High-throughput drug screen identifies calcium and calmodulin inhibitors that reduce JCPyV infection

JC polyomavirus (JCPyV) is a nonenveloped, double-stranded DNA virus that infects the majority of the population. Immunocompetent individuals harbor infection in their kidneys, while severe immunosuppression can result in JCPyV spread to the brain, causing the neurodegenerative disease progressive multifocal leukoencephalopathy (PML). Due to a lack of approved therapies to treat JCPyV and PML, the disease results in rapid deterioration, and is often fatal. In order to identify potential antiviral treatments for JCPyV, a high-throughput, large-scale drug screen was performed using the National Institutes of Health Clinical Collection (NCC). Drugs from the NCC were tested for inhibitory effects on JCPyV infection, and drugs from various classes that reduced JCPyV infection were identified, including receptor agonists and antagonists, calcium signaling modulators, and enzyme inhibitors. Given the role of calcium signaling in viral infection including Merkel cell polyomavirus and simian virus 40 polyomavirus (SV40), calcium signaling inhibitors were further explored for the capacity to impact JCPyV infection. Calcium and calmodulin inhibitors trifluoperazine (TFP), W-7, tetrandrine, and nifedipine reduced JCPyV infection, and TFP specifically reduced viral internalization. Additionally, TFP and W-7 reduced infection by BK polyomavirus, SV40, and SARS-CoV-2. These results highlight specific inhibitors, some FDA-approved, for the possible treatment and prevention of JCPyV and several other viruses, and further illuminate the calcium and calmodulin pathway as a potential target for antiviral drug development.

The MEDLINE update on closed-circuit television

An alternative format for presentation of the MEDLINE Update is presented. Utilization of a statewide closed-circuit television network is time-saving and cost-effective for the audience. Differences in and audience response to this alternative programming are described.

The partial molar volumes of anesthetics in lipid bilayers

The excess volumes of mixing of benzyl alcohol, halothane, and methoxyflurane in water and in suspensions of several lipid bilayers have been determined at 25 degrees C using a novel excess volume dilatometer. The excess volumes of mixing in water were all found to be negative, whereas in lipid suspensions they were all more positive than those in water alone. From known partition coefficients the partial molar volumes of these three solutes in the lipid bilayers were calculated. These values were all close to the molar volumes of the pure anesthetics, as was a value determined for halothane in olive oil. Halothane was studied in dipalmitoylphosphatidylcholine below its phase transition, and was found to exhibit a much larger excess volume than in any other system we studied. The potency of these three anesthetics was determined in tadpoles. It was calculated that at equi-anesthetic doses these three agents caused an expansion in egg lecithin/cholesterol (2:1) bilayers of 0.21 +/- 0.015%. This result is consistent with the hypothesis that general anesthetics act by expanding membranes.

Quantitative hemodynamic effects of heart rate in aortic regurgitation

The hemodynamic effect of varying heart rate was studied in eight patients with aortic regurgitation. At the subjects' resting sinus rhythm and at a higher heart rate induced with right atrial pacing, left ventricular and aortic pressures and Fick cardiac outputs (FCO) were measured, and left ventricular biplane angiocardiograms were performed. Left ventricular volumes and left ventricular minute flow (LVMF) were determined from the angiograms. Regurgitant flow was quantitated by subtracting the FCO from LVMF. Increased heart rate produced highly significant reductions in the left ventricular end-diastolic pressure (LVEDP), left ventricular end-diastolic volume, and stroke volume. End-diastolic circumferential stress (EDCS) and end-diastolic load (EDL) were abnormally high at resting sinus rhythm and were markedly decreased with increased heart rate. FCO increased, but no significant changes were observed in either the LVMF or the regurgitant flow per minute.

Bradycardia in aortic regurgitation may cause pulmonary congestion secondary to high LVEDP and may accelerate left ventricular dilatation secondary to markedly elevated EDCS and EDL. The possible benefits of preventing bradycardia in aortic regurgitation by chronic demand pacing is currently being tested.