AbstractThe in vivo genotoxic potential of bisphenol A using the comet assay in mice and in human sperm cells in vitro without metabolizing enzymes was studied. Male mice were exposed by oral gavage to the following doses of bisphenol A (0 125, 250 and 500?mg/kg body weight). DNA damage was investigated in liver, kidney, testes, urinary bladder, colon and lungs cells. In testicular cells, a significant increase in DNA strand breaks was observed in the lowest, but not in the medium or highest dose groups. Histopathological investigation of the testicular samples did not show any treatment dose-related effects. No DNA strand breaks were observed in any of the other investigated tissues. In human sperm cells in vitro, bisphenol A did not induce DNA strand breaks. 相似文献
The biochemical basis for resistance to metal ion toxicity is emerging though it is complicated by the different resistance mechanisms. Several strategies for resistance to toxic metal ions have been identified:
The development of energy driven efflux pumps which keep toxic element levels low in the interior of the cell. Such mechanisms have been described for Cd(II) and As(V).
Oxidation (e.g. AsO2‐ to AsO43‐) or reduction (e.g. Hg2+ to Hg0) can enzymatically and intracellularly convert a more toxic form of an element to a less toxic form.
The biosynthesis of intracellular polymers which serve as traps for the removal of metal ions from solution such as traps have been described for cadmium, calcium, nickel and copper.
The binding of metal ions to cell surfaces.
The precipitation of insoluble metal complexes (e.g. metal sulfides and metal oxides) at cell surfaces.
Biomethylation and transport through cell‐membranes by diffusion controlled processes.
In this short review I shall discuss the implications of biomethylation as a detoxification mechanism for microorganisms as well as for certain higher organisms. 相似文献
In order to assist an integrated development of ionic liquids (ILs), a study on the sorption, distribution, and cytotoxicity of a series of 1-alkyl-3-methyl imidazolium tetrafluoroborates with C6 rat glioma cells has been performed. Cellular sorption and distribution among three cellular fractions (cytosol, nuclei, and membranes) were analysed by reversed-phase HPLC (RP-HPLC). Compounds with longer 1-alkyl substituents were sorbed with higher enrichment factors and sorption coefficients per protein than those with shorter 1-alkyl chains. The 1-octyl-3-methyl imidazolium cation (C8MIM) was enriched 17-folds whereas C6MIM and C4MIM were enriched by factors of 3.5 and 2.3, respectively. After fractionation of cells by centrifugation, about 8% of C8MIM was found in the nuclear fractions. The cytotoxicity as estimated by the tetrazolium reductase assay was increasing with the lengths of the 1-alkyl chains from C4MIM to C10MIM. Consistently, cell proliferation rates were decreasing with increasing lengths of the 1-alkyl chains. The results reveal the correlations between lipophilicity, cellular sorption, and cytotoxicity. 相似文献
Small farmers generally spray pesticides manually and often do not use complete protective equipment. The standard test to detect pesticide exposure, which may be associated with toxicity, is the determination of serum cholinesterase, but in chronic exposure to low doses, this test is less sensitive. In this study, in a group sampled among pesticide sprayers without signs of intoxication, cholinesterase, thiobarbituric acid reactive substances (TBARS), catalase (Cat), and superoxide dismutase (Sod) activities were analyzed. Cholinesterase activity was only slightly lower in the farmer group in relation to the control group. However, TBARS and Cat activities were 3-fold increased in the farmers in comparison to the controls. Sod activity was similar in both groups. The group of pesticide sprayers that did not use the complete protective equipment presented a significantly higher level of TBARS than the group that used the complete protective equipment. Therefore, the determination of TBARS and catalase can be useful to identify individuals that are chronically exposed to low doses of pesticides. 相似文献
The cytotoxicity of 13 and 22 nm aluminum oxide (Al2O3) nanoparticles was investigated in cultured human bronchoalveolar carcinoma-derived cells (A549) and compared with 20 nm CeO2 and 40 nm TiO2 nanoparticles as positive and negative control, respectively. Exposure to both Al2O3 nanoparticles for 24 h at 10 and 25 µg mL?1 doses significantly decreased cell viability compared with control. However, the cytotoxicity of 13 and 22 nm Al2O3 nanoparticles had no difference at 5–25 µg mL?1 dose range. The cytotoxicity of both Al2O3 nanoparticles were higher than negative control TiO2 nanoparticles but lower than positive control CeO2 nanoparticles (TiO2 < Al2O3 < CeO2). A real-time single cell imaging system was employed to study the cell membrane potential change caused by Al2O3 and CeO2 nanoparticles using a membrane potential sensitive fluorescent probe DiBAC4(3). Exposure to the 13 nm Al2O3 nanoparticles resulted in more significant depolarization than the 30 nm Al2O3 particles. On the other hand, the 20 nm CeO2 particles, the most toxic, caused less significant depolarization than both the 13 and 22 nm Al2O3. Factors such as exposure duration, surface chemistry, and other mechanisms may contribute differently between cytotoxicity and membrane depolarization. 相似文献
The potential risks from oral intake of soil antimony (Sb) depends mainly on the amount of metal ingested and its bioavailability. Relative bioavailability may be determined by comparing Sb present in soil to a reference compound, taking into account accumulation in different target tissues or excretion. However, due to the lack of scientific knowledge concerning the fate of Sb in the organism, there is a need to study the absorption and distribution of Sb in order to select target tissues for assessment of bioavailability of Sb in soils. Thus, 45 piglets were exposed to a soluble pentavalent antimony salt (KSb(OH)6), for 15 days at concentrations ranging from 0–1600 µg Sb/kg body weight (BW) per day. Following the exposure period, blood, plasma, liver, spleen, kidneys, hair, bone, bile and urine were obtained to measure Sb concentrations by ICP-MS. Results showed that tissue Sb levels were dose-related. Higher Sb concentrations were found in urine, kidneys, hair, bone and liver. Sb(V) was not detectable in blood and plasma. In the case of highly contaminated soil with soluble forms of Sb in concentrations ranging from 200–1600 µg Sb/kg BW, kidneys, liver and spleen are the most reliable compartments to determine Sb bioavailability from soil. However, for the soils with lower levels of contamination and a low Sb bioaccessibility, urine may serve as a relevant compartment. 相似文献