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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The conditions which must be respected to ensure the validity of the biochemical diagnostic criteria of primary hyperaldosteronism, conditions of blood sampling, timing posture and age of the patient, sodium intake and intercurrent drug therapy. As none of the tests is 100 p. 100 specific in distinguishing adrenal adenoma from hyperplasia, an association of several investigations has to be used. In cases of adenoma, the authors recommend the investigations which demonstrate the autonomy of secretion and the prevalence of circadian rhythm over the influence of change in posture. The measurement of aldosterone levels may be completed by that of its precursor, 18-hydroxy-corticosterone (18 OH CS).
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PMID:[Aldosterone in primary hyperaldosteronism]. 662 15

The effects of the antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), ethoxyquin (EQ), and sodium L-ascorbate (SA) on two stage chemical carcinogenesis were investigated in male F344 rats initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-ethyl-N-hydroxyethylnitrosamine (EHEN), N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) or N-methylnitrosourea (MNU). BHA was given in diet at a dose level of 0.5 or 2.0%, BHT at 1.0%, SA at 5.0% and EQ at 0.8% for 29-51 weeks. Complete autopsy was performed at sacrifice and organs were examined histologically for the presence of preneoplastic and neoplastic lesions. All of the antioxidants tested exerted a positive influence on the development of BBN- or MNU-initiated bladder carcinogenesis. Similarly, these chemicals tended to enhance the appearance of forestomach tumors although the data gained after BHT administration were not significant. In clear contrast, no effect was observed on glandular stomach carcinogenesis and, with the exception of SA, the antioxidants all showed inhibition of the development of preneoplastic and neoplastic lesions in the liver. EQ increased the occurrence of renal adenoma in EHEN-treated rats. Clear differences were observed with respect to the modification of thyroid carcinogenesis after MNU initiation, BHT demonstrating strong promotion activity whereas BHA and SA had no effect. Thus organ specificity, with regard to both direction of modification and to the effects of individual antioxidants was apparent, this intriguing finding offering hope for the development of future experimental approaches for elucidation of the mechanisms underlying chemical carcinogenesis.
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PMID:Modification of chemical carcinogenesis by antioxidants. 668 Jul 29

Thirty-four patients with untreated Conn's syndrome were studied in a metabolic ward. The final diagnosis in each case was based on the finding and removal of an adrenal cortical adenoma with histological features typical of the disorder. Compared with 34 age and sex-matched normal controls the untreated patients had increased plasma aldosterone concentration, increased blood pressure (183/112 mmHg), increased exchangeable sodium (116.7% of normal), hypokalaemia and increased plasma sodium concentration. Exchangeable potassium was lower than normal and plasma concentrations of active renin, total renin and angiotensin II were lower than normal mean values. Arterial pressure correlated significantly and positively with plasma and exchangeable sodium and there was a significant negative correlation with plasma potassium concentration. Partial regression analysis showed that the relation of exchangeable sodium with blood pressure did not depend on age or renal function but that the relation of blood pressure and plasma potassium could be attributed to the correlation of exchangeable sodium and blood pressure. Multiple regression analysis suggested that exchangeable and plasma sodium were the most important determinants of blood pressure in untreated patients. Spironolactone, amiloride and surgical removal of the adenoma corrected the electrolyte abnormality and usually lowered blood pressure. The fall in exchangeable sodium was related to the fall in blood pressure. The pattern of correlation found by multiple regression analysis in postoperative patients was similar to that in normal subjects. The findings are relevant to some of the mechanisms proposed for the hypertension of mineralocorticoid excess.
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PMID:Relation of blood pressure with body and plasma electrolytes in Conn's syndrome. 668 Oct 39

A 46-year-old woman with hypertension, normokalemia, suppressed renin, normal catecholamines, and a left adrenal mass on the CT scan was found to have excessive 18-hydroxycorticosterone (18-OHB) and normal aldosterone levels in plasma, both of which responded poorly to sodium restriction and angiotension II, and supranormally to ACTH. Plasma 18-hydroxydeoxycorticosterone (18-OHDOC) was normal. After adrenalectomy, amelioration from hypertension occurred with a reduction in plasma 18-OHB and aldosterone. The plasma 18-OHDOC remained normal. The adrenal tumor was histologically an adenoma, containing a large amount of 18-OHB and a small amount of aldosterone. Thus, the present adenoma seems to be a variant of aldosteronomas.
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PMID:Adrenal adenoma with 18-hydroxycorticosterone excess and hypertension: a variant of aldosteronomas. 674 43

Little is known regarding the response of the renin-angiotensin-aldosterone system to dynamic maneuvers after surgical removal of an aldosterone-producing adenoma or whether normal renin-aldosterone relationships are restored following surgery. We utilized maneuvers designed to assess the adequacy of aldosterone suppression and renin stimulation to rapid changes in sodium and fluid volume status to examine these relationships in 21 patients before and after surgery for primary aldosteronism. All patients failed to suppress plasma aldosterone normally after intravenous saline infusion and failed to stimulate renin activity into the normal range following diuretic-induced sodium and volume depletion. No relationship between renin and aldosterone was discerned. The studies were repeated 6 mo. to 4 yrs. after unilateral adrenalectomy in all 21 patients. In every case the normal suppression of aldosterone and stimulation of renin was observed. Moreover a significant (p less than 0.001) relationship between renin and aldosterone was demonstrable. Thus in this population of patients with surgically responsive primary aldosteronism, no abnormality of aldosterone production persisted.
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PMID:Restoration of renin-aldosterone dynamics to normal following surgery in primary aldosteronism. 675 50

Hemodynamic mechanisms underlying the hypertensive action of long-standing sodium overload were studied in ten subjects with aldosterone-producing adenoma. Arterial pressure was 129+/-4/91+/-4 mm Hg (mean+/-SEM) during spironolactone treatment, 177+/-5/114+/-3 mm Hg six weeks after the drug had been stopped, and 136+/-4/94+/-3 mm Hg two months after operation. In the six weeks following cessation of spironolactone, cardiac output, stroke volume, blood volume and sodium space were determined at weekly intervals. In each subject the biochemical syndrome of aldosterone-excess had been fully developed in two weeks. The hemodynamic changes in that period were also uniform. Mean arterial pressure in week 2 was increased by 20+/-3% with parallel increments of cardiac output and stroke volume of 22+/-5 and 30+/-6%. Blood volume and sodium space were increased by 11+/-2 and 29+/-4%. The patterns in weeks 2-6 were not uniform. In five subjects (age 33-49 yr) the hypertension was maintained through increased cardiac output; in week 6 it was 34+/-7% above its initial value, and stroke volume and blood volume were 37+/-4 and 16+/-4% above control. In the remaining five subjects (age 50-60 yr) cardiac output, stroke volume and blood volume returned to their initial values, and total peripheral resistance in week 6 was 36+/-13% above control. Sodium space remained expanded in both groups. The measurements after surgery confirmed the existence of the high-flow and high-resistance patterns; there was a decrease in cardiac output in the former group of subjects and a decrease in resistance in the latter. Apparently, increased resistance is not a direct consequence of increased flow. The observed age-related differences in hemodynamic patterns of sodium overload bear some resemblance to essential hypertension where a high-flow state of long duration may precede the ultimate phase of low vascular capacitance and high resistance.
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PMID:Recurrence of hypertension in primary aldosteronism after discontinuation of spironolactone. Time course of changes in cardiac output and body fluid volumes. 675 51

The electrophysiological properties of tumoral pituitary cells were studied in 4 types of human adenomas including prolactinomas, growth-hormone-secreting tumors, adrenocorticotropin-hormone-secreting adenoma and 'non-functioning' tumors. Only 9% of the cells from prolactinomas and ACTH tumors were excitable but they never elicited spontaneous action potentials. These cells did not respond to substances known to act on the hormone-releasing process (thyreoliberin, dopamine). However, 37% of the cells cultured from growth-hormone-secreting adenomas and from 'non-functioning' tumors displayed action potentials. The action potential was calcium-dependent, i.e., it was blocked by cobalt, nickel and methoxyverapamil and could be recorded in a sodium-free medium. Thyreoliberin triggered action potentials, whereas dopamine and gamma-aminobutyric acid inhibited electrical activity. These results show that human tumoral pituitary cells in culture are able to generate Ca2+-dependent action potentials. The data from growth-hormone-secreting tumors are in good agreement with the stimulus-secretion coupling concept; however, differences in the response of cells cultured from other types of human pituitary tumors suggest that each type of adenoma has specialized membrane properties.
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PMID:An electrophysiological study of cultured human pituitary cells. 681 48

Tumor-promoting effects of phenobarbital (PB) and sodium saccharin (SS) were tested in rats pretreated with N-nitrosomethylurea (NMU) with special reference to the site of their action. Male F344 rats were initially given injections of NMU (20 mg/kg i.p.) twice a week for 4 weeks, then given basal diet containing 0.05% PB or 5% SS for the next 32 weeks, and then killed. Appropriate control studies were also done. Histological examination of whole organs of the rats showed that PB promoted thyroid carcinogenesis whereas SS did not. A significant increase in the incidences of total tumors as well as papillary adenocarcinoma of the thyroid was observed in the group given PB after NMU (p less than 0.001). The incidence of papillary adenoma with or without papillary adenocarcinomas was also high in the NMU-PB-treated group. The organ-specific promoting effect of PB in the induction of preneoplastic lesions, as demonstrated by development of gamma-glutamyl transpeptidase-positive foci in the liver and of SS in papillary or nodular hyperplasia in the urinary bladder, as reported previously, was also confirmed. The incidences of papillomas in the forestomach were similar in groups treated with NMU-PB, NMU-SS, or NMU alone. The results indicate that PB is a tumor promoter in the liver and thyroid and that SS is a tumor promoter in the urinary bladder of rats.
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PMID:Organ-specific promoting effect of phenobarbital and saccharin in induction of thyroid, liver, and urinary bladder tumors in rats after initiation with N-nitrosomethylurea. 685 Jun 38

We report a case of primary hyperaldosteronism in a 37-year-old woman presenting early in pregnancy with hypertension and hypokalaemia. Plasma renin concentration was suppressed and unaffected by sodium restriction or upright posture at 16 and 35 weeks gestation, or seven days post-partum. Recumbent plasma aldosterone was elevated, and normal postural response lost both at 35 weeks gestation and seven days post-partum. Vaginal delivery, following induction at 38 weeks, was uncomplicated. Two months postpartum C.T. scan and adrenal venous catheterisation studies indicated a left sided adenoma and left adrenalectomy was performed. Within seven days the patient was normotensive with normal serum potassium and urinary aldosterone on no treatment.
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PMID:Primary hyperaldosteronism in pregnancy. 696 Aug 78

Hypertension and hypokalemia were found in a 60-yr-old woman suffering from primary hyperparathyroidism. Laboratory investigations in this patient disclosed 1) elevated levels of plasma aldosterone (PA) which could not be suppressed by a high sodium diet alone or in combination with fludrocortisone (Florinef); 2) a decline of the elevated PA levels after 4 h of ambulation; and 3) low PRA which was unresponsive to stimulation by a low sodium diet coupled with diuretic-induced volume depletion and 4 h of ambulation. These findings were consistent with the diagnosis of primary hyperaldosteronism. Extirpation of a parathyroid adenoma reduced the patient's serum calcium level to normal, and subsequently, a normalization of her blood pressure, serum electrolytes, PA, and PRA were observed. On the basis of these data is is suggested that in this case hyperaldosteronism may have been caused directly or indirectly by primary hyperparathyroidism.
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PMID:Primary hyperparathyroidism: possible cause of primary hyperaldosteronism in a 60-year-old woman. 699 17


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