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Biomedical subjects

B V Aleshin

Publications and source records attributed to B V Aleshin.

At least 19 recordsLinked to original sources
PubMed1985

Effect of thymus on the thyroid and pituitary thyrotropic function.

Thymus inflammation induced in infantile guinea pigs and rabbits by administration of melted paraffin drops into the thymic parenchyma resulted in enhancement of the thyroid functional activity. Thymosin injections provoked an identical effect. In both variants of these experiments the pituitary thyrotropin level remained within the norm. Hence, the pituitary thyrotropic function as in thyrotoxicosis lost the ability of response to enhancement of the thyroid hormone production. This result suggests that the cause of disorganization of the negative feedback between the thyroid and the pituitary thyrotropic function might be attributed to enforcement of the stimulated thymus secretory activity.

Animals↗
PubMed1984

[An inhibin-like factor in the testes of fetal and newborn rats].

A factor of protein nature that inhibits the proliferation of gonocytes and, probably, their ingress into meiosis and stimulates the development of some components of the blood-testicular barrier was isolated from the testis of 19-20-day-old fetuses and young rats of the first two weeks of life. It is assumed that the inhibin-like factor is formed in the testicular network. The time at which the receptors for the factor under discussion may occur in the cells of the testis of Wistar rat fetuses is discussed.

Animals↗
PubMed1983

[Parafollicular cells in the regenerating thyroid gland].

Ten days after partial thyroidectomy (excision of the lower half of the thyroid left lobe) made in mature male rabbits, functional activity of thyrocytes markedly rose. That was the organism compensatory reaction to the decreased thyroid hormone production due to the enhancement of the pituitary thyrotropin secretion. However, parafollicular cells detected by the Sawicki method underwent reduction in the number and size, which was fairly appreciable in the regenerating thyroid lobe and insignificant in the lobe left intact. This reduction is probably caused by the fact that secretory activity of parafollicular cells is stimulated by sympathetic impulses, whereas in the regenerating thyroid, there prevail the parasympathetic effects.

Animals↗
PubMed1983

[Sex differences in the development of the thyroid gland in human prenatal ontogeny].

A comparative study of the thyroid gland development in the human male and female embryos and prefoetuses was carried out. The development of incretory part of the testicles was shown to occur earlier than the differentiation of follicles in the thyroid gland and the appearance of colloid in it. Sexual differences were noted in the appearance of follicles, connective tissue, nerve fibres in the thyroid gland (earlier in the male foetuses). The processes of organ differentiation in the male foetuses were more active than in the female ones during the whole prenatal period of development. A suggestion is put forward that the sexual hormones of embryonic testicles influence the thyroid gland differentiation.

Cell Differentiation↗
PubMed1982

[Mechanism of androgenopoiesis disorder in stress].

Experiments on pubertal male rabbits were made to study the effect of prolonged stress (daily one-hour immobilization and electrocutaneous stimulation for a fortnight) on hormonal and structural gonadal function. The prolonged action of stress was shown to result in the drastically lowered testicular androgenopoiesis. Inhibition of testosterone secretion by the tests was not determined by structural disorders of the hormone-producing Leydig cells which were functionally activated under the conditions described. This activation appears to be related to the production of steroids that are not characteristic for the activity of the intact gonads.

Androgens↗
PubMed1981

[Pathogenetic problems of goiter].

The extrafollicular growth (hyperplasia) of the thyroid parenchyma resulting in the development of epithelial goiter begins with proliferation of thyrocytes of the follicular wall (sometimes called "clear cells" and erroneously identified with the parafollicular cells or C-cells). An important role in the pathogenesis of goiter disease belongs to the transition of the thyroid parenchyma hyperplasia from the initial adaptative (compensatory) reaction which arises under conditions of thyroid hormone production deficiency into the irreversible pathological process of indefinite duration after restoration of the euthyroid state of the patient. It may be assumed that this transition results from stabilization of gradually increasing shift of protein biosynthesis in the thyrocytes towards preferential thyroalbumin formation at the expense of thyroglobulin.

APUD Cells↗
PubMed1981

[Effect of sympathetic impulses on parafollicular cells (K-cells) of the thyroid gland].

Reaction of K-cells (detectable by the Savitsky method) to stimulation of the superior cervical sympathetic ganglia or to their removal was examined in experiments on male rabbits. Stimulation of the sympathetic ganglia attained as a result of application to them of a ringlet made of solid silver wire produced a marked rise of the number and size of K-cells, with the serotonin content in the thyroid gland being significantly increased as compared to the initial level. Bilateral cervical sympathectomy entailed a reduction in the serotonin content and in the size of K-cells. In the course of hyperthyroidization the functional activity of the thyroid epithelium decreased and K-cells underwent a pronounced reduction.

Animals↗
PubMed1978

[Current problems of pathogenesis of thyrotoxicosis].

According to current concepts, thyrotoxicosis should be regarded as an autoimmune disease in which signs of a delayed type of hypersensitivity are found. The functional excitation of the thyroid gland is caused and maintained by the appearance of lymphocytes sensitized for responding to autoantigens of thyrocytes and for production of thyrostimulating autoantibodies. The course of thyrotoxicosis is aggravated by the disorder of homeostatic mechanisms which normally oppose the hyperfunction of the thyroid gland and the effect of the excess of thyroid hormones. Thus in thyrotoxicosis the disorder of immune homeostasis is accompanied by desorganization of endocrine homeostasis.

Antigen-Antibody Reactions↗
PubMed1977

[Functional and structural changes in the adrenal cortex of rabbits under conditions of chronic inflammation of the prostate gland].

Investigation of the state of the rabbit adrenal cortex under conditions of depression of the incretory activity of the testicles resulting from chronic inflammation of the prostate showed progressive hyperplasia of the reticular zone of the adrenal cortex; as to the glomerular zone, it failed to display any marked pathological changes, and the fascicular zone demonstrated some signs of hypoplasia. Thus, the normal or elevated androgen excretion observed in the experimental male rabbits, was provided by an intensified activity of the reticular zone of the adrenal cortex, despite a decrease in testosterone biosynthesis in the testes.

Adrenal Cortex↗
PubMed1976

[Catecholamine concentration in the hypothalamus following alteration of pituitary adrenocorticotropic function].

Norepinephrine, epinephrine and serotonin levels were studied in male rabbit hypothalamus and midbrain under the influence of different factors potentiating the hypophysial adrenocorticotropic function. Intensification of this adrenohypophysial function was accompanied by a certain decrease in the hypothalamic and midbrain norepinephrine level and by the appearance of epinephrine normally absent here. The role of serotonin in the regulation of the investigated pituitary function was not revealed since potentiation of this function was observed both with the lowered and with the elevated concentrations of this monoamine in the hypothalamus.

Adrenocorticotropic Hormone↗