| 11. |
- Grönberg, Malin, et al.
(författare)
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Ghrelin and Obestatin in Human Neuroendocrine Tumors : Expression and Effect on Obestatin Levels after Food Intake
- 2013
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 97:4, s. 291-299
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Tidskriftsartikel (refereegranskat)abstract
- Background:Ghrelin and obestatin are derived from the same peptide hormone precursor and are mainly produced by the gastric mucosa. Ghrelin is involved in many biological processes, whereas the physiological function of obestatin needs further investigation. The aims of the present study were to establish the incidence of ghrelin- and obestatin-immunoreactive cells in a comprehensive panel of human neuroendocrine tumors (NETs) and to investigate if blood obestatin concentrations are influenced during a standardized meal stimulation test in healthy individuals and patients with NETs.Materials and Methods:The expression of ghrelin and obestatin was investigated in NETs (n = 149) and other endocrine-related disorders (n = 3) using immunohistochemistry with specific polyclonal antibodies. Coexpression of the peptides was evaluated by double immunofluorescence. Concentrations of obestatin in blood were measured during a meal test in 6 healthy individuals and 5 patients with pancreatic NETs.Results:Ghrelin and obestatin were expressed in 14/152 and 19/152 tumor tissues, respectively, mainly representing NETs of foregut origin and in pancreatic tissue from a nesidioblastosis patient. Double immunofluorescence staining showed colocalization of the peptides. During the meal test, obestatin levels in blood were unchanged in all patients but decreased significantly in the healthy individuals.Conclusion:Only a minority of NETs express ghrelin and obestatin. However, analysis of patients with tumors originating from tissues that express the peptides in normal conditions could be of importance. The results from the meal test indicate that the hormone levels are affected by food intake in healthy individuals, whereas obestatin levels remained unchanged in pancreatic NET patients.
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| 12. |
- Grönbladh, Alfhild, et al.
(författare)
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Recombinant Human Growth Hormone Affects the Density and Functionality of GABAB receptors in the Male Rat Brain
- 2013
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 97:3, s. 203-211
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Tidskriftsartikel (refereegranskat)abstract
- The beneficial effects of growth hormone (GH) on memory and learning have previously been confirmed in both humans and in animal models. An important role of GABA(B) receptors for multiple forms of learning and memory has also been reported. In this study, we examined the effect of GH on the density and functionality of the metabotropic GABA(B) receptors in the rat brain. Male Sprague-Dawley rats (n = 24) divided into 3 groups were injected twice daily with recombinant human GH (0.07 or 0.7 IU/kg) for 7 days. The effects of the hormone were determined by quantitative autoradiography and by GABA(B) stimulated [(35)S]-GTPγS binding using the selective GABA(B) receptor agonist baclofen. The results demonstrate moderate but significant alterations in both receptor density and functionality in a number of brain regions. For example, a dose-dependent upregulation of GABA(B) receptors was found in the cingulate cortex, primary motor cortex and caudate putamen, whereas attenuation in the receptor density was encountered in, for example, the medial geniculate nucleus. Although the GH-induced effects on the GABA(B) receptor in brain areas associated with cognition were fairly pronounced, they were significant and we propose that the physiological responses observed after GH administration at least partly can be mediated through a mechanism involving GABA(B) receptors.
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| 13. |
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| 14. |
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| 15. |
- Järhult, Johannes, et al.
(författare)
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First Report on Metastasizing Small Bowel Carcinoids in First-Degree Relatives in Three Generations
- 2010
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 91:4, s. 318-323
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: There is an established association between the multiple endocrine neoplasia type 1 (MEN 1) syndrome and foregut carcinoids. Some registry studies also indicate that offspring to carcinoid patients run an increased risk of developing a carcinoid tumor themselves. However, there are only scattered reports of gastrointestinal carcinoids in two generations. The aim of this study was to describe the clinical characteristics as well as the histopathological, immunohistochemical (IHC) and genetic data of metastasizing ileal carcinoids in three consecutive first-degree relatives. Methods: The histopathological and IHC analyses were performed on newly cut sections of the tumor specimens and included growth pattern, proliferation index (Ki67) as well as expression of established neuroendocrine markers and recently introduced cocaine-amphetamine-regulated transcript (CART). The genetic analyses were focused on establishing whether a connection with the MEN 1 syndrome existed in this family, by means of mutation screening using polymerase chain reaction, multiple ligation-dependent probe amplification, and genotyping using fluorescent-labeled microsatellite markers. Results: Histopathology and IHC revealed that the tumors were virtually identical, with only minor differences in proliferation index and expression of CART. Genetic analyses indicated that the inheritance of the small bowel carcinoids in the family was not linked to the MEN1 gene. Conclusion: Metastasizing small bowel carcinoids have been found in first-degree relatives in three consecutive generations. All three tumors were very similar when characterized by histopathology and IHC. Based on clinical findings and genetic analyses, it seems unlikely, although not completely excluded, that inheritance was linked to the MEN 1 syndrome. Copyright (c) 2010 S. Karger AG, Basel
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| 16. |
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| 20. |
- Landerholm, Kalle, et al.
(författare)
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Cocaine- and Amphetamine-Regulated Transcript in Neuroendocrine Tumors
- 2011
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 94:3, s. 228-236
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Cocaine-and amphetamine-regulated transcript (CART) is an anorexigenic regulatory peptide highly expressed in the brain's appetite control centers, but also in peripheral neurons and in endocrine cells in the adrenal medulla, thyroid, pancreatic islets, and in the gastrointestinal tract. Plasma levels of CART were recently shown to be elevated in patients with neuroendocrine tumors (NETs), but the cellular sources of CART in NETs have remained unknown. The aim of the study was to establish whether CART is expressed in various types of NETs and, if so, to examine the frequency, distribution and phenotype of CART-expressing cells. Methods: Tumor specimens from 133 NETs originating in the stomach, ileum, rectum, pancreas and thyroid were examined with immunohistochemistry and in situ hybridization. The expression of CART was quantified and the CART-expressing cells were phenotyped by double staining for established markers and hormones. Results: CART-expressing tumor cells were found in the majority of the examined NETs. The expression pattern of CART was highly heterogeneous not only between tumors, but also within individual tumors. In 14% of the NETs, CART was found in a major population of the tumor cells. Conclusion: CART is produced in the majority of NETs, regardless of tumor origin. This likely explains the elevated levels of circulating CART in certain NETs patients, as recently described. CART could therefore prove to be a useful tool in the diagnostics of NETs not only in blood samples, but also in histopathological specimens. Copyright (C) 2011 S. Karger AG, Basel
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