Correlations between the properties of visual cortex neurons in the cat

In acute experiments on immobilized cats 13 functional characteristics of 96 visual cortex neurons were investigated. By means of regression, cluster, and multivariate analyses, these could be divided into two subgroups with varying degrees of correlatedness. Cells of the first subgroup were more frequently characterized by their relatively central location in the visual receptive field, while those of the second subgroup were more often found at the periphery. A significant correlation was found between 11 of the properties investigated. In each subgroup, cells with more centrally localized small receptive fields had, in comparison with neurons of the peripheral visual projection, short latent periods, lower thresholds, phasic response, and brief summation; their responses varied widely in intensity, and they had greater differential sensitivity, and were distinguished by high-frequency discharges. Significant correlation coefficients between the factors studied fluctuated between 0.21 and 0.99; moreover, there were almost twice as many significant relationships in the first subgroup of neurons as in the second. The possible mechanisms of correlations between the properties of the visual cortex neurons are discussed, as well as the reasons why they differ in cells of the two subgroups, the cortex, and the lateral geniculate body.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 17, No. 5, pp. 587–596, September–October, 1985.     

The outer membrane porin from Yersinia enterocolitica in yersiniosis diagnostics

The diagnostic test system based on a species-specific antigen, pore-forming protein from the outer membrane of Yersinia enterocolitica, for yersiniosis verification by the method of ELISA has been developed and approved. The proposed ELISA test system is characterized by high sensitivity (95%) and specificity (89%) and provides a differential diagnostics of yersiniosis from other acute enteric infections with similar clinical manifestations. In comparison with the commercial diagnostics based on indirect hemagglutination reaction, which is conventionally used in clinical practice, the porin-based ELISA provides the high level (90–95%) of yersiniosis identification at early (1st week) and late (2nd–4th week) stages of infection process. It has been found that the ELISA test system reveals antibodies to the Y. enterocolitica porin in patient’s serum irrespective of the serological variant of causative agent.     

Comparative study of modifications in the immunoperoxidase and immunofluorescent methods of detecting human tissue immunoglobulins]

The comparison of the data obtained by using different modifications of the immunoperoxidase and immunofluorescent methods for detecting immunoglobulins in intestinal tissues was made. The direct immunoperoxidase method was shown to allow the quantitative study of immunoglobulin-containing cells. The direct immunoperidase method was found to be technically simpler, but the indirect and complex peroxidase-antiperoxidase methods proved to be more sensitive.     

The adhesive properties of S and R mutants of Salmonella minnesota during batch cultivation]

The study of the adhesive, surface-electrical and hydrophobic properties of S. minnesota S- and R-mutants in the process batch cultivation has revealed that the maximum values of the above parameters are characteristic of the stationary phase of culture growth and their minimum values, of the end of the lag phase. Electrophoretic mobility and adhesiveness increase from S- to Re-chemotype. The surface of Salmonella S-form is more hydrophilic, than in R-mutants which are indistinguishable in the degree of their hydrophobic properties. The heterogeneity of the populations under study with respect to the electrophoretic mobility and adhesiveness of cells has been detected.