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Biomedical subjects

V S Nikitin

Publications and source records attributed to V S Nikitin.

At least 19 recordsLinked to original sources
PubMed1987

[Effect of thiamine and its antimetabolite oxythiamine on the proliferative activity of carcinosarcoma Walker 256 cells].

The microscopic studies of tumours from rats injected with thiamine at a dose of 20 mg/kg for 5 days have shown that sites of hemorrhages and necrosis are considerably more extensive than in tumours of control animals. Injections of the same doses of oxythiamine increase the rate of pathologic mitoses in tumour cells and decrease the tumour weight by 45%, limit the synthesis of thiamine diphosphate and inhibit the transketolase activity in tissues.

Animals↗
PubMed1983

[Alkaline phosphatase and transketolase activity during immunogenesis in the lymphoid organs of rats with vitamin B1 deficiency caused by oxythiamine].

A study was made of the effect of different doses of hydroxythiamine on activity of alkaline phosphatase and transketolase in rat spleen and thymus during primary and secondary administration of human gamma-globulin. Immunization of rats significantly raised alkaline phosphatase activity in both organs. Administration of a large single dose of hydroxythiamine (400 mg/kg bw) reduced transketolase activity in the thymus and spleen in both immunized and non-immunized animals and did not change alkaline phosphatase activity in these organs.

Alkaline Phosphatase↗
PubMedDate not supplied

[Various analogues of the second-signal behavior in monkeys during their symbolic "description" of properties of planimetric figures].

An attempt was made of experimental simulation of some components of the "second-signal" (verbal) behavior in rhesus monkeys (Macaca mulatta) under conditions of their "dialog" with a computer. Three monkeys were trained to perform manipulative actions on keyboard simulator to "describe" the properties of planimetric figures. For the period of research, the monkeys have learned to reproduce combinations of two symbols ("bigrams") that were used by them for a "description" up to 12 geometrical figures of various sizes. The data obtained indicate that rhesus monkeys are able not only to generalize the properties of a certain class of visual images at the perceptual level but also to use symbols for the description of these generalized properties.

Animals↗
PubMedDate not supplied

[The comparative action of relanium and oxytocin on higher nervous activity in lower monkeys].

Effects of relanium and oxytocin on higher nervous activity was studied in four rhesus monkeys (Macaca mulatta) and two baboons (Papio hamadryas). During observation of the animals in enclosure tranquilizing effect was seen only after relanium administration. Under the same conditions oxytocin practically did not change the general behaviour pattern of monkeys. However, steady behavioural transformations were observed under the conditions of competitive food-procuring behaviour and during the operant goal-directed reaction. Decreasing aggressiveness of dominants oxytocin in contrast to relanium had no negative effect upon their general motor activity and sensory perception. Differences in effects of the tranquilizer and the peptide were seen also at the unit activity level of the neurons. The first drug lowered the unit activity level and the degree of the functional connections in neuronal populations in a number of cortical structures. Administration of the second one led to selective shifts of the unit activity mainly in the frontal cortex of the monkeys.

Animals↗
PubMedDate not supplied

[A comparative physiological study of the generalization function in primates].

Fundamental rules of the generalization function formation and development were formulated on the basis of comparative analysis of visual discrimination, summarizing and abstraction in the representatives of various primate subfamilies. It was established that monkeys and apes (Macaca mulatta, Cebus apella, Pan troglodytes) learning to define such abstract characteristic as relative size of visual pictures of natural and geometrical objects were able to use previously remembered rules elaborated under the solving of other visual tasks. Learning processes were realized more affectively, if the pictures of natural objects were represented to the monkeys. The comparison of generalization processes in monkeys and apes revealed multilevel organisation of the processes in apes. The latter showed high level of ability to operate with abstract ideas elaborated previously in the course of the experiments.

Animals↗
PubMedDate not supplied

[Morphological characteristics of cellular elements in the focus of posttraumatic inflammation in thiamine deficiency].

The influence of vitamin B1-deficiency on the ultrastructure of the cellular elements in the focus of aseptic inflammation in the skeletal muscles was studied in white mice, 2 and 3 days after the infliction of a mechanical trauma. Food B1-hypovitaminosis was induced by keeping the animals on a thiamine-deficient ration during 30 days. Oxythiamine hypovitaminosis was simulated by subcutaneous injections of vitamin B1 antimetabolite--oxythiamine, in a dose of 10 mg/kg, every 12 h, during 10 days. Both types of hypovitaminosis induced similar reactions of the cellular elements. The volume fraction of lysosomes and phagosomes in the macrophage cytoplasma decreased, the volume density of mitochondria increased, differentiation of fibroblasts was delayed. No significant changes were detected in the ultrastructure of neutrophilic granulocytes, eosinophils and lymphocytes. Decrease of macrophage phagocytic activity is one of the main factors in the mechanism of delay of necrotic mass resorption and inhibition of the following development of reparative processes.

Animals↗