Preliminary clinical experience with the antiarrhythmic effect of PGF2a

A total dosage up to 1 mg PGF_2a as i.v. infusions of 10–40 μg/min. was investigated on patients with arrhythmias of several kinds. We found therapeutic effects in 5 of 6 patients with constant extrasystoles and in one patient with digitalis - induced partial AV-block respectively. In 3 of 4 patients with acute tachyarrhythmias the results were not convincing, probably due to a dosage not high enough. An increase of the diastolic stimulation threshold usually seen with other antiarrhythmics was not to be observed in 3 patients. The mechanism of action of PGF_2a has not yet been clarified.     

The dynamical structure of the RNA in alfalfa mosaic virus studied by 31P-nuclear magnetic resonance

The structure of the viral RNA in alfalfa mosaic virus (AlMV) was investigated by means of 31P-nuclear magnetic resonance (NMR). It was found that the 31P-NMR line width of AlMV Top a particles is significantly smaller than that of the larger Bottom particles. At low temperatures, the totational correlation time of the 31P nuclei essentially equals the tumbling rate of the virus particle, indicating that the RNA is contained rigidly inside the virion. At more elevated temperatures, the NMR line width sharpens more than expected on the basis of viscosity changes and the RNA exhibits internal mobility. The occurrence of internal mobility is paralleled by an increased internal mobility of the N-terminal part of the coat protein, as could be observed by 1H-NMR spectroscopy. The influence of EDTA on the 31P-NMR line width appeared to be negligible, which is in agreement with the idea that AlMV does not 'swell' like several other RNA-containing plant viruses.     

Synchrony of Long Duration in Suspension Cultures of Mammalian Cells

THE high-sulphur proteins of α-keratins, which constitute the non-filamentous matrix between the microfibrils, comprise several major groups of proteins, each group consisting of a number of closely related components. They are obtained in a soluble form by reduction of the disulphide bonds of wool and preferential extraction with alkaline thioglycollate at high ionic strength¹. The thiol groups are subsequently stabilized by alkylation with iodoacetic acid.