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Biomedical subjects

M Lebel

Publications and source records attributed to M Lebel.

At least 91 records · Page 5Linked to original sources
PubMed1982

Renal prostaglandins in borderline and sustained essential hypertension.

To assess the implication of renal prostaglandins in the pathogenesis of essential hypertension, urinary PGE2 and PGF2 alpha were measured in 22 control subjects (11 males) and in 58 patients (33 males) with borderline and sustained essential hypertension under strictly control conditions. Although the mean PGs urinary excretion in essential hypertension was not significantly different from control subjects, 12% of the patients had very low PGE2 levels comparable to subjects receiving prostaglandin synthetase inhibitors. There was no difference in urinary PGE2 between borderline and sustained essential hypertension. Urinary PGF2 alpha values were also not significantly different in normal subjects and in hypertensive patients, although four patients (2 of each sex) had excessively elevated PGF2 alpha. There was no significant correlation between the two urinary prostaglandins and blood pressure levels, plasma renin activity, urinary volumes and sodium excretion. These results suggest that with the exception of a small percentage of patients, the renal production of PGE2 and PGF2 alpha are comparable in normal and in hypertensive patients; the production rates of these two compounds are also not influenced by the degree or stage of hypertension.

Adult↗
PubMed1981

Alteration of the volume-renin component in borderline essential hypertension.

Interrelations between blood pressure, circulatory volumes and the renin-angiotensin system were studied in 15 normal subjects and in 25 young patients with borderline hypertension after equilibration on controlled sodium intake. Total blood and plasma volumes were consistently lower and plasma renin activity higher in borderline hypertensive as compared to normotensive controls. The decreased volumes were inversely correlated with blood pressure and plasma renin activity, but no correlation was found between blood pressure and plasma renin activity or the product of circulating renin and volumes. The fact that blood pressure and plasma renin activity were independently correlated to circulating volumes but did not correlate between themselves would suggest a common causal factor for the three observed phenomena: elevated renin, decreased volume and borderline hypertension; these anomalies of the volume-renin axis might be mediated through the well documented hyperresponsiveness of the sympathetic nervous system in these patients.

Adolescent↗
PubMed1981

[The evaluation of the Harrington technique in the treatment of double-curved scoliosis (author's transl)].

Double-curved scoliosis was present in 18.5 of 750 scolioses operated on at the St. Justine Hospital in Montreal. 128 cases were reviewed with a follow up of more than 3 years. Pre-operative curves measured 61 and 58 degrees on average and post-operative curves measured 27 and 23 degrees. At the time of review, the curves were 39 and 36 degrees. The loss of correction varied with the age of the patient and the severity of deformity. The technique of early ambulation improved the post-operative results. However, it was concluded that compression rods did not provide a better correction of the curve or of the thoracic kyphosis.

Adolescent↗
PubMed1981

Renin responsiveness to furosemide in the homotransplanted kidney.

Plasma renin activity (PRA) was measured after repetitive furosemide stimulations in 16 normotensive homotransplanted patients who previously had bilateral nephrectomies. The percentage PRA response to furosemide was very low (34%) in the immediate period after transplantation, but increased progressively with time to a level after one year (111%) which was not statistically different from age and sex matched control subjects. A significant correlation was found between the percentage PRA increase and the number of weeks after transplantation (r = 0.48, P less than 0.01). These data indicate that the juxtaglomerular cell responsiveness to furosemide is quantitatively time dependent after transplantation, and it is a factor that should be considered in the evaluation of renin-angiotensin system in such patients.

Adult↗
PubMed1980

Diminished urinary prostacyclin metabolite in essential hypertension.

1. Urinary excretion rate of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), a stable nonenzymatic transformation product of prostacyclin (PGI2), was measured in 13 patients with sustained essential hypertension and in nine normotensive control subjects by a specific radioimmunoassay. 2. Patients with essential hypertension had significantly lower 6-keto-PGF1 alpha excretion rates irrespective of their sex, but in both groups urinary 6-keto-PGF1 alpha was lower in females. 3. Sodium excretion was significantly correlated with urinary 6-keto-PGF1 alpha only in hypertensive subjects. There was also a positive correlation between 6-keto-PGF1 alpha and urine volume in control subjects and in hypertensive patients. 4. If diminished urinary 6-keto-PGF1 alpha reflects suppressed endogenous PGI2 production, a deficiency in this important vasodepressor substance in essential hypertension may contribute to the pathogenesis of this disease.

Adult↗
PubMed1980

Renal revascularization as treatment for malignant hypertension.

Twelve patients critically ill with accelerated or malignant hypertension caused by atheromatous renal artery disease were treated by renal revascularization because an intensive program of medical treatment had failed. Seven patients had unilateral stenosis, five patients had bilateral lesions. This aggressive approach was beneficial to all the patients; there was no operative mortality and morbidity was minimal. Blood pressure was adequately controlled in all 12 patients. After a mean follow-up of 42 months, renal function was improved or stable in 10 patients but had deteriorated slightly in 2. Interestingly, one patient who had a higher renin activity in his contralateral nonstenotic kidney was much improved by correction of only the stenosis. The authors recommend early surgical intervention in severe renal artery lesions in cases of accelerated or malignant hypertension refractory to vigorous medical treatment or with rapidly progressive renal failure. An occluded renal artery can be revascularized if the kidney has no gross evidence of infarction, has viable glomeruli and if distal arteries and their intrarenal branches are intact. Reduction of blood pressure and stabilization or restoration of renal function can be expected.

Adult↗
PubMed1977

Adenocarcinoma of the kidney and hypertension: report of 2 cases with special emphasis on renin.

Renin studies were done on 2 patients with adenocarcinoma of the kidney and hypertension. In 1 case plasma renin activity was high in the peripheral and renal veins, with a renal vein ratio of 1.7 favoring the side of the tumor. Nephrectomy cured the hypertension and renin values became normal. Tissue renin was elevated in the tumor and surrounding parenchyma. Acidification studies of tissue extracts failed to demonstrate the existence of big renin. In case 2 all renin values were normal and the blood pressure remained elevated after the operation. Although renin-secreting tumors remain an uncommon cause of malignant hypertension the condition should be recognized because it is potentially curable.

Adenocarcinoma↗
PubMed1977

Wicket spikes: clinical correlates of a previously undescribed EEG pattern.

From an analysis of the electroencephalograms of 4,458 patients who underwent recording during both wakefulness ans sleep, through the years 1969 to 1975, wicket spikes-- recorded in 39 patients-- may be described as follows: They were found during both wakefulness ans sleep, almost exclusively in adults. Their cardinal feature is a changing mode of occurrence through any single recording: from intermittent trains of more or less sustained, arciform, discharges resembling mu rhythm, to sporadic, urinary, single spikes. When occurring singly, wicket spikes can be mistaken for anterior or middle temporal spikes, since they predominate in eith er area, and since they share with them other characteristics such as amplitude (60 to 210 microvolts), polarity (surface negative) duration, and configuration. Wicket spikes should not be considered interictal abnormalities; they do nor correlate with epilepsy or with any particular symptom complex.

Electroencephalography↗
PubMed1977

[Headache simulating meningeal hemorrhage].

That migraine can present with a severe headache of sudden onset mimicking that of subarachnoid hemorrhage--the so-called "complicated migraine with meningeal manifestations" of Pearce and Foster--is not readily appreciated. Over the past three years, seven patients have been referred to us with a presumable diagnosis of subarachmoid hemorrage. In each one of these patients, the clinical features (an explosive headache, relapsing in three, and a normal neurological examination) together with appropriate laboratory investigations (cerebro-spinal fluid analysis, electroencephalography, echoencephalography, brain scan, arteriography, pneumoencephalography) have ruled out the diagnosis of subarachnoid hemorrhage, as well as less common causes of explosive headaches such as ball-valve tumors of the ventricular system, intra-cerebral hemorrhage, hemorrhage into a tumor. In three out of these seven patients, there was no history of migraine. Bening explosive headaches mimicking subarachnoid hemorrhage, occurring in patients with or without antecedents of migraine, are not as unusual as one might conclude from a review of the literature. Proper recognition of this syndrome is important since it might help to sort out those patients with explosive headaches who need not be submitted indiscriminately to risk-fraught procedures.

Adult↗
PubMed1976

Selective hypoaldosteronism: a study of steroid biosynthetic pathways under adrenocorticotrophin and angiotensin II infusion.

1. The functional integrity of the adrenal cortex has been tested in a case of selective hypoaldosteronism by adrenocorticotrophin (ACTH) and angiotensin II (AII) infusion. 2. During ACTH infusion a normal functioning zona fasciculata was indicated by the impressive increase of the ACTH-dependent plasma steroids; the aldosterone response was moderate. 3. During AII infusion the plasma aldosterone response was blunted with an unexpected dose-dependent increase in pregnenolone, resulting in abnormal decreasing progesterone/pregnenolone ratios during the infusion, suggesting a slow-down in the conversion of pregnenolone into progesterone. 4. This defect, a probable consequence of chronic renin deficiency on the zona glomerulosa, could be a contributing factor to the hypoaldosteronism.

Adrenal Cortex↗
PubMed1975

Plasma progesterone and aldosterone in pregnancy.

Plasma progesterone, aldosterone and renin activity were measured simultaneously in seven women during normal pregnancy. Beginning at the 2nd trimester and until approximately 4 weeks before delivery there was a constant increase in plasma progesterone concentration. There was a significant correlation between weight gain and duration of pregnancy and between weight gain and plasma progesterone concentration. There was also an increase in plasma aldosterone concentration although this was less consistent than that of progesterone. And there was a significant correlation between plasma progesterone and aldosterone concentrations and between the progesterone/aldosterone ratio and duration of pregnancy and weight gain.

Adolescent↗