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Biomedical subjects

M Wiener

Publications and source records attributed to M Wiener.

96 records · Page 6Linked to original sources
PubMedDate not supplied

Oral magnesium intake reduces permanent hearing loss induced by noise exposure.

INTRODUCTION: Following animal experiments where correlations were observed between serum magnesium level and noise-induced permanent hearing threshold shifts (NIPTS), we tested the prophylactic effect of magnesium in human subjects exposed to hazardous noise. METHODS: Subjects were 300 young, healthy, and normal-hearing recruits who underwent 2 months of basic military training. This training necessarily included repeated exposures to high levels of impulse noises while using ear plugs. During this placebo-controlled, double-blind study, each subject received daily an additional drink containing either 6.7 mmol (167 mg) magnesium aspartate or a similar quantity of placebo (Na-aspartate). RESULTS: NIPTS was significantly more frequent and more severe in the placebo group than in the magnesium group, especially in bilateral damages. NIPTS was negatively correlated to the magnesium content of blood red cells but especially to the magnesium mononuclear cells. Long-term additional intake of a small dose of oral magnesium was not accompanied by any notable side effect. CONCLUSION: This study may introduce a significant natural agent for the reduction of hearing damages in noise-exposed population.

Administration, Oral↗
PubMedDate not supplied

Creatine kinase activity decrease with short-term freezing.

Freezing of serum samples at -30 degrees C without protective agents is the simplest and least expensive method of storage in serum banks. We investigated the stability of creatine kinase (CK) in human sera after freezer storage under such conditions for 24 h (n = 30) or for 2 or 4 weeks (n = 99). CK activity was measured in fresh sera and compared to matched thawed sera after freezer storage at the designated time intervals. The enzyme's median activity decreased significantly after 24 h, 2 weeks, and 4 weeks of freezer storage by 2.6, 5.9, and 8.3%, respectively (p < 0.0001, r = 0.99). Sex or high CK initial values had no significant effect on these results. We conclude that freezer storage of serum at -30 degrees C, even for short periods, causes a steady and significant decline in CK activity. These results should be taken into consideration when analyzing CK activity in frozen sera for research or clinical purposes.

Blood Banks↗
PubMedDate not supplied

Airborne field hospital in disaster area: lessons from Armenia (1988) and Rwanda (1994).

The outcome of survivors within disaster areas largely depends upon the quick reallocation and operation of logistic and medical support systems. Enthusiastic media equipped with advanced communication systems, reveal mass human suffering in real time. But, the response period required for the organization of rescue systems is much slower and is most frustrating. In this article, we present our experience in quick deployment and operation of airborne field hospitals gained following the earthquake disaster in Armenia in 1988 and the civil war in Rwanda in 1994. Deployment of improvised, volunteer-based, military field hospitals was feasible within 24 hours after the decision was made. A multi-disciplinary structure enabled an effective, flexible mode of operation and reduced the dependency on mericulous, time-consuming assessments of requirements prior to deployment. These missions are a paradigm for the successful incorporation and integration within the capabilities of military infrastructure of volunteer professionals drafted from civil medical facilities. Such field hospitals could provide backup for primary care medical systems in disaster areas and substitute or take some pressure off of local hospitals, particularly when evacuation systems are insufficient.

Aircraft↗
PubMedDate not supplied

Mirex kinetics in the rhesus monkey. I. Disposition and excretion.

Three female rhesus monkeys were given 14C-Mirex (5.23 mCi/mmol) iv (two animals) or po (one animal) in a dose of about 1 mg/kg for the purpose of determining the distribution and excretion of this polycyclic perchlorinated insecticide. Blood, plasma, urine, feces, and tissue samples were analyzed for 14C content. Monkeys were autopsied 23, 106, and 388 days after receiving 14C-Mirex. Following iv administration, plasma 14C showed a rapid decrease over the first few hours from the initial high levels. In the monkey given the compound orally, 14C first appeared in the plasma at 2 hr and reached a maximum at 5 hr. Thereafter, the decline in plasma radioactivity paralleled that found in the animals dosed i.v. After 2 weeks, the rate of decline in all animals was very slow. Excretion and tissue distribution of Mirex were essentially the same whether the compound was given po or iv. Less than 0.6% of the dose was found in the urine. 14C was excreted in the feces for the duration of the experiment with a maximum cumulative excretion of 7% after 388 days. At autopsy all tissues analyzed contained 14C. The highest concentration of 14C was found in the fat (estimated to contain at least 80% of the dose), followed by adrenal, peripheral nerve, thyroid, and skin. Chemical analysis of the nature of the radioactivity in fat and feces showed that at least 95% and was present as unchanged Mirex. There was a small amount of a compound more polar than Mirex in the feces, containing less than 3% of the fecal radioactivity.

Animals↗
PubMedDate not supplied

Mirex kinetics in the rhesus monkey. II. Pharmacokinetic model.

14C-Mirex was given iv and po to female rhesus monkeys (Macaca mulatta) and radioactivity was measured in plasma, urine, and feces at intervals after dosing and in tissues when animals were killed. Graphical analysis of plots of the logarithm of plasma concentration vs. time was used to provide estimates of the values of the first-order rate constants required by the proposed pharmacokinetic models. A BASIC-language program, FITKIN, was used to obtain numerical solutions to the differential equations for each model and to adjust the estimates to obtain a normalized, least squares fit. Of several models postulated, a mammillary, four-compartment, open-system model, providing for the urinary excretion of Mirex from a "central" compartment and for the fecal excretion of Mirex from a "fast" tissue compartment, yielded theoretical data in agreement with observed values. This model predicted that the accumulation of Mirex into fat would be retarded by the presence of a "slow" tissue compartment so that distribution equilibrium would take about half a year. From that time to the end of a 5-year projection, little decline in the quantities of Mirex was predicted for any compartment. Sequestration in fat and a lack of metabolism were responsible for the long biological half-life of Mirex in the rhesus monkey.

Adipose Tissue↗