Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0007095 (carcinoid)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 24-hour urine collection for 5-hydroxyindoleacetic acid (HIAA) is commonly performed to evaluate patients with suspected carcinoid syndrome. However, carcinoids are rare, and elevated results are common even when using an analytically specific method. To characterize this problem, the incidence of elevated results was examined in a population of 947 patient specimens received in a clinical reference laboratory setting. Using a reference limit of 15 mg/d identified 7.9 percent of the results as elevated, with 3 percent > 100 mg/d, and about 1 percent > 350 mg/d. Males showed 14 percent > 15 mg/d compared to 5.2 percent for females. Characterization of incomplete and excess 24-hr urine collections is facilitated by use of a creatinine ratio, with a reference limit of 14 mg/g creatinine equivalent to 15 mg/d. Given the frequency of elevated results, HIAA should be used to support the diagnoses of carcinoid only when consistent with other objective findings.
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PMID:The incidence of elevations in urine 5-hydroxyindoleacetic acid. 964 59

The effect of short-term treatment with the highly selective serotonin receptor antagonist ondansetron on symptoms and gastric emptying in 11 carcinoid patients was studied. Diarrhoea improved in 6 of 6 patients, nausea in 3 of 4 patients. Flushing was not affected. The rate of gastric emptying increased during ondansetron treatment (P = 0.08). No changes in serotonin in platelets and urinary excretion of 5-hydroxyindoleacetic acid were found. It is concluded that ondansetron can improve gastrointestinal symptoms in carcinoid patients and possibly slows gastric emptying.
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PMID:Effects of ondansetron on gastrointestinal symptoms in carcinoid syndrome. 984 94

Two case-reports of metastatic bone disease in patients with bronchial carcinoid tumors illustrate the diagnostic challenges raised by these slowly-growing malignancies of which the primary frequently escapes early identification. The first patient had the typical picture of a primary with a single bone metastasis. Unusual features in the second patient were the large number of bone metastases, involvement of distal skeletal sites, and elevation of serotonin and 5-hydroxyindoleacetic acid levels.
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PMID:Bone metastases from bronchial carcinoid tumors. Two case-reports. 1003 99

A 38-year-old woman presented with hypertension and a renal cell carcinoma. Raised urinary 5-hydroxyindoleacetic acid values >300 micromol/l, predictive of carcinoid tumour, were found during the perioperative period. The values returned towards normal 2 weeks post-surgery. Immunohistochemical examination of the renal cell carcinoma with neuroendocrine markers was negative. Despite a diligent search, no carcinoid tumour could be identified and the patient was well 4 years later. There was no dietary or drug explanation for this pseudocarcinoid.
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PMID:Renal cell carcinoma presenting as a pseudo-carcinoid tumour. 1050 48

Positron emission tomography (PET) performed with various radiolabelled compounds facilitates the study of tumor biochemistry. If the tumor uptake of an administered tracer is greater than that of surrounding normal tissue, it is also possible to localize the tumor. In initial studies, 18F-labeled deoxyglucose (FDG) was attempted to visualize the tumors, since this tracer had been successfully used in oncology, reflecting increased glucose metabolism in cancerous tissue. However, this tracer was not to any significant degree taken up by the neuroendocrine tumors. Instead, the serotonin precursor 5-hydroxytryptophan (5-HTP) labeled with 11C was used and showed an increased uptake and irreversible trapping of this tracer in carcinoid tumors. The uptake was selective and the resolution so high that we could detect more liver and lymph node metastases with PET than with CT or octreotide scintigraphy. One problem was, however, the high renal excretion of the tracer producing streaky artifacts in the area of interest. Using the decarboxylase inhibitor carbidopa, given as peroral premedication, the renal excretion decreased 6-fold and at the same time the tumor uptake increased 3-fold, hence improving the visualization of the tumors. When patients were followed during treatment with PET using 5-HTP as a tracer, a > 95% correlation between changes in urinary 5-hydroxyindoleacetic acid (U-5-HIAA) and changes in the transport rate constant for 5-HTP was observed. Thus, PET can be used to monitor treatment effects. Elevation of U-5-HIAA is considered to be uncommon in endocrine pancreatic tumors (EPTs). Initially, 11C-labeled L-DOPA was attempted as another amine important in the APUD system. With L-DOPA about half of the EPTs, mainly functioning tumors, could be detected. Recently, 5-HTP was explored as a universal tracer also for EPT and foregut carcinoids, extending the PET-examination to both thorax and abdomen (whole-body PET-examination). With this method we were able to visualize small lesions in the pancreas and thorax (e.g. ACTH-producing bronchial carcinoids) not detectable by any other method including octreotide scintigraphy, MRI and CT. Several other tracers have been investigated, e.g. the monoamineoxidase (MAO-A) inhibitor harmine with promising results in non-functioning EPTs. We are currently exploring a wide range of biochemical systems, including enzymes and receptors, both for neurotransmitters and for peptides and proteins in in vitro assays with the potential to use some of the developed tracers for in vivo visualization and tumor biological studies. In conclusion, PET is a valuable tool in the diagnosis of neuroendocrine tumors. It can detect small lesions in the thorax and abdomen not detected by other methods, which has been of great value preoperatively in several cases. It detects more lesions in the liver and lymph nodes than other methods and furthermore, it can be used to monitor treatment effects.
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PMID:Use of PET in neuroendocrine tumors. In vivo applications and in vitro studies. 1093 3

Analyses of serotonin and other 5-hydroxyindoles, such as its precursor 5-hydroxytryptophan and major metabolite 5-hydroxyindoleacetic acid (5-HIAA), are indispensable for the elucidation of their (patho)physiological roles. In clinical chemistry attention is mainly focused on the diagnosis and follow-up of carcinoid tumours. For this most laboratories routinely measure urinary 5-HIAA. More recently, measurements of serotonin in platelets and urine have been advocated. Platelet serotonin may be the most sensitive indole marker for the detection of carcinoid tumours that secrete only small amounts of serotonin and/or its precursor 5-hydroxytryptophan. Although several chromatographic techniques have emerged for the analysis of tryptophan-related indoles, HPLC with either electrochemical or fluorometric detection have become the methods of choice for their quantification. HPLC-based methods combine selectivity, sensitivity and high precision, and enable the simultaneous investigation of several metabolically related indoles. This review aims to place the analysis of indoles in biological matrices in a biochemical, physiological and clinical perspective and highlights several important steps in their chromatographic analysis and quantification.
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PMID:Clinical chemistry of serotonin and metabolites. 1110 98

A 69-year-old woman was admitted with facial flushing, weight loss and intermittent diarrhoea. Urinary 5-hydroxyindole-acetic acid (5-HIAA) level was elevated at 200 micromol/24 h (normal: < 50). Computerized tomography (CT) demonstrated multiple enhancing liver metastases with biopsy proven carcinoid metastases with no evidence of primary tumour at this stage. Octreotide was initiated, resulting in marked improvement in carcinoid symptoms. Nine years later, she presented with abdominal pain and slightly deranged liver function tests. Repeat colonoscopy at this stage, showed an ileal tumour causing impending obstruction, necessitating urgent right hemicolectomy. Histology demonstrated primary carcinoid tumour. She continued on octreotide. Three years later at the age of 81 years, she suffered a fatal haemorrhagic stroke. Autopsy revealed complete regression of hepatic carcinoid metastases.
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PMID:Complete histological regression of metastatic carcinoid tumour after treatment with octreotide. 1115 85

A comparison has been made of [(123)I]meta-iodobenzylguanidine ([(123)I]MIBG) and [(111)In]pentetreotide scintigraphy in 54 patients with a variety of neuroendocrine tumors of whom 46 patients had metastatic disease. [(111)In]Pentetreotide scintigraphy was more sensitive in detecting metastatic lesions, as demonstrated on computed tomography and/or magnetic resonance scanning, than [(123)I]MIBG: 67% vs. 50% for carcinoid tumors (n = 24), 91% vs. 9% for pancreatic islet cell tumors (n = 12), 100% vs. 60% for medullary thyroid carcinomas (n = 5), and 75% vs. 100% for pheochromocytomas/paragangliomas (n = 4). In only 2 patients were lesions seen with [(123)I]MIBG scanning that were not apparent with [(111)In]pentetreotide. With the exception of pancreatic islet cell tumors, both radionuclides exhibited a similar sensitivity in detecting hepatic metastases, whereas in three patients the two radionuclides exerted a complementary role as different deposits exhibited uptake to only 1 or the other radionuclide. Hepatic metastases were the most important clinical predictor of a positive scan for both radionuclides. Neither elevated 5-hydroxyindoleacetic acid levels nor any other hormonal marker was predictive of a positive scan. In 8 patients with clinical and/or hormonal evidence of a neuroendocrine tumor but negative conventional radiology, [(111)In]pentetreotide scintigraphy was more sensitive than [(123)I]MIBG (37.5% vs. 12.5%) in detecting lesions. In conclusion, scintigraphy with [(111)In]pentetreotide detects more metastatic lesions than [(123)I]MIBG in patients with carcinoid and pancreatic islet cell tumors and medullary thyroid carcinomas; [(123)I]MIBG scintigraphy may be more sensitive for sympathoadrenomedullary tumors. The radionuclides may exert a complementary role in the detection and treatment of neuroendocrine tumors in occasional patients, as areas of different pattern of uptake were identified within the same patient. These data have implications not only for staging such tumors, but also for identifying patients who might benefit from treatment using either [(131)I]MIBG or radioactive somatostatin analogs.
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PMID:Comparison of somatostatin analog and meta-iodobenzylguanidine radionuclides in the diagnosis and localization of advanced neuroendocrine tumors. 1115 63

Patients with metastatic carcinoid tumours often undergo surgical procedures to reduce the tumour burden and associated debilitating symptoms. These procedures and anaesthesia can precipitate a life-threatening carcinoid crisis. To assess perioperative outcomes, we studied retrospectively the medical records of adult patients from 1983 to 1996 who underwent abdominal surgery for metastatic carcinoid tumours. Preoperative risk factors, intraoperative complications and complications occurring in the 30 days after surgery were recorded. Perioperative complications or death occurred in 15 of 119 patients (12.6%, exact confidence interval 7.2-19.9). None of the 45 patients who received octreotide intraoperatively experienced intraoperative complications compared with eight of the 73 patients (11.0%) who did not receive octreotide (P=0.023). The presence of carcinoid heart disease and high urinary output of 5-hydroxyindoleacetic acid preoperatively were statistically significant risk factors for perioperative complications.
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PMID:Perianaesthetic risks and outcomes of abdominal surgery for metastatic carcinoid tumours. 1151 30

We report a unique case of a patient with a neuroendocrine tumor localized to the bone marrow. The patient had a history of hairy cell leukemia, and the neuroendocrine tumor was detected in a bone marrow biopsy specimen obtained to assess response to 2-chlorodeoxyadenosine therapy. The neuroendocrine tumor was present as nodules that replaced approximately 15% of the bone marrow medullary space and was composed of round cells with fine chromatin, indistinct nucleoli, and relatively abundant, granular, eosinophilic cytoplasm. Histochemical stains showed cytoplasmic reactivity with Grimelius and Fontana-Masson stains, and immunohistochemical studies showed positivity for keratin and chromogranin. The histologic, cytochemical, and immunohistochemical features resembled a carcinoid tumor, and metastasis to the bone marrow was considered initially. The patient was asymptomatic without diarrhea, flushing, or cardiac valve disease. Serotonin production, assessed by the measurement of serum 5-hydroxyindoleacetic acid and substance P levels, was normal. Extensive clinical and radiologic work-up and endoscopy of the gastrointestinal tract to detect a primary site other than the bone marrow were negative. Follow-up bone marrow biopsy 7 years after the initial diagnosis was positive for persistent neuroendocrine tumor. The patient has not received any therapy specific for the neuroendocrine tumor and has had no clinical symptoms or evidence of progression after 9 years of clinical follow-up. We suggest that this neuroendocrine tumor may have arisen in the bone marrow.
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PMID:Indolent neuroendocrine tumor involving the bone marrow. A case report with a 9-year follow-up. 1268 82


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