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Biomedical subjects

G Rorive

Publications and source records attributed to G Rorive.

At least 73 records · Page 4Linked to original sources
PubMed1990

[Effect of long-term administration of vasodilators and "antitrophic" agents on the structure and function of the heart in hypertensive rats].

In this study, we determined whether the persistency of cardiac hypertrophy after chronic vasodilation therapy with minoxidil (minox) was associated with functional or metabolic alterations in hypertensive rat hearts before, during and after an ischemic insult. In addition, we investigated the effects of the simultaneous administration of difluoromethylornithine (dfmo), a substance that could block hypertrophy by a direct inhibition of protein synthesis. Four groups of male Wistar rats were prepared: 1) normotensive controls (n = 8), 2) untreated renovascular hypertensive rats (HT, n = 15), 3) hypertensives treated with minox (8 mg/kg, n = 19), 4) hypertensives treated with minox and dfmo (1.7 g/kg, n = 20). After 21 days of treatment, the animals were sacrificed. In a small number of hearts, ornithine decarboxylase (ODC) activity was assayed in order to verify that dfmo, which is a suicide inhibitor of ODC, had effectively interrupted the polyamines pathway. The other hearts were prepared for retrograde perfusion at 35 degrees C and at constant flow (10 ml/min x g). Cardiac function was monitored via the balloon inserted in the left ventricle (LV) and the following protocol was applied: a) baseline period (24 min), b) ischemia (24 min), c) recovery (36 min). Finally, the hearts were weighed and LV wall thickness and inner radius were measured. Blood pressure was maintained near normotension in the two treated groups. Mean systolic pressure (in mmHg) was 145 +/- 4 with minox and 144 +/- 3 with minox + dfmo versus 181 +/- 4 in the HT group (p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Arguments for the existence of an endogenous inhibitor of renal Na-K ATPase with steroid structure and natriuretic action].

In order to explain the opposite effect of 6,7-dihydroxylated isomers of 6, 7 - dihydrocanrenone on the urinary sodium and potassium excretion, we have tested the effect of these substances isolated from human urine on the Na(+)-K+ pump from different tissue preparation: rabbit kidney slices as well as NA-K ATPase purified from the kidney. Our results show an inhibition of pump as well as enzyme activity by the 6 beta 7 alpha isomer while the 2 other isomers are either uneffective or slightly stimulating. The 6 beta 7 alpha dihydroxy-6, 7-dihydrocanrenone could be one of the plasma ouabain-like substance incriminated in the pathogenesis of volume-expanded hypertension.

Animals↗
PubMed1990

A double blind comparison of perindopril and atenolol in essential hypertension.

A multicentre randomised double-blind trial was performed in order to compare the therapeutic efficacy and acceptability of the angiotensin converting enzyme (ACE) inhibitor perindopril with those of atenolol in mild to moderate hypertension. After one month of placebo, 173 patients with supine diastolic blood pressure (DBP) between 95 and 125 mmHg were randomised to receive perindopril 4 mg once daily or atenolol 50 mg once daily. Monthly assessments were made for three months. Treatment was adjusted at these visits if supine DBP was greater than 90 mmHg; the dose was first doubled (8 mg perindopril or 100 mg atenolol once daily) and then hydrochlorothiazide was added. The pretreatment blood pressure levels were similar in both groups. Supine DBP was 105.5 +/- 0.9 mmHg (n = 85) in the perindopril group and 106.9 +/- 0.9 mmHg (n = 88) in the atenolol group. At the end of the third month, the study target blood pressure (supine DBP less than or equal to 90 mmHg) was achieved in a significantly (P = 0.006) larger percentage of patients in the perindopril group (78%) than in the atenolol group (58%). This appeared to be due to a greater potentiation of the antihypertensive effect by the addition of diuretic to perindopril than to atenolol. The fall in systolic blood pressure was significantly greater in the perindopril group than in the atenolol group (supine: 26.5 +/- 2.0 mmHg vs. 20.6 +/- 2.0 mmHg; P = 0.042) although the fall in DBP was comparable (supine: perindopril 17.4 +/- 0.9 mmHg, atenolol 15.6 +/- 1.1 mmHg; P = 0.195).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Isradipine in essential hypertension: the Belgian General Practitioners' Study.

Over 200 hypertensive patients were recruited by 37 general practitioners into a single-blind 12-week study to assess the efficacy, tolerability, and safety of isradipine as an antihypertensive, alone and in combination with guanfacine. A total of 212 patients were given isradipine at doses of 1.25 and 2.5 mg twice daily. Twelve hours after the last dose, diastolic blood pressure was reduced to no more than 90 mm Hg in 52.6 percent of patients treated with isradipine alone. After eight weeks of treatment, 30 percent of patients were also given guanfacine 1 mg daily. By Week 12, 67.6 percent of the patients had attained normotension. Compared with placebo, side-effect frequency was higher for flushing and edema with isradipine, and dry mouth was more frequent with added guanfacine. Electrocardiographic examinations and routine laboratory determinations showed no clinically relevant changes. These data indicate that isradipine as monotherapy and in combination with guanfacine is an effective antihypertensive agent. Most patients will continue to participate in a two-year follow-up involving bimonthly clinical visits and half-yearly electrocardiographic examinations and laboratory determinations.

Adrenergic alpha-Agonists↗
PubMed1989

[Does dopamine play a role in renal anomaly in sodium excretion, a marker for hereditary predisposition to arterial hypertension?].

Since Dahl's observation, a renal defect os sodium excretion is proposed as one of pathogenetic mechanism of hypertension (HTA). Our study has tried to verify this concept in 20 young normotensives with (n = 12) and without (n = 8) familial predisposition to HTA, allowing to test the genetic transmission of such potential renal abnormality of sodium balance. Each people was submitted to 3 different Na diet (20, 170 and 340 mM NaCl) each for 1 week. At each visit, blood pressure, vascular resistances, biological values were determined at rest (plasma renin activity, creatinine clearance, 24 hours before the test, catecholamines, aldosterone and ion urinary excretion). Then 1 liter of isotonic saline was perfused in 30 minutes with measures of blood pressure and 3 hours urinary dopamine and Na excretion. During the low and medium Na diets, but not during the high Na diet, the natriuresis and dopamine excretion were lower in the 3 hour urine collection in patients with a family history of HTA (p less than 0.02 and p less than 0.005, respectively). No other clinical or biological difference was noted between the 2 groups. Thus, genetic hypertensive predisposition seems to be characterized by a lower Na excretion during acute Na loading in normal or depleted Na diet, linked to an impaired urinary dopamine excretion. These findings suggest that the defect responsible for the susceptibility to sodium intake is at the kidney level. Some dopamine agonists would be of great therapeutical value in treating such patients when blood pressure begins to rise.

Adult↗
PubMed1989

[Arterial pressure in adolescents: epidemiologic approach].

The epidemiological survey of a sample of Belgium teenagers aged from 12 to 17 provides the reference values of blood pressure and illustrates the importance of weight and mainly of overweight as a determinant of blood pressure in this population. The longitudinal part of the study clearly establishes the importance of the tracking phenomenon and the significance of the casual finding of an elevated blood pressure in a teenager aged from 13 to 17 years.

Adolescent↗
PubMed1988

Double-blind comparison of ketanserin and propranolol in hypertensive patients.

In this double-blind study in general practice, 444 patients were randomized to ketanserin (K, 40 mg b.i.d.) and 229 patients were randomized to propranolol (P, 80 mg b.i.d.). After 3 months, more patients on K (15%) than on P (9%) had been withdrawn (p less than 0.02). Although at 3 months the falls in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were similar in both groups, the reduction in SBP was slower on K, and up to 2 months SBP was higher on K than on P (p less than 0.04 or less). At randomization and after 3 months, average weights were similar in both groups. However, during the first month of the study, patients on K gained weight, and this change in weight differed (p less than 0.02) from the unchanged weight on P. On K, BP lowering was greater when weight gain was less. Multiple regression analysis showed that after adjusting for BP at randomization and subsequent weight changes, DBP at 1 month on K was lower with advancing age, whereas SBP and DBP at 1 and 3 months on P were higher with age. Severe adverse effects were absent. However, dry mouth, edema, fatigue, and dizziness occurred more frequently with K (p less than 0.04 or less).

Adolescent↗
PubMed1988

Cardiovascular risk factors in a sample of a rural Belgian population: the Bellux MONICA Study.

A sample of 1949 subjects of the population of the Belgian province of Luxembourg was screened for levels of cardiovascular risk factors. Cigarette smoking was more prevalent among males (51%) than among females (17%). The relationship between smoking and socio-economic status was inverse in males (M) and direct in females (F). Blood pressure (BP) measurements showed definite high BP in 10% of this sample, and 60% of those with definite high BP were not taking any hypertensive drugs. The average total cholesterol value was 6.49 mmol/L in M and 6.45 mmol/L in F. F had lower values than M at a younger age, but higher values than M at an older age. The high-density lipoprotein cholesterol was higher in F (1.57 mmol/L) than in M (1.27 mmol/L). Diabetes was present in 4.2% of this sample. In nearly half of these participants, the disease had been discovered during the screening. Obesity was especially frequently among F in all three age groups. In conclusion, the main cardiovascular risk factors were found to be at a fairly high level in this population sample.

Adult↗
PubMed1988

Influence of sodium balance on uremic red blood cell ion transport.

This study was performed to test the effect of dialysis-induced acute modifications of plasma volume and sodium pool on red blood cell (RBC) ion transport in patients with end-stage renal disease. This approach confirmed the presence of an Na-K pump inhibitor in the plasma of uremic patients with extracellular fluid volume expansion. This factor cross-reacts with digoxin antibodies, and its concentration decreases during dialysis; this explains the increased activity of the RBC Na-K pump that is consistently observed during dialysis.

Adult↗
PubMed1987

Serum cholesterol during ketanserin and propranolol administration in hypertensive patients.

The effect of ketanserin and propranolol on the serum total cholesterol (TC), and high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) cholesterol was studied in hypertensive patients treated for 3 months. During ketanserin administration, LDL-C decreased, whereas HDL-C and the HDL-C/LDL-C ratio increased and no significant effect in serum total cholesterol occurred. During propranolol administration, no significant effect was observed on serum total cholesterol, HDL-C and LDL-C, but the ratio of HDL-C/LDL-C increased. Intergroup comparison showed a greater increase in HDL-C (p less than 0.05) and in the HDL-C/LDL-C ratio (p less than 0.01) in the ketanserin group as compared with the propranolol group.

Body Weight↗
PubMed1987

[Polyamines and cardiovascular hypertrophy in experimental hypertension].

UNLABELLED: Biochemical mechanisms which control cardiac and vascular response to hypertension are still unclear. Modifications of polyamines (putrescine, spermine, spermidine) may play a role in this phenomenon, since these molecules have been shown of importance in the control of tissue growth. Ornithine Decarboxylase (ODC) catalyses the first and probably the rate limiting step in the biosynthesis of the polyamines. We thus attempted to detect modification of ODC activity in renovascular hypertension in the rat (G1K-1C) and tried to correlate hypertrophic response and ODC activity in the aorta (Ao), the left (LV) and the right (RV) ventricles. In this experimental model, the aortic ODC activity increased at day 1 and 2, after clipping the renal artery, whereas in the LV the ODC activity increased after day 3 but stay high at least until day 7. The peak of ODC activity comes before the increase in DNA synthesis which occurs at day 4 in Ao, and the increase in protein turnover observed at day 7 in LV. No significant variation of ODC activity neither changes in DNA or protein biosynthesis rate are observed in the RV. In parallel with changes in ODC activity, an increase in spermidine and spermine content and mainly in the spermidine/spermine ratio is observed in the Ao and the LV confirming stimulation in polyamine biosynthesis in hypertensive tissues. IN CONCLUSION: increase in ODC activity is observed only in these tissues that will develop hypertrophy or hyperplasia and this modification is observed before any increase in nucleic acids or protein tissues content or turnover rate.

Animals↗