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  • 1
    Digitale Medien
    Digitale Medien
    Melbourne, Australia : Blackwell Science Pty
    Clinical and experimental pharmacology and physiology 28 (2001), S. 0 
    ISSN: 1440-1681
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: 1. A new method was developed for non-invasive investigations of intracellular pH (pHi) regulation in different cell types of the isolated perfused pancreas using a confocal laser scanning technique.2. After removal of the rat pancreas the coeliac artery was cannulated and the splenic segment of the pancreas was perfused with dextran (5%)–Ringer solution at a constant flow rate of 2 mL/min. In a temperature-controlled (37°C) chamber, pH regulation was studied using the pH-sensitive fluorescent dye 2′,7′-bis-(2-carboxyethyl)-5-(-6)-carboxyfluorescein (BCECF) with a confocal microscope (MRC-600; Bio-Rad, Hercules, CA, USA).3. Image analysis permitted the identification and comparison of different cell types with a pHi of 7.26±0.1 in acinar cells and of 7.02±0.1 in endothelial cells. Increasing PCO2 from 5 to 20% resulted in a rapid decrease in pHi. Omission of sodium from the perfusate resulted in a smooth decline in pHi. Both decreases were found to be fully reversible. Increasing PCO2 under sodium-free conditions also resulted in a drop of pHi that was, however, not fully reversible, suggesting involvement of the Na+/H+ exchanger in the regulation of pHi in the intact organ.4. The above method completely preserves tissue integrity and, therefore, allows the study of pH regulation in different cell types of the pancreas simultaneously and without interference with their functional arrangement. The technique should be of specific value to investigate experimental disease states of the pancreas.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Naturwissenschaften 56 (1969), S. 372-372 
    ISSN: 1432-1904
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1432-119X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  The sensitivity and practicability of in situ hybridization methods utilizing isotopic or non-radioactive labeling were compared. The aim of this study was to determine whether digoxigenin-labeled riboprobes are as sensitive as 35S-labeled probes to detect changes in type I and IV procollagen expression in an animal model of rat gastric ulcer. Both labeling and detection methods yielded similar results, with a superimposable signal distribution in the specimens. High levels of procollagen type I and IV transcripts were observed in spindle-shaped cells, presumably fibroblasts or myofibroblasts, localized in the ulcer base and rim. The increased expression of these collagen types suggests a remarkable upregulation of collagen expression during the healing of gastric ulcers. Liver tissue adhering to perforated ulcers displayed signals related to non-parenchymal cells, with hepatocytes demonstrating no detectable transcripts of type I or IV collagen genes. Due to the identical pattern of signal distribution by both hybridization techniques it is concluded that non-radioactive in situ hybridization is of value in monitoring highly expressed genes and yields results similar to those achieved with radioactive probes. In these cases, non-radioactive techniques are preferable because they are performed more rapidly and do not require handling of isotopes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1432-119X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The sensitivity and practicability of in situ hybridization methods utilizing isotopic or non-radioactive labeling were compared. The aim of this study was to determine whether digoxigenin-labeled riboprobes are as sensitive as35S-labeled probes to detect changes in type I and IV procollagen expression in an animal model of rat gastric ulcer. Both labeling and detection methods yielded similar results, with a superimposable signal distribution in the specimens. High levels of procollagen type I and IV transcripts were observed in spindle-shaped cells, presumably fibroblasts or myofibroblasts, localized in the ulcer base and rim. The increased expression of these collagen types suggests a remarkable upregulation of collagen expression during the healing of gastric ulcers. Liver tissue adhering to perforated ulcers displayed signals related to non-parenchymal cells, with hepatocytes demonstrating no detectable transcripts of type I or IV collagen genes. Due to the identical pattern of signal distribution by both hybridization techniques it is concluded that non-radioactive in situ hybridization is of value in monitoring highly expressed genes and yields results similar to those achieved with radioactive probes. In these cases, non-radioactive techniques are preferable because they are performed more rapidly and do not require handling of isotopes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular medicine 53 (1975), S. 841-846 
    ISSN: 1432-1440
    Schlagwort(e): Cyclic adenosine 3′:5′-monophosphate ; gastric acid secretion ; “second messenger” concept ; species dependence ; Cyclisches Adenosin-3′:5′-monophosphat ; gastrale Säuresekretion. „second messenger“-Konzept ; Speciesabhängigkeit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Ob bei einer bestimmten Hormonwirkung cyclisches Adenosin-3′:5′-monophosphat (cAMP) als intracellulärer Vermittler fungiert, läßt sich nach den von Sutherland entwickelten Kriterien beurteilen; dabei sind die qualitativen, quantitativen und zeitlichen Beziehungen zwischen dem Hormoneffekt auf den intracellulären cAMP-Spiegel und die jeweilige physiologische Antwort zu prüfen. Im Falle der Histamin- bzw. Pentagastrin-stimulierten gastralen Säuresekretion des Frosches (Necturus maculosus) und der Ratte erfüllt das cAMP die Bedingungen eines „second messenger“. Dagegen ließ sich beim Hund und Menschen eine derartige Funktion des cAMP bisher nicht verifizieren; ob bei diesen Species cyclisches Guanosin-3′:5′-monophosphat anstelle des cAMP die intracelluläre Vermittlerrolle übernimmt, werden erst noch systematische Untersuchungen erweisen müssen.
    Notizen: Summary The criteria to determine whether cyclic adenosine 3′:5′-monophosphate (cyclic AMP) is or is not involved in a particular hormone response require to look for positive qualitative, quantitative and temporal correlations between the effects of the hormone on cyclic AMP levels and the physiological response. These requirements have been shown to be fulfilled in histamine and pentagastrinstimulated gastric acid secretion of the frog (Necturus maculosus) and the rat. In dog and man, however, the available evidence does not support a role for cyclic AMP in the gastric secretory process; it remains a challenge for future research whether in those species cyclic guanosine 3′:5′-monophosphate acts as an intracellular substitute for cyclic AMP.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 22 (1977), S. 454-461 
    ISSN: 1573-2568
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Conclusion Motilin is found in the enterochromaffin cells of the human intestine. It can be released by duodenal acidification or fat intake. Motilin effects appear to be confined exclusively to the gastrointestinal tract. Before, however, hormonal status can be assigned to a candidate hormone, “it must be shown that the peptide in question is released in amount and kind sufficient to account for the physiologic event under consideration” (81). Synthetic motilin is capable of increasing lower esophageal sphincter pressure and gastric pepsin secretion while it decreases gastric mucosal protein biosynthesis and inhibits gastric emptying. These effects can be achieved by exogenous motilin infusions at doses that produce plasma motilin levels comparable to those after endogenous motilin release. So, motilin has taken first steps out of the candidate hormone reserve towards the respectability of recognition as a gastrointestinal hormone.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0878
    Schlagwort(e): Key words: Collagen ; Combined non-radioactive in-situ hybridization and immunohistochemistry ; Gastric ulcer ; Immunohistochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. The restoration of gastric tissue after ulceration involves cellular and matrix components. Our aim was to investigate the kinetics of collagen expression and cellular proliferation in an animal model of gastric ulcer. To demonstrate the expression of type I and IV collagen mRNAs by proliferating cells, a method combining in-situ hybridization and immunohistochemistry was devised. In order to avoid the disadvantages of radioisotopes, digoxigenin-labeled RNA-riboprobes were utilized and combined with single-step immunohistochemistry. This method proved sensitive enough to detect type I and IV procollagen mRNA transcripts in the submucosal area beneath the ulcer crater or adjacent to the ulcer rim. In addition, a subset of cells transcribing either procollagen type I or IV RNA was concomitantly positive for proliferating cell nuclear antigen by immunohistochemistry. Focal proliferation of cells simultaneously expressing extracellular matrix components may therefore occur in the gastric submucosa after ulceration, starting as soon as 3 days after the insult and continuing for several weeks. The devised method of combined in-situ hybridization and immunohistochemistry can be used with standard paraffin-embedded tissues, yields results within 2 days, and avoids radioisotopes.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    ISSN: 1573-904X
    Schlagwort(e): chitosan microspheres ; HT-29B6 cell monolayers ; small intestine ; prednisolone sodium phosphate ; drug absorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Purpose. The present study was performed to investigate the influence of chitosan microspheres on transport of the hydrophilic, antiinflammatory drug prednisolone sodium phosphate (PSP) across the epithelial barrier. Methods. Microspheres were prepared using a precipitation method and loaded with PSP. Transport studies were performed in a diffusion cell chamber using the polarized human cell line HT-29B6. Porcine small intestine and fluorescence-labeled microspheres were used to investigate penetration ability of microspheres. Results. It was shown that transport of PSP drug solution was not saturable across the cell monolayers (P = 8.68 ± 8.24 × 10−6 cm sec−1) and no sodium dependency could be established. EGTA treatment resulted in an increased permeability (P = 18.69 ± 1.09 × 10−6 cm sec−1). After binding of prednisolone to chitosan microspheres its permeability was enhanced drastically compared with the drug solution (P = 35.37 ± 3.21 ×10−6 cm sec−1). This effect was prevented by EGTA treatment (P = 15.11 ± 2.57 × 10−6 cm sec−1). Furthermore the supporting effect of chitosan microspheres was impaired by pH and ion composition of the medium, whereas the effect remained unchanged in cells treated with bacterial lipopolysaccharides. In vitro incubation of fluorescence-labeled microspheres in the lumen of freshly excised intestine revealed a significant amount of the spheres in the submucosa. Conclusions. Chitosan microspheres are a useful tool to improve the uptake of hydrophilic substances like PSP across epithelial layers. The effect is dependent on the integrity of the intercellular cell contact zones and the microparticles are able to pass the epithelial layer. Their potential benefit under inflammatory conditions like in inflammatory bowel disease, in order to establish high drug doses at the region of interest, remains to be shown.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1573-2568
    Schlagwort(e): LYSOSOMAL ENZYMES ; COMBINED TREATMENT ; Th-2 CYTOKINES ; MONOCYTES ; INFLAMMATORY BOWEL DISEASE
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Tissue injury and inflammation in inflammatorybowel disease (IBD) are associated with enhancedmonocytic lysosomal enzyme release. In this study,peripheral monocytes and lamina propria mononuclearcells (LPMNC) were isolated from IBD patients andnormal controls. Cells were stimulated withlipopolysaccharide after treatment with IL-13, IL-4, andIL-10, and enzyme secretion was assessed by using thecorresponding p-nitrophenyl glycosides as substrates.Molecular forms of cathepsin D were examined to describethe mode of enzyme release. IL-10 and IL-4 stronglydown-regulate enzyme secretion in IBD monocytes. IBD monocytes showed a diminished responsiveness tothe inhibitory effect of IL-13. Impaired monocyteresponse was not found with combinations of IL-13 andIL-10 or IL-4 and IL-10. LPMNC from involved IBD mucosa showed significantly higher enzyme secretioncompared with LPMNC from noninvolved IBD mucosa butresponded inefficiently to either IL-4, IL-13, or IL-10alone. However, combined treatment with IL-10 and IL-4 or IL-10 and IL-13 strongly suppressedenzyme release by these cells. Both the precursor andmature forms of cathepsin D were elevated in IBDpatients. While IL-13 reduced mainly the precursor form, the effect of IL-4 and IL-10 concerns both theprecursor and mature form of cathepsin D. Our resultsfavor the potent clinical utility of combined treatment,thus improving chances of developing effective treatments for human IBD.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 1573-2568
    Schlagwort(e): INTESTINAL EPITHELIAL CELLS ; INTERLEUKIN-8 ; TH-2 CYTOKINES
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Intestinal epithelial cells are able to producesoluble mediators that initiate or amplify inflammatoryevents in the intestinal mucosa. Interleukin (IL)-8 issuggested to be a cytokine playing a major role during the acute and chronic processes ininflammatory bowel disease (IBD). TH-2 cytokines havebeen described as down-regulating the inflammatoryresponse. We analyzed the effects of IL-10, IL-13, and IL-4 on IL-8 secretion in intestinalepithelial cells. The human colonic epithelial cell lineCaco-2 and freshly isolated intestinal epithelial cellswere used. Cells weRestimulated with IL-1beta after treatment with TH-2 cytokines. Levels of IL-8were determined by employing enzyme-linked immunosorbentassay (ELISA). Stimulation with IL-1beta results in atime-dependent IL-8 secretion. The addition of IL-4 and IL-13, but not IL-10, to activatedepithelial cells resulted in a strong decrease in IL-8secretion. Maximal inhibition required that TH-2cytokines be added up to 60 min before or simultaneous with stimulatory agents. We present novelfindings that IL-4 and IL-13 strongly down-regulate IL-8secretion from intestinal epithelial cells. Amicroenvironment containing high concentrations of IL-4and IL-13 may alter The recruitment of immune cellsto enterocytes at least partly by inhibiting IL-8production. This inhibition might diminish the severityof the intestinal inflammatory response and, thus reduce clinical disease activity.
    Materialart: Digitale Medien
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