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PubMed1987

Magnesium levels in cardiac arrest victims: relationship between magnesium levels and successful resuscitation.

Multivariate analysis was performed to evaluate significant differences between electrolytes, serum magnesium, and successful resuscitation in cardiac arrest victims in a prospective controlled study. Twenty-two cardiac arrest victims having ventricular fibrillation or tachycardia, electromechanical dissociation, or asystole were compared with 19 matched controls with no ventricular arrhythmias. Of the control group, one was hypermagnesemic (5%), 17 normomagnesemic (90%), and one hypomagnesemic (5%). In the arrest group, eight were hypermagnesemic (36%), nine normomagnesemic (41%), and five hypomagnesemic (23%). Thirteen of 22 cardiac arrest victims (59%) had an abnormal serum magnesium level. All hypermagnesemic and hypomagnesemic patients expired (100%). In the normomagnesemic group, four out of nine (44%) were successfully resuscitated. A positive correlation was identified between normomagnesemia and successful resuscitation (P less than .01). There was no correlation between other electrolytes and successful resuscitation (P greater than .05).

Arrhythmias, Cardiac↗
PubMed1999

Effect of chronic magnesium supplementation on magnesium distribution in healthy volunteers evaluated by 31P-NMRS and ion selective electrodes.

AIMS: The role of magnesium (Mg) intake in the prevention and treatment of diseases is greatly debated. Mg biodistribution after chronic Mg supplementation was investigated, using state-of-the-art technology to detect changes in free ionized Mg, both at extra- and intracellular levels. METHODS: Thirty young healthy male volunteers participated in a randomised, placebo (P)-controlled, double-blind trial. The treated group (MgS) took 12 mmol magnesium lactate daily for 1 month. Subjects underwent in vivo 31P-NMR spectroscopy and complete clinical and biological examinations, on the first and last day of the trial. Total Mg was measured in plasma, red blood cells and 24 h urine ([Mg]U ). Plasma ionized Mg was measured by ion-selective electrodes. Intracellular free Mg concentrations of skeletal muscle and brain tissues were determined noninvasively by in vivo 31P-NMR at 3T. NMR data were automatically processed with the dedicated software MAGAN. RESULTS: Only [Mg]U changed significantly after treatment (in mmol/24 h, for P, from 4.2+/-1.4 before to 4.1+/-1.3 after and, for MgS, from 3.9+/-1.1 before to 5. 1+/-1.1 after, t=2.15, P=0.04). The two groups did not differ, either before or after the trial, in any other parameter, whether clinical, biological or in relation with the Mg status. CONCLUSIONS: Chronic oral administration of Mg tablets to young healthy male volunteers at usual pharmaceutical doses does not alter Mg biodistribution. This study shows that an adequate and very complete noninvasive methodology is now available and compatible with the organization of clinical protocols which aim at a thorough evaluation of Mg biodistribution.

Adult↗
PubMed2002

The central role of magnesium deficiency in Tourette's syndrome: causal relationships between magnesium deficiency, altered biochemical pathways and symptoms relating to Tourette's syndrome and several reported comorbid conditions.

Prior studies have suggested a common etiology involved in Tourette's syndrome and several comorbid conditions and symptomatology. Reportedly, current medications used in Tourette's syndrome have intolerable side-effects or are ineffective for many patients. After thoroughly researching the literature, I hypothesize that magnesium deficiency may be the central precipitating event and common pathway for the subsequent biochemical effects on substance P, kynurenine, NMDA receptors, and vitamin B6 that may result in the symptomatology of Tourette's syndrome and several reported comorbid conditions. These comorbid conditions and symptomatology include allergy, asthma, autism, attention deficit hyperactivity disorder, obsessive compulsive disorder, coprolalia, copropraxia, anxiety, depression, restless leg syndrome, migraine, self-injurious behavior, autoimmunity, rage, bruxism, seizure, heart arrhythmia, heightened sensitivity to sensory stimuli, and an exaggerated startle response. Common possible environmental and genetic factors are discussed, as well as biochemical mechanisms. Clinical studies to determine the medical efficacy for a comprehensive magnesium treatment option for Tourette's syndrome need to be conducted to make this relatively safe, low side-effect treatment option available to doctors and their patients.

Humans↗
PubMed1997

Metabolic responses of postmenopausal women to supplemental dietary boron and aluminum during usual and low magnesium intake: boron, calcium, and magnesium absorption and retention and blood mineral concentrations.

Findings from animal studies indicate that dietary boron affects several aspects of mineral metabolism, especially when animals are subjected to nutritional stressors. Eleven postmenopausal volunteers living on a metabolic ward for 167 d (one 23-d equilibration period and six 24-d treatment periods) were fed a conventional basal diet that supplied a daily average intake of 0.36 mg B, 109 mg Mg, and < 0.10 mg A1/8400 kJ. They were given supplements of 0 (BB) or 3 mg B (SB, last two periods only), 0 (BMg) or 200 mg Mg (SMg) (with magnesium supplements held constant during the last two periods), or 0 (BAl) or 1000 mg A1 (SAl)/d. The SB treatment, compared with the BB treatment, provided a 9.0-fold increase in dietary boron but yielded only a 1.5-fold increase in plasma boron concentrations. Regardless of boron dietary treatment, fecal plus urinary excretion of boron accounted for nearly 100% of dietary boron intake with no evidence of boron accumulation over time. Lack of boron accumulation and relatively small changes in blood boron values during a substantial increase in dietary boron support the concept of boron homeostasis. In subjects fed BMg, SB decreased the percentage of dietary calcium lost in the urine but increased that percentage in volunteers fed SMg, a relation that may be important in understanding metabolic mineral disorders that perturb calcium balance. Reduced calcium absorption during SAl suggests that aluminum supplementation should be limited or at least monitored in postmenopausal women prone to excessive calcium loss. Decreased total urinary oxalate during SB in BMg subjects indicates a possible role for boron in the control of urolithiasis during low-magnesium nutriture.

Aged↗
PubMed1997

Enhancing effect of nickel ions on the response to magnesium ions of single fibers of the frog glossopharyngeal nerve: competitive inhibition by calcium ions of the nickel-enhanced response to magnesium ions.

Single fibers of the frog glossopharyngeal nerve respond to MgCl2 at concentrations exceeding 10 mM. NiCl2 at 1 mM enhanced the Mg2+ response. CaCl2 at 0.5-2 mM induced an inhibition of the Ni(2+)-enhanced response to Mg2+ ions. A quantitative explanation for these results is provided by the hypothesis that Ni2+ ions secondarily affect a magnesium receptor (designated X*Mg) that is responsible for the Mg2+ response and that Ca2+ ions inhibit the Ni(2+)-enhanced response to Mg2+ ions by competing with Mg2+ ions for X*Mg. Double-reciprocal plots of the experimental data indicate that Ni2+ ions do not affect the affinities of X*Mg for both Mg2+ ions (agonist) and Ca2+ ions (competitive antagonist) appreciably, and that Ni2+ ions at 1 mM enhanced the maximal response to Mg2+ ions by 270%. It appears that a magnesium receptor interacts with an Ni(2+)-binding element that is affected by Ni2+ ions and, thus, Ni2+ ions can induce an enhancement of the Mg2+ response.

Animals↗
PubMed2000

Exchangeable magnesium pool masses reflect the magnesium status of rats.

A sensitive and valid marker to assess magnesium (Mg) status in humans is not available. The kinetically determined exchangeable pool masses have been used for other minerals, such as zinc and selenium, as markers of whole-body mineral status. To evaluate the validity of this relationship for Mg, we measured the exchangeable pools of Mg in rats over a range of magnesium dietary intakes. Rats weighing approximately 170 g were fed a control diet (500 mg Mg/kg), a marginally Mg-deficient diet (200 mg/kg) or a severely Mg-deficient diet (60 mg Mg/kg) for 2 wk. Subsequently, rats were administered an intravenous injection of (25)Mg, and the plasma (25)Mg disappearance curve was followed for the next 7 d. The following two methods were employed to analyze the exchangeable pools of Mg: 1) formal compartmental modeling and 2) a simplified determination of the total mass of the rapidly exchangeable Mg pool (EMgP). The mass of the three exchangeable pools (two extracellular pools and one intracellular pool) determined by compartmental analysis decreased in proportion to dietary Mg intake. EMgP, the combined pools of Mg that exchange with the plasma Mg within 48 h, decreased significantly as dietary Mg was lowered. It was positively correlated with conventional markers of Mg status (total Mg in plasma, erythrocyte and tibia Mg levels). Compartmental analysis assesses Mg exchangeable pools more accurately, but determination of EMgP is simpler and faster. Our findings demonstrate that the exchangeable pools of Mg constitute a good marker of Mg status in rats.

Animals↗
PubMed1987

Magnesium, calcium and PTH relationships in dialysis patients after magnesium repletion.

Sixteen end-stage renal disease patients who received hemodialysis for 2.9 years with no magnesium in the dialysate were evaluated for serum calcium, magnesium and parathyroid hormone (PTH) status. Eleven of these patients became hypomagnesemic with subnormal total and ultrafiltrable serum Mg concentrations (low-Mg group). The five remaining patients had consistently normal serum Mg concentrations (normal-Mg group). All had normal total and ionized serum Ca. However, the total and ionized serum Ca levels in the low-Mg group were significantly lower than those of the normal-Mg group. Within 2 weeks of Mg repletion (by dialysis against 0.25 mM of Mg), the N-terminal PTH, total and ultrafiltrable serum Mg, and the total and ionized serum Ca increased in the low-Mg group. There was a strong negative correlation between initial serum Mg and the percent change in N-terminal PTH (r = 0.833) at 2 weeks for all patients. There was also a strong positive correlation between initial ionized Ca and total serum Mg for all patients (r = 0.774). Mg repletion decreased the incidence of cramps experienced during dialysis by all patients. These data suggest that Mg-free dialysis in some patients can cause Mg depletion, which is symptomatic and which may suppress the parathyroid gland.

Adult↗
PubMed1988

Magnesium levels after magnesium-containing cathartics.

To determine the effect on serum Mg++ levels of oral Magnesium-containing cathartics (MgCC) used in the treatment of suspected drug overdose, a prospective, non-randomized study of 24 cases of suspected drug overdose was conducted. Ten cases admitted to the observation unit were assigned to the single dose MgCC group. Fourteen cases admitted to either the ICU or the observation unit were assigned to the multiple dose MgCC group. Single dose cases received 30 gm of magnesium sulfate (MgSO4) at 0 hours. Multiple dose cases received 3 30 gm doses of MgSO4 at 0, 4, and 8 hours. Mg++ levels were measured prior to each MgSO4 dose and 1 and 4 hours after the final dose in both groups. In the single dose group, there was no difference between baseline Mg++ levels and post MgSO4 levels, and only 2/10 developed slightly elevated levels (2.2, 2.3 mEq/L). In the multiple dose group, levels increased and remained significantly higher than baseline after the second MgSO4 dose, and 9/14 developed elevated levels (2.2 to 5.0 mEq/L). All patients who developed elevated Mg++ levels had normal BUN and creatinine values. When the single and multiple dose groups were compared, baseline Mg++ levels were no different (1.68 +/- 0.21 vs 1.69 +/- 0.24, p = 0.952), but peak Mg++ levels were significantly higher in the multiple dose group (1.80 +/- 0.31 vs 2.61 +/- 0.86, p = 0.004). Cases that developed hypermagnesemia had slightly higher baseline Mg++ levels (1.78 +/- 0.22 vs 1.60 +/- 0.19 mEq/L, p = 0.041). In the multiple dose group, higher peak Mg++ levels were noted in cases involving ingestions of anticholinergic or opioid drugs (2.83 vs 1.98, p = 0.025). Hypermagnesemia developed in some cases with normal renal function, blood pressure, and urine output. We conclude that significant hypermagnesemia can occur rapidly after use of multiple dose Mg++ cathartics in standard doses in patients with normal renal function.

Administration, Oral↗
PubMed1982

Physiology of turkey embryos during pipping and hatching. V. Plasma total calcium, magnesium concentrations, and total calcium to magnesium ratios.

Plasma total calcium to magnesium ratios were observed as an index of muscular activity during pipping and hatching of chick and poult embryos. No significant changes were observed in plasma calcium (Ca) or magnesium (Mg) concentrations, but the total Ca to Mg ratio increased significantly just prior to pipping. Lighting the incubator during the last 5 days of incubation in significantly increased plasma Ca and Ca:Mg ratios. Lighting also resulted in significantly better hatchability and less late embryonic mortality. An increased plasma Ca:Mg ratio may be a physiological mechanism to provide increased muscular activity for the embryo in breaking the shell and emerging from it.

Animals↗
PubMed2001

Characteristics of improved NOVA magnesium ion-selective electrode: changes of ionized magnesium values and reference interval in healthy children.

Following the report of interference between the thiocyanate ion (SCN-) and NOVA's previous ion-selective electrode (ISE) for ionized magnesium (iMg2+), NOVA has developed a new ISE which eliminates the effect of SCN-. Two hundred and sixty healthy children were divided into two groups; those who had presented when using NOVA's previous ISE (group A; n = 160) and those using NOVA's new ISE (group B; n = 100). The mean iMg2+ value and the mean iMg2+ percent fraction (iMg2+/serum Mg) were significantly higher in group B than in group A (0.59 +/- 0.03 vs 0.54 +/- 0.03 mmol/L for iMg2+; p < 0.001 and 64.8 +/- 3.1 vs 58.2 +/- 4.1 per cent for iMg2+ percent fraction; p < 0.001). The mean serum SCN- level was 0.023 +/- 0.008 mmol/L in group A (n = 8) and 0.0.21 +/- 0.007 mmol/L in group B (n = 12), and was not significantly different between the two groups. The suspected change of iMg2+ value interfered by SCN- was 0.037 mmol/L in group A. The difference of iMg2+ percent fraction between two groups was higher at high serum magnesium (SMg) levels. The reference interval of iMg2+ was 0.56-0.62 mmo/L in healthy children with the NOVA's new ISE, and was constant irrespective of growth. The NOVA's previous iMg2+ ISE may be interfered with mainly by SCN-. The newly designed ISE eliminated these effects especially at higher SMg levels.

Adolescent↗
PubMed1992

New data on the antiarrhythmic value of parenteral magnesium treatment: magnesium and ventricular arrhythmias.

Antiarrhythmic magnesium (Mg) therapy was evaluated in 20 normomagnesaemic patients affected by ischaemic dilated cardiomyopathy (ID) and severe ventricular arrhythmias, and in 10 patients with torsade de pointes (TdP) occurring in the setting of acquired QT interval prolongation. In the group with IDC, magnesium sulphate was given as slow infusions (50 mg/min over 60 min) twice a day for 7 d. This was antiarrhythmic in all of the patients: ventricular premature contractions and couplets decreased from 13,979 +/- 8964 (mean +/- SD) to 382 +/- 265 (P < 0.001), and from 516 +/- 274 to 9 +/- 6 (P < 0.001), respectively; runs of ventricular tachycardia (41.9 +/- 14.2) disappeared by the fifth day of treatment. The efficacy of antiarrhythmic treatment was evaluated by 24 h Holter monitoring obtained in baseline conditions and after 3, 5 and 10 d from beginning of therapy. In patients with TdP, Mg infusions were instituted at a slow rate (50 mg/min) and continued for 2 h after disappearance of Tdp, which occurred within 20 to 30 min from the start of the Mg infusions. These were followed by prophylactic infusions at rate of 30 mg/min for 90 min twice a day over the next 3 to 4 d. No side effects were observed, and heart rate and QTc remained unchanged from baseline values. In conclusion, Mg infusions may be an effective antiarrhythmic treatment for short and medium-term control of severe ventricular arrhythmias associated with IDC, and may prove useful in the acute treatment of TdP, especially in situations where conventional therapy might prove deleterious or difficult.

Aged↗
PubMed1990

Regulation of potassium and magnesium effluxes by external magnesium in barnacle muscle fibres.

Fluxes and flux rate constants for potassium and magnesium were measured as a function of ambient magnesium concentration in giant muscle fibres from the acorn barnacle. Experiments were carried out in the absence of both external Na and Ca (to prevent possible effects of these ions), and fibres were depleted of internal Na and Ca by soaking in Na- and Ca-free solution before each experiment. K efflux was biphasic with respect to increases in external Mg concentration [( Mg+2]0). K efflux approximately doubled (from about 63 to 130 pmol/cm2.s) when [Mg+2]0 was increased from 2 to 5 mM; K efflux remained elevated in Mg up to 60 mM. However, at [Mg+2]0 = 120 mM, the stimulatory effect of external Mg vanished, and at 357 mM it was replaced by an inhibitory effect. Mg efflux was also biphasic with respect to [Mg+2]0, and this efflux was matched at low to moderate [Mg+2]0 by Mg influx of comparable magnitude. This study suggests the possible existence of a Mg transport system that can serve variously as a Na/Mg or a Mg/Mg exchanger that may require the participation of K ions for its operation.

Animals↗
PubMed1981

[Inhibition of stress reactions by magnesium. Beneficial effects of parenteral magnesium therapy on the development of stress ulcers in rats (author's transl)].

In rats fasted for 24 h with drinking-water ad libitum, gastric ulcers were produced by immobilization for 18 h. Subcutaneous injections of magnesium-aspartate-hydrochloride (Maganesiocard) induced pronounced hypermagnesemia after about 1, 7 and 13 h. Macroscopical estimation of gastric lesions as well as the quantitative microscopical examination performed under blind conditions and considering both surface and depth of the ulcers revealed significant protective effects of the magnesium therapy.

Animals↗
PubMed1996

A comparison of serum magnesium sulfate levels in pregnant women with severe preeclampsia between intravenous and intramuscular magnesium sulfate regimens: a randomized controlled trial.

The frequency of blood samples that achieved therapeutic level was lower in the group of maintenance with intravenous regimen than the intramuscular regimen significantly at 15, 30, 60, 120 and 240 minutes after loading dose. The mean level of serum magnesium sulfate in the intravenous group was significantly lower than intramuscular group. This study supported to choose the maintenance by intramuscular regimen. However, further study is required to analyse the effect of higher level of magnesium sulfate in Thai patients.

Adult↗
PubMed1998

Contribution to interaction between magnesium and toxic metals: the effect of prolonged cadmium intoxication on magnesium metabolism in rabbits.

The results obtained up to now indicate that increased intake of some heavy metals causes disorder of bioelements metabolism leading to their blood and organs decrease and higher elimination via the urine. As to lead and magnesium, our investigations indicated that the reaction is reversible and that increased intake of Mg eliminates Pb via urine. Some other findings suggest similar relations between Mg and certain heavy metals, thus pointing to significant role of Mg in toxicology of heavy metals and announcing a new chapter in the toxicology of metals entitled 'Mg in professional and ecotoxicology'. In this report we present the results of our investigations on the effect of Cd on Mg metabolism. The experiment was performed on rabbits given orally, every day, for 4 weeks 10 mg Cd/kg b.w. as aqueous solution of CdCl2. Magnesium content was determined in blood, urine, soft tissues and bones by the AAS method. Under the experimental conditions, Cd lead to statistically significant decrease of blood Mg (p < 0.001 after day 16) which was associated with increased Mg elimination via urine (p < 0.01). Statistically significant changes were not detected in the tissues, except in the liver where we found enhanced Mg content (p < 0.05), while its level in the muscles decreased (p < 0.01).

Animals↗
PubMed1984

Changes in plasma, red blood cell and cerebrospinal fluid mineral concentrations in calves during magnesium depletion followed by repletion with rectally infused magnesium chloride.

Hypomagnesemic and normomagnesemic calves were infused rectally with MgCl2 X 6H2O to determine effects on magnesium (Mg), calcium (Ca) and potassium (K) concentrations in plasma, red blood cells (RBC) and cerebrospinal fluid (CSF). Sixteen Holstein bull calves were fed one of four semipurified diets containing low or adequate Mg and normal or excess K in a 2 X 2 factorial arrangement. When CSF Mg concentration began to decrease in calves fed low Mg diets, each calf was given a rectal infusion of 50 ml of 30% MgCl2 X 6H2O solution while under general anesthesia. Blood and CSF were then sampled periodically for 3 hours and plasma, RBC and CSF were analyzed for Mg, Ca and K concentration. Plasma Mg increased (P less than 0.001) within 5 minutes after rectal infusion in all calves regardless of diet. An increase (P less than 0.01) in CSF Mg was also observed within 30 minutes in hypomagnesemic calves with CSF Mg levels less than 1.8 mg/dl. Rectal infusions had no effect on K in plasma, Ca or K in CSF, Mg, Ca or K in RBC, or packed cell volume but plasma Ca had increased (P less than 0.05) within 120 minutes in calves fed low Mg and high K and within 60 minutes in those fed adequate Mg, normal K diets.

Animals↗
PubMed1980

Comparative plasma salicylate and urine salicylurate levels following administration of aspirin, magnesium salicylate, and choline magnesium trisalicylate.

Eighteen healthy volunteers were administered single doses of commercially available solid dosage forms of aspirin, magnesium salicylate (I), and choline magnesium trisalicylate (II), equivalent to approximately 500 mg of salicylic acid, in a randomized, complete crossover design. Plasma salicylate and urine salicylurate levels were measured by high-pressure liquid chromatography at frequent intervals following dosing; the resultant profiles, areas under the curve (AUC), and percentages of dose excreted as salicylurate were statistically analyzed by an analysis of variance. The plasma salicylate levels following the two dosage forms containing I and II were virtually identical when corrected for small differences in the dose. The plasma salicylic acid level following aspirin was approximately 10% lower during the 1.5--3.0-hr interval due to a portion of unhydrolyzed aspirin, but the dose-corrected AUC for the products tested did not differ significantly (p < 0.05). During the 24 hr following dosing, 66.5 +/- 12.1 68.4 +/- 7.1, and 60.9 +/- 14.1% of the salicylic acid were excreted as urine salicylurate for aspirin, I, and II, respectively, with no significant difference (p < 0.05). Based on this study, there are no significant differences in the rate and extent of absorption of salicylate following the three dosage forms tested, and the elimination kinetics of salicylic acid are not altered by these dosage forms.

Adolescent↗
PubMed2006

Solid-state 25Mg NMR spectroscopic and computational studies of organic compounds. square-pyramidal magnesium(II) ions in aqua(magnesium) phthalocyanine and chlorophyll a.

We report a solid-state (25)Mg NMR spectroscopic study of two magnesium-containing organic compounds: monopyridinated aqua(magnesium) phthalocyanine (MgPc.H(2)O.Py) and chlorophyll a (Chla). Each of these compounds contains a Mg(II) ion coordinating to four nitrogen atoms and a water molecule in a square-pyramidal geometry. Solid-state (25)Mg NMR spectra for MgPc.H(2)O.Py were obtained at 11.7 T (500 MHz for (1)H) for a (25)Mg-enriched sample (99.1% (25)Mg atom) using both Hahn-echo and quadrupole Carr-Purcell Meiboom-Gill (QCPMG) pulse sequences. Solid-state (25)Mg NMR spectra for Chla were recorded at (25)Mg natural abundance (10.1%) at 19.6 T (830 MHz for (1)H). The (25)Mg quadrupole parameters were determined from spectral analyses: MgPc.H(2)O.Py, C(Q) = 13.0 +/- 0.1 MHz and eta(Q) = 0.00 +/- 0.05; Chla, C(Q) = 12.9 +/- 0.1 MHz and eta(Q) = 1.00 +/- 0.05. This work represents the first time that Mg(II) ions in a square-pyramidal geometry have been characterized by solid-state (25)Mg NMR spectroscopy. Extensive quantum mechanical calculations for electric-field-gradient (EFG) and chemical shielding tensors were performed at restricted Hartee-Fock (RHF), density functional theory (DFT), and second-order Møller-Plesset perturbation theory (MP2) levels for both compounds. Computed (25)Mg nuclear quadrupole coupling constants at the RHF and MP2 levels show a reasonable basis-set convergence at the cc-pV5Z basis set (within 7% of the experimental value); however, B3LYP results display a drastic divergence beyond the cc-pVTZ basis set. A new crystal structure for MgPc.H(2)O.Py is also reported.

Journal Article↗