Investigation of the oxidative stress condition for occupational exposure to methyl methacrylate.

The purpose of this study is the evaluation of possible toxicological effects on dental personnel, who are exposed to the production materials of prostheses during their entire working life. In this study, the level of methyl methacrylate (MMA) in ambient air was measured as an indicator of external exposure on the personnel. In order to evaluate the possible toxic effects of oxidative stress, which is thought to play an important role in the formation process of many diseases such as cancer, blood samples of volunteers were examined via the ultraviolet-spectroscopic determination of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase antioxidant enzyme activities, comparing occupationally MMA-exposed ( n = 69) and control ( n = 67) groups. In these groups, malondialdehyde (MDA) and glutathione levels were also determined by the same method. The results showed that SOD activity and MDA and glutathione levels were significantly higher in the exposed group when compared with the control group ( p < 0.001). A significant decrease was determined in the glutathione peroxidase activities of the exposed group ( p < 0.05). No significant difference in CAT activities between the groups has been found. When the results obtained in the study are considered, it is suggested that an adaptive response might be developed by dental technicians against low-level MMA exposure.

Risk assessment of allergen metals in cosmetic products.

Cosmetics are one of the most common reasons for hospital referrals with allergic contact dermatitis. Because of the increased use of cosmetics within the population and an increase in allergy cases, monitoring of heavy metals, especially allergen metals, is crucial. The aim of this study was to investigate the concentration of allergen metals, nickel (Ni), cobalt (Co), and chromium (Cr), in the most commonly used cosmetic products including mascara, eyeliner, eye shadow, lipstick, and nail polish. In addition, for safety assessment of cosmetic products, margin of safety of the metals was evaluated. Forty-eight makeup products were purchased randomly from local markets and large cosmetic stores in Istanbul, Turkey, and an atomic absorption spectrometer was used for metal content determination. Risk assessment of the investigated cosmetic products was performed by calculating the systemic exposure dosage (SED) using Scientific Committee on Consumer Safety guideline. According to the results of this investigation in all the samples tested, at least two of the allergen metals, Ni and/or Co and/or Cr were detected. Moreover, 97% of the Ni-detected products, 96% of Cr- and 54% of Co-detected products, contained over 1 µg/g of this metals, which is the suggested ultimate target value for sensitive population and thereby can be considered as the possible allergen. On the basis of the results of this study, SED of the metals was negligible; however, contact dermatitis caused by cosmetics is most probably due to the allergen metal content of the products. In conclusion, to assess the safety of the finished products, postmarketing vigilance and routine monitoring of allergen metals are very important to protect public health.

Assessment of cadmium, lead, and nickel levels in hair care products marketed in Turkey.

This study evaluated the content of cadmium (Cd), lead (Pb), and nickel (Ni) in 105 hair care products commercially available in Turkey. Cd, Pb, and Ni were detected in 40%, 21.91%, and 94.29% of the samples, respectively. Maximum Cd concentrations were detected in two shampoo samples, and the highest Pb level was found in a hair conditioner, all of them were herbal-based formulations. The highest mean levels of Ni were detected in hairstyling agents. The overall results were lower than the Canadian and German regulatory limits; however, according to the European Council Directive and Turkish Cosmetic Legislation, Cd, Pb, and Ni are listed as the substances that are prohibited in any amounts in cosmetics. Moreover, Ni content of 17.14% of the samples was above the limit of allergic contact dermatitis. It is known that these toxic metals tend to accumulate in body and prolonged use of them may potentially pose threat to human health. Thus, regular market monitoring and safer limits should be seriously considered especially for susceptible groups of the population like the pediatric group.

Oxidative stress enzyme status and frequency of micronuclei in heroin addicts in Turkey.

Heroin is among the most widely used and dangerous addictive opiate. The World Health Organization (WHO) estimated that more than 15 million people are under the influence of opiate addiction. The aim of this study was to investigate copper zinc-superoxide dismutase (Cu,Zn-SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GPx) antioxidant enzyme activities, malondialdehyde (MDA) levels and the frequency of micronuclei (MN) in addicts using heroin, the most commonly abused opiate in Turkey. Addicts were defined as individuals diagnosed according to "Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV)" criteria by the "Alcohol and Substance Abuse Treatment and Education Centre-Ankara (AMATEM)". The control group had no addiction. In comparisons between the groups, a significant decrease in Cu,Zn-SOD activity and increases in MDA levels and MN frequency were observed in addicts. It can be concluded that opiates may cause oxidative stress and that antioxidant supplementation, in addition to pharmacological and psychiatric approaches, can reduce the toxicological effects of these opiates.

The effect of levothyroxine replacement therapy on lipid profile and oxidative stress parameters in patients with subclinical hypothyroid.

The purpose of this present study is to investigate the levels of oxidative stress parameters in patients with subclinical hypothyroidism (SH) and the effects of levothyroxine (LT4) replacement therapy on these parameters and lipid profile. At the beginning of the study blood samples were collected from the patients in order to analyse oxidative stress parameters, lipid profile and biochemical markers. After replacement therapy with LT4, in the third month, same tests were performed again. At the baseline superoxide dismutase (SOD) levels were found to be higher in SH patients, compared to the euthyroid group. After LT4 therapy, statistically significant decreases in SOD and catalase levels and increase in HDL-C levels were noticed. LT4 treatment was found to have positive effects on oxidative stress indicators and HDL-C levels.

Cytogenetic analysis of peripheral blood lymphocytes of hospital staff occupationally exposed to low doses of ionizing radiation.

Ionizing radiation is known to induce mutations and cell transformations, predominantly by causing single-strand and double-strand DNA breakage, thereby leading to chromosome instability and carcinogenesis. The aim of this study was to evaluate genotoxic effects in hospital staff exposed to low-dose ionizing radiation in comparison with a selected control group, by using the cytokinesis-blocked micronucleus (CBMN) and sister chromatid exchange (SCE) tests in peripheral blood lymphocytes. The study included 40 exposed radiology staff and 30 control subjects. The frequency of micronuclei (MN) was significantly increased in radiation-exposed groups compared with control persons (p < 0.05). The frequency of SCE did not show any significant difference in the exposed individuals in comparison to the controls. Our results showed that low-level chronic occupational exposure to ionizing radiation causes an increase of MN frequency in chromosomes, even though the absorbed doses were below the permissible limits. Our studies indicate that the CBMN assay is considered to be sensitive test in contrast to SCE analysis to evaluate chromosomal damage induced by ionizing radiation.

Occupational exposure of dental technicians to methyl methacrylate: Genotoxicity assessment.

Dental technicians may be chronically exposed to methyl methacrylate (MMA), used in the production of dental prostheses. We have studied whether occupational exposure to MMA affects genotoxicity biomarkers such as 8-OHdG formation, comet assay, and buccal micronucleus frequency. MMA exposure was assessed via ambient air analysis. Although no significant differences between exposed and non-exposed individuals were seen with respect to blood genotoxicity measurements, we found a higher level of buccal-cell anomalies in the exposed group.

An animal model (guinea pig) of ocular siderosis: histopathology, pharmacology, and electrophysiology.

PURPOSE: Ocular siderosis is a rare sight-threatening complication that occurs after a penetrating ocular injury by an iron-containing foreign body. The purposes of this study were to (i) investigate the histopathology, electrophysiology and iron levels/accumulation in ocular siderosis using an animal (Guinea pig) model and (ii) determine the appropriate timing for follow-up foreign body-removal surgery. MATERIALS AND METHODS: Thirty guinea pigs were divided into five groups (n = 6 animals/group). On day-1, an iron body was inserted into the vitreous of the right eye of all animals; the left eyes were left undisturbed and were used as controls. At the end of each week during the 5-week study period, electroretinography (ERG) was performed on all animals in one of the five groups. Each animal in that group was sacrificed, after which both eyes were enucleated for histopathological and pharmacological evaluation of intraocular iron. RESULTS: Accumulated iron levels of study eyes were significantly higher than those of control eyes (135.13 and 13.55 µg/g, respectively, p < 0.01). In addition, there was a significant decrease in electrophysiological responses of study eyes. During the first week, iron levels were higher in study eyes than control eyes, but neither histological iron accumulation nor decreased electrophysiological responses could be detected. By the end of the second week, increased iron accumulation was observed histologically in intraocular tissues, along with signs of retinal toxicity, as verified by decreased electrophysiological responses. CONCLUSIONS: The present study indicates that the 14th day after a penetrating eye injury by an iron-containing intraocular foreign body represents a clinically critical threshold, after which structural damage to and functional alterations in ocular tissues occur.