Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1389183 (autodigestion)
 317 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have investigated structural change in rat liver DNA produced by different isolation procedures and specifically compared the integrity of DNA derived by phenol extraction from isolated and purified nuclei with preparations extracted immediately from a crude liver homogenate containing intact nuclei. As indicated by stepwise elution from benzoylated DEAE-cellulose, most structural change in DNA was evident following nuclei isolation. Damage principally involved generation of single-stranded regions in otherwise double-stranded DNA fragments; totally single-stranded DNA was not detected by hydroxylapatite chromatography. Caffeine gradient elution suggested formation of single-stranded regions extending for up to several kilobases. In neutral sucrose gradients, differences in sedimentation rates of respective DNA samples consequent upon S1 nuclease digestion could be detected after isolation of nuclei, though not in other circumstances. The observed single-strand-specific nuclease digestion of DNA could apparently be reduced if steps were taken to reduce autodigestion during nuclei isolation by reduction of temperature and covalent cation concentration. The results are discussed in terms of the use of exogenous and endogenous nucleases in chromatin fractionation studies involving isolated nuclei and possible artifactual findings that may be generated by single-strand-specific autodigestion.
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PMID:Single-strand-specific degradation of DNA during isolation of rat liver nuclei. 300 23

Caffeine augmented formation of gastric lesions in rats exposed to restraint plus water-immersion stress for 3 h, together with inhibition of gastric secretion and gastric motility. The etiology of the lesion aggravation by caffeine was studied by measuring several parameters which were relevant to the mucosal defensive factors. Caffeine increased the susceptibility of gastric mucosa to erosive action of acid when simultaneously combined with the stress procedure. Injection of caffeine via an intraperitoneal route, but not via an intraarterial route, caused a decrease in gastric tissue blood flow when no marked fall in body temperature was seen. This indicates that the caffeine-induced decrease in gastric tissue blood flow is not due to its direct action on the gastric mucosal vessels. Hexosamine content of gastric wall tissues, however, was not significantly changed in caffeine-pretreated rats at 3 h after stress. These results suggest that caffeine aggravates stress-induced gastric lesions through some mechanism in reducing mucosal blood flow which is responsible for liability of mucosal autodigestion.
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PMID:The etiology of caffeine-induced aggravation of gastric lesions in rats exposed to restraint plus water-immersion stress. 713 Dec 32