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Biomedical subjects

F Mantero

Publications and source records attributed to F Mantero.

At least 109 records · Page 6Linked to original sources
PubMed1991

Ketoconazole treatment in Cushing's syndrome: experience in 34 patients.

OBJECTIVE: Ketoconazole treatment of Cushing's syndrome has been reported in single cases and a few small groups of 5-8 patients. We report our experience in 34 patients. DESIGN: Clinical study, with pretreatment and post-treatment evaluations. PATIENTS: Out of 67 patients with Cushing's syndrome admitted during the last 6 years, 34 (28 females/six males; age range 14-67 years) received ketoconazole as a palliative treatment due to severe clinical conditions or management of the disease while awaiting results of definitive therapy. MEASUREMENTS: Urinary cortisol, plasma cortisol and ACTH, and routine chemistry were measured every week for 4 weeks, and then once a month. RESULTS: Comparing the last values (mean +/- SEM) during treatment with baseline, urinary cortisol decreased from 1296 +/- 176 to 270 +/- 69 nmol/d (n = 34; P less than 0.001); plasma cortisol decreased from 672 +/- 31 to 549 +/- 35 nmol/l (n = 34; P less than 0.001). For patients with pituitary-dependent Cushing's syndrome, urinary cortisol decreased from 1073 +/- 126 to 200 +/- 21 nmol/d (n = 28; P less than 0.001) while plasma ACTH changed from 12.5 +/- 1.3 to 11.3 +/- 0.8 pmol/l (n = 26; not significant). Twelve patients were treated for more than 6 months, and those with pituitary-dependent disease all received pituitary radiation therapy, except the two who eventually escaped pharmacological control. One additional patient with adrenal carcinoma and one with ectopic ACTH syndrome showed lack of control of urinary cortisol levels. Ketoconazole was withdrawn within the first week in two patients for allergic reaction and acute liver toxicity. Other side-effects included: asymptomatic liver function abnormalities in three patients; gastrointestinal symptoms in four; worsening of gynaecomastia in one. Rapid clinical improvement was observed together with the normalization of urinary cortisol levels, with regression of symptoms such as diabetes mellitus, hypertension, hypokalaemia, and restoration of well being. CONCLUSIONS: These data confirm that ketoconazole is valuable in the management of hypercortisolism, provided that patients are closely watched to exclude those who may develop liver toxicity and to prevent the occurrence of adrenal insufficiency.

Adolescent↗
PubMed1991

Deletion within the CYP17 gene together with insertion of foreign DNA is the cause of combined complete 17 alpha-hydroxylase/17,20-lyase deficiency in an Italian patient.

The molecular basis of 17 alpha-hydroxylase/17,20-lyase deficiency syndrome in a 14-yr-old 46,XY Italian patient was investigated by amplification, subcloning, and sequencing of specific exonic sequences from genomic DNA samples. A homozygous mutation, consisting of a 518-basepair (bp) deletion combined with a 469-bp insertion, was identified in the CYP17 gene of the patient. The deletion spans much of exon II, the whole intron 2, and a portion of exon III. A part (156 bp) of the inserted sequence shows 95.5% identity to the nuclear antigen-binding site on Marek disease virus DNA and sequences found in rearranged mitochondrial DNA of rat hepatoma cells. A similar degree of sequence identity (99%) was also found between the above sequences and part of the lac operon of E. coli. The inserted sequence is lacking the BamHI site in intron 2 of CYP17 and contains an in-frame stop codon (TAA). Thus, the mutated gene encodes a truncated nonfunctional steroid hydroxylase, giving rise to symptoms associated with complete combined 17 alpha-hydroxylase/17,20-lyase deficiency. The family history revealed that the patient is the child of a consanguineous marriage and has two genotypically and phenotypically female sisters also suffering from symptoms of the disease. Investigation of genomic DNA from these sisters revealed that in each case both CYP17 alleles contained the same mutation. On the other hand, the parents were found to be heterozygous for this mutation. The insertion could not be found in DNA from normal individuals or in the CYP17 gene of other Italian patients with the 17 alpha-hydroxylase deficiency syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

In vitro evidence for local generation of renin and angiotensin II/III immunoreactivity by the human adrenal gland.

The adrenal gland of various mammalian species has been shown to contain all the components of a functional renin-angiotensin system. We investigated the existence of this local system in human adrenal tissues surgically obtained. Eight normal adrenals (cortex and medulla) and 6 aldosterone-producing adenomas (aldosteronomas) were examined. Minced tissues were superfused over 270 min, and 15-min fractions were collected. In the perfusates, active renin was measured by immunoradiometric assay with human anti-renin monoclonal antibodies; immunoreactive angiotensin II/III and aldosterone were measured by radioimmunoassay. Adrenal tissues, either normal or pathological, were found concomitantly to release renin, angiotensin II/III and aldosterone. The pattern of this spontaneous release exhibited a pulsatile character. The total amount of renin and angiotensin II/III secreted during superfusion clearly exceeded the tissue content (determined by extraction). Addition of the angiotensin-converting enzyme inhibitor quinaprilat (4 x 10(-6) mol/l) in the superfusion caused a concomitant decrease of angiotensin II/III and aldosterone secretion by 3 normal tissues, and no change in 2 aldosteronomas. These data provide evidence that the human adrenal gland in vitro generates and releases both renin and angiotensin II/III, and support the hypothesis that locally formed angiotensin II/III may play a role as a paracrine regulator of physiological aldosterone secretion.

Adenoma↗
PubMed1990

Pro-gamma-MSH levels in various disorders of pituitary-adrenal axis.

N-Terminal (1-76) portion of proopiomelanocortin (hNT) was measured in normals, Addison's, Nelson's, Cushing's disease, and in dexamethasone suppressible hyperaldosteronism (DSH) by using a specific homologous RIA. Mean basal immunoreactive hNT level was 94.2 +/- 6 pg/ml (mean +/- SE) in normal subjects. In Cushing's disease hNT values were slightly but not significantly (121 +/- 26.5 pg/ml) higher. In patients with DSH the levels were within normal range while they were much higher in Addison's and Nelson's syndromes. A strong correlation was found between IR-hNT and ACTH in plasma of normal subjects and patients with different disorders of the pituitary-adrenal axis (r = 0.83, p less than 0.01). Corticotropin-Releasing-Hormone (CRH) test in Cushing's disease stimulated the release of both ACTH and IR-hNT, showing a slightly different pattern of secretion. Similar patterns of secretion were found for hNT and ACTH in various pituitary-adrenal abnormalities. Normal levels of hNT in DSH do not support a role of this peptide in the pathogenesis of the disorder. Measurement of hNT in plasma can provide an additional tool for the diagnosis of patients with various disorders of the hypothalamic-pituitary-adrenal axis.

Addison Disease↗
PubMed1990

Low-dose ketoconazole treatment in hirsute women.

Ketoconazole is an orally active antimycotic agent and a potent inhibitor of gonadal and adrenal steroidogenesis. As inhibitor of steroid production, it has been employed in Cushing's syndrome, prostatic cancer and precocious puberty due to autonomous Leydig-cell hyperfunction. By virtue of its selective action on androgen synthesis at low doses by inhibition of C17-20 lyase, this drug could be of potential therapeutic utility in hirsutism. We evaluated the hormonal and clinical effects of a low-dose regimen (400 mg/day) for 3 months in 16 women with a spectrum of disorders from idiopathic hirsutism to polycystic ovary syndrome. Four of them completed 6-month treatment. At 3 months, DHEA-S decreased from 9.9 +/- 1.0 (mean +/- SE) to 6.9 +/- 1.0 mumol/L (p less than 0.01), androstenedione from 13.3 +/- 1.5 to 8.3 +/- 1.3 nmol/L (p less than 0.005), and testosterone from 4.2 +/- 0.4 to 3.1 +/- 0.4 nmol/L (p less than 0.05). No significant changes were observed in LH, FSH, prolactin and estradiol levels. In patients treated for 6 months, androgens were within normal limits at the end of the study. Eleven out of 16 women (about 70%) reported some improvement in their hirsutism. There was a significant decrease in Ferriman-Gallwey's score (p less than 0.001) and mean hair-shaft diameter (p less than 0.001). The patients treated for 6 months showed a further improvement. Pelvic ultrasonography, when repeated (n = 8), was either unchanged or improved. Side effects (polymenorrhea, gastrointestinal reaction, somnolence) were generally mild and transient. Of 20 women who entered the study the dropout rate was 20% (n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Atrial natriuretic peptide in Cushing's disease.

Atrial Natriuretic Peptide (ANF), is secreted by atrial myocytes in response to atrial stretch. Its plasma levels have been found elevated in conditions leading to salt and fluid repletion and consequent atrial distention. Recently, it has been demonstrated that dexamethasone can enhance ANF secretion, by acting on ANF gene expression and mRNA synthesis. High plasma levels of ANF have been observed in normal man after administration of cortisol and ACTH. In the case of glucocorticoid excess, as in Cushing's disease, limited and conflicting data are available. Therefore, we measured ANF basal values and ANF response to postural changes and volume expansion in eight patients with Cushing's disease. In our patients ANF values were higher than normals. ANF responded to volume expansion, 47.8 +/- 5.1 pg/ml before sodium load and 69.9 +/- 7.0 pg/ml after sodium load, and changed minimally after postural manoeuvres, 47.3 +/- 3.2 pg/ml supine and 41.7 +/- 5.1 pg/ml upright. These data indicate that ANF secretion is enhanced in Cushing's disease, and its regulation is partially altered. Since in this condition hypervolemia has not been certainly demonstrated, a direct relationship between elevated ANF and glucocorticoid excess could be suggested.

Adult↗
PubMed1990

Atrial natriuretic peptide infusion in primary aldosteronism. Renal, hemodynamic and hormonal effects.

We have previously shown that a bolus injection of alpha-human atrial natriuretic peptide (alpha-h-ANP) (100 micrograms) in patients with primary aldosteronism induces a transient decrease of blood pressure and a marked natriuresis, but no changes in plasma aldosterone levels. Eight additional cases were studied with a different protocol. Alpha-h-ANP was infused at the dose of 50 ng/kg/min over 1 h, after a bolus of 50 micrograms; saline alone was infused as control. Blood pressure, heart rate, plasma aldosterone, plasma renin activity, cortisol, serum and urinary Na and K and urinary volume were measured. A slight fall in blood pressure, without heart rate changes, was obtained within the first 5 min; this lasted throughout the infusion and for 1 h afterwards. Urinary volume and urinary sodium were significantly higher than controls during the first 2 h, while urinary potassium slightly increased only during the first hour. Plasma renin activity remained suppressed. Plasma aldosterone levels were similar throughout the infusion. Cortisol was not significantly different than placebo except that there was a significant rise after stopping ANP. These data confirm the potent natriuretic effect of ANP infusion and the lack of correlation between ANP induced natriuresis and the effect of ANP on aldosterone in patients with primary aldosteronism.

Adult↗
PubMed1990

New aspects of mineralocorticoid hypertension.

Primary aldosteronism is the principal disorder of the zona glomerulosa, and a number of subsets have been identified: unilateral adenoma, bilateral micro- or macronodular hyperplasia (idiopathic aldosteronism), primary hyperplasia, and aldosterone-producing carcinoma, either adrenal or ectopic. The diagnostic criteria for a correct differential diagnosis of these subsets are now quite reliable, and our experience is presented in detail. Unfortunately, the pathogenesis of most of these forms is still poorly recognized and requires further investigation. An extreme sensitivity to angiotensin II is present in patients with idiopathic aldosteronism, and a role of adrenal renin is now being advocated. A peculiar form of hyperaldosteronism is the glucocorticoid-remediable subtype. An unusual sensitivity of aldosterone to ACTH is present in this form. The qualitative biochemical abnormality in this disorder consists of a marked overproduction of products of the cortisol C-18-oxidation pathway, 18-hydroxycortisol and 18-oxocortisol, which are more abundant than aldosterone and 18-hydroxycorticosterone. A family with 3 affected sibs has been studied by our group. In other clinical situations, classical zona fasciculata mineralocorticoids (deoxycorticosterone [DOC], corticosterone, and their 18-hydroxy compounds) are secreted in excess. The hypertensive diseases of this zone are rare DOC-secreting tumors and two forms of congenital adrenal hyperplasia, the 11 beta-hydroxylase and 17 alpha-hydroxylase deficiency syndromes, which are identified by the presence of hypokalemia and suppressed renin activity. DOC is the only mineralocorticoid hormone (MCH) oversecreted in the 11-hydroxylase deficiency syndromes, while all ACTH-dependent MCH levels are very high in the 17-hydroxylase deficiency syndromes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1990

Pathogenesis of the type 2 variant of the syndrome of apparent mineralocorticoid excess.

The syndrome of apparent mineralocorticoid excess, which is not a primary disorder of the adrenal cortex, describes the association of an unexplained hypermineralocorticoid state with a decreased rate of peripheral 11 beta-hydroxydehydrogenation of cortisol to cortisone. Studies in this syndrome have led to the hypothesis that peripheral cortisol inactivation is the normal mechanism permitting specific mineralocorticoid recognition. This view reconciled developing evidence that the mineralocorticoid receptor itself could not distinguish between mineralocorticoids and glucocorticoids. The syndrome occurs in two forms. In both forms there is decreased turnover of a normal level of plasma cortisol, consistent with the view that delayed removal of the glucocorticoid from strategic receptor sites unmasks its potential mineralocorticoid agonism. In the type 1 variant, impaired 11 beta-hydroxydehydrogenation is reflected by an elevated cortisol/cortisone metabolite ratio. In three patients with the type 2 variant, this ratio was normal, suggesting that the rate of 11 beta-hydroxydehydrogenation was unimpaired. The hypertension and hypokalemic alkalosis of both forms are improved by spironolactone, but patients with the type 2 variant have responded somewhat better to the suppression of cortisol by dexamethasone.

Adult↗
PubMed1990

Defective fasciculata zone function as the mechanism of glucocorticoid-remediable aldosteronism.

Glucocorticoid-remediable aldosteronism is characterized by unusual sensitivity of aldosterone secretion to ACTH. Suppressibility by glucocorticoid and continued stimulability by exogenous ACTH has provided the basis for diagnosis and treatment of the disorder. A qualitative biochemical abnormality consisting of marked overproduction of the products of the cortisol C-18 oxidation pathway, 18-hydroxycortisol and 18-oxocortisol, has been examined in 10 patients with the disorder and compared to the normal C-18 oxidation products of corticosterone, aldosterone, and 18-hydroxycorticosterone. The technique, based on stable isotope dilution mass fragmentography, measured the tetrahydro urinary metabolites of aldosterone, 18-hydroxycorticosterone, and 18-oxocortisol and unmetabolized 18-hydroxycortisol. All 4 C-18 oxygenated corticosteroids were markedly elevated in the untreated state and showed rapid parallel suppression with low doses of glucocorticoid. The proportional changes in C-18 oxygenated cortisols together with aldosterone and 18-hydroxycorticosterone suggested the mechanism of a common catalytic site of a cytochrome P450 methyl oxidase serving both cortisol and corticosterone substrates. The ACTH-dependent secretion of the C-18 oxidation products of both corticosterone and cortisol in the disorder is attributed to the acquisition of methyl oxidase activity by the fasciculata zone, where there are abundant pools of these precursors.

Adolescent↗
PubMed1990

Role of insulin and atrial natriuretic peptide in sodium retention in insulin-treated IDDM patients during isotonic volume expansion.

Because insulin shows an antinatriuretic effect in healthy humans, insulin therapy resulting in circulating hyperinsulinemia may lead to sodium retention and in turn to hypertension in individuals with insulin-dependent diabetes mellitus (IDDM). Moreover, it has been proved that atrial natriuretic peptide (ANP) plays a major role in modulating natriuresis in humans. This study investigated the relationship between insulin and ANP in modulating sodium metabolism in normotensive and hypertensive IDDM subjects compared with control groups of normotensive and hypertensive nondiabetic subjects. IDDM normotensive and hypertensive subjects had mean +/- SE duration of IDDM of 7 +/- 2 and 8 +/- 2 yr, respectively, and had no clinical features of diabetic nephropathy. All subjects received a saline infusion (2 mmol.kg-1.90 min-1) during euglycemia. IDDM normotensive and hypertensive subjects received a subcutaneous insulin infusion (15 mU.kg-1.h-1), resulting in twofold higher plasma free-insulin levels (16 +/- 2 and 19 +/- 3 microU/ml, respectively) than in nondiabetic normotensive and hypertensive subjects (7 +/- 2 and 8 +/- 2 microU/ml, respectively). During saline challenge, sodium excretion increased by 22 +/- 4% in normotensive and 49 +/- 9% in hypertensive nondiabetic subjects but by only 11 +/- 0.4% in normotensive (P less than 0.01) and 8 +/- 2% in hypertensive (P less than 0.01) IDDM subjects. The impaired natriuretic response to saline challenge was mainly due to greater rates of sodium reabsorption by kidney proximal tubules in IDDM than nondiabetic subjects. At baseline, plasma ANP concentrations were significantly higher in both IDDM groups than in control groups (normotensive IDDM and control subjects: 38 +/- 4 and 19 +/- 2 pg/ml, respectively, P less than 0.01; hypertensive IDDM and control subjects: 45 +/- 6 and 27 +/- 4 pg/ml, respectively, P less than 0.05). After saline challenge, ANP concentrations rose to 39 +/- 4 pg/ml in normotensive and 49 +/- 5 pg/ml in hypertensive control subjects, whereas no significant change above baseline value was seen in IDDM subjects. Both IDDM groups showed a 10-12% greater exchangeable Na+ pool than control subjects regardless of the presence of hypertension. Subcutaneous insulin infusion, resulting in circulating plasma free-insulin levels in normotensive control subjects comparable to those in IDDM patients, inhibited natriuresis, increased proximal tubule sodium reabsorption at the level of the kidney, and inhibited an adequate ANP stimulation by saline challenge. We conclude that hyperinsulinemia leads to increased proximal tubule sodium reabsorption and impaired ANP response during saline administration. Both mechanisms account for sodium retention in normotensive and hypertensive IDDM patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Lack of aldosterone inhibition by atrial natriuretic factor in primary aldosteronism: in vitro studies.

Several studies demonstrated that aldosterone secretion, by bovine, rat and human glomerulosa cells, is inhibited in vitro by atrial natriuretic factor (ANF). This effect has also been investigated with conflicting results in cells taken from aldosterone-producing tumors. In the present study, atrial natriuretic factor has been tested on aldosteronoma cells obtained from 4 patients with primary aldosteronism. The cells were studied both with perfusion and incubation systems. Aldosterone secretion was stimulated by ACTH, angiotensin II and potassium with or without ANF 10 microM. In this study ANF lacked to inhibit either basal and stimulated aldosterone secretion, indicating some alterations of ANF-adrenal interaction in this syndrome.

Adenoma↗
PubMed1989

The pathogenesis of pseudohyperaldosteronism from carbenoxolone.

Carbenoxolone is a derivative of glycyrrhetinic acid used for the treatment of peptic ulcer and gastritis, with salt and water retention a very common side-effect. To investigate this drug-induced pseudohyperaldosteronism we have studied 6 male volunteers before, during and after treatment with carbenoxolone for 7 days. Serum, urinary and sweat electrolytes values were consistent with a mineralocorticoid-like effect of drug administration. PRA was suppressed, and plasma cortisol and aldosterone progressively decreased over treatment. We have also determined by radioreceptor assay the plasma levels of factors which bind to mineralocorticoid receptors in rat kidney cytosol. The levels of these factors were decreased significantly at day 3 of treatment, suggesting a local renal effect of carbenoxolone to amplify endogenous steroid action. At day 7 the radioreceptor assay values were still decreased but significantly higher than at day 3, suggesting in addition a direct mineralocorticoid effect of the drug. We conclude that the drug is initially effective by amplifying the effect of endogenous steroids, and then when the plasma concentrations of the drug or its metabolites reach a higher plasma concentration, there may also be in addition a direct mineralocorticoid-like effect.

Adult↗
PubMed1989

A new form of the syndrome of apparent mineralocorticoid excess.

The syndrome of apparent mineralocorticoid excess combines the features of unexplained but spironolactone-correctable mineralocorticoid excess in association with a decreased rate of oxidation of cortisol to cortisone. No relationship was initially implied between the pathogenesis of the disorder and the metabolic disturbance as expressed by an elevated cortisol:cortisone metabolite ratio but the ratio itself has served as a biochemical marker for the disorder. Cortisol has been suggested as the mineralocorticoid in a setting of enhanced sensitivity to the steroid as a result of the incomplete oxidative metabolism of cortisol by the kidney. We present evidence that diminished conversion of cortisol to cortisone is not an obligatory mechanism in the syndrome of apparent mineralocorticoid excess. A form of the disorder is described, designated the Type 2 variant, in which all features are preserved except that the cortisol:cortisone metabolite ratio is normal. An essential feature of both variants, however, is a decrease in the cortisol metabolic clearance rate. These findings require a more generalized definition of the syndrome of apparent mineralocorticoid excess to include other deficient mechanisms of metabolic inactivation of cortisol.

Adolescent↗
PubMed1989

Aldosterone and pressor responses to angiotensin II in primary hyperparathyroidism.

The aim of this study was to assess the effect of hypercalcaemia due to primary hyperparathyroidism on the pressor and aldosterone responses to angiotensin II (Ang II) infusion. Five patients with hyperparathyroidism were studied, before and after parathyroidectomy, and were compared with five normal subjects. After 30 min of equilibration, Asp1-Val5 Ang II was infused in all subjects at stepwise increasing dose rates of 2 and 4 ng/kg per min for 30 min each. In the hyperparathyroid patients the baseline levels of plasma parathyroid hormone and calcium were significantly higher than in the controls, and returned to normal after the parathyroidectomy; plasma aldosterone and renin activity were normal both before and after the parathyroidectomy. Two hyperparathyroid patients had high blood pressure levels, which were normalized after surgery. The increase in the aldosterone response from baseline at each time point of the Ang II infusion was greater in the hyperparathyroid patients before than after the operation (P less than 0.05), and greater than in the normals (P less than 0.05). No difference in the increased response of systolic or diastolic blood pressure was observed between the hyperparathyroid patients, either before or after the parathyroidectomy, and the normal subjects. High levels of extracellular calcium or parathyroid hormone, or both, might play a primary role in the aldosterone hyper-responsiveness to Ang II in the hyperparathyroid patients. The similar pressor response to Ang II in hyperparathyroid patients and the normal subjects suggests that hypercalcaemia does not potentiate the vasoconstrictive action of Ang II.

Adult↗
PubMed1989

Atrial natriuretic factor in hypertensive and normotensive insulin-dependent diabetics.

Since insulin increases renal sodium reabsorption, hyperinsulinaemia in insulin-treated insulin-dependent diabetes mellitus might lead to sodium retention and, in turn, increase atrial natriuretic factor (ANF) values. We investigated ANF levels in insulin-dependent diabetes mellitus with and without hypertension. We infused saline (2 mmol/kg per 90 min) in nine normotensive controls, eight normotensive diabetics, seven hypertensive controls and six hypertensive diabetics during the imposition of a euglycaemic glucose clamp with an artificial pancreas. Baseline ANF values were higher in the normotensive and hypertensive diabetics than in the normotensive and hypertensive controls. During a sodium load the sodium excretion rate increased significantly in controls but not in the diabetic groups. The ANF pattern was similar, values being significantly increased in controls and unchanged in diabetic patients. We conclude that euglycaemic, slightly hyperinsulinaemic, insulin-dependent diabetes mellitus patients with and without hypertension are characterized by higher baseline ANF values and an impaired response to an acute saline load as shown by the sodium excretion rate and the plasma ANF concentration.

Atrial Natriuretic Factor↗