Masarykova univerzita přírodovědecká fakulta

5.Závěr

Cílem diplomové práce bylo hodnocení genotoxického potenciálu látky EHMC. K tomuto hodnocení byly použity dva modely genotoxických testů SOS Chromotest a UmuC test, který byl znovu zaveden do laboratoře RECETOX v inovované podobě za použití vhodnějšího chromogenního substrátu CPRG.

Důležitým výstupem bylo zejména srovnání odpovědi v těchto testech jednotlivých isomerů cis a trans, jelikož cisEHMC nebylo doposud na genotoxicitu testováno. Veškeré informace v literatuře se týkají pouze stabilnějšího isomeru trans. Látka EHMC byla vybrána jako nejvhodnější UV filtr pro tuto studii, neboť je jedním z nejpoužívanějších UV filtrů v Evropě i ve světě, dále tato látka podléhá poměrně rychlé fotodegradaci na slunci právě za vzniku cisEHMC. Při tomto ději dochází ke zhoršení absorpční schopnosti a jeho ochranná funkce před škodlivým UV zářením klesá. Dalším důvodem byl fakt, že v testech imunotoxicity a estrogenní aktivity, provedených v laboratoři EnTox, vykázala ozářená směs EHMC (obsahující tedy i isomer cis) mnohem vyšší efekty. Rozdílnost odpovědí v testech toxicity a zhoršení ochranné funkce na slunci vede k hypotéze, že cisEHMC by mohl být pro lidský organismus a rovněž i pro životní prostředí (zejména pro vodní organismy) nebezpečnější. V testu genotoxicity na modelu SOS Chromotest nevykázal cisEHMC genotoxický potenciál v žádné z koncentrací. Naproti tomu standard EHMC (SigmaAldrich, CZ) vykázal genotoxický potenciál v nejvyšších zvolených koncentracích 8, 4 a 2 mg.ml¹. Ve všech těchto koncentracích byla překročena limitní hranice IF = 1,5. Tento efekt se potvrdil i v testovaných ozářených směsích obsahující cis i transEHMC, pouze u vyizolovaného samotného cisisomeru tento efekt nebyl pozorován. Nabízí se tedy hypotéza, že genotoxický potenciál látky může být způsoben nečistotami obsaženými ve standardu nebo způsobem výroby této chemické látky. Naproti tomu v testu na modelu UmuC testu byl genotoxický potenciál mírně zvýšený pouze u isomeru cis a to v koncentraci 0,5 mg.ml¹, kdy byl IF = 1,461 ± 0,031, za použití CPRG substrátu. Efekty při použití CPRG byly ve všech koncentracích o něco vyšší než v případě aplikace ONPG substrátu. Lze tedy usuzovat, že v případě látky EHMC je vhodnější použít substrát barvící se do červena, tedy CPRG. Rozdílné odpovědi cis a trans EHMC i v samotných testech genotoxicity vyzývá k dalšímu testování této látky na dalších modelech genotoxicity za použití jiného detekčního systému, například kvasinkového modelu.

Testy na buněčných liniích MVLN a HeLa9903 nevykázaly estrogenní potenciál standardu EHMC (SigmaAldrich, CZ) ani izolovaného isomeru cisEHMC. Přitom v literatuře je uváděno, že EHMC opakovaně vykázal estrogenní potenciál. Je tedy nutné provést podrobnější testy standardu EHMC od výrobce Eusolex, který byl ve všech zmíněných testech potvrzujících estrogenitu používán.

Další oblastí, která by měla být zkoumána je dermální expozice této látce a opět zaměření se na rozdílnosti molekul cisEHMC a transEHMC. EHMC se vyskytuje také ve velké míře ve vodním prostředí. Je známo, že ve vodě tato látka podléhá degradaci rychleji než v jiném rozpouštědle. Je tedy důležité sledovat fotodegradační produkty i v souvislosti s vodními organismy.

Důležitým tématem v navazujících studiích sunscreenů bude ověření penetrace přes lidskou kůži ex vivo metodou Franzovy cely, neboť data týkající se permeační kinetiky se u řady sunscreenů značně liší. Zajímavým výstupem bude také srovnání penetrace isomerních forem a srovnání přestupu přes oholenou a neoholenou kůži.

6.Použitá literatura

AAD. 2003. Solving Problems Related to the Use of Cosmetic and Skin Care Products. September 28, 2003. American Academy of Dermatology. Produced by NetOn-line Services.

Alleyne R. 2010. Vitamin D 'triggers and arms' the immune system. Health News. The Telegraph: http://www.telegraph.co.uk/health/healthnews/7379094/Vitamin-D-triggers-and-arms-the-immune-system.html.

Altenburger R, Bodeker W, Faust M, Grimme LH. 1990. Evaluation of the isobologram method for the assessment of mixtures of chemicals. Combination effect studies with pesticides in algal biotests. Ecotoxicology and Environmental Safety 20(1):98-114.

Ames BN, McCann J, Yamasaki E. 1975. Methods for detecting carcinogens and mutagens with the Salmonella/mammalian-microsome mutagenicity test. Mutation Research 31(6):347-363.

Ashby J, Tinwell H. 1998. Uterotrophic activity of bisphenol A in the immature rat. Environmental Health Perspectives 106(11):719-720.

Ashby J, Tinwell H, Plautz J, Twomey K, Lefevre PA. 2001. Lack of binding to isolated estrogen or androgen receptors, and inactivity in the immature rat uterotrophic assay, of the ultraviolet sunscreen filters Tinosorb M-active and Tinosorb S. Regulatory Toxicology and Pharmacology 34(3):287-291.

Autier P, Dore JF, Schifflers E, Cesarini JP, Bollaerts A, Koelmel KF, Gefeller O, Liabeuf A, Lejeune F, Lienard D and others. 1995. Melanoma and use of sunscreens: an Eortc case-control study in Germany, Belgium and France. International Journal of Cancer 61(6):749-755.

Bachmann BJ. 1972. Pedigrees of some mutant strains of Escherichia coli K-12. Bacteriological Reviews 36(4):525-557.

Benech-Kieffer F, Meuling WJA, Leclerc C, Roza L, Leclaire J, Nohynek G. 2003. Percutaneous absorption of Mexoryl SX (R) in human volunteers: Comparison with in vitro data. Skin Pharmacology and Applied Skin Physiology 16(6):343-355.

Bommannan D, Potts RO, Guy RH. 1990. Examination of stratum corneum barrier function in vivo by infrared spectroscopy. Journal of Investigative Dermatology 95(4):403-408.

Bonin AM, Arlauskas AP, Angus DS, Baker RSU, Gallagher CH, Greenoak G, Brown MML, Meherhomji KM, Reeve V. 1982. UV-absorbing and other sun-protecting substances: genotoxicity of 2-ethylhexyl P-methoxycinnamate. Mutation Research 105(5):303-308.

Bos JD, Meinardi M. 2000. The 500 Dalton rule for the skin penetration of chemical compounds and drugs. Experimental Dermatology 9(3):165-169.

Brown J. 2000. Health Concerns Place Sunscreen Ingredients Under Scrutiny. Chemical Week. p 24.

Chilcott R, Price S. 2008. Principles and Practice of Skin Toxicology. West Sussex: John Wiley & Sons.

Chisvert A, Pascual-Marti MC, Salvador A. 2001. Determination of UV-filters in sunscreens by HPLC. Fresenius Journal of Analytical Chemistry 369(7-8):638-641.

Costin GE, Hearing VJ. 2007. Human skin pigmentation: melanocytes modulate skin color in response to stress. Faseb Journal 21(4):976-994.

Couteau C, Faure A, Fortin J, Paparis E, Coiffard LJM. 2007. Study of the photostability of 18 sunscreens in creams by measuring the SPF in vitro. Journal of Pharmaceutical and Biomedical Analysis 44(1):270-273.

Damiani E, Baschong W, Greci L. 2007. UV-Filter combinations under UV-A exposure: Concomitant quantification of over-all spectral stability and molecular integrity. Journal of Photochemistry and Photobiology B-Biology 87(2):95-104.

Damiani E, Carloni P, Biondi C, Greci L. 2000. Increased oxidative modification of albumin when illuminated in vitro in the presence of a common sunscreen ingredient: Protection by nitroxide radicals. Free Radical Biology and Medicine 28(2):193-201.

De Leeuw SM, Janssen S, Simons J, Lohman PHM, Vermeer BJ, Schothorst AA. 1994. The UV action spectra for the clone-forming ability of cultured human melanocytes and keratinocytes. Photochemistry and Photobiology 59(4):430-436.

Demirpence E, Duchesne MJ, Badia E, Gagne D, Pons M. 1993. MVLN cells: a bioluminescent MCE-7-derived cell line to study the modulation of estrogenic activity. Journal of Steroid Biochemistry and Molecular Biology 46(3):355-364.

Dennis LK, Freeman LEB, VanBeek MJ. 2003. Sunscreen use and the risk for melanoma: A quantitative review. Annals of Internal Medicine 139(12):966-978.

Dokládal M, Páč L. 1995. Anatomie člověka III: Systém kožní, smyslový a nervový. Brno: Masarykova univerzita - fakulta lékařská.

Durrer S, Ehnes C, Fuetsch M, Maerkel K, Schlumpf M, Lichtensteiger W. 2007. Estrogen Sensitivity of Target Genes and Expression of Nuclear Receptor Co-Regulators in Rat Prostate after Pre- and Postnatal Exposure to the Ultraviolet Filter 4-Methylbenzylidene Camphor. Environmental Health Perspectives 115:42-50.

Eliel EL, Wilen SH, Doyle MP. 2001. Basic Organic Stereochemistry: Wiley.

EWG. 2010. Sunscreens Exposed: Nine Surprising Truths. EWG’S 2010 Sunscreen Guide. USA, Washington: http://www.ewg.org/2010sunscreen/.

EWG. 2012a. Nanomaterials and Hormone Disrupters in Sunscreens. EWG's Skin Deep: Sunscreens 2012. USA, Washington: http://www.ewg.org/2012sunscreen/.

EWG. 2012b. Sunscreen exposed: Nine surprising truths. EWG's Skin Deep Sunscreens 2012 USA, Washington: http://www.ewg.org/2012sunscreen/.

Faass O, Schlumpf M, Reolon S, Henseler M, Maerkel K, Durrer S, Lichtensteiger W. 2009. Female sexual behavior, estrous cycle and gene expression in sexually dimorphic brain regions after pre- and postnatal exposure to endocrine active UV filters. Neurotoxicology 30(2):249-260.

FDA. 1999. Sunscreen drug products for over-the-counter human use; final monograph. Food and Drug Administration. Fed Regist 64(98):27666-93.

FDA. 2006. Center for Drug Evaluation and Research Application Number 21-502: Medical Review. Food and Drug Administration.

FDA. 2011. Sunscreen Drug Products for Over-the-Counter Human Use; Final Rules and Proposed Rules. Food and Drug. Federal Register 76(117):35620-35665.

Frank EG, Hauser J, Levine AS, Woodgate R. 1993. Targeting of the UmuD, UmuD', and MucA' mutagenesis proteins to DNA by RecA protein. Proceedings of the National Academy of Sciences of the United States of America 90(17):8169-8173.

Freyberger A, Schmuck G. 2005. Screening for estrogenicity and anti-estrogenicity: a critical evaluation of an MVLN cell-based transactivation assay. Toxicology Letters 155(1):1-13.

Gagliardi L, Amato A, Basili A, Cavazzutti G, Tonelli D. 1987. Determination of sunscreen agents in cosmetic products by supercritical fluid extraction and high-performance liquid chromatography. Journal of Chromatography 408:409-415.

Garland CF, Garland FC, Gorham ED. 2003. Epidemiologic evidence for different roles of ultraviolet A and B radiation in melanoma mortality rates. Annals of Epidemiology 13(6):395-404.

Giokas DL, Salvador A, Chisvert A. 2007. UV filters: From sunscreens to human body and the environment. Trac-Trends in Analytical Chemistry 26(5):360-374.

Godar DE. 1999. UVA1 radiation triggers two different final apoptotic pathways. Journal of Investigative Dermatology 112(1):3-12.

Gomez E, Pillon A, Fenet H, Rosain D, Duchesne MJ, Nicolas JC, Balaguer P, Casellas C. 2005. Estrogenic activity of cosmetic components in reporter cell lines: Parabens, UV screens, and musks. Journal of Toxicology and Environmental Health-Part a-Current Issues 68(4):239-251.

Gonzalez H, Farbrot A, Larko O, Wennberg AM. 2006. Percutaneous absorption of the sunscreen benzophenone-3 after repeated whole-body applications, with and without ultraviolet irradiation. British Journal of Dermatology 154(2):337-340.

Gotthardt I, Schmutzler C, Kirschmeyer P, Wuttke W, Jarry H, Kohrle J. 2007. 4-methylbenzylidene-camphor (4MBC) causes effects comparable to primary hypothyroidism. Experimental and Clinical Endocrinology & Diabetes 115:S59-S59.

Gurtovenko AA, Anwar J. 2007. Modulating the structure and properties of cell membranes: The molecular mechanism of action of dimethyl sulfoxide. Journal of Physical Chemistry B 111(35):10453-10460.

Hanson KM, Gratton E, Bardeen CJ. 2006. Sunscreen enhancement of UV-induced reactive oxygen species in the skin. Free Radical Biology and Medicine 41(8):1205-1212.

Hany J, Nagel R. 1995. Detection of sunscreen agents in human breast milk. Deutsche Lebensmittel-Rundschau 91(11):341-345.

Hayden CGJ, Roberts MS, Benson HAE. 1997. Systemic absorption of sunscreen after topical application. Lancet 350(9081):863-864.

Helmke BM, Mollenhauer J, Herold-Mende C, Benner A, Thome M, Gassler N, Wahl W, Lyer S, Poustka A, Otto HF and others. 2004. BRAF mutations distinguish anorectal from cutaneous melanoma at the molecular level. Gastroenterology 127(6):1815-1820.

Holden C. 2002. Cell biology - Alliance launched to model E-coli. Science 297(5586):1459-1460.

Horák J, Linhart I, Klusoň P. 2004. Úvod do toxikologie a ekologie pro chemiky. Praha: Vysoká škola chemicko-technologická.

Huong SP, Andrieu V, Reynier J-P, Rocher E, Fourneron J-D. 2007. The photoisomerization of the sunscreen ethylhexyl p-methoxy cinnamate and its influence on the sun protection factor. Journal of Photochemistry and Photobiology a-Chemistry 186(1):65-70.

HWN. 2011. Sunscreens - Are They an Oxymoron? Health Worldnet: http://www.healthworldnet.com/articles/heads-or-tails/sunscreens-are-they-an-oxymoron/.

IARC. 2001. IARC Handbook on Cancer Prevention - Sunscreens. France, Lyon: International Agency for Research on Cancer.

ISO. 1997. Determination of the genotoxicity of water and waste water using the umu-test.

Jafry HR, Liga MV, Li QL, Barron AR. 2011. Simple Route to Enhanced Photocatalytic Activity of P25 Titanium Dioxide Nanoparticles by Silica Addition. Environmental Science & Technology 45(4):1563-1568.

Janjua NR, Kongshoj B, Andersson AM, Wulf HC. 2008. Sunscreens in human plasma and urine after repeated whole-body topical application. Journal of the European Academy of Dermatology and Venereology 22(4):456-461.

Janjua NR, Mogensen B, Andersson AM, Petersen JH, Henriksen M, Skakkebaek NE, Wulf HC. 2004. Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans. Journal of Investigative Dermatology 123(1):57-61.

Kanavy HE, Gerstenblith MR. 2011. Ultraviolet Radiation and Melanoma. Seminars in Cutaneous Medicine and Surgery 30(4):222-228.

Kim K, Mueller J, Park YB, Jung HR, Kang SH, Yoon MH, Lee JB. 2011. Simultaneous Determination of Nine UV Filters and Four Preservatives in Suncare Products by High-Performance Liquid Chromatography. Journal of Chromatographic Science 49(7):554-559.

Kimura E, Kawano Y, Todo H, Ikarashi Y, Sugibayashi K. 2012. Measurement of Skin Permeation/Penetration of Nanoparticles for Their Safety Evaluation. Biological & Pharmaceutical Bulletin 35(9):1476-1486.

Klammer H, Schlecht C, Wuttke W, Jarry H. 2005. Multi-organic risk assessment of estrogenic properties of octyl-methoxycinnamate in vivo - A 5-day sub-acute pharmacodynamic study with ovariectomized rats. Toxicology 215(1-2):90-96.

Klinubol P, Asawanonda P, Wanichwecharungruang SP. 2008. Transdermal penetration of UV filters. Skin Pharmacology and Physiology 21(1):23-29.

Kobayashi M, Kalriess W. 1997. Photocatalytic Activity of Titanium Dioxide and Zinc Oxide. Cosmetics & Toiletries^® magazine 112(83):83-85.

Kroutil J. 2005. Problémy ve stereochemii uhlíkatých sloučenin. Sborník textů přednášek letního semináře 2005. Nové Hrady: http://archiv.otevrena-veda.cz/.

Lademann J, Weigmann HJ, Rickmeyer C, Barthelmes H, Schaefer H, Mueller G, Sterry W. 1999. Penetration of titanium dioxide microparticles in a sunscreen formulation into the horny layer and the follicular orifice. Skin Pharmacology and Applied Skin Physiology 12(5):247-256.

Little JW, Mount DW. 1982. The SOS regulatory system of Escherichia coli. Cell 29(1):11-22.

Liu T, Wu D. 2011. Simultaneous determination of some ultraviolet-absorbing chemicals in sunscreen cosmetics using a high-performance liquid chromatography method. International Journal of Cosmetic Science 33(5):408-415.

Lowe NJ. 1998. Photoprotection. Hawk JLM (ed): Photodermatology. London: Chapman & Hall. .213-221.

Lucova M, Hojerova J, Pazourekova S, Klimova Z. 2013. Absorption of triphenylmethane dyes Brilliant Blue and Patent Blue through intact skin, shaven skin and lingual mucosa from daily life products. Food and Chemical Toxicology 52:19-27.

Lund LP, Timmins GS. 2007. Melanoma, long wavelength ultraviolet and sunscreens: Controversies and potential resolutions. Pharmacology & Therapeutics 114(2):198-207.

Ma RS, Cotton B, Lichtensteiger W, Schlumpf M. 2003. UV filters with antagonistic action at androgen receptors in the MDA-kb2 cell transcriptional-activation assay. Toxicological Sciences 74(1):43-50.

Madigan MM, Martinko JM. 2006. Brock Biology of microorganisms (11th ed.). Pearson. ISBN 0-13-196893-9.

Maerkel K, Durrer S, Henseler M, Schlumpf M, Lichtensteiger W. 2007. Sexually dimorphic gene regulation in brain as a target for endocrine disrupters: Developmental exposure of rats to 4-methylbenzylidene camphor. Toxicology and Applied Pharmacology 218(2):152-165.

Matsumura Y, Ananthaswamy HN. 2004. Toxic effects of ultraviolet radiation on the skin. Toxicology and Applied Pharmacology 195(3):298-308.

Mavon A, Miquel C, Lejeune O, Payre B, Moretto P. 2007. In vitro percutaneous absorption and in vivo stratum corneum distribution of an organic and a mineral sunscreen. Skin Pharmacology and Physiology 20(1):10-20.

Mead MN. 2008. Benefits of sunlight: A bright spot for human health. Environmental Health Perspectives 116(4):A160-A167.

Meysman P, Sánchez-Rodríguez A, Fu Q, Marchal K, Engelen K. 2013. Expression Divergence between Escherichia coli and Salmonella enterica serovar Typhimurium Reflects Their Lifestyles. Molecular Biology and Evolution [Epub ahead of print].

Miletín M. 2011. Means of skin protection against harmful effects of UV radiation. Praktické lékarenství 7(1):34-38.

Moan J, Dahlback A, Setlow RB. 1999. Epidemiological support for an hypothesis for melanoma induction indicating a role for UVA radiation. Photochemistry and Photobiology 70(2):243-247.

Monhaphol T, Albinsson B, Wanichwecharungruang SP. 2007. 2-Ethylhexyl-2,4,5-trimethoxycinnamate and di-(2-ethylhexyl)-2,4,5-trimethoxybenzalmalonate as novel UVA filters. Journal of Pharmacy and Pharmacology 59(2):279-288.

Moustacchi E. 2000. DNA damage and repair: consequences on dose-responses. Mutation Research-Genetic Toxicology and Environmental Mutagenesis 464(1):35-40.

Murov S, Carmichael I, Hug GL. 1993. Handbook of Photochemistry. United States: Marcel Dekker Inc.

Nagtegaal M, Ternes Ta, Baumann W, Nagel R. 1997. UV-Filtersubstanzen in Wasser und Fischen. UWSF-Z Umweltchem Ökotox 9(2):79-86.

Nakamura S, Oda Y, Ugawa M. 1990. Induction of umu gene expression in Salmonella typhimurium TA1535/pSK1002 by dimethyl sulfoxide (DMSO). Mutation Research 229(1):11-15.

Narayanan DL, Saladi RN, Fox JL. 2010. Ultraviolet radiation and skin cancer. International Journal of Dermatology 49(9):978-986.

Negreira N, Rodriguez I, Rubi E, Cela R. 2011. Optimization of pressurized liquid extraction and purification conditions for gas chromatography-mass spectrometry determination of UV filters in sludge. Journal of Chromatography A 1218(2):211-217.

Nishimura K, Hashimoto Y, Iwasaki S. 1994. (S)-form of alpha-methyl-N(alpha)-phthalimidoglutarimide, but not its (R)-form, enhanced phorbol ester-induced tumor necrosis factor-alpha production by human leukemia cell HL-60: implication of optical resolution of thalidomidal effects. Chemical & Pharmaceutical Bulletin 42(5):1157-1159.

NTP. 1992. 2-Hydroxy-4-methoxybenzophenone, NTP Toxicity Report Number 21. USA, North Carolina: http://ntp.niehs.nih.gov/ntp/htdocs/ST_rpts/tox021.pdf.

NTP. 2008. NTP Research Concept: 2-Ethylhexyl p-Methoxycinnamate. USA, North Carolina: http://ntp.niehs.nih.gov/ntp/Noms/Final_ResConcept/EHMC.pdf.

NTP. 2012a. NTP Report of the Assessment of Contact Hypersensitivity to 2-Ethylhexyl p-methoxycinnamate in Female BALB/c Mice. USA, North Carolina: http://ntp.niehs.nih.gov/?objectid=DDFBCFBD-B3AB-DB77-50A58DE5C88248E0.

NTP. 2012b. Photocarcinogenesis Studies of Retinoic Acid and Retinyl Palmitate in SKH-1 Mice (simulated solar light and topical application study). USA, North Carolina.

Oda Y, Nakamura S, Oki I, Kato T, Shinagawa H. 1985. Evaluation of the new system (umu-test) for the detection of environmental mutagens and carcinogens. Mutation Research 147(5):219-229.

Odum J, Lefevre PA, Tittensor S, Paton D, Routledge EJ, Beresford NA, Sumpter JP, Ashby J. 1997. The rodent uterotrophic assay: Critical protocol features, studies with nonyl phenols, and comparison with a yeast estrogenicity assay. Regulatory Toxicology and Pharmacology 25(2):176-188.

Oguchi-Fujiyama N, Miyazawa K, Kikuchi A, Yagi M. 2012. Photophysical properties of dioctyl 4-methoxybenzylidenemalonate: UV-B absorber. Photochemical & Photobiological Sciences 11(10):1528-1535.

Ono A. 2012. Stably Transfected Estrogen Receptor Alpha Transactivation Assay Using HeLa9903 Cell Line as In Vitro Method to Screen the Endocrine Disruption Potentials of Chemicals. In Vitro Cellular & Developmental Biology-Animal 48:13-13.

Pattanaargson S, Munhapol T, Hirunsupachot N, Luangthongaram P. 2004. Photoisomerization of octyl methoxycinnamate. Journal of Photochemistry and Photobiology a-Chemistry 161(2-3):269-274.

PLOS. 2005. A Novel Data-Mining Approach Systematically Links Genes to Traits. PLoS Biol 3(5):e166.

Pye SR, Vanderschueren D, O'Neill TW, Lee DM, Jans I, Billen J, Gielen E, Laurent M, Claessens F, Adams JE and others. 2012. Active vitamin D (1,25-dihydroxyvitamin D) and bone health in middle-aged and elderly men: the European Male Aging Study. Rheumatology 51:103-104.

Quillardet P, Huisman O, Dari R, Hofnung M. 1982. SOS chromotest, a direct assay of induction of an SOS function in Escherichia coli K-12 to measure genotoxicity. Proceedings of the National Academy of Sciences of the United States of America-Biological Sciences 79(19):5971-5975.

Rachon D, Rimoldi G, Wuttke W. 2006. In vitro effects of benzophenone-2 and octyl-methoxycinnamate on the production of interferon-gamma and interleukin-10 by murine splenocytes. Immunopharmacology and Immunotoxicology 28(3):501-510.

Rajagopalan M, Lu C, Woodgate R, Odonnell M, Goodman MF, Echols H. 1992. Activity of the purified mutagenesis proteins UmuC, UmuD', and RecA in replicative bypass of an abasic DNA lesion by DNA polymerase III. Proceedings of the National Academy of Sciences of the United States of America 89(22):10777-10781.

Rameš J, Bencko V. 1993. Ultraviolet rays and their biological effects. Časopis lékařů českých 132(5):129-133.

Rastogi SC. 2002. UV filters in sunscreen products - a survey. Contact Dermatitis 46(6):348-351.

Ro KW, Choi JB, Lee MH, Kim JW. 1994. Determination of salicylate- and benzophenone-type sunscreen agents in cosmetic products by gas chromatography-mass spectrometry. Journal of Chromatography A 688(1-2):375-382.

Roberts JJ, Friedlos F. 1987. Differential toxicity of cis- and trans-diamminedichloroplatinum(II) toward mammalian cells: lack of influence of any difference in the rates of loss of their DNA-bound adducts. Cancer Research 47(1):31-36.

Rodil R, Moeder M, Altenburger R, Schmitt-Jansen M. 2009. Photostability and phytotoxicity of selected sunscreen agents and their degradation mixtures in water. Analytical and Bioanalytical Chemistry 395(5):1513-1524.

Rodriguez E, Valbuena MC, Rey M, de Quintana LP. 2006. Causal agents of photoallergic contact dermatitis diagnosed in the national institute of dermatology of Colombia. Photodermatology Photoimmunology & Photomedicine 22(4):189-192.

Roggen EL, Soni NK, Verheyen GR. 2006. Respiratory immunotoxicity: An in vitro assessment. Toxicology in Vitro 20(8):1249-1264.