PubMed Health⌕ Search

Biomedical subjects

S Cananău

Publications and source records attributed to S Cananău.

15 recordsLinked to original sources
PubMed1975

Hypergravitation and sympatho-adrenergic reactivity.

The cardiac frequency and adrenal and urinary catecholamine content were investigated on 10-minutes centrifuged rats (+6 Gz). It was found that the heart responds in an individual manner, with a general tendency to tachycardia. Under the same conditions after 1 1/2 minute the adrenal noradrenaline response was absent, after 3' and 6' the adrenal noradrenaline content was augmented and the adrenaline one diminished, and after 10' the response vanished. Hypergravitation does not change the urinary noradrenaline elimination collected after 10 minutes of centrifugation, but that of adrenaline is augmented in one of the two explored animal groups. The difference between the two groups may be explained by the great individual variations, as results from the cardial frequency (appreciated by teleelectrocardiogram). The environmental stress produces similar but more reduced catecholamine modifications.

Acceleration↗
PubMedDate not supplied

Na+ and K+ dependent ATP-ase and structural modifications in hypokinetic rats.

In rats the hypokinetic state obtained by restraint in special cages, produces after 30 days, a marked decrease in Na+ and K+ dependent ATP-ase in the skeletal muscle. After 15 days hypokinesia the enzymatic content of the investigated tissues did not change. In the left cardiac ventricular muscle Na+ and K+ dependent ATP-ase decreased after 15 days and particularly after 30 days hypokinesia. These changes were brought about by the hypofunctional state of both muscles, which also produced structural alterations. In the skeletal and cardiac muscles electron microscopy revealed fibrillar atrophy and mitochondrial alterations typical of an affected function. In the cardiac muscle, in which these changes were more accentuated, the dissociation of the intercalar disc was also noted, aspects partially described by others.

Adenosine Triphosphatases↗
PubMedDate not supplied

Digestive structural modifications in rats submitted to 15 days of hypokinetical conditions.

Restraining rats for 14 days in special cages in order to determine a hypokinetical state decreased mucopolysaccharide secretion in submaxillary glands and gastric mucosa. In the small intestine and in the colon, concomitantly with an enzymatic (leucine-aminopeptidase and acid phosphatase) hypersecretion as results from specific histochemical reactions. These modifications show maximum intensity at the end of the interval. The corticosterone plasmatic level determined in the same interval also increased, suggesting this way to a causal relation. The histomorphological changes presented delayed reaction. This material is in accord with our previous investigations as well as with some literature data.

Acid Phosphatase↗
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

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↗