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Biomedical subjects

G Csaba

Publications and source records attributed to G Csaba.

At least 343 records · Page 19Linked to original sources
PubMed1985

Influence of receptor formation and receptor movement inhibitors on hormonal imprinting in cell culture.

Hormonal imprinting takes place at the first interaction of the cell with the adequate hormone, and exerts a lasting influence on cellular binding capacity and functional response over many subsequent cell generations. Hormonal imprinting can also be induced in cell lines. In a Chinese hamster ovary (CHO K1) cell line, inhibitor of endocytosis and cellular protein synthesis inhibited hormone binding in themselves, and in cultures preexposed to TSH they inhibited imprinting by TSH in a dose-dependent manner. The protein synthesis inhibitor cycloheximide and the microfilament de-organizing agent cytochalasin-B inhibited imprinting by TSH to a greater degree than all other inhibitors tested, indicating that apart from cellular binding capacity, unimpaired cellular protein synthesis and microfilament activity are essential prerequisites of hormonal imprinting.

Animals↗
PubMed1985

Influence of hormone treatment applied or begun in different phases of the cell cycle on hormonal imprinting in Tetrahymena.

Primary exposure to a hormone (hormonal imprinting) alters--in the case of the Tetrahymena increases--cellular response to re-exposure(s) to the same hormone. The intensity of hormonal imprinting depends on the phase of the cell cycle in which the primary exposure has taken place. The effect of imprinting was greater on the cells exposed to the hormone in phase G1 than on those exposed in phase S or G2. The response pattern of the progeny generations corresponded to that of the primarily exposed (imprinted) ancestor cell, irrespective of their own pre-exposure in phase G1, G2 or S of their cycle.

Animals↗
PubMed1985

Influence of low and high temperature on diiodotyrosine imprinting in Tetrahymena.

Hormonal imprinting takes place at the primary interaction between target cell and hormone, and alters cellular response to the hormone for lifetime (at the unicellular level in many subsequent generations). Imprinting induced in Tetrahymena cells by diiodotyrosine at the optimum temperature of 25 degrees C took effect on re-exposure to the hormone at 25 degrees C and 15 degrees C, but failed to take effect if the cells were first exposed to the hormone at 15 degrees C or 32 degrees C.

Animals↗
PubMed1985

The ultrastructure of adrenocortical (interrenal) cells of normal and ACTH-treated chick embryos.

The ultrastructural features of the interrenal cells have been studied in 20-days-old chick embryos following the administration of adrenocorticotropin (ACTH), on the 8th or 15th day of incubation. The interrenal cells of normal embryos contain more SER than RER, mitochondria with tubular cristae, lipid droplets and Golgi complex. Adjacent cells had numerous regions of pentalaminar fusion and intermediate junctions. Neither a precise organization of medullary tissue in relation to interrenal tissue nor any structural differences between interrenal cells were found. Changes in the fine structure of the interrenal cells following ACTH treatment were extensive. The organelles that are known to be involved in the biosynthesis of steroids displayed structural modifications. These were mainly SER, mitochondria, and lipid droplets. Changes were also noticeable in the Golgi complexes, membrane-bound dense bodies (especially in 15 days treated embryos). These results indicate the well developed organelles in the interrenal cells of 20-days-old embryos, and their capacity to respond to ACTH stimulation as early as the 8th day of embryogenesis.

Adrenal Glands↗
PubMed1985

Imprinting, digoxin uptake and storage in Tetrahymena.

Tetrahymenas after a single exposure to high concentration of digoxin, release glycoside into the culture medium even three days after removal of the drug. After nine or fifteen days, however, this effect subsides. Re-administration of digoxin causes the digoxin consumption (storage) of Tetrahymenas to increase. This observation indicates that the digoxin imprinting previously demonstrated in mammals occurs also in Tetrahymena. The experiments raise the possibility that also Tetrahymenas are capable of producing a digoxin-like substance detectable by radioimmunoassay.

Animals↗
PubMed1985

Investigation of gonadotropin-thyrotropin overlapping and hormonal imprinting in the rat testis.

In the neonatal period both gonadotropin and thyrotropin increase the weight of the testis, influence considerably the diameter of the contorted tubules increase the occurrence of Sertoli cells and decrease the number of spermatogonia. These phenomena can still be observed at the age of seven days but they disappear by the age of six weeks; at that time the hormones decrease the weight of the testis. One single TSH treatment administered in the neonatal period considerably increased the weight of the testis and the diameter of the channels when investigated at the age of six weeks. Gonadotropin had none of these effects. The phenomenon of imprinting could be proved as in the animals pretreated with TSH, gonadotropin given at the age of six weeks decreased the weight of the testis and both hormones decreased the diameter of the seminiferous cords.

Animals↗
PubMed1985

Selective and/or overlapping effect of pituitary hormones (thyrotropin, gonadotropin) on serum thyroxin and testosterone level in newly hatched cockerels.

Follicle-stimulating hormone and thyrotropin administered perinatally to cockerels have an overlapping effect on the testis and on the thyroid gland. Both hormones when given in one single dose considerably increased the serum level of both thyroxin and testosterone. In the case of chronic treatment performed in the perinatal period, the thyroxin level will similarly increase, though to a smaller extent, while the testosterone level decreases. The experiments studying the direct effect on hormone secretion proved the overlapping effect of the hormones in the perinatal period.

Animals↗
PubMed1985

Cyclic changes of concanavalin-A binding sites in Tetrahymena cell membrane.

Tetrahymena pyriformis GL cells were incubated with Con-A and HRP to demonstrate the localization of cell membrane sugar-components. Membrane sugar-components were found to be mobile and to change their localization periodically during the cell cycle. Highest Con-A binding occurred during division at the transition between G1 and S phases. The cap formation shown by the sugar components is a physiological phenomenon in Tetrahymena occurring mostly periorally and to a lesser extent aborally.

Animals↗
PubMed1985

Internalization and heterochromatic localization of 3H-di-iodothyrosine (T2) in the unicellular organism Tetrahymena and rat thymocytes.

Diiodotyrosine (T2) binds in Tetrahymena to ciliary membranes and enters the cell by endocytosis and also by other means (diffusion?). It can be found in the nucleus within, always in heterochromatic localization. The mitochondrial localization is also characteristic. In rat lymphocytes T2 is present in the cytoplasm independently from vesicles and it appears in the nucleus later than in Tetrahymena but invariably in heterochromatic localization. It can also be seen in the chromosomes of mitotic cells.

Animals↗
PubMed1985

The damaging effect of diethylstilboestrol and allyloestrenol in the chick embryo.

After diethylstilboestrol (DES) but in particular after allyloestrenol (AE) treatment, an increased mortality of chick embryos was observed. After DES-treatment a glandular-cystic hyperplasia of the oviduct, persistence and hypertrophy of the right ovary, and pseudohermaphroditism occurred. AE caused rectal and ureteral disorders. Although there are principal differences in sexual differentiation between mammals and birds, our results suggest that the use of AE for the protection of human pregnancies requires caution.

Allylestrenol↗