1,721,209 research outputs found
DISPLACEMENT OF |3H|-N6-CYCLOEXYLADENOSINE BINDING TO RAT CORTICAL MEMBRANES BY AN HYDROALCOHOLIC EXTRACT OF VALERIANA OFFICINALIS
No full textA method for disposing of lysates from cells analyzed for DNA damage by filter elution assay.
No full textModulation of muscarinic receptor-stimulated phosphoinositide breakdown by sulfhydryl group modification is a general response in different rat brain regions and depends on the stage of brain development.
No full textSimultaneous determination of DNA double strand breaks and DNA fragment size in cultured mammalian cells exposed to hydrogen peroxide/histidine or etoposide with CHEF electrophoresis.
No full textA CHEF (contour clamped, homogenous electric field) assay allowing the measurement of chemically-generated DNA DSBs (double strand breaks), and the simultaneous estimation of the size of the resulting double stranded DNA fragments, in a single gel run, has been developed. This method combines a very high sensitivity for detecting DNA DSBs with a very good resolution over a broad range of megabase--sized DNA. This information can be obtained in a 68 h gel run, a time which is slightly elevated as compared to the CHEF DSB assay (approximately 20 h), but dramatically reduced as compared to other CHEF protocols utilized for resolving DNA fragments of 0.2-5.7 Mb (5-14 days). Treatment with 5-10 microM etoposide or 50-100 microM hydrogen peroxide/300 microM histidine produced DNA fragments with a mean size of 7.7 x 10(5) bp (from or = 5.7-2.2 Mb), respectively
The induction/loss of the oxidant-resistant phenotype of Chinese hamster ovary (CHO) cell variants does not correlate with sensitivity to DNA single strand breakage by hydrogen peroxide.
No full textHydrogen peroxide resistant variants of Chinese hamster ovary (CHO) cells characterized by different levels of resistance to growth inhibition induced by the oxidant displayed a decreased susceptibility to the induction of DNA single strand breakage by hydrogen peroxide. Resistance to DNA damage, however, was maximal in cells resistant to killing by low concentrations of H2O, and did not increase further in cells characterized by a much higher resistance to the toxic action of the oxidant. Different sensitivities to the induction of DNA single strand breakage observed in wild type and resistant sublines were related to a decreased susceptibility/differential depletion of H2O2, rather than being dependent on different velocities in DNA repair processes. Growth of resistant cells in the absence of H2O2 resulted in a rapid loss of resistance to induction of DNA strand scission by H2O2. Cells retained resistance to the growth-inhibitory effect of the oxidant under conditions where resistance to the production of DNA single strand breaks was lost. Experiments aimed at elucidating the molecular basis for resistance to DNA damage induction by H2O2 have demonstrated that this effect is dependent upon the catalase activity of the specific sublines as well as on their different total protein content
Alternative mechanism for hydroperoxide-induced DNA single strand breakage.
No full textThe results presented in this study point out the existence of similarities as well as differences in the DNA-damaging effects of organic vs. inorganic hydroper- oxides in human myeloid leukemia U937 cells. On the one hand, the formation of DNA single strand breaks (SSBs) induced by either hydrogen peroxide (H2O2) or tert-butylhydroperoxide (tBu-OOH) was prevented by iron chelators, was not affected by antioxidants or glucose omission before and during peroxide exposure and was enhanced by prior catalase depletion. Furthermore, H2O2- and tBu-OOH-induced DNA strand scission were also detected after treatment at 0 degrees C. On the other hand, H2O2, but not tBu-OOH or cumene hydroperoxide (cum-OOH), produced DNA strand scission in isolated nuclei and post-lysed DNA samples. In addition, lowering the basal intracellular calcium concentration with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) markedly reduced the DNA-damaging efficiency of tBu-OOH while promoting only a slight decline in the number of DNA SSBs induced by H2O2 Taken together, these results are consistent with the commonly held theory that DNA damage caused by H2O2 is mediated by the formation of hydroxyl radicals. tBu-OOH-induced DNA single strand breakage appears to involve both the formation of H2O2 and a rise in cytosolic calcium ions
The influence of early postnatal treatment with haloperidol on the effects induced by small and large doses of apomorphine on locomotion of adult rats
No full textChronic administration of haloperidol (0.5 mg/kg, s.c.) during early postnatal life did not modify the effects produced by a small dose of apomorphine (0.02 mg/kg, s.c.) on the locomotor activity of adult rats; conversely, the reduction of locomotion induced by a large dose of apomorphine (1 mg/kg, s.c.) was much more kared in haloperidol-pretreated rat than in saline-pretreated ones. The differential ontogeny of dopamine auto- and postsynaptic receptors could be partly responsible for the different influence of postnatal treatment with haloperidol on the responsiveness of the adult to small and large doses of apomorphin
Interaction of thiocolchicoside with [3H]strychnine binding sites in rat spinal cord and brainstem. Eur. J. Pharmacol. 318, 201-204, 1996.
No full text- …
