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    COMPARISON OF N-ACETYL-L-CYSTEINE AND L-CYSTEINE IN RESPECT TO THEIR TRANSMEMBRANE FLUXES
    (Mezhdunarodnaya Kniga, 2009) Yildiz, D.; Arik, M.; Cakir, Y.; Civi, Z.
    The objective of the present study was to compare cysteine and N-acetyl-L-cysteine in respect to their transmembrane fluxes and find out which one is a better available precursor for the cells and thus better supports the intracellular glutathione synthesis. Cysteine can directly participate in glutathione synthesis, whereas N-acetyl-L-cysteine must be first deacetylated before its incorporation to glutathione. In the present study we investigated and compared the efficiencies of cysteine and N-acetyl-L-cysteine influx and efflux through the erythrocyte membrane. Erythrocytes transported both cysteine and N-acetyl-L-cysteine in a concentration-dependent manner. However, our results demonstrated that cysteine crosses the erythrocyte membranes more efficiently than N-acetyl-L-cysteine does. Treatment of erythrocytes with 5 mM of cysteine or N-acetyl-L-cysteine for 1 hr raised the intracellular free sulfhydryl group (free-SH) levels to 3.37 +/- 0.006 or 2.23 +/- 0.08 mu mol/ml erythrocyte, respectively. Cysteine more effectively than N-acetyl-L-cysteine restored the intracellular free-SH level lowered beforehand. In erythrocytes previously depleted of free-SH, 5 mM cysteine raised the free-SH level to 1.45 +/- 0.075 mu mole/ml within I hr, whereas N-acetyl-L-cysteine at the same concentration raised this level to 0.377 +/- 0.034 mu mole/ml only. The results of our study also revealed that both cysteine and N-acetyl-L-cysteine influx and efflux processes are temperature dependent, indicating that their transport requires biological activity. Our results demonstrate that cysteine is a better thiol precursor for the erythrocytes. Availability of cysteine for the cells is higher than that of N-acetyl-L-cysteine.
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    Comparison of N-Acetyl-L-Cysteine and L-Cysteine in Respect to Their Transmembrane Fluxes
    (Springer Heidelberg, 2009) Yildiz, D.; Arik, M.; Cakir, Y.; Civi, Z.
    The objective of the present study was to compare cysteine and N-acetyl-L-cysteine in respect to their transmembrane fluxes and find out which one is a better available precursor for the cells and thus better supports the intracellular glutathione synthesis. Cysteine can directly participate in glutathione synthesis, whereas N-acetyl-L-cysteine must be first deacetylated before its incorporation to glutathione. In the present study we investigated and compared the efficiencies of cysteine and N-acetyl-L-cysteine influx and efflux through the erythrocyte membrane. Erythrocytes transported both cysteine and N-acetyl-L-cysteine in a concentration-dependent manner. However, our results demonstrated that cysteine crosses the erythrocyte membranes more efficiently as compared to N-acetyl-L-cysteine. Treatment of erythrocytes with 5 mM of cysteine or N-acetyl-L-cysteine for 1 hr raised the intracellular free sulfhydryl group (free-SH) levels to 3.37 +/- 0.006 or 2.23 +/- 0.08 mu mol/ml erythrocyte, respectively. Cysteine more effectively than N-acetyl-L-cysteine restored the intracellular free-SH level depleted beforehand. In erythrocytes previously depleted of free-SH, 5 mM cysteine raised the free-SH level to 1.45 +/- 0.075 mu mol/ml within 1 hr, whereas N-acetyl-L-cysteine at the same concentration raised this level to 0.377 +/- 0.034 mu mol/ml only. The results of our study also revealed that both cysteine and N-acetyl-L-cysteine influx and efflux processes are temperature dependent indicating that their transport requires biological activity. Our results demonstrate that cysteine is a better thiol precursor for the erythrocytes. Availability of cysteine for the cells is higher than that of N-acetyl-L-cysteine.
  • Küçük Resim
    Öğe
    Inhibitory effects of acetylsalicylic acid on exocrine pancreatic carcinogenesis
    (Taylor & Francis Ltd, 2013) Yildiz, H.; Oztas, H.; Yildiz, D.; Koc, A.; Kalipci, E.
    We investigated short (6 months) and long (12 months) term inhibitory effects of low (200 ppm) and high (400 ppm) dosages of acetylsalicylic acid (aspirin) on exocrine pancreatic carcinogenesis. It is known that exocrine pancreatic carcinogenesis can be detected by the presence of atypical acinar cell foci (AACF) in pancreas. We investigated possible inhibitory effects of acetylsalicylic acid in an azaserine-treated rat model. AACF were produced in rats by injection with azaserine according to previous studies. Our findings showed that the number, volume and diameter of pancreatic AACF were reduced after acetylsalicylic acid application. These observations suggest that acetylsalicylic acid may exert a protective effect against neoplastic development of pancreatic acinar cells in azaserine injected rats. Our findings corroborate reports in the literature concerning the effects of aspirin in reducing neoplastic development.