Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypertension and cardiomyopathy are prominent findings in humans and rats harboring pheochromocytomas, tumors that can secrete enormous quantities of catecholamines. We have previously found that alpha- and beta-adrenergic receptor antagonists may ameliorate the hypertension and cardiomyopathy found in New England Deaconess Hospital rats implanted with pheochromocytoma. The present studies were designed to determine the possible action of the angiotensin converting enzyme inhibitor captopril on these changes in rats harboring pheochromocytomas. Rats were implanted with transplantable pheochromocytomas and treated with captopril dissolved in the drinking water (1 mg/ml) for 4-6 weeks. Systolic blood pressure was monitored by using the tail-cuff technique. In the rats with pheochromocytoma, blood pressure progressively increased to 184 +/- 3 mm Hg after the tumor was implanted. However, in rats with pheochromocytoma treated with captopril in the drinking water before the development of hypertension, blood pressure did not increase (137 +/- 3 mm Hg). In rats with pheochromocytoma with established hypertension, captopril normalized the systolic blood pressure. Plasma norepinephrine was markedly elevated to a similar extent in both groups compared with unimplanted control rats. Plasma renin activities were slightly lower in rats with pheochromocytoma compared with unimplanted control rats. Treatment with captopril of rats with pheochromocytoma did not modify contraction of isolated rings of thoracic aorta exposed in vitro to either phenylephrine or angiotensin II. Treatment with captopril markedly attenuated the cardiomyopathy induced by pheochromocytoma. These results demonstrate that captopril prevents the development of hypertension despite markedly elevated concentrations of catecholamines. In addition, captopril attenuates catecholamine-induced cardiomyopathy in pheochromocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Captopril improves hypertension and cardiomyopathy in rats with pheochromocytoma. 215 6

A renin promoter-large tumor antigen (T antigen) fusion gene was constructed to provide a reporter function for renin expression in transgenic mice. These transgenic mice gave rise to tumors in subcutaneous soft tissue, which was attributed to transgene expression at this site. An immunohistochemical analysis of transgenic fetuses from several independent lines revealed scattered T-antigen-containing mesenchymal cells and fibroblasts in the subcutaneous layer of the skin between the panniculus carnosus muscle of the skin and the skeletal muscle of the body wall. This localization is consistent with the location of overt tumorigenesis in adult mice. This pattern was specific for the renin-T antigen fusion gene as no immunohistochemical staining was observed in transgenic fetuses containing a heterologous promoter-T antigen fusion gene. Northern blot analysis of tumor RNA indicated that most of the tumors expressed both T antigen and the endogenous renin gene Ren-1c. In addition, when multiple renin genes were introduced by crossing transgenic mice with nontransgenic DBA/2J mice, which contain another allele of the Ren-1 locus as well as the duplicated locus Ren-2, the resultant tumors expressed the Ren-2 gene. Northern blots were then used to analyze renin expression in the subcutaneous tissue of normal mice. Fully processed renin mRNA was detected in eviscerated 15.5-day postcoitus fetal and newborn carcasses and in newborn skin. Our data indicate that there is a renin-expressing cell population in fetal and newborn subcutaneous tissue.
 ...
PMID:Expression of murine renin genes in subcutaneous connective tissue. 217 70

We constructed transgenic mice containing a renin-promoter SV40 T antigen fusion transgene with the intention of inducing neoplasia in renin-expressing cells and isolating renin-expressing cell lines in vitro. We examined six kidney tumors from mice representing three different transgenic lines and found they expressed their endogenous renin gene. Initially, five nonclonal kidney tumor-derived cell lines were established which expressed their endogenous renin gene in addition to the transgene. They retained active renin intracellularly and constitutively secreted an inactive form of renin (prorenin). One of these cell lines was cloned to homogeneity. This line maintained high level expression of renin mRNA throughout 3 months of continuous culture. Although the cells contained an equal proportion of active and inactive renin, the species constitutively secreted into the media was predominantly (95%) prorenin. However, active renin secretion was stimulated 2.3- and 4.6-fold by treatment with 8-bromo-cAMP after 4 and 15 h, respectively. In addition, the presence of multiple secretory granules was confirmed by ultrastructural analysis. These cells, which express renin mRNA and can regulate secretion of active renin, should provide an excellent tool for studying renin gene regulation and secretion. Furthermore, these mice should provide a useful source for the establishment of renin-expressing cell lines from a variety of renin-expressing tissues.
 ...
PMID:Isolation and characterization of renin-expressing cell lines from transgenic mice containing a renin-promoter viral oncogene fusion construct. 217 57

Adenomas of the adrenal cortex which produce aldosterone (APA) are among the surgically correctible causes of hypertension accounting for 0.5 to 1.0% of all hypertensive etiologies. The adenomas have a 5:1 predilection for women and generally present with hypertension or profound hypokalemia. A low plasma renin activity completes the triad for primary hyperaldosteronism which could be caused by adrenocortical cancer, a neoplasm with an average diameter of 12 cm, or idiopathic hyperaldosteronism (IHA), a bilateral hyperplasia of the zona glomerulosa of the adrenal cortex which responds poorly to surgical resection. The adenomas are small (2 cm) but can be localized by imaging or selective venous sampling. Resection has a high success rate with minimal morbidity.
 ...
PMID:Aldosterone-producing tumors (Conn's syndrome). 218 43

Autoregulation of blood flow denotes the intrinsic ability of an organ or a vascular bed to maintain a constant perfusion in the face of blood pressure changes. Alternatively, autoregulation can be defined in terms of vascular resistance changes or simply arteriolar caliber changes as blood pressure or perfusion pressure varies. While known in almost any vascular bed, autoregulation and its disturbance by disease has attracted particular attention in the cerebrovascular field. The basic mechanism of autoregulation of cerebral blood flow (CBF) is controversial. Most likely, the autoregulatory vessel caliber changes are mediated by an interplay between myogenic and metabolic mechanisms. Influence of perivascular nerves and most recently the vascular endothelium has also been the subject of intense investigation. CBF autoregulation typically operates between mean blood pressures of the order of 60 and 150 mm Hg. These limits are not entirely fixed but can be modulated by sympathetic nervous activity, the vascular renin-angiotensin system, and any factor (notably changes in arterial carbon dioxide tension) that decreases or increases CBF. Disease states of the brain may impair or abolish CBF autoregulation. Thus, autoregulation is lost in severe head injury or acute ischemic stroke, leaving surviving brain tissue unprotected against the potentially harmful effect of blood pressure changes. Likewise, autoregulation may be lost in the surroundings of a space-occupying brain lesion, be it a tumor or a hematoma. In many such disease states, autoregulation may be regained by hyperventilatory hypocapnia. Autoregulation may also be impaired in neonatal brain asphyxia and infections of the central nervous system, but appears to be intact in spreading depression and migraine, despite impairment of chemical and metabolic control of CBF. In chronic hypertension, the limits of autoregulation are shifted toward high blood pressure. Acute hypertensive encephalopathy, on the other hand, is thought to be due to autoregulatory failure at very high pressure. In long-term diabetes mellitus there may be chronic impairment of CBF autoregulation, probably due to diabetic microangiopathy.
 ...
PMID:Cerebral autoregulation. 220 48

The pathogenetic relationship between tumor and hypertension was investigated in 40 patients with renal cell carcinoma. 15 of 40 patients were hypertensive. Four of these 15 patients with renal tumors and hypertension (26.7%) were found to have primary reninism. In these patients the plasma renin activity in blood from the renal veins showed a tumor kidney to contralateral kidney ratio of between 6 and 7. In the same 4 cases the renin content in the renal tumor tissue was significantly higher than that in tissue from the adjacent tumor-free renal cortex of the ipsilateral kidney. Immunocytochemical demonstration of renin in the tumor was only possible in these 4 cases. In 3 of these patients blood pressure returned to normal following nephrectomy; in the 4th case there was a drop in blood pressure after nephrectomy. Renin-producing renal cell carcinomas are an uncommon cause of renal hypertension. The differential diagnosis of hypertension should therefore also include renal tumor.
 ...
PMID:Renin-producing renal cell carcinoma. 220 1

The case of a 39-year-old woman with Cushing's syndrome, hypertension and severe hypokalemia, caused by a unilateral adrenal adenoma composed of cells of the zona fasciculata histological type, is described. Plasma renin activity, plasma levels of mineralocorticoids and the aldosterone secretion rate were determined before and after surgical removal of the adenoma. The tumor appeared to produce autonomously cortisol as well as corticosterone, 18-hydroxycorticosterone and aldosterone. This condition has not previously been described in the literature and might be explained by strong expression of the full spectrum of activities of the mitochondrial enzyme P450 C11 by the tumor cells. Interestingly, despite hyperaldosteronism, plasma renin activity was not suppressed.
 ...
PMID:Concurrent hypercortisolism and hyperaldosteronism due to an adrenal adenoma. 223 30

The captopril test was used to make a differential diagnosis of various types of primary aldosteronism. After captopril, there was no change in the activity of the renin-angiotensin-aldosterone system only in the group of patients with aldosterone-producing adenomas in a histological variant of "adenoma and atrophy". The findings suggest that aldosterone secretion regulation is autonomic in the adenoma unassociated with the function of the renin-angiotensin-aldosterone system only in the case of isolated adenoma with a histological variant of adenoma and atrophy. In patients with aldosterone-producing adenomas in the presence of the variant "adenoma and hyperplasia", aldosterone secretion retains sensitivity to the renin-angiotensin-aldosterone system as in patients with idiopathic hyperplasia and hypertensive disease, which indicates that it is possible to differentiate isolated "adenoma and atrophy" from hypertensive disease and idiopathic hyperplasia, despite its combination with tumor by using the captopril test.
 ...
PMID:[Significance of single-dose captopril test in the differential diagnosis of primary aldosteronism]. 229 Feb 81

The adrenal function mainly cortical one, was evaluated in 16 patients with incidentally discovered adrenal masses. Pathological examination was possible in 15 cases. The finding consisted of adrenocortical adenoma in 9, adrenocortical nodular hyperplasia in 1, adrenal medullary hyperplasia in 1, metastatic tumor in 2 and adrenal cyst in 2. Another case of adrenal cyst was diagnosed by percutaneous puncture. In all cases peripheral levels of plasma cortisol, plasma aldosterone concentration and plasma renin activity were normal. Plasma catecholamine levels were also normal except in a case of adrenal medullary hyperplasia. On the other hand, the cases of adrenocortical adenoma displayed elevation of urinary 17-hydroxycorticosteroids in 6/9 (67%), a loss of plasma cortisol circadian rhythm in 3/7 (43%) and insufficient suppression on dexamethasone (DXM) suppression test in 6/9 (67%). Their adrenal scintigraphy (with 131I-6 beta-iodomethyl-9-nor-cholest-5 (10)-en-3 beta-ol) revealed an increased ipsilateral up-take and insufficient suppression after DXM in all, while a diminished contralateral up-take in 4/9 (44%). These data suggested that a considerable number of adrenal incidentalomas may not be truly "non-functioning". Two patients with cortical adenoma experienced post operative adrenal insufficiency (25%). It was suggested that a pre-operative loss of plasma cortisol circadian rhythm was the most prognosticating of the post operative adrenal insufficiency, rather than insufficient DXM suppression or scintigraphic absence of contralateral up-take. Among the patients with malignancy, differentiation of incidental adrenal adenoma from metastasis by size alone may not be reliable.
 ...
PMID:[Clinical experience of adrenal incidentaloma with particular reference to adrenal cortical function]. 229 17

A 64-year-old man with sudden onset of quadriplegia due to marked hypokalemia was referred to our clinic with suppressed plasma renin activity in the presence of a low aldosterone level. Computerized tomography demonstrated a left adrenal adenoma, shown on adrenal scintigraphy to be functioning. The elevated basal level of plasma corticosterone and its increased response to 1-24 adrenocorticotropic hormone suggested the tumor produced corticosterone. The surgical specimen was a benign adrenocortical adenoma with excess content of corticosterone and 18-hydroxycorticosterone.
 ...
PMID:Adrenal adenoma with excess secretion of corticosterone and 18-hydroxycorticosterone. 238 39


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>