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Öğe Inhibitory effects of Aspirin on Azaserine initiated pancreatic carcinogenesis in rat(2008) Yildiz H.; Koc A.; Oztas H.; Yildiz D.The experiment was designed to investigate the effects of aspirin on the exocrine pancreas in azaserine-rat model. In azaserine treated rats and azaserine and aspirin treated rats were observed to include acidophillic atypical acinar cell foci (AACF). The observed reduction in stereological parameters in asazerine initiated aspirin treated group (AzAsp) in comparison with azaserine treated group (AzCt) suggest that azaserine induced pancreatic carcinogenesis may be inhibited by aspirin treatment in exocrine pancreas.Öğe L-cysteine influx and efflux in human erythrocytes: The role of red blood cells in redox and metabolite homeostasis in the plasma(2006) Yildiz D.; Ates B.H.; Uslu C.; Oztas H.The objective of this study was to investigate L-cysteine influx and efflux in human erythrocytes. L-cysteine is an amino acid required for glutathione synthesis in erythrocytes. In addition to being incorporated into glutathione, the soluble antioxidant L-cysteine plays a role in the maintenance of a proper intracellular or extracellular redox status. Recent investigations have pointed out that L-cysteine may contribute to redox homeostasis in the plasma and in the periplasm of some bacteria. Thus L-cysteine availability in the plasma may influence the oxidized/reduced state of several other metabolites normally found in the plasma. Our L-cysteine uptake studies demonstrated that erythrocytes can respond to an increase in the L-cysteine concentration in the extracellular media and influx L-cysteine in a concentration dependent-manner. The L-cysteine efflux is also time and concentration dependent. Erythrocytes pretreated with higher concentration of L-cysteine displayed higher efflux rates. Erythrocytes pretreated with L-cysteine 1 mM displayed efflux and increased the free-SH concentrations up to 0.184 ± 0.010 mM in the incubation media in 1 hr. While this concentration reached 0.843 ± 0.012 mM in 10 mM-L-cysteine pretreated erythrocytes. Our results also showed that the L-cysteine efflux is partly mediated by the Alanine-Serine-Cysteine (ASC) system. The presence of alanine or serine in the incubation media decreased the rate of efflux by about 16%. Our results also showed that the L-cysteine efflux process is not a simple diffusion but a carrier-mediated process. When compared with N-acetyl-L-cysteine (NAC), which is known to diffuse through the membranes, L-cysteine displayed a higher efflux rate under the same conditions. Pretreatment of erythrocytes with L-cysteine 4 mM increased the free-SH concentration to 0.48 ± 0.005 mM whereas the same concentration of NAC brought the free-SH concentration to 0.36 ± 0.01 mM in the incubation media. Our results suggest that erythrocytes may contribute to redox and metabolite homeostasis of the plasma.Öğe Research on misconceptions of 11spi_supthspii_sup class students about the subjects of adhesion, cohesion and water intake in plants(2013) Oztas F.; Akay M.; Kalipci E.; Gokler I.; Oztas H.It is well known that pupils usually have some sort of misconception (alternative view) about plants' sucking of water and water solute substances from soil. How pupils are pretend pupils the physical, chemical and biological events during sucking process water and water solute substances via roots is a debatable subject of biology education. For this, the aim of this research has been designated as to work out how 11 th grade secondary school pupils comment have been occurring physical, chemical and biological events during sucking process water and water solute substances in plants. As the space of present research were Tavsancali{dotless} Secondary School 11th grade pupils (Kulu-Konya-Turkey). A questionnaire prepared in the light of present literature knowledge cover totally 10 open, 4 closed ended questions has been applied to pupils. The findings of this study have been shown that pupils were having some sort of misconceptions about plants' sucking water and water solute substances by plants. In the light of guidance of these findings it is possible to advice that on the base of constructive teaching techniques the concept of plants' sucking water and water solute substances should be evaluated and should made more meaningful for pupils. © Sila Science.Öğe Ultrastructural changes in pancreatic acinar cells of fatty acids fed rat(2008) Oztas H.; Koc A.; Yildiz D.The objective of the present study was to investigate the ultra structural changes in pancreatic acinar cells in azaserine initiated and fatty acid fed rats. Azaserine initiated male Leeds strain rats were fed a diet containing 20% of oleic acid or equivalent amount of stearic acid for upto 18 months and then the pancreatic tissues were studied by electron microscopy. The results have shown that cytoplasmic lipid droplets were profoundly increased in acinar cells of azaserine initiated oleic acid fed rats. Conversely, the acinar cells of azaserine initiated and stearic acid fed rats possessed unusally pale cytoplasmic fat droplets. These results suggest that the dietary administration of fatty acids result in changes in the composition of intracellular fat droplets in azaserine initiated acinar cells. The present results appear to support the view that dietary administration of fatty acids may changes ultra structural pattern of acinar cells.
