Dynamics of ethanol-induced transmitter packet release in the frog neuromuscular junction

Intervals of spontaneous miniature endplate potentials (MEPPs) are usually thought to follow random kinetics because number vs. interval size plots can fit a Poisson distribution such that the largest number of intervals are found in the smallest interval bin. Even though several studies report that MEPPs have a tendency to clump together, an alternative dynamic has not gained acceptance. We found that spontaneous MEPP interval plots with commonly used bin sizes (10 ms or larger) from muscle fibers of diameters usually studied (20 microns) also skew to the smallest interval bin. In order to study very small junctions which do not generate enough intervals for a detailed analysis of high resolving power (small bin width) at normal frequencies of 0.05 MEPPs/s we increased MEPP frequencies with ethanol to obtain large samples. Ethanol accentuated the normal clustering of MEPPs and number vs. interval plots of 0.5 ms show periodic peaks at 400 Hz. A periodogram of power vs. frequency also showed a preferred frequency of 400 Hz. The first peak indicates a refractory period and the 400 Hz oscillation demonstrates that MEPPs are not independent. A release channel with a rhythmical nature is discussed as a possible molecular process which generates clusters of MEPPs.     

Prevalence and associated factors of intestinal parasite infection by HIV infection status among asymptomatic adults in rural Gabon

IntroductionIntestinal parasites infections are endemic in Gabon. Nevertheless, they are rarely described in people living with HIV (PLHIV).ObjectiveThe frequency of intestinal parasite infection was estimated and compared between HIV-positive and HIV uninfected individuals in Gabon; factors associated with intestinal parasites were also analysed.Material and MethodsUsing a cross-sectional study design sociodemographic data, life style habits, antiretroviral therapy, cotrimoxazole use and CD4 cell count were recorded.. Stool samples from participants living in Koulamoutou and Oyem were analysed using microscopy. Chi-squared or fisher''s exact tests and logistic regression were performed.ResultsAmong participants (n=332), female gender was predominant (73.7%; n=135/183) and the median age was 45 [33–57] years old. Among 183 samples, 53.6% (n = 98/183) were infected by intestinal parasites. The proportion was higher (72.1%) in HIV negative participants compared to PLHIV (42.6%) (p <0.01). PLHIV were more frequently poly-infected. Infection was frequent in patients using external toilets and tap water (>70.0%).ConclusionPrevalence of intestinal parasites is higher in seronegative participants but polyparasitism is more frequent in PLHIV. Strategies are focused on HIV negative population, but this study shows the importance of sensitization for PLHIV to improve their quality of life.