Protective reaction of the myocardium in poisoning

Intensive synthesis of collagen-like substance was revealed in the rabbit myocardium during experimental diphtheria intoxication. It was more marked in the right ventricle 24 hours after the injection of diphtheria toxin. Since similar changes (the substance was mainly formed around blood vessels) have been observed in other cases of toxic myocardial alterations (i.e. ethanol intoxication, injection of pharmacological agents, etc.), it can be assumed that it is a standard protective reaction of the altered heart to the penetration of toxic agents from the blood into the myocardial tissue.     

Suppression of the immune response by Shigella in experimental influenza infection in mice

Experiments in mice have demonstrated that in the presence of influenza infection the suppressing effect of virulent shigellae on the secondary humoral and cell-mediated immune response is enhanced. Under such conditions avirulent shigellae can also show suppressing effect which is usually absent in these organisms.     

Circulating immune complexes in the pathogenesis of recurrent erysipelas

The dynamics of circulating immune complexes (CIC) in comparison with the level of SH-groups of serum deproteinate and other characteristics of cell-mediated and humoral immunity (the reaction of the inhibition of antibodies, the levels of T-cells and their main subpopulations) was studied in 103 erysipelas patients and in 46 persons having had the disease at the acute period of this infection and at the periods between relapses. The elevated levels of CIC and SH-groups of serum deproteinate were found to be directly correlated with the inhibition index. The study showed that, as a rule, in patients with the elevated level of CIC the frequently relapsing form of erysipelas, accompanied by the formation of relative hypersuppressor-type secondary immunodeficiency and by a decrease in the functional activity of dermal macrophages, was observed.     

The Relationship between the Structure of the Tick-Borne Encephalitis Virus Strains and Their Pathogenic Properties

Tick-borne encephalitis virus (TBEV) is transmitted to vertebrates by taiga or forest ticks through bites, inducing disease of variable severity. The reasons underlying these differences in the severity of the disease are unknown. In order to identify genetic factors affecting the pathogenicity of virus strains, we have sequenced and compared the complete genomes of 34 Far-Eastern subtype (FE) TBEV strains isolated from patients with different disease severity (Primorye, the Russian Far East). We analyzed the complete genomes of 11 human pathogenic strains isolated from the brains of dead patients with the encephalitic form of the disease (Efd), 4 strains from the blood of patients with the febrile form of TBE (Ffd), and 19 strains from patients with the subclinical form of TBE (Sfd). On the phylogenetic tree, pathogenic Efd strains formed two clusters containing the prototype strains, Senzhang and Sofjin, respectively. Sfd strains formed a third separate cluster, including the Oshima strain. The strains that caused the febrile form of the disease did not form a separate cluster. In the viral proteins, we found 198 positions with at least one amino acid residue substitution, of which only 17 amino acid residue substitutions were correlated with the variable pathogenicity of these strains in humans and they authentically differed between the groups. We considered the role of each amino acid substitution and assumed that the deletion of 111 amino acids in the capsid protein in combination with the amino acid substitutions R16K and S45F in the NS3 protease may affect the budding process of viral particles. These changes may be the major reason for the diminished pathogenicity of TBEV strains. We recommend Sfd strains for testing as attenuation vaccine candidates.     

Information properties of neuron assemblies

Calculations are made of information parameters of neuron nets with binary plastic synapses of Hebb and Albus which are able to form and produce neuron assemblies. It has been shown that for such neuron nets Hebb synapses are more effective than Albus synapses.     

Dynamic changes in arylsulfatase activity in the initial period of acute focal myocardial ischemia in an experiment

The increase in arylsulphatase activity in the ischemic zone has been shown by histochemical method in progressing acute myocardial ischemia. The increase in the enzyme activity in a so-called "intact" zone was less marked.     

Information characteristics of neuronal and synaptic plasticity

Informational losses in neuronal nets(NN) with plastic elements were estimated. These losses are related with 1) transition from "complicated" decoding when from the modification state of such elements information of the whole set of recorded elements is extracted to "simple" decoding natural of NN functioning when information is extracted independently for individual events; 2) uncertainty concerning NN structure, if at decoding in one of the modification states the neuron reactivity totally or the weight of plastic synapse equals zero. After the transition from complicated to simple decoding these losses for gradual plasticity are so great that NN with such plasticity has no advantages in informational capacity as compared to the binary one. These losses are absent for plasticity of Olbus type. They are relatively high for neuronal plasticity of Hebb type. For Hebb synapses their value essentially depends on the net parameters.     

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.     

Memory model based on the plasticity of inhibiting neurons

A stochastic memory model based on the net of excitatory and inhibitory neurons is considered. Its learning ability is due to a decrease of the reactivity of inhibitory elements. Information capacity of such neuron net was estimated in relation to its structure parameters. It has been shown that in the definite range of their change the information capacity of the net under consideration significantly exceeds that of the neuron net with the memory based on the plasticity of excitatory elements.