Neurobehavioral and biochemical effects of magnesium chloride (MgCl2), magnesium sulphate (MgSO4) and magnesium-L-threonate (MgT) supplementation in rats: A dose dependent comparative study

Magnesium (Mg) is an essential biomineral that acts as an intracellular cofactor for more than 300 enzymes. It is an important modulator of the N-methyl-D-aspartate (NMDA) receptor which is involved in memory function and depression. The purpose of this study was to compare the dose dependent effect of oral supplementation of Magnesium chloride (MgCl₂), Magnesium sulphate (MgSO₄) and Magnesium-L-threonate (MgT) on memory and depression-related behaviors in rats. Rats were orally administered with different doses (50 mg/kg, 100 mg/kg and 150 mg/kg) of each Mg salt. Following 28 days of oral supplementation, animals were subjected to behavioral tests. After completion of behavioral test, rats were decapitated. Brain and plasma samples were used for neurochemical and biochemical analysis. Assessment of behaviors in elevated plus maze (EPM) test and forced swim test (FST) showed that MgT more significantly improved memory of rats and decreased depression-like symptoms in healthy rats as compared to controls. Biochemical analysis indicated significant increase in plasma Mg levels dose dependently following MgT administration. This increase might be related to observe enhanced cholinergic functions and decline in oxidative stress in rats in the present study. This comparative study highlights that MgT (100mg/kg) is the most appropriate Mg salt and dose for oral treatment that strengthens cholinergic system and improves brain related functions through attenuation of oxidative burden in adult healthy rats.

Sodium reduction during cardiopulmonary bypass: Plasma-Lyte 148 versus trial fluid as pump primes

OBJECTIVES

We compared effects on plasma sodium concentrations plus calculated plasma tonicity of two "balanced" crystalloid solutions used as 2 L pump primes during cardiopulmonary bypass (CPB): Plasma-Lyte 148 (sodium concentration, 140 mmol/L; potassium concentration, 5 mmol/L) versus a bicarbonate-balanced fluid (sodium concentration, 140 mmol/L; potassium concentration, 0 mmol/L).

DESIGN, SETTING AND PARTICIPANTS

We analysed pooled data from two prospective interventional studies performed in university-affiliated hospitals, from 50 patients undergoing elective cardiac surgery.

INTERVENTIONS

Participants were allocated equally to Plasma-Lyte 148 or bicarbonate-balanced fluid, with plasma electrolytes measured by direct ion selective electrodes immediately before bypass (pre-CPB), within 3 minutes of commencement (T2), and before bypass cessation (end-CPB).

RESULTS

Plasma sodium fell at T2 in 46 patients (92%) (P<0.0005). With Plasma-Lyte 148, the mean sodium decreased by 3.0 mmol/L (SD, 1.7 mmol/L), and with bicarbonate-balanced fluid it decreased by 2.2 mmol/L (SD, 1.1 mmol/L) (P=0.002). The mean tonicity fell by >5 mOsm/kg for both groups (P<0.0005). At end-CPB, the mean sodium for both groups remained reduced by >2 mmol/L (P<0.0005). In the group receiving Plasma-Lyte 148, 52% of patients were hyponatraemic (sodium<135 mmol/L) at T2 and end-CPB.

CONCLUSIONS

Sodium reductions were common with both priming solutions, but more severe with Plasma-Lyte 148. Crystalloid priming solutions require sodium concentrations>140mmol/L to ensure normonatraemia throughout CPB.

Effects of transdermal magnesium chloride on quality of life for patients with fibromyalgia: a feasibility study

BACKGROUND

Fibromyalgia is a syndrome characterized by chronic pain, fatigue, depression, and sleep disturbances. Its primary cause is unclear. Several studies have reported decreased intracellular magnesium levels in patients with fibromyalgia and have found negative correlation between magnesium levels and fibromyalgia symptoms.

OBJECTIVE

To gather preliminary data on whether transdermal magnesium can improve quality of life for women who have fibromyalgia.

DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS

This is a patient questionnaires and survey in a fibromyalgia clinic at a tertiary medical center. Forty female patients with the diagnosis of fibromyalgia were enrolled. Each participant was provided a spray bottle containing a transdermal magnesium chloride solution and asked to apply 4 sprays per limb twice daily for 4 weeks. Participants were asked to complete the Revised Fibromyalgia Impact Questionnaire, SF-36v2 Health Survey, and a quality-of-life analog scale at baseline, week 2, and week 4.

MAIN OUTCOME MEASURE

Questionnaire and survey scores, evaluated through intent-to-treat and per-protocol analyses.

RESULTS

Twenty-four patients completed the study (mean [SD] age, 57.2 [7.6] years; white, 95%; mean body mass index, 31.3 kg/m2). With intention-to-treat analysis, Revised Fibromyalgia Impact Questionnaire subscale and total scores were significantly improved at week 2 and week 4 (total score, P=0.001). Per-protocol analysis results were similar: all subscales of the Revised Fibromyalgia Impact Questionnaire were significantly improved at week 2 and week 4 (total score, P=0.001).

CONCLUSION

This pilot study suggests that transdermal magnesium chloride applied on upper and lower limbs may be beneficial to patients with fibromyalgia.

TRIAL REGISTRATION

ClinicalTrials.gov.ldentifier NCT01968772.

A Combination of Intravenous Genistein Plus Mg2+ Enhances Antihypertensive Effects in SHR by Endothelial Protection and BKCa Channel Inhibition

BACKGROUND

The effects of combining genistein (GST) plus magnesium (Mg) upon the development of hypertension were examined in 28 twelve-week-old male spontaneous hypertension rats (SHRs). Four experimental groups were tested: SHR (0.9% NaCl and DMSO), SHR + GST (0.9% NaCl and GST 5mg/kg/day), SHR + Mg (Mg(2+) 0.75 mmol/kg/day and DMSO), and SHR + GST + Mg (Mg(2+) 0.75 mmol/kg/day and GST 5mg/kg/day). A group of normotensive genetic control, Wistar-Kyoto (WKY) rats were also included for comparison. Drugs were administrated intravenously daily for 30 days.

METHODS

Systolic blood pressure (SBP) and heart rate were measured by tail-cuff plethysmography every five days. Vascular tone of mesenteric arteries was examined by an isometric force transducer. Big-conductance calcium-activated potassium channel (BKCa) currents were detected by whole-cell patch-clamp techniques.

RESULTS

SBP in SHRs was significantly elevated vs. that in WKY rats. GST or Mg lowered SBP of SHRs. Their combination enhanced antihypertensive effects, as indicated by significantly lowered SBP and shorter onset times. GST or Mg individually improved endothelial dysfunction of SHRs. However, again their combination enhanced endothelial protection, nearly restoring maximal relaxation responses to those seen in WKY. BKCa currents in SHRs were increased compared with WKY rats. GST, Mg, and their combination restored BKCa currents to those of WKY rats.

CONCLUSIONS

The combination of GST and Mg produces antihypertensive effects and improvement of endothelial dysfunction, which are substantially greater than that when either is used individually. These results suggest a novel and feasible protocol for the prevention and treatment of hypertension and related cardio- and cerebro-vascular diseases.

Overview of the study protocols and statistical analysis plan for the Saline versus Plasma-Lyte 148 for Intravenous Fluid Therapy (SPLIT) research program

BACKGROUND

0.9% saline is the most commonly used intravenous (IV) fluid in the world but recent data raise the possibility that, compared with buffered crystalloid fluids such as Plasma-Lyte 148, the administration of 0.9% saline might increase the risk of developing acute kidney injury.

OBJECTIVE

To provide an overview of the study protocols and statistical analysis plan for the six studies making up the (0.9% Saline v Plasma-Lyte 148 for Intravenous Fluid Therapy (SPLIT) research program.

METHODS

The SPLIT study consists of six integrated clinical trials, including a double-blind, cluster, randomised, double-crossover study in intensive care unit patients, incorporating two nested studies within it; an open-label, before-and-after study in emergency department (ED) patients; a single-centre, double-blind, crossover trial in major surgical patients; and a randomised, double-blind study in ICU patients. All studies focus on biochemical and renal outcomes but will also provide preliminary data on patient-centred outcomes including inhospital mortality and requirements for dialysis.

RESULTS AND CONCLUSION

The SPLIT study program will provide preliminary data on the comparative effectiveness of using 0.9% saline v Plasma-Lyte 148 for IV fluid therapy in ED, surgical and ICU patients.

Using a low-sodium, high-potassium salt substitute to reduce blood pressure among Tibetans with high blood pressure: a patient-blinded randomized controlled trial

Objectives

To evaluate the effects of a low-sodium and high-potassium salt-substitute on lowering blood pressure (BP) among Tibetans living at high altitude (4300 meters).

Method

The study was a patient-blinded randomized controlled trial conducted between February and May 2009 in Dangxiong County, Tibetan Autonomous Region, China. A total of 282 Tibetans aged 40 or older with known hypertension (systolic BP≥140 mmHg) were recruited and randomized to intervention (salt-substitute, 65% sodium chloride, 25% potassium chloride and 10% magnesium sulfate) or control (100% sodium chloride) in a 1: 1 allocation ratio with three months’ supply. Primary outcome was defined as the change in BP levels measured from baseline to followed-up with an automated sphygmomanometer. Per protocol (PP) and intention to treat (ITT) analyses were conducted.

Results

After the three months’ intervention period, the net reduction in SBP/DBP in the intervention group in comparison to the control group was −8.2/−3.4 mmHg (all p<0.05) in PP analysis, after adjusting for baseline BP and other variables. ITT analysis showed the net reduction in SBP/DBP at −7.6/−3.5 mmHg with multiple imputations (all p<0.05). Furthermore, the whole distribution of blood pressure showed an overall decline in SBP/DBP and the proportion of patients with BP under control (SBP/DBP<140 mmHg) was significantly higher in salt-substitute group in comparison to the regular salt group (19.2% vs. 8.8%, p = 0.027).

Conclusion

Low sodium high potassium salt-substitute is effective in lowering both systolic and diastolic blood pressure and offers a simple, low-cost approach for hypertension control among Tibetans in China.

Trial Registration

ClinicalTrials.gov NCT01429246

[Correction of isoproterenol-induced myocardial injury with magnesium salts in magnesium-deficient rats]

The effect of Mg L-asparaginate (Mg-L-Asp), Mg chloride (MgCl2) and Mg sulfate (MgSO4) on the severity of isoproterenol-induced myocardial injury in Mg-deficient rats has been evaluated. To induce Mg deficiency, twenty-eight rats were placed on a low Mg diet (Mg content < 15 mg/kg) and demineralized water for 10 weeks. Twelve control rats were fed a basal control diet (Mg content = 500 mg/kg) and water (with Mg content 20 mg/l) for equal duration. On day 49 of low Mg diet, Mg-deficient rats were randomly divided into four groups: 1) group that continued to receive low Mg diet; 2) low Mg diet plus oral MgSO4; 3) low Mg diet plus oral Mg-L-Asp and 4) low Mg diet plus oral MgCl2 (50 mg of Mg per kg of body weight). Isoproterenol was injected subcutaneously (30 mg/kg BW, twice, at an interval of 24 hours) on the day 70 of the study, when plasma and erythrocyte Mg level in rats fed a low Mg diet were significantly decreased by 47% and 45% compared to intact animals. Twenty-four hours after second injection of isoproterenol, tests for activities of creatine kinase (CK), lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) were run and histopathological study was carried out. Administration of isoproterenol to rats resulted in significantly elevated plasma CK, LDH and AST, however analyses in Mg deficient group demonstrated more dramatically increased activity of CK and AST compared to control rats (3,06 and 4,67 fold in Mg-deficient group vs. 1,91 and 3,92 fold in intact group). Increased leakage of cardiac injury markers was concomitant to increased volume of fuchsinophilic cardiomyocytes (54.2 +/- 1.7% in Mg-deficient group and 38.9 +/- 1.9% in intact group, p < 0.05). However, pretreatment with of MgCl2, MgSO4 and Mg-L-Asp during 21 days favorably decreased sensitivity of myocardium to isoproterenol-induced ischemic injury. All evaluated salts significantly decreased myocyte marker enzymes as well as protected myocardium against isoproterenol-induced histopathological perturbations.

Oral magnesium supplementation reduces insulin resistance in non-diabetic subjects - a double-blind, placebo-controlled, randomized trial

The incidence of insulin resistance and metabolic syndrome correlates with the availability of magnesium (Mg). We studied the effect of oral Mg supplementation on insulin sensitivity and other characteristics of the metabolic syndrome in normomagnesemic, overweight, insulin resistant, non-diabetic subjects. Subjects were tested for eligibility using oral glucose tolerance test (OGTT) and subsequently randomized to receive either Mg-aspartate-hydrochloride (n = 27) or placebo (n = 25) for 6 months. As trial endpoints, several indices of insulin sensitivity, plasma glucose, serum insulin, blood pressure and lipid profile were determined. Mg supplementation resulted in a significant improvement of fasting plasma glucose and some insulin sensitivity indices (ISIs) compared to placebo. Blood pressure and lipid profile did not show significant changes. The results provide significant evidence that oral Mg supplementation improves insulin sensitivity even in normomagnesemic, overweight, non-diabetic subjects emphasizing the need for an early optimization of Mg status to prevent insulin resistance and subsequently type 2 diabetes.

Controlled hyperkalemic reperfusion with magnesium rescues ischemic juvenile hearts by reducing calcium loading

OBJECTIVES

Our objectives were (1) to determine whether elevated Mg(2+) in controlled hyperkalemic reperfusate without intervention during ischemia protects the juvenile heart against reperfusion injury; and (2) to identify the mechanism(s) underlying any protective effect of Mg(2+).

METHODS

Langendorff-perfused hearts from juvenile (11- to 14-day-old) guinea pigs were subjected to mild (30-minute) or severe (45-minute) normothermic global ischemia and 35-minute reperfusion. Hearts were subjected to controlled hyperkalemic reperfusion without or with various concentrations of Mg(2+) (5, 10, 16, 23 mM). The mechanisms underlying the effect of Mg(2+) on intracellular Ca(2+) ([Ca(2+)]i) were also studied in isolated cardiomyocytes exposed to metabolic inhibition followed by washout using hyperkalemic solutions (reperfusion).

RESULTS

Sixteen mM Mg(2+) conferred maximal cardioprotection as assessed by improved functional recovery and reduced cardiac injury; this was associated with a significant recovery of cardiac energetics and metabolism following both mild and severe ischemia. The Mg(2+)-induced protection was additive to that of hyperkalemia following mild ischemia and conferred protection following severe ischemia when hyperkalemia alone had no significant effect. Elevated Mg(2+) in the hyperkalemic reperfusate of cardiomyocytes acutely prevented [Ca(2+)]i loading following mild metabolic inhibition and augmented the fall in [Ca(2+)]i following severe metabolic inhibition.

CONCLUSIONS

This work demonstrates for the first time in juvenile hearts that elevated Mg(2+) during controlled hyperkalemic reperfusion rescues the heart following ischemia, and that this is likely to be facilitated by reducing [Ca(2+)]i which, in turn, would aid metabolic recovery.

Pretreatment effect of magnesium on alloxan induced hyperglycemia in rats

The role of vitamins and mineral supplementation in the management of Diabetes mellitus is not well elucidated. We therefore carried out a preliminary study to assess the effect of prior administration of Magnesium on induction of alloxan diabetes, a model of type 1 diabetes mellitus. Twenty Male albino rats were used for this study. The animals were divided into 4 groups of 5 animals each. Animals in group 1 were normal rats and were not given any treatment, these served as healthy control. Animals in group 2 were diabetic rats that were not given any treatment, they served as diabetic control. Animals in group 3 were treated with magnesium (100mg/kg) intraperitoneally one hour prior to alloxan (150mg/kg) administration. Animals in group 4 were given intraperitoneal injection of magnesium (100mg/kg) once, and blood samples were obtained one hour after administration. Blood samples were obtained from all animals after 48 hours and plasma glucose levels determined using the glucose oxidase method. There was significant increase (p<0.001) in plasma glucose level in the alloxan treated group when compared with the control. There was also a significant increase (p<0.01) in magnesium-pretreated diabetic group. However, there was a significant reduction (p<0.01) in blood glucose level 48 hours after alloxan administration in the magnesium pre-treated diabetic group when compared with the diabetic controls. Magnesium pretreatment may delay the onset of alloxan induced hyperglycemia and this may be due to the scavenging effect of magnesium on the highly reactive hydroxyl radicals (OH) which was generated through alloxan reaction.

Utilization of magnesium during hypokinesia and magnesium supplementation in healthy subjects

OBJECTIVE

The incompleteness of electrolyte utilization during hypokinesia and electrolyte supplementation is the defining factor of electrolyte metabolic changes, yet the effect of electrolyte supplementation and HK upon electrolyte utilization is poorly understood. To determine the influence of magnesium (Mg(2+)) supplementation and hypokinesia (diminished movement) on magnesium utilization, we investigated the use of Mg(2+) supplementation to establish its effect upon muscle Mg(2+) content and Mg2(2+) losses.

METHODS

This study was conducted in 40 physically healthy male volunteers during a pre-experimental period of 30 d and an experimental period of 364 d. Subjects were equally divided into four groups: unsupplemented control subjects (UCSs), unsupplemented experimental subjects (UESs), supplemented control subjects (SCSs), and supplemented experimental subjects (SESs). A daily supplementation of 3.0 mmol of magnesium-chloride per kilogram of body weight was given to subjects in the SCS and SES groups.

RESULTS

Muscle Mg(2+) content decreased (P < 0.05) and plasma Mg(2+) concentration and Mg(2+) loss in urine and feces increased (P < 0.05) in the SES and UES groups compared with their pre-experimental levels and values in their respective control groups (SCS and UCS). Muscle Mg(2+) content decreased more (P < 0.05) and plasma Mg(2+) concentration and Mg(2+) loss in urine and feces increased more (P < 0.05) in the SES group than in the UES group.The muscle Mg(2+) content and plasma Mg(2+) level and Mg(2+) losses did not change in the control groups.

CONCLUSION

Daily Mg(2+) supplementation during prolonged hypokinesia decreases more muscle Mg(2+) content and Mg(2+)-deficient muscle increases more Mg(2+) loss in healthy subjects indicating lower Mg(2+) utilization with than without Mg(2+) supplementation.

[Comparative study of magnesium salts bioavailability in rats fed a magnesium-deficient diet]

The purpose of this study was to compare efficiency of compensation of alimentary Mg deficiency after administration of 12 organic and 8 inorganic magnesium salts and to evaluate the ability of vitamin B6 to accelerate their effect. Two hundred eighty rats were placed on a Mg-deficient diet (Mg content (15 mg/kg) and demineralized water for 7 weeks. Twelve control rats were fed a basal diet (Mg content 500 mg/kg). Starting from day 49 of the Mg-deficient diet, the rats were given magnesium salts (50 mg magnesium and 5 mg pyridoxine per kg): Mg chloride, Mg sulphate, Mg oxide, M nitrate, Mg thiosulphate, Mg hydrophosphate, Mg carbonate, Mg trisilicate, Mg (L-, D- and DL-) aspartate, Mg (L- and DL-) pyroglutamate, Mg succinate, Mg glycinate, Mg orotate, Mg taurate, Mg lactate or their combination with vitamin B6 (5 mg/kg b.w.). Erythrocyte and plasma Mg levels were measured by spectrophotometry following the colour reaction between Mg and titanium yellow. Mg L-aspartate compensated for magnesium deficit more effectively and faster than all other salts. Mg chloride showed the highest efficiency among inorganic magnesium salts. Both Mg chloride and Mg L-aspartate in combination with vitamin B6 caused statistically significant compensation of magnesium deficit.

[Effect of bischofit mineral ointment on the allergic contact dermatitis caused by 2,4-dinitrochlorobenzene]

Bischofit-based ointment is shown to have a beneficial effect on the course of model contact dermatitis caused by 2,4-dinitrochlorobenzene.

[Effects of mangesium salts and their combinations with vitamin B6 on oxalates crystalluria in rats fed with pyridoxine-deficient diet]

We studied the effects of oral magnesium (Mg) salts either alone or in combination with pyridoxine hydrochloride in rats on pyridoxine-deficient diet. Fifty-four male rats were randomized into two groups and were fed either a standard diet or a pyridoxine-deficient diet for 3 weeks. A significant rise of the EGOT index ( > 1.5), oxaluria (from 74.8 +/- 5.2 to 117.9 +/- 12.3 mcM/l, p = 0.035), and crystalluria in rats fed with pyridoxine deficient diet were revealed. Oral Mg chloride, Mg L-aspartate either alone or in combination with pyridoxine in comparison with magnesium sulfate, magne B6 (Mg lactate with pyridoxine) and pyridoxine alone were administered (50 mg of magnesium and/or 5 mg of pyridoxine per kg body weight). Magnesium salts in combination with pyridoxine lowered an oxalate level and crystalluria whereas magnesium salts alone reduced only crystalluria. Antilithis effects of Mg L-aspartate and Mg chloride in combination with pyridoxine were comparable with those observed in magne B6 or pyridoxine treatment and were significantly higher than in magnesium sulfate treatment.

Efficacy and safety of oral magnesium supplementation in the treatment of depression in the elderly with type 2 diabetes: a randomized, equivalent trial

To evaluate the efficacy and safety of oral magnesium supplementation, with magnesium chloride (MgCl2), in the treatment of newly diagnosed depression in the elderly with type 2 diabetes and hypomagnesemia. Twenty-three elderly patients with type 2 diabetes and hypomagnesemia were enrolled and randomly allocated to receive either 50 mL of MgCl2 5% solution equivalent to 450 mg of elemental magnesium or Imipramine 50 mg daily during 12 weeks. Widowhood or divorce in the last six months, alcoholism, degenerative illnesses of the nervous central system, recent diagnosis of diabetes, previous or current treatment with antidepressants, chronic diarrhea, use of diuretics, and reduced renal function were exclusion criteria. Hypomagnesemia was defined by serum magnesium levels < 1.8 mg/dL and depression by Yasavage and Brink score > or = 11 points. The primary trial end point was the improvement of depression symptoms. At baseline, there were no differences by age (69 +/- 5.9 and 66.4 +/- 6.1 years, p = 0.39), duration of diabetes (11.8 +/- 7.9 and 8.6 +/- 5.7 years, p = 0.33), serum magnesium levels (1.3 +/- 0.04 and 1.4 +/- 0.04 mg/dL, p = 0.09), and Yasavage and Brink Score (17.9 +/- 3.9 and 16.1 +/- 4.5 point, p = 0.34) in the groups with MgCl2 and imipramine, respectively. At end of follow-up, there were no significant differences in the Yasavage and Brink score (11.4 +/- 3.8 and 10.9 +/- 4.3, p = 0.27) between the groups in study; whereas serum magnesium levels were significantly higher in the group with MgCl2 (2.1 +/- 0.08 mg/dL) than in the subjects with imipramine (1.5 +/- 0.07 mg/dL), p < 0.0005. In conclusion, MgCl2 is as effective in the treatment of depressed elderly type 2 diabetics with hypomagnesemia as imipramine 50 mg daily.

[Regenerating activity of hydrophilic bischofit mineral ointment in the treatment of acute local cryotrauma]

A stimulatory effect of hydrophilic bischofit mineral ointment on the processes of skin regeneration after acute local cryotrauma is demonstrated.

Expression of cytochrome P450 aromatase transcripts in buffalo (Bubalus bubalis)-ejaculated spermatozoa and its relationship with sperm motility

The cytochrome P450 aromatase (aromP450) deficient mice are infertile due to an impairment of spermatogenesis associated with a decrease in sperm motility and inability to fertilize oocytes. The sperm analysis showed decreased sperm motility in humans, having Cyp19 gene mutations. Further, in human, it was hypothesized that aromatase could be used as marker of sperm quality, particularly in the acquisition of its motility. However, there is no information regarding the expression of aromP450 in spermatozoa of farm animals including cattle and buffalo. In the present study, the expression of aromP450 in ejaculated buffalo spermatozoa and its relationship with sperm motility of ejaculated spermatozoa was studied by RT-PCR using total RNA isolated from buffalo-ejaculated spermatozoa. The results showed that conventional RT-PCR could not amplify aromatase transcript, while a nested PCR detected the presence of P450arom mRNA in buffalo-ejaculated spermatozoa. RT reaction followed by nested PCR was performed to compare the expression of aromatase transcripts in buffalo-ejaculated spermatozoa of two category semen graded on the basis of mass motility and motile and non-motile spermatozoa separated by swim-up. A higher (P<0.01) expression of aromP450 transcript was found in spermatozoa obtained from the good quality semen (higher mass motility) to that in spermatozoa of poor quality semen (low mass motility). Similarly, higher (P<0.01) expression of aromP450 mRNA was observed in the motile spermatozoa as compared to non-motile spermatozoa separated from good quality semen by swim-up. It is concluded that the present study demonstrates a positive relation between aromatase transcript and mass motility of buffalo-ejaculated spermatozoa, which could be a putative marker for the quality of semen in farm animals, particularly the acquisition of sperm motility.

Intravenous magnesium for acute myocardial infarction

BACKGROUND

Mortality and morbidity from acute myocardial infarction (AMI) remain high. Intravenous magnesium started early after the onset of AMI is thought to be a promising adjuvant treatment. Conflicting results from earlier trials and meta-analyses warrant a systematic review of available evidence.

OBJECTIVES

To examine the effect of intravenous magnesium versus placebo on early mortality and morbidity.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library Issue 3, 2006), MEDLINE (January 1966 to June 2006) and EMBASE (January 1980 to June 2006), and the Chinese Biomedical Disk (CBM disk) (January 1978 to June 2006). Some core Chinese medical journals relevant to the cardiovascular field were hand searched from their starting date to the first-half year of 2006.

SELECTION CRITERIA

All randomized controlled trials that compared intravenous magnesium with placebo in the presence or absence of fibrinolytic therapy in addition to routine treatment were eligible if they reported mortality and morbidity within 35 days of AMI onset.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed the trial quality and extracted data using a standard form. Odds ratio (OR) were used to pool the effect if appropriate. Where heterogeneity of effects was found, clinical and methodological sources of this were explored.

MAIN RESULTS

For early mortality where there was evidence of heterogeneity, a fixed-effect meta-analysis showed no difference between magnesium and placebo groups (OR 0.99, 95%CI 0.94 to 1.04), while a random-effects meta-analysis showed a significant reduction comparing magnesium with placebo (OR 0.66, 95% CI 0.53 to 0.82). Stratification by timing of treatment (< 6 hrs, 6+ hrs) reduced heterogeneity, and in both fixed-effect and random-effects models no significant effect of magnesium was found. In stratified analyses, early mortality was reduced for patients not treated with thrombolysis (OR=0.73, 95% CI 0.56 to 0.94 by random-effects model) and for those treated with less than 75 mmol of magnesium (OR=0.59, 95% CI 0.49 to 0.70) in the magnesium compared with placebo groups.Meta-analysis for the secondary outcomes where there was no evidence of heterogeneity showed reductions in the odds of ventricular fibrillation (OR=0.88, 95% CI 0.81 to 0.96), but increases in the odds of profound hypotension (OR=1.13, 95% CI 1.09 to 1.19) and bradycardia (OR=1.49, 95% CI 1.26 to 1.77) comparing magnesium with placebo. No difference was observed for heart block (OR=1.05, 95% CI 0.97-1.14). For those outcomes where there was evidence of heterogeneity, meta-analysis with both fixed-effect and random-effects models showed that magnesium could decrease ventricular tachycardia (OR=0.45, 95% CI 0.31 to 0.66 by fixed-effect model; OR=0.40, 95% CI 0.19 to 0.84 by random-effects model) and severe arrhythmia needing treatment or Lown 2-5 (OR=0.72, 95% CI 0.60 to 0.85 by fixed-effect model; OR=0.51, 95% CI 0.33 to 0.79 by random-effects model) compared with placebo. There was no difference on the effect of cardiogenic shock between the two groups.

AUTHORS' CONCLUSIONS

Owing to the likelihood of publication bias and marked heterogeneity of treatment effects, it is essential that the findings are interpreted cautiously. From the evidence reviewed here, we consider that: (1) it is unlikely that magnesium is beneficial in reducing mortality both in patients treated early and in patients treated late, and in patients already receiving thrombolytic therapy; (2) it is unlikely that magnesium will reduce mortality when used at high dose (>=75 mmol); (3) magnesium treatment may reduce the incidence of ventricular fibrillation, ventricular tachycardia, severe arrhythmia needing treatment or Lown 2-5, but it may increase the incidence of profound hypotension, bradycardia and flushing; and (4) the areas of uncertainty regarding the effect of magnesium on mortality remain the effect of low dose treatment (< 75 mmol) and in patients not treated with thrombolysis.

[Can modern infusion solutions cause serious disruption of inner environment of an organism?]

The article brings a description of a patient case when an application of mineral balanced infusion solutions led to a disruption of inner environment, beginning of a combined failure of the acid-base balance with a serious metabolic acidosis. Patient J. was artificially respirated after a CPR. During the therapy the patient was given basically without any changes a combination of mineral solution Plasma-Lyte 148, amino-acid and 20% glucose. During 8 days a serious metabolic alkalosis had developed (caused by a lack of chlorides, phosphates and other reasons), combined with respirational acidosis. Hydrogencarbonate level was increased to 47.2 mmo/l (at norm of 24 mmol/l), base excess level to 21.4 mmol/l (at norm of 0 mmol/l). Metabolic acidosis led to reduction of sensibility of the respiratory centers and therefore it was not possible to restore spontaneous respiration. After the therapy change and reduction of metabolic acidosis the state of the patient got better. Application of acidifying solutions, supplementation of phosphate and potassium levels and replenishment of actual losses of phosphates led to regulation of the inner environment. Together with the application of sufficient amount of basic nutrients was the improvement of acid-base balance the key factor which enabled the restoration of spontaneous respiration and disconnection of the patient from the ventilator. In short summary you can see reasons which cause different effect of identical infusions to acid-base balance of the inmates in different situations. The article points to a necessity of controlling groovy medical procedures according to actual patient's needs.

Effect of a metabolically created systemic acidosis on calcium homeostasis and the diurnal variation in urine pH in the non-lactating pregnant dairy cow

Reducing the dietary cation-anion difference (DCAD) has been shown to be an effective means of preventing parturient paresis in confinement systems where cows are offered a total mixed ration containing DCAD-reducing mineral compounds (anionic salts). Such a supplementation strategy is not possible in cows being group fed forages precalving, and little is known about the effect of supplementing these cows with large amounts of anionic salts twice daily.

Eight non-lactating, pregnant Holstein-Friesian cows were allocated to two levels of DCAD (−20 and +18 meq/100 g DM) for 24 d, with an intensive Ca balance undertaken in metabolism stalls following a 2-week acclimatization to diet. The basal diet was 3 kg DM of crushed barley and 7 kg DM of pasture-hay. Urine and faeces were collected separately, weighed daily for 5 d and analysed for Ca content. Urinary Ca, creatinine and hydroxyproline concentration and plasma Ca concentration were determined during the period of the balance study. The diurnal pattern in urine and rumen pH was determined over 2 d. Decreasing DCAD reduced (P<0·001) the pH of urine, and increased (P<0·05) Ca absorption. Plasma Ca concentration was not affected by DCAD, and DCAD did not affect the output of urinary hydroxyproline, a marker of bone resorption. Twice-daily supplementation of anionic salts was sufficient to reduce the pH of blood and increase gastrointestinal Ca absorption. There was no diurnal variation in the pH of urine, suggesting that time of sampling to determine efficacy of DCAD in reducing systemic pH was not important.

Rescue treatment and prevention of asthma using magnesium throat lozenges: Hypothesis for a mouth-lung biologically closed electric circuit

In the rescue treatment of acute asthma, injected and inhalant magnesium are relatively weak having demonstrated value only in severe illness, although theoretical and laboratory considerations suggest that magnesium should be strongly effective as an asthma rescue agent. It was hypothesized that a mouth-lung biologically closed electric circuit (BCEC) exists capable of nearly instantly transporting positively charged magnesium ions from the mouth and throat into the lungs. One hundred milligram magnesium (magnesium chloride) 4-g throat lozenges producing 100+ mM magnesium ion concentration in saliva were tested to determine if they had beneficial effects in asthma rescue and prevention. Subjects were selected based solely on need for asthma rescue, and lozenges were used as needed. Case histories are presented showing the nearly immediate effect of magnesium chloride throat lozenges in terminating and preventing asthma attacks. Throat lozenges containing magnesium chloride produced much more rapid and stronger benefits than has been reported for inhaled and injected magnesium. An added benefit from magnesium chloride lozenge treatment of asthma was relaxation. In this first report of its kind, magnesium chloride throat lozenges appeared to provide rescue benefits in the treatment of asthma equivalent to pharmaceutical asthma drugs. Countering these benefits, strong ionic magnesium solutions greatly increase rhinovirus, herpesvirus and Candida albicans in vitro, and appear to worsen these infections in humans. Magnesium lozenges releasing concentrated magnesium ions appear contraindicated during common colds, oral herpes infections, chronic rhinosinusitis, oral and respiratory infections in general, and their use must immediately be terminated if respiratory or oral symptoms worsen. Double-blind, placebo-controlled, clinical trials in people without respiratory or oral infections are needed to determine magnesium lozenge safety, and the extent by which drug treatment of asthma can be reduced.

Transport numbers in transdermal iontophoresis

Parameters determining ionic transport numbers in transdermal iontophoresis have been characterized. The transport number of an ion (its ability to carry charge) is key to its iontophoretic delivery or extraction across the skin. Using small inorganic ions, the roles of molar fraction and mobility of the co- and counterions present have been demonstrated. A direct, constant current was applied across mammalian skin in vitro. Cations were anodally delivered from either simple M(+)Cl(-) solutions (single-ion case, M(+) = sodium, lithium, ammonium, potassium), or binary and quaternary mixtures thereof. Transport numbers were deduced from ion fluxes. In the single-ion case, maximum cationic fluxes directly related to the corresponding ionic aqueous mobilities were found. Addition of co-ions decreased the transport numbers of all cations relative to the single-ion case, the degree of effect depending upon the molar fraction and mobility of the species involved. With chloride as the principal counterion competing to carry current across the skin (the in vivo situation), a maximum limit on the single or collective cation transport number was 0.6-0.8. Overall, these results demonstrate how current flowing across the skin during transdermal iontophoresis is distributed between competing ions, and establish simple rules with which to optimize transdermal iontophoretic transport.

[The protective effect of oral magnesium supplement on noise-induced hearing loss]

OBJECTIVES

We investigated the beneficial effect of magnesium in the prevention of noise-induced cochlear damage in guinea pigs by transient evoked otoacoustic emissions (TEOAE).

STUDY DESIGN

Thirty-nine guinea pigs with normal auropalpebral reflex were randomly divided into control (n=20) and study (n=19) groups. All the animals were subjected to wide-band noise standardized at a mean of 98+/-2 dB for 16 hours a day for 10 days in a sound isolated cabin. The study animals received 39 mmol/l MgCl2 throughout the study period starting from 15 days before noise exposure. Otomicroscopic examination, auditory brain stem response (ABR) and TEOAE measurements were performed before and after noise exposure. Tympanometric measurements were performed to eliminate possible middle ear pathologies.

RESULTS

Although the mean TEOAE response and reproducibility values showed significant decreases after noise application in the control group (p<0.001), they were not affected significantly in magnesium-treated animals. Post-exposure mean TEOAE response and reproducibility values significantly differed between the two groups (p<0.001). Noise-induced elevations in ABR thresholds were significant in both groups (p<0.001); however, it was noted that hearing levels were better preserved in the study group.

CONCLUSION

Our data suggest that oral magnesium intake may be beneficial in the prevention of cochlear damage in noise-induced hearing loss.

Magnesium Supplementation Combined with N-Acetylcysteine Protects against Postischemic Acute Renal Failure

Magnesium is a potent vasodilator whose effects have not been evaluated in renal ischemia. The antioxidant properties of N-acetylcysteine (NAC) partially protect animals from ischemic/reperfusion injury. This study was designed to evaluate magnesium supplementation, alone or combined with NAC, on ischemic acute renal failure. Rats were maintained on normal diets, supplemented or not with MgCl(2).6H(2)O (1% in drinking water) for 23 d, and some rats received NAC (440 mg/kg body wt) on days 20 to 23. On day 21, ischemia was induced by clamping both renal arteries for 30 min. Five groups were studied: Normal, ischemia, ischemia+magnesium, ischemia+NAC, and ischemia+magnesium+NAC. GFR (inulin clearance), renal blood flow (RBF), FEH(2)O, and FENa were determined. Serum magnesium was decreased in ischemia-only rats. Magnesium prevented postischemia GFR and RBF decreases but did not protect against tubular damage. However, NAC completely restored the tubular damage induced by ischemia/reperfusion. Semiquantitative immunoblotting showed that NAC prevented the decreased expression of Na-K-2Cl co-transporter and aquaporin 2 after renal ischemia/reperfusion. Untreated rats with acute renal failure demonstrated markedly decreased endothelial nitric oxide synthase expression. Significantly, treatment with NAC, magnesium, or both completely inhibited downregulation of endothelial nitric oxide synthase. The tubular necrosis scores were lower in rats that were treated with NAC alone or with the magnesium-NAC combination. Magnesium prevented postischemia GFR and RBF decreases but did not protect against tubular damage. The NAC protected tubules from ischemia, decreased infiltrating macrophages/lymphocytes, and had a mild protective effect on GFR. In ischemic/reperfusion injury, renal function benefits more from the magnesium-NAC combination than from magnesium alone.

Manganese enhanced magnetic resonance imaging of normal and ischemic canine heart

The ability of MnCl2 to enhance canine myocardium and to delineate ischemic areas is demonstrated. A dose-response curve was measured using T1 weighted images in 11 dogs. MnCl2 (36, 113, 360, and 3600 micromol) was infused over a period of 3 min. Signal intensity increased linearly with MnCl2 dose. At 113 micromol ( approximately 10 micromol/kg) the steady-state increase in intensity averaged 212 +/- 34%. No significant physiologic effects due to the infused MnCl2 were detected except at the highest dose where there was a cardiac depressive effect. Ischemia was induced by occluding the left anterior descending coronary artery in 5 dogs. At an infused dose of 113 micromol, MnCl2 clearly demarcated the ischemic zone during coronary occlusion. Contrast enhancement in the ischemic zone was less than 30% compared with normal tissue (P < 0.03). In conclusion, the intracellular contrast agent MnCl2 enhances the canine heart and shows promise in detecting ischemia at doses that do not cause adverse cardiac effects.