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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.

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.

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.

Secretagogin is a recently cloned human beta-cell-expressed EF-hand Ca(2+)-binding protein. Converging evidence indicates that it exerts Ca(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 after 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(2+) sensitivity of dexamethasone-treated insulin-secreting cells.

Expression of the small heat shock protein alphaB-crystallin in differentiated thyroid tumors has been described recently. In this study, we investigated the molecular mechanisms that affect the expression of alphaB-crystallin in benign goiters (n = 7) and highly malignant anaplastic thyroid carcinomas (ATCs) (n = 3). AlphaB-crystallin expression was compared with that of Hsp27-1. Immunoblot and quantitative real-time (RT) polymerase chain reaction revealed marked downregulation of alphaB-crystallin in all the tested ATCs and the ATC-derived cell line C-643 . In contrast, considerable expression of Hsp27-1 in benign and malignant thyroid tissue was demonstrated. Immunofluorescence analysis revealed no relevant topological differences between benign and malignant thyrocytes in the cytoplasmic staining of both proteins. Consistent and marked downregulation of TFCP2L1 was identified as one of the main mechanisms contributing to CRYAB gene silencing in ATCs. In addition, CRYAB gene promoter methylation seems to occur in distinct ATCs. In silico analysis revealed that the differential expression of alphaB-crystallin and Hsp27-1 results from differences between the alphaB-crystallin and Hsp27-1 promoter fragments (712 bp upstream from the transcriptional start site). Biological activity of the analyzed promoter element is confirmed by its heat shock inducibility. In conclusion, we demonstrate downregulation of alphaB-crystallin expression in highly dedifferentiated ATCs because of a tumor-specific transcription factor pattern. The differential expression of alphaB-crystallin and Hsp27-1 indicates functional differences between both proteins.

Multiple RET proto-oncogene transcripts, due to genomic variations and alternate splicing, have been described. To investigate endocrine tumor tissue characteristic RET proto-oncogene expression, we performed quantitative RT-PCR, Northern blot and Southern blot analyses of benign and malignant endocrine-derived tissues. We newly describe RET proto-oncogene expression in carcinoid-, gastrinoma- and insulinoma-derived tissue samples. In addition, the presence of a 3'-terminally truncated RET proto-oncogene mRNA variant in benign and malignant thyroid neoplasias, as well as in a pheochromocytoma, an ovarian carcinoma and a medullary thyroid carcinoma, is demonstrated. Southern blot analysis revealed no evidence of gross RET proto-oncogene rearrangements or deletions. As the underlying cause for a bi-allelic TaqI restriction fragment length polymorphism (RFLP), a C (allele 1)/T (allele 2) transition within intron 19, was characterized. This polymorphism is close to a recently described polyadenylation site and lies within a binding site for the nucleic acid binding protein Pbx-1. Screening of healthy subjects and of patients suffering from various endocrine malignancies revealed exclusively allele 1 homozygous and allele 1/allele 2 heterozygous genotypes. Heterozygous genotypes were found in a significantly higher percentage in samples derived from endocrine tumor patients when compared with those from healthy control subjects. Homozygosity for allele 2 was found exclusively in somatic DNA derived from endocrine tumors with high malignant potential. Analysis of DNA derived from varying regions within individual anaplastic thyroid carcinomas revealed an allele 1/allele 2 switch of the RFLP banding pattern, indicating loss of heterozygosity at the RET proto-oncogene locus. In conclusion, our data demonstrate presence of a 5'-terminal RET proto-oncogene transcript in endocrine tissues and reveal a bi-allelic RET proto-oncogene polymorphism. A heterozygous genotype for this polymorphism is found in a considerable number of endocrine tumor patients.

We have cloned a novel pancreatic beta cell and neuroendocrine cell-specific calcium-binding protein termed secretagogin. The cDNA obtained by immunoscreening a human pancreatic cDNA library using the recently described murine monoclonal antibody D24 contains an open reading frame of 828 base pairs. This codes for a cytoplasmic protein with six putative EF finger hand calcium-binding motifs. The gene could be localized to chromosome 6 by alignment with GenBank genomic sequence data. Northern blot analysis demonstrated abundant expression of this protein in the pancreas and to a lesser extent in the thyroid, adrenal medulla, and cortex. In addition it was expressed in scant quantity in the gastrointestinal tract (stomach, small intestine, and colon). Thyroid tissue expression of secretagogin was restricted to C-cells. Using a sandwich capture enzyme-linked immunosorbent assay with a detection limit of 6.5 pg/ml, considerable amounts of constitutively secreted protein could be measured in tissue culture supernatants of stably transfected RIN-5F and dog insulinoma (INS-H1) cell clones; however, in stably transfected Jurkat cells, the protein was only secreted upon CD3 stimulation. Functional analysis of transfected cell lines expressing secretagogin revealed an influence on calcium flux and cell proliferation. In RIN-5F cells, the antiproliferative effect is possibly due to secretagogin-triggered down-regulation of substance P transcription.

The G-protein-coupled receptor rhodopsin is activated by photoconversion of its covalently bound ligand 11-cis-retinal to the agonist all-trans-retinal. After light-induced isomerization and early photointermediates, the receptor reaches a G-protein-dependent equilibrium between active and inactive conformations distinguished by the protonation of key opsin residues. In this report, we study the role of the 9-methyl group of retinal, one of the crucial steric determinants of light activation. We find that when this group is removed, the protonation equilibrium is strongly shifted to the inactive conformation. The residually formed active species is very similar to the active form of normal rhodopsin, metarhodopsin II. It has a deprotonated Schiff base, binds to the retinal G-protein transducin, and is favored at acidic pH. Our data show that the normal proton transfer reactions are inhibited in 9-demethyl rhodopsin but are still mandatory for receptor activation. We propose that retinal and its 9-methyl group act as a scaffold for opsin to adjust key proton donor and acceptor side chains for the proton transfer reactions that stabilize the active conformation. The mechanism may also be applicable to related receptors and may thus explain the partial agonism of certain ligands.