthesis and of palmitic acid. This activity is also influenced by Mg²⁺. 
There are also negative effects of Ca²⁺ on mitochondrial integrity, i.e. swelling, loss of nucleotides, uncoupling, i.e. inhibition of ATP synthesis and stimulation of ATPase activity due to lowering of the transmembrane potential, and stimulation of production of reactive oxygen species. These are associated with the opening of a large pore in the inner membrane when Ca²⁺ is taken up over a certain threshold. This is called the mitochondrial permeability transition (MPT). Mg²⁺ increases the Ca²⁺ threshold and thus keeps the pore closed. Fatty acids, especially palmitic acid, stimulate pore opening. By inhibiting the activation of PLA2, for instance that associated with ischaemia-reperfusion, Mg²⁺ also has a protective function. If MPT occurs in a substantial number of mitochondria, cellular [ATP] may become depleted and the cell may go into necrosis. In apoptosis Ca²⁺ and mitochondria are involved in the signaling, and thereby also Mg²⁺. Proapoptotic factors, cyt. c and apoptosis-inducing factor (AIF) are released with or without MPT, occurring in a restricted number of mitochondria. Apoptosis is of central interest and has made mitochondrial calcium handling and its regulation of renewed interest.

Magnesium and the muscle cells

R. Hunger 

Chur, Switzerland 

The membrane mechanisms Ca ATPase (PMCA, SERCA), Na/Ca exchange (NCX) and Na/K ATPase regulate the Na and the Ca concentration (Cai) of the cytosol in the muscle cell. The magnesium influences the three mechanisms the Ca competition, formation of MgATP and Na/K exchange through Mg and PO4 their interactions. Cai influences the activation of the myosin ATPase with ATP. Skeletal muscle cells: During rest there are no action potentials (AP). Na and Ca are diffusing into the muscle cells. At Mg deficiency the Ca ATPase pumps with ATP the Ca directly out of the cytosol. Because of deficiency of Na at the Na pump the membrane potential (MP) is decreasing. Nightly cramps of the calf may occur. Mg shifts the Ca export to the NCX and the Na pumps improve the MP.At high load the cytosol of the muscle is overloaded with Na and Ca. At decompensation of the membrane mechanisms an increase of the Cai induces muscle cramps. Mg shifts the Ca export from the pump to the more powerful exchange mechanisms. Because of competition of Ca from troponin/ tropomyosin complex the probability to induce cramps and the power of the muscle is reduced. In addition the cell loses Ca. Smooth muscle cell: The balance between pumps and exchange mechanisms regulates the Cai. Mg shifts the Na and Ca export from the pumps to the exchange mechanisms. When the Na/K ATPase is overloaded the Cai increases. Essential hypertonia: Na and Ca are elevated in the cytosol. A Mg Concentration over 1.0 mmol/l decreases Cai. Simultaneously the power of the muscle cell is decreasing, especially the power of the heart muscle. During pregnancy Ca and PO4 are decreased. At Mg deficiency the Na/K ATPase may decompensate and the accumulation of Na inhibits the NCX. The deficiency of PO4 inhibits the ATP production out of ADP and PO4 and decreases the Mg ATP concentration leading to a weakness in the Ca and Na pumps and leading to an increase in the Cai. The voltage of the muscle cell increases despite a reduced MgATP because the acto-myosin complex dissolves delayed by ATP. Optimal Mg values are: 0.7-1.0 mmol/l. Below 0.7 mmol/l Mg there is a danger of MP reduction with increased irritability of the muscle cells. Over 1.0 mmol/l Mg there is a weakness because of Ca competition. 

Magnesium and hearing

J. Vormann¹, M. J. Cevette², K. Franz³  

¹ Institute for Prevention and Nutrition, Ismaning, Germany 
² Department of Otolaryngology Head and Neck Surgery/Audiology, Mayo Clinic Scottsdale, AZ, USA; 
³ Department of Food Science and Nutrition, Brigham Young University, Provo, UT, USA 

The pervasive influence of magnesium on cellular function extends throughout the auditory system. Magnesium deficiency contributes to an increased permeability of the calcium channel in the outer hair cells with a consequent over influx of calcium, an increased production of glutamate, and over stimulation of the NMDA receptor on the auditory nerve. Magnesium deficiency also promotes oxidative damage and decreases glutathione. Other factors that might be important in production of otoacustic damage are reduced blood flow to the cochlea due to increased production of and reactivity to vasoactive substances. Increased susceptibility to noise damage, drug-induced ototoxicity, and auditory hyperexcitability are linked to states of magnesium deficiency. Evidence for these processes has come slowly and direct effects have remained elusive because plasma Mg does not always correlate with its deficiency. Experimental and clinical studies have shown that supplemental magnesium was able to reduce ototoxic events and might be of importance in preventing noise- and drug-induced damage. 

Magnesium in the food chain of plant, animal and man - risks and problems

M. Anke¹, M. Glei¹, R. Mûller²

¹ Institute of Nutrition and Environment, Friedrich Schiller University, Jena 
² Society of Ecology and Environmental Chemistry Ltd., Erfurt, Germany 

The 16-km-thick earth’s crust contains about 20 g magnesium (Mg)/kg. Plants richest in Mg grow on the weathering soils of the Rotliegende and Keuper (dolomite); those poorest in Mg are produced on the pleistocene formations, and granite, gneiss and Muschelkalk sites. The Mg content of drinking water varies with their geological origin (Keuper and loess sites: 57 and 37 mg Mg/L; gneiss, slate and pleistocene sites: < 10 mg Mg/L). 
Mg deficiency in plants occurs on several arable soils, particularly on heavily leached acid diluvial sands. Intercostal lesions (bright yellow with a violet tinge) are typical signs of Mg deficiency in dicotyledons. A locally apparent agglomeration of chlorophyll in Gramineae leads to a pattern resembling a string of beads along the nerves. The Mg content of the vegetation decreases with increasing age. Grains and fruit contain less Mg than the leaves of plants. 
All animal species, including man, require Mg. The element is of great practical importance for the nutrition of wild and domestic ruminants. Grass tetany (or hypomagnesemia) is a complex ruminant disorder, characterized by convulsions rather than spasms. Its occurrence varies with the mineral composition of forage species, soil properties, fertilizing practice, season, temperature, animal species, breed, and age. The plants on which ruminants feed generally deliver less Mg than those eaten by monogastric animals (and humans). This is manifest not only in domestic ruminants (cows) but also in wild species (red deer, fallow deer, moufflons), which suffer from low Mg concentrations of 100 to 1 200 mg/kg dry matter (dm) in grass, bark, twigs, heather and bilberry bushes. 
In human nutrition, all starch- and sugar-rich foodstuffs contain little Mg (200-600 mg/kg dm). Fruits accumulate only modest amounts of Mg (400-1500 mg/kg dm); among the foods rich in Mg are cocoa, coffee and tea (1 000-2 500 mg/kg dm), spices (1 000-6 000 mg/kg dm), and vegetables (1 000-6 000 mg/kg dm). As a rule, animal foodstuffs deliver less Mg to the food chain (500-1 200 mg/kg dm). Beverages can contribute essentially to the Mg supply (beer, tea: 50-100 mg/L). 
The Mg consumption of adults with self-selected mixed and ovo-lacto-vegetarian diets in Central Europe (Germany) and Mexico was determined in duplicate studies (21 test populations). German and Mexican women consumed 200 and 300 mg/d, respectively; men, 250 and 320 mg/d. Vegetarians of the two sexes take in 375 and 475 mg Mg daily, respectively. Supplementing the daily mixed diet of women in a double blind placebo controlled study with 100 mg Mg/d did not change their Mg balance. The Mg-supplemented women increased their fecal excretion by 95 mg/d. The Mg requirement of women was satisfied by an intake of > 200 mg/d. The normative requirement of persons with mixed diet and without genetic disorders of Mg homeostasis amounts to 200 mg/d for women and 250 mg/d for men, which is < 3.0 mg/kg body weight. Persons with genetic disorders of Mg homeostasis have a much higher requirement than humans without such disorders. Four different disease entities with primary hypomagnesemia have been described so far, three of which are also associated with a disturbance in Ca” homeostasis, which is also found in cows. Primary hypomagnesemia can be caused either by an intestinal or a renal defect. Both intestinal and renal defects can be (partially) corrected by oral Mg⁺⁺  (and Ca⁺⁺ ) supplements. 
Women and men with mixed diets and without these generic disorders are recommended to take in 300 and 350 mg/d, respectively. 
Compared to the results obtained by the duplicate method, the calculation of the Mg intake (basket method) overestimates the Mg intake by 30 to 50%. 

Mg-supplementation in soccer players: effects on metal related to antioxidant defence

L. Leal, E. Gómez-Trullen, M. Gálvez, J.L. López-Colón, S. Millán, J. García, J.F. Escanero 

Department of Pharmacology and Physiology, Faculty of Medicine, University of Zaragoza, Spain 

Introduction. Since the 80’s several papers have reported an excessive production of reactive oxygen species (ROS) in the muscle during strenuous physical exercise. However, this overproduction of ROS exercise-induced have not found on submaximal exercise. By other hand, the use of polivitamins and mineral preparations as well as different antioxidants is really extended among the athletes. Magnesium (Mg) supplementation has been used in athletes in order to prevent the losses or borderline deficiencies and recently magnesium has been proposed as an agent that improves athletic performance. 
Purpose. To determine the short-effects (3 hours after administration) and long-effects (7 days after administration) of Mg-supplementation on the selenium (Se), manganesum (Mn), zinc (Zn) and copper (Cu) serum levels after a cycloergometric test in order to establish the possible effects on oxidant stress in athletes. 
Material and methods. Twelve normal subjects belonging to Real Zaragoza C. D., “C” football team at present in Spanish Third Division participated in this study. Their physical characteristics and fitness were: age, 17-20 old; weight, 69.35 ± 5.62 Kg; height, 177.25 ± 4.11 cm and maximum oxygen uptake (VO₂max), 3.43 ± 0.37 L/min. The athletes were submitted to a regular plan of training of 8 hours/week. 
At the beginning of the experiment all subjects performed a cycloergometric test in basal conditions. After a week athletes received a Mg-supplementation (300 mg as magnesium carbonate) and three hours later all of them came back to repeat another cycloergometric test. Mg-supplementation was supplied, at the same doses/day, for a week and then, they performed a new cycloergometric test. 
The ergometric test may be considered as a submaximal exercise and was carried out on a cycloergometer (Fukuda) and consisted of a warm-up period until the control heart rate was 170 beats/min and followed pedalling at this heart rate during 20 minutes. 
Blood was drawn from antecubital vein, before and immediately after the cycloergometric tests. In blood the following parameters were determined: lactate (lactate oxydase method), malondialdehyde (TBARS method) an index of lipid peroxidation due to ROS and magnesium and trace elements (atomic absorption spectrophotometry). Results are expressed as mean + /- SEM. Data were statistically analysed using a two tailed paired t-test. 
Results. Data show decreases in basal serum Mg (p < 0.001) after 7 days of Mg-supplementation respect to the baseline (2.63 ± 0.17 vs 2.18 ± 0.13 mg/dL) and in malondialdehyde levels (p < 0.08) at this time (29.04 ± 6.43 vs 21.04 ± 3.59 umol/L). All trace elements analysed do not vary in basal conditions on Mg-supplementation. 
After exercise, lactate (mmol/L) increased significantly at the end of the cycloergometric test in all experiments (basal: p < 0.0001, 3 hours: p < 0.03 and 7 days: p < 0.02) and Mg remained unmodified (2.18 ± 0.13 vs 2.36 ± 0.23) after 7 days on Mg-supplementation. Malondialdehyde and Mn, Cu and Zn results do not were modified although Se was increased after exercise in basal conditions (p < 0.0006) and on acute (p < 0.09) and chronic (p < 0.03) Mg-supplementation. 
Conclusion. In brief, after 7 days on Mg-supplementation in athletes there is a tendency to decrease the malondialdehyde and Mg levels in serum and this metal could exert some indirect effect on ROS exercise-induced possibly through Se variations in serum, independently of your direct effects on membrane. 

Effect of exercise intensity and training on magnesium status

C. P. Monteiro¹, H. Santa Clara², M.F. Raposo¹, A. Gonçalves², F. Limáo¹, M.J. Laires¹, Y. Rayssiguier³, A. Mazur³, C. Coudray³, E. Gueux³, C. Feillet Coudray³, M. Bicho⁴

¹ Biochemistry Lab., Faculty of Human Kinetics, Lisbon 
² Exercise and Health Department, Faculty of Human Kinetics, Lisbon 
³ Unité des Maladies Métaboliques et Micronutriments, INRA, Clermont-Ferrand, France 
⁴ Genetics Lab., Faculty of Medicine, Lisbon, Portugal 

The influence of exercise on magnesium metabolism seems to vary according to exercise protocols and training condition of the subjects. The purpose of our work was to evaluate the influence of exercise intensity and subjects’ training conditions on plasma magnesium (P-Mg) and urinary excretion of magnesium (U-Mg). 15 competition swimmers (S) and 16 active men (AM) (not involved in any regular sport), aged between 18 and 25 years old, performed a continuous graded maximal exercise test on treadmill with an individualised protocol (ME). 48 h later they exercised on the treadmill at 75% of their maximal heart rate for 30 minutes (SME). Nutritional analysis was performed using a 3 days food record. Blood was collected before, immediately after and 2 hours after the exercise tests. P-Mg values were corrected for plasma volume variation (PVV). Urine samples were collected before and two hours after the tests. Subjects were at fast. Nutritional analysis revealed a Mg intake under 6 mg/kg/day in the two groups. Swimmers showed lower P-Mg (0.789 mM for S vs 0.843 mM for AM; p < 0.05). After ME, P-Mg decreased (0.806 vs 0.754 mM for S and 0.831 vs 0.781 mM for AM; p = 0.000). 2 h later P-Mg returned to the initial values. U-Mg was decreased (2.3 vs 1.5 mmol/g creat, p = 0.000). 48 h later, there were no significant differences compared to basal values. After SME P-Mg decreased significantly (0.825 vs 0.739 mM, for S and 0.893 vs 0,838 mM for AM; p = 0.000); 2 h later P-Mg returned to the initial values and U-Mg was decreased (2.1 vs 1.3 mmol/g creat, p = 0,001). The most relevant correlations observed were between P-Mg variation and lactate variation in ME. 
To conclude, these results suggest: 1) Mg ingestion is below the recommended dietary allowances in the two groups; 2) trained swimmers have lower P-Mg 3) the 2 types of exercise tests seem to mobilise P-Mg into the cellular compartments with renal Mg retention. 

Urea and ammonia levels in serum after a cycloergometric test in athletes on Mg-supplementation

L. Leal, M. Gálvez, M. S. Soria, L. Roda, J. Villanueva, M. Guerra, J. F. Escanero 

Department of Pharmacology and Physiology, Faculty of Medicine, University of Zaragoza, Spain 

Introduction. It is well established that the levels of ammonia in serum increase with exercise and aminoacids may be used as an alternative substrate to the carbohydrate combustion in muscular activity. 
Purpose. To analyse the variations of urea and ammonia after a cycloergometric test in athletes on Mg-supplementation. 
Material and methods. Twelve normal subjects belonging to Real Zaragoza C. D., “C” football team at present in Spanish Third Division participated in this study. Their physical characteristics and fitness were: age, 17-20 old; weight, 69.35 ± 5.62 Kg; height, 177.25 ± 4.11 cm and maximum oxygen uptake (VO₂ max), 3.43 ± 0.37 L/min. The athletes were submitted to a regular plan of training of 8 hours/week. 
At the beginning of the experiment all subjects performed a cycloergometric test in basal conditions. After a week athletes received a Mg-supplementation (300 mg as magnesium carbonate) and three hours later all of them came back to repeat another cycloergometric test. Mg-supplementation was supplied, at the same doses/day, for a week and then, they performed a new cycloergometric test. 
The ergometric test may be considered as a submaximal exercise and was carried out on a cycloergometer (Fukuda) and consisted of a warm-up period until the control heart rate was 170 beats/min and followed pedalling at this heart rate during 20 minutes. 
Blood was drawn from antecubital vein, before and immediately after the cycloergometric tests. In blood the following parameters were determined: lactate (lactate oxydase method), magnesium (atomic absorption spectrophotometry), ammonia (glutamate deshidrogenase assay) and urea (urease method). Results are expressed as mean +/- SEM. Data were statistically analysed using a two-tailed paired t-test. 
Results. Data show decreases in basal serum Mg (p < 0.001) after 7 days of Mg-supplementation respect to the baseline (2.63 ± 0.27 vs 2.18 ± 0.13 mg/dL); however, this metal remained unmodified after exercise (without or with Mg-supplementation). Lactate (mmol/L) increased significantly at the end of the cycloergometric test in all experiments (basal: 2.06 ± 0.45 vs 8.58 ± 3.28 - p < 0.0001 -, Mg-supplementation 3 hours: 2.32 ± 0.59 vs 7.96 ± 3.84 - p < 0.03 - and Mg-supplementation 7 days: 1.91 ± 0.08 vs 8.19 ± 4.19 -p < 0.02-). Urea levels in serum remained unchanged on Mg supplementation and after exercise in relation to basal values (32.36 mg/dL). Finally, ammonia (mg/dL) decreased significantly on Mg-supplementation (basal: 80.27 ± 16.92 vs 28.60 ± 4.00 after 3 hours and 48.40 ± 11.94 after 7 days). After exercise ammonia increased in all test but after Mg supplementation in a smaller quantity. 

Conclusion. In brief, Mg-supplementation in athletes decreased significantly the levels of ammonia in serum. Consequently, Mg may optimise the use of carbohydrates during exercise. This back-up the use of Mg in athletes in order to improve the performance.

Poster abstracts

Estimation of the daily contribution of magnesium, calcium and phosphorus by the consumption of dairy products

R. Cuciureanu, D. Bulea, A. Prunel, M. Pascu 

Environmental & Food Chemistry and Hygiene, Faculty of Pharmacy, University of Medicine and Pharmacy “Gr. T. Popa”, Iaşi, Romania 

Macroelements represent a group of bioelements that are extremely important in order to maintain the health of a body; this statement is confirmed by the inclusion of these mineral elements in most of the metabolic processes and by the increased quantity that is necessary to the body, a necessary quantity which is secured by the food consumption. From the category of macroelements, calcium, magnesium and phosphorus are introduced into the body by the dairy products. 
Dairy products offer the human body important quantities of calcium, magnesium and phosphorus. Magnesium is found in milk having a concentration of 10-12 mg%. The digestive use of magnesium is diminished by the excessive share of calcium and phosphorus. 
Calcium is found in milk as calcium phosphate and calcium caseinate. The calcium quantity is bigger than the phosporus quantity, as the relation Ca/P is of 1:0.8. The aim of the research that has been perfomed so far was to follow the daily share of calcium, magnesium and phosphorus by means of the daily consumption of milk and related products (yoghurt, cheese, hard cheese). The identification of the relation Ca/P and Mg/P allows us to make several statements concerning the digestive use of the three macroelements. 
The contents of calcium, magnesium and phosphorus for the analysed samples are according to the data stipulated in the specialized literature or according to the information on the label of the product: 
– integral milk: 1 232 mg Ca/L, 124 mg Mg/L, 870 mg P/L; 
– yoghurt: 800-1 250 mg Ca/kg, 76-121 mg Mg/kg, 620-870 mg P/kg; 
– hard cheese: 2 450-3 870 mg Ca/kg, 46-220 mg Mg/kg, 2 800-3 000 mg/100 g product. 
These values combine the major importance of including dairy products, which secure an optimal share of macroelements, the basic principle of a balanced alimentation, especially in the diet of certain categories of population.

Comparison of the magnesium content of tap water and the natural mineral waters

O. Voroniuc, D. Diaconu, T. Navrotescu, A.Cojocariu, V. Năstase 

University of Medicine and Pharmacy “Gr. T. Popa” Iaşi, Romania 

Introduction. The importance of magnesium (Mg) intake in drinking water is quantitative and qualitative. Water containing Mg is better and more quickly absorbed than dietary magnesium. This particular availability might help to understand who an adequate water magnesium level may determine a better state of health. 
Objectives. Because of growing concern that constituents of drinking water may have adverse health effects, consumption of tap water has decrease and consumption of mineral bottled water has increased. Our objectives were to 1) estimate the magnesium and other major minerals-calcium, sodium-content in tap water delivered to the population of Moldova territory 2) determine the mineral content of some comercially available bottled mineral waters in the same areas. 
Measurements and main results. The measurement of magnesium content in tap water delivered from both surface and ground sources indicated that, in majority of samples this element is present in low concentrations – 9.01 to 29.7 mg/L with a mean value of 19.25 mg/L. The obtained analytical data concerning the concentration of calcium and sodium in tap water put in evidence the following values: 41.7 to 75.3 mg/L with a mean value of 57.57 mg/L, and 7.9 to 28.5 mg/L sodium. Lower magnesium concentrations were noted in samples obtained from urban drinking supply systems with surface sources. Among the bottled waters that we reviewed, the magnesium concentration ranges from 6.1 to 117.5 mg/L, the calcium content ranges from 15.2 to 368.7 mg/L and sodium content from 17.0 to 25.3 mg/L. The highest level of magnesium was 117.5 mg/L in bottled mineral water “Amfiteatru”, Iasi city, Copou source. We note and other results for the magnesium concentration in the natural mineral waters: “Cristalina” – 15.5 mg/L, “Piton S.R.L” – 82.69 mg/L, Fundu Moldovei, “Bucovina” – 98.5 mg/L, “Carpatina” – 60.8 mg/L, “Poiana Negri” – 47.2 mg/L. 
Conclusions. Epidemiological and clinical studies suggest that magnesium may reduce the frequency coronary disease, that sodium contributed to the occurrence of hypertension, and calcium may help prevent osteoporosis. The ideal bottled mineral water should be rich in magnesium and calcium and have a low sodium content. 

Effect of diets with different magnesium content on homocysteinemia in young and aged rats

V. Gaume, C. Demougeot, M. Adrian, S. Devaux, P. Laurant, A. Berthelot 

Laboratoire de Physiologie, Pharmacologie et Nutrition Préventive Expérimentale, Faculté de Médecine-Pharmacie, Besançon, France 

A considerable number of experimental, epidemiological and clinical studies have pointed out the role of abnormal dietary deficiency of magnesium (Mg) in the etiology of cardiovascular pathology. Up to now, the underlying mechanisms involved in the deleterious effects of Mg deficiency are not fully understood. Many studies have identified a mildly elevated plasma concentration of homocysteine (Hcy) as a risk factor for cardiovascular disease. The aim of this study was to investigate the relationship between the Mg dietary intake and homocysteinemia in rats, as well as the influence of ageing on these two parameters.
Experiments were conducted on 4-week-old Sprague Dawley rats fed with low (0.015%), normal (0.08%) or high (0.32%) Mg diet for 4 months (n = 5-6 per group, young rats) or 21 months (n = 7 per group, aged rats). Plasma concentration of Hcy and total Mg were measured at the end of the experiment by HPLC/fluorimetry and atomic absorption spectroscopy, respectively. 
In rats fed with normal Mg diet, ageing was associated with a 2-fold increase in homocysteinemia (p < 0.01) whereas it did not affect plasma total Mg level. In young rats, Mg deprivation or supplementation did not modify homocysteinemia. Conversely, in aged rats, high Mg diet decreased homocysteinemia by 64% as compared to normal diet (1.48 ± 0.48 versus 4.14 ± 0.40 µM, p < 0.05) whereas low Mg diet had no effect (3.95 ± 0.28 versus 4.14 ± 0.40 µM). Interestingly, plasma Hcy negatively correlated with plasma total Mg level (r = – 0.445, p = 0.04) in aged rats but not in young rats. 
In conclusion, these results demonstrate the existence of a relationship between plasma Mg level and homocysteinemia in aged rats, and suggest that a long-term Mg supplementation is able to modify Hcy metabolism. These data are in favor of a beneficial effect of Mg supplementation for reducing the risk for cardiovascular disease in the elderly.  

Serum magnesium, cholesterol, and triglycerides in relation to dietary magnesium intake in a composite romanian sample of adult population

Mariana Vlad¹, H. Zăpîrţan¹, A. Şinca¹, Emilia Creţeanu¹, A. Zeic¹, P. J. Porr², Teodora Vlad¹

¹ Institute of Public Health Cluj-Napoca 
² 3^rd Medical Clinic, Cluj-Napoca, Romania

Serum magnesium, calcium, iron, total cholesterol, and triglycerides were measured in 269 men and in 479 women aged 20-65. The investigated subjects were selected from 8 counties, from different areas of Romania, with quite different lifestyle and dietary characteristics. Nutritional status of the subjects was assessed using two 24-hour recalls (in spring and autumn), a food frequency questionnaire, anthropometric measurements, clinical check-ups and serum analyses. The nutrient intake of the individuals was compared to the Recommended Dietary Allowances (RDA_s). Mean energy intake was 1,867 ± 466 kcal, the total range being 1,559-2,164 kcal. The mean vitamin and mineral intake of the subjects met the RDA_s, except for vitamin A and calcium. The average intake of magnesium was 328 mg/day which is close to RDA_s (10^th edition). An approximately 1.5-fold difference in total magnesium intake was found between the highest and lowest quintiles within the row of the ranked values (477 mg/day in the highest quintile vs 254 mg/day in the lowest). Carbohydrates, protein and fat average intake covered 70%, 67%, and 66% respectively of the RDA_s. No significant difference between men and women was observed for the mean serum magnesium level. The healthy women and men aged 20-45 had a mean serum magnesium level of 2.0 ± 0.5 mg/100 ml, close to the values found in women and men 46-65 years old. The women had significantly lower serum iron levels then those found in men (p < 0.01). The mean serum cholesterol and triglycerides concentrations were significantly higher in men aged 20-45 than in the women within the same age group (p < 0.01). In conclusion, our study put into evidence that in the studied samples the mean serum magnesium values are within the normal values. The average daily magnesium intake covered the RDA_s mainly due to the presence of fruits, vegetables and cereals in the subjects’ daily diet. Due to the limits of the used procedure, in order to get more representative data, it seems necessary to extend the scope of the study during other periods of the year and at least for one week recalls.

Characterization of a Mg-selective minielectrode for magnesium ionized in biological fluids and aqueous samples

Viorica Cosma¹, Vera Andronic¹, M. L. Rusu², C. Măruţoiu³, Elena Maria Pică⁴  

¹ Research and Production Center “Senzorom”, Cluj-Napoca 
² University of Medicine and Pharmacy “Iuliu Haţieganu” Cluj-Napoca 
³ “Lucian Blaga” University, Sibiu 
⁴ Technical University, Department of Chemistry, Cluj-Napoca, Romania 

Accurate and rapid determination of magnesium in biological and aqueous samples is of great interest. 
A magnesium ion-selective liquid membrane electrode based on a synthetic neutral carrier for ionized magnesium in biological fluids and aqueous samples has been designed is presented to maximize the electroanalytical characteristics of the minisensor, magnesium-selective membrane constituents and their amounts were varied. Magnesium-selective membrane incorporating 3.3%ETH 1117, 28.3% PVC, 66.8% and o-nitrophenylete and 1.6% aditiv lipofil showed the best potentiometric characteristics. 
We have undertaken a number of experimental studies, to characterize the linearity, precision, specificity, accuracy and utility of this ion-selective mini electrode for Mg²⁺. 
The linearity of minielectrode 10^– 1 – 10^– 4 M Mg²⁺ and the selectivity for Mg²⁺ which is sufficient for assays in the physiological range. Pathophysiologic concentrations of Ca²⁺, Na⁺, K⁺, H⁺ or NH4⁺ exhibiting no or negligible effects on the minisenzor response.

In vitro study of magnesium fluxes in rat erythrocytes using a stable isotope of magnesium

A. Chanson¹, C. Feillet-Coudray¹, E. Gueux¹, C. Coudray¹, A. Mazur¹, F. I. Wolf², Y. Rayssiguier¹  

¹ CRNH d’Auvergne, Unité Maladies Métaboliques et Micronutriments, INRA, France 
² Università Cattolica del Sacro Cuore, Facoltà di Medicina, Roma, Italy 

The mechanisms that maintain intracellular Mg concentration at physiologic levels are not fully understood, but, according to electrochemical equilibrium, intracellular Mg content is regulated by efflux rather than influx. A Na⁺ - and ATP-dependent Mg²⁺ efflux via Na⁺/Mg²⁺ antiport and a Na⁺ - and ATP-independent Mg²⁺ efflux were found in erythrocytes loaded with Mg. Recently Ebel and Gunther (Biochim Biophys Acta 1999,14121:353) characterised the Na⁺ - dependent Mg²⁺ efflux in non Mg²⁺ - loaded erythrocytes and demonstrated the participation of a choline/Mg²⁺ exchanger. However, in order to detect net Mg fluxes, all these experiments were conducted in Mg-free medium. In this work, we describe for the first time, a new method that, by using Mg stable isotope, makes possible simultaneous determination of Mg efflux and Mg influx in physiological level of extracellular Mg. Erythrocytes from rats were suspended as a 10% suspension in NaCl medium (NaCl 150 mmol/l, Hepes 10 mmol/l pH 7.4, glucose 5 mmol/l) or choline medium (choline 150 mmol/l, Hepes 10 mmol/l pH 7.4, glucose 5 mmol/l). Various concentrations of ²⁵Mg were tested in these media (0 to 1.6 mmol/L). The effects of amiloride (an inhibitor of the Na⁺ -dependent Mg efflux) and cinchonine (an inhibitor of the choline exchanger) were also investigated. The erythrocyte suspension was incubated at 37°C, and aliquots of the cell suspension were centrifuged at the beginning of the incubation and after 60 and 120 min. ²⁴Mg, ²⁵Mg and ²⁶Mg contents of supernatants and erythrocytes were determined by ICP/MS. Mg efflux and Mg influx were then calculated. We observed a significant Mg efflux and Mg influx in NaCl medium and in choline Cl medium. Mg efflux and Mg influx were inhibited by amiloride in NaCl medium and by cinchonine in choline Cl medium. Moreover, Mg efflux and Mg influx increased with extracellular Mg. Our new experimental approach of the contemporaneous evaluation of Mg influx and Mg efflux showed that Mg fluxes are directly related to the levels of extracellular Mg. Further investigations are necessary to better characterise these fluxes. 

Magnesium modulates microvascular endothelial cell function

J. A. M. Maier¹, A. Nasulewicz^2,3, Y. Rayssiguier³, A. Mazur³  

¹ Department of Preclinical Sciences, LITA Vialba, Universita di Milano, Milan, Italy 
² Department of Tumour Immunology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, PAN, Wroclaw, Poland 
³ Unité Maladies Métaboliques et Micronutriments, INRA, Theix, France 

Evidence has accumulated to suggest that extracellular Mg concentrations play a critical role in modulating endothelial activities. Because microvascular endothelial cells are important players in inflammation and angiogenesis, we asked whether different concentrations of Mg could affect the behavior of these cells. We found that low Mg concentrations did not induce any stress response and reversibly inhibited endothelial proliferation, while high Mg (up to 5 µM) stimulated cell growth. Similarly, while low Mg impaired endothelial motogenic response to several angiogenic factors, high Mg functioned as a chemoactractant. These results indicate that Mg modulates some crucial events in angiogenesis. In addition, low Mg increased endothelial adhesiveness for monocytes, mainly through an upregulation of VCAM, and rendered the cells more susceptible to the detrimental effect of LPS. On the contrary, high Mg reduced endothelial-monocyte interactions both in unstimulated and in LPS-treated cells. Since adhesion is regulated by pro-inflammatory cytokines, it is noteworthy that we could not describe any modulation of cytokine levels by low Mg as detected by protein array, apart from an upregulation of IL-5. We found that low Mg does not modulate the synthesis of nitric oxide, whereas 5 ìM Mg induces eNOS levels and activity. 
In conclusion, our results demonstrate a direct role of low magnesium in modulating microvascular endothelial behaviour that could play a role in angiogenesis and inflammation. 

Exploration of magnesium metabolism in spontaneously hypertensive rats

C. Feillet-Coudray, C. Coudray, S. Thien, L. Jaffrelo, Y. Rayssiguier, A. Mazur 

CRNH d’Auvergne, Unité Maladies Métaboliques et Micronutriments, INRA, Theix, France 

Numerous studies demonstrated Mg metabolism disturbances in the spontaneously hypertensive rat (SHR), a model for studying hypertension. In this work, we explored the ²⁵Mg enrichment and the Mg fluxes of different blood cells in SHR and WKY. To evaluate ²⁵Mg enrichment, blood from SHR and WKY was incubated with a ²⁵Mg isotope (10 µg/ml) for 2 hours at 37°C, erythrocytes and lymphocytes were isolated and the ²⁵Mg concentration in cells was determined by ICP/MS [1]. To determinate Mg fluxes, erythrocytes from rats were suspended as a 10% suspension in NaCl medium (NaCl 150 mmol/l, Hepes 10 mmol/l pH 7.4, glucose 5 mmol/l), the erythrocyte suspension was incubated at 37°C, and aliquots of the cell suspension were centrifuged at the beginning of the incubation and after 120 min. ²⁴Mg, ²⁵Mg and ²⁶Mg contents of supernatants and erythrocytes were determined by ICP/MS. Mg efflux and Mg influx were then calculated [2].

Our results demonstrated an increase in ²⁵Mg enrichment in lymphocytes of SHR by comparison to WKY, reflecting an increasing cellular request for Mg. We didn’t observed any modification of  ²⁵Mg enrichment in erythrocytes from SHR. However, we clearly demonstrated lower Mg efflux from SHR erythrocytes by comparison to WKY. This work thus demonstrated disturbances of Mg exchanges at the cellular level in spontaneously hypertensive rats. Further works are now needed to elucidate the mechanisms implicated in cellular Mg metabolism disturbances.

Effect of treatment with magnesium orotate in patients with chronic heart failure in early post-operative period after coronary artery by-pass grafting

D. Gaiţă, Silvia Mâncaş, M. Iurciuc, C.A. Sarău, B. Mut, C. Dina, Adina Ionac, D. Cozma, D. Lighezan, Daniela Clipicioiu, Adina Avram, I. Branea, P. Armean, S.I. Drăgulescu 

Institute of Cardiovascular Medicine Timişoara, Romania 

Background. Previous studies demonstrated that magnesium orotate is useful in patients with coronary artery disease. The aim of the study is to observe the effect of magnesium orotate (Magnerot), in the early postoperative period after coronary artery by-pass grafting (CABG) in patients with chronic heart failure (CHF). 
Methods. We evaluated 32 patients (25 males, 7 females; 53 ± 6 years old) with similar clinical parameters: left ventricular ejection fraction 25-35%, in relatively stable condition, 24-48 hours after CABG (6 with 2 grafts, 17 with 3 grafts, 9, with 4 grafts). The study was randomized, single blinded and placebo-controlled. After inclusion, the patients were divided into 2 groups: Group A witch received standard medication and placebo and Group B witch received standard medication plus 2 grams magnesium orotate daily. All the patients were addressed to the cardiac rehabilitation clinic for exercise training. During the follow-up period (8 weeks) we evaluated functional capacity (“Minnesota Living with Heart Failure” and “Dyspnea-Fatigue Index”). Exercise capacity (6 minutes walk test and ergospirometric parameters), echocardiographic data (left ventricular ejection fraction and wall motion) and incidence of cardiac arrhythmia (Holter monitoring). There were no significant differences between groups regarding the baseline data. 
Results. At the final evaluation there were no statistical significant differences between groups regarding quality of life, resting echocardiographic parameters and incidence of supraventricular arrhythmia. The main improvement induced by magnesium orotate is the increase in exercise capacity: exercise duration (12,6 ± 1,4 in Group B vs 11,3 ± 1,3 mini Group A, p < 0,05), maximal oxygen uptake (18,9 ± 2,1 vs 15,6 ± 2,4 ml kg^– 1 min^– 1, p < 0,01), respiratory equivalent of oxygen (38 ± 3 vs 46 ± 4, p < 0,05), oxygen-pulse (0,4 ± 1,5 vs 8,3 ± 1,2, p < 0,01) and distance during walk test (425 ± 32 vs 398 ± 28 m, p < 0.05). We noticed also, only in group B, a significant decrease in the incidence percent of premature ventricular beats (1,9 ± 0,4, baseline, vs 0,7 ± 0,3, final, p < 0,05). 
Conclusion. It is clear that the fragile equilibrium of hemodynamic, early postoperative myocardial ischemia, reperfusion syndrome and the ionic imbalance by high dose of diuretics claim a protective treatment – and this study suggests the benefit of magnesium orotate added to classical anti-ischemic therapy in this special group of patients. 

Erythrocytary magnesium and diastolic impairment of the left ventricle in cardiac hyperkinetic syndrome in young diabetics

M. L. Rusu¹, Adriana Albu¹, Lucica Coldea-Agoston¹, L. D. Rusu¹, Margareta Rusu²  

¹ 2^nd Medical Clinic, UMF Cluj-Napoca 
² Central Lab., 3rd Medical Clinic Cluj-Napoca, Romania 

Diabetes mellitus type 1 (DM1) develops in young and often became complicated with early cardiac involvement. 
Knowing that magnesium is affected in cardiac diseases, we wanted to study the values of erytrocitary magnesium in young diabetics, with the disease metabolically balanced and without obvious cardiac alteration. 
Material and method: the clinical group was consisted by 32 diabetics (20 men, 12 women) mean aged 28.5 ± 0.5 ani and a mean duration of disease of 12.5 ± 0.5 years, compared to 20 controls. The group was clinically examined and then we evaluated the left ventricle activity by Doppler sonocardiograhpy and the E-Mg was measured by the Mann-Yoe method. From the diabetics 12 cases has a hyperkinetic cardiac syndrome (HCS) with basal tahicardia (AV medie: 88 ± 2), mean arterial pressure: 140/90. The results were:

The ophthalmic examination revealed alteration typical to debutant retinopathy in 10 of 12 diabetics with HCS. 
We conclude that is a certain hypomagnesaemia in young diabetics, significantly lower in those with HCS, which could represent either a cardiac risk factor or a marker for a severe evolution of those cases.

Hypomagnesemia in patients with diabetes and ischemic heart disease

M. Onaca, A. Babeş, M. Motocu, N. Negruţiu, A. Onaca 

University of Oradea, Faculty of Medicine, Department of Diabetes, Nutritional and Metabolic Diseases, Oradea, Romania 

Background and aims. The study below is proposed to show the presence of hypomagnesemia at patients with diabetes who have macro-angiopathic abnormalities like the ischemic heart disease, the role played by the Magnesium ion in atherogenesis being well known. 
Material and method. During the study, a group of 60 patients with diabetes was studied, 50 patients with the type 2 and 10 with type 1, all of them being under the evidence of the Diabetes Centre of Oradea. The study had in view the degree of the metabolic control, the presence of the ischemic heart disease, and the serum, urinary and erythrocytic Magnesium levels. The group of witnesses included 30 patients with neither diabetes nor abnormal oral glucose tolerance test. 
Results. Considering the degree of the metabolic control (good, moderate or insufficient), the glicemic values a jeun, 2 hours after meals and the HbA1c values, the patients were divided into 3 categories. 
There were 25 patients with a good metabolic control, 20 of them with the type 2 diabetes, 5 with type 1. These ones were found with the following values for Magnesium: 1.6 ± 0.06 mEq/l in the serum, as well as 5.58 ± 0.3 mEq/l contained in the red cells and 98 ± 10 mg/24 h into the urine. 11 of these patients were diagnosed with ischemic heart disease, 9 of them belonging to type 2 diabetes, while the others 2 to the type 1. 
The group of patients with a moderate metabolic control was formed by 39 persons, (35 with the type 2, 4 with type 1), and here we present their Magnesium values: 1.4 ± 0.05 mEq/l in the serum, 4.8 ± 0.3 mEq/l in the erythrocytes and 120 ± 8 mg/24 h into the urine. 25 of them were diagnosed with ischemic heart disease. 
The patients diagnosed with an insufficient metabolic control were 6, (5 with type 2, 1 patient with type 1), and they presented the following values for Magnesium: 1.3 ± 0.06 mEq/l for the serum, 4.5 ± 0.2 mEq/l into the red cells and 129 ± 5 mg/24 h was contained into the urine. 2 of them presented also ischemic heart disease. 
The group of witnesses was found with almost normal Magnesium values, 2.2 ± 0.5 mEq/l in the serum, as well as 5.5 ± 0.1 mEq/l in the cells and 100 ± 5 mg/24 h into the urinary one. 
Conclusions. The patients with the type 2 of diabetes were found with low values for the serum and erythrocytic Magnesium, these values being interrelated to the degree of the metabolic control and to the appearance of the ischemic heart disease, which is an extra- proof to the well-known implication of Magnesium in atherogenesis and in inducing the coronary spasm as well. 

Therapy with magnerot at type 2 diabetes patients

M. Onaca, A. Babeş, M. Motocu, N. Negruţiu, A. Onaca 

University of Oradea, Faculty of Medicine, Department of Diabetes, Nutritional and Metabolic Diseases, Oradea, Romania 

Background and aims. The current study emphasized the existence of hypomagnesemia at type 2 diabetes patients and the effect of Mg therapy at these patients. Starting with the well known implications of hypomagnesemia in the appearance of the late complications of diabetes (macro and microangiopathy), A.D.A. considered the opportunity of Mg supplementing therapy at type 2 diabetes patients. 
Material and method. A number of 40 type 2 diabetes patients were included in the study (15 patients treated with insulin and 25 patients treated with oral agents). The patients’ age ranged between 40-65 years and the duration of their diseases ranged between 5-15 years. The values of plasmatic and urinary Mg, as well as before meal plasma glucose, cholesterol, blood pressure were measured at the beginning and at the end of the study. 
For a period of 3 months, through the administration of Magnerot 3x1 pill/day, Mg supplementing therapy was applied. 
Study results. Initially, a number of 29 patients showed low levels of plasmatic magnesium (1.47 ± 0.2 mEq/l) values being as low as the level of the metabolic control. A number of 32 patients showed increased levels of eliminated urinary Mg (120 ± 6 mg/24h). Out of the studied batch, 30 patients were afore diagnosed with arterial hypertension and followed the corresponding treatment. The average values of their blood pressure ranged between 155 ± 4 mm Hg (systolic pressure) and 95 ± 5 mm Hg (diastolic pressure). The average value of cholesterol at the beginning of the study was 280 ± 5 mg%. Magnerot was administrated for a 3 months period to all the patients, knowing that there is Mg deficiency at cellular level even if the plasma magnesium level ranged between normal limits. At the end of the study an increase of plasma magnesium level was noted (1.6 ± 0.05 mEq/1). An increase of the hypotensor therapy efficiency was also noted by the improvement of the blood n pressure values (max: 138 ± 5 mm Hg; min: 85 ± 6 mm Hg) as well as the decrease of the cholesterol at blood level (245 ± 4 mg%). 
Conclusions. Patients with type 2 diabetes showed low levels of plasma magnesium which can be improved by the administering of Mg rich products for a period of 3 months. An improvement of the glucose metabolic control, the decrease of blood pressure values and cholesterol were noted.

The pattern of magnesium and calcium metabolism in spasmophylia, hyperthyroidism and osteoporosis

Ileana Duncea, Carmen Georgescu, A. Paul, Georgeta Hazi, G. Drăgotoiu, L. Gozariu 

Clinic of Endocrinology, University of Medicine and Pharmacy “Iuliu Haţieganu”, Cluj-Napoca, Romania 

The concomitant measurement of both serum and urinary magnesium and calcium allows a better assessment of the body pool of these cations. This may be of significant importance in some endocrinopathies such as spasmophylia, hyperthyroidism or osteoporosis, known to involve alterations of the magnesium and calcium homeostasis. In the present work, serum and twenty-four hours-urinary magnesium and calcium were assessed in a total of 367 women admitted at the Clinic of Endocrinology, Cluj-Napoca. Of the 367 subjects, 139 women were asymptomatic and were considered as controls, 143 women presented with various signs of spasmophylia, 49 women were on antithyroid medication for hyperthyroidism and 36 women had osteoporosis. Data were expressed as mean ± SD. The differences between groups were analyzed using the Student’s t two-tailed test. Despite mean serum levels of magnesium and calcium within the normal range, patients with spasmophylia had significantly lower serum concentrations of calcium as compared to controls (p < 0.01). In addition, the concentration of both urinary magnesium and calcium was markedly diminished in this group of patients in comparison to healthy controls (p < 0.0001). No differences in serum levels of magnesium or calcium between controls and patients treated for hyperthyroidism were observed. However, women on antithyroid therapy also had lower concentrations of urinary magnesium and calcium compared to healthy subjects (p < 0.0001). Women with postmenopausal osteoporosis had significantly lower serum and urinary calcium levels in comparison to controls (p < 0.01). A tendency towards lower circulating magnesium levels was noticed in this group of patients but the difference was not statistically significant as compared to healthy controls. However, postmenopausal women had a significantly reduced excretion of magnesium in the urine (p < 0.01). These data confirm the importance of simultaneous measurements of magnesium and calcium in blood and urine in order to define precisely the alterations of both cations associated with some endocrine diseases. 

The relationship of bone mineral density to magnesium intake and metabolism in postmenopausal women

Carmen Georgescu, P. Orbai, Mihaela Negrilă, Georgeta Hazi, G. Drăgotoiu 

Clinic of Endocrinology, University of Medicine and Pharmacy “Iuliu Haţieganu”, Cluj-Napoca, Romania 

Magnesium (Mg) influences both mineral and bone matrix metabolism by effects on hormones and other factors that regulate skeletal and mineral metabolism, as well as by direct effects on bone cells. It has been shown that disorders in which Mg depletion is common associate a high incidence of osteoporosis. The present study was carried out in 71 postmenopausal women (mean age: 62 ± 9 years), outpatients at the Clinic of Endocrinology Cluj, in whom bone mineral density (BMD) was measured by dual X-ray absorbtiometry (DXA) in addition to parameters of Mg metabolism: the concentrations of Mg in serum and urine. The content of Mg in red blood cells was assessed in 30 patients. The dietary Mg intake was discussed with patients and scored. Pearson’s correlation coefficients were used to describe the associations between BMD and parameters of Mg metabolism. The analysis of BMD showed that about 50% of postmenopausal women had osteopenia (– 1SD < score T < – 2.5SD). Neither circulating nor urinary Mg levels were associated to BMD at the lumbar spine or the hip in our study group. However, women with a low Mg intake had lower lumbar spine and femoral neck BMD values, and the correlation between Mg intake and BMD was significant at the hip (r = 0.56, p = 0.01). Thus Mg intake is linked to BMD in postmenopausal women and appears to predict a high risk of osteoporosis.  

Preliminary research on plasmatic and salivary concentration changes of magnesium and other bivalent cations in patients with malign tumors of parotid glands

Irina Grădinaru¹, M. Nechifor², I. Mândreci³, Eugenia Popescu⁴, D. Gogălniceanu⁴  

¹ Complex Oral Rehabilitation Department, U.M.F. “Gr.T. Popa” Iaşi 
² Clinical Pharmacology Department, U.M.F. “Gr.T. Popa” Iaşi 
³ Biophysics Department, U.M.F. “Gr.T. Popa” Iaşi 
⁴ Oral Surgery Department, U.M.F. “Gr.T. Popa” Iaşi, Romania 

We determined the plasmatic concentrations of Mg²⁺, Ca²⁺, Cu²⁺ and Zn²⁺ and the salivary concentrations of Mg²⁺ and Ca²⁺ in 23 patients with malign tumors of parotid glands. The same determinations were done for a group of 25 healthy volunteers (the control group). The control group had a structure on age and gender simillary with that of the studied group. All the patients were adults, aged between 18 and 75 years. They had pathological exams and clinical exams and diagnosed with malign tumors of parotid glands stages II-III. No patient had bone metastases. We investigated the salivary and plasmatic concentrations by spectrophotometry, before the surgical therapy. No patient had chemotherapy or radiotherapy before or during the investigations. The obtained data were statistically interpreted by “t” test. There were not included the patients with cirrhosis, renal insufficiency, the patients treated by diuretics, patients treated by drugs containing cations or patients that could not be feeded. 
The results showed that for the patients with parotid malign tumors the magnesium salivary concentration is significantly increased in comparison to the reference group (5.97 ± 1.04 mg/l for the group with parotid malign tumors vs 3.37 ± 0.65 mg/l for the reference group, p < 0.01). The calcium plasmatic concentrations are smaller for the patients with parotid malign tumors with 20-22% in comparison to the reference group (p < 0.05). Magnesemia for the patients with parotid malign tumors is significantly increased in comparison to the reference group (25.14 ± 1.52 mg/l in patients with parotid malign tumors vs 20.54 ± 1.21 mg/l to the reference group, p < 0.05). The copper plasmatic concentration is significantly increased in patients with parotid malign tumors (1.19 ± 0.38 mg/l) in comparison to the control group (1.03 ± 0.47 mg/l). The plasmatic concentration of Zn²⁺ is significantly decreased in patients with parotid malign tumors (1.38 ± 0.69 mg/l) in comparison to the reference group (1.53 ± 0.75 mg/l). 

Influence of magnesium sulfate in reserpineinduced acute ulcer in rat

V. Şandor¹, V. Cristea², G. Drăgotoiu³, L.T. Krausz¹, C. Luca¹

¹ Department of Pharmacology and Toxicology 
² Department of Immunopatology 
³ Department of Endocrinology, U.M.F. “Iuliu Haţieganu” Cluj-Napoca, Romania 

Foreword. A lot of magnesium compounds are used as antacid in the ulcer medication, in oral administration. Less data exists about the effects on ulcer of the parenteral magnesium. In order to study these effects we used reserpine - induced ulcer model on rats. 
Material and method. We worked with Wistar-Bratislava male rats, between 160-190 g, in standard laboratory conditions. The two groups were chosen, and after an initial 12 hours of starvation (water ad libitum), rats were injected with reserpine, intraperitoneally (i.p.), 5 mg/kg. The control group (n = 10) received saline solution i.p., in the same time with the reserpine, and after 4 hours. The treated group (n = 11) received i.p. magnesium sulfate, two doses of 200 mg/kg, in the same schedule. Animals were harvested after 8 hours from reserpine administration. Gastric mucosa was examined, and the lesion number and severity was recorded. Statistical analysis was performed following parametric (“t” Student) and non-parametric (Mann-Whitney) tests. Null hypothesis was rejected at p < 0.05. 
Results. The treated group has an increased number of ulcers than the control. Moreover, the severity index of the gastric lesions was found to be increased after magnesium sulfate administration.
Conclusions. Magnesium sulfate in 2 × 200 mg/kg i.p. has an aggravating effect on reserpine-induced gastric ulcers in rat. 

Magnesium and biophysical changes of fetal heart

Denise Urzică¹, Dana Dorohoi²

¹ “Cuza Voda” Hospital of Obstetrics-Gynecology Iaşi 
² “Al.I. Cuza” University Iasi, Romania 

Objective. To determine the correlation between Mg and biophysical changes of fetal heart. 
Materials and methods. This study recruited nine women diagnosed with preeclampsia who were receiving Magnesium. Fetal heart activity was recorded. Six grams of Magnesium sulfate in 100 ml 0.9% saline was administered intravenously over 20 minutes, followed by a continuous infusion of 2 g/hour. For each time interval, the basal heart rate, number of accelerations and deceleration, number of minutes of high and low variability, mean minute range variation and the short term variability were measured. 
Results. Maternal serum Magnesium levels were measured within eight hours of initiating therapy. In seven women, the mean serum Magnesium level at eight hours was 5.1 mEq/l. Magnesium crosses the placenta and equilibration between the mother and fetus usually occurs within 3 hours. Seven women had the mean short-term variability approximately 9 milliseconds. Variability is a biophysical indicator of fetal well-being and becomes clinically significant when less than 2.6 ms at which point it has been associated with a decrease in the umbilical arterial pH and an increase in the base deficit. This was determined by infrared spectroscopy. Mean cerebral oxygen saturation may be obtained by measuring the changes in the cerebral concentrations of oxyHb and deoxyHb during uterine contractions. There were positive correlations between mean cerebral O₂ saturation and measurements of pH in both umbilical vessels, and a negative correlation between mean cerebral oxygen saturation and PCO₂ and base deficit. The mean 1 and 5 minute, Apgar scores were greater than 7 and 8, respectively. Our observed decrease in short-term variability may be explained by the larger Magnesium bolus administered in our protocol (6 g). Each patient acted as her own control. Long and medium term variability did not change significantly after Magnesium was administered. Parenteral Magnesium sulfate is an ideal anticonvulsivant in preeclampsia-eclampsia. After administration of Magnesium sulfate, maternal plasmatic levels are increased during pregnancy, especially at the preeclamptic patients because the urinary excretion of the Mg-ion is low at the patients with severe disease. The administration of a 4-6 g dose parenteral subsequently leads to the increase of plasmatic concentration of Mg that moves to the bones and other cells and after about 4 hours, 50% from the parenteral dose is excreted I urine. A continuous parenteral dose of 2 g/dl/h for maintenance is necessary in order to keep on the plasmatic levels of Magnesium. These levels are considered to be therapeutically ones. We used gluconic calcium as antidote for toxicity in two cases. The first sign of Magnesium toxicity was the abolition of patellar reflexes. In the presence of oliguria or of significant renal insufficiency, only the distribution volume determines the plasmatic levels of Magnesium. In these cases, the maintenance of the dose should be reduced or discontinued and the maternal plasmatic levels must be frequently checked in order to prevent toxicity. Long-term variability measured by the variation in the basal heart rate did not change significantly over an hour of Magnesium sulfate therapy. Short-term variability was significantly decreased from 9 ms before treatment to 6 milliseconds 60 minutes after initiation of therapy. Medium-term variability was not significantly different during the study period by any one of the three biophysical indices: the number of accelerations, the mean minute range variation in milliseconds, and the total number of minutes of high variation. 
Conclusion. Magnesium sulfate is one of several drugs thought to affect the fetal heart rate (FHR), particularly its short-term variability. This reduction does not appear to be clinically significant. 

Magnesium and oxidative stress during pregnancy and postpartum

V. Papadopol, I. Palamaru, G. Mâncaş, G. Albu 

Institute of Public Health, Iasi, Romania 

Introduction. Magnesium requirement increases during pregnancy and, if the dietary intake is not adequate, magnesium deficiency can appear. This enhances the susceptibility of lipoproteins to peroxidation. The study aimed to search the relationship between the magnesium status and oxidative stress markers during pregnancy, when the homeostatic mechanisms are disturbed, and about two months postpartum. 
Methods. Serum and erythrocyte magnesium, plasma lipid peroxides, total blood GSH and erythrocyte SOD in a pregnant women group (n = 294) in the first half of pregnancy (10.2 ± 3.6 weeks), in the second half of pregnancy (31.5 ± 3.8 weeks) and postpartum (8.2 ± 2.5 weeks) were determined. The pregnant women were healthy and they were randomly selected (sent by their general practitioners for the routine analyses). 
Results. Serum magnesium, erythrocyte magnesium, plasma GSH decreased and lipid peroxides significantly increased in the second stage of the pregnancy versus the first stage of pregnancy and postpartum period. Erythrocyte SOD was significantly low in the second stage only versus postpartum period. Gestational age negatively correlated with serum magnesium (p < 0.001), erythrocyte magnesium (p < 0.001), plasma GSH (p < 0.05) and positively with total lipid (p < 0.001) and lipid peroxides (p < 0.002). Serum and erythrocyte magnesium did not correlated with oxidative stress markers. 
Conclusions. The study emphasizes the significant decrease of magnesium status simultaneously with antioxidant markers in the second half of pregnancy versus postpartum period and this account for the magnesium supplementation during pregnancy if the bioelement is found at low level. 

The influence of magnesium supplementation on the effort capacity and on intermediary metabolism in trained animals

Adriana Florinela Galea¹, Simona Tache¹, C. Voia²  

¹ University of Medicine and Pharmacy “Iuliu Haţieganu”, Physiology Department 
² University of Medicine and Pharmacy “Iuliu Haţieganu”, Endocrinology Department, Cluj-Napoca, Romania 

Magnesium is an essential mineral to the human body. It is needed for bone, protein and fatty acid formation, making cells, activating B vitamins, relaxing muscles and forming adenosine triphosphate. 
The aim of our paper was to demonstrate the effect of magnesium supplementation on the effort capacity and on some metabolic parameters in trained animals
Material and method. Two groups of 10 rats each, Wistar race, masculine gender, with weight ranging between 160 g-180 g were used into our study. The first group consisted in animals trained for 4 weeks using the swimming test. The second group consisted in animals trained for the same effort as the first group and which were given a magnesium supplement. From the blood samples we determined the following plasmatic parameters: glycemia, lipids, proteins (as indicators of the intermediary metabolism); magnesiemia; lipoperoxides (as indicators of the oxidative stress). 
Results. In the first group we observed rising levels of glycemia, proteins and lipoperoxides as well as decreasing levels of magnesium and lipids. 
In the second group we observed rising levels of glycemia and decreasing levels for proteins and lipids. We noticed no significant changes in magnesium levels along the physical training. Lipoperoxides were significantly reduced respective to the initial values. 
Conclusion. Supplementation with magnesium determines a higher effort capacity and reduces the oxidative stress.

The dynamics of the magnesium from serum and from erythrocytes in physical effort

Adriana Mureşan¹, Daniela-Rodica Mitrea¹, R. Orăsan¹, Irina Chiş¹, Viorica Hodor²  

¹ Department of Physiology, U.M.Ph. “Iuliu Haţieganu” Cluj-Napoca 
² 1^st Medical Clinic, Cluj-Napoca, Romania 

The modifications of the extra- and intracellular magnesium are implicated in physiological and pathological processes, some of them with a big importance in clinical practice. 
The extremely various physiology of the physical effort involves vascular, respiratory, metabolic and cellular modifications in which the magnesium is drawn up beside the calcium, sodium and potassium ions. Magnesium is an antagonistic ion of calcium, an antistress ion and a motor vasoadjuster. The magnesium resources of the organism are more faithfully reflected by the intracellular space, the serous magnesium representing just 1% from the magnesium capital of the organism. 
This study has in view the distribution of the magnesium in the serous compartment and in erythrocytes (intracellular compartment) in animals – adult male rats Wistar breed, 180-200 g weight – put on the physical effort (swimming with resistance through determinable weights, attached to the subject, 1 hour/day, for 3 days). There were used groups consisted of 12 animals. The witness group comprises 12 rats, Wistar breed, 180-200 g weight, which didn’t do physical effort. 
There were measured the main cations from the serum (Mg++, Na+, K+, Ca++), using the autoanalyser Beckman Cx 10 and the Mg + + from the erythrocytes was measured from the blood taken on heparin – through the Man Yoe method. It was made evident, from the analysis of the obtained results, a significantly decrease of the Mg + + from the erythrocytes and an increase of serous magnesium in animals which were put on the physical effort, by comparison with the witness group. There were not made evident the modifications of Na+, K+, Ca++ from the serum by comparison with the witness group. The results of our study are also confirmed by the information from literature, which shows that the physical effort in non-training subjects determines the modifications in the distribution of extra- and intracellular magnesium. 

The influence of magnesium on the athletic performance

Mirela Maria Vasilescu, Ligia Rusu 

University of Craiova, FEFS, Craiova, Romania 

In the present it is admitted that any tissue is capable of producing IGF-I. The increase in IGF-I can contribute to the hypertrophic response of skeletal muscle through direct stimulation of the proteic synthesis and the multiplication of the satellite cells (anabolic effect and myogenic). Zn and Mg facilitates the action of anabolical factors. The decrease in serum concentration of Zn and Mg are amplified by the prolonged physical effort and/or by high velocity. The B₆ vitamin besides the known anabolic effect increase the absorption of Mg and Zn. 
Objectives. Our study was purpose to examine the effects of the administration of Zn – Mg – B₆ complex has on the isometric muscular contraction.
Methods. Twenty athletes have been used (V = 18 ± 2 years, T = 178 ± 3.5 cm; G = 70 ± 2.5 kg), greco – roman wrestlers and athletics practisers, divided in group A – for research purposes (n = 10) and group B – witness (n = 10). For ten weeks, at sleep hours, in a single oral doze it has been administrated Zn (30 mg), Mg (450 mg) and B₆ (10 mg) (following the Brilla and Conte method) to the research group A, and the placebo effect to the witness group B. Initially and after the end of the administration tests have been run to observe the isometric muscular contraction of the hand grip type with the help of a hand – dynamometer TSD 121 C connected to a collecting and data analyzing system BIOPAC MP 150 PC. 
Results. From the data obtained from the two groups of subjects we observe at the end of the study an improvement of the initial maximum contraction with 13.24% at the study group in reference to the 8.33% of the witness group, and also 14.37% to the previous 9.8% at the final maximum contraction. 
Conclusion. The administration of the Zn-Mg-B₆ vitamin complex can contribute to the augmentation of the muscle force. 

Serum calcium and magnesium levels in urban landscape workers

Felicia Grădinariu, Brigitte Scutaru, Valeria Hurduc, Micaela Mărgineanu, Violeta Borza, Mădălina Bohosievici, Carmen Croitoru, Doina Popa 

Institute of Public Health, Iaşi, Romania 

Aim. A cross-sectional epidemiologic study was made upon a group of urban landscape workers in order to determine the influence of the workplace conditions upon their health status. In this paper we analyze the relationship between serum essential cations Ca and Mg and the pathology recorded in these workers, trying to identify in what extent it would be a professionally-induced condition. 
Material and methods. The investigated group consisted of 54 subjects, (55.5% male), with an average age of 37.4 ± 10.9 years and an average length of service in this workplace of 8.6 ± 7.9 years The investigative protocol included: cl inical examination, EKG, electroneuromyography, respiratory functional tests, biochemical and hematological tests. Ca and Mg serum levels were determined by commercial kits provided by Nobis Labordiagnostica SRL Cluj-Napoca (Romania). Risk evaluation was made by noxious substances assays in the workplace air and also by biotoxicological investigations. The results were compared to those of a matched-control group. Statistical analysis was performed using Student’t test. 
Results. 27.7% of the subjects had hypocalcaemia and 9.2% of them had hypomagnesaemia. 7.4% of them had clinical signs of spasmophilia, without any biochemical change. In the subgroup with low serum cation levels, the spasmophilia was present in 63.1% of cases, in 26.3% of them being accompanied by polineuropathy, in 10.5% by anemia and in other 10.5% by allergy. Low levels of serum calcium were associated with inhibited red blood cell superoxide dismutase activity and also with increased levels of serum thiobarbituric acid reactive species. Calcium low levels correlated positively with pathological decreases of sulphate index (r = 0.6533, p < 0.01) suggesting a link with the effects of air pollution from vehicle fuel components, as long as aromatic hydrocarbons exposure induces these decreases. 
Conclusions. In spite of the apparent environmental non-risk area where these subjects are working, their health status is damaged. The work conditions and lifestyle are both acting upon their health quality. That is why it is more difficult to quantify the extent of occupational factors effects.

Hypomagnaesemia and occupational risk in ceramic industry

Felicia Grădinariu, Brigitte Scutaru, Valeria Hurduc, V. Cazuc, Carmen Croitoru, Mirela Ghiţescu, Al. Maftei, Micaela Mărgineanu 

Institute of Public Health, Iaşi, Romania 

Aim. We evaluated the occupational risk in ceramic industry by investigating the health status in relationship with the workplace conditions trying to understand whether hipomagnaesemia is a cause or a consequence of the pathology encountered. 
Material and methods. A group of 81 workers (9% women), with an average age of 38.35 ± 9.45 years and with an average length of service in a ceramic factory of 16.37 ± 9.93 years, was investigated by a complex protocol, including clinical, biochemical and hematological investigations, EKG, pulmonary functional tests and audiometry. Serum Ca and Mg levels were assayed by commercial kits supplied by Nobis Labordiagnostica SRL Cluj-Napoca (Romania). Particulate matter and carbon monoxide were determined in workplace air. 
Results. 15% of the group had serum Mg level of 1.8 mg/dl, 4% of the subjects had hipocalcaemia, and 4% had both Ca and Mg low levels. The abnormal high carboxihemoglobin values found in 9 subjects were all associated with low Mg levels between 1.8-2.1 mg/dl, being a weak correlation between these two markers (r = 0.7133, p < 0.05). Half of the subjects from the subgroup with low serum cation levels had endocrine dysfunction and one third had cardiovascular diseases. 
Conclusions. Health condition is the effect of multifactorial stressors which are acting upon it.

Serum and urinary magnesium and calcium concentration in kidney stones patients before and after extracorporeal shock-wave lithotripsy treatment

Gabriela Gârban¹, Sofia-Georgeta Popescu², Z. Gârban³, P. Drăgan⁴, I. Ionescu⁵, Ariana-Bianca Martău², Adina Avacovici²  

¹ Institute of Public Health, Timişoara 
² Dept. Biochemistry, University “Politehnica” Timişoara 
³ Dept. Biochemistry and Molecular Biology, University of Agricultural Sciences and Veterinary Medicine, Timişoara 
⁴ Urological Clinic, Univ. Med. and Pharm., Timişoara 
⁵ Dept. Biochemistry, National Center for Neuro-Muscular Diseases “Dr. Horia Radu” Vâlcele, Romania 

Kidney stone formation may be considered as a consequence of a dyshomeostasy between inhibitors (citrate, magnesium, pyrophosphate, glycosaminoglycans, zinc, tin, sulfate, fluoride, nephrocalcin a.o.) and promotors (calcium, phosphor, uric acid, oxalate a. o.) of crystallization in the urine. 
The aim of this work was to revel the differences in the Mg and Ca ions serum and urinary concentration before and after extracorporeal shock wave lithotripsy (ESWL) in kidney stone patients for a more efficient metaphylaxy. 
Our study was performed on 24 patients admitted to the Urological Clinic Timisoara with urolithiasis and treated by extracorporeal shock-wave lithotripsy (ESWL). Serum and urine samples were obtained from these patients 48 hrs before and 72 hrs after ESWL treatment. Calcium concentration in urine and serum by volumetric method and magnesium concentration by spectrophotometric method was determined. Analytical data were statistically processed. 
We found the following results: a) increase of magnesiemia (+ 0.29) and calciemia (+ 0.13) after ESWL treatment; b) increase of magnesiuria (+ 0.24) and decrease of calciuria (- 2.08) after ESWL treatment. Our data revealing dyshomeostasis in the serum and urinary Ca and Mg ions concentration before and after ESWL treatment might be correlated with the physiopathology of the lithogenic process and might constitute a clinical guide for metaphylaxy in urolithiasis. 

The influence of magnesium and zinc on experimental induced benign prostatic hyperplasia in rats

M. Nechifor¹, A. Indrei², L. Indrei³, I. Mîndreci⁴, S. Negru¹

¹ Dept. of Pharmacology 
² Human Anatomy Dept. 
³ Nutritional Hygiene Dept. 
⁴ Biophysics Dept, University of Medicine and Pharmacy “Gr. T. Popa” Iaşi, Romania 

We induced benign prostatic hyperplasia in rat with estradiol (E) and testosterone and we searched for Mg2 + and Zn2 + on this.We worked on 9 groups of 8 adult, male, Wistar rats weighing 180-220 g, bred in normal laboratory conditions and fed identically. Group I was for control and did not received any substance. Group II received E, 1.5 mg/kg/day i.p., 21 days. Group III received E, 1.5 mg/kg/day i.p. + Mg²⁺ (Magne B₆), 0.5 mEq/kg/day, 21 days. Group IV received E, 1.5 mg/kg/day i.p. + Zn acetate (ZnAc), 0.5 mEq/kg/day, 21 days. Group V received testosterone propionate (TP), 10 mg/kg/day i.p., 30 days. Group VI received TP 10 mg/kg/day i.p. + Mg²⁺ (Magne B₆), 0.5 mEq/kg/day, 30 days. Group VII received TP 10 mg/kg/day i.p. + ZnAc, 0.5 mEq/kg/day, 30 days. Group VIII received Mg²⁺ (Magne B₆^R), 0.5 mEq/kg/day, 30 days; Group IX received ZnAc, 0.5 mEq/kg/day, 30 days. Magnesium and zinc plasmatic concentrations were determined initially and at the end of the experiment. After 21 or respectively 30 days animals were sacrificed (after Thiopental administration) and prostate removed. The prostates were weighted and reported to the control group (considered as 100%). Their structure was analysed by optical microscopy. E administration determines a significant prostatic hyperplasia (prostatic weight is increase with 278%, p < 0.01 vs control group). Mg²⁺, 0.5 mEq/kg/day, decreases significantly prostatic hyperplasia (182% in group III vs 278% in group II, p < 0.01). Association E + ZnAc, 0.5 mEq/kg/day, did not change significantly prostatic weight (vs group that received only E) (278% hypertrophy in group II vs 299% in group IV). Magnesium decreases significantly also testosterone induced benign prostatic hyperplasia.

Obtaining and characterization of Mg – anthocyanins complexes using as raw material a Sambucus nigra fruit extract

M. Bratu¹, T. Negreanu-Pârjol¹, F. Roncea¹, H. Mireşan¹, S. Porta²  

¹ “Ovidius” University, Faculty of Dentistry and Pharmacy, Constanţa, Romania 
² University of Graz, Institute for Applied Stress Research, Bad Radkersburg, Austria 

Mg²⁺ ions show an appreciable tendency to form complexes in solution with oxygen ligands. For water, acetone and methanol solutions, nuclear magnetic resonance studies have shown that the coordination number of Mg²⁺ is 6, although in liquid ammonia it appears to be 5. The [Mg (H₂O)₆]²⁺ ion is not acidic and can be dehydrated fairy readly. 
Due to the high reactivity of the phenolic B rings, the anhocyanins form easily complex compounds with divalent metallic ions such as Mg²⁺. Such compounds cumulate the specific therapeutic actions of both anthocyanins and Mg²⁺ ions. 
A technologic process for the obtaining of a magnesium – anthocyanin complex was described and developed, using the elderberries extract (Sambucus nigra L.) as anthocyanin source and as magnesium source MgO, in a pH controlled media. 
The chemical characterization of the new anthocyanin-Mg²⁺ complex was accomplished by FT-IR, UV-VIS, electronic spectra and molar electronic conductivity. The FT-IR spectrum shows the presence of phenolic groups, aromatic substituted carbon, symmetric C-O bonds that make evident the coordinative bonds Mg²⁺: anthocyanins at molar ratio 1:1 and the presence of water molecules in the internal ring of the complex. 
The experiments regarding the complex compound acute toxicity via oralis were determined on Wistar rats (males and females) and the results proved that they have a low toxicity and a good tolerance. The LD₅₀ values were over 0.5 g/kg body weight. 
In conclusion: using an original method we obtained an Mg-anthocyanin complex at molar ratio 1:1, the product showing a good tolerance and a low toxicity. This product is estimated to be a dietary supplement. The estimated main therapeutical effect of the product is the prevention of the muscular spasms and of the cardiac arithmia.