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Biomedical subjects

A Bordeianu

Publications and source records attributed to A Bordeianu.

At least 19 recordsLinked to original sources

Digestive histochemical reactions in rats after space flight of different duration.

Different histochemical reactions were searched in the digestive tract of rats that flighted on Soviet biosatellites, 5, 7, 13, 14 and 18 1/2 days (2). Space flight decreased glycoprotein (GP) content of sublingual glands and of gastric and intestinal mucosa, and increased reactions for leucin-aminopeptidase (LAP) and acid phosphatase (ACP) of the small intestine. These responses were in relation with the duration of the flight. For searching some possible mechanism by which they occurred, same investigations were done in rats submitted at soil level to a contention hypokinesia (HK), for mimicking space flight. After HK, similar histochemical responses were founded as after the true flight. The evolution of histochemical responses paralleled the corticosterone hypersecretion, suggesting a causal correlation, but they were also the same in adrenalectomised rats. Effectory hormonal pathways are thus further to be searched, as well as a correlation with the intermediary metabolism, as a similar evolution was founded in pancreatic, insulin secreting, B cells.

Animals↗

The action of simulated and true weightlessness on the digestive tract of rats.

Rats on board the Soviet Cosmos 936 satellite for l8 1/2 days showed a decreased glycoprotein secretion from the salivary mucous glands, stomach and intestine, and an increased leucine aminopeptidase and acid phosphatase content from the small intestine. Grimelius positive cells were activated. One group of rats were centrifuged at 1 g during the flight to simulate terrestrial gravity. Some investigations have suggested that under these conditions muscular and cardiac disorders diminished. In the digestive tract the benefits of centrifugation at 1 g are minimal and limited to a few glycoprotein components. The digestive changes are probably the expression of a stress response, unrelated to weightlessness. Similar changes, concomitant with a glycocorticoid hypersecretion, were found in rats after 15 days of hypokinesia on Earth. These digestive changes persisted even in adrenalectomized rats.

Acid Phosphatase↗

The gastrointestinal tract in hypokinetic rats.

In Wistar rats kept for 15, 30 and 60 days in a hypokinetic state in special cages, alteration of some gastrointestinal glands was studied by means of histochemical and electron microscopic methods. After 15-30 days of hypokinesia, a decrease was found in the muco-polysaccharide content of the submaxillary, gastric and duodenal glands. The intestinal goblet cells appeared vacuolated. The oxyntic cells, which secrete HCl, as well as the G antral cells, which secrete gastrin, were in an active state. The hypokinetic rats exhibited increased gastric secretion. The electron microscopic aspect of the principal cells corresponded to augmented pepsin secretion. The enterocytes showed an increase in their leucine aminopeptidase, acid phosphatase and glucose-6-phosphatase content. In the submucosa of the fundus of the stomach an accumulation of eosinophils was observed. These modifications were more striking after 15 than after 30 days, and disappeared after 60 days of hypokinesia. These morphological and functional changes may be explained by glucocorticoid hypersecretion corresponding to a stress reaction.

Acid Phosphatase↗

[Significance of the AgHB and of the immune reaction in chronic hepatitis].

The authors studied 496 patients with chronic persistent or aggressive hepatitis, and active or non-active hepatic cirrhosis, and 396 non-hepatic patients. AgHB was detected in the serum by immuno-electrophoresis and by immuno-diffusion and, in the liver, by needle biopsy, using immuno-fluorescence. The liver diagnosis was made histologically. AgHB was found in 34.2% of patients, more often in chronic active hepatitis (53.7%) than in inactive forms (23.2%). This finding may be interpreted as a sign of severity, chronic aggressive hepatitis is more frequently caused by B virus and by its persistence in the liver. In all cases of chronic, aggressive hepatitis studied with AgHB in the serum, AgHB was detected in the nuclei of the liver parenchyma cells. It should be emphasized that there is no significant difference from the immunological point of view, between patients with AgHB and the others, the levels of gamma-globulin and immunoglobulin were higher in the former. The increased frequency of AgHB in the active forms of the disease compared with stabilised forms, reinforces its physiopathological, diagnostic and prognostic significance.

Antibody-Producing Cells↗

Circulatory adaptive reactions under hypergravity in normal and cold environments.

Rats subjected to various levels of +Gz acceleration exhibited an increased blood concentration of noradrenalin and adrenalin, indicative of a sympatho-adrenergic reaction. Under the same conditions, from plasma determinations, and by histochemical examination of the supra-optic nucleus, an increased antidiuretic response was noted. This response was reduced in cold environment.

Animals↗

Effect of hypergravity and hyperthermia on antidiuretic hormone secretion.

The effect of acceleration and hyperthermia on the antidiuretic hormone secretion (ADH) was investigated in rats both separately and simultaneously. The two conditions of stress elicited a rise in plasma ADH concentration in proportion to their intensity. Concomitant exposure to the two factors produced an additional effect. The parallel histochemical studies using methods for demonstrating RNA, proteins and the neurosecretory material in the supraoptic nucleus, showed the synthesis and depletion of the hormone content in correlation with the plasma concentration of ADH.

Animals↗