Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0031511 (pheochromocytoma)
 14,622 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A sensitive and specific reversed-phase liquid-chromatography (HPLC) method for the determination of urinary free and conjugated 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) was developed. Sample preparation is minimal and the method is ideally suited for routine clinical assays of this catecholamine metabolite. Reported in this paper are excretion profiles of controls subjects and patients with pheochromocytoma. Quantitative results were expressed as microgram MHPG per mg creatinine, in order to eliminate variations associated with the 24-h urine collection. The levels of free and conjugated MHPG, determined in 20 control subjects ranged between 0.04--0.11 microgram/mg of creatinine and 0.48--1.25 microgram/mg of creatinine, respectively. The corresponding levels of free and conjugated MHPG in 8 patients with pheochromocytoma were 0.29--1.21 microgram/mg of creatinine and 2.47--15.98 microgram/mg of creatinine, respectively. The described liquid-chromatographic analysis, coupled with the highly sensitive electrochemical detection, provides a simple and reliable method for metabolic profiling of catecholamine by-products at their endogenous levels. This offers an attractive possibility for the detection of neural crest lesions which may cause problems in diagnosis because of their small size, infrequent occurrence and symptoms similar to those of essential hypertension.
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PMID:Endogenous levels of free and conjugated urinary 3-methoxy-4-hydroxyphenylethyleneglycol in control subjects and patients with pheochromocytoma determined by reversed-phase liquid chromatography with electrochemical detection. 738 11

Using randomly voided 1-h urine samples, levels of excretion of catecholamines (CA) and 4-hydroxy-3-methoxymandelic acid (vanillylmandelic acid; VMA) were determined in order to save time in and simplify the diagnostic work-up of pheochromocytoma, particularly in out-patient hypertension clinics. Twenty-nine patients with surgically verified pheochromocytoma (15 paroxysmal and 14 sustained type), 56 patients with essential hypertension (26 labile and 30 fixed type) and 14 normal volunteers were studied. Abnormally high excretion of CA and VMA was found in all patients with pheochromocytoma when compared to those with essential hypertension or to normal controls after duly considering the influence of external factors such as food and exercise. From these results, we concluded that assays of CA and VMA even in random 1-h urine samples are useful in separating patients with pheochromocytoma from those with other types of hypertension.
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PMID:Random one-hour urine catecholamine and 4-hydroxy-3-methoxymandelic acid assays for diagnosis of pheochromocytoma. 739 76

The effects of glucagon on the adrenergic system have been studied in experimental and clinical conditions. 1. in vitro studies: In the first experiment a continuous flow incubation system was developed in which the secretory response to these drugs was characterized by a serial fluorimetric assay of catecholamines in the effluent medium. Pig adrenal medulla or human pheochromocytoma were studied. There was an initial massive release of catecholamines which declined to basal levels (0.02 micrograms/mg) after 1.5 hours. When 10(-4) glucagon was infused for 10 minutes following 2 hours of preincubation, both adrenaline and nonadrenaline outputs rose abruptly to concentrations of 0.08 micrograms/mg and 0.07 micrograms/mg respectively. In the second experiment the effect of these drugs on the in vitro release of catecholamines from the isolated in vitro chromaffin granules of the pig adrenal medulla were studied. The results were the same as in the previous experiment. 2. clinical studies: The effects of glucagon were studied on the blood pressure and urinary catecholamine levels of healthy control subjects, of patients suffering from essential hypertension, thyroid disease, diabetes mellitus and acromegaly. Glucagon induced a slight but constant increase in blood pressure. By contrast no significant urinary catecholaline elevation was evoked. There was no difference in the effect of intravenous glucagon between normal subjects and patients suffering from the above-mentioned disorders.
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PMID:[A reevaluation of the glucagon provocative test for pheochromocytoma--on the in vitro release of catecholamine from the adrenal medulla or pheochromocytoma tissue, and on the effect of intravenous glucagon on urinary catecholamine excretion and blood pressure (author's transl)]. 740 74

Pancreastatin (PST), a 49 amino acid peptide originally isolated from porcine pancreas, is derived from chromogranin A (Cg A), an acidic protein co-released with catecholamines from sympathetic nerve terminals and chromaffin cells. Extracellular processing of Cg A yields PST as well as other biological active peptides. Measurement of Cg A and PST-like immunoreactivity (PST-LI) has been used to investigate patients with pheochromocytoma and other neuroendocrine neoplasia. Some studies have found increased plasma norepinephrine (NE) levels in essential hypertension. We therefore measured venous plasma PST-LI and catecholamines in patients with essential hypertension. We employed a radioimmunoassay developed with commercially available reagents for measuring plasma PST-like immunoreactivity, and HPLC with electrochemical detection for measurement of plasma catecholamines. The correlation of PST-LI with epinephrine (E) was very weak. However, its correlation with NE was highly significant. Thus, venous plasma PST-LI immunoreactivity may reflect sympathetic nerve activity in essential hypertension.
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PMID:Plasma pancreastatin-like immunoreactivity correlates with plasma norepinephrine levels in essential hypertension. 747 67

The results of our study show that parasympathetic tone was higher in patients with pheochromocytoma than in patients with primary hypertension. An unusual spectral form of vagal activity was seen during excessive beta-adrenergic stimulation, while persistent hypertension with an excessive alpha-adrenergic stimulation was responsible for low cardiac sympathetic tone, probably due to desensitization of beta-adrenergic receptors.
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PMID:Heart rate variability in pheochromocytoma. 748 14

Phaeochromocytoma, "perhaps the most fascinating of all tumors" [1], can present with a broad range of clinical manifestations [2]. Once suspected, the biochemical diagnosis is straightforward in most patients since plasma and urinary levels of noradrenaline and/or adrenaline, and urinary metabolites are well above those encountered in healthy subjects or patients with essential hypertension [3,4]. Exceptions to this general rule are well known, however, hence suppression tests have found favour, particularly in cases where catecholamine levels are within, or close to, the normal range [5-7]. We present a unique patient with malignant phaeochromocytoma whose plasma noradrenaline levels were in the high-normal range, and suppressed normally with clonidine administration. He had extremely high circulating levels of dihydroxyphenylalanine (dopa) which were not affected by clonidine, and different patterns of catecholamine concentrations in tumour tissue and plasma.
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PMID:Malignant phaeochromocytoma with high circulating DOPA, and clonidine-suppressible noradrenaline. 749 59

The purpose of this investigation was to assess whether the phentolamine test is able to predict blood pressure fluctuations during operations on patients with pheochromocytoma. We administered 5 mg phentolamine intravenously to 11 patients with pheochromocytoma and 6 patients with essential hypertension, pretreated with alpha-adrenoceptor antagonists. Plasma concentrations of epinephrine and norepinephrine were determined before and after phentolamine administration, and blood pressure was measured repeatedly. Subsequently, all patients with pheochromocytoma underwent adrenal operations. Evidence is presented to show that: (1) in patients with pheochromocytoma whose blood pressure remains stable during their operation, phentolamine produces no clear effects on mean blood pressure (MBP), plasma epinephrine and plasma norepinephrine except in one patient with Sipple's syndrome, (2) in patients with pheochromocytoma exhibiting unstable blood pressure changes during surgery, phentolamine lowers MBP and raises plasma norepinephrine and (3) in patients with essential hypertension, MBP and plasma catecholamines remain unchanged following phentolamine administration. Based on these findings, this pharmacological test appears to be useful for predicting hemodynamic stability in patients with pheochromocytoma pretreated with alpha-adrenoceptor antagonists.
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PMID:Phentolamine test for operative complications of pheochromocytoma: its prognostic importance. 762 32

One hundred and thirty-five patients with malignant hypertension seen over a period of 11 years (1979 to 1989) at a referral hospital were analyzed to characterize the clinical features and etiology of this disease. Ninety male and 45 female patients with an average age of 38.2 +/- 1.4 years were studied. Malignant hypertension was the presenting feature in 68 patients. The etiology included essential hypertension in 88 patients and a secondary cause in 47 patients. Secondary causes included a renovascular etiology in 20 patients, renal parenchymal disease in 19, pheochromocytoma in 6 and Conn's syndrome and adrenal carcinoma in one patient each. Among the 20 patients with renovascular hypertension, Takayasu's arteritis was seen in 15 (75%). The mean age of patients with essential hypertension was 41.7 + 1.14 years while the mean age in patients with secondary hypertension was 33.2 + 1.96 years. Duration of preexisting hypertension was longer in essential hypertensives (2.42 + 0.45 years) than in patients with secondary hypertension (1.27 + 0.41 years, p < 0.05). Raised serum creatinine was seen in 93 patients. Seventy-seven patients had left ventricular hypertrophy on ECG. Ninety-six patients were followed for a period ranging from 18 months to 10 years (mean 32 months). Sixteen patients died during hospital stay while 6 patients died during the follow-up period. The deaths were related to the effects of uncontrolled hypertension including, renal failure (11), stroke (6), congestive cardiac failure (3) and myocardial infarction (1).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Malignant hypertension in north west India. A hospital based study. 783 Mar 25

To elucidate whether a difference in blood pressure reactivity exists between patients with pheochromocytoma (n = 8) and pseudopheochromocytoma (n = 22), we evaluated blood pressure changes during a Valsalva maneuver and baroreceptor reflex sensitivity. We also examined the effects of propranolol and prazosin on blood pressure reactivity during a Valsalva maneuver in patients with pseudopheochromocytoma. Pseudopheochromocytoma was defined as a paroxysmal rise in blood pressure accompanying pheochromocytoma-like symptoms and normal catecholamine values. The difference in systolic blood pressure between phase IV of the Valsalva maneuver and baseline (delta SBP) was markedly smaller in the pheochromocytoma patients (8.4 +/- 18.4 mm Hg) than in the essential hypertension patients (n = 30, 30.9 +/- 19.4 mm Hg) and normotensive control subjects (n = 10, 31.3 +/- 11.4 mm Hg), whereas delta SBP in the pseudopheochromocytoma patients (77.8 +/- 11.2 mm Hg) was markedly greater than in the other three groups. delta SBP was markedly suppressed by the administration of both propranolol and prazosin. Baroreceptor reflex sensitivity index was lower in the pheochromocytoma group than in the other three groups. In conclusion, blood pressure reactivity responses to a Valsalva maneuver are disparate between pheochromocytoma and pseudopheochromocytoma. The high blood pressure reactivity to a Valsalva maneuver in pseudopheochromocytoma is due to hyperactivity in both beta- and alpha 1-adrenergic receptor functions, and the low blood pressure reactivity to a Valsalva maneuver in pheochromocytoma seems to be mainly due to the desensitization of both adrenergic systems associated with chronic catecholamine excess. In addition, the impaired baroreceptor function in pheochromocytoma is partially responsible for it.
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PMID:Blood pressure response to the Valsalva maneuver in pheochromocytoma and pseudopheochromocytoma. 784 77

Adrenomedullin is a potent hypotensive peptide newly discovered in pheochromocytoma tissue by monitoring its elevating activity on platelet cAMP. We measured plasma concentration of adrenomedullin in patients with essential hypertension and chronic renal failure. As compared with normal subjects, plasma adrenomedullin was increased by 26% (P < 0.05) in hypertensives without organ damage and by 45% (P < 0.005) in those with organ damage. The increase in plasma adrenomedullin was more prominent in renal failure than in hypertension. Renal failure patients with plasma creatinine of 1.5-3, 3-6, and > 6 mg/dl had higher plasma adrenomedullin levels than healthy subjects by 78% (P < 0.05), 131% (P < 0.001), and 214% (P < 0.001), respectively. Moreover, adrenomedullin showed intimate correlations with norepinephrine, atrial natriuretic peptide, and cAMP in plasma (r = 0.625, P < 0.001; r = 0.656, P < 0.001; and r = 0.462, P < 0.001; respectively). Thus, plasma adrenomedullin is supposed to increase in association with changes in sympathetic nervous activity and body fluid volume in hypertension and renal failure. Considering its potent vasodilator effect, adrenomedullin may be involved in the defense mechanism preserving the integrity of the cardiovascular system in these disorders.
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PMID:Plasma levels of adrenomedullin, a newly identified hypotensive peptide, in patients with hypertension and renal failure. 796 64


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