Biomedical subjects
Publications and source records attributed to G Csaba.
Under the effect of the recently discovered parathyroid hormone, gamma-L-glutamyl-taurine (Glutaurine) growth of thymus cultures increased in all tested age groups. Epithelial growth was prominent and signs of activation of the macrophage cells appeared. In cell cultures the nuclei and nucleoli increased in size.
In the one-day old chicken, the organs of endodermal origin, these the thymus, trachea, lung, and intestine take up significantly more iodine than the muscles which are of mesodermal origin. The thymus shows an especially high iodine incorporation, amounting in absolute values to that of the thyroid gland. An organ accumulates the more iodine, the closer to the thyroid its anlage is situated and vice-versa.
Explore the source record for details and available documents.
Earlier experiments demonstrated that a membrane pattern of Protozoa behaves as a receptor with respect to hormones of higher organisms. This raised the possibility that some selection or strengthening of this unspecific patter is involved in the evolution of the specific membrane patterns of the individual cells of higher organisms. In the present experiments, as a result of continual histamine treatment, the phagocytotic ability of a population of Tetrahymena was increased more intensely than after a single histamine treatment. The phagocytotic rate remained high for some time after the animals were returned from histamine-containing to normal medium. Thus, from the experimental data, it appears likely that as the hormone appears, selection becomes involved in the proliferation of cells possessing receptors. This observation might not only be of phylogenetic interest, but could also be relevant in receptor maturation as manifested in ontogenetic membrane differentiation.
Explore the source record for details and available documents.
Cytoplasmic and nuclear incorporation of 125I triiodothyronine by thymic lymphocytes has been demonstrated by electron microscopic autoradiography. Incorporation was significantly more pronounced in the newborn than in the adult age. The information emerging from the experime,tal observations contributes further evidence to the more precise interpretation of receptor maturation.
Explore the source record for details and available documents.
Having applied the picric acid-bromphenol blue (BPB) and the phosphomolybdic acid-benzidine (PMA-B) methods--the first method detecting the total histone content, the second one only free histones--we have found that cell nuclei of the rat embryos permanently contain histones, nevertheless, in such a pattern that the free histone appears only at a well-defined stage of embryogenesis. Strong PMA-B reaction is observable in the nuclei of some mesenchymal cells and in the reorganizing somites' cell nuclei of the 13-day-old embryo as well as in the hemopoietic elements of the 15- and 17-day old embryos' liver. Within nuclei of the red blood cells of the 13-day-old embryo an extremely intense reaction is seen which then disappears till the 15th day, while the BPB reaction shows a gradual intensification up to the neonatal age. The experiments support the former model of one of the authors for a histone-nonhistone control of ontogenesis.
In agreement with earlier results, follicle stimulating hormone (FSH) enhances spermatogenesis in the snail. Thyreotropic hormone (TSH), which resembles FSH in its chemical structure, acts in the same way as does adrenocorticotropic hormone (ACTH) to a lesser extent. As opposed to FSH, TSH and ACTH clearly increased the number of mature egg cells. The experiments support the view that the gonad cells of the snails respond to vertebrate hormones, and that the hormones have overlapping effects at this level.
In short-term tissue cultures dibutyryl cAMP inhibits the cortisone-induced degranulation of mast cells. The effect of methylxanthine was found to be similar but developed at a slower rate. The increase of cAMP level also affected the maturation of mast cells, as the ratio of cells of mixed granulation increased, compared to the alcian blue- and safranin-present model inhibited degranulation.
The mast cell population is heterogeneous concerning its amine precursor and amine uptake. The immature cells incorporate amine precursors, but in more advanced stages of their maturation they take up only 5-HTP. The mature cells do not take up precursors only 5-HT. The thyroid gland and heart muscle mast cells take up the highest amount of 5-HT; this may be related with some specific function of the mast cells in these two organs. Neither of the mast cells would take up histamine, the compound is synthetised by the cells.
Explore the source record for details and available documents.
The heterogeneity of the mast cells localized in various organs has been demonstrated by histochemical determination in their indole amine and histamine content. The strongest amine reaction was found in the mast cells in the mesenterium and peritoneal fluid where their maturation occurs. The reaction of the subcutaneous connective tissue is weaker; in the thyroid gland the reaction is weak as well as diffuse. In the thymus the mast cells localized along the vessels give a strong histamine reaction. The experiments support previously published data concerning the heterogeneity of mast cell populations.
Treatment of neonatal rats with a single does of gibberellin had a notable influence on certain endocrine indices in adulthood. It accelerated the growth rate of the animals and produced weight increase of thyroid, ovary and adrenals as well as of the blood Ca-level, but reduced the weight of the testis.
Rats treated once with glucosamine at neonatal age show a long-lasting decrease in blood sugar level, and a permanent increase in insulin level, as well as a decrease in body weight. Glucuronic acid and mannose give rise to similar significant changes which were quantitatively less than the changes seen following pre-treatment with glucosamine. Taken together with earlier experiments, it seems likely that receptors are "plastic" at neonatal age and may be influenced by substances resembling the hormone or inducer, but differing from these to some extent.
Gonadotropin or TSH treated newborn animals reacted to TSH treatment in their adult age in a lesser degree than control ones. This suggests the plasticity of hormone receptors and the possibility of their deformation in neonatal age.
Explore the source record for details and available documents.
Dibutyril cAMP and the cPDE-inhibitor theophylline both enhance the phagocytotic activity of Tetrahymena. Theophylline and cAMP-activating histamine are synergistic. It follows that the cAMP-adenylcyclase system functions in the unicellular animal Tetrahymena.