Reha Demirel

The effects of diazinon on lipid peroxidation and antioxidant enzymes in erythrocytes in vitro.

Diazinon is one of the most widely used organophosphate insecticides (OPI) in agriculture and public health programs. The aim of this study was to investigate how an OPI, diazinon, affects lipid peroxidation (LPO) and the antioxidant defense system in vitro. For this purpose, two experiments were carried out. In experiment 1, the effects of various concentrations of diazinon on LPO and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) in erythrocytes were studied. Each diazinon concentration was incubated with a previously prepared erythrocyte samples at +4°C for 0, 60 and 180 min. After incubation, the malondialdehyde (MDA) levels and the activities of SOD, GSH-Px and CAT were determined. In experiment 2, in order to determine the direct effect of diazinon on the activities of SOD, GSH-Px and CAT, the erythrocytes were haemolysed and incubated with the various concentrations of diazinon at +4°C for 0, 60 and 180 min. In experiment 1, MDA levels and the activities of SOD and GSH-Px increased with increasing diazinon concentration and incubation period, but CAT activity remained unchanged. In experiment 2, SOD activity was significantly decreased, and GSH-Px activity was significantly increased. From these results, it can be concluded that in vitro administration of diazinon results in the induction of erythrocyte LPO and changes the activities of antioxidant enzymes, suggesting that reactive oxygen species may be involved in the toxic effects of diazinon.

Comparative analysis of the protective effects of melatonin and caffeic acid phenethyl ester (CAPE) on mobile phone-induced renal impairment in rat.

Melatonin and caffeic acid phenethyl ester (CAPE), a component of honeybee propolis, were recently found to be potent free radical scavengers and antioxidants. There are a number of reports on the effects induced by electromagnetic radiation (EMR) in various cellular systems. Mechanisms of adverse effects of EMR indicate that reactive oxygen species may play a role in the biological effects of this radiation. The present study was carried out to compare the protective effects of melatonin and CAPE against 900 MHz EMR emitted mobile phone-induced renal tubular injury. Melatonin was administered whereas CAPE was given for 10 days before the exposure. Urinary N-acetyl-β-D-glucosaminidase (NAG, a marker of renal tubular injury) and malondialdehyde (MDA, an index of lipid peroxidation), were used as markers of oxidative stress-induced renal impairment in rats exposed to EMR. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were studied to evaluate the changes of antioxidant status in renal tissue. Urinary NAG and renal MDA were increased in EMR exposed rats while both melatonin and CAPE caused a significant reduction in the levels of these parameters. Likewise, renal SOD and GSH-Px activities were decreased in EMR exposed animals while melatonin caused a significant increase in the activities of these antioxidant enzymes but CAPE did not. Melatonin caused a significant decrease in urinary NAG activity and MDA levels which were increased because of EMR exposure. CAPE also reduced elevated MDA levels in EMR exposed renal tissue, but the effect of melatonin was more potent than that of CAPE. Furthermore, treatment of EMR exposed rats with melatonin increased activities of SOD and GSH-Px to higher levels than those of control rats. In conclusion, melatonin and CAPE prevent renal tubular injury by reducing oxidative stress and protect the kidney from oxidative damage induced by 900 MHz mobile phone. Nevertheless, melatonin seems to be a more potent antioxidant compared with CAPE in kidney. (Mol Cell Biochem 276: 31–37, 2005)

Assessing the Indoor Environment of Primary Schools in the Southwest of Turkey

In developing countries, the effects of natural disasters and accidents are often more serious in those buildings with a high number of occupants as a consequence of deficiencies in the built design and insufficiency of inspections. We have surveyed a number of state primary schools to examine their interior physical environment with respect to school safety and security. We studied all the 37 state primary schools located in the Isparta region of Turkey during the period between March and May of 2002. The results showed that all the schools of the region had a number of inadequacies because they had not been adequately adapted to comply with existing standards. Most of the schools had over-large class sizes, had one or more classrooms in an underground floor (proscribed in areas where there is a high risk of earthquakes), inadequate security and safety precautions to ensure pupil safety and had no proper air ventilation within the classrooms. The survey showed that local and central official bodies must reinforce the need for standards and ensure the implementation of high standards in the schools to ensure the pupil health, safety and security, and that they should work together with parents and other local associations.