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Assessment of micronuclei induction in peripheral erythrocytes of fish exposed to xenobiotics under controlled conditions.The aim of the present study was to standardize and to assess the predictive value of the cytogenetic analysis by MN test in fish erythrocytes as a biomarker for marine environmental contamination. MN frequency baseline in erythrocytes was evaluated in a number of fish species from a reference area (S. Teresa, La Spezia Gulf) and genotoxic potential of a number of common chemical contaminants and mixtures was determined in fish experimentally exposed in aquarium under controlled conditions. Fish (Scophthalmus maximus) were exposed for 3 weeks to 50 ppb of single chemicals (dialkyl phthalate, bisphenol A, tetrabromodiphenyl ether), 30 ppb nonylphenol and mixtures (North Sea oil and North Sea oil with alkylated phenols). Chromosomal damage was determined as micronuclei (MN) frequency in fish erythrocytes. Nuclear anomalies such as blebbed, notched and lobed nuclei were also recorded. Significant increase in MN frequency was observed in erythrocytes of fish exposed to bisphenol A and tetrabromodiphenylether. Chemical mixture North Sea oil+alkylated phenols induced the highest MN frequency (2.95 micronucleated cells/1000 cells compared to 1 MNcell/1000 cells in control animals). The study results revealed that micronucleus test, as an index of cumulative exposure, appears to be a sensitive model to evaluate genotoxic compounds in fish under controlled conditions.
CYP2C19 polymorphisms in patients with gastric and colorectal carcinoma.BACKGROUND: It has been reported that up to 80% of human cancers arise as a consequence of environmental exposure and host susceptibility factors. Environmental carcinogens are predominantly metabolized by the cytochrome P450 (CYP) superfamily of drug- or xenobiotic-metabolizing enzymes. Genetic variations in these enzymes affect individuals' susceptibility to carcinogens. AIM OF THE STUDY: The aim of this study was to evaluate the relationship between CYP2C19 polymorphism and susceptibility to these cancers by means of CYP2C19 genotyping among Turkish subjects. METHODS: DNAof subjects were isolated from leukocytes by high pure template preparation kit (Roche Diagnostics, GmbH, Mannheim, Germany) and genotypes were detected by LightCycler CYP2C19 Mutation Detection Kit by real-time PCR with LightCycler instrument (Roche Diagnostics, cat. no. 3113914). RESULTS: Being male was associated with a 3.5-fold (OR: 4.27, CI: 2.27-8.05) and 4.27-fold (OR: 3.50, CI: 1.948-6.301) risk for colorectal and gastric carcinoma, respectively. The CYP2C19*3 heterozygote genotype was not found in either gastric or colorectal carcinoma patients. Although the frequency of CYP2C19*2 heterozygote genotype is high in patients with gastric and colorectal carcinoma, it is not significantly associated with cancer (OR: 1.79, CI: 0.829-3.865 and OR: 1.998, CI: 0.961-4.154, respectively). CONCLUSION: Although the frequency of CYP2C19*2 heterozygote genotype is high in our patients with gastric and colorectal carcinoma, there is no the relationship between CYP2C19 polymorphism and susceptibility to these cancer.
Glucoraphanin, the bioprecursor of the widely extolled chemopreventive agent sulforaphane found in broccoli, induces phase-I xenobiotic metabolizing enzymes and increases free radical generation in rat liver.Epidemiological and animal studies linking high fruit and vegetable consumption to lower cancer risk have strengthened the belief that long-term administration of isolated naturally occurring dietary constituents could reduce the risk of cancer. In recent years, metabolites derived from phytoalexins, such as glucoraphanin found in broccoli and other cruciferous vegetables (Brassicaceae), have gained much attention as potential cancer chemopreventive agents. The protective effect of these micronutrients is assumed to be due to the inhibition of Phase-I carcinogen-bioactivating enzymes and/or induction of Phase-II detoxifying enzymes, an assumption that still remains uncertain. The protective effect of glucoraphanin is thought to be due to sulforaphane, an isothiocyanate metabolite produced from glucoraphanin by myrosinase. Here we show, in rat liver, that while glucoraphanin slightly induces Phase-II enzymes, it powerfully boosts Phase-I enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), nitrosamines and olefins. Induction of the cytochrome P450 (CYP) isoforms CYP1A1/2, CYP3A1/2 and CYP2E1 was confirmed by Western immunoblotting. CYP induction was paralleled by an increase in the corresponding mRNA levels. Concomitant with this Phase-I induction, we also found that glucoraphanin generated large amount of various reactive radical species, as determined by electron paramagnetic resonance (EPR) spectrometry coupled to a radical-probe technique. This suggests that long-term uncontrolled administration of glucoraphanin could actually pose a potential health hazard.