Gokhan Cesur

Mobile phone-induced myocardial oxidative stress: protection by a novel antioxidant agent caffeic acid phenethyl ester.

Electromagnetic radiation (EMR) or radiofrequency fields of cellular mobile phones may affect biological systems by increasing free radicals, which appear mainly to enhance lipid peroxidation, and by changing the antioxidant defense systems of human tissues, thus leading to oxidative stress. Mobile phones are used in close proximity to the heart, therefore 900 MHz EMR emitting mobile phones may be absorbed by the heart. Caffeic acid phenethyl ester (CAPE), one of the major components of honeybee propolis, was recently found to be a potent free radical scavenger and antioxidant, and is used in folk medicine. The aim of this study was to examine 900 MHz mobile phone-induced oxidative stress that promotes production of reactive oxygen species (ROS) and the role of CAPE on myocardial tissue against possible oxidative damage in rats. Thirty rats were used in the study. Animals were randomly grouped as follows: sham-operated control group (N: 10) and experimental groups: (a) group II: 900 MHz EMR exposed group (N: 10); and (b) group III: 900 MHz EMR exposed+CAPE-treated group (N: 10). A 900 MHz EMR radiation was applied to groups II and III 30 min/day, for 10 days using an experimental exposure device. Malondialdehyde (MDA, an index of lipid peroxidation), and nitric oxide (NO, a marker of oxidative stress) were used as markers of oxidative stress-induced heart impairment. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were studied to evaluate the changes of antioxidant status. In the EMR exposed group, while tissue MDA and NO levels increased, SOD, CAT and GSH-Px activities were reduced. CAPE treatment in group III reversed these effects. In this study, the increased levels of MDA and NO and the decreased levels of myocardial SOD, CAT and GSH-Px activities demonstrate the role of oxidative mechanisms in 900 MHz mobile phone-induced heart tissue damage, and CAPE, via its free radical scavenging and antioxidant properties, ameliorates oxidative heart injury. These results show that CAPE exhibits a protective effect on mobile phone-induced and free radical mediated oxidative heart impairment in rats.

Active smoking causes oxidative stress and decreases blood melatonin levels

Oxidative effects via free radical generation in smokers have been widely investigated. They cause lipid peroxidation, oxidation of proteins and damage to mainly lung and other tissues. In humans, antioxidative capacity of serum is related to antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and melatonin. The effect of cigarette smoking on plasma levels of melatonin and antioxidant enzymes has not been established together yet. Also, it may not be clear if melatonin levels are affected by smoking and melatonin has a protective effect on cigarette smoking-induced free radical damage. The aim of this study is to investigate the relationship between smoking and antioxidant capacity including melatonin, a powerful endogenous antioxidant, and antioxidant enzymes in teenage girls who are active smokers. Additionally, malondialdehyde (MDA) levels were determined in those who have smoked at least one packet a day for three or more years. MDA levels have been used as a convenient index of the lipid peroxidation-related oxidative damage of tissues. Twenty-one young female active smokers who study at the School of Nursing and 21 nonsmoking students (as controls) at the same school were included in the study. The activities of two principal antioxidant enzymes SOD, GSH-Px and plasma levels of MDA were significantly increased but melatonin content of the blood was significantly decreased as compared to nonsmokers. In spite of an increase in antioxidant enzyme activities, MDA levels were slightly increased in smokers. This indicates that antioxidant self-defence mechanisms may not sufficiently protect the respiratory system from smoke-mediated oxidative injury. This result may be related to low melatonin levels in teenage female smokers. It seems that melatonin can reduce free radical damage to the respiratory system induced by cigarette smoke. Further experimental investigations with exogenous melatonin treatments will be needed.

Endometrial apoptosis induced by a 900-MHz mobile phone: Preventive effects of vitamins E and C

Numerous reports have described the effects induced by an electromagnetic field (EMF) in various cellular systems. The purposes of this study were to examine oxidative stress that promotes production of reactive oxygen species induced by a 900-megahertz (MHz) mobile phone and the possible ameliorating effects of vitamins E and C on endometrial tissue against EMF-induced endometrial impairment and apoptosis in rats. Animals were randomly grouped as follows: (1) sham-operated control group (n=8), (2) 900 MHz EMF-exposed group (n=8; 30 min/d for 30 d), and (3) 900 MHz EMF-exposed group, treated with vitamins E and C (n=8; 50 mg/kg intramuscularly and 20 mg/kg body weight intraperitoneally before daily EMF exposure). Malondialdehyde (an index of lipid peroxidation) was used as a marker of oxidative stress-induced endometrial impairment; Bcl-2, Bax, caspase-3, and caspase-8 were assessed immunohistochemically. In this study, increased malondialdehyde levels in endometrial tissue and apoptosis illustrated the role of the oxidative mechanism induced by exposure to a 900-MHz mobile phone-like device and vitamins E and C; via free radical scavenging and antioxidant properties, oxidative tissue injury and apoptosis were ameliorated in rat endometrium. In conclusion, exposure to 900-MHz radiation emitted by mobile phones may cause endometrial apoptosis and oxidative stress, but treatment with vitamins E and C can diminish these changes and may have a beneficial effect in preventing endometrial changes in rats.

Prevention of mobile phone induced skin tissue changes by melatonin in rat: an experimental study:

Most of the mobile phones in Turkey emit 900 MHz radiation which is mainly absorbed by the skin and, to a lesser extent, muscle. The aim of this study was to investigate the effects the 900 MHz electromagnetic irradiation emitted by these devices on the induction of histopathologic changes in skin and the effect of melatonin (Mel) on any of these changes. Thirty male Wistar-Albino rats were used in the study. The experimental groups were composed of: a nontreated control group, an irradiated group (IR) without Mel and an irradiated with Mel treatment group (IR + Mel). 900 MHz radiation was applied to IR group for 10 days (30 min/day). The IR + Mel group received 10 mg/kg per day melatonin in tap water for 10 days before irradiation. At the end of the tenth day, the skin graft was excized from the thoraco-abdominal area. Histopathologic changes in skin were analyzed. In the IR group, increased thickness of stratum corneum, atrophy of epidermis, papillamatosis, basal cell proliferation, increased granular cell layer (hypergranulosis) in epidermis and capillary proliferation, impairment in collagen tissue distribution and separation of collagen bundles in dermis were all observed compared to the control group. Most of these changes, except hypergranulosis, were prevented with melatonin treatment. In conclusion, exposure to 900 MHz radiation emitted by mobile phones caused mild skin changes. Furthermore, melatonin treatment can reduce these changes and may have a beneficial effect to prevent 900 MHz mobile phone-induced rat skin changes.

The protective effect of caffeic acid phenethyl ester (CAPE) on oxidative stress in rat liver exposed to the 900 MHz electromagnetic field.

In this study, we aimed to investigate the possible protective effects of caffeic acid phenethyl ester (CAPE) on lipid peroxidation (LPO) and the activities of antioxidant enzymes in the liver of rats exposed to the 900 MHz electromagnetic field (EMF). EMF of cellular phones may affect biological systems by increasing free radical, which appear mainly to enhance LPO, and by changing the antioxidative activities of liver, thus leading to oxidative damage. CAPE, an active component of propolis extract, exhibits antioxidant properties and several studies suggest that supplementation with antioxidant can influence EMF exposure induced hepatotoxicity. Thirty male Sprague-Dawley rats were divided into three groups: control (n = 10), 900 MHz EMF (n = 10) and 900 MHz EMF + CAPE (n = 10). CAPE was injected intraperitoneally for 30 days before exposure to EMF. Liver tissue was removed to study the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), xanthine oxidase (XO) and the levels of LPO. The activities of XO, CAT and level of LPO increased in the 900 MHz electromagnetic field (EMF) group compared with the control group, although XO, CAT activities and LPO levels were decreased by 900 MHz EMF + CAPE administration. The activities of SOD and GSH-Px decreased in the 900 MHz EMF group compared with the control group, although their levels were increased by EMF + CAPE administration. It can be concluded that CAPE may prevent the 900 MHz EMF-induced oxidative changes in liver by strengthening the antioxidant defense system by reducing reactive oxygen species and increasing antioxidant enzyme activities.

Ghrelin and adiponectin levels in colostrum, cord blood and maternal serum

Background:  Ghrelin and adiponectin, which are considered to take part in the regulation of energy metabolism, have been found in breast milk and cord blood. The aims of this study were to determine ghrelin and adiponectin levels in colostrum, cord blood and maternal serum and to investigate the correlations between colostrum and cord blood levels of these peptides and the anthropometry of newborn infants and their mothers.

No effects of 900 MHz and 1800 MHz electromagnetic field emitted from cellular phone on nocturnal serum melatonin levels in rats

In this study, the effects of exposure to a 900 MHz and 1800 MHz electromagnetic field (EMF) on serum nocturnal melatonin levels of adult male Sprague-Dawley rats were studied. Thirty rats were used in three independent groups, 10 of which were exposed to 900 MHz, 10 of which were exposed to 1800 MHz and 10 of which were sham-exposed (control). The exposures were performed 30 min/day, for five days/week for four weeks to 900 MHz or 1800 MHz EMF. Control animals were kept under the same environmental conditions as the study groups except with no EMF exposure. The concentration of nocturnal melatonin in the rat serum was measured by using a radioimmunoassay method. There were no statistically significant differences in serum melatonin concentrations between the 900 MHz EMF group and the sham-exposed group (P-0.05). The values at 12:00 pm were 39.119 / 6.5 pg/mL in the sham-exposed group and 34.979 / 5.1 pg/mL in the 900 MHz EMF-exposed group. Also, there were no statistically significant differences in serum melatonin concentrations between the sham-exposed group and the 1800 MHz EMF-exposed group (P-0.05). The values at 12:00 pm were 39.119 / 6.5 pg/mL in the sham-exposed group and 37.969 / 7.4 pg/mL in the exposed group. These results indicate that mobile phones, emitting 900 and 1800 MHz EMF, have no effect on nocturnal serum melatonin levels in rats.

Caffeic Acid Phenethyl Ester Modulates 1800 MHz Microwave-Induced Oxidative Stress in Rat Liver

Microwaves (MW) from cellular phones may affect biological systems by increasing free radicals, which may enhance lipid peroxidation (LP), and by changing the antioxidative activities of the liver, thus leading to oxidative damage. Caffeic acid phenethyl ester (CAPE), an active component of propolis extract, exhibits antioxidant properties and several studies suggest that supplementation with antioxidant can influence MW induced hepatotoxicity. The present study was designed to determine the effects of MW on the liver oxidant/antioxidant system, and the possible protective effects of CAPE on liver toxicity induced by MW. Twenty nine male Spraque- Dawley rats were divided into three groups: control (n = 9), 1800 MHz MW (n = 10) and 1800 MHz MW + CAPE (n = 10). CAPE was injected intraperitoneally for 30 days before exposure to MW. Liver tissue was removed to study the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), xanthine oxidase (XO) and the levels of LP. The activities of XO, CAT and level of LP increased in MW group compared with the control group although XO and LP levels were decreased by MW + CAPE administration. The activities of SOD and GSH-Px decreased in MW group compared with the control group. Their levels were increased by MW + CAPE administration. We conclude that CAPE may prevent MW-induced oxidative changes in liver by strengthening the antioxidant defense system, by reducing reactive oxygen species, and by increasing antioxidant enzyme activities.

CHLORPYRIFOS INCREASES THE LEVELS OF HIPPOCAMPAL NMDA RECEPTOR SUBUNITS NR2A AND NR2B IN JUVENILE AND ADULT RATS

The present study investigated the effect of chlorpyrifos on NMDA receptor subunits NR2A and NR2B in juvenile and adult rats. Chlorpyrifos was administered with the dose of 40 and 70 mg/kg to juvenile and adult rats, respectively. Chlorpyrifos significantly inhibited the AChE activity in juvenile and adult rats (p < .05). NR2A and NR2B levels significantly increased in juvenile and adult rats by chlorpyrifos application (p < .05). Increased NR2A and NR2B levels may reflect increased glutaminergic activity, consequently neuronal damage. In the case of neuronal damage, learning and memory could be affected negatively even though NR2A and NR2B increased.

The effect of the prenatal and post-natal long-term exposure to 50 Hz electric field on growth, pubertal development and IGF-1 levels in female Wistar rats

To investigate prenatal and post-natal effects of extremely low frequency (ELF) electric field (EF) on growth and pubertal development, pregnant Wistar rats were randomly distributed among three groups. The pregnant rats of the prenatal group were exposed to 24-hour EF at 50 Hz EF 10 kV/min during pregnancy and their subsequent randomly selected female pups continued to be exposed until puberty. The post-natal group was unexposed to EF during pregnancy, but randomly selected female pups from this group were exposed to EF between delivery and puberty at the same doses and duration as the prenatal group. The third group was a sham-exposed group. The mean birth weight and weight gain of the pups during study period were found significantly reduced in prenatal group than post-natal and sham-exposed groups (p < 0.001). No difference could be found among the three groups for body weight at puberty (p > 0.05). The mean age at vaginal opening and estrous were significantly higher at prenatal group than post-natal and sham-exposed groups (p < 0.001). Serum insulin-like growth hormone-1 (IGF-1) levels were found significantly reduced in prenatal exposure group compared with the other two groups (p < 0.001). There was no difference for birth weight, weight gain, the mean age at vaginal opening and estrous and IGF-1 levels between post-natal and sham-exposed groups (p > 0.05). There was also no difference for FSH, LH and E2 levels at puberty among the three groups (p > 0.05). Histological examination revealed that both the prenatal and post-natal groups had the evidence of tissue damage on hypothalamus, pituitary gland and ovaries. In conclusion, early beginning of prenatal exposure of rats to 24 hours 50 Hz EF at 10 kV/m until puberty without magnetic field (MF) resulted in growth restriction, delayed puberty and reduced IGF-1 levels in female Wistar rats. These effects probably associated with direct toxic effects of EF on target organs. Post-natal exposure to EF at similar doses and duration seems to be less harmful on target organs. Post-natal exposure to EF at similar doses and duration seems to be less harmful.