Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pheochromocytoma accounts for about 0.1 per cent of patients with diastolic hyperstension. It mimics many diseases varying from anxiety psychoneurosis to intracranial tumors. Cardinal symptoms include sevre headache (72 to 92 per cent), sweating (60 tp 70 per cent), palpitations (51 to 73 per cent), and hypertension (> 90 per cent) of which 50 per cent is sustained, 50 per cent paroxysmal. Many drugs (phenothiazines, Saralasin, antiemetics, steroids, etc.) have been reported as precipitating factors. Patients who should be screened for pheochromocytoma include: (1) all symptomatic patients with sustained or paroxysmal hyperstension; (2) asymptomatic hypertension; (3) all patients with MEA 2a,b (hyperparathyroidism, medullary carcinoma of the thyroid, neurocutaneous lesions) and their first degree relatives, even if the latter are asymptomatic and normotensive; (4) hypertension plus diabetes mellitis or hypermetabolism; (5) hypertensive episode during induction of anesthesia or radiologic procedure; and (6) hypertensive response during histamine administration, i.e., gastric analysis. Urinary metanephrine is the single best screening test. Plasma catecholamine determination is particularly helpful when collected before and immediately after an attack. Provacative agents (histamine, glucagon, tyramine) are needed rarely. Preoperative localization of the tumor can be done with nephrotomography IVP, computerized axial tomography, ultrasound, 131-I-19-iodocholesterol scan, arteriography, venography.
 ...
PMID:Pheochromocytoma: clinical manifestations and diagnostic tests. 745 90

Pheochromocytoma is mainly characterized by a great deal of variability in its biological activity and in its clinical manifestations. This special feature has always to be taken into account in any diagnostic procedure. The tumor is generally suspected on clinical ground for the presence of paroxysmal hypertension but this sign is largely aspecific and often absent. The diagnosis of pheochromocytoma has to be based on laboratory tests demonstrating an excess and/or a disregulation in catecholamine (CA) secretion. CA or CA metabolites can be measured in urine or blood. Whatever the sample measured, it is important to correlate its result with the clinical picture found during its collection. Basal plasma CA concentrations are often raised also during periods of normotension but their accuracy is the highest in samples drawn during a hypertensive crisis. When basal measurements are insufficient for a final diagnosis, inhibitory (clonidine) or stimulatory (glucagon) tests can be performed. Clonidine test is recommended in patients showing slight increases in basal plasma CA. Glucagon stimulation test should be performed only in normotensive patients with an incidental adrenal mass, patients with sporadic hypertensive crises or members of families affected by MEN II. Localization procedures are mainly based on CT (or MRI) and on scintigraphy with I131-MIBG. CT possesses high sensitivity (about 96%) while I131-MIBG scintigraphy possesses a very high specificity (about 97%). Therefore, both the procedures should be performed before surgery. Rarely, it is also necessary to perform catheterization of the venous tree and plasma sampling for CA measurement to localize the tumor through the discovery of a secretory gradient.
 ...
PMID:[Diagnostic problems in pheochromocytoma]. 765 Dec 83

Pheochromocytomas in patients with von Hippel-Lindau (VHL) syndrome and multiple endocrine neoplasia type 2 (MEN 2) differ in the types and amounts of catecholamines produced and the resulting signs and symptoms. We hypothesized the presence of different processes of catecholamine release reflecting differential expression of components of the regulated secretory pathway among the two types of hereditary tumors. Differences in catecholamine secretion from tumors in patients with VHL syndrome (n = 47) and MEN 2 (n = 32) were examined using measurements of catecholamines in tumor tissue, urine, and plasma, the last of which was under baseline conditions in all subjects and in a subgroup of patients who received intravenous glucagon to provoke catecholamine release. Microarray and proteomics analyses, quantitative PCR, and Western blotting were used to assess expression of tumor tissue secretory pathway components. The rate constant for baseline catecholamine secretion was 20-fold higher in VHL than in MEN 2 tumors (0.359 +/- 0.094 vs. 0.018 +/- 0.009 day(-1)), but catecholamine release was responsive only to glucagon in MEN 2 tumors. Compared with tumors from MEN 2 patients, those from VHL patients were characterized by reduced expression of numerous components of the regulated secretory pathway (e.g., SNAP25, syntaxin, rabphilin 3A, annexin A7, calcium-dependent secretion activator). The mutation-dependent differences in expression of secretory pathway components indicate a more mature regulated secretory pathway in MEN 2 than VHL tumors. These data provide a unique mechanistic link to explain how variations in the molecular machinery governing exocytosis may contribute to clinical differences in the secretion of neurotransmitters or hormones and the subsequent presentation of a disease.
 ...
PMID:Differential expression of the regulated catecholamine secretory pathway in different hereditary forms of pheochromocytoma. 1885 24