Induction of ROS, p53, p21 in DEHP- and MEHP-exposed LNCaP cells-protection by selenium compounds.

This study was designed to investigate the hypothesis that the toxic effects of di(2-ethylhexyl)phthalate (DEHP), the most abundantly used plasticizer and ubiquitous environmental contaminant that cause alterations in endocrine and spermatogenic functions in animals is mediated through the induction of reactive oxygen species (ROS) and activation of nuclear p53 and p21 proteins in LNCaP human prostate adenocarcinoma cell line. Protective effects of two selenocompounds, sodium selenite (SS) and selenomethionine (SM) were also examined. It was demonstrated that 24 h exposure of the cells to 3 mM DEHP or its main metabolite, mono(2-ethylhexyl)phthalate (MEHP, 3 µM) caused strongly amplified production of ROS. Both SS (30 nM) and SM (10 µM) supplementations reduced ROS production, and p53 and p21 activation that induced significantly only by MEHP-exposure. The overall results of this study indicated that the induction of oxidative stress is one of the important mechanisms underlying the toxicity of DEHP and this is mainly through the effects of the metabolite, MEHP. Generated data also emphasized the critical role of Se in modulation of intracellular redox status, implicating the importance of the appropriate Se status in cellular response against testicular toxicity of phthalates.

Cytotoxicity in ciprofloxacin-treated human fibroblast cells and protection by vitamin E.

Quinolones (Qs) were shown to have cytotoxic effects in various cell lines including human carcinoma cells; however, mechanism of these effects was not fully understood. To investigate the possibility of the involvement of an oxidative stress induction in this mechanism of action, we examined viability of human fibroblast cells exposed to a Q antibiotic, ciprofloxacin (CPFX), and measured lipid peroxidation and total glutathione (GSH) levels, and activities of catalase (Cat), superoxide dismutases (SODs), glutathione peroxidase (GPx). The effects of vitamin E pretreatment on those parameters were also examined. Our results showed that the effect of CPFX on the viability of the cells, as determined by neutral red uptake assay, was time dependent. Cytotoxicity was not observed in the concentration range of 0.0129-0.387 mM CPFX when the cells were incubated for 24 hours. However, significant level of cytotoxicity was observed at concentrations 0.129 and 0.194 mM, and >0.129 mM, following 48 and 72 hours of exposure, respectively. When the cells were exposed to 0.194 mM CPFX for 48 hours, the level of lipid peroxidation increased and the content of total GSH decreased significantly; activities of total SOD, Mn SOD and CuZn SOD did not change; the decrease observed in the activity of Cat was not significant; and the activity of GPx was highly variable. Vitamin E pretreatment of the cells provided significant protection against CPFX-induced cytotoxicity; lowered the level of lipid peroxidation significantly, but increased the total GSH content only moderately; no change was observed in the activities of Cat and total SOD, but a significant increase in Mn SOD and a significant decrease in CuZn SOD were noticed. These results suggested that CPFX-induced cytotoxicity on human fibroblast cell cultures is related to oxidative stress, and vitamin E pretreatment can afford a protection.

Status of selenium and antioxidant enzymes of goitrous children is lower than healthy controls and nongoitrous children with high iodine deficiency.

In order to investigate the relations of iodine deficiency and/or goiter with selenium (Se) and antioxidant enzyme (AOE) status, we determined the relevant parameters of goitrous high school children living in an endemic goiter area of Turkey. Subjects were selected by a simple random sampling technique after screening the whole population of the high schools of two towns by neck palpation. The results of the goitrous group (n = 48, aged 15-18 yr) were compared with those of nongoitrous control children (n = 49) from the same populations, and with an outside control group (n = 24) from a lower-goiter-prevalence area. The overall prevalence of goiter was 39.6% in the high school population of the area. Activities of erythrocyte AOE (glutathion peroxidase, catalase, and superoxide dismutase) and concentrations of plasma and erythrocyte Se and urinary iodine were found to be significantly lower in goitrous children than both in-region and out-region of the control groups. When the whole study group was reclassified according to the severity of iodine deficiency, it was found that the AOE and Se status of those control children without goiter but with high iodine deficiency was significantly higher than goitrous children, although they did not differ from nondeficient control group. This might be the result of the possibility that goitrous children are exposed of oxidative stress, which may introduce alterations to the antioxidant defense system and/or the antioxidant status is relatively lower in goitrous children than those children who are highly iodine-deficient but did not develop goiter. The results of this study seem to support the view that the risk of goiter development may be higher in highly iodine-deficient children with lower enzymatic antioxidant and Se status.

Microsomal metabolism of ciprofloxacin generates free radicals.

Ciprofloxacin (CPFX) is a widely used fluoroquinolone antibiotic with a broad spectrum of activity. However, clinical experience has shown a possible incidence of undesirable adverse effects including gastrointestinal, skin, hepatic, and central nervous system (CNS) functions, and phototoxicity. Several examples in the literature data indicate that free radical formation might play a role in the mechanism of some of these adverse effects, including phototoxicity and cartilage defects. The purpose of this study is to investigate free radical formation during the metabolism of CPFX in hepatic microsomes using electron spin resonance (ESR) spectroscopy and spin trapping technique. We then investigate the effects of a cytochrome P450 inhibitor, SKF 525A, Trolox, and ZnCl2 on CPFX-induced free radical production. Our results show that CPFX induces free radical production in a dose- and time-dependent manner. The generation of 4-POBN/radical adduct is dependent on the presence of NADPH, CPFX, and active microsomes. Furthermore, free radical production is completely inhibited by SKF 525A, Trolox, or ZnCl2.

Cypermethrin-induced oxidative stress in rat brain and liver is prevented by vitamin E or allopurinol.

Considering that the involvement of reactive oxygen species (ROS) has been implicated in the toxicity of various pesticides, this study was designed to investigate the possibility of oxidative stress induction by cypermethrin, a Type II pyrethroid. Either single (170 mg/kg) or repeated (75 mg/kg per day for 5 days) oral administration of cypermethrin was found to produce significant oxidative stress in cerebral and hepatic tissues of rats, as was evident by the elevation of the level of thiobarbituric acid reactive substances (TBARS) in both tissues, either 4 or 24 h after treatment. Much higher changes were observed in liver, increasing from a level of 60% at 4 h up to nearly 4 times the control at 24 h for single dose. Reduced levels (up to 20%) of total glutathione (total GSH), and elevation of conjugated dienes ( approximately 60% in liver by single dose at 4 h) also indicated the presence of an oxidative insult. Glutathione-S-transferase (GST) activity, however, did not differ from control values for any dose or at any time point in cerebral and hepatic tissues. Pretreatment of rats with allopurinol (100 mg/kg, ip) or Vitamin E (100 mg/kg per day, ig, for 3 days and a dose of 40 mg/kg on the 4th day) provided significant protection against the elevation of TBARS levels in cerebral and hepatic tissues, induced by single high dose of oral cypermethrin administration within 4 h. Thus, the results suggest that cypermethrin exposure of rats results in free radical-mediated tissue damage, as indicated by elevated cerebral and hepatic lipid peroxidation, which was prevented by allopurinol and Vitamin E.

Effect of some phthalate esters in human cells in the comet assay.

Phthalate esters are among the most extensively used industrial chemicals and are widely distributed in the environment. Di-(2-ethylhexyl)phthalate (DEHP) and its hydrolysis product mono-(2-ethylhexyl)phthalate (MEHP) have been examined for genotoxic activity on previous occasions. Only MEHP was found to cause chromosome damage in CHO cells but was without effect in the sister chromatid exchange and hypoxanthine guanine phosphoribosyl assay. DEHP was found to be a weak direct acting mutagen in Salmonella typhimurium strain TA100, the mutagenic activity of which could be abolished by rat liver microsomes (S9 mix). The clastogenicity and weak mutagenicity suggest a possible contributory role for these compounds in the observed carcinogenicity of the phthalates, which have been thought predominantly to be linked to cancer pathology through proliferation of hepatic peroxisomes. The present study showed that these compounds could produce DNA damage in human blood cells in the Comet assay and also, that rat liver microsomes could abolish the effect of DEHP. Thus in the intact animal, no response may be observed.

Induction of lipid peroxidation and alteration of glutathione redox status by endosulfan.

The oxidant stress-inducing effects of endosulfan, a chlorinated hydrocarbon insecticide of the cyclodiene group, have been examined following ig administration of single and repeated doses. A single dose of 30 mg/kg (approximately 30% LD50) endosulfan significantly (p < 0.001) increased the TBARS and, hence, the lipid peroxidation in cerebral and hepatic tissues of rats. Administration of endosulfan with doses of 10 or 15 mg/kg/d for 5 d has also induced lipid peroxidation significantly (p < 0.05). The same doses caused a significant alteration in glutathione redox status of cerebral and hepatic tissues, where total glutathione and oxidized glutathione were measured by an enzymatic cycling procedure. Selenium levels were also determined and compared with controls. With repeated doses, oxidant stress was more pronounced in cerebral tissue, where endosulfan shows a GABA-antagonistic activity. The possible relationship between the neurotoxicity of endosulfan and its oxidant stress-inducing effect was discussed.

Humoral and cellular immune parameters in untreated and phenytoin-or carbamazepine-treated epileptic patients.

The peripheral blood lymphocyte subsets, serum immunoglobulins (Ig A, G, M), and C3 and C4 complement protein concentrations were determined in 40 healthy subjects, 30 phenytoin-treated, 22 carbamazepine-treated and 38 untreated epileptic patients. The levels of beta-lymphocytes, IgM and C3 complement proteins were found to be significantly higher in untreated epileptics than in healthy controls (P < 0.01, P < 0.02 and P < 0.05, respectively). The absolute number of beta-lymphocytes appeared to be unaffected by phenytoin or carbamazepine treatment; however, IgM levels were significantly lower in carbamazepine-treated patients than both epileptic (P < 0.01) and healthy (P < 0.05) controls. Phenytoin-treated patients had a significant reduction in the mean IgA and IgG levels compared to healthy and epileptic controls (P < 0.05). With both drug treatments, significantly lower T-suppressor lymphocyte counts and thus higher T-helper to T-suppressor lymphocyte ratios were observed with respect to healthy and epileptic controls. Our results demonstrate that while phenytoin decreases serum IgA and IgG levels, carbamazepine reduces IgM levels significantly, and untreated epileptics show immune profiles significantly different to those of healthy subjects, suggesting that epilepsy per se may be associated with certain immune aberrations induced by antiepileptic drugs.

Selenium status in Turkey. II. Serum selenium concentration in healthy residents of different ages in Ankara.

In this study we determined the serum selenium concentraction of 218 healthy individuals at different ages, in Ankara, using a spectrofluorimetric method. The mean selenium levels were found to be 45 +/- 10 micrograms/L in cord blood at birth; 69 +/- 13 micrograms/L in 2 month-12 month-old infants; 77 +/- 12 micrograms/L in children aged > 12 months-16 years; and 74 +/- 16 micrograms/L in adults aged 18-48 years. Selenium concentrations showed age dependency, increasing significantly in childhood but decreasing after 40 years of age. No relation to the sex, dietary habits, socioeconomical status or hematological parameters such as hemoglobin concentration and white blood cell count, was observed. The results obtained thus suggest that the status of selenium in Ankara residents is in a range that could be considered as safe and adequate.

Serum selenium status in children with iron deficiency anemia.

Serum selenium concentration was investigated in 40 children with iron deficiency anemia and in 40 control subjects matched for age, sex and geographical origin. A spectrofluorometric method was used for determination of the selenium level. It was found to be significantly lower (p < 0.001) in the patient group, which consisted of both normally developed and malnourished children. Patients also having pica had higher levels of selenium compared to patients without pica. There was no relation between the serum selenium concentration and hematological parameters such as hemoglobin, serum iron, serum iron binding capacity and unsaturated iron binding capacity. However the results of 15 patients followed during iron therapy indicated that the duration of the anemic period may affect the selenium concentration. This study also suggests the effectiveness of iron and selenium administration.

Selenium status in Turkey. I. Serum selenium levels in infants and children in Ankara.

This study was initiated to evaluate the status of selenium in Turkish residents. Serum selenium level of 76 healthy children, living in Ankara, aged 2 mo-13 y was determined by a spectrofluorometric method. Average selenium level was found to be 88.1 +/- 12.4 micrograms/L (mean +/- SD). Selenium levels showed a tendency to increase with age and mean selenium level in early infancy was lower than that of school children; no relation to the sex and hematological parameters such as hemoglobin concentration and white blood cell counts were observed.

Serum immunoglobulins, complement levels and lymphocyte subpopulations in phenytoin-treated epileptic patients.

The peripheral blood lymphocytes, serum immunoglobulins, C3 and C4 complement protein concentrations of 20 patients with idiopathic epilepsy who were receiving phenytoin were examined and compared with 30 healthy controls in order to obtain a detailed profile of the effects of the drug on the humoral and cellular immune systems. The T-lymphocyte subsets were identified using monoclonal antibodies. A significant decrease in suppressor T-cells (p less than 0.05) and an increase in the ratio of T-helper to T-suppressor lymphocytes (p less than 0.01) have been found. Furthermore, an increase in B-lymphocytes (p less than 0.01) and a significant rise in serum Ig M concentrations (p less than 0.05) have been observed. No significant changes in serum concentrations of Ig G, Ig A and complement proteins were detected.

Epidemiological aspects of childhood poisonings in Ankara: a 10-year survey.

In the 10-year period 1975-1984, 1188 children were admitted to the Children's Hospital of Hacettepe University in Ankara with a diagnosis of poisoning. Retrospective analysis of their medical records showed that the incidence of poisoning with medicinal drugs was 64.0%, while pesticides accounted for 17.8% and plants for 6.7% of total cases. The majority (69.9%) of cases were due to accidental poisoning, 70.6% of which occurred in children under 5 years of age; 15.1% of the poisonings were diagnosed as therapeutic mishaps of which 68.3% involved children under 5 years of age. Analgesics (186 cases), barbiturates (176 cases) and tranquilizers (37 cases) were the most common drugs encountered, however, the two drugs most frequently overused were aspirin (146 cases) and Optalidon (175 cases). Overall mortality was 4.9% (58 cases). Fifty per cent of fatalities were due to accidental poisoning while 41.4% (24 cases) were due to therapeutic mishaps. This study is presented as a background to the need for the development of a Poison Information Service for Ankara.

Self poisoning in children: a ten year survey.

All children, 17 years of age or less, admitted to the Children's Hospital of Hacettepe University Medical Center in Ankara during the period of 1975 to 1984 with a diagnosis of poisoning were studied. Of the 1188 cases reviewed, mode of poisoning was deliberate self-poisoning in a total of 152 cases (12.8%). Drugs accounted for 95.4%, insecticides for 3.9% and carbon monoxide for only 0.7% of the overall suicide attempts or gestures. Analgesics and tranquilizers were the most common agents encountered, however the major drug used for self-poisoning was a barbiturate containing analgesic, Optalidon. The incidence of self-poisoning was 79.0% in the age group 13-17 of the overall poison admissions and in all of the age groups self-poisoning showed a significant (p less than 0.001) sex difference with definite prevalence of girls.

Effects of exposure to air pollution and smoking on the placental aryl hydrocarbon hydroxylase (AHH) activity.

Aryl hydrocarbon hydroxylase (AHH) activities were determined in placental tissues of 152 nonsmoker or exsmoker women who live in Ankara and 125 nonsmoker women who live in areas surrounding Ankara. Levels of AHH were also determined in the placentas of 52 cigarette smokers. The mean AHH activity in the Ankara group was 11.17 +/- 5.41; in the control group, 6.44 +/- 5.48; and for smokers, 45.68 +/- 53.36, which indicates significant differences (p less than .001). There was a strong correlation (r = 0.89) between the AHH activities of individuals who live in Ankara and smoke content of the air. Placental AHH activity did not show any relation to the age, nutritional and dietary habits, factors of indoor pollution, duration of pregnancy, nor did the weight, length and Apgar score of the babies.

Gas chromatographic analysis of acetophenone oxime and its metabolites.

A gas-liquid chromatographic (GLC) method has been developed for monitoring the metabolic reduction of acetophenone oxime or oxidative metabolism of the corresponding amine, alpha-methylbenzylamine in liver homogenates. The oxime, amine, n-hydroxy-alpha-methylbenzylamine and acetophenone are quantitatively determined after GLC separation of components with temperature programming on an SP-2401-DB-coated column. The first three compounds were silylated with N,O-bis(trimethylsilyl)-acetamide prior to chromatographic analysis to enhance the stability and improve the chromatographic properties of these components. The effluent gas was monitored with flame ionization detection, and permitted quantitation of components at sub-microgram/ml levels with reproducibility between injections of +/-2%. The optimal composition of enantiomeric mixtures of (R,S)-alpha-methylbenzylamines formed during metabolic reduction of acetophenone oximes were determined by conversion to diastereomeric amides and subsequent GLC analysis.

Metabolic rearrangement of fluorenone oxime to phenanthridinone.

Fluorenone oxime is metabolized in vivo in the rat to phenanthrifinone which is excreted in the urine. The structure of the metabolite has been determined by comparison of chromatographic and spectral properties of the metabolites with authentic phenanthridinone.