Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MAGNESIUM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed1992

Influence of the magnesium content of drinking water and of magnesium therapy on the occurrence of preeclampsia.

A reverse relationship was found between the magnesium content of drinking water, ie. an adequate supply of highly available dietary magnesium, and the occurrence of preeclampsia. Where various parts of a settlement receive their drinking water from different sources (for example, surface water or well water) there may be an important difference in the level of magnesium supply to different population groups. In the population studied here, the occurrence of preeclampsia varied pari passu with the magnesium content of the drinking water in different parts of the city. The results show that during pregnancy the magnesium content of serum and erythrocytes decreases. This decrease may be prevented by magnesium therapy, which lowers the incidence of preeclampsia.

Adult↗
PubMed2004

State of the art of new data on the role of magnesium in brain injury: clinical interest of measurements of total and ionized magnesium.

Despite many research studies on traumatic brain injury, few markers have been applicable to diagnose trauma at tissue concentration. Today, the importance of the magnesium ion in posttraumatic homeostasis of brain is a well-known reality. Magnesium concentration affects a number of secondary injury factors including neurotransmitter release, ion changes, oxidative stress, protein synthesis, and energy metabolism. There are many experimental and clinical studies relating to magnesium status in brain injury. It was considered by some authors that only the total form of magnesium should be measured in brain injury. However, recent studies point out that measurement of the ionized form also aids in the intervention of patients with brain trauma. This review aims to explain the role of magnesium in brain injury and to assess the real status of magnesium through pertinent tests.

Brain Injuries↗
PubMed1989

Effect of magnesium gradient concentration between plasma and dialysate on magnesium variations induced by hemodialysis.

The magnesium gradient concentration between plasma and dialysate was found to be the main factor responsible for the magnesium decrease induced by hemodialysis with a high-flux membrane using a dialysate magnesium concentration of 0.76 mmol.l-1. The changes in magnesium were negatively correlated to the predialysate magnesium concentration difference between plasma and dialysate. The magnesium changes tended to be less pronounced in the presence of an intradialysate protein increase greater than 9.6 g.l-1, reflecting loss of plasma water by ultrafiltration.

Adult↗
PubMed1998

Bronchial reactivity and intracellular magnesium: a possible mechanism for the bronchodilating effects of magnesium in asthma.

1. Increased bronchial smooth muscle contractility with consequent bronchial hyperreactivity are characteristic physiopathological events of asthma. Since magnesium intervenes in calcium transport mechanisms and intracellular phosphorylation reactions, it constitutes an important determinant of the contraction/relaxation state of bronchial smooth muscle. In the present study we investigated the relationship between bronchial reactivity, assessed by methacholine-provocation test, and magnesium concentrations both at extracellular and intracellular levels measured by spectrophotometry. Twenty-two patients with mild-to-moderate asthma and 38 non-asthmatic subjects with allergic rhinitis (24 allergic to Parietaria pollen and 14 allergic to Grass pollen) were recruited to the study. Exclusion criteria included renal failure, hepatic diseases, heart failure and arterial hypertension. 2. The salient finding of our study is that there is a strong positive correlation between bronchial reactivity and the level of intracellular magnesium (r=0.72, P<0.0001), both when the groups are analysed separately or together. Intracellular magnesium concentrations in the group of patients with asthma were significantly lower (1.8+/-0. 01 mmol/l; n=22) when compared with levels in rhinitis subjects allergic to Parietaria (1.9+/-0.01 mmol/l; n=24, P<0.05), and with levels in rhinitis subjects allergic to Grass pollen (2.0+/-0.03 mmol/l; n=14, P<0.05). Serum levels of the ion were similar in all groups. 3. We conclude that the level of intracellular magnesium may be an important determinant of bronchial hyperreactivity, as supported by the significant positive correlation between these two parameters in allergic patients with known bronchial hyperresponsiveness. This finding, in addition to reports of the bronchodilating effects of magnesium administration in patients with asthma, confirms the proposed role of this ion in the pathogenesis and treatment of asthma.

Adult↗
PubMed1982

In Vitro Synthesis of the Chlorophyll Isocyclic Ring : Transformation of Magnesium-Protoporphyrin IX and Magnesium-Protoporphyrin IX Monomethyl Ester into Magnesium-2,4-Divinyl Pheoporphyrin A(5).

Developing chloroplasts of Cucumis sativus L., cv Beit Alpha which were incubated with either Mg-protoporphyrin IX or Mg-protoporphyrin IX monomethyl ester in darkness produced a partially phototransformable protochlorophyllide species that was tentatively identified as Mg-2,4-divinyl pheoporphyrin a(5). S-Adenosylmethionine stimulated Mg-2,4-divinyl pheoporphyrin a(5) formation irrespective of the starting material used. In the case of Mg-protoporphyrin IX monomethyl ester, this stimulation was attributed to the need to remethylate substrate that had been hydrolyzed by an endogenous methylesterase which converts part of the added Mg-protoporphyrin IX monomethyl ester to Mg-protoporphyrin IX.NADP and NADPH stimulated the conversion of Mg-protoporphyrin IX to Mg-2,4-divinyl pheoporphyrin a(5). The conversion required oxygen and was half saturated at 50 micromolar dissolved O(2). The conversion was insensitive to inhibitors of iron-sulfur and heme-containing proteins, to Cu chelators, H(2)O(2), and peroxide scavengers. However, the conversion was extremely sensitive to phenazine methosulfate, methylene blue, and methyl viologen.A decrease of the plastids' ability to convert Mg-protoporphyrin IX to Mg-2,4-divinyl pheoporphyrin a(5) after lysis in 0.1 molar NaCl suggested a requirement for plastid integrity.

Journal Article↗
PubMed2000

Polynuclear magnesium and magnesium-titanium species. Syntheses and crystal structures of [Mg4(mu3,eta2-ddbfo)2(mu,eta2-ddbfo)2(mu,eta1-ddbfo)29eta1-ddbfo2],.

Tetranuclear magnesium complexes with chelating alkoxo ligands have been synthesized with the aim of investigating coordinatively unsaturated magnesium sites able to bind TiX4 (X = Cl, OR), of the type necessary for the formation of the active centers in polymerization catalysts. The magnesium compound [Mg4(mu3,eta2-ddbfo)2(mu,eta2-ddbfo)2(mu,eta1-ddbfo)2(eta1-ddbfo)2] x 2CH2Cl2 (1) (ddbfo = 2,3-dihydro-2,2-dimethyl-7-benzofuranoxide) was prepared by the reaction of MgBu2 with ddbfoH in dichloromethane. Complex 1 exists as a centrosymmetric tetranuclear species with two different types of magnesium centers corresponding to octahedral MgO6 and trigonal bipyramidal MgO5 geometry. Compound 1 is monoclinic, space group P2(1/c), with a = 12.053(2) A, b = 13.323(3) A, c = 17.069(3) A, beta = 98.50(3) degrees , and Z = 4. The reaction of 1 with methanol in tetrahydrofuran (THF) gave compound [Mg4(mu3-OMe)2(mu,eta2-ddbfo)2(mu,eta1-ddbfo)2(eta1-ddbfo)2(CH3OH)5] x CH3OH x THF (2). During this reaction one of the two five-coordinate MgO5 centers in 1 is completed by a methanol molecule and becomes octahedral in 2. Species 2 belongs to the P2(1/n) monoclinic space group, with a = 13.323(3) A, b = 20.768(4) A, c = 27.584(6) A, beta = 104.26(3) degrees , and Z = 4. Compound [Mg4(mu3,eta2-thffo)2(mu,zeta2-thffo)2(mu,eta1-thffo)2[mu-OTi(DIPP)3]2] x 2CH2Cl2 (3) is formed as a result of substitution of two thffo (thffo = 2-tetrahydrofurfuroxide) ligands bonded to the five-coordinate magnesium atom in [Mg4(thffo)8] by bulky OTi(DIPP)3 (DIPP = diisopropylphenolate) groups. Crystals of 3 are monoclinic, space group P2(1/n), with a = 17.069(3) A, b = 18.421(4) A, 17.815(4) A, beta = 90.77(3) degrees , and Z = 4. The X-ray crystal structures of complexes 1-3 are discussed in terms of explaining the role of the coordinatively unsaturated magnesium site in chiral catalyst active center formation.

Journal Article↗
PubMed1989

Physiology of magnesium metabolism and the important role of magnesium in potassium deficiency.

Magnesium, the second most abundant intracellular cation, has several critically important roles in the body. In addition to energy production and maintaining electrolyte balance, magnesium is essential for normal neuromuscular function as well as calcium and potassium transport. Evidence suggests that a deficit of magnesium is closely interrelated to potassium deficiency and refractory potassium repletion. Although the consequences of hypokalemia are widely documented and recognized, it is only recently that the importance of magnesium deficiency as a cause of potassium depletion has gained clinical attention. Because of the association between hypokalemia and ventricular ectopy/sudden death, familiarity with the causes of magnesium loss, as well as enhanced identification and treatment, appear to be important.

Hormones↗
PubMed1986

Use of magnesium hydroxide and low magnesium dialysate does not permit reduction of aluminum hydroxide during continuous ambulatory peritoneal dialysis.

In an effort to reduce the ingestion of aluminum in phosphate-binding antacids, we treated seven patients on continuous ambulatory peritoneal dialysis (CAPD) with low magnesium dialysate and phosphate binders containing both aluminum and magnesium hydroxide. The total amount of phosphate binders prescribed was adjusted to maintain the serum phosphorus at normal levels. The dose of magnesium hydroxide was limited by intolerable gastrointestinal side effects in six of the seven patients. One patient also developed symptomatic hypermagnesemia. When magnesium hydroxide was prescribed in tolerable doses, the mean aluminum dose was not significantly decreased compared with the dose when taking aluminum hydroxide alone. We conclude that substitution of magnesium hydroxide for aluminum hydroxide as a phosphate binder fails to reduce the dose of aluminum in most patients on CAPD.

Adult↗
PubMed1969

Values for tissue magnesium as a guide in detecting magnesium deficiency.

A large-scale survey of the normal magnesium content of various human tissues was carried out to facilitate clinical detection of magnesium deficiency, especially occult deficiency.A review of the literature favours the magnesium content of skeletal muscle as the most reliable index of the body's store of magnesium. There is a significant difference (P < 0.001) in both the serum and erythrocyte magnesium levels between normal pregnant women in the third trimester and the average normal population. The reason for this difference is discussed.

Adult↗
PubMed1990

Historical review of the effects of marginal intake of magnesium in chronic experimental magnesium deficiency.

After the discovery of magnesium as an essential nutrient in 1926, research focused upon the identification of effects of an acute deficiency state and determination of the requirement for the mineral for normal growth and reproduction. In this early work, marginal intakes of magnesium were reported to result in alterations of tissue composition. Since the 1970s, research has shown that the ability to adapt to a marginal intake of magnesium, which is commonplace in developed countries, is limited. In fact, a low intake of the mineral for an extended period of time may be associated with abnormalities in reproduction, growth, and development and may be a factor in the pathogenesis of disorders of neuromuscular, cardiovascular, renal, and immune function. Problems related to the use of pharmacological agents or to trace metals, such as aluminium, may be worsened in the presence of a low intake of magnesium. Evidence presented illustrates that, although physical signs of magnesium deficiency may be absent, that is to say in cases of latent clinical forms, a marginal dietary inadequacy of the mineral over a long period of time could result in significant problems.

Animals↗
PubMed1990

Adverse effect of orally administered magnesium hydroxide on serum magnesium concentration and systemic acid-base balance in adult cattle.

Two cows, 1 with diarrhea and 1 with signs of forestomach outflow obstruction, were treated in part with repeated doses of a commercially available antacid/cathartic preparation containing magnesium hydroxide. Both cows subsequently were determined to have hypermagnesemia, along with severe metabolic alkalosis. In addition, each cow was comatose at the time of death. A clinical study was initiated to investigate the causal relationship between the ingestion of magnesium hydroxide and the generation of hypermagnesemia and metabolic alkalosis in adult cows. Twelve healthy mature cross bred beef cows were allotted at random to a fed or fasted (simulated anorexia) group, with 2 untreated and 4 treated cows in each group. A single dose of magnesium hydroxide (1.5 g/kg of body weight, suspended in 3.8 L of warm water) was administered per os to each treated cow, whereas each control cow was given only water. Individual determinations of selected venous blood gas values (plasma bicarbonate ion [HCO3-] concentration, and base excess [BE]), serum magnesium (Mg) concentration, and urine magnesium fractional clearance ratio (Mg-FCR) were made immediately before drug administration, and at 2, 4, 8, 12, 24, and 36 hours after treatment. Compared with control values at the conclusion of the study, mean serum Mg concentration, urine Mg-FCR, plasma HCO3- concentration, and BE were significantly higher (P = 0.0001, P = 0.0015, P = 0.028, and P = 0.021, respectively) in treated cows.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1980

Renal magnesium transport and the effects of hypermagnesemia, hypercalcemia, body magnesium stores and parathyroid hormone.

Magnesium reabsorption occurs throughout the proximal, loop and distal segments of the nephron. The proximal tubule is less permeable to magnesium than calcium and sodium and most of the filtered load is reclaimed in the thick ascending limb of the loop of Henle. Thus one would expect that factors which regulate magnesium reabsorption should act within this important segment. No single hormone or agent appears to regulate magnesium reabsorption sufficiently to account for urinary changes; rather it appears to be a number of intracellular and extracellular factors acting in concert to effect day to day magnesium homeostasis.

Absorption↗
PubMed1990

[Studies on cultured rat mesangial cells using cyclosporin A and magnesium--is magnesium nephroprotective in cyclosporin A therapy?].

One serious side effect of Cyclosporine A therapy is its acute nephrotoxicity characterized by a marked decrease in the glomerular filtration rate. A main determinant of the glomerular filtration rate is the ultrafiltration coefficient which is thought to be regulated by the contractile state of the cells of the mesangium. Cyclosporine A enhances contractions of mesangial cells elicited with angiotensin II. By way of lowered ultrafiltration coefficient this effect of Cyclosporine A may be partly responsible for its acute nephrotoxicity. Hypomagnesaemia is often associated with Cyclosporine A therapy. Profound tubular magnesium wasting by Cyclosporine A has been claimed its cause. We have investigated the effect of low and high magnesium concentration on the contractility of mesangial cells pretreated with Cyclosporine A. Without magnesium 80% of the cells contracted upon addition of angiotensin II. A marked decrease in the contractility was seen when the magnesium concentration was elevated to 2 mmol/l (34%). From these observations we conclude that magnesium serum levels even in the high normal range might be protective against the decrease of the glomerular filtration rate seen with CsA therapy.

Angiotensin II↗
PubMed1999

Magnesium insertion by magnesium chelatase in the biosynthesis of zinc bacteriochlorophyll a in an aerobic acidophilic bacterium Acidiphilium rubrum.

To elucidate the mechanism for formation of zinc-containing bacteriochlorophyll a in the photosynthetic bacterium Acidiphilium rubrum, we isolated homologs of magnesium chelatase subunits (bchI, -D, and -H). A. rubrum bchI and -H were encoded by single genes located on the clusters bchP-orf168-bchI-bchD-orf320-crtI and bchF-N-B-H-L as in Rhodobacter capsulatus, respectively. The deduced sequences of A. rubrum bchI, -D, and -H had overall identities of 59. 8, 40.5, and 50.7% to those from Rba. capsulatus, respectively. When these genes were introduced into bchI, bchD, and bchH mutants of Rba. capsulatus for functional complementation, all mutants were complemented with concomitant synthesis of bacteriochlorophyll a. Analyses of bacteriochlorophyll intermediates showed that A. rubrum cells accumulate magnesium protoporphyrin IX monomethyl ester without detectable accumulation of zinc protoporphyrin IX or its monomethyl ester. These results indicate that a single set of magnesium chelatase homologs in A. rubrum catalyzes the insertion of only Mg(2+) into protoporphyrin IX to yield magnesium protoporphyrin IX monomethyl ester. Consequently, it is most likely that zinc-containing bacteriochlorophyll a is formed by a substitution of Zn(2+) for Mg(2+) at a step in the bacteriochlorophyll biosynthesis after formation of magnesium protoporphyrin IX monomethyl ester.

Acetobacteraceae↗
PubMed2004

The influence of some antipsychotics on erythrocyte magnesium and plasma magnesium, calcium, copper and zinc in patients with paranoid schizophrenia.

OBJECTIVE: The aim of the study was the investigation of plasma magnesium, calcium, copper and zinc and erythrocyte magnesium levels in patients with paranoid schizophrenia and the influence of the therapy with two antipsychotic drugs (haloperidol and risperidone) on these concentrations. METHODS: We investigated the influence of treatment with haloperidol and risperidoneon plasma and erythrocyte magnesium and on plasmatic levels of zinc, calcium and copper on hospitalized 56 patients diagnosed with paranoid schizophrenia (DSM IV). RESULTS: Our data indicate a decrease of erythrocyte magnesium levels in schizophrenic patients (4.82 +/- 3.1 mg/L vs. 59.2 +/- 1.1 mg/L in control group, p < 0.01). The plasma level of magnesium was unchanged (18.9 +/- 2.17 mg/L in schizophrenic patients vs. 18.26 +/- 1.9 mg/L in control group). CONCLUSIONS: We consider plasma Cu(2+)/erythrocyte Mg(2+) and plasma Cu(2+)/Zn(2+) ratio two important biological markers of the acute paranoid schizophrenia.

Adolescent↗
PubMed1999

Cooperative effects of potassium, magnesium, and magnesium-ADP on the release of Escherichia coli dihydrofolate reductase from the chaperonin GroEL.

Previous investigation has shown that at 22 degrees C and in the presence of the chaperonin GroEL, the slowest step in the refolding of Escherichia coli dihydrofolate reductase (EcDHFR) reflects release of a late folding intermediate from the cavity of GroEL (Clark AC, Frieden C, 1997, J Mol Biol 268:512-525). In this paper, we investigate the effects of potassium, magnesium, and MgADP on the release of the EcDHFR late folding intermediate from GroEL. The data demonstrate that GroEL consists of at least two conformational states, with apparent rate constants for EcDHFR release that differ by four- to fivefold. In the absence of potassium, magnesium, and ADP, approximately 80-90% of GroEL resides in the form with the faster rate of release. Magnesium and potassium both shift the distribution of GroEL forms toward the form with the slower release rate, though cooperativity for the magnesium-induced transition is observed only in the presence of potassium. MgADP at low concentrations (0-50 microM) shifts the distribution of GroEL forms toward the form with the faster release rate, and this effect is also potassium dependent. Nearly identical results were obtained with a GroEL mutant that forms only a single ring, demonstrating that these effects occur within a single toroid of GroEL. In the presence of saturating magnesium, potassium, and MgADP, the apparent rate constant for the release of EcDHFR from wild-type GroEL at 22 degrees C reaches a limiting value of 0.014 s(-1). For the single ring mutant of GroEL, the rate of EcDHFR release under the same conditions reaches a limiting value of 0.024 s(-1), suggesting that inter-ring negative cooperativity exists for MgADP-induced substrate release. The data suggest that MgADP preferentially binds to one conformation of GroEL, that with the faster apparent rate constant for EcDHFR release, and induces a conformational change leading to more rapid release of substrate protein.

Adenosine Diphosphate↗
PubMed1977

Magnesium-fluoride interrelationships in man. I. Effect of fluoride on magnesium metabolism.

Metabolic balances of fluoride and magnesium were determined in man in control studies and during fluoride supplementation. The studies were carried out during three intake levels of calcium (200, 1,400, and 2,200 mg/day) and during two intake levels of phosphorus (800 mg and 1,400 mg/day). The intake of about 10 mg fluoride per day, given as NaF, resulted in a two- to threefold increase of the urinary and fecal fluoride excretion. However, during the high fluoride intake, the urinary magnesium remained about the same, the fecal magnesium increased slightly, and the magnesium balances did not differ significantly. This was the case whether fluoride was given during a low or high calcium intake in the absence or presence of added phosphorus. Similar results were obtained with large doses of fluoride (40-45 mg/day) given to patients with osteoporosis. The studies have shown that supplemental fluoride ranging from 10 to 45 mg/day did not affect the magnesium balance during calcium intakes that ranged from 200 to 2,200 mg/day and during phosphorus intakes that ranged from 800 to 1,400 mg/day.

Calcium, Dietary↗