Catalase Test as an Aid to the Identification of Enterobacteriaceae

Although the catalase test has been used for many years for rapid differentiation of the genera of gram-positive organisms, little has been said about its use in the family Enterobacteriaceae. It was further noted that a wide variety of methods exist for the execution of the catalase test, that there is no universally accepted strength specified for the hydrogen peroxide, and that no gradations for the vigor and speed of the reaction have been mentioned. Under the conditions of the clinical laboratory, we have developed a simple, rapid, and accurate method for the catalase test that has been of great value as an aid in the identification of the Enterobacteriaceae. With 3% H(2)O(2), it was observed that Serratia, Proteus, and Providencia were vigorous catalase reactors. Only Salmonella and rare Escherichia, Enterobacter, and Klebsiella isolates were moderate catalase reactors. Escherichia and Shigella strains were mostly nonreactive, with less than one-third weekly (+) reactive, whereas most Enterobacter strains tended to be weakly reactive. Klebsiella strains were divided equally between nonreactive and weakly reactive. In practice, this test was also of great value in discerning nonpigmented Serratia cultured from the hospital environment and in detecting mixed flora containing nonspreading Proteus.     

Polyelectrolyte Flocculation as an Aid to Recovery of Enteroviruses from Oysters

A simple and rapid method for recovering enteroviruses from oysters is described. A polycation sewage flocculant promoted cohesion of oyster solids and thereby aided separation of these from the viruses. Recovery of 80 to 100% of experimentally inoculated virus was achieved, and the suspension or extract obtained could be inoculated directly into tissue cultures or concentrated first for greater sensitivity.     

Needle Biopsy as an Aid to the Precise Diagnosis of Intrathoracic Disease

The place of needle biopsy of the lung and pleura in the diagnosis of intrathoracic disease was assessed by means of an analysis of the results of this procedure in 78 cases involving 111 separate biopsy attempts. The Vim-Silverman needle was used throughout. Needle biopsy of the lung, restricted to cases with localized radiological lesions peripherally situated and suggesting neoplasm, yielded a specific diagnosis in 29 of 48 patients. The comparison with other diagnostic aids, bronchoscopy, sputum cytology and scalene node biopsy, was favourable, at least in the case of peripheral tumours. There were eight complications, only three of which were of significance. Needle biopsy of the pleura proved to be a less rewarding procedure, a specific diagnosis being obtained in only seven of 30 cases. There were, however, no serious complications with this latter procedure. It was concluded that needle biopsy is of some value as a relatively safe addition to diagnostic techniques in chest disease.     

Stereotaxis in human neurophysiology

This article is devoted to the basic concepts and provisions of the scientific school of Academician N.P. Bechtereva, such as the complex method to study the human brain, application of long-term intracerebral electrodes, and the stereotactic method (computer stereotaxis), as well as their development associated with the introduction of modern intrascopy (tomography) methods. The relationship between multiple electrode methods and studies of pathophysiological mechanisms of Parkinson’s disease, temporal lobe epilepsy, and various forms of obsessive-compulsive syndromes is considered.