Home About us Contact
|
Home About us Contact | ||
|
|
||
Disrupting Chemicals (disrupting + chemical)
Kinds of Disrupting Chemicals Selected AbstractsEnhanced Treatment of Trace Pollutants by a Novel Electrolytic Cell,ENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 6 2006Y. Sakakibara Abstract Continuous experiments were conducted to evaluate the electrolytic performance of a novel 3-dimensional electrolytic cell consisting of granular Pt/Ti electrodes. The electric current efficiency to decompose indigotrisulfonate was approx. 96,%, while energy consumption was one to two orders of magnitude smaller than that for O3 treatment. Furthermore, the cell was successfully applied to treat trace endocrine disrupting chemicals (EDCs) and chlorinated compounds. Energy consumption was in the range of 2 to 10 Wh/m3. From these results, it was concluded that the present electrolytic cell would be a feasible alternative to conventional oxidation processes in water treatment. [source] Effects of nonylphenol, bisphenol a, and their mixture on the viviparous swordtail fish (Xiphophorus helleri)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2001Hyeong-Il Kwak Abstract A number of fish species have been used for studies on endocrine disrupting chemicals (EDCs). However, despite the widespread use of oviparous fish, relatively little attention has been given to viviparous species. This study investigated the effects of EDCs in a viviparous fish and examined the possible usefulness of the fish as an alternative model for the studies on EDCs. Swordtails (Xiphophorus helleri) were exposed to nonylphenol (NP), bisphenol A (BPA), and their mixture. Both short-term (3-d) and relatively long-term (60-d) exposures were carried out using adult male and 30-d-old juvenile fish, respectively. Following the short-term exposure, both NP and BPA caused vitellogenin mRNA expression. Flow cytometric analysis and terminal deox-ynucleotidyl transferase assay on the testes of treated fish indicated reproductive damage. Histopathological analysis found degenerative and necrotic cells in seminiferous tubules following the exposure to 100 ppb NP. The testes with lesions were also associated with highly suppressed spermatogenesis. Following the long-term exposure, both NP and BPA exposures significantly affected the growth of swordtails. In all cases, the results showed that the mixture was always more potent than a single chemical and that swordtail fish can be a useful model for the study of endocrine disruptors. [source] Effects of possible endocrine disruptors on MyD88-independent TLR4 signalingFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2008Takahiro Ohnishi Abstract Endocrine disrupting chemicals (EDCs) may potentially worsen infectious diseases because EDCs disturb human immune function by interfering with endocrine balance. To evaluate the influence of EDCs on the innate immune function of macrophages, we investigated the effects of 37 possible EDCs on lipopolysaccharide-induced activation of the IFN-, promoter. Alachlor, atrazine, benomyl, bisphenol A, carbaryl, diethyl phthalate, dipropyl phthalate, kelthane, kepone, malathion, methoxychlor, octachlorostyrene, pentachlorophenol, nonyl phenol, p -octylphenol, simazine and ziram all inhibited the activation. Kepone and ziram showed strong inhibitory effects. Aldicarb, amitrole, benzophenone, butyl benzyl phthalate, 2,4-dichlorophenoxy acetic acid, dibutyl phthalate, 2,4-dichlorophenol, dicyclohexyl phthalate, diethylhexyl adipate, diethylhexyl phthalate, dihexyl phthalate, di- n -pentyl phthalate, methomyl, metribuzin, nitrofen, 4-nitrotoluene, permethrin, trifluralin, 2,4,5-trichlorophenoxyacetic acid and vinclozolin had no significant effects at 100 ,M. These results indicate that some agrochemicals and resin-related chemicals may potentially inhibit macrophage function, which suggests that endocrine disruptors may influence the development of infectious diseases. [source] Combined exposure to anti-androgens causes markedly increased frequencies of hypospadias in the ratINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 2 2008S. Christiansen Summary The incidence of hypospadias is increasing in young boys, but it remains unclear whether human exposure to endocrine disrupting chemicals plays a role. Risk assessment is based on estimation of no-observed-adverse-effect levels for single compounds, although humans are exposed to combinations of several anti-androgenic chemicals. In a mixture (MIX) study with three androgen receptor antagonists, vinclozolin, flutamide and procymidone, rats were gavaged during gestation and lactation with several doses of a MIX of the three chemicals or the chemicals alone. External malformations of the male reproductive organs were assessed on PND 47 using a score from 0 to 3 (normal to marked) for hypospadias. Markedly increased frequencies were observed after exposure to a MIX of the three chemicals compared to administration of the three chemicals alone. Anogenital distance at PND 1, nipple retention at PND 13, and dysgenesis score at PND 16 were highly correlated with the occurrence of hypospadias, and MIX effects were seen at doses where each of the individual chemicals caused no observable effects. Therefore, the results indicate that doses of anti-androgens, which appear to induce no hypospadias when judged on their own, may induce a very high frequency of hypospadias when they interact in concert with other anti-androgens. [source] The possible role of endocrine disrupting chemicals in the aetiology of cryptorchidism and hypospadias: a population-based case,control study in rural SicilyINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2007P. Carbone Abstract This was an open case,control study of the possible association between parental occupational and domestic exposures to potential endocrine disrupting chemicals (EDC) assessed by questionnaire and cryptorchidism and hypospadias in their offspring in the agricultural area of Ragusa. Cases of infants born between 1998 and 2002 with either of these two malformations (n = 90), and controls (n = 203), were recruited through the paediatric services (for cases) and a random sample of healthy infants attending the same services born in the same period of time (for controls). Data on occupational and environmental exposures of parents prior to and during the index case (or control), were collected through interviews with both parents. Concerning occupational exposures, we did not find a statistically significant increase in risk among parents directly involved in agricultural work. We did find a non-statistically significant increase in risk for cryptorchidism in mothers employed in agriculture [adjusted odds ratios (OR) 2.97; 95% confidence interval (CI) 0.77,11.47] and with probable exposure to pesticides (adjusted OR 2.74; 95% CI 0.72,10.42). Fathers who had indirect contact with agricultural products (transport and retail) had an increased risk (not statistically significant) for cryptorchidism (adjusted OR 2.45; 95% CI 0.63,9.59) and hypospadias and cryptorchidism combined (adjusted OR 2.24; 95% CI 0.67,7.48). Increases in risk of the two malformations pooled were also observed in relation to the mother's age below 25 (adjusted OR 1.99; 95% CI 0.97,4.09), to the presence of genital disease of the father (adjusted OR 2.41; 95%C I0.94,6.17), and the mother (adjusted OR 3.47;95% CI1.34,8.99), to low birth weight of the infant (adjusted OR 4.49; 95% CI 1.23,16.31). Increased risk was also observed for mothers consuming alcohol during pregnancy (adjusted OR 3.09; 95% CI 0.98,9.66), and for couples who conceived while using condoms (adjusted OR 2.12; 95% CI 1.02,4.41). The study therefore provides only limited support to the hypothesis of a possible association between the risk of cryptorchidism and hypospadias and the occupational exposure to EDC and agricultural work. [source] Secretion of cortisol and aldosterone as a vulnerable target for adrenal endocrine disruption , screening of 30 selected chemicals in the human H295R cell modelJOURNAL OF APPLIED TOXICOLOGY, Issue 8 2008Erik Ullerås Abstract The adrenal gland is a vulnerable target for toxic insult. Disruption of adrenal steroidogenesis and hormone secretion may cause serious effects on human health. A human in vitro model is needed to predict effects, and elucidate mechanisms of endocrine disruption and adrenal toxicity. The human adrenocortical cell line H295R has been used to screen for effects on sex hormones. Here, we have analyzed the effect of 30 potential endocrine disrupting chemicals on the secretion of cortisol and aldosterone from the H295R cells, using specific ELISA assays. The effect of chemicals was analyzed for basal and forskolin- or angiotensin II-stimulated hormone secretion. The chemicals were tested at the highest concentration where they displayed no evident unspecific cytotoxicity. Quantitative and qualitative differences in effects on hormone secretion were demonstrated for the various chemicals. A subset of the chemicals displayed different effects on cortisol and aldosterone secretion, and in some cases the effects were different between basal and stimulated hormone secretion. Aminoglutethimide, prochloraz, ketoconazole, 6-hydroxyflavone, imazalil and etomidate had the most marked inhibitory effects on cortisol (with or without forskolin) and ketoconazole, 6-hydroxyflavone, imazalil and etomidate had the most marked effects on aldosterone (with or without angiotensin II). The results are discussed in terms of known effects, structural similarity and possible mechanisms. We have shown that adrenal steroidogenesis is a vulnerable target for toxic insult and that the H295R assay is a useful in vitro model for screening purposes. Copyright © 2008 John Wiley & Sons, Ltd. [source] Determination of rat hepatocellular glutathione by reversed-phase liquid chromatography with fluorescence detection and cytotoxicity evaluation of environmental pollutants based on the concentration changeBIOMEDICAL CHROMATOGRAPHY, Issue 4 2001Toshimasa Toyo'oka Three methods for the determination of rat hepatocellular thiols by high-performance liquid chromatography (HPLC) with fluorescence (FL) detection have been developed. The thiols in the cells were tagged with three fluorogenic reagents, SBD-F, ABD-F and DBD-F. These reagents could permeate into cells and effectively reacted with thiols to produce highly fluorescent derivatives. These derivatives fluoresced in the long wavelength region at around 530,nm (excitation at around 380 nm). The five biological thiols tagged were perfectly separated by reversed-phase liquid chromatography and were sensitively and selectively detected without any interference from endogenous substanaces. The main thiol in the cells was reduced GSH and the concentration was at the,mM level. The proposed procedures were applied to the determination of hepatocellular GSH after treatment of environmental pollutants such as volatile organic compounds (VOC) and endocrine disrupting chemicals (EDC). From the comparison of intracellular GSH concentration, the test compounds were classified into four groups: compounds of strong depletion (eg triphenyltin chloride, hexachlorocyclohexene, nonylphenol, bromoacetic acid, 4-chlorobenzyl chloride and 1,3-dichloropropene), slight decrease (eg bisphenol A, benzo[a]pylene, carbon tetrachloride and benzene), slight increase (eg bromoform and toluene), and no effect (eg 1,1,1-trichloroethane, 1,1,2-trichloroethane and 1,2-dichloroethane). Although the decrease of GSH concentration does not reflect the cytotoxicity of chemicals, the proposed procedure utilizing isolated rat hepatpcytes seems to be useful for investigating the bioactivation of VOC, and EDC, etc. Copyright © 2001 John Wiley & Sons, Ltd. [source] Molecular epidemiology of hypospadias: Review of genetic and environmental risk factorsBIRTH DEFECTS RESEARCH, Issue 10 2003Jeanne M. Manson Hypospadias is one of the most common congenital anomalies in the United States, occurring in approximately 1 in 125 live male births. It is characterized by altered development of the urethra, foreskin, and ventral surface of the penis. In this review, the embryology, epidemiology, risk factors, genetic predisposition, and likely candidate genes for hypospadias are described. Recent reports have identified increases in the birth prevalence of mild and severe forms of hypospadias in the United States from the 1960s to the present. Studies in consanguineous families and small case series have identified allelic variants in genes controlling androgen action and metabolism that cause hypospadias, but the relevance of these findings to the general population is unknown. Concern has also focused on whether exposure to endocrine disrupting chemicals (EDC) with antiandrogenic activity is the cause of this increase. Hypospadias is believed to have a multifactorial etiology in which allelic variants in genes controlling androgen action and metabolism predispose individuals to develop this condition. When genetic susceptibility is combined with exposure to antiandrogenic agents, a threshold is surpassed, resulting in the manifestation of this birth defect. A clear role for exposure to antiandrogenic environmental chemicals has yet to be established in the etiology of hypospadias, although results from laboratory animal models indicate that a number of environmental chemicals could be implicated. Molecular epidemiology studies that simultaneously examine the roles of allelic variants in genes controlling androgen action and metabolism, and environmental exposures are needed to elucidate the risk factors for these anomalies and the causes of the increased rate of hypospadias. Birth Defects Research (Part A), 2003. © 2003 Wiley-Liss, Inc. [source] Testicular dysgenesis syndrome: foetal origin of adult reproductive problemsCLINICAL ENDOCRINOLOGY, Issue 4 2009Christine Wohlfahrt-Veje Summary The evidence for the existence of testicular dysgenesis syndrome (TDS) is presented in this review. Several epidemiological studies have shown that conditions like cryptorchidism, impaired spermatogenesis, hypospadias and testicular cancer can be associated as risk factors for each other. Thus, the risk of testis cancer is significantly increased in men with cryptorchidism and/or infertility. Several recent studies point towards early dysgenesis of the foetal testis as the biological link between these disorders. Dysgenesis has been demonstrated in biopsies of the contralateral testis of men with testis cancer and in infertile men. The histological evidence includes immature seminiferous tubules with undifferentiated Sertoli cells, microliths and Sertoli-cell only tubules. Dysgenetic testes often have an irregular ultrasound pattern, where microliths may also be visible. Our current hypothesis is that maternal exposure to endocrine disrupting chemicals may contribute to the pathogenesis of TDS. Animal experiments have shown that all TDS symptoms, except testicular cancer, can be induced by foetal exposure to anti-androgenic chemicals. However, the cause of TDS in humans remains to be determined. [source] | ||||||||||||||||