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Biomedical subjects

F Mantero

Publications and source records attributed to F Mantero.

At least 199 records · Page 11Linked to original sources
PubMed1978

Plasma renin activity and urinary aldosterone in Cushing's syndrome.

The renin-angiotensin-aldosterone system has been evaluated in 19 patients with Cushing's syndrome due to bilateral adrenal hyperplasia and in 2 patients with unilateral adenoma. In the first group urinary aldosterone was within the normal limits with a mean of 8.3 +/- 1.86 microgram/24 h. Aldosterone excretion did not change significantly after furosemide administration, ACTH infusion or dexamethasone. Upright PRA was suppressed in 9/16 patients with a mean of 4.9 +/- 1.85 ng/ml/3 h and showed only a slight response to furosemide. Dexamethasone alone did not produce any change. Both aldosterone and PRA were to some extent stimulated by an association of dexamethasone and furosemide. In the 2 patients with adenoma, aldosterone excretion was also normal, but PRA was very elevated. From our data it is concluded that in Cushing's syndrome due to bilateral hyperplasia, PRA and aldosterone excretion are partially suppressed. From our results on plasma deoxycorticosterone and corticosterone concentration it seems unlikely that these mineralocorticoids are the major cause of this phenomenon. However, it may not be excluded that other yet unidentified hormones could play some role in the pathogenesis of hypertension and renin suppression in Cushing's syndrome.

Adolescent↗
PubMed1978

Plasma renin activity in coarctation of the aorta before and after surgical correction.

In 37 patients with coarctation of the aorta, arterial blood pressure and ambulant plasma renin activity (PRA) were determined before and, in 15 patients, after surgical correction. The systolic blood pressure was raised in all the cases and the diastolic pressure was raised in 30 patients. Ambulant PRA was increased in 11 patients when compared with normal subjects of similar age. Twelve of the 15 operated patients had a significant decrease of systolic pressure after operation. Eight had raised PRA, and in 7 of these PRA fell to normal after operation and the blood pressure also fell; in 1 patient the decrease of PRA was unaccompanied by a fall in blood pressure. Though there was no significant correlation between the changes in blood pressure and PRA after operation it seems possible from our results that the renin-angiotensin system may be activated and contribute to the raised arterial pressure which occurs in patients with aortic coarctation.

Adolescent↗
PubMed1976

Aldosterone regulation in primary aldosteronism: differences between adenoma and bilateral hyperplasia.

1. The diurnal patterns of plasma aldosterone, plasma renin activity (PRA), cortisol and adrenocorticotrophic hormone (ACTH) in the supine and in the upright position have been studied in fourteen patients with primary aldosteronism, five with adenoma and nine with bilateral hyperplasia. Blood samples were drawn at intervals from 6 h to 30 min. 2. Supine patients with an adenoma showed marked diurnal variations of aldosterone, with maximal values at 08.00 hours and minimal values of 18.00 hours and secretory spurts beginning after 02.00 hours. Plasma cortisol paralleled aldosterone, and ACTH seemed to anticipate aldosterone and cortisol variations; PRA remained unchanged. In patients with hyperplasia, aldosterone was significantly lower than in the adenoma group at 08.00 hours, and its decline during the day was less marked; fluctuations rather than secretory episodes were seen. 3. After patients assumed the upright posture, aldosterone remained unchanged or decreased in patients with adenoma, whereas it significantly increased in hyperplasia; PRA remained low, although a slight increment was seen in the latter group. The different response of aldosterone in the two groups was not modified by the administration of propranolol, apparently excluding a renin-dependent mechanism. On the other hand, dexamethasone seemed to affect the response of aldosterone to the upright posture in both groups; in adenoma there was a slight but significant increase, and in hyperplasia the usual rise was partially suppressed. 4. It is concluded that ACTH has a predominant role in regulating aldosterone secretion in primary aldosteronism due to adenoma, whereas its action in bilateral hyperplasia is only permissive.

Adenoma↗
PubMed1976

Urinary kallikrein excretion in Bartter's syndrome.

Urinary excretion of kallikrein has been studied in a patient with hypokalemic alkalosis, hyperplasia of the renal juxtaglomerular apparatus and hyperreninemia, secondary aldosteronism and resistance to the pressor effect of angiotensin II (Bartter's syndrome). Urinary kallikrein was found exceedingly high in several determination, whereas it was low in patients with essential hypertension and high in patients with primary aldosteronism. Urinary kallikrein decreased after spironolactone therapy. The rise of kallikrein excretion (which is not related to plasma renin) in this case is probably caused by a direct action of the chronic excess of plasma aldosterone; it could not be accounted for as secondary to natriuresis.

Adult↗
PubMed1976

[Effect of diazoxide on blood pressure, PRA and plasma aldosterone in hypertensive patients (author's transl)].

Intravenous diazoxide (300 mg) was administered to 29 hypertensive patients previously classified in subgroups according to their plasma renin and urinary aldosterone levels. The blood pressure was measured before and periodically after injection and plasma renin activity (PRA) and plasma aldosterone before and after 2 hours. The mean systolic and diastolic blood pressure fell notably from 193/118 to 155 93 mmHg; whereas PRA increased from 7.51 to 13.21 ng/ml/3 hrs and plasma aldosterone did not change significantly (71.3 and 102.8 ng%). Examining the individual sub-groups, a significant decrease in blood pressure was observed in 15 patients with low, posture unresponsive PRA, both in subjects with normal urinary aldosterone and those with surgically proven primary aldosteronism. In the former only the mean PRA showed a slight but sigificant increase, while in the latter the changes for both PRA and aldosterone were not significant. In the subgroups of patients with normal renin and urinary aldosterone the arterial pressure also significantly and promptly decreased. However, in this group the mean PRA substantially increased whereas the plasma aldosterone levels remained constant. The same blood pressure decline was observed in those patients with high PRA and aldosterone, including 1 case of pheocromocytoma. The mean PRA showed a further modest increase while the plasma aldosterone did not change significantly. These results indicate that the antihypertensive action of diazoxide is similar in the different types of hypertension (volume, vasoconstrictor or mixed form according to Laragh's classification), being independent of the basal plasma renin and aldosterone levels. Furthermore, the response of the blood pressure to diazoxide is not related in any way to the induced changes in PRA and plasma aldosterone values.

Adrenal Gland Neoplasms↗
PubMed1976

[Indications for study of adrenal function by measurement of the cortisol secretion rate].

Results of routine methods for measurements of plasma cortisol and his urinary metabolites have been comparated with those of cortisol secretion rate (CSR) measured by simple isotopic dilution; the latter appears for his specify and precision, to be the most suitable for an exact evaluation of cortisol production by the adrenals. In normal subjects CSR resulted slightly lower than those reported in the literature; in obese subjects CSR was slightly higher than in normals, also when it was related to the urinary creatinine. In the patients with Cushing's syndrome, CSR was considerably higher, with no overlap with the obese subjects. The CSR was also useful in showing values lower than normal, in hypopituitarism, and in confirming hormone abnormal findings in thyroid diseases.

Adolescent↗
PubMed1975

Primary aldosteronism due to a malignant ovarian tumor.

A case of a young woman with the syndrome of primary aldosteronism and malignant ovarian tumor is reported. Hormone studies revealed extremely high urinary aldosterone, undetectable plasma renin activity, elevated plasma 17beta estradiol and testosterone, and low plasma FSH and LH. Plasma cortisol and urinary 17-hydroxycorticoids were at the upper normal limits. Autopsy disclosed an ovarian tumor, histologically an arrhenoblastoma, with polymorphic aspects. The adrenal glands grossly were normal. Aldosterone was found by the double radioisotopic technique in the neoplastic tissue.

Adrenal Glands↗