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Biomedical subjects

P Groza

Publications and source records attributed to P Groza.

144 records · Page 8Linked to original sources
PubMedDate not supplied

The digestive tract after 7 days of restraining conditions in normal and adrenalectomized rats.

Hypokinesia produced specific reactions in tissues related to motion (bones, skeletal muscles and myocardium) and nonspecific in others, as that of the digestive tract after 7 days of hypokinesia. A decreased content of glycoproteins from mucous salivary glands, stomach, small intestine and colon, and an increased intestinal content of leucine-aminopeptidase and acid and alkaline phosphatase were found as a result of histochemical reactions. An important plasmatic corticosterone increase was also found. The same histochemical modifications appeared in adrenalectomized rats in which the plasma corticosterone was substantially diminished. Therefore these glycoproteins and enzymatic secretions are not dependent on the glucocorticoid response.

Adrenalectomy↗
PubMedDate not supplied

Digestive tract of rats after hypokinesia and hypergravitation.

We found in rats submitted to a 7 days interval of hypokinesia a decreased glycoprotein content in salivary mucous glands, gastric and intestinal mucosa, an increased glycoprotein content and an increased content of leucine-aminopeptidase, acid and alkaline phosphatase. Similar changes were found after a short interval of centrifugation (+6 Gz, 10 min). These nonspecific responses were more accentuated if the hypergravitation was performed after 7 days of hypokinesia. We reproduced this way this events that occurred in space flight and deacceleration before landing.

Acceleration↗
PubMedDate not supplied

The influence of magnetic fields on some humoral parameters and on resistance to hyperthermia in rats.

The influence of magnetic fields of moderate intensities (50 and 120 Oe) was studied in rats after single or repeated exposures with or without a rise in environmental temperature. The following parameters were investigated: the number of erythrocytes and leucocytes, the percentage of different varieties of leucocytes, serum Na+ and K+, plasma corticosterone, ascorbic acid in adrenals, blood catecholamines, plasma fibrinolytic activity, plasma antidiuretic hormone. The resistance to hyperthermia was tested after single exposures to magnetic fields and the survival time was measured. The only significant change recorded in the number of blood cells was a leucopenia after single exposures to 50 Oe for 4 hrs. The parameters indicating the activity of the adrenal cortex were not altered significantly. A moderate rise in blood noradrenaline suggested a possible mild stimulation of the adrenergic system. The plasma fibrinolytic activity was significantly stimulated after single exposures, but no change in fibrinolysis could be recorded after repeated exposures to magnetic fields. Changes observed in plasma ADH were not conclusive. The resistance of animals to hyperthermia - as a general test of reactivity - showed minimal changes in the survival time, loss of weight, and rectal temperature in animals exposed to hyperthermia (40 degrees C) under the influence of the magnetic fields.

Animals↗
PubMedDate not supplied

Modified gravitational field and lactate dehydrogenase activity.

The paper deals with the effects of the gravitational field investigated either by hypokinesia with corresponding diminution of muscle solicitation, or by centrifugation, that is by rise of gravitational solicitation, on lactate dehydrogenase activity of rats. After 7 days of hypokinesia the activity of lactate dehydrogenase is significantly changed by the elevation of LDH5 isoenzyme, both in serum and in myocardium. The enhancement is by 40% in serum and by 30% in myocardium against the control group. In centrifuged rats the enhancement of LDH5 isozyme is much lesser than in hypokinetic rats, that is by 18% in myocardium and by 20% in serum against the control group. The total of all LDH1-5 isozymes was found in cardiac muscle of both hypokinetic, centrifuged and control group. In serum only two fractions LDH2 and LDH5 isozymes appear both in hypokinetic, centrifuged and control group.

Adrenalectomy↗
PubMedDate not supplied

Hydroelectrolytic changes caused by prolonged clinical recumbency.

Investigations effected in 16 subjects of 20-69 years at bed rest after bone fractures demonstrated, in an interval of 10-27 days after surgery, normal plasma sodium concentration and a decreased urinary elimination, an increased plasma potassium concentration but a decreased urinary output. The osmotic changes were not significant. The plasma vasopressin activity was increased. Three urinary aldosterone determinations showed an increased output. The serum calcium level was within normal limits but its urinary output was initially slightly decreased, contrary to its augmented elimination after simple voluntary bed rest, as results from literature. The hydroxyproline elimination was increased, demonstrating an active collagen metabolism.

Adult↗
PubMedDate not supplied

The role of the sympathoadrenergic reaction in adaptation of the organism to the action of + 6 Gz acceleration.

In experiments on rats the symphathoadrenergic reactivity after a + 6 Gz acceleration was investigated. Hypergravitation produced as a rule a short initial bradycardia, followed by tachycardia. Hexamethonium (C6), a peripheric ganglion-blocking agent, produced bradycardia, diminution or vanishing of the initial bradycardic episode, and a decreased tachycardic reaction. No initial bradycardic response was observed ater atropine. Atropinized and C6-treated rats showed an increased heart frequency response. Centrifugation produced a decreased adrenal catecholamine content and a blood noradrenaline elevation. C6 importantly decreased both catecholamines content in blood. On this background the acceleration produced a slight increase of both blood catecholamines.

Acceleration↗
PubMedDate not supplied

The sympatho-adrenergic response in hyperthermia.

The sympatho-adrenergic reaction was investigated in heated rats under the influence of a ganglioblocking agent--hexamethonium. The overheating at a 40 degrees environmental temperature produced in a relatively short interval (after 157 min on an average) the death of the animals. An initial bradycardia was followed by a tachycardic phase. In the prelethal phase there appeared bradyarrhythmia produced by conductibility troubles and activation of ectopic ventricular centers. The survival time was not influenced by hexamethonium in spite of its hypothermic action. In blood, heating produced an increased concentration of noradrenaline and adrenaline. Hexamethonium, which reduced the rectal temperature, markedly decreased both blood catecholamines concentration. On this background heating likewise produced a relative increase of both blood catecholamines content. The catecholamines changes in adrenal glands presented less significant modifications.

Animals↗
PubMedDate not supplied

Blood and urinary catecholamine variations under the action of a high voltage electric field.

White Wistar male rats, weighing 150 +/- 20 g, adapted to the laboratory ambience during 12 days, were exposed to an electric field of 100 kV/m for 360 minutes in acute (once) or chronic experiment (12 days running). Urinary (nanogram h-1) and blood catecholamines (microgram/100 ml) showed a significant increase as compared to the controls, adapted to the ambience but not exposed to an electric field. The most accentuated increase was that of adrenaline in the acute experiment. In the chronic experiment the adrenaline response gradually failled.

Animals↗
PubMedDate not supplied

The effect of a high-voltage electric fiedl on neurosecretion and on certain diencephalic protein fractions in the rat.

Exposure of Wistar male rats to an electric field of 100 lV/m for 120 minutes produced intense mobilization of the neurosecretory material in the supraoptic and paraventricular nuclei and significant changes in some protein fractions of the hypothalamus, pineal body and neurohypophysis. The significance and possible mechanisms of these effects are discussed.

Animals↗