BACKGROUND/AIMS: The accuracy and reliability of any method to assess the UVA protection effectiveness of sunscreens needs to be demonstrated. The aim of the present study was to calibrate the effectiveness of a biological end point (Persistent Pigment Darkening, PPD) to assess UVA photoprotection, METHODS: Persistent Pigment Darkening was selected as the end point because its action spectrum extends across the UVA. A broad UVA source was chosen to challenge all UVA wavelengths. Attenuation of UVA was performed with neutral density filters (equally absorbing at all wavelengths). Human subjects were tested with a series of UVA beams attenuated by the neutral density filters. The UVA protection effectiveness of a standard sunscreen was also tested with four panels of volunteers to assess the reproducibility of the method. RESULTS: The attenuation factors of the neutral density filters were found to correspond to the UVA protection factors arrived at with PPD as the end point. The repetitive tests showed a good internal consistency of the method. CONCLUSIONS: The calibration procedure proposed shows threshold PPD, used as an end point in a UVA-PF test method, to be a reliable endogenous dosimeter for UVA radiation that enters the skin.
BACKGROUND/AIMS: The accuracy and reliability of any method to assess the UVA protection effectiveness of sunscreens needs to be demonstrated. The aim of the present study was to calibrate the effectiveness of a biological end point (Persistent Pigment Darkening, PPD) to assess UVA photoprotection, METHODS: Persistent Pigment Darkening was selected as the end point because its action spectrum extends across the UVA. A broad UVA source was chosen to challenge all UVA wavelengths. Attenuation of UVA was performed with neutral density filters (equally absorbing at all wavelengths). Human subjects were tested with a series of UVA beams attenuated by the neutral density filters. The UVA protection effectiveness of a standard sunscreen was also tested with four panels of volunteers to assess the reproducibility of the method. RESULTS: The attenuation factors of the neutral density filters were found to correspond to the UVA protection factors arrived at with PPD as the end point. The repetitive tests showed a good internal consistency of the method. CONCLUSIONS: The calibration procedure proposed shows threshold PPD, used as an end point in a UVA-PF test method, to be a reliable endogenous dosimeter for UVA radiation that enters the skin.
Authors: Sérgio Schalka; Denise Steiner; Flávia Naranjo Ravelli; Tatiana Steiner; Aripuanã Cobério Terena; Carolina Reato Marçon; Eloisa Leis Ayres; Flávia Alvim Sant'anna Addor; Helio Amante Miot; Humberto Ponzio; Ida Duarte; Jane Neffá; José Antônio Jabur da Cunha; Juliana Catucci Boza; Luciana de Paula Samorano; Marcelo de Paula Corrêa; Marcus Maia; Nilton Nasser; Olga Maria Rodrigues Ribeiro Leite; Otávio Sergio Lopes; Pedro Dantas Oliveira; Renata Leal Bregunci Meyer; Tânia Cestari; Vitor Manoel Silva dos Reis; Vitória Regina Pedreira de Almeida Rego Journal: An Bras Dermatol Date: 2014 Nov-Dec Impact factor: 1.896
Authors: Indermeet Kohli; Rubina Shafi; Prescilia Isedeh; James L Griffith; Mohammed S Al-Jamal; Narumol Silpa-Archa; Bradford Jackson; Mohammed Athar; Nikiforos Kollias; Craig A Elmets; Henry W Lim; Iltefat H Hamzavi Journal: J Am Acad Dermatol Date: 2017-03-22 Impact factor: 11.527
Authors: Sergio G Coelho; Yanchun Zhou; Harry F Bushar; Sharon A Miller; Barbara Z Zmudzka; Vincent J Hearing; Janusz Z Beer Journal: Pigment Cell Melanoma Res Date: 2009-02-17 Impact factor: 4.693
Authors: Sergio G Coelho; Wonseon Choi; Michaela Brenner; Yoshinori Miyamura; Yuji Yamaguchi; Rainer Wolber; Christoph Smuda; Jan Batzer; Ludger Kolbe; Shosuke Ito; Kazumasa Wakamatsu; Barbara Z Zmudzka; Janusz Z Beer; Sharon A Miller; Vincent J Hearing Journal: J Investig Dermatol Symp Proc Date: 2009-08