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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 210 (2000), S. 120-128 
    ISSN: 1432-041X
    Keywords: Key words Key words: Wing-deficient mutant fl ; Bombyx mori ; Wing imaginal discs ; Ecdysteroid ; Metamorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The wing-deficient mutant, flügellos (fl), of the silkworm, lacks four wings in the pupa and the adult. Previous studies have suggested that the fl wing discs lose responsiveness to ecdysteroid during metamorphosis. To test this hypothesis at the molecular level we compared the expression of 12 genes when the wing discs from the wild-type (WT) and fl larvae were cultured in the presence or absence of 20-hydroxyecdysone (20E). Most of the genes tested here, ecdysteroid-inducible (EcR-A, -B1,and E75) and noninducible genes (actin A3, β-tubulin, apterous (ap), USP, and BHR38) were normally expressed in the fl wing discs. However, the amounts of mRNAs of two ecdysteroid-inducible genes, BHR3 (early-late gene; Bombyx homologue to DHR3 and MHR3) and Urbain (wing-specific late gene), were reduced to about 50% and 20% of WT in the cultured fl wing discs, respectively. We analyzed developmental profiles of these mRNAs during metamorphosis. They also demonstrated decreased BHR3 and Urbain mRNA 2 days after the onset of wandering. This reduction in transcription of BHR3 in the fl mutant was observed only in the wing disc, not in the testis and fatbody. These results imply that the aberrant expression of the fl gene affects the downstream pathway of ecdysteroid signaling specifically in the wing discs and thus leads to a deficiency in wing formation.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Keywords Gene expression regulation, transcription factors, glycosylation, homeodomain protein, oxidative stress.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. Chronic hyperglycaemia in patients with Type II (non-insulin-dependent) diabetes mellitus often leads to a decline in glucose-responsive insulin secretion from pancreatic beta cells, a phenomenon called glucose toxicity. Upon hyperglycaemia, glycation reaction occurs in the beta cells and induces oxidative stress. To understand the molecular basis of the beta-cell glucose toxicity, we investigated the possible effects of glycation on the expression and enzymatic activity of glucokinase, which plays a crucial part in glucose-responsive insulin secretion.¶Methods. Glycation and reactive oxygen species were induced in HIT-T15 cells by treatment with d-ribose and effects on glucokinase gene transcription, glucokinase protein amount, glucose phosphorylation activity, and DNA-binding activities of putative glucokinase gene transcription factors were evaluated.¶Results. When glycation was induced in HIT-T15 cells, the activity of the human glucokinase gene beta-cell-type promoter was suppressed substantially (83 % reduction at 60 mmol/l d-ribose). Also, similar reductions in mRNA and protein amounts of glucokinase and in the Vmax of its enzymatic activity were observed. In agreement with the reduction in the promoter activity, the two major transcription factors of the glucokinase gene, the Pal-binding factor and PDX-1, reduced their binding to their target sequences in the glucokinase gene promoter in glycation-induced HIT cells. Because these effects of d-ribose were counteracted by aminoguanidine or N-acetylcysteine, reactive oxygen species, generated by the glycation reaction, appears to be involved in the phenomena.¶Conclusion/interpretation. The induction of the glycation reaction, which is known to occur in pancreatic beta cells in chronic hyperglycaemia, suppresses the glucokinase gene transcription and its enzymatic activity. Thus, hyperglycaemia-dependent inhibition of glucokinase activity could in part explain beta-cell glucose toxicity. [Diabetologia (1999) 42: 1417–1424]
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Keywords Oxidative stress ; glucose toxicity ; p21 ; cyclin-dependent kinase ; insulin gene ; insulin secretion ; beta-cell.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Aims/hypothesis. Prolonged poor glycaemic control in patients with Type II (non-insulin-dependent) diabetes mellitus often causes pancreatic beta-cell dysfunction accompanied by decreases in insulin biosynthesis and beta-cell proliferation. This is well known as a clinical concept called glucose toxicity. Whereas oxidative stress is provoked under diabetic conditions, we examined the possible implication of cyclin-dependent kinase (Cdk) inhibitor p21 (WAF1/CIP1/Sdi1) in beta-cell dysfunction mediated by oxidative stress. Methods. Oxidative stress was induced in isolated rat pancreatic islet cells by treatment with H2O2 and mRNA expression of p21 and insulin was examined by northern blot analyses. Also, the expression of p21 and insulin mRNA was examined in Zucker diabetic fatty rat. In islet cells p21 was overexpressed using adenovirus and its effect on insulin gene transcription was examined. Results. When oxidative stress was charged on isolated rat pancreatic islet cells, p21 mRNA expression was induced whereas insulin mRNA was decreased. Also, when diabetes developed in Zucker diabetic fatty rats, p21 expression was induced and the insulin mRNA expression was reduced. As support for the implication of p21 in impairment of beta-cell function, the p21 overexpression in the islet cells suppressed the insulin gene transcription. Conclusions/interpretation. The expression of cyclin-dependent kinase inhibitor p21, which can be induced by oxidative stress, increases in pancreatic islet cells upon development of diabetes. By suppressing cell proliferation and insulin biosynthesis, the p21 induction is likely to be implicated in the beta-cell glucose toxicity. [Diabetologia (1999) 42: 1093–1097}
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Mitochondrial encephalomyopathy ; Myoclonus epilepsy with ragged-red fibers (MERRF) ; Strongly succinate dehydrogenase-reactive blood vessels (SSV) ; Cytochrome c oxidase (CCO) ; Vascular involvement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary More than half of the intramuscular blood vessels in muscle biopsies from five patients with myoclonus epilepsy with ragged-fibers (MERRF) who had a point mutation in mitochondrial DNA at the tRNALys region were darkly stained with succinate dehydrogenase (SDH) stain, showing the morphologic characteristics of strongly SDH-reactive blood vessels (SSV), but they had no cytochrome c oxidase (CCO) activity. By electron cytochemistry, the mitochondria in the smooth muscle cells of SSV had no CCO activity. On the other hand, SSV in muscle biopsies from patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) had normal CCO activity as shown by light and electron microscopy. The defect in CCO activity in the arteriolar smooth muscle cells and in muscle fibers suggests that CCO deficiency is related to the pathophysiology of MERRF.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0509
    Keywords: Key words: Liver, blood supply—Ultrasound (US), Doppler studies.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Background: Aberrant gastric venous drainage (AGVD) into the posterior edge of the medial segment of the liver (segment IV) is the main cause of pseudolesion on computed tomography (CT) during arterial portography. We estimated the prevalence of AGVD into the medial segment of the liver with color and power Doppler ultrasound (US). Methods: Screening gray-scale and color Doppler and power Doppler US were performed in 100 consecutive patients. AGVD was defined as a venous structure that ascended parallel to the main portal vein and drained independently into segment IV. Results: AGVDs were observed in eight of 100 patients (8%) with color and power Doppler US. Power Doppler US depicted these veins more clearly than did color Doppler US. Gray-scale US did not show any AGVDs. Two of eight patients with AGVDs detected by color Doppler US underwent celiac arteriography and CT during arterial portography (CTAP). In these two patients, celiac arteriography directly demonstrated AGVDs draining into segment IV, which revealed nontumorous perfusion defects (pseudolesions) on CTAP. Conclusion: Color and power Doppler US are useful imaging methods for demonstrating AGVDs.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 3 (1964), S. 297-308 
    ISSN: 1432-0533
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Neuropathological and histochemical observations on 3 cases of Gaucher's disease are reported. Clinically they were characterized as earliest infantile type (1st case), as infantile type (Säuglings-Gaucher, 2nd case) and as juvenile type (3rd case). In the pathological-anatomical respect these cases represented the definite picture of Morbus Gaucher. Vascular changes were present in the cerebrum in every case. The two infantile cases showed adventitial proliferation with giant cells, corresponding to Gaucher-cells. Only a small number of giant cells were present in the third juvenile case, whereas a striking proliferation of adventitial cell of fibrous type was observed. The manifested parenchymal changes are as follows: Most severe damage of nerve cells, accompanied by neuronophagias and degeneration of nerve fibres was found in the dentatum (1st and 2nd case). Moreover there was disseminated loss of nerve cells with neuronophagias in the 3rd and 4th cortical layers, in the hippocampus, thalamus, opticus, nucl. ruber, substantia nigra and nuclei of the cranial nerves. “Storage-cells” were predominantly found in the hippocampus, thalamus opticus, substantia nigra etc. Histochemical examination of the cytoplasmic inclusions did'nt succeed in determining the chemical nature of the stored material. Proliferation of astrocytes within the 4th layer of the cerebral cortex was proved by silver impregnation. The pathogenesis of the parenchymal damages, however remains unsolved. There could be a relationship to the disturbance of the lipid metabolism in Morbus Gaucher; clarification of this problem by the usual histochemical methods is however not possible.
    Notes: Zusammenfassung Drei Fälle von Gaucherscher Krankheit mit neuropathologischen und histochemischen Befunden werden vorgebracht. Nach den klinischen Daten sind sie als früheste infantile Form (Fall 1), als infantile Form (Säuglings-Gaucher; Fall 2) und als juvenile Form (Fall 3) zu betrachten. Pathologisch-anatomisch bestand an der Diagnose Morbus Gaucher kein Zweifel. Neuropathologisch lagen in jedem Fall Gefäßveränderungen vor: In den beiden infantilen Fällen fanden sich Adventitiazellproliferation mit Riesenzellen, die Gaucher-Zellen entsprachen, im 3., juvenilen Fall fanden sich nur wenige Riesenzellen, dagegen eine starke Wucherung der Adventitiazellen von fibrösem Charakter. An Parenchymveränderungen fanden sich schwerste Parenchymschäden mit Neuronophagien und Faserdegeneration im Dentatum bei den beiden ersten Fällen. Ansonsten vereinzelt Zelluntergang mit Neurophagie in der 3. und 4. Schicht der Großhirnrinde, im Hippocampus, Thalamus opticus, Nucleus ruber, in der Substantia nigra und in den Hirnnervenkernen. Speicherzellen wurden an den vom Prozeß bevorzugten Stellen des ZNS, so im Hippocampus, im Thalamus und in der Substantia nigra gefunden. Die histochemischen Untersuchungen der Nervenzellblähungen ergaben keine sichere Auskunft über die chemische Natur der Protoplasmaeinlagerungen. In der 4. Schicht der Großhirnrinde erwies die Silberimprägnation eine Astrocytenproliferation. Die Pathogenese der nervösen Parenchymschädigung ist noch unklar; sie kann im Zusammenhang mit den Lipoidstoffwechselstörungen des Morbus Gaucher stehen, ist aber durch die üblichen histochemischen Methoden nicht näher aufklärbar.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1084
    Keywords: Key words: Esophageal varices ; CT ; Endoscopic variceal ligation ; MPR ; 3D image
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of this study was to demonstrate the utility of helical CT in assessing the therapeutic effects of endoscopic variceal ligation (EVL). Twenty-four patients with esophageal varices were examined. Helical scanning was initiated 60 s after intravenous injection (Iopamidol 300 mgI/ml, total 120 ml, 3 ml/s) was started. Esophageal varices were clearly depicted as high-density areas. Multiplanar reformation and 3D images demonstrated collateral circulation three-dimensionally. After EVL, mucosal high-density areas had diminished markedly, but collateral veins around the esophagus, and gastro- and/or spleno-renal shunts, were unchanged in all patients. Of 21 patients with collateral circulation, esophageal varices recurred endoscopically in 6 patients within 12 months. In 3 patients without collateral circulation, esophageal varices did not recur within 12 months. From these findings, we conclude that helical CT is a useful method for assessing the therapeutic effects of EVL.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 48 (1995), S. 61-63 
    ISSN: 1432-1041
    Keywords: Valproate ; Phenytoin ; drug interaction ; slow-release tablet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Changes in phenytoin concentrations caused by switching valproate formulations with different absorption rates were retrospectively investigated in eleven epileptic patients receiving treatment with both drugs. Total plasma phenytoin concentrations were measured before and after a standard tablet of valproate was replaced by the same dose as a slow-release tablet. The mean plasma phenytoin level rose significantly from 14.4 to 18.7 μg·ml−1. Nine of eleven patients had markedly increased phenytoin levels (by 21 to 72%), and two developed toxic symptoms. The results indicate that changing valproate formulations can cause major alterations in the plasma concentration of co-administered phenytoin.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 556-557 (Sept. 2007), p. 869-872 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: We have investigated the field limiting ring (FLR) geometry dependence of breakdownvoltage characteristics for a junction barrier Schottky (JBS)-assisted FLR SiC-SBD. The SiC-SBDshaving a guard ring-assisted FLR surrounding a Schottky contact edge and an internal ring insideSchottky contact were fabricated. The breakdown voltage characteristics of the JBS-assisted FLRSiC-SBD are significantly dependent on the width, spacing, and number of FLR. The breakdownvoltage characteristic is improved as either the FLR width and FLR number increase or the FLRspacing decreases. Approximately 1650 V maximal breakdown voltage, corresponding to 82% idealbreakdown voltage, is observed with seven FLRs having 5 2m width and 1 2m spacing
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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