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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Molecular and cellular biochemistry 178 (1998), S. 169-179 
    ISSN: 1573-4919
    Schlagwort(e): reactive oxygen species (ROS) ; calcium (Ca2+) ; protein kinase C (PKC) ; prostaglandins (PGs) ; superoxide dismutase ; catalase ; glutathione peroxidase ; reduced glutathione
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract To evaluate the role of reactive oxygen species (ROS) in Shigella dysenteriae 1 toxin (STx) mediated intestinal infection, the ligated rabbit small intestinal loops were injected with STx. The enterocytes isolated from STx treated rabbit ileal loops had a significantly higher level of lipid peroxidation as compared to enterocytes isolated from control rabbit ileum. To study the role of second messengers in STx mediated intestinal damage, the in vivo and in vitro effects of modulators of lipid peroxidation of enterocytes were used. The presence of Ca2+-ionophore A23187 enhanced the extent of lipid peroxidation in enterocytes isolated from the control and STx treated rabbit ileum. However, l-verapamil only marginally decreased the lipid peroxidation level of enterocytes isolated from STx treated rabbit ileum. The in vitro effect of modulators was in agreement with in vivo studies. Dantrolene significantly decreased the extent of lipid peroxidation of enterocytes isolated from STx treated rabbit ileum. PMA significantly increased the lipid peroxidation level of enterocytes isolated from control ileum. However, PMA could not further enhance the lipid peroxidation level of enterocytes isolated from STx treated rabbit ileum. The presence of H-7 significantly decreased the extent of lipid peroxidation of enterocytes isolated from STx treated rabbit ileum. In vitro effect of PMA and H-7 was in agreement with that of in vivo findings. The role of arachidonic acid metabolites, prostaglandins (PGs), in mediating STx induced lipid peroxidation was also studied. The presence of indomethacin (a PG synthesis inhibitor) significantly decreased the lipid peroxidation induced by STx. These findings suggest that lipid peroxidation induced by STx is mediated through cytosolic calcium. The increase in (Ca2+)i leads to activation of PKC. A significant decrease in the enterocyte levels of antioxidant enzymes superoxide dismutase, catalase and reduced glutathione in STx treated rabbit ileum as compared to control was seen. A significant decrease in vitamin E levels was also observed. This suggests that there is decreased endogenous intestinal protection against ROS in STx mediated intestinal infection which could contribute to enterocyte membrane damage that ultimately leads to changes in membrane permeability and thus to fluid secretion.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Molecular and cellular biochemistry 196 (1999), S. 175-181 
    ISSN: 1573-4919
    Schlagwort(e): enterotocin ; lipid peroxidation ; Salmonella typhimurium ; oxygen free radicals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract Reactive oxygen species (ROS) are potent mediators of inflammatory disorders and may be of pathophysiological importance in S. typhimurium induced tissue damage. This study was carried out to investigate if ROS play a role in mediating the enterocyte damage during in vitro exposure to Salmonella typhimurium enterotoxin (S-LT). The ROS generation was detected by measuring the changes in the enterocyte arachidonic acid (AA) metabolism (measured indirectly by estimating the level of enterocyte damage in the absence and presence of the cyclooxygenase inhibitor, indomethacin) and xanthine oxidase activity. The enterocyte damage was estimated by measuring the changes in the level of lipid peroxidation and cell viability. The results obtained showed that the exposure of isolated rat enterocytes to S-LT resulted in an increased XO activity; an increased arachidonic acid metabolism, dose and time dependent increase in the level of lipid peroxidation and decreased cell viability. Lipid peroxidation decreased and cell viability increased in the presence of the antioxidant enzymes superoxide dismutase (SOD) or catalase. Thus the in vitro exposure of the enterocytes to S-LT is accompanied by an increased generation of ROS which may induce the lipid peroxidation of the enterocyte membrane thereby leading to a loss of cell viability.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Bioscience reports 6 (1986), S. 633-638 
    ISSN: 1573-4935
    Schlagwort(e): muscle cDNA ; cDNA library ; fetal tissues ; Northern blots ; sequencing ; β-myosin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Human fetal muscle cDNA library was screened with aβ-myosin heavy chain gene fragment containing Alu sequences. Two cDNA clones AI and BII with 1.8 and 3 kb inserts respectively were chosen for further characterization by means of RNA and DNA hybridization procedures and sequencing. The clones appeared to contain repetitive sequences as well as single copy regions. They are actively transcribed in different stages of myogenic development but not in the liver. DNA sequence analysis of short stretches from both clones revealed no sequence homology to any other published DNA sequences.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 43 (1998), S. 646-651 
    ISSN: 1573-2568
    Schlagwort(e): ANTIOXIDANTS ; INTESTINE ; SALMONELLA TYPHIMURIUM GLUTATHIONE
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The mucosal pathology of Salmonella typhimuriuminfection may in part be due to the excessive productionof reactive oxygen species (ROS). The influence of S.typhimurium infection on the intestinal mucosal antioxidant defense system was investigated. Weinjected ligated rat ileal loops with Salmonella liveculture or toxin. After 18 hr of infection, the animalswere killed and enterocytes isolated from the ileal loops. The enterocyte-reduced glutathione(GSH) content and activities of the enzymes superoxidedismutase (SOD), glutathione peroxidase (GSH-Px),catalase, glutathione-S-transferase (GST), glutathione reductase (GR), and glucose-6-phosphatedehydrogenase (G6PDH) were spectrophotometricallyestimated. The vitamin E and A contents were determinedby high-performance liquid chromatography (HPLC). Inboth the Salmonella live culture and toxin-treatedgroups, the enterocyte GSH and vitamin E contents andactivities of the enzymes SOD, GSH-Px, catalase, GR, andG6PDH were significantly decreased as compared to the control group. However there was asignificant increase in the enterocyte activity of GST.There was no change in the vitamin A content of theenterocytes. These findings might indicate a decreased endogenous intestinal protection against ROS inS. typhimurium-mediated infection, which couldcontribute to the pathogenesis of the disease.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 36 (1989), S. 105-118 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The effect of molecular interaction on the O—H stretching force constant of methanol (MeOH) is reported for its associated species. The various electron donors (D) and acceptors (A) considered include organic molecules such as methanol, dimethylether, acetone, acetonitrile, dimethyl formamide, pyridine, and ions such as F-, Cl-, Li+, and H+. The variation in the O—H stretching force constant of MeO—H…D species on interaction with the electron acceptor such as in the species is explained on the basis of the cooperativity effect. (CE). The effect is discussed in terms of the relationship CE = (ΔF/F) × 100, where ΔF is the reduction is force constant of the hydrogen-bonded O—H stretching mode of the associated methanol species MeOH…D when the lone pair electrons on oxygen of the methanol molecule are involved in hydrogen bonding with A, and F is the hydrogen-bonded O—H stretching force constant of the species when the lone pair electrons are free. The cooperativity effect (CE) is found to increase with increasing electron acceptor and electron donor capacities of A and D. The calculated force constants are compared with the experimental results.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 55 (1995), S. 477-484 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ab initio molecular orbital (MO) calculations with the 3-21G and 6-31G basis sets are carried out on a series of complexes of NH3 with Li+, C≡N-, LiCN, and its isomer LiNC. The BSSE-corrected interaction energies, geometrical parameters, internal force constants, and harmonic vibrational frequencies are evaluated for 15 species. Complexes with trifurcated (C3v) structures are calculated to be saddle points on the potential energy surfaces and have one imaginary frequency each. Calculated energies, geometrical parameters, internal force constants, and harmonic vibrational frequencies of the various species considered are discussed in terms of the nature of association of LiCN with ammonia. The vibrational frequencies of the relevant complexed species are compared with the experimental frequencies reported earlier for solutions of lithium cyanide in liquid ammonia. © 1995 John Wiley & Sons, Inc.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 17
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 20 (1989), S. 169-179 
    ISSN: 0377-0486
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Raman spectra in the C—H and S=O stretching and S=O bending regions are reported for solutions of lithium halides and tetrabutylammonium bromide (TBAB) in dimethyl sulphoxide (DMSO) and DMSO-d6. The C—D stretching band of DMSO-d6 shows two components in solutions of TBAB with DMSO-d6, whereas the C—H stretching band of DMSO for solutions of LiX (X = Br and I) in DMSO show some broadening and asymmetry in the low-frequency region. The S=O stretching bands show changes in band shapes and band contours in solutions of electrolytes in DMSO. Fourier deconvolution of C—H and S=O stretching bands were carried out to gain more information regarding number of components present under the broad structured bands. All the solutions show a significant decrease in the intensity of the S=O bending bands when compared with the neighbouring C—S bending band. The results are discussed in terms of anion- and cation-molecular interactions with DMSO.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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