Trimethyloxonium modification of single batrachotoxin-activated sodium channels in planar bilayers. Changes in unit conductance and in block by saxitoxin and calcium

Single batrachotoxin-activated sodium channels from rat brain were modified by trimethyloxonium (TMO) after incorporation in planar lipid bilayers. TMO modification eliminated saxitoxin (STX) sensitivity, reduced the single channel conductance by 37%, and reduced calcium block of inward sodium currents. These effects always occurred concomitantly, in an all-or-none fashion. Calcium and STX protected sodium channels from TMO modification with potencies similar to their affinities for block. Calcium inhibited STX binding to rat brain membrane vesicles and relieved toxin block of channels in bilayers, apparently by competing with STX for the toxin binding site. These results suggest that toxins, permeant cations, and blocking cations can interact with a common site on the sodium channel near the extracellular surface. It is likely that permeant cations transiently bind to this superficial site, as the first of several steps in passing inward through the channel.     

Phosphorylation of chromosomal proteins as a function of age and its modulation by calcium

$\text{In vitro}$ phosphorylation of histones and non histone chromosomal proteins (NHCP) and its modulation by calcium have been studied using slices of cerebral hemisphere of rats of various ages. Phosphorylation of histones decreases, and that of NHCP increases with increasing age. Calcium inhibits phosphorylation of histones of young and adult rats, but stimulates phosphorylation of NHCP. Phosphorylation of H1 and H4 histones is greater than that of other histones, and calcium inhibits their phosphorylation more markedly than of other histones. The significance of such modifications of chromosomal proteins in the aging process is discussed.     

Acceleration Workspace of Cooperating Multi-Finger Robot Systems

We present a mathematical method for acceleration workspace analysis of cooperating multi-finger robot systems using a model of point-contact with friction. A new unified formulation from dynamic equations of cooperating multi-finger robots is derived considering the force and acceleration relationships between the fingers and the object to be handled. From the dynamic equation, maximum translational and rotational acceleration bounds of an object are calculated under given constraints of contact conditions, configurations of fingers, and bounds on the torques of joint actuators for each finger. Here, the rotational acceleration bounds can be applied as an important manipulability index when the multi-finger robot grasps an object. To verify the proposed method, we used a set of case studies with a simple multi-finger mechanism system. The achievable acceleration boundary in task space can be obtained successfully with the proposed method and the acceleration boundary depends on the configurations of fingers.     

Potential for Controlling Cholera Using a Ring Vaccination Strategy: Re-analysis of Data from a Cluster-Randomized Clinical Trial

IntroductionVaccinating a buffer of individuals around a case (ring vaccination) has the potential to target those who are at highest risk of infection, reducing the number of doses needed to control a disease. We explored the potential vaccine effectiveness (VE) of oral cholera vaccines (OCVs) for such a strategy.ConclusionsThese findings suggest that high-level protection can be achieved if individuals living close to cholera cases are living in a high coverage ring. Since this was an observational study including participants who had received two doses of vaccine (or placebo) in the clinical trial, further studies are needed to determine whether a ring vaccination strategy, in which vaccine is given quickly to those living close to a case, is feasible and effective.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00289224","term_id":"NCT00289224"}}NCT00289224     

Expression of muscle creatine kinase gene of mice and interaction of nuclear proteins with MEF-2, E boxes and A/T-rich elements during aging

The changes in the expression of muscle creatine kinase (MCK) gene in the heart and skeletal muscle of mice during aging were studied. Its expression declines as a function of age in the heart, however, no age-related change is observed in the skeletal muscle. The cis-acting elements, MEF-2, E boxes and A/T rich elements present in the enhancer region of the mouse MCK gene are known to regulate the expression of the gene. Hence, these elements were subcloned and electrophoretic mobility shift assay was carried out to investigate the changes in the binding of the nuclear trans-acting protein factors of the heart with these elements as a function of age. These factors showed specificity for the respective cis-acting elements. Furthermore, the binding of these factors was found to decrease during aging which may contribute to the age-related decline in the expression of the MCK gene and activity of the heart.