53 research outputs found
Magnesium induces neuronal apoptosis by suppressing excitability
In clinical obstetrics, magnesium sulfate (MgSO4) use is widespread, but effects on brain development are unknown. Many agents that depress neuronal excitability increase developmental neuroapoptosis. In this study, we used dissociated cultures of rodent hippocampus to examine the effects of Mg++ on excitability and survival. Mg++-induced caspase-3-associated cell loss at clinically relevant concentrations. Whole-cell patch-clamp techniques measured Mg++ effects on action potential threshold, action potential peak amplitude, spike number and changes in resting membrane potential. Mg++ depolarized action potential threshold, presumably from surface charge screening effects on voltage-gated sodium channels. Mg++ also decreased the number of action potentials in response to fixed current injection without affecting action potential peak amplitude. Surprisingly, Mg++ also depolarized neuronal resting potential in a concentration-dependent manner with a +5.2âmV shift at 10âmM. Voltage ramps suggested that Mg++ blocked a potassium conductance contributing to the resting potential. In spite of this depolarizing effect of Mg++, the net inhibitory effect of Mg++ nearly completely silenced neuronal network activity measured with multielectrode array recordings. We conclude that although Mg++ has complex effects on cellular excitability, the overall inhibitory influence of Mg++ decreases neuronal survival. Taken together with recent in vivo evidence, our results suggest that caution may be warranted in the use of Mg++ in clinical obstetrics and neonatology
Analysis of apoptosis methods recently used in Cancer Research and Cell Death & Disease publications
Aeromedical Evacuation, the Expeditionary Medicine Learning Curve, and the Peacetime Effect.
INTRODUCTION: Organizational proficiency increases with experience, which is known as a learning curve. A theoretical peacetime effect occurs when knowledge and skills degrade during peacetime. In this study, the intertheater evacuation system was examined for evidence of a military learning curve and peacetime effect.
MATERIALS AND METHODS: Data on medical evacuations from U.S. Central Command occurring between January 1, 2003, and December 31, 2022, were acquired from the TRANSCOM Regulating and Command & Control Evacuation System. Priority mission evacuation time corresponding to peak periods of activity in Iraq and Afghanistan and minimal activity in Afghanistan was analyzed. Any reduction or increase in the delivery time of casualties would be considered a change in proficiency.
RESULTS: There was a marginal monthly decline of 0.019âdays (27.4âmin) to perform a priority evacuation from Iraq (95% confidence interval [CI], 0.009 to 0.028âdays, Pâ\u3câ.001) and a decline of 0.010âdays (14.4âmin) from Afghanistan (95% CI, 0.003 to 0.016âdays, Pâ=â.004) over 40âmonths from peak monthly average times. There was a monthly marginal increase in priority evacuation average time from Afghanistan of 0.008âdays (11.5âmin) (95% CI, 0.005 to 0.011, Pâ\u3câ.001) between January 2013 and December 2020. The number of monthly evacuations estimated to maintain or improve monthly average evacuation time is approximately 50.
CONCLUSIONS: An intertheater aeromedical evacuation system increased in proficiency during periods of conflict and declined during relative peacetime. There is evidence of a peacetime effect on intertheater aeromedical evacuation
Portrait of Adele Rosenwald Levy
Portrait of Adele Rosenwald Levy, Chair of the Womens Division of United Jewish Appeal, in a library.Digital ImageDigital finding aid
- âŠ