Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apart from the very frequent HIV encephalitis, which lays the foundation for opportunistic infections, the most common diseases encountered in HIV-infected patients are toxoplasmosis and lymphoma; the percentage of cases of other diseases is very small. It is capital to diagnose cerebral lymphoma at an early stage in these patients who already are in a precarious general and neurological state since this type of lesion usually occurs late in the natural course of AIDS. In the differential diagnosis between toxoplasmosis and lymphoma only stereotaxic biopsy enables a positive diagnosis to be made, but imaging methods, such as CT and MRI, provide data that help guide to a diagnosis which sometimes may be definitive. Suggestive of lymphoma is a single infiltrating lesion wider than 4 cm, which is paraventricular or located in the posterior fossa, has little perilesional alteration and a short tumoral doubling time during the imaging follow-up. Suggestive of toxoplasmosis are multiple, small, annular or nodular lesions with an important perilesional inflammation and usually located in basal ganglia. In addition, in MRI the kinetics of enhancement after contrast injection is intense and occurs early in lymphoma, in contrast with the toxoplasmic abscesses, and this should provide a more specific differential diagnosis. Scintigraphic studies with somatostatin or positron emission tomography, using fluorodeoxyglucose (FDG-PET scintigraphy), also seem to be an interesting mean of making a specific diagnosis of cerebral lesion, according to a principle that is close to dynamic MRI. In lymphoma, capturing of the tracer is about 3 times greater than in infective lesions, notably the toxoplasmic ones. Imaging, therefore, is provided with tools which permit an increasingly specific approach to the primary cerebral lymphoma of AIDS, the definitive diagnosis of which rests on stereotaxic biopsy. This high specificity facilitates a better selection of patients requiring this procedure and shortens the delay in its execution.
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PMID:[The diagnosis of primary cerebral lymphoma in AIDS. The contribution of imaging]. 747 39

With the variety of radiopharmaceutical agents and refined imaging techniques, thyroid and parathyroid imaging provides much valuable clinical information. The use of imaging is most important in the follow-up of differentiated (DTC) and medullary thyroid cancer (MTC). Patients with DTC are followed with serum thyroidglobulin and 131I whole body scintigraphy when the serum thyroglobulin level is elevated. When the 131I scintigram is negative, 201Tl scintigraphy may best identify the site of recurrent DTC. Alternative radioisotopes, ultrasound, CT, and FDG PET are also useful in localizing the site of DTC metastases. MTC recurrences and metastases are more difficult to image. Selective venous catheterization is the most sensitive and specific method for detecting areas of recurrent MTC. High-resolution ultrasound, CT, MR imaging, and scintigraphy are all capable of, and useful in, detecting macroscopic foci of metastatic tumor. Somatostatin receptor scintigraphy and 99mTc DMSA have been the most frequently used nuclear imaging agents in patients with recurrent MTC. Imaging for hyperparathyroidism remains controversial. Sestambi has become the preferred isotope for parathyroid scintigraphy; whereas high-resolution ultrasound is also frequently used. Preoperative imaging is being used as a method to allow a unilateral neck exploration, more recently, in conjunction with intraoperative 1-84 PTH assay and with intraoperative use of the gamma probe. Most often, parathyroid imaging is performed before reoperation for persistent hyperparathyroidism.
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PMID:The use of imaging studies in the diagnosis and management of thyroid cancer and hyperparathyroidism. 982 66

Although radiography, computed tomography and magnetic resonance imaging are still the methods of choice for the study of lung cancer, they have certain limitations in the determination of the nature of suspicious lung nodules, the evaluation of mediastinal involvement, the assessment of the viability of previously treated lesions and the diagnosis of tumour relapse. There is a wide range of current oncological requirements related to lung cancer: detection of malignant lesions at the earliest stage and in the most effective way; the definition of the biological characteristics of a lesion (proliferation, aggressiveness, differentiation, etc.); the need to define the operability of the patient (function of residual lung and staging); and the need to evaluate the behaviour of the tumour (response to therapy, early detection of recurrences, metastatic spread). Most of the efforts of the nuclear medicine community have been focussed on diagnosis, staging, restaging and therapy monitoring of lung cancer. Many radiopharmaceuticals have been employed for this, including gallium, monoclonal antibodies, somatostatin analogues, lipophilic cations and positron emission tracers. There is ample evidence that nuclear medicine techniques may provide complementary information with respect to anatomical imaging, for example in the assessment of preoperative function by means of ventilation and perfusion scintigraphy, or in tumour localisation by means of specific tumour-seeking agents. However, clinical data suggest that, when properly used, nuclear medicine procedures in some cases may be not only complementary to radiology but essential for the clinical management of lung cancer. An example of such a procedure is fluorodeoxyglucose positron emission tomography (FDG PET) the introduction of which has greatly contributed to confirmation of the clinical value of nuclear medicine in this field. FDG PET has proved of great help in lung cancer management and its cost-effectiveness in lung cancer staging is firmly established. In this review the results of the most important nuclear medicine techniques are summarised and their value in clinical practice is discussed. General, updated information is provided about the epidemiology, biology and clinical management of lung cancer, and about the role of nuclear medicine in these areas.
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PMID:Nuclear medicine procedures in lung cancer. 1038 99

Two patients with widely metastatic papillary thyroid cancer demonstrated progressive growth of diffuse pulmonary lesions. One patient had no apparent response to high doses of 131I and the other hand no 131I uptake. 111In-pentetreotide scans revealed that many of the metastatic lesions expressed somatostatin receptors. The baseline metabolic activity and three-dimensional volume of the lesions were determined by 18F-fluoro-de-oxyglucose positron emission tomography (FDG-PET). After 3 or 4 months of octreotide (Sandostatin LAR Depot; Novartis Pharmaceutical, East Hanover, NJ) therapy, repeat FDG-PET scans revealed reductions in tumor volume and decreases in the standard uptake values of FDG. We conclude that octreotide therapy can change the biological activity of metastatic thyroid cancer lesions that exhibit somatostatin receptors.
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PMID:Inhibition of metabolic activity in papillary thyroid carcinoma by a somatostatin analogue. 1071 56

Malignant paraganglioma is a rare and slow growing tumour of neuroendocrine origin. At the time of diagnosis, the tumour is usually widespread, with limited therapeutic options. A variety of functional imaging studies are available for staging the disease, guiding therapy and monitoring treatment response. These include 123I-MIBG or 131I-MIBG, 111In-pentetreotide or 111In-lanreotide (somatostatin analogues), and 18F-FDG positron emission tomography. Various radionuclides, including 131I and 90Y, can be targeted to the tumour using MIBG or pentetreotide. Such targeted radionuclide therapy may provide valuable long-term palliation in such patients. We present two cases with metastatic paragangliomas who had widespread soft tissue and bone metastases. One patient was treatment naive and the second had received previous chemotherapy. The functional imaging work-up performed and the targeted radionuclide therapies considered in these patients are described. Both patients were treated with 131I-MIBG. Partial tumour response and complete symptomatic and hormonal response was achieved in one patient; in the second patient there was no change.
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PMID:Functional imaging as an aid to decision-making in metastatic paraganglioma. 1133 5

Medullary thyroid carcinoma (MTC) originates in the parafollicular cells (C cells) of the thyroid, secreting both calcitonin and CEA. Genetic and biochemical testing allow early pre-clinical identification of familial forms. Sporadic MTC usually presents as a solitary palpable thyroid nodule and in most cases the definitive diagnosis is established only at the time of surgery. Nuclear medicine procedures, which play a minor role in the preoperative evaluation of MTC, are essential in postoperative follow-up to detect residual and/or recurrent tumor. A number of radiopharmaceuticals are able to visualize MTC lesions with considerable advantages in diagnosis and prognosis, some of them having also a therapeutic role. Among them, 99mTc[V]DMSA shows the highest diagnostic sensitivity and is considered by many authors the radiopharmaceutical of choice in the postoperative work-up of MTC. Radioiodinated MIBG, in spite of its high specificity has a poor sensitivity (30%); however it is useful for the identification of pheochromocytoma and, in patients showing MIBG uptake in tumoral lesions, high activities of 131I-MIBG may be used for therapy. 111In labeled octreotide detects lesions which express somatostatin receptors; a positive scintigraphic result seems to give also prognostic information (higher uptake in slow-growing lesions) and provides the basis for treatment with octreotide or lanreotide and 111In or 90Y-labeled octreotide analogues. Interesting perspectives are offered by 18F-FDG PET and monoclonal anti-CEA labeled antibodies; the latter may be also used for therapy.
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PMID:Role of nuclear medicine in the diagnosis and therapy of medullary thyroid carcinoma. 1137 May 45

F-18 FDG PET in patients with nonendocrine pancreatic cancer and somatostatin receptor imaging in patients with endocrine pancreatic cancer have an important role in detecting or confirming the presence of a mass in the pancreas--a crucial step in the management of these patients. Both agents also have an important role in staging and in defining which patients are good candidates for resection surgery. Somatostatin receptor imaging also has a crucial role in selecting from the various systemic therapeutic options available. I-131 MIBG therapy can be of value therapeutically, mostly palliative, in patients who demonstrate a markedly elevated concentration of tumor radioactivity.
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PMID:The role of nuclear medicine in the evaluation of pancreatic disease. 1139 21

Several tumors overexpress somatostatin receptors (SSTR) and can thus be imaged with radiolabeled analogues of somatostatin. Tc-99m depreotide is a new radiolabeled somatostatin analogue that shows high affinity for SSTR2, SSTR3, and SSTR5 subtypes. It has been recently FDA-approved for use in the evaluation of indeterminate solitary pulmonary nodules. SPECT with Tc-99m depreotide is highly accurate in this clinical setting and may be preferable to FDG-PET because of its lower cost and wider availability. Large studies are also underway to evaluate the accuracy of Tc-99m depreotide in staging of lung cancer.
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PMID:Somatostatin receptor imaging of non-small cell lung cancer with 99mTc depreotide. 1196 4

The following article reviews nuclear medicine techniques which can be used for assessment of endocrine disorders of the hypothalamic-pituitary axis. For planar and SPECT imaging somatostatin-receptor- and dopamine-D2-receptor-scintigraphy are the most widely distributed techniques. These nuclear medicine techniques may be indicated in selected cases to answer differential diagnostic problems. They can be helpful to search for presence and localization of receptor positive tissue. Furthermore they can detect metastasis in the rare cases of a pituitary carcinoma. Scintigraphy with Gallium-67 is suitable for further diagnostic evaluation in suspected hypophysitis. Other SPECT radiopharmaca do not have relevant clinical significance. F-18-FDG as PET radiopharmacon is not ideal because obvious pituitary adenomas could not be visualized. Other PET radiopharmaca including C-11-methionine, C-11-tyrosine, F-18-fluoroethylspiperone, C-11-methylspiperone, and C-11-raclopride are available in specialized centers only. Overall indications for nuclear medicine in studies for the assessment of endocrine disorders of the hypothalamic-pituitary-axis are rare. Original studies often report only about a small number of patients. According to the authors' opinion the relevance of nuclear medicine in studies of clinically important endocrinologic fields, e.g. localization of small ACTH-producing pituitary adenomas, tumor localization in ectopic ACTH syndrome, localization of recurrent pituitary tissue, assessment of small incidentalomas, can not be definitely given yet.
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PMID:[Assessment of endocrine disorders of the hypothalamic-pituitary axis by nuclear medicine techniques]. 1198 2

Molecular imaging can reveal in vivo analysis and quantification of biochemical reactions. To enable cell-surface imaging of receptors, novel ligands have been developed which can be radiolabeled or imaged by bioluminescence. Specific examples include somatostatin receptors, estrogen and progesterone receptors, receptors involved in adhesion and externalization of phosphatidyl serine as an indicator of apoptosis. Central nervous system imaging can be carried out using ligands for receptors including dopamine, serotonin and Gamma amino butyric acid (GABA). In addition, tumor and metabolic imaging can be carried out with the Na-K ATPase pump using the tracer thallium-201 for SPECT or F-18 FDG for PET imaging. Finally, novel receptors or endogenous metabolic pathways can be analyzed combining cell-gene therapy to create specific tracer targets in cells that can be studied by molecular imaging. The challenge of molecular imaging is to first identify key pathways that are unique for a specific disease processes, such as atherosclerosis, cancer, CNS disorders, immunologic and arthritis disorders and next to devise a high-affinity specific small molecular ligand that can be adapted to be a radiolabeled tracer to study this pathway. Advances in genomics and proteomics combine with new peptide-chemistry approaches should provide a large number of targets and tracers in the near future to achieve these imaging objectives.
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PMID:Molecular imaging: new applications for biochemistry. 1255 16


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