Vibrational Energy Of Diatomic Molecule

This work was supported by grantsfrom the European Commission; the Bundesmin isterium fur Bildung, Wissenschaf t, Forschung und Technologie; and the BiologischMedizin ische Forschungszentrum of the Heinrich Heine Un iversity, Dusseldor f, u S E C N E I C S L A C I D E M, rebmetpe Snotseugybded aonlwoD However, the link between inflammation and carcinogenesis in these disorders is obscure.Furthermore, iNOS and NO generation could be induced in vitro by inflammatory cytokines in three human cholangiocarcinoma cell lines.Our data indicate that activation of iNOS and excess production of NO in response to inflammatory cytokines cause DNA damage and inhibit DNA repair proteins.NO inactivation of DNA repair enzymes may provide a link between inflammation and the initiation, promotion, andor progression of cholangiocarcinoma.NO is often generated in inflammatory conditions due to the induction of NOS in epithelial cells by inflammatory cytokines released from adjacent mononuclear cells. NO produced in infected and inflamed tissues has been postulated to contribute to epithelial cell carcinogenesis by causing damage to DNA and proteins. Furthermore, NO can nitrosylate thiol and tyrosine residues in susceptible proteins altering their function, the role of protein nitrosylation in promoting potentially mutagenic changes in DNA has received far less attention.DNA repair proteins are vital for the prevention of potential DNA mutations resulting from oxidative damage.Several distinct DNA repair proteins, some displaying narrow substrate specificity and others characterized by a wide substrate range. The resulting abasic site can then be removed by an apurinicapyrimidic endonuclease.Repair proteins are themselves potentially vulnerable to oxidative damage from NO because of their active site sulphydryl, tyrosine, andor phenol side chains.Some DNA repair enzymes and formamidopyrimidineDNA glycosylase ribose polymerase have in their active sites zinc finger motifs that may also be inactivated by NO nitrosylation of the thiol moieties of their cysteinerich residues.Clearly, nitrosylation of these DNA repair proteins by excessive NO generation could compromise genomic stability.Based on this information, we formulated the central hypothesis that induction of NOS and subsequent NO production will result in oxidative DNA damage and inhibition of DNA repair enzymes.The costs of publication of this article were defrayed in part by the payment of page charges.Five micron tissue sections were deparaffinized twice in xylene for min each and rehydrated in ethanol followed by water and PBS.Endogenous peroxidase was blocked by immersion in hydrogen peroxide in methanol for min, and the tissue was washed twice in PBS for min each.Nonspecific binding was blocked, and the sections were permealized by. BSA in PBS buffer for min.The tissue sections were drained well and then incubated with iNOS antibody for hat room temperature and with nitrotyrosine antibody. The slides were then washed three times in. Human cholangiocarcinoma cells were harvested at a density of; cellsml.The plasmid DNA was recovered by phenolchloroform extraction and ethanol precipitation.Fluorescence intensities of linearized plasmid bands in comparison with known amounts of DNA were used to determine DNA loading.The gel was dried under vacuum and exposed to a storage screen for h.Background corrected values of the radioactivity incorporated for the damaged and undamaged plasmids were normalized for the amount of DNA.

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