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Biomedical subjects

M Chaignon

Publications and source records attributed to M Chaignon.

At least 55 records · Page 3Linked to original sources

[The role of the venous reservoir in maintaining arterial pressure during hemodialysis. Effect of dihydroergotamine].

Hemodialysis has been reported to produce a decrease in cardiac output partially related to a peripheral relocation of blood volume. In order to further evaluate this hypothesis, the hemodynamic effects of dihydroergotamine (DHE), a veino-constrictor drug, were investigated in 5 patients undergoing hemodialysis. Body weight, total blood volume, arterial blood pressure, cardiac output and heart rate were obtained before (period A) and immediately after hemodialysis: before (period B) and after an acute infusion of DHE (period C); studies were performed in supine then in tilted position. During period B, cardiac index decreased by 27% (p less than 0.05) and stroke index by 35% (p less than 0.02). Acute infusion of DHE produced a significant increase in cardiac index (+ 18%, p less than 0.05), stroke index (+ 28%, p less than 0.05) and blood pressure (+ 20%, p less than 0.05). These results indicate that the hemodynamic alterations induced by hemodialysis may be partially reversed by contraction of the capacitance system following DHE infusion.

Adult↗

[Long term treatment of resistant hypertension with captopril (author's transl)].

The orally active angiotensin converting enzyme inhibitor SQ 14225 (captopril) was administered to 14 hypertensive patients resistant to conventional therapy. A marked antihypertensive effect was observed; all the patients were responders and blood pressure decreased by more than 20% in 13 out of them. Subjective tolerance was very good. Untoward effects of an immuno-allergic type have been noticed in 30% of these cases but disappeared in all instances when daily doses of the drug had been reduced, allowing maintenance of the treatment. Plasma renin activity increased during captopril administration but no relationship appeared between pretreatment plasma renin activity and the extent of blood pressure response to the drug. The use of captopril must be considered in severe and resistant hypertension but careful monitoring of this treatment is needed.

Adult↗

[Clinical pharmacology of prazosin in arterial hypertension with chronic renal insufficiency].

The pharmacokinetics of prazosin were studied in 10 patients (7 male and 3 female, Group I) with permanent hypertension and chronic renal failure (serum creatinine 40,5 +/- 5,9 mg/l) and in 10 normal subjects (10 male, Group II). Each patient received a single oral dose of 2 mg of prazosin; serum levels were studied at regular intervals over a ten hour period by spectrofluorometry Clinostatic blood pressure was measured with a mercury manometer in the patients in Group I. The rate of absorption of prazosin was identical in the two groups (t max: I,3 +/- 0,2 h and I,6 +/- 0,4 h). Maximal serum concentrations were significantly higher in Group I (33,5 +/- 3,7 microgram/1 compared to 22,0 +/- 2.5 microgram/l, p less than 0,02) as was the surface under the serum concentration curve plotted against time (206,I +/- 31.I microgram.h.l-1 compared to 99,9 +/- 12,3 microgram.h.l-1, p less than 0,01). Prazosin induced a significant fall in systolic and diastolic blood pressure (-19% and -23% respectively, p less than 0.001) in Group I, 90 minutes after administration, associated with a moderate rise in heart rate (+16%, p less than 0.01). The variation of blood pressure induced by prazosin correlated closely with its serum concentration (p less than 0.001). These results suggest that the bioavailability of prazosin is significantly higher in chronic renal failure and that a reduction of the daily dose should be envisaged in these patients on long-term therapy.

Adult↗

[Renovascular hypertension and beta blockers. Theoretical and practical implications].

Beta blockade was instituted in 10 patients with renovascular hypertension due to renal artery stenosis or thrombosis. The treatment was very effective in unilateral stenosis with a normal contralateral kidney (2 kidney Goldblatt) and in fibromuscular dystrophy of the renal artery. On the other hand many failures were observed in hypertension with a single kidney (1 kidney Goldblatt) and in renovascular hypertension with complex lesions or associated renal failure. Although a clear relationship was often observed between the increased plasma renin activity and the antihypertensive effect of beta blockade, this association was sometimes completely erroneous. Beta blockade, which is easy to perform, should be tried out systematically in renovascular hypertension, but, when no result is observed, this therapeutic test should not exclude surgical management thereafter.

Adrenergic beta-Antagonists↗

[Acebutolol in the treatment of arterial hypertension. Clinical study].

Fifty hypertensive patients were given a beta-blocker, acebutolol, alone or in association with other hypotensive drugs, in an open therapeutic trial lasting for a year. The results of treatment were considered to be good or moderate in 74 p.cent of the patients. Treatment failures were recorded in 26 p.cent. The mean dosage of acebutolol was 10 mg/kg (maximum 22 mg/kg) and the drug was very well tolerated. Hypertension with an increased cardiac index and reno-vascular hypertension with increased plasma renin activity are good indications for acebutolol.

Acebutolol↗

[Test with trinitrine. Clinical evaluation of the beta anti-adrenergic effect of acebutolol in arterial hypertension].

The beta-adrenergic stimulation test with nitroglycerin, described by Fitzgerald, was used to monitor antihypertensive treatment with the beta-blocker acebutolol in 30 hypertensive patients. The nitroglycerin-induced tachycardia was reduced by acebutolol and this allowed the degree of beta-blockage to be estimated. It would also be possible, by tests performed before treatment, to select hypotensive patients who could be highly responsive to beta-adrenergic blockers, for whom there are the best prospects of success.

Acebutolol↗

Premonitory sign of heart block in acute posterior myocardial infarction.

The appearance of the ARS complex in leads V3R and V4R was analysed in a series of 94 patients with acute posterior myocardial infarction. The cases of posterior myocardial infarction with direct signs of injury (ST segment elevation with a rise of 0.5 mm or more of point F and/or QS pattern) in leads V3R and/or V4R were complicated three times as often by atrioventricular block as those in which such signs were absent (66% and 22%, respectively; P smaller than 0.001). When one of these signs was present in leads V3R and/or V4R, the disorder of conduction was "severe" (complete atrioventricular block or sinotrial block with pauses) in half the cases and "unstable" (bradycardia below 50 beats/min; ventricular pause with or without syncope; widening of QRS complex; ventricular hyperexcitability) in one-third, justifying the introduction of a stimulating catheter. Such disorders were found, respectively, only 1 in 7 (14%), and less than 1 in 10 (8%) when these signs were absent (P smaller than 0.001). The association of ST segment elevation and QS pattern was rarer (15 cases) than the isolated finding of either sign. It was found in the most severe disorders of atrioventricular conduction. The changes observed in leads V3R and/or V4R before the appearance of atrioventricular block enable one to predict which patients with posterior myocardial infarction are the most likely to develop atrioventricular block. These electrocardiographic features seem to indicate septal involvement.

Adult↗

[Hemodynamic and hormonologic basis of the treatment of arterial hypertension].

The efficiency and the variety of drugs used in the treatment of arterial hypertension demand that the various disorders responsible for the blood pressure increase be well individualized. The study of the haemodynamic and hormonal factors and of their interelations in the patients provides interesting informations which make it possible to classify the hypertensive subjects according to physiopathological criteria. Starting from these data, it is possible to consider a rational treatment by selecting the drugs acting specifically on the anomalies to be corrected.

Adrenergic beta-Antagonists↗