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Query: UMLS:C0031511 (pheochromocytoma)
 14,622 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neurohumoral mechanisms operating via the catecholamines are discussed in their relationship to such hypertensive diseases as pheochromocytoma and labile and established essential hypertension. 2. In pheochromocytoma, diagnosis depends almost entirely on identification of increased amounts of catecholamine metabolites in the urine. Because of the danger, manipulative or invasive procedures both for diagnosis and during surgery should be kept at a minimum. 3. In established essential hypertension, reactivity to norepinephrine and plasma norepinephrine are increased, whereas norepinephrine uptake and apparent secretion rate are decreased. 4. In labile essential hypertension, reactivity to epinephrine and probably plasma epinephrine are increased and uptake of epinephrine decreased. 5. Labile hypertension with all its characteristics may or may not coexist with established essential hypertension with all its features. 6. The sympathetic nervous system is also involved in other types of hypertensive disease. Many patients with renovascular hypertension as well as with primary and secondary hyperaldosteronism also have essential hypertension. Angiotensin II affects the sympathetic nervous system and the juxtaglomerular apparatus appears to be beta adrenergic receptor activated, at least in part.
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PMID:Neurohumoral mechanisms in hypertension. 23 64

To test whether central neurogenic factors participate in blood pressure elevation in primary hypertension, we studied the concentrations of: norepinephrine, epinephrine and dopamine-beta-hydroxylase (DBH) in cerebrospinal fluid (CSF); and norepinephrine, epinephrine, DBH and plasma renin activity (PRA) in plasma of 22 subjects (seven with primary hypertension, 11 normotensive patients with non-systemic neurological disorders, and four with secondary hypertension). Plasma and CSF norepinephrine (NE) were increased in primary hypertensives compared to normotensives. Cerebrospinal fluid norepinephrine was related to diastolic blood pressure, and systolic blood pressure when normotensive and primary hypertensives were taken together. The CSF norepinephrine of primary hypertensive patients was correlated with natural log PRA. The CSF norepinephrine was correlated inversely with age in primary hypertensive patients but not in the normotensive subjects. The low CSF norepinephrine and epinephrine, despite markedly increased plasma NE and epinephrine, in two patients with pheochromocytoma, indicate a blood-brain barrier for these neurohormones. The observations support the view that the central sympathetic nervous system is involved in the pathogenesis of primary hypertension, particularly in younger patients.
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PMID:Raised cerebrospinal fluid norepinephrine in some patients with primary hypertension. 39 37

The feasibility of differentiating patients with pheochromocytoma from other hypertensive patients by measuring urinary excretion rates of norepinephrine during sleep, a period of physiologic suppression of norepinephrine release, was investigated. The mean excretion rates of norepinephrine in 248 normal subjects and in 109 patients with essential hypertension were 1.03 +/- 0.03 and 1.12 +/- 0.06 (SEM) micrograms/hour, respectively, whereas the lowest excretion rate among the six patients with pheochromocytoma was about seven times higher. Plasma norepinephrine concentration in patients with pheochromocytoma was also consistently above the range observed in both normotensive and hypertensive subjects. CT scan correctly identified the same tumors visualized by selective arteriography. It is suggested that the usefulness of these approaches will provide simpler means of screening and detecting pheochromocytoma.
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PMID:Diagnosis and localization of pheochromocytoma. Detection by measurement of urinary norepinephrine excretion during sleep, plasma norepinephrine concentration and computerized axial tomography (CT-scan). 46 12

Patients with essential hypertension were treated for four weeks with the alpha- and beta-adreno-receptor blocking agent labetalol. Urinary excretion of total catecholamines, metanephrine plus normetanephrine and vanillylmandelic acid was measured with various methods before and during treatment. An unidentified substance interfering with the fluorimetric method for catecholamines and the photometric assay for metanephrines caused falsely high values of those substances. Using appropriate methodology no changes of total catecholamines, metanephrine plus normetanephrine and vanillylmandelic acid excretion were found after labetalol therapy. Our findings are important in preventing errors in the diagnosis of pheochromocytoma as well as in the evaluation of the effects of labetalol on the sympathetic nervous system in man.
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PMID:Increased catecholamine excretion after labetalol therapy: a spurious effect of drug metabolites. 52 20

Aberrations in the metabolic pathways of catecholamines in patients with neural crest tumors result in characteristic urinary excretion patterns of their catabolites. Tumors such as pheochromocytoma, neuroblastoma and ganglioneuroma usually defy clinical diagnosis because of their rarity, small size, intraabdominal position and clinical symptoms similar to those of essential hypertension. Quantitative determination of catecholamine metabolites such as vanillylmandelic acid (VMA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) offers possibilities for reliable confirmation of diagnosis. However, previous techniques for the assessment of catabolite levels suffered from inadequate sensitivity, reproducibility or specificity, which seriously diminished their usefulness as biochemical determinants in the prognosis of these life-threatening tumors. Reported in this paper is the analysis of urinary levels of VMA and MHPG using reversed-phase high-performance liquid chromatography with electrochemical and sectrophotometric detection. We present the excretion patterns showing these metabolites in 15 control subjects, 15 patients with pheochromocytoma and 5 patients with neuroblastoma.
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PMID:Diagnosis of neural crest tumors by reversed-phase high-performance liquid chromatographic determination of urinary catecholamine metabolites. 54 40

The relation of plasma dopamine beta-hydroxylase (DBH) activity to age was examined in normotensive and hypertensive subjects. Plasma DBH activity was the highest in the group of 25--34 years and gradually decreased with age. Plasma DBH activity was higher in the hypertensives than in the normotensives in all age groups, and the difference was significant between the groups of 45--54 and 55--64 years. Plasma DBH activity was increased in labile hypertension. Plasma DBH activity was higher in the group of essential hypertension with normal renal function than in that with reduced renal function. It was lower in the severe hypertensives than in the mild cases. Plasma DBH activity was also decreased in the hypertensive patients with cerebrovascular disorders. Plasma DBH activity was lower in the hypertensive patients with renal parenchymal diseases than those of essential hypertension with normal renal function. Plasma DBH activity was also decreased in primary aldosteronism, while it was increased in pheochromocytoma. These observations suggest that measurement of plasma DBH activity may be valuable in the differentiation of essential hypertension from the secondary forms of hypertension, and the evaluation of the hypertensive processes. To evaluate plasma DBH activity, it is important to consider its age-related changes.
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PMID:The evaluation of plasma dopamine beta-hydroxylase activity in essential and secondary hypertension. 57 40

To facilitate the screening for pheochromocytoma, we have validated the use of single-voided, spot urine specimens for the determination of total metanephrines. Metanephrine excretion was found to be quite constant throughout the day and night in ten patients with essential hypertension and seven patients with pheochromocytoma. The levels in single-voided specimens were closely correlated to those in 24-hour specimens in 100 hypertensive subjects. The mean +/- 2 SD metanephrine excretion in single-voided urine specimens from 500 hypertensive subjects was 0.351 +/- 0.356 mug/mg of creatinine.
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PMID:Single-voided urine metanephrine assays in screening for pheochromocytoma. 83 17

The reliability of the angiotensin II (AT II)-antagonist Saralasin in the diagnosis of AT II-dependent forms of hypertension was investigated in 61 cases of hypertension of different etiology. In 14 patients, lowering of blood pressure by Saralasin suggested an AT II-dependent hypertension which could be ascertained in 8 patients (5 had undergone successful surgery) by increased levels of plasma-renin-activity (PRA), AT II, PRA-ratio in renal vein blood and by angiography. Besides, depressor reactions by Saralasin yielded additional information in three patients with renovascular hypertension but normal levels of PRA and AT II, in two patients with high renin essential hypertension and one patient with pheochromocytoma. This test seems to be valuable in the diagnosis of renin-dependent hypertension.
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PMID:[Critical analysis of the saralasintest in the diagnosis of hypertension (author's transl)]. 89 3

The urinary excretion of free noradrenaline (NA), adrenaline (A), dopamine (DA), the DA/NA ratio in the urine, plasma renin activity (PRA) and their mutual relationship were investigated in 71 patients suffering from different types of arterial hypertension. In spite of the fact that the mean values of excreted catecholamines, with the exception of pheochromocytoma, lie within the range of values found in healthy controls, certain differences were found in spectrum of excreted catecholamines. In patients with labile, malignant and renovascular hypertension and in pheochromcytoma the higher mean excretion of NA and the low DA/NA ratio was accompanied by the higher PRA in comparison with fixed benign essential hypertension. On the other hand, in hypertension with low PRA (essential hypertension with suppressed renin and Conn's syndrome) a low excretion of NA and high DA/NA ratio was found. There was a significant, if not even very close negative correlation between the PRA and DA/NA ratios both in recumbent and upright position. The rise of PRA on standing up was followed by an increased excretion of NA while the excretion of DA did not change or decreased. Hence the DA/NA ratio when standing up showed a decreasing tendency as compared with values when lying down. Application of the beta-blocker Inderal decreased the PRA and the blood pressure not only in juvenile hypertensive patients with hyperkinetic circulation but also in the early phases of renovascular hypertension. It thus appears that endogenous catecholamines, first of all the ratio between the renin-inhibiting DA and the renin-stimulating NA, participate as one of several factors in the regulation of secretion and of the plasma levels of renin not only in juvenile hypertensive patients with hyperkinetic circulation but also in other types of hypertension.
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PMID:Relationship between plasma renin activity and urinary catecholamines in various types of hypertension. 97 8

The content of total metabolizing sodium was studied in 74 patients with hypertension of different genesis, using the Na24-isotope dilution technique. Among these patients 31 had essential hypertension, 43--symptomatic hypertension (40--renal, and 3--adrenal). In Stage IB and IIA hypertension, a reduction of the level of total metabolizing sodium and its increased urine excretion were found. At late stages of essential hypertension, like in symptomatic renal hypertension, normal levels of total metabolizing sodium were found, or a slight tendency towards its elevation. In cases of adrenal hypertension (Conn's syndrome, pheochromocytoma) the level of total metabolizing sodium is significantly elevated. No correlation was seen between the levels of total metabolizing sodium, and plasma and erythrocytes sodium. The decrease of total metabolizing sodium at early stages of essential hypertension must be an adaptative reaction of the body, which is proved by the increased urine excretion of sodium.
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PMID:[Content of total metabolic sodium in arterial hypertension of varying origin]. 97 79


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