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Biomedical subjects

M Vincent

Publications and source records attributed to M Vincent.

At least 361 records · Page 20Linked to original sources
PubMed1980

[Primary postural hypotension. Physiopathological study of 8 cases (author's transl)].

Physiological tests showed that both branches of the baroreflex arc-vagal cardiomoderator and, predominantly, sympathetic vasoconstrictor--were affected. There was no rise in serum and urinary noradrenaline levels in standing position, and adrenaline concentrations were rarely increased under induced hypoglycaemia. Dopamine beta-hydroxylase activity and reactivity of the renin-angiotensin-aldosterone system remained normal in most cases. Physiopathologically, the two clinical forms described (i.e. with and without central nervous symptoms) cannot be differentiated.

Aged↗
PubMed1980

[Effects of labetalol, a new alpha- and beta-adrenoreceptor blocking drug, on arterial pressure, renal function and renin activity (author's transl)].

Labetalol, a blocker of alpha- and beta-adrenoreceptors, was tried on 45 patients with severe (29 cases) or mild to moderate (16 cases) hypertension. After an initial period of dosage adjustment and a 2 months treatment in effective doses, there was a significant fall in supine blood pressure from mean values of 207/132 to 170/106 mmHg. In 23 patients hypertension was controlled by labetalol alone in doses of 400 and 1800 mg per day. True failures were rare (16%). Digestive disorders and postural hypotension were the most frequently encountered side-effects; they obliged to discontinue treatment in 4 cases, but were compatible with it in 11 cases. In 22 patients the fall in BP was accompanied by a significant (p less than 0,001) decrease in plasma renin activity from 123 to 44 ng/l/min supine and from 144 to 83 ng/l/min standing. Studies of the renal function showed no changes during oral therapy. Following intravenous injection of 50 mg labetalol to 20 subjects, inulin and PAH clearances remained unaltered, and there was a significant, though transient (1 hour), decrease in chloride, sodium and phosphorus excretion. Effective in lowering blood pressure be used and well tolerated by the kidneys, labetalol can safely be used for the treatment of severe hypertension with organic renal involvement.

Adolescent↗
PubMed1980

Plasma renin activity, aldosterone and dopamine beta-hydroxylase activity as a function of age in normal children.

In 149 children between 6 days and 15 years of age, plasma renin activity (PRA) and aldosterone (PA) were measured by radioimmunoassay and plasma dopamine beta hydroxylase activity (DBH) by the method of Nagatsu. PRA and PA decreased with age from 496 +/- 119 ng/1/min for PRA and 643 +/- 158 pg/ml for PA in 6 to 30 day-old newborns to 37.8 +/- 4.7 ng/1/min for PRA and 43. 1+/- 8.3 ph/ml for PA in 9 to 15 year-old children. DBH increased with age from less than detection limit values (< 2 IU) in 6 day to 3 month-old newborns to 17.2 +/- 5.1 IU in 9 to 15 year-old children. In addition a significant relationship was found between PRA and PA (log PA = 0.99 log PRA -0.058, r = 0.732, n = 104, p < 0.001) and PRA and DBH (log DBH = -0.41 log PRA +1.62, r = 0.404, n = 80, p < 0.001). These results demonstrate the opposite evolution of the Renin-Angiotensin-Aldosterone System and of the sympathoadrenal system during development.

Adolescent↗
PubMed1980

Urinary excretion of catecholamines and metabolites in the Lyon strain of genetic hypertensive rats.

Urinary catecholamines (Norepinephrine : NE, Epinephrine : E) methoxylated amines (Metanephrine : MN, Normetanephrine : NMN) and 3-methoxy-4-hydroxyphenylglycol (MHPG) have been studied in the Lyon hypertensive strain of rats (LHS) and their normotensive controls (LNS) at three ages (5, 9 and 21 weeks) characteristic of the development of hypertension. In 5-week-old rats, increased excretion of E, MN, NMN and early elevation of the ratio E/E+NE were observed, thus suggesting a sympatho-adrenal hyperactivity, with accelerated maturation of E secretion. At adult age, the excretion of most adrenergic metabolites was similar in the two strains of rats. However, the data from adult LHS are difficult to interpret because of a potential renal impairment at this age. Furthermore, there was a positive correlation between systolic blood pressure and urinary catecholamines at 5 weeks and 9 weeks of age but not at 21 weeks. It is suggested that the early sympathoadrenal hyperactivity, which disappears with age, may be related to the onset of hypertension in the Lyon strain of hypertensive rats.

Adrenal Glands↗
PubMed1980

[Renin-angiotensin system. Physiological importance. Methods and study in humans (author's transl)].

After a brief review of the biochemistry of the renin-angiotensin system (R. A. S.) components and of their pharmacological inhibitors, the authors describe the main biological effects of angiotensins. A particular emphasis is given to the synergistic effects of the sympathetic nervous system and of the R. A. S., and their major influence on the regulation of hydromineral metabolism and blood pressure. The methods developed for the study of R. A. S. are critically described. Finally, the most important clinical indications of the study of R. A. S. activity are given, and a special attention is paid to the conditions in which such a study must be developed in humans.

Adolescent↗
PubMed1980

[Regulation of genetic expression during the transfer of information from the nucleus to the cytoplasm].

In eukaryotes, the transfer of genetic information from the genome to its final site of phenotypic expression is a multistep process. These steps are described and the mechanisms of regulation operating at these various levels are reviewed. The heat shock response in two diptera, Drosophila and Chironomus, is described as a model system to illustrate the existence of regulation mechanisms at different levels of genetic information transfer. In Chironomus tentans like in Drosophila, a short heat shock (10 min, 39 degrees C) treatment induces the synthesis of at least 8 new proteins. This is accompanied by a drastic reduction in the synthesis of the normal proteins that in those synthesized prior to the shock. The localisation of these induced proteins has been studied by microdissection of the various intranuclear and intracellular compartments of salivary glands. While most of these have a ubiquitous distribution, one induced protein (34 000 Daltons) is exclusively localized in the nucleus. Another one (25 000 Daltons) is mainly concentrated in a particulate form which cosediments with ribosomes. Arsenite and anaerobiosis do not induce a heat shock mimicking response in Chironomus. The induction mechanisms as well as the transcriptional and translational controls operating during the heat shock response are discussed.

Animals↗
PubMed1980

[The Lyonnese strains of genetically hypertensive, normotensive, and hypotensive rats].

The 3 lyonnese strains of genetically hypertensive (LH), normotensive (LN) and hypotensive (LL) rats were simultaneously selected by inbreeding from one group of Sprague-Dawley rats. The breeders were chosen on the basis of two parameters: the mean of the systolic blood pressures measured between six to twelve weeks of age and the slope of the systolic blood pressure increase with age. The LH strain exhibited a mild hypertension which progressively developed during the selection and was associated with an enlarged body weight and a spontaneous increase of plasma lipids. The simultaneous selected LN strain was found to provide valuable control animals. The LL rats, which were very difficult to select, would appear useful to stress, among the differences found between LH and LN rats, those which could be linked to the blood pressure alterations.

Animals↗
PubMed1980

[Development of early kidney lesions in genetically hypertensive, normotensive and hypotensive rats].

Morphological changes were studied in 3 different strains of rats genetically hypertensive (LH) normotensive (LN), or with low blood pressure (LL). Renal lesions were evaluated at 3, 5, 9, and 21 weeks of age, when blood pressure was significantly different between the 3 groups and the difference increased up to 21 weeks of age. Small histological changes could be detected in the LH groups as early as the fifth week (2 cases out of 8). However the differences between hypertensive rats and normo or hypotensive rats were obvious only at 9 weeks progressively increasing up to the 21th week. The juxta glomerular apparatus was mainly affected with hypertrophy and hyalinisation and hyaline deposits within the wall of the afferent arteriole and lacis cells. The lesions were constant although focal and of moderate intensity. They were frequently associated with segmental hyalinisation of the glomerulus and slight tubular and interstitial changes. The comparative study between three strains of rats shows that the renal vascular lesions appear early but after the onset of hypertension.

Aging↗
PubMed1979

Heat-shock induced proteins present in the cell nucleus of Chironomus tentans salivary gland.

The heat shock (HS) system has been largely studied in Drosophila but the molecular mechanisms responsible for the induction of the heat shock genes as well as the function(s) and the intracellular localisation of the induced proteins is still unknown. It has previously been shown that the HS puff induction is accompanied by a local increase of nuclear nonhistone proteins (NHP) but the nature of most of the proteins accumulating is unknown. We have investigated the effects of a heat shock on Chironomus tentans salivary glands, a system where it is possible to study constituents in various subcellular or intranuclear regions including individual puffs, by microdissection. We report here evidence that at least two of the polypeptides synthesised in response to the heat shock migrate to the nucleus. Furthermore, these two proteins appear to have a broad intranuclear distribution, as shown by their presence in the various microdissected nuclear fractions.

Animals↗
PubMed1979

Dihydralazine and catecholamine-synthesizing enzymes in spontaneous hypertension.

Dihydralazine treatment which lowered blood pressure in young rats from the Lyon Hypertensive Strain (LHS), did not change phenylethanolamine-N-methyltransferase (PNMT) activity, but decreased tyrosine hydroxylase and dopamine-beta-hydroxylase activities in the C2 medullary region. These data suggest that the increase in PNMT activity, previously described for this strain, is not a consequence of the developing hypertension and that hypotensive treatment could inactivate some catecholaminergic neurons of the medulla oblongata.

Adrenal Medulla↗
PubMed1979

Ouabain-sensitive and -insensitive ATPase activities in the kidney and the liver of spontaneously hypertensive rats.

Ouabain-sensitive and-insensitive ATPase activities were measured in the kidneys and the kidneys and the liver of male and female rats of the Lyon hypertensive (LHS) and Lyon normotensive strain (LNS). At the age of 48 +/- 2 weeks, hypertensive rats exhibited a significantly higher blood pressure and body weight than age-matched normotensive rats. Ouabian-insensitive ATPase activity was decreased in the kidney, but not in the liver of hypertensive rats compared to normotensive rats. Ouabian-sensitive ATPase activity was non significantly decreased in the kidney of hypertensive rats.

Adenosine Triphosphatases↗
PubMed1979

Successful indomethacin treatment of two paediatric patients with severe tubulopathies. A boy with an unusual hypercalciuria and a girl with cystinosis.

Two children were followed for severe congenital tubulopathies: a boy presented an excessive sodium, calcium and water excretion; a girl had cystinosis and a De Toni-Debré-Fanconi syndrome. These renal defects were both associated with increased levels of plasma renin activity and aldosterone, and excessive urinary PGE1 production. They had been unresponsive to therapeutic attempts. Only indomethacin treatment was successful in reversing the biochemical abnormalities and improving the growth pattern.

Aldosterone↗