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Biomedical subjects

A Bes

Publications and source records attributed to A Bes.

At least 37 records · Page 2Linked to original sources
PubMed1985

Epinephrine, norepinephrine, and dopamine during a 4-day head-down bed rest.

Head-down bed rest at an angle of 6 degrees was used as an experimental model to simulate the hemodynamic effects of microgravity, i.e., the shift of fluids from the lower to the upper part of the body. The sympathoadrenal activity during acute (from 0.5 to 10 h) and prolonged (4 days) head-down bed rest was assessed in eight healthy men (24 +/- 1 yr) by measuring epinephrine (E), norepinephrine (NE), dopamine (DA), and methoxylated metabolite levels in their plasma and urine. Catecholamine (CA) and methoxyamine levels were essentially unaltered at any time of bed rest. Maximal changes in plasma were on the second day (D2): NE, 547 +/- 84 vs. 384 +/- 55 pg/ml; DA, 192 +/- 32 vs. 141 +/- 16 pg/ml; NS. After 24 h of bed rest, heart rate decreased from 71 +/- 1 to 63 +/- 3/min (P less than 0.01). Daily dynamic leg exercise [50% maximum O2 uptake (VO2 max)] used as a countermeasure did not alter the pattern of plasma CA during bed rest but resulted in a higher urinary NE excretion during postexercise recovery (+45% on D2; P less than 0.05). The data indicate no evident relationship between sympathoadrenal function and stimulation of cardiopulmonary receptors or neuroendocrine changes induced by central hypervolemia during head-down bed rest.

Adult↗
PubMed1983

[Antimitotic chemotherapy of supratentorial cerebral glioma in adults. Apropos of 56 cases].

Fifty-six patients with supratentorial gliomas were given chemotherapy (VM 26 and CCNU). Results were analyzed and compared to recent data from the medical literature. After the first great expectations the place of chemotherapy in the management of primary gliomas has now been more accurately delineated: it is an adjunctive therapy, complementary to surgery and radiotherapy. The contribution of chemotherapy, although slight, is unquestionable: in 2/3 of cases a significant improvement of the length of survival can be expected.

Adult↗
PubMed1982

[Blood biorheology and ischemic cerebrovascular accidents].

Blood hyperviscosity is usually observed in ischemic stroke. Our purpose was to study relations between viscosity and the different parameters of blood that influence viscosity, and to search abnormalities of circadian rhythms. 18 stroke patients (8 females and 10 males mean 65.4 years) and 12 normal subjects (4 females and 8 males, mean 68 years) were studied. The measures were realised within the 48 hours after stroke at 6 p.m. and 12 p.m. and the fourth day at 6 p.m. and 12 p.m., by means of a Taylor-Couette type rheometer. Stroke patients have a significant increase of their blood viscosity, but without elevation of blood hematocrit or fibrinogen within 48 hours. Stroke patients have no nocturnal decrease of viscosity, and they don't present the normal circadian periodicity. Perhaps would this phenomenon explain the diurnal variations in occurrence of strokes?

Adult↗
PubMed1982

Hydroelectrolytic and hormonal modifications related to prolonged bedrest in antiorthostatic position.

The effects of prolonged bedrest in antiorthostatic position (-4 degrees head down) on electrolyte balance were studied in 4 young volunteers. An increase was noted in sodium excretion during the first 4 days. Plasma renin activity and plasma aldosterone varied in parallel manner during the same period. Potassium balance and creatinine clearance were not significantly modified. In light of these data we feel that prolonged bedrest in antiorthostatic position constitutes an effective way to simulate on earth metabolic and hormonal modifications occurring in man under weightlessness conditions.

Adult↗
PubMed1982

Changes in the loco-regional Cerebral Blood Flow (r.C.B.F.) during a simulation of weightlessness.

Experiments of prolonged bedrest in antiorthostatic position are conducted in order to simulated cardio-circulatory modifications observed in weightlessness. Until now, no studies of r.C.B.F. have been effected in these conditions. Six young, healthy volunteers (average age 23.8) were placed in strict bedrest and in antiorthostatic position -4 degrees for 7 days. The r.C.B.F. measurements were studied by 133Xe inhalation method using a 32 detectors system. Studies were made first in basal conditions, then between the 6th and 12th hr, and finally between the 72nd and the 78th hr after the beginning of the experiment. Three of the subjects received 0.450 mg of Clonidine daily during the experiment. In the subjects having taken no Clonidine, we observed a constant increase in r.C.B.F. (12, 17 and 16% respectively) in the first 12 hr; at the 72nd hour, all values had returned to basal state. This findings agrees with the well known notion of a rapid correction of hemodynamic disturbances observed in the first days of weightlessness. In the subjects treated with Clonidine, the increase of r.C.B.F. did not occur. Several mechanisms of action are possible; the Clonidine affecting either the heart by inhibiting volemic atrial receptors or the brain by direct vasoconstriction.

Adrenergic alpha-Agonists↗
PubMed1982

[The role of paradoxical sleep in learning in man].

The authors have tried to specify the role of paradoxical sleep (PS) in the learning process in man. For their study they used 12 medical students. Three polygraphic recordings of sleep were performed over 3 consecutive days. The night of the third day was preceded by the learning test (a series of 4 tests). A simultaneous study was carried out of the effects of learning on sleep and vice versa. This study does not show any significant increase in the total time of paradoxical sleep during the night which followed the learning. Only the second period of PS was increased. Thus, this research does not seem to confirm the results obtained in animals. But this disagreement may be explained by the limited number of subjects or by the contents of the tests used. On the other hand, the authors did obtain results which seem to confirm the favourable influence of sleep as a whole on the learning process.

Adolescent↗
PubMed1981

[Bacterial endocarditis on mitral prolapse revealed by cutaneous and neurological disorders. Usefulness of immunological investigations (author's transl)].

In a 32-year-old woman with mitral prolapse, bacterial endocarditis was preceded by a long period of neuralgias and skin lesions. Thrombosis of the Sylvian artery heralded the onset of the disease which remained for a long time apyretic and was marked by several cerebral vascular accidents. After failure of antibiotic therapy the mitral valve was replaced by a Starr valve and the patient recovered. In view of the presence of immunological abnormalities in this patient, the mechanisms of the vascular lesions is discussed. Many authors are new giving a large place to "immunoallergic" theories in their attempts to explain the occurrence of non-specific arteritis in bacterial endocarditis.

Adult↗
PubMed1978

Hemodynamic and metabolic factors in human cerebral ischemia.

Hemodynamic and metabolic cerebral measurements (CBF, CMRO2, CMRG, CSF) were evaluated in stroke patients. To investigate the effects of chronic cerebral circulatory insufficiency, CBF and CMRO2 were also studied. Further nontraumatic investigations of CBF measurement will allow a better understanding of clinical cases.

Acidosis↗
PubMed1977

[Benign intracranial hypertension due to thrombosis of a transverse sinus. Diagnosis by scintigraphy using bleomycin labelled with cobalt 57 (author's transl)].

In a case of benign intracranial hypertension with no apparent aetiology, cerebral scintigraphy demonstrated abnormal uptake in the left transverse sinus 24 hours after injection of the isotope. This sinus was seen to be thrombosed by cerebral angiography. On the basis of this case, the role of cerebral venous thrombosis in cases of "pseudo-tumor cerebri" is discussed.

Adult↗