Biomedical subjects
Publications and source records attributed to P Groza.
Risk factors in patients with ulcer disease have been investigated on a random sample of 214 in-patients admitted during 1985 to two clinical departments. For data collecting, an original questionnaire was developed and submitted. Results were obtained by computer processing. The method permitted quantification of the prevalence of risk factors in peptic ulcer in Romania and also of the relations between them.
Wistar rats (110-125 g) were irradiated with a single dose of 500 R. Histochemical studies were done concerning the glycoproteins (GP) of sublingual glands, gastric, small intestine and colon mucosa, and some intestinal enzymes: acid and alkaline phosphatase (ACP, ALP) leucineaminopeptidase (LAP), Mg-dependent ATP-ase, NADH-diaphorase, lactic dehydrogenase (LDH). After irradiation all these reactions were diminished, with a maximal effect between 3-5 days. This impairment is in accord with the maximal lethality in this interval after such a degree of irradiation that produced the gastrointestinal syndrome. Cocarboxylase, a radioprotector, improved these changes regarding the structures of the small intestine and also the GP of sublingual glands, stomach, small intestine and colon, demonstrating there its efficiency.
From the histochemical investigation carried out on the digestive tract of rats after 7 days space flight in the soviet biosatellite Cosmos 1667 it resulted that neutral and acid glycoproteins diminished slightly in the sublingual gland, stomach, small intestine and the colon. Some intestinal enzymes augmented (leucineaminopeptidase, acid phosphatase, adenosinetriphosphatase and glucose-6-phosphatase). The changes observed after this flight were less marked than after an 18 day flight (in the Soviet biosatellite Cosmos 936 and 1129) and similar to those revealed after 7 days of hypokinesia. The glycoprotein changes were close to those observed after a 5-day flight (Cosmos 1514) but in which there were pregnant rats; after these last flights, the enzymes were not studied.
Coagulation and fibrinolysis were studied in rats exposed to hypokinesia (HK) obtained by including rats (for 1, 2 and 3 weeks) in small cages designed to limit their movements, permitting only spontaneous feeding (a method widely used for mimicking space flight conditions). The number of thrombocytes, the Quick time, the Howell time and the euglobulinlysis time (ELT) decreased after 1 and 2 weeks of HK; however, after 3 weeks, the parameters of coagulation approached normal control levels, while ELT was still significantly under the control values. An increased blood level of corticosterone in animals subjected to HK suggested that changes observed in the blood coagulation could be linked with it. After exposing rats to heat, similar changes were noticed, i.e. thrombocytopenia and an increase in the speed of coagulation and fibrinolysis. When hyperthermia was induced in hypokinetic animals (after 1 and 2 weeks of HK), the association of exposure to HLK and heat was not followed by a cumulative response.
Among the pressor homeostatic mechanisms that appear after hemorrhage are renin-angiotensin response and aldosterone hypersecretion. Plasma renin activity (PRA) may decrease initially but increase always after a certain interval. Aldosterone secretion increases or decreases in a higher or lower degree. It is generally accepted that Ang II is one of the principal factors that stimulates aldosterone secretion, but from our material it resulted that after hemorrhage it evolves independently. This discrepancy is more evident if hemorrhage is followed by bilateral nephrectomy (BN), when PRA significantly decreases but aldosterone secretion increases. After a simple BN, PRA decreases significantly but aldosterone plasma concentration increases, a discrepancy that is more evident if BN are followed by hemorrhage. Thus, it appears that after hemorrhage, the aldosterone secretion is not stimulated by the renin-angiotensin system.
Our previous studies dealt with the dynamics of the fluid-coagulant equilibrium in rats after confinement hypokinesia (CHK) for 1, 2 and 3 weeks obtained by placing them in small cages permitting only slight movements for spontaneous feeding. We found an acceleration of blood coagulation and fibrinolysis, with a maximal response after 1-2 weeks. In this work attention focussed on the initial more dynamic interval of 1, 3 and 7 days of exposure to CHK. To find certain relations between the central vegetative stimuli and the peripheral responses, experiments were done on normal and adrenalectomized rats and plasma corticosterone, the main glucocorticoid in these species, was measured. CHK accelerated the Quick and the Howell time (QT and HT) and euglobulin lysis time (ELT) progressively, beginning with the first day of exposure. Adrenalectomy as such shortened these parameters, demonstrating an inhibitory action of corticoid hormones in normal conditions. Exposure to CHK of adrenalectomised rats emphasizes these inhibitions. We did not found evident correlations between plasma corticosterone and these processes. The number of thrombocytes had a similar evolution, but in adrenalectomised and CHK rats they increase.
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The authors of this article studied the influence of hypoxia, on thirteen groups of male rats, at altitudes of 2 200 m; 5 000 m; and 8 000 m assimilated in a barochamber by chronic or acute exposure (from 2 hours to 21 days) upon the parameters of acid-base equilibrium. The data obtained demonstrated the development of gaseous alkalosis, which is directly proportional to the altitude and time of exposure, hypocapnia, a decrease in excess base and actual bicarbonate, as well as decreased in oxygen pressure. Adrenalin and noradrenalin administered intraperitoneally produced an acidotic effect. Adrenalectomized animals exposed to hypoxia developed mixed alkalosis-respiratory and metabolic reaction.
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White male Wistar rats exposed a single time for 120 minutes to the action of an electric field of 100 kV/m and 50 Hz present a very important increase of the plasma concentration of antidiuretic hormone (ADH). In the case of a 360-minute exposure a 30 per cent reduction of the diuresis as compared with the control takes concomitantly place.
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