Change of estrogenic activity and release of chloride ion in chlorinated bisphenol a after exposure to ultraviolet B.
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Bisphenol A (BPA) and chlorinated bisphenol A (ClBPAs) were detected in wastewater from waste paper recycling plants. In previous study, we showed the acute cytotoxicity of oxidized products of BPA and ClBPAs generated by ultraviolet (UV) irradiation. However, estrogenic activities of these photoproducts have not been studied. Therefore, we investigated change of estrogenic activities of BPA and ClBPAs [3-chlorobisphenol A (3-ClBPA), 3,3'-dichlorobisphenol A (3,3'-diClBPA) and 3,3',5-trichlorobisphenol A (3,3',5-triClBPA)] after UVB irradiation using yeast two-hybrid assay. The agonist activities of ClBPAs were higher than that of BPA in the absence of S9. ClBPAs irradiated with UVB lost agonist activities. The addition of S9 also completely erased the activity. The antagonist activities of BPA and ClBPAs with or without UVB irradiation were not detected both in the absence or presence of S9. UVB irradiation (0-100 J/cm2) decreased the agonist activity of 3,3'-diClBPA in proportion to increase of released chloride ion. The agonist activity was completely lost at 50 J/cm2 of UVB, of which dose could dissociated almost all chlorine. These findings suggested that UVB irradiation could decrease the estrogenic activity of chlorinated compounds, which was due to the selective release of chloride ion. (+info)
Bringing safe water to remote populations: an evaluation of a portable point-of-use intervention in rural Madagascar.
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Rural populations disproportionately lack access to improved water supplies. We evaluated a novel scheme that employed community-based sales agents to disseminate the Safe Water System (SWS)--a household-level water chlorination and safe storage intervention--in rural Madagascar. Respondents from 242 households in 4 villages were interviewed; all used surface water for drinking water. Respondents from 239 households (99%) had heard of Sur'Eau, the SWS disinfectant; 226 (95%) reported having ever used Sur'Eau, and 166 (73%) reported current use. Current Sur'Eau use was confirmed in 54% of households. Community sales agents effectively motivated their neighbors to adopt a new health behavior that prevents diarrhea. Future work should focus on strategies for sustaining SWS use, factors that motivate community-based sales agents to promote SWS, and the feasibility of scaling up this approach. (+info)
Treating water with chlorine at point-of-use to improve water quality and reduce child diarrhea in developing countries: a systematic review and meta-analysis.
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We conducted a systematic review of all studies that measured diarrheal health impacts in children and the impact on water quality of point-of-use chlorine drinking water treatment. Twenty-one relevant studies were identified from > 856 screened abstracts. Data were extracted and combined using meta-analysis to provide summary estimates of the intervention effect. The intervention reduced the risk of child diarrhea (pooled relative risk: 0.71, 0.58-0.87) and it reduced the risk of stored water contamination with Escherichia coli (pooled relative risk: 0.20, 0.13-0.30). A major finding from this review is that nearly all trials on this topic have been short (median length was 30 weeks). Although not statistically significant, we observed an attenuation of the intervention's reduction of child diarrhea in longer trials. Future studies with multi-year follow-up are required to assess the long-term acceptability and sustainability of health impacts shown by the shorter trials identified in this review. (+info)
Use of 0.1% chlorine dioxide to inhibit the formation of morning volatile sulphur compounds (VSC).
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The aim of this study was to evaluate the VSC-inhibiting effect of a commercially available mouthrinse (0.1% chlorine dioxide) when compared to its placebo. A 2-step double blind, crossover, randomised study was conducted with 14 dental students with healthy periodontium, who refrained from any mechanical plaque and tongue coating control during two 4-day experimental periods. The subjects were instructed to rinse 3 times daily with the assigned product during each period. A 7-day washout interval was established. VSCs levels were measured by a sulphide monitor at the beginning (baseline) and at the end of each experimental period. Statistical analyses were performed using Wilcoxon's and Mann-Whitney's non-parametric tests. At baseline, intragroup analysis revealed that VSCs levels did not differ between groups (p > 0.05); at day 5, the use of the chlorine dioxide mouthrinse did not change the baseline VSCs scores in the control group (p > 0.05), while a 2-fold increase was observed with the use of the placebo mouthrinse (p < 0.05). Intergroup analysis showed a significant difference between the VSCs levels of the test and control groups (40.2 +/- 30.72 and 82.3 +/- 75.63 ppb, p < 0.001) at day 5. Within the limits of this study, the findings suggest that a mouthrinse containing chlorine dioxide can maintain VSCs at lower levels in the morning breath. (+info)
Microwave-assisted amination of a chloropurine derivative in the synthesis of acyclic nucleoside analogues.
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An efficient protocol for the amination of 6-chloropurine derivatives through nucleophilic aromatic substitution under microwave irradiation was developed and applied to the synthesis in two steps of a series of new acyclic nucleosides (acyclovir analogues) starting from commercially available compounds. (+info)
Synthesis and some reactions of 3-chloro-2-(cyanomethylene)-1,2-dihydroquinoxalines.
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2,3-Dichloroquinoxaline and some of its derivatives have been reacted with malononitrile and ethyl cyanoacetate to yield a variety of 3-chloro-2-(cyanomethylene)- 1,2-dihydroquinoxaline derivatives. The reaction of 3-chloro-2-(dicyanomethylene)-1,2- dihydroquinoxaline (2e) with pyridine and its methyl derivatives led to the zwitterionic structures 6a-6c. The structures of the newly synthesized compounds were assigned by spectroscopic data and elemental analyses. (+info)
Effects of inhibitors on anaerobic microbial consortium with enhanced dechlorination activity in polychlorinated biphenyl mixture.
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Characterization was carried out on the anaerobic microbial consortium with enhanced degradation activity toward polychlorinated biphenyls in Kanechlor-300 and Kanechlor-400 mixtures in a burnt soil (BS) culture. The addition of molybdate to the BS culture resulted in the accumulation of less-chlorinated biphenyls such as 4,4'-dichlorinated biphenyl and 2,3',4-trichlorinated biphenyl; however, no such accumulation occurred without molybdate supplementation. No significant effect was observed in individual congeners in the BS culture supplemented with 2-bromoethane sulfonic acid. Analyses involving both the polymerase chain reaction-denaturing gradient gel electrophoresis of partial 16S rRNA genes and respiratory quinones showed that the predominant microorganisms in the BS culture were anaerobic Firmicutes, while sulfate reducers of the phyla Deltaproteobacteria, Firmicutes and Chloroflexi were absent in the culture amended with the inhibitors. No positive correlation was observed between the dechlorination activity and a PCR-based detection of gene fragments of known dechlorinating bacteria. These results suggest that sulfate reducers played an important role in the enhanced anaerobic dechlorination of PCBs in the BS culture. (+info)
Identification by quantitative carrier test of surrogate spore-forming bacteria to assess sporicidal chemicals for use against Bacillus anthracis.
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The spores of six strains of Bacillus anthracis (four virulent and two avirulent) were compared with those of four other types of spore-forming bacteria for their resistance to four liquid chemical sporicides (sodium hypochlorite at 5,000 ppm available chlorine, 70,000 ppm accelerated H2O2, 1,000 ppm chlorine dioxide, and 3,000 ppm peracetic acid). All test bacteria were grown in a 1:10 dilution of Columbia broth (with manganese) incubated at 37 degrees C for 72 h. The spore suspensions, heat treated at 80 degrees C for 10 min to rid them of any viable vegetative cells, contained 1 x 10(8) to 3 x 10(8) CFU/ml. The second tier of the quantitative carrier test (QCT-2), a standard of ASTM International, was used to assess for sporicidal activity, with disks (1 cm in diameter) of brushed and magnetized stainless steel as spore carriers. Each carrier, with 10 microl (> or = 10(6) CFU) of the test spore suspension in a soil load, was dried and then overlaid with 50 microl of the sporicide being evaluated. The contact time at room temperature ranged from 5 to 20 min, and the arbitrarily set criterion for acceptable sporicidal activity was a reduction of > or = 10(6) in viable spore count. Each test was repeated at least three times. In the final analysis, the spores of Bacillus licheniformis (ATCC 14580(T)) and Bacillus subtilis (ATCC 6051(T)) proved to be generally more resistant than the spores of the strains of B. anthracis tested. The use of one or both of the safe and easy-to-handle surrogates identified here should help in developing safer and more-effective sporicides and also in evaluating the field effectiveness of existing and newer formulations in the decontamination of objects and surfaces suspected of B. anthracis contamination. (+info)