The pulse polarographic behavior of N-nitrosopyrrolidine and two of its derivatives, N-nitrosoproline and N-nitroso-4-hydroxyproline, has been investigated in buffered solutions over a range of pH. The effects of temp...
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Previously, we reported that X-irradiation enhanced the signal decay of a spin probe injected into whole mice measured by in vivo ESR, and that the observed enhancement was suppressed by the preadministration of cyste...
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Previously, we reported that X-irradiation enhanced the signal decay of a spin probe injected into whole mice measured by in vivo ESR, and that the observed enhancement was suppressed by the preadministration of cysteamine, a radioprotector [Miura, Y., Anzai, K., Urano, S. and Ozawa, T. (1997) Free Rad. Biol. Med. 23: 533-540]. In the present study, the suppression activity of the X-ray-induced increase in the ESR signal decay rate (termed suppression index, SI) was measured for several radioprotectors: 5-hydroxytryptamine (5-HT), S-2-(3-aminopropylamino)-ethylphosphorothioic acid (WR-2721), 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl (TEMPOL), cimetidine, interleukin-1 beta (IL-1 beta) and stem cell factor (SCF). The enhancement of the ESR signal decay of carbamoyl-PROXYL due to X-irradiation was suppressed by a treatment with all of the radioprotectors examined, showing positive SI values. However, a dose-dependency of 5-HT or WR-2721 was not observed, suggesting that several mechanisms exist for radioprotection and a modification of the signal decay rate. Although the in vivo ESR system cannot be used in place of the 30-day survival method for the assessment of radioprotectors, this system might be applicable to in vivo, non-invasive screening prior to using the 30-day survival method.
Experiments involving 14C-labeled amines showed that proline is more likely to be the precursor of nitrosopyrrolidine formation than spermidine or putrescine in fried bacon. The data are consistent with a mechanism in...
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Experiments involving 14C-labeled amines showed that proline is more likely to be the precursor of nitrosopyrrolidine formation than spermidine or putrescine in fried bacon. The data are consistent with a mechanism involving formation of nitrosoproline from sodiun nitrite and free proline during processing with subsequent decarboxylation of nitrosoproline during frying.
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