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Biomedical subjects

J Sassard

Publications and source records attributed to J Sassard.

At least 199 records · Page 11Linked to original sources
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

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

[Hypertension due to unilateral parenchymatous nephropathy (author's transl)].

One hundred and eight patients suffering from hypertension due to a unilateral parenchymatous neophropathy were studied over a period of one to eight years after treatment was starded. The aetiologies were diverse: harmonious hypoplasia, segmental hypoplasia, pyelonephritis, reflux nephropathy, hydronephrosis and tuberculosis. Thirty nine patients were treated surgically, with 50% good results. In 82 cases medical treatment was continued for at least a year with a 52% success rate. Such success was recorded in 94% of cases in which beta-blockers were used (38 cases). Surgical success was not dependent upon the period for which hypertension had been present. The best results were seen in cases of hydronephrosis and pyelonephritis and the worst in tuberculosis. Thirteen patients underwent surgery event though there was no unilateral increase in plasma renin levels. Seven were improved or cured. Ten patients underwent surgery with a renin activity 50% greater than on the healthy side, 9 being improved or cured. Treatment with beta-blockers, alone or in association with diuretics, controlled blood pressure in 90% of cases, regardless of the renin activity. Plasma renin activity in the renal veins is of good prognostic value in terms of the effectiveness of nephrectomy against hypertension. In Call cases, beta-blockers were more effective than surgery.

Adrenergic beta-Antagonists↗
PubMed1979

Pharmacokinetics and bioavailability of pyridinol carbamate in humans.

The pharmacokinetics of two pyridinol carbamate formulations were studied after a single oral administration in 10 healthy volunteers. An open one-compartment model described the evolution of plasma concentrations as a function of time. Pyridinol carbamate was rapidly absorbed (mean lag time from 0.36 to 0.38 hr). Its elimination half-life ranged from 3.3 to 7.9 hr. The two formulations were bioequivalent.

Adult↗
PubMed1979

Pharmacokinetics of fenbufen in man.

The pharmacokinetics of fenbufen (3,4-biphenylcarbonyl proprionic acid) a new antiinflammatory agent, and its metabolites, gamma-hydroxy-4-biphenylbutyric acid and 4-biphenylacetic acid have been studied after oral administration to seven patients with rheumatoid arthritis. Fenbufen was administered as a single oral dose of 600 mg in hard gelatine capsules. A specific, sensitive gas chromatographic method was used to measure the concentration of the three compounds. A linear two-compartment open model appeared suitable to describe the course of the plasma level of fenbufen with time. This compound appeared in the blood after a lag time of 0.45 h and the peak plasma concentration of 5.97 micrograms/ml was observed after 1.19 h. The half-life of plasma disappearance was 10.26 h for fenbufen and 10.07 h and at 9.95 for metabolites II and III, respectively.

Adult↗
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↗
PubMed1978

Early increase in phenylethanolamine-N-methyltransferase activity in a new strain of spontaneously hypertensive rats.

By repeated inbreeding, 2 strains of spontaneously hypertensive and normotensive rats have been simultaneously selected. The activities of tyrosine hydroxylase and phenylethanolamine-N-methyltransferase were determined in various central catecholaminergic nuclei (C1, C2, A6 and A9) and in two peripheral tissues (adrenal glands and superior cervical ganglion). These assays were performed on rats belonging to the normotensive or the hypertensive strain at 3 ages which characterize the development of hypertension (5, 9 and 21 weeks). Except for a decrease in the C1 region of 9-week-old rats, no significant change in tyrosine hydroxylase activity occurred in central or peripheral structures of the spontaneously hypertensive rats when compared to the normotensive rats. In contrast, the activity of the phenylethanolamine-N-methyltransferase (PNMT), was increased in the C2 adrenergic group of the medulla oblongata in young spontaneously hypertensive rats: +43% (P less than 0.001) at 5 weeks of age and +32% (P less than 0.001) in 9-week-old rats. However, there was no significant difference between the 21-week-old rats. No modification of the PNMT activity was found in the C1 adrenergic group of the medulla oblongata. PNMT activity was increased significantly in the adrenal glands of 5-week-old hypertensive rats (+22%, P less than 0.001). By 9 weeks, the difference in PNMT activity in the adrenals was no longer significant. Thus, in young rats of the hypertensive strain, there was an increase in the capacity to synthetize adrenaline in the C2 area of the medulla oblongata and in the adrenal glands. While the enzymatic change present in the adrenals seems to be specific to this new strain of hypertensive rats, the elevation of PNMT activity in a specific region of the medulla oblongata (C2 group) is a characteristic common to at least two independently derived strains of genetically hypertensive rats.

Adrenal Glands↗
PubMed1978

Influence of renal nerves on renin secretion in the conscious dog.

In order to evaluate the influence of renal nerves on renin secretion during changes in blood volume, we studied the mean arterial blood pressure (MAP) and the renal venous plasma renin activity (PRA) in 6 conscious dogs having one intact and one denervated kidney. After a passive head-up tilt PRA increased significantly in the vein of the intact kidney while it remained stable in the denervated one. The intravenous injection of Furosemide (3 mg/kg) induced a rapid elevation of PRA in both renal veins. The kinetics of the variations of renin secretion were similar in the two kidneys, but its magnitude was significantly lower in the denervated side. After a slow hemorrhage of 2, 4 and 6 ml/kg, MAP was unchanged and PRA increased in both renal veins but in a significantly lower degree in the denervated side. When blood loss reached 8 ml/kg, MAP decreased and PRA increased identically in the two renal veins. It was concluded that, in conscious dogs, the renal nerves could participate in the rapid adaptations of renin secretion during small changes in the circulating blood volume.

Animals↗
PubMed1978

Thyroid function and blood pressure in two new strains of spontaneously hypertensive and normotensive rats.

1. The influence of thryoid function on the development of hypertension was studied in strains of spontaneously hypertensive (SH) and normotensive rats. 2. Surgical thyroidectomy decreased systolic blood pressure more markedly in SH rats than in normotensive rats. The effects of oral administration of 5 and 100 micrograms of thyroxine 24 h-1 100 g-1 were studied in the thyroidectomized animals. In the two strains the blood pressure returned to control levels only after administration of the larger dose. 3. The evolution of body weight, total plasma tri-iodothyronine (T3) and tetraiodothyronine (T4) concentrations were followed as a function of age in SH rats and normotensive rats from 5 to 21 weeks. At each age, SH rats showed significantly larger body weight and decreased T4 concentrations. Plasma T3 in SH rats was lower than in normotensive rats until 15 weeks of age, after which the difference was not significant. At 11 weeks, plasms free T3 and T4 concentrations were slightly lower in SH rats than in normotensive rats. 4. The more marked hypotensive effects of surgical thyroidectomy in SH rats cannot be related to increased thyroid function.

Aging↗
PubMed1978

Correlation between evolution and treatment of hypertension in unilateral renal disease and values of renin activity in renal venous blood.

93 patients with renal hypertension and renal vein PRA determination were studied during 1--5 years follow-up. They were separated in two groups of medical and surgical treatment. Medical treatment is able to normalize blood pressure even in cases with high asymmetric PRA. 9 of 16 patients could be cured or improved in the surgical group and 14 of 22 in the medical group. The best results were obtained if beta-blockers were included in the drug regimen: cured or improved were 7 of 33 patients in medical treatment without beta-blockers, 17 of 28 in surgical treatment, and 31 of 32 in medical treatment including beta-blockers with or without hydralazine and/or diuretics.

Adolescent↗
PubMed1978

Maternal and fetal plasma renin and dopamine-beta-hydroxylase activities in toxemic pregnancy.

Toxemic and normotensive pregnant women were compared for plasma renin activity (PRA), aldosterone (PA), and dopamine-beta-hydroxylase (DBH). At term, hypertensive patients exhibited higher levels of PRA and PA, but similar levels of DBH, progesterone, and estradiol. Their elevated blood pressure was significantly correlated to their levels of PRA. During the delivery levels of PRA increased significantly in toxemic patients in spontaneous labor. Venous and arterial cord PRA levels were higher in babies born to hypertensive mothers than in babies born to normotensive mothers. Three days postpartum, maternal PRA level was lower than at term. Seven days postpartum, PRA levels remained higher in toxemic than in normal women. Maternal DBH levels did not change during and after delivery. Levels of DBH were undetectable in cord blood. We conclude that the renin-angiotensin system is involved in the pathogenesis of toxemia.

Adult↗