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Biomedical subjects

V S Nikitin

Publications and source records attributed to V S Nikitin.

11 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↗
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↗
PubMedDate not supplied

[Posttraumatic regeneration of the skeletal muscles in certain forms of hypovitaminosis B1].

Light microscopy was employed to study the development of posttraumatic aseptic inflammation and subsequent regeneration in the affected musculus soleus in different patterns of hypovitaminosis B1. Alimentary deficiency of thiamine entailed pronounced retardation of the post-traumatic inflammation. The growth of macrophage density and formation of the pool of the regenerating cells were also retarded. On day 21 the regeneration pool showed an elevated content of the connective tissue. During long-term administration of oxythiamine in a dose of 10 mg/kg with a 12-hour interval, the development of the inflammatory response was marked by similar alterations, but the formation of muscle fibers and connective tissue proceeded more uniformly. A single administration of oxythiamine in a dose of 200 mg/kg did not bring about any substantial impairment of the early stages of regeneration. The alterations observed can be associated with different degree of inhibition of the activity of TDF-containing enzymes and derangement of the function of the nervous system.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗