Correlation between the rate of ethanol elimination and the psychophysiological characteristics of rats

Ethanol elimination from the blood of rats with different psychophysiological features was studied using gas chromatographic head-space analysis in the general complex of tests aimed at determination of ethanol consumption. The selection of animals with different levels of the initial alcohol motivation was performed according to modified Porsolt's method. It was shown that the initial level of predisposition to depression-like states is in a dose-dependent correlation with the high rate of ethanol elimination. This is suggested to be one of the genetic indications which promotes the formation of the initial alcohol motivation and the development of experimental alcoholism.     

Neutral alpha-mannosidase in human B- and T-lymphoid cells]

The presence of neutral alpha-mannosidase activity in normal and pathological lymphoid cells has been demonstrated. The specific activities of the enzyme in different cell types were similar with the exception of B-cells from B-CLL patients when it was a little higher. The activity of acid alpha-mannosidase was also determined in these lymphoid cells. The neutral to acid alpha-mannosidase activity ratio was different in B- and T-cells: in the former neutral alpha-mannosidase activity prevailed, whereas in the latter the predominance of acid alpha-mannosidase activity was apparent. Neutral alpha-mannosidases from pathological B- and T-cells were partially purified and their properties were investigated. In both cell types the enzyme was localized in the cytosol, was very labile and could be stabilized with Mn2+ and dithiothreitol. The enzyme was activated by Co2+ and inhibited by Zn2+ and EDTA. Swainsonine inhibited the B-cell neutral alpha-mannosidase somewhat more strongly in comparison with the T-cell enzyme.     

Catecholaminergic component of the action of a heptapeptide analog of ACTH4-10 on the open-field behavior of rats

Heptapeptide Met-Glu-His-Phe-Pro-Gly-Pro (ACTH4-10 analog) at a dose of 0.015 mg/kg failed to alter open field behaviour of rats in the first test series. The peptide abolished amphetamine-induced stimulation of the exploratory and grooming behaviour. Extinction of the rats' exploratory behaviour during second test series in the open field (7 days later) was disturbed when haloperidol or apomorphine were injected before the first test series. When the peptide was administered with haloperidol or apomorphine, the extinction tended to become normal. Heptapeptide failed to change noradrenaline, dopamine or 5-hydroxytryptamine content in the rat forebrain. However, this peptide at a concentration of 10(-4) M moderately diminished tyrosine hydroxylation velocity in the rat striatal or hypothalamic synaptosomes, the effect depending on tyrosine concentration. These data suggest the involvement of catecholaminergic component into the heptapeptide action on the behaviour of rats.     

Peculiarities of influenza infection caused by highly and poorly immunogenic strains of influenza virus

The authors studied the peculiarities of the course of experimental influenza infection induced by the administration of highly and poorly immunogenic strains of influenza virus to mice. Influenza viruses with varying immunogenic activity were obtained from the vaccine strain A/Victoria/35/72/50 (H3N2) by immunoselection modelling the process of natural selection. The administration of strains with high and poor immunogenicity to mice of the F1 (CBA X C57B1) line led to the development of acute influenza infection accompanied by reproduction of viruses in the tissue of the lungs and other internal organs. The poorly immunogenic strain 5/II-Victoria, unlike the initial virus A/Victoria/35 and its highly immunogenic variant 2/I-Victoria, is able to circulate for a long time in the organism of the infected animal causing development of chronic inflammatory processes and stimulating the formation of neoplasms. Immunogenicity is thus one of the factors determining the character of the course of experimental influenza infection. A conclusion was drawn concerning the epidemiological and aetiological importance of viruses with reduced immunogenicity and their role in the evolution of influenza virus. It is presumed that reduced immunogenicity is one of the adaptation mechanisms of aggression permitting the population of influenza virus to escape control by specific humoral immunity.     

Sequence variation in the outer-surface-protein genes of Borrelia burgdorferi

Borrelia burgdorferi is a spirochete pathogen transmitted among warm- blooded hosts by ixodid ticks. Frequency-dependent selection for variant outer-surface proteins might be expected to arise in this species, since rare variants are more likely to avoid immune surveillance in previously infected hosts. We sequenced the OspA and OspB genes of nine North American strains and compared them with nine strains previously described. For each gene, the mean number of synonymous substitutions per synonymous site and the mean number of nonsynonymous substitutions per nonsynonymous site show only a twofold excess of silent mutations. Synonymous rates vary widely along the OspB protein. Some regions show a significant excess of silent substitutions, while divergence in other regions is constrained by biased base composition or selection. The presence, in antigenically important regions of the protein, of significant variation among strains, as well as evidence for recombination among strains, should be considered in attempts to develop vaccines against this disease.      

Manifestations of influenza-virus variability during its cultivation in the system of passively immunized chick embryos]

A method of immunological actions on the influenza virus in the system of chick embryos passively immunized with isologous sera was elaborated. With the aid of the suggested method it was possible to induce in strains (with different hemagglutinin type and different degree of attenuation) the transformation of signs characterizing the virus variability in the epidemic process. Variants of the vaccine strains of the influenza virus with increased immunogenic activity and signs of antigenic "outrunning" were obtained. Experimental vaccines from these variants were nonreactogenic for humans and caused a more frequent seroconversion than the initial strain. The diagnostic agents from the variants revealed antibodies in human sera and gamma-globulin, similarly to the "new" viruses isolated from man. The theoretical significance and the aspects of practical utilization of the data obtained are discussed.     

Effect of semicarbazide on electrical and metabolic activity of visual cortical and cerebellar neurons in tissue culture

The mechanism of the effect of semicarbazide, an inhibitor of glutamate decarboxylase, the enzyme involved in the synthesis of gamma-aminobutyric acid (GABA), on electrical and respiratory activity of Purkinje cells and cerebral cortical neurons of mice was investigated in tissue culture. The action of semicarbazide on the various parameters was shown to be biphasic in character: excitation followed by inhibition. The first phase could be connected with the blocking action of semicarbazide on glutamate decarboxylase synthesis. It is suggested that predominance of the excitatory background arising as a result of blockade of systems for which GABA is the transmitter, may lead to the development of lasting depolarization of the nerve cell membrane, giving rise to the secondary inhibitory effect. This substance was shown to have a stronger effect on Purkinje cells than on visual cortical neurons. This could indicate a high content of glutamate decarboxylase in the inhibitory synapses of cerebellar cells and could be indirect evidence of the presence of more active GABA synthesis in the cerebellum. A period of 10–14 days of development in culture during which the biphasic effect of semicarbazide was maximum was distinguished for both structures. It is suggested that inhibitory synapses for which GABA is the mediator are formed early during ontogenetic development in the brain structures studied.Patrice Lumumba Peoples' Friendship University, Moscow. Research Institute for Biological Testing of Chemical Compounds, Ministry of the Medical Industry of the USSR, Moscow-Kupavna. Translated from Neirofiziologiya, Vol. 12, No. 2, pp. 138–145, March–April, 1980.