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Biomedical subjects

E Comoy

Publications and source records attributed to E Comoy.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Plasma renin and catecholamine activity in pheochromocytoma].

We have studied the renin aldosterone system and plasma catecholamines in 26 untreated patients with phaeochromocytoma, 21 untreated patients with primary hypertension, and in 10 normal volunteers. Blood pressure (mmHg), plasma renin activity (radioimmunoassay of angiotensin I, ng/ml/h), plasma concentrations of aldosterone (direct radioimmuno-assay, pg/ml), adrenaline and noradrenaline (radioenzymatic assay with catechol-O-methyl transferase, pg/ml) were measured after 1 h of supine rest, 5 mn upright and after walking 1 h. Seven patients with phaeochromocytoma were subsequently given 400 mg acebutolol bid for 3 days, and five were given 1 mg/kg captopril. Supine renin activity was higher in phaeochromocytoma than in primary hypertension and in volunteers (average 2.54, 1.03 and 0.85, F = 7.1, p less than .01) and rose higher after walking (mean increase 3.84, 1.19 and 0.68 respectively, F = 6.3, p less than .01). Aldosterone was higher after walking in phaeochromocytoma than in primary hypertension (534 vs 275 pg/ml, p = .03). Differences in renin and aldosterone could not be explained by age, natriuresis or plasma volume. Catecholamines were as expected much higher in phaeochromocytoma than in the other two groups (p less than .01). At variance with primary hypertensive and normal volunteers, renin was tightly correlated with noradrenaline in patients with phaeochromocytoma (r' = .54, r' = .60, and r' = .74 in supine position, after standing and after walking 1 h, p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed1985

Hypertensive responses during operation for phaeochromocytoma: a study of plasma catecholamine and haemodynamic changes.

Virtually all patients undergoing resection of a phaeochromocytoma exhibit hypertensive crises at some period perioperatively. In order to study the events associated with hypertensive responses, cardiovascular variables were measured with a Swan-Ganz pulmonary artery catheter and plasma catecholamine levels were determined simultaneously in eight patients during surgery for phaeochromocytoma. Hypertensive responses requiring vasodilator treatment occurred in five patients, i.e. systolic blood pressure (BP) greater than 200 mmHg for more than 1 min. Transient elevation, at least in systolic BP, to greater than 200 mmHg occurred in all patients. Hypertensive responses were identified associated with two circumstances: the first in association with noxious stimuli, i.e. intubation, skin incision, etc., but were not generally accompanied by an elevation in plasma noradrenaline and adrenaline levels; the second occurring during tumour manipulation were more severe and were always accompanied by elevated plasma noradrenaline and adrenaline levels. Transient left ventricular dysfunction, defined by increased pulmonary capillary wedge pressure (PCWP) and decreased cardiac index (CI) secondary to a marked increase in systemic vascular resistance (SVR), was observed in four patients during palpation of the tumour, while one patient exhibited more marked and prolonged ventricular dysfunction. It is concluded that hypertensive responses associated with noxious stimuli may be controlled with deep anaesthesia while those due to tumour manipulation cannot be prevented and are best treated with vasodilators.

Adrenal Gland Neoplasms↗
PubMed1984

Immunological and enzymatic studies of erythrocytic delta-aminolevulinate dehydratase. Comparison of results obtained in normal and lead-exposed subjects.

The delta-aminolevulinate dehydratase (ALA.D) quantitative assay on a centrifugal fast analyser showed that subjects whose blood-lead level varies between 30 and 75 micrograms/100 ml (1.5 to 3.75 microM/l) react to blood intoxication by synthesizing de novo an amount of enzyme correlating to blood-lead levels. At higher concentrations, the reactional synthesis occurs very rarely. These results suggest that enzyme is constitutive, but also inductible as soon as its substrate accumulates; this last ability may disappear at high blood-lead levels: a hypothesis is proposed thereafter.

Adult↗
PubMed1984

Two-dimensional electrophoretic analysis of cytosols from human breast tumors: optimal migration conditions.

In an examination of cytosols from human breast tumors, we performed two-dimensional electrophoretic analysis. Several migration conditions were tried in a search for a homogeneous repartition of cytosolic proteins. The most workable gels were obtained with a 4.40 to 8.05 pH gradient in the first dimension and a homogeneous 125 g/L acrylamide/sodium dodecyl sulfate gel, 1 mm in thickness, in the second dimension. The practicability of this method is discussed.

Breast Neoplasms↗
PubMed1983

Pharmacokinetic aspects of guanfacine withdrawal syndrome in a hypertensive patient with chronic renal failure.

The unusual observation of a withdrawal syndrome due to guanfacine in a hypertensive patient with chronic renal failure led to a study of the kinetics of the drug in this patient. The principal pharmacokinetic parameters of guanfacine were greatly altered, with extended biotransformation and a decrease in the half-life compared to the values observed in other cases of severe renal insufficiency. Associated treatment with phenobarbital had had a considerable effect, as shown by the results of a further kinetic study 2 months after withdrawal of the phenobarbital. The findings then were in good agreement with reference values which strongly suggests a consequence of the enzyme inducing effect of phenobarbital. Advice about the dosage regimen in such cases is given.

Female↗
PubMed1983

[Effects of the administration of somatostatin 14 in the carcinoid syndrome. Clinical and biological study of 2 cases].

The effects of synthetic cyclic somatostatin 14 were studied in two patients with the carcinoid syndrome. The 3-hour intravenous administration of somatostatin (250 micrograms X h-1), a) resulted in the disappearance of flushing in the first patient but was without any clinical effect in the second subject who remained chronically colored; b) lowered plasma levels of motilin, prostaglandins (E1, E2 and F2 alpha) and to a lesser extent of catecholamines in both patients whereas the serotonin level was not altered; c) was followed by a rebound effect with recurrence of severe flushing in the first patient and was associated with a dramatic increase of prostaglandin, substance P and catecholamine levels in both patients. The inhibitory effect of somatostatin and the occurrence of a rebound effect at the end of infusion were confirmed by infusing somatostatin (6 mg per day) during 48 h in the first patients. These results: a) show that somatostatin is an effective drug in carcinoid syndrome with severe flushing; b) confirm that several mediators are affected in carcinoid syndrome. However it could not be excluded that increased circulating levels of prostaglandins, substance P and catecholamines may represent unrelated secondary events; c) suggest that somatostatin primarily inhibits the release rather than the synthesis of tumor products. Owing to the severity of the rebound effect, treatment of the carcinoid syndrome with somatostatin must be undertaken with precaution until specific long-acting analogs are available.

Aged↗
PubMed1983

Plasma renin activity, blood uric acid and plasma volume in pregnancy-induced hypertension.

UNLABELLED: Plasma renin activity (PRA), plasma aldosterone (PA), blood uric acid (BUA), plasma concentrations of catecholamines (Pcat) and plasma volume (PV) were measured simultaneously in 24 patients with pregnancy-induced hypertension (PIH). This hypertensive group was divided into labile (LH) and persistent hypertension (PH) groups according to the response of their blood pressure to home bed rest. Compared to normal theoretical values, PV was decreased in both hypertensive groups (LH = -7%; PH = -14%). Compared to a control group (C) of 16 normotensive pregnant women, PRA was higher in LH and lower in PH whereas PA was lower in both hypertensive groups. BUA was higher than in C in both hypertensive groups. No difference in PCat was found between the three groups. In the PH group negative correlations were found between BUA and PRA, as well as between BUA and PV but no correlation between PRA and PV nor between Pcat and BUA were found. IN CONCLUSION: LH and PH are two pathophysiologically different entities in PIH. In PH renin secretion is not appropriate to hypovolaemia and therefore not primarily involved in the pathogenesis of hypertension. Hypovolaemia may play a role in the increase of BUA in PIH.

Adult↗
PubMed1983

[Metabolism of catecholamines in the clinical biochemistry of hypertension].

The object of this study was to review the state of methods of investigating the mmetabolism of catecholamines in the biochemical study of hypertension. A comparison between blood and urinary parameters would seem to show urinary metanephrine levels to be the most discriminating biochemical indicator of pheochromocytoma: this parameter is particularly valuable when pheochromocytoma is associated with normal blood pressure, a situation in which the circulating catecholamine levels are usually unchanged. Three recent aspects of this diagnosis, the development of which may provide new information, are discussed: differentiation between free and conjugated catecholamines, evaluation of platelet amines, the clonidine test. The study of the métabolism of catecholamines in non-tumoral hypertension is also considered but the problems in performing and interpreting these tests are much more difficult.

Adrenal Gland Neoplasms↗
PubMed1982

Renin angiotensin aldosterone system and adrenergic system in normotensive and hypertensive pregnancy.

We have measured simultaneously plasma renin activity (PRA), aldosterone and catecholamines in the plasma of 3 groups of pregnant women after the 20th week: group 1 of 16 normotensive controls, group II of 17 women with rest responding hypertension (RRH), group III of 18 women with permanent hypertension (PIH). All the patients were ambulatory on a normal salt diet. PRA was significantly higher in the RRH than in the control and PIH groups (15,8 +/- 2,3ng/ml/l versus 6,7 +/- 0,5 and 8,9 +/- 0,9 respectively). Plasma epinephrine (PE) and norepinephrine (PNE) were significantly higher in the PIH than in the control and RRH groups (respectively 135 +/- 28 pg/ml versus 56 +/- 13 and 63 +/- 17 for PE and 387 +/- 91 versus 206 +/- 32 and 200 +/- 47 pg/ml for PNE). In the PIH group there was a negative correlation between PRA and blood uric acid. It is concluded that the adrenic system is activated in PIH whereas the renin angiotensin system is activated in RRH of pregnancy.

Adult↗
PubMed1982

[The renin-angiotensin-aldosterone system and the adrenergic system in normal pregnancy and hypertension induced by pregnancy].

Plasma renin activity (PRA), plasma aldosterone (PA) and plasma catecholamines were measured in 3 groups of women with pregnancy of 20-38 weeks: group I of 16 normotensive controls, group II of 17 women with rest responding hypertension (RRH) and group III of 18 women with permanent hypertension (PH) (supine blood pressure greater than 140-90 mmHg after 8 days of rest, disappearing after delivery). Studies were realized on fasting ambulatory women on a normal salt diet. PRA (mean +/- SEM) was significantly higher in the RRH group than in the control and PH groups (15,8 +/- 2,3 ng/ml/h versus 6,7 +/- 0,5 and 8,9 +/- 0,9). PA was higher but not significantly in the RRH group (736 +/- 122 versus 533 +/- 52 and 502 +/- 103 pg/ml). Plasma epinephrine (PE) and norepinephrine (PNE) were significantly higher in the PH than in the control and RRH groups. 135 +/- 28 pg/nl versus 56 +/- 13 and 63 +/- 17 for PE and 387 +/- 91 versus 206 +/- 32 and 200 +/- 47 pg/ml). These data suggest that PH is linked with activation of the adrenergic system whereas RRH is linked with activation of the RAA system.

Aldosterone↗
PubMed1981

Biochemical tests for diagnosis of phaeochromocytoma: urinary versus plasma determinations.

Fifteen patients with hypertension due to phaeochromocytoma and 35 controls with essential hypertension were studied to assess the diagnostic value of urinary and plasma biochemical determinations in phaeochromocytoma. In every case of phaeochromocytoma the urinary concentration of vanillylmandelate, metanephrines, or adrenaline plus noradrenaline was diagnostic of the disease irrespective of whether the patient was normotensive or hypertensive at the time. Plasma determinations of adrenaline and noradrenaline, however, gave falsely negative results on three occasions. These findings suggest that urinary biochemical determinations--particularly of metanephrines--are more reliable than plasma catecholamine measurements as a test for phaeochromocytoma. The test is particularly useful in patients with intermittent hypertension.

Adrenal Gland Neoplasms↗
PubMed1981

Lack of antagonism in the antihypertensive effects of clonidine and prazosin in man.

1. In four patients, whose hypertension was not controlled (supine blood pressure greater than 150--90 mmHg) by addition of 5 mg/day of prazosin to previous treatment (diuretics and beta-blockers), clonidine (150--450 microgram/day) led to control of hypertension in three cases. 2. In ten patients whose hypertension was not controlled by a treatment including clonidine (300--450 microgram/day), the progressive addition of prazosin to a maximal dose of 4--22.5 mg/day led to control of hypertension in nine cases (mean supine blood pressure decreased from 174--102 to 144--88 mmHg). 3. In 13 hospitalized patients, clonidine was abruptly interrupted whereas prazosin was continued. Mean blood pressure (+/- SEM) rose from 145 +/- 1/85 +/- 2 to 169 +/- 7/104 +/- 5 mmHg 48 h after clonidine withdrawal whereas plasma noradrenaline and adrenaline rose from 328 to 758 pg/ml and from 75 to 137 pg/ml. No subjective symptoms were noted. There was a negative correlation between blood pressure increase and the dose of prazosin. 4. It is concluded that (a) there is no antagonism between clonidine and prazosin in their antihypertensive action in man when used at usual clinical doses, (b) a protective effect of prazosin against an eventual clonidine withdrawal syndrome is suggested by the negative correlation between blood pressure increase and the dose of prazosin.

Adult↗
PubMed1980

Two cases of shoshin beri beri with hemodynamic and plasma catecholamine data.

Two fulminant forms of beri beri ("shoshin beri beri") have been the subject of detailed study; circulating catecholamines reached very high levels. The evolution of hemodynamic parameters after treatment with thiamin is described. One case died and the histological lesions corresponded to those of "chronic congestive beri beri".

Adult↗
PubMed1980

[Orthostatic hypotension in tetraplegic patients (author's transl)].

Blood pressure regulation was studied in nine patients with tetraplegia following total cervical section. Ten minutes after placing the patients in an inclined position at 30 degrees there was a marked reduction in blood pressure, an increase in heart rate, and absence of increased peripheral resistance. Valsalva's maneuver was pathological in all cases (lack of overshoot). Circulating catecholamines were measured in five cases and were low in decubitus and did not react to orthostatism. Plasma renin and aldosterone levels were at the upper limits of normal and reacted strongly to orthostatism. Marked hypersensitivity to exogenous angiotensin and noradrenaline was observed in all cases. These modifications result from section of the sympathetic efferent pathways. High plasma renin levels and their increase during orthostatism are not incompatible with these findings and probably result from intervention of renal baroreceptors. Whatever the mechanism involved, this increase in plasma renin activity could play an important role in the control of blood pressure in tetraplegic patients.

Adolescent↗
PubMed1979

[Plasma renin and noradrenalin levels during hypotensive therapy using acebutolol (author's transl)].

The effects of acebutolol (800 mg per day for three days) on pulse rate, blood pressure, plasma noradrenaline and plasma renin activity were measured in nine patients with essential hypertension, at rest in a horizontal position, after five minutes standing upright and after walking for one hour. Acebutolol reduced pulse rate, blood pressure and plasma renin activity in all three positions. Treatment has no influence on plasma noradrenaline in a horizontal position, but significantly reduced its orthostatic stimulation. The inhibition of noradrenergic response to an orthosatic position is compatible with a central or presynaptic effect of acebutolol. This effect would not appear to be essential to its antihypertensive action since acebutolol reduced blood pressure but not plasma noradrenaline in a horizontal position. Blood pressure response to treatment was positively correlated to initial values of plasma renin activity measured after walking for one hour and plasma noradrenaline measured after five minutes in an orthostatic position. On the basis of this correlation, measurement of these two hormonal indices is of predictive value, within the limits of a short period of treatment with acebutolol and strictly defined hospital conditions.

Acebutolol↗