start-ver=1.4 cd-journal=joma no-vol=33 cd-vols= no-issue=3 article-no= start-page=89 end-page=95 dt-received= dt-revised= dt-accepted= dt-pub-year=2011 dt-pub=20110812 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Exposure to Cigarette Smoke Increases Urate Level and Decreases Glutathione Level in Larval Drosophila melanogaster en-subtitle= kn-subtitle= en-abstract= kn-abstract=Recently, we reported experimental evidence to support the notion that in Drosophila melanogaster, urate is involved in defense against toxic effects of environmental cigarette smoke (ECS). To obtain further information pertaining to the defense mechanisms involving urate and other antioxidants, the present study measured the levels of urate, its precursors and glutathione, and SOD activity in larval flies of wild-type strains (Oregon-R and Canton-S) and two urate-null mutant strains (ma-l and ry1) following exposure to ECS for various durations. In both wild type strains, unlike the case in either of the mutant strains, the urate level significantly increased above the basal level in a manner dependent on the duration of ECS exposure. Similar increases in the level of urate precursors were found in Canton-S and in both of the urate-null strains. There was a slight increase in glutathione level above the control level following ECS exposure for a short time, followed by an exposure-dependent decrease to less than 60% of the control level within the exposure range used in all of the four strains. On the other hand, no appreciable change was found in the SOD activity prior to or following ECS exposure, irrespective of the strain examined. In terms of the survival of treated larvae to adulthood under the conditions used for the measurements of urate and others, it was found that wild-type strain Canton-S was as sensitive as the urate-null mutant strains and clearly more sensitive than wild-type strains Oregon-R and Hikone-R. This was so despite the fact that, compared with Oregon-R, Canton-S contained urate at relatively higher levels prior to and following ECS exposure, and that the glutathione levels in Canton-S prior to and following treatment were comparable with those in other strains. These results are discussed with respect to the involvement of urate and glutathione in defense against the toxicity of ECS and the possible existence of another defense mechanism which is deficient in the Canton-S strain. en-copyright= kn-copyright= en-aut-name=FujiwaraMasaru en-aut-sei=Fujiwara en-aut-mei=Masaru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HamatakeYuko en-aut-sei=Hamatake en-aut-mei=Yuko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ArimotoSakae en-aut-sei=Arimoto en-aut-mei=Sakae kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=OkamotoKeinosuke en-aut-sei=Okamoto en-aut-mei=Keinosuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SuzukiToshinori en-aut-sei=Suzuki en-aut-mei=Toshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NegishiTomoe en-aut-sei=Negishi en-aut-mei=Tomoe kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=5 en-affil= kn-affil=School of Pharmacy, Shujitsu University affil-num=6 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University en-keyword=environmental cigarette smoke kn-keyword=environmental cigarette smoke en-keyword=uric acid kn-keyword=uric acid en-keyword=glutathione kn-keyword=glutathione en-keyword=oxidative stress kn-keyword=oxidative stress en-keyword=survival kn-keyword=survival en-keyword=Drosophila kn-keyword=Drosophila END start-ver=1.4 cd-journal=joma no-vol=36 cd-vols= no-issue=1 article-no= start-page=1 end-page=9 dt-received= dt-revised= dt-accepted= dt-pub-year=2014 dt-pub=20140228 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Effects of Oral Administration of Non-genotoxic Hepato-hypertrophic Compounds on Metabolic Potency of Rat Liver en-subtitle= kn-subtitle= en-abstract= kn-abstract=It remains uncertain why non-genotoxic compounds that result in liver hypertrophy cause liver tumors. In an effort to resolve this issue, we examined whether liver post-mitochondrial fraction (S9) prepared from rats treated with non-genotoxic compounds affected the genotoxicity of pro-mutagens. Known hepatotoxic compounds, such as piperonyl butoxide (PBO), decabromodiphenyl ether (DBDE), beta-naphthoflavone (BNF), indole-3-carbinol (I3C) and acetaminophen (AA), were orally administered to male and female F344 rats at doses sufficient to cause liver hypertrophy. Rats received diets containing each test compound for 3 days, 4 weeks or 13 weeks, and were then kept for 4 weeks without the test chemical. S9 prepared from the livers of each group was used for the Ames test with 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), benzo[a]pyrene (BaP) and N-nitrosodimethylamine (NDMA). In both sexes, liver hypertrophy was observed following administration of all test compounds, and was then reversed to the control state when administration ceased. The mutagenicity of MeIQx, BaP and NDMA increased with the use of S9 derived from rats treated with non-genotoxic compounds other than AA. DBDE administration had a marked effect on the mutagenicity of BaP (over a 30-fold increase in females) and NDMA (about a 20-fold increase in males). To estimate the involvement of metabolic enzymes in the alteration of mutagenicity, we measured the activity of ethoxyresorufin-O-deethylase (EROD) and methoxyresorufin-O-demethylase (MROD) (phase I enzymes), and UDP-glucuronosyltransferase (UGT) and glutathione S-transferase (GST) (phase II enzymes) in each S9 sample. The activity of phase I enzymes increased, even at the 3rd day following administration, and then decreased gradually, except in the case of AA, while the activity of phase II enzymes increased slightly. These results suggest that non-genotoxic hepato-hypertrophic compounds may be partly involved in carcinogenesis by modulating the metabolism of pre-carcinogens incorporated from the environment, in a manner that is dependent on sex and pre-incorporated chemicals. en-copyright= kn-copyright= en-aut-name=FangXing en-aut-sei=Fang en-aut-mei=Xing kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NunoshibaTatsuo en-aut-sei=Nunoshiba en-aut-mei=Tatsuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YoshidaMidori en-aut-sei=Yoshida en-aut-mei=Midori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=NishikawaAkiyoshi en-aut-sei=Nishikawa en-aut-mei=Akiyoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=NemotoKiyomitsu en-aut-sei=Nemoto en-aut-mei=Kiyomitsu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=DegawaMasakuni en-aut-sei=Degawa en-aut-mei=Masakuni kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ArimotoSakae en-aut-sei=Arimoto en-aut-mei=Sakae kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=OkamotoKeinosuke en-aut-sei=Okamoto en-aut-mei=Keinosuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=TakahashiEizo en-aut-sei=Takahashi en-aut-mei=Eizo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=NegishiTomoe en-aut-sei=Negishi en-aut-mei=Tomoe kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=2 en-affil= kn-affil=International Christian University affil-num=3 en-affil= kn-affil=National Institute of Health Sciences affil-num=4 en-affil= kn-affil=National Institute of Health Sciences affil-num=5 en-affil= kn-affil=School of Pharmaceutical Sciences, University of Shizuoka affil-num=6 en-affil= kn-affil=School of Pharmaceutical Sciences, University of Shizuoka affil-num=7 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=8 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=9 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University affil-num=10 en-affil= kn-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University en-keyword=liver hypertrophic compound kn-keyword=liver hypertrophic compound en-keyword=metabolism kn-keyword=metabolism en-keyword=mutation kn-keyword=mutation en-keyword=Ames test kn-keyword=Ames test END start-ver=1.4 cd-journal=joma no-vol=73 cd-vols= no-issue=1-2 article-no= start-page=59 end-page=66 dt-received= dt-revised= dt-accepted= dt-pub-year=2003 dt-pub=200311 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Alternative methods to evaluate the protective ability of sunscreen against photo-genotoxicity en-subtitle= kn-subtitle= en-abstract= kn-abstract=

Numerous epidemiological investigations show that sunlight is carcinogenic to humans and that the use of sunscreen may be effective in decreasing the risk of skin cancer. The biological activity of a sunscreen is evaluated by its ability to protect human skin from erythema as represented by a Sun Protection Factor (SPF). We propose that the sunscreen's protective effect against sunlight-induced genotoxicity, including mutation, should also be taken into account. In this study we examined the protective ability of sunscreens against natural sunlight and UV-induced genotoxicity in Drosophila somatic cells. We prepared three kinds of sunscreen samples, each with an SPF value of 20, 40 or 60 and compared their protective activities with commercial sunscreens. When a sunscreen of SPF 20, 40 or 60 was pasted on the plastic cover of a petri dish in which Drosophila larvae were exposed to the sun or UV lamps, genotoxicity decreased as the SPF of the sunscreen increased, relative to levels of genotoxicity observed in samples without sunscreen. However, the protective abilities of sunscreens were unexpectedly not so different from each other. To reveal the relationship between the protective activity of sunscreen and the wavelength of light with which larvae were irradiated through the sunscreen, we measured the transmittance of light through the petri dish cover on which the sunscreen was pasted. Effective protection was demonstrated by removing components of light whose wavelengths were below 315 nm. We suggest, that the measurement of anti-genotoxic activity and the determination of the wavelengths of light transmitted through the sunscreen should be an alternative method for evaluating the effectiveness of a sunscreen.

en-copyright= kn-copyright= en-aut-name=ToyoshimaMegumi en-aut-sei=Toyoshima en-aut-mei=Megumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HosodaKanako en-aut-sei=Hosoda en-aut-mei=Kanako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HanamuraMiho en-aut-sei=Hanamura en-aut-mei=Miho kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=OkamotoKeinosuke en-aut-sei=Okamoto en-aut-mei=Keinosuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KobayashiHiroshi en-aut-sei=Kobayashi en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NegishiTomoe en-aut-sei=Negishi en-aut-mei=Tomoe kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University affil-num=4 en-affil= kn-affil=Okayama University affil-num=5 en-affil= kn-affil=Shiseido Research Center affil-num=6 en-affil= kn-affil=Okayama University en-keyword=sunscreen kn-keyword=sunscreen en-keyword=sunlight kn-keyword=sunlight en-keyword=UVB kn-keyword=UVB en-keyword=somatic cell mutation kn-keyword=somatic cell mutation en-keyword=genotoxicity kn-keyword=genotoxicity en-keyword=transmittance kn-keyword=transmittance en-keyword=Drosophila melanogaster kn-keyword=Drosophila melanogaster END