PubMed Health⌕ Search

Biomedical subjects

T V Davydova

Publications and source records attributed to T V Davydova.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

[Morpho-functional characteristics of the optic nerve of the steppe turtle Agrionemys horsfieldi].

The optic nerve of the tortoise Agrionemys horsfieldi contains about 400,000 fibers (90% unmyelinated and 10% myelinated ones). the diameter of unmyelinated fibers varies from 0.3 to 1.1 mu, mean value being equal to 0.5 mu; fibers with a diameter 0.4-0.7 comprise 77%. The diameter of myelinated fibers varies within 0.3-3.0 mu, average value being 0.5-0.8 nu; fibers with a diameter 0.5-0.9 mu amount to 62%. Electrogram of the optic nerve consists of two components which are equal in their amplitudes. These components presumably reflect summary firings of modal groups of unmyelinated and myelinated fibers. The velocity of propagation of excitation along the fibers producing the first component is equal to 1.3 m/sec, wheras that in fibers producing the second component - to 0.5 m/sec. The data obtained are compared with those related for the other tortoise - Emys orbicularis.

Animals↗
PubMedDate not supplied

[Use of substance P fragments in experimental treatment of alcoholism].

Experiments on unbred male mice demonstrated qualitative differences in the pharmacological effect of substance P fragments (P1-4 and P5-11) injected intraperitoneally in a dose of 250 mcg/kg. Fragments P1-4 and P1-4 dodecylamide on the one hand, had a positive effect on the level of motivation which was displayed by lesser consumption of alcohol by the animals, and, on the other, possessed immunocorrective properties manifested by restoration of macrophage phagocytic activity and immune response to sheep erythrocytes, which were impaired by chronic alcoholic intoxication. Fragment P5-11 had no effect on alcoholic motivation and produced a directly contrary action on the immune system, it inhibited the formation of antibody-forming cells.

Alcoholism↗
PubMedDate not supplied

[The use of vitamins A and E for the correction of immunologic disorders in chronic alcoholic intoxication].

In experiments on BALB/c mice it has been shown that in chronic alcoholic intoxication the immune response to sheep red blood cells is drastically suppressed. Oral administration of vitamin A or E oil solution in doses 3000 and 5 IU/day, respectively, during 3 days, led to correction of the immune response to sheep red blood cells disordered as a result of alcoholic intoxication.

Alcoholism↗
PubMedDate not supplied

[Further study of immuno-correcting properties of vitamins A and E in experimental chronic alcoholic intoxication].

The experiments conducted on guinea pigs have shown that chronic alcohol poisoning induced by daily oral intake of 1 ml of 25% ethanol solution during a month has brought to suppression of the T-system immunity. Vitamin A used during 3 days in a dose of 30,000 IU results in partial normalization of the immunological parameters, while vitamin E given during 3 days in a dose of 50 IU provides absolute normalization of the immune status.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Vitamin A: effect on phagocytosis and neutrophil bactericidal systems under normal conditions and in various pathological states].

Effect of vitamin A on phagocytic activity and the state of bactericide system involving myeloperoxidase and cationic proteins was studied in neutrophils from peripheric blood of volunteers and of the patients with chronic pneumonia and lung cancer. Vitamin A was administered per os within 1 week at a daily dose of 500,000 IU. In healthy persons vitamin A, not affecting the ability of neutrophils to capture and lyse microbes, activated myeloperoxidase and increased the cationic proteins content. Under conditions of lung cancer the vitamin did not alter any patterns of phagocytosis studied. Vitamin A did not affect the capture and lysis of microbes in chronic pneumonia but increased distinctly the myeloperoxidase activity in neutrophils, impaired during the disease, and normalized partially the content of cationic proteins.

Adolescent↗
PubMedDate not supplied

[Morphofunctional characteristics of the optic nerve of the turtle Testudo graeca].

Electron microscopic investigation indicates that in T. graeca the optic nerve consists of about 216,000 fibers of which 11% are myelinated and 89%--unmyelinated ones. The diameter of myelinated fibers varies within 0.2-2.5 mu, the main bulk of fibers (42%) having the diameter 0.5-0.7 mu. The diameter of unmyelinated fibers varies between 0.1 and 0.35 mu. With respect to their diameter, 8% of the fibers of both groups overlap each other. During electrical stimulation of the optic nerve, action potential in the latter is recorded which consists of two high amplitude components. The first component (propagation velocity 1.5 m/sec) presumably corresponds to conduction of excitation along myelinated fibers, the second one (propagation velocity 0.6 m/sec)--along unmyelinated fibers.

Animals↗
PubMedDate not supplied

[Effect of vitamin E on T and B lymphocyte numbers in the peripheral blood and various indicators of nonspecific immunity].

It has been shown in experiments on mice, guinea-pigs and rabbits that additional administration to the animals of vitamin E provokes an increase in the content of T lymphocytes in the peripheral blood without exerting any effect on the content of B lymphocytes. Such an addition also markedly stimulates natural killers of spleen lymphocytes. The complementary, lysozyme and nonspecific bactericidal activity of blood serum remains unchanged in this case.

Animals↗
PubMedDate not supplied

[Further study of the role of vitamin A in immunologic reactions (observations in volunteers)].

Studies made on volunteers who received vitamin A for a week have demonstrated that the content of peripheral blood lymphocytes increased, which was followed by a relative and absolute increase in the content of B lymphocytes and a rise in the number of T cells in the peripheral blood. An increase in the complementary activity of the blood serum and an increase in IgA content in it were also recorded. After a month the majority of the parameters under study returned to normal.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Changes in the retinotectal system of the tortoise Testudo graeca following enucleation].

Electrophysiological and electron microscopic studies have been made on degeneration in the optic nerve and midbrain tectum after enucleation of the tortoise T. graeca. It was found that intensive degeneration of terminals which follows "dark" type (1/2--1 month after enucleation) corresponds to degeneration of myelinated fibers. Mass degeneration of the "light" type is associated with degeneration of unmyelinated fibers, being observed 1 1/2--2 months after the enucleation. The main bulk of fibers and terminals degenerates at the period of 4--4 1/2 months. Changes in functional characteristics of the evoked potentials (EP) follow morphological ones and consist in an increase of the interval between the stimulus and the peak of EP components, as well as of the decrease of the amplitude of the EP. Within 4--4 1/2 months, both EP components disappear almost simultaneously.

Animals↗
PubMedDate not supplied

[Effect of vitamin A on immunological status of patients with chronic pneumonia].

Effect of vitamin A on some patterns of specific and unspecific immunity was studied in patients with chronic pneumonia. The vitamin was administered into the patients during 7 days at a daily dose of 500,000 IU. Administration of vitamin A was found to stimulate several immunological patterns: content of T- and B lymphocytes in peripheral circulation as well as IgG and IgM blood serum were increased. After the vitamin A treatment the cellular immunity was also stimulated, involving the activation of lymphocyte blast transformation with PHA and the increase in exhibition of skin reaction towards PHA. In response to vitamin A administration activation was observed of unspecific bactericidal, and complement activities in blood serum as well as of the myeloperoxidase activity in leukocytes of peripheral circulation. Administration of vitamin A into the control patients within a week at a daily dose of 10,000 IU did not alter the immunological patterns studied.

Antibody Formation↗