Enhanced isolation of Mycoplasma pneumoniae from throat washings with a newly-modified culture medium.

Two hundred throat washings, previously screened and presumed negative for Mycoplasma pneumoniae in conventional mycoplasma culture media, were retested for the organism in a modified medium (PS-4) initially developed for cultivation of a tick-derived Mycoplasma (spiroplasma). The organism was rapidly identified with an agar plate immunofluorescence procedure. M. pneumoniae was isolated from 69 (34.5%) of the 200 "negative" specimens cultured on a diphasic SP-4 medium, in contrast to 10 isolations (5%) made on conventional diphasic mycoplasma medium. This enhanced recovery of M. pneumoniae represented a combination of a superior culture medium and a more efficient identification technique. The findings suggest that these procedures might be effectively applied to the recovery of M. pneumoniae from all likely host and that improved recovery of the organism may aid in the interpretation of a number of puzzling questions about the epidemiology of M. pneumoniae infections.     

Removal of common bile duct stones after emergency drainage of the gall bladder

Because of the hazards associated with cholecystectomy and choledochotomy in acute biliary tract disease, cholecystostomy may be performed as an emergency procedure. Postoperative tube cholangiography in such patients may show calculi in the biliary ducts. The percutaneous extraction of these calculi prior to cholecystectomy simplifies the elective surgical procedure.     

Intoxication with four synthetic pyrethroids fails to show any correlation between neuromuscular dysfunction and neurobiochemical abnormalities in rats

The neurological effects of four synthetic pyrethroids resmethrin, permethrin, cypermethrin, and deltamethrin have been investigated in the rat to establish whether there is a correlation between the clinical-functional status of the animal and peripheral nerve damage as measured biochemically. Neuromuscular dysfunction was assessed by means of the inclined plane test and peripheral nerve damage by reference to beta-glucuronidase and beta-galactosidase activity increases in nerve tissue homogenates from treated and control animals. A transient functional impairment was found in animals treated with any one of the four pyrethroids tested and in all cases this was maximal at the end of the 7 day subacute dosing regimen. Significant increases in beta-glucuronidase and beta-galactosidase were found 3-4 weeks after the start of dosing in the distal portion of the sciatic/posterior tibial nerves from permethrin, cypermethrin, and deltamethrin treated animal; but no changes were found in remesthrin-dosed animals. It is concluded therefore, that there is no direct correlation between the time-course of the neuromuscular dysfunction and the neurobiochemical changes. This suggests that these pyrethroids have at least two distinct actions--a short-term pharmacological effect and at near-lethal dose levels a more chronic neurotoxic effect that results in sparse axonal nerve damage.     

Hierarchic organization of globular proteins

In previous work, globular proteins of known structure were shown to be iteratively subdivisible into a hierarchy of disjunct, contiguous-chain regions, ranging in size from whole protein monomers down to individual helices and strands (1, 2). We now report the results of a similar analysis performed on a set of 1000 simulated chain folds that were generated by a method due to Schulz (3). The organization of these simulated proteins was found to be similar to that of authentic molecules. This control study strengthens earlier evidence suggesting that hierarchic architecture is a ubiquitous attribute of protein chain folds.