BACKGROUND: Magnesium, ropivacaine, gentamicin, and rocuronium block neuromuscular (NM) transmission by different mechanisms. Therefore, concurrent administration of these agents may induce prolonged muscle paralysis via synergistic interaction. This study investigated the efficacy and safety of NM block caused by the administration of high concentrations of magnesium in combination with ropivacaine, gentamicin, and rocuronium. METHODS: Eighty-three left phrenic nerve-hemidiaphragms from male SD rats (150-250 g) were hung in Krebs solution. Three consecutive single twitch tension (ST, 0.1 Hz) and one tetanic tension (TT, 50 Hz for 1.9 s) were obtained before drug application and at each new drug concentration. The concentration of MgCl2 and MgSO4 in Krebs solution was increased until an 80 to 90% reduction in ST was reached. To test the effects of combinations of NM agents, a Krebs solution was premixed with MgCl2 alone, MgCl2 and ropivacaine, or MgCl2, ropivacaine, and gentamicin. The concentration of ropivacaine, gentamicin, or rocuronium was then progressively increased until an 80 to 90% reduction in ST was reached. The effective concentrations were estimated with a probit model. RESULTS: The potency of MgCl2 was greater than that of MgSO4, and pretreatment with MgCl2 increased the potency of gentamicin and rocuronium. Unexpectedly, MgCl2 did not potentiate ropivacaine, and the potency of gentamicin and rocuronium failed to show an increase when premixed with 0.5 microM ropivacaine. CONCLUSIONS: The concomitant administration of high concentrations of magnesium and ropivacaine together with clinically relevant concentrations of gentamicin or rocuronium potentiated NM blockade but not with clinically relevant concentrations of ropivacaine.
Animals ; Gentamicins* ; Humans ; Magnesium Chloride ; Magnesium* ; Male ; Neuromuscular Blockade* ; Paralysis ; Rats

The present study is an attempt to delineate the effect of various salt administrations on the changes of blood pH and electrolytes, especially the nature of serum calcium, total and ionic, and serum magnesium. Thirty five male rabbits weighing 1.9 to 2. 5kg were used in this experiment. At the end of the three days diet adjustment period, the animals were divided into seven groups; Group I; Control, Group II; Ammonium chloride oral administration, Group III; Oral administration of sodium bicarbonate, Group IV; Potassium chloride intraveneous injection, Group V; Sodium chloride intravenous injection, Group VI; Calcium chloride intravenous injection, and Group VII; Magnesium chloride intravenous injection. The blood pH was determined by the method by Astrup and bicarbonate in serum by the method of Van Slyke and Neill. Sodium and potassium in serum were determined with an EEL flame photometer. Chloride was determined by the method of Schales and Schales and inorganic phosphorous by the method of Fiske and Subbarrow. Serum total calcium and magnesium were determined according to the method of chelometric titration with Eriochrome blue S.E. Serum ionic calcium was determined by the method of Yanagisawa. The results of this study are as follows: 1. The oral administration of ammonium chloride produced a significant decrease in blood pH. The serum concentrations of bicarbonate, magnesium and potassium were steadily decreased, but serum chloride, serum total and ionic calcium concentrations were increased through the experiment. 2. Sodium bicarbonate ingestion increased the concentration of bicarbonate, magnesium and serum ionic calcium markedly and serum ionic calcium slightly. The blood pH was significantly increased but serum chloride concentration was markedly reduced after ingestion of sodium bicarbonate However, serum potassium and inorganic phosphorus concentrations were decreased slightly. 3. The blood pH was dropped in the first two hours of intravenous injection of potassium chloride and tended to rise again significantly. the concentration of sodium and chloride in serum was increased markedly in two hours of injection but reduced after six hours to control level. Serum phosphorus, total and ionic calcium were reduced steadily, but serum concentration of magnesium, potassium and bicarbonate concentrations were slightly increased through the experiment 4. After sodium chloride was given, intravenously, there was a sustained increase in the concentration of serum sodium, potassium, phosphorus and bicarbonate but the blood pH was decreased in the first two hours and significantly elevated through the experiment. The serum concentration of chloride, magnesium, total and ionic calcium was decreased slightly. 5. B100d pH was slightly increased and the concentration of chloride was elevated sharply after injection of calcium chloride intravenously in the first two hours and come to control level in twenty-four hours. Serum sodium concentration was elevated steadily through the experiment. The concentration of total and ionic calcium in serum was elevated after injection but come to control level in twenty four hours of injection. Serum potassium and magnesium concentrations were decreased slightly in the first two hours and increased in four hours of injection. 6. Magnesium chloride intravenous injection produced a decrease in blood pH and serum concentration of bicarbonate in the first few hours and increase after 6 hours of injection. Serum magnesium, and inorganic phosphorus levels were increased after injection but the concentration of inorganic phosphrous was decreased markedly in twenty four hours of injection. Serum concentration of chloride, ionic calcium and potassium wag markedly reduced.
Administration, Oral ; Ammonium Chloride ; Animals ; Calcium ; Calcium Chloride ; Diet ; Eating ; Eels ; Electrolytes* ; Humans ; Hydrogen-Ion Concentration* ; Injections, Intravenous ; Magnesium ; Magnesium Chloride ; Male ; Phosphorus ; Potassium ; Potassium Chloride ; Rabbits ; Sodium ; Sodium Bicarbonate ; Sodium Chloride

Bovine pericardial bioprosthesis treated with glutaraldehyde is one of the most popular prosthetic materials, but late calcific degeneration must be solved. According to the alleged hypothesis of this calcification mechanism the free aldehyde groups on the surface of the tissue treated with glutaraldehyde bind to the circulating free calcium and induce mineralization. For mitigating the calcific degeneration, I added MgCl2 into the 0.625% glutaraldehyde solution to compete with calcium for binding to free aldehyde from the glutaraldehyde. I prepared 60 pieces of square shaped bovine pericardia and fixed in the 0.625% glutaraldehyde solution as control group (group 1), and the other 60 pieces in the same glutaraldehyde solution with 4g/L MgCl2 6H2O as the other group (group 2). After fixation for 1 month these were implanted into the bellies of 60 Sprague-Dawley rats subdermally and extracted on 1 month, 2 months, 3 months and 6 months later. With atomic absorption spectophotometry I measured the deposited calcium amount with the following results; 1 month and 2 months after implantation I could not find any differences between two groups, but in the 3rd month calcium was 1.738 mg/g in group 1 and 0.786 mg/g in group 2 and in the 6th month calcium had risen to 3.102 mg/g in group 1 and 1.623 mg/g in group 2, which has statistical significance (p<0.05). This means magnesium shows meaningful calcium mitigation effects on subcutaneously implanted bovine pericardium in the rat models.
Absorption ; Animals ; Bioprosthesis ; Calcinosis ; Calcium* ; Glutaral ; Heterografts ; Magnesium ; Magnesium Chloride ; Models, Animal ; Pericardium ; Rats* ; Rats, Sprague-Dawley

BACKGROUND: There have been numerous studies to define the diurnal variation of urinary excretions of substances. It is known that this variation is influenced by many factors. This diurnal variation also affects results of quantitative analysis of random urine. The purpose of this study is to evaluate the maximum excretion time of day for representative urinary analytes and to elucidate the most appropriate time for spot urine quantitative analysis. METHODS: The concentrations of following urinary analytes were measured on healthy male and female volunteers at 06, 08, 12, 16 and 24 hours in August 1995, March 1996 and January 1997: protein, amylase, urea nitrogen, creatinine, uric acid, sodium, potassium, chloride, magnesium, calcium and inorganic phosphorus were measured by Hitachi Model 747 automatic analyzer and microalbumin by Beckman Array 360. The statistical analyses of results were performed by one-way ANOVA and multiple comparison for the significance of difference. RESULTS: The excretion of protein, amylase, urea nitrogen, creatinine, sodium, potassium, chloride, magnesium and inorganic phosphorus showed the diurnal variations. The peak excretion time of protein, amylase, urea nitrogen and creatinine was at early morning. However, that of sodium, pota-ssium, chloride, magnesium and inorganic phosphorus was at afternoon. The excretion of urea nitrogen, sodium, chloride and magnesium revealed the seasonal variations. The excretion of urea nitrogen, sodium and chloride was increased during winter. CONCLUSIONS: The morning urine specimen is considered to be the most appropriate for analysing protein and nitrogenous substances and the afternoon specimen is appropriate for electrolytes.
Amylases ; Calcium ; Creatinine ; Electrolytes* ; Female ; Humans ; Magnesium ; Magnesium Chloride ; Male ; Nitrogen ; Phosphorus ; Potassium ; Seasons ; Sodium ; Urea ; Uric Acid ; Volunteers

BACKGROUND: Several ions, such as calcium or magnesium ions, are reported to have regulatory effects on epidermal permeability barrier homeostasis. Recently, it has been suggested that strontium ion can play a substitutive role for calcium ion in various cellular reactions. OBJECTIVE: This study was conducted to investigate the effects of strontium ion, either alone or in combination with calcium or magnesium ions, on epidermal permeability barrier homeostasis. METHODS: Female hairless mice were used to study the effects of various ions on epidermal permeability barrier recovery. Calcium chloride solution, magnesium chloride solution or strontium chloride solution were topically applied to barrier-disrupted skin, either alone or simultaneously. Change of transepidermal water loss, which represents permeability barrier function, was measured by TEWameter and morphological change was also observed by light and electron microscopy. RESULTS: Topical application of strontium chloride solution accelerated permeability barrier recovery rate, compared with vehicle-applied skin. Magnesium chloride solution also accelerated barrier recovery rate, as reported in previous studies. Interestingly, simultaneous application of strontium and calcium ions significantly accelerated barrier recovery rate, compared to application of strontium or calcium ion alone. Nile red staining confirmed the increased neutral lipid deposition in strontium ion applied skin. Electron microscopic observation also revealed an increased lamellar body secretion in strontium ion applied skin. CONCLUSION: Strontium ion can play a regulatory role in epidermal permeability barrier homeostasis due to, at least in part, its competitive action on calcium ion for the same ion channel.
Animals ; Calcium ; Calcium Chloride ; Female ; Homeostasis ; Humans ; Ion Channels ; Ions* ; Magnesium ; Magnesium Chloride ; Mice ; Mice, Hairless ; Microscopy, Electron ; Permeability* ; Skin ; Strontium*

BACKGROUND: Based on previously reported articles, magnesium sulphate seemed to cause a motor paralysis, but not complete analgesia when administered intrathecally alone, but is likely to have a partial analgesic effect. Accordingly, we tested a hypothesis that magnesium sulphate might potentiate the analgesic effect when coadministered intrathecally with bupivacaine. METHODS: Eighteen male Sprague-Dawley rats were allocated into three groups of six animals each. The duration of sensory blockade was determined by observing the period when the animal did not vocalize and/or withdraw (struggle) while forceps-pinch tests were applied to a hindlimb paw. The six animals in each of the following three groups were injected intrathecally with 0.03 ml of the different test substances: (group 1) 16.7% magnesium sulphate {50% magnesium sulphate (0.01 ml) + 0.9% sodium chloride (0.02 ml)}; (group 2) 50% magnesium sulphate (0.01 ml) + 0.5% bupivacaine (0.02 ml); (group 3) 0.33% bupivacaine {0.5% bupivacaine (0.02 ml) + 0.9% sodium chloride (0.01 ml)}. RESULTS: Sensory blockade in the hindlimbs was observed only in group 2 and lasted for 12 to 14 minutes, while there were no sensory blockades in group 1 and group 3. CONCLUSIONS: Magnesium sulphate potentiated the analgesic effect of bupivacaine when coadministered intrathecally with bupivacaine in rats. These results suggest that intrathecal administration of magnesium sulphate may be a useful adjunct to spinal bupivacaine anesthesia.
Analgesia ; Anesthesia ; Animals ; Bupivacaine* ; Hindlimb ; Humans ; Magnesium* ; Male ; Paralysis ; Rats* ; Rats, Sprague-Dawley ; Sodium Chloride

We have experienced two patients who had hypokalemic metabolic alkalosis as well as hypomagnesemia and hypocalciuria with elevated plasma renin activity. We have performed renal clearance study after water loading, administration of furosemide and thiazide in two patients and two normal controls. Maximal free water clearance per 100 mL glomerular filtration rate(CH2O) and distal fractional chloride reabsorption[CH2O/(CH2O+CCl)] in our patients were reduced than the controls. Chloride clearance(CCl) was increased after furosemide administration but not after thiazide administration. Distal fractional chloride reabsorption[CH2O/(CH2O+CCl)] was dramatically decreased by furosemide administration in our patients, whereas thiazide had little effect on it. Fractional excretion of sodium, chloride, magnesium, calcium was increased by furosemide administration, whereas thiazide administration had little effect on this parameters. These findings suggested the presence of a defect in the distal convoluted tubule rather than in the thick ascending loop of Henle. Herein, we report two cases of Gitelman's syndrome diagnosed by renal clearace study after water loading, administration of furosemide and thiazide.
Alkalosis ; Calcium ; Filtration ; Furosemide ; Gitelman Syndrome* ; Humans ; Loop of Henle ; Magnesium Chloride ; Plasma ; Renin ; Sodium ; Water

The isolated rabbit kidney was perfused with 4 kinds of perfusates which had different ionic compositions, in order to investigate the effects of divalent cations, Mg and Ca, on the renal autoregulation. Four kinds of perfusates are full-balanced perfusate (FBP), perfusate subtracted both CaCl2and MgCI2 from FBP, perfusate subtracted only CaCI, from FBP, and perfusate subtracted only MgCl2 from FBP. The composition of FBP is 6% hydroxyethyl starch in 0.9% NaCl (McGaw Lab. USA) containing Na-acetate 5.0, K2HPO4 5.0, CaCls 1.2, MgCl2 0.5, and glucose 5.O mM/L. Renal Perfusate Flow (RPF) as related to various renal arterial perfusion pressure (RAP) was directly measured with flow-meter attached to the perfusion system. Total renal resistance (Rr) was calculated from RAP & RPF (RT=RAP/RPF). Alterations in renal autoregulation, when different perfusates were perfused, were estimated by pressure-flow curve in every run of perfusion experiments. The results obtained were as follows: 1) Kidney perfused with FBP revealed autoregulation within the range of 100~180 mmHg RAP. Renal Perfusate Flow in the autoregulation zone was 5.0 ml,min/gm. 2) The autoregulation was not appeared in the experiments perfused with the solution subtracted both CaCl2 and MgCI2 from FBP. 3) Kidney perfused with FBP-CaCI2 revealed the autoregulation, which had the autoregulation zone of 110~180 mmHg RAP, and 5. 5 m1/min/gm RPF. However, it was not present in the kidney perfused with FBP-MgCl2. 4) The time course of autoregulation was observed on the pressure-flow curve; autoregulation was continued approximately for 15 minutes, and then deteriorated rapidly. 5) Total renal resistance calculated was proportionately increased as the RAP increased within the regulation zone. Below and above the zone, it was almost inversely related to the RAP. From the above results, it was concluded that Mg is the essential factor in the renal autoregulation and suggested that Mg could have a key role on the neuromuscular transmission, excitability of muscular cell membrane, or the process of intracellular contraction.
Cations, Divalent ; Cell Membrane ; Glucose ; Homeostasis* ; Ions* ; Kidney* ; Magnesium Chloride ; Perfusion ; Starch

To evaluate the nephrotoxicity of cisplatin, serum levels of sodium, potassium, chloride, calcium, phosphorous, magnesium, BUN, creatinine and creatinine clearance were measured before and after administration of cisplatin in 18 cases of patients with malignant neoplasm. The results were as follows: 1) Serum calcium, magnesium, potassium and BUN levels were changed after cisplatin administration, but those changes were not statistically significant. 2) The mean value of creatinine clearance was not decreased significantly after treatment with cisplatin. 3) Acute renal failure was developed in one case, and four cases of hypocalcemia, hypomagnesemia were also detected after administration of cisplatin.
Acute Kidney Injury ; Calcium ; Calcium Chloride ; Cisplatin* ; Creatinine ; Humans ; Hypocalcemia ; Magnesium ; Potassium ; Sodium

Entomopathogenic fungi are promising pest-control agents but their industrial applicability is limited by their thermosusceptibility. With an aim to increase the thermotolerance of Isaria fumosorosea SFP-198, moisture absorbents were added to dried conidial powder, and the relationship between its water potential and thermotolerance was investigated. Mycotized rice grains were dried at 10degrees C, 20degrees C, 30degrees C, and 40degrees C and the drying effect of each temperature for 24, 48, 96, and 140 hr was determined. Drying for 48 hr at 10degrees C and 20degrees C reduced the moisture content to < 5% without any significant loss of conidial thermotolerance, but drying at 30degrees C and 40degrees C reduced both moisture content and conidial thermotolerance. To maintain thermotolerance during storage, moisture absorbents, such as calcium chloride, silica gel, magnesium sulfate, white carbon, and sodium sulfate were individually added to previously dried-conidial powder at 10% (w/w). These mixtures was then stored at room temperature for 30 days and subjected to 50degrees C for 2 hr. The white carbon mixture had the highest conidial thermotolerance, followed by silica gel, magnesium sulfate, and then the other absorbents. A significant correlation between the water potential and conidial thermotolerance was observed in all conidia-absorbent mixtures tested in this study (r = -0.945). Conidial thermotolerance in wet conditions was evaluated by adding moisturized white carbon (0~20% H2O) to conidia to mimic wet conditions. Notably, the conidia still maintained their thermotolerance under these conditions. Thus, it is evident that conidial thermotolerance can be maintained by drying mycotized rice grains at low temperatures and adding a moisture absorbent, such as white carbon.
Calcium Chloride ; Carbon ; Edible Grain ; Fungi ; Magnesium Sulfate ; Silica Gel ; Sodium ; Spores, Fungal ; Water