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Secretagogin is a recently cloned human [beta]-cell-expressed EF-hand [Ca.sup.2+]-binding protein. Converging evidence indicates that it exerts [Ca.sup.2+] sensor activity and is involved in regulation of insulin synthesis and secretion. To obtain a potent tool for the extension of its functional analysis in rat in vitro systems, we cloned the rat homolog of human secretagogin. Using comparative sequence analysis, immunostaining, and immunoblotting, we demonstrated a high degree of sequence homology and similar tissue expression patterns of human and rat secretagogin. Highest rat secretagogin expression levels were found in pancreatic [beta]-cells. On the basis of newly generated anti-rat secretagogin antibodies, we established a rat secretagogin-specific sandwich capture ELISA and demonstrated release of secretagogin from viable Rin-5F cells. Dexamethasone treatment of Rin-5F cells resulted in an increased secretagogin release rate, which was inversely correlated with insulin secretion. In contrast, the secretagogin transcription rate was markedly reduced. This resulted in a decreased intracellular secretagogin content under the influence of dexamethasone. Sucrose gradient cell fractionation analysis of Rin-5F cells confirmed the predominant cytosolic localization of secretagogin, with only limited association of secretagogin with insulin granules. The loss of intracellular secretagogin alter dexamethasone treatment affected predominantly the insulin granule-associated secretagogin fractions. The sequence homology and the comparable tissue expression patterns of human and rat secretagogin indicate conserved intracellular functions. The effects of dexamethasone on the total secretagogin content in Rin-5F cells and on its intracellular distribution might result in an impaired [Ca.sup.2+] sensitivity of dexamethasone-treated insulin-secreting cells. EF-hand protein; insulin granules; dexamethasone; calcium sensor doi:10.1152/ajpendo.00055.2007

The design and analysis of the mechanical structure of the Nuclotron-type SIS100 magnets are studied. Results suggest that the coil support structure is suitable for better stabilization of the coil, while also offering other advantages.

Mounting evidence suggests cell cycle dysregulation is involved in the pathogenesis of Alzheimer's disease (AD) and that this failure is systemic, affecting not only neurons but also peripheral blood lymphocytes (PBLs). This study analyzed if differences in PBL proliferation activity could be used as a diagnostic biomarker for AD. CD69 and CD28 expressions on PBL T, B, and monocyte cells were measured by flow cytometry with and without mitogenic stimulation in healthy controls (HC), probable AD, and Parkinson's disease dementia (PDD) subjects. Univariate and multivariate scoring models were employed to evaluate the data relative to the clinical diagnoses. Eleven CD expression markers were significantly altered in AD subjects compared with a mixed pool of PDD and HC subjects using univariate models. Using multivariate models, seven CD expression markers were significantly altered in AD subjects compared with PDD subjects. Multivariate scoring demonstrated up to a 91% positive and 92% negative agreement with subject clinical diagnosis and had little correlation with the severity of dementia. Present findings suggest that with further development this analytical and multivariate modeling procedure could aid the current differential diagnosis of Alzheimer's disease., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Renal cell carcinomas are divided into several subgroups according to their histopathologic characteristics. The outcome, therapy responses, and the applicability of molecular-targeted therapies depend on the tumor classification and on the tumor stage. Recent advances within the biomarker research facilitated the exact classification of the molecular character of the renal tumor. For example, the calcium-binding proteins parvalbumin and S-100A1 are characteristically expressed in renal cell carcinoma subgroups. This led us to investigate the expression of the novel calcium-binding protein secretagogin in renal cell carcinomas. Tissue microarray cylinders including 94 clear-cell renal cell carcinomas, 61 non-clear-cell renal cell carcinomas (37 papillary renal cell and 24 chromophobe carcinomas), and 30 oncocytomas were analyzed by immunohistochemistry. This showed remarkable secretagogin expression in 37% of the clear-cell renal cell carcinomas. Non-clear-cell renal cell carcinomas and oncocytomas were completely negative. Consequently performed immunoblotting analyses confirmed this expression profile. Because publicly available data direct toward a formation of a hierarchical cluster of secretagogin overexpressing clear-cell renal cell carcinomas, we conducted a clinical follow-up of the patients with clear-cell renal cell carcinoma. This revealed significantly more metastasis within the secretagogin-positive clear-cell renal cell carcinoma subgroup (49% versus 28%; P < .05). In conclusion, we report on detection of the novel calcium-binding protein secretagogin within a subgroup of clear-cell renal cell carcinomas. The increased metastasis rates within the secretagogin-positive subgroup of clear-cell renal cell carcinomas direct toward a clinical impact of our findings., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Frequent concomitant manifestation of type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD) has been recently demonstrated by epidemiological studies. This might be due to functional similarities between β-cells and neurons, such as secretion on demand of highly specific molecules in a tightly controlled fashion. An additional similarity represents the age-related alteration of hyperphosphorylated tau in AD patients. Similarly, alterations have been identified in β-cells of T2DM patients. The islet amyloid polypeptide has been associated with β-cell apoptosis. As a consequence of increasing age, the accumulation of highly modified proteins together with decreased regenerative potential might lead to increasing rates of apoptosis. Moreover, reduction of β-cell replication capabilities results in reduction of β-cell mass in mammals, simultaneously with impaired glucose tolerance. The new challenge is to learn much more about age-related protein modifications. This can lead to new treatment strategies for reducing the incidence of T2DM and AD.

Neuropeptide Y (NPY) is an important hormone in appetite regulation. Although the contribution of NPY to metabolic disease has been previously demonstrated, there are only a few reports addressing NPY plasma levels under distinct diabetic conditions. In this study we evaluated NPY plasma levels in diabetes mellitus type 2 (DM2) patients with (n=34) and without (n=34) diabetic polyneuropathy (PNP) and compared these with age and gender matched healthy controls (n=34). We also analyzed NPY plasma levels in gestational diabetes mellitus (GDM) patients with age and pregnancy-week matched controls with normal glucose tolerance (NGT). NPY concentration was determined using a commercially available radioimmunoassay kit. In addition, metabolic parameters of DM2 and GDM patients were recorded. One-way ANOVA tests with appropriate post hoc corrections showed elevated levels of NPY in DM2 patients with and without PNP when compared with those of healthy controls (122.32±40.86 and 117.33±29.92 vs. 84.65±52.17 pmol/L; p<0.001, p<0.005, respectively). No significant difference was observed between diabetic patients with and without PNP. The NPY levels were similar in the GDM group and in pregnant women with NGT (74.87±14.36 vs. 84.82±51.13 pmol/L, respectively). Notably, the NPY concentration correlated positively with insulin levels in DM2 patients (R=0.35, p<0.01). Our data suggest a potential involvement of circulating NPY in DM2 pathology., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Tauopathies have been associated with Alzheimer's disease (AD), which frequently manifests together with diabetes mellitus type 2. Calcium-binding proteins such as the recently identified secretagogin (SCGN) might exert protective effects. As pancreatic beta-cells and neurons share common electrophysiological properties, we investigated the appearance of TAU (listed as MAPT in the HUGO and MGI Databases) protein at the islets of Langerhans and beta-cell-derived cell lines which highly express the neuroendocrine-specific protein SCGN. Six predominant TAU isoforms could be identified by immunoblotting, which formed TAU deposits detectable by immunofluorescence and sarkosyl-insoluble pellets. Using GST-SCGN pull-down assays, a calcium-dependent SCGN-TAU interaction was found. In this line, sucrose density gradient fractionation and differential ultracentrifugation studies of TAU and SCGN revealed co-appearance of both proteins. Co-localization of TAU and SCGN within insulinoma cells and islets of Langerhans mainly restricted to insulin-positive beta-cells was demonstrated by confocal microscopy. Motivated by these findings, we looked if SCGN overexpression could exert protective function on Rin-5F cells, which showed differences in TAU levels. Testing the vulnerability of Rin-5F clones by MTT assay, we revealed that high TAU levels going along with highest TAU aggregates could not be antagonized by high levels of SCGN protein. Our findings demonstrated for the first time the association of TAU and the calcium-binding protein SCGN and support earlier results implicating that beta-cells might represent an extra cerebral site of tauopathy.

Background: Angiopoiesis and angiopoietic growth factors are of considerable importance in the development and progression of intracranial tumours. However, knowledge of the plasma detectability of distinct angiogenic factors in patients with brain tumour is very limited. This study evaluates the plasma concentrations of the angiogenic factors angiopoietin-2 (Ang-2), vascular endothelial growth factor (VEGF) and platelet-derived growth factor BB (PDGF-BB) in patients with brain tumour., Patients and Methods: Plasma samples of 78 patients suffering from various types of intracranial tumours (glioblastoma multiforme, GBM, n = 22; astrocytoma, n = 12; meningioma, n = 16; and intracranial metastasis, n = 28) were analysed. For determination of plasma concentrations of angiogenic factor, highly specific enzyme-linked immuno sorbent assays (ELISAs) were used., Results: Ang-2 plasma concentration in GBM patients was significantly lower when compared with that in patients with meningioma and intracranial metastasis. Highest levels of VEGF concentrations were detected in plasma derived from patients suffering from meningioma. Interestingly, VEGF plasma levels depended on the number of intracranial lesions, with significantly higher concentrations in patients with 3 or more lesions when compared with those with 2 or fewer lesions. However, no correlation between the survival time of the patients and the plasma levels of the tested growth factors was obtained. Plasma levels of PDGF-BB did not differ between the individual tumour groups., Conclusion: The detectability of the angiogenic factors Ang-2 and VEGF, as well as of PDGF-BB, in the plasma of patients suffering from various types of brain tumours is described. The plasma detectability of the individual angiopoetic factors seems to depend at least partly on the tumour type as well as on tumour progression. This might be of prognostic and therapeutic relevance.