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Cutaneous Photosensitization
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
A convenient source for most phototoxic compounds activated by light in the UVA spectral band is the blacklight fluorescent lamp. These lamps provide a broad band output in the UVA region centered around 350 nm. A pane of glass interposed between the source and the target will eliminate the small amount of UVB emitted by these lamps. Several lamps separated by 5 to 10 cm and mounted 15 to 20 cm above the upper surface of the agar are required for effective radiation intensity. A variety of instruments are available for measuring the intensity of the radiation at the agar surface. This method is especially sensitive to the psoralen compounds and coal tar derivatives used in dermatology. It also can be used for the presumptive identification of plants causing phytophotodermatitis.
Noninvasive Tests
Published in Vineet Relhan, Vijay Kumar Garg, Sneha Ghunawat, Khushbu Mahajan, Comprehensive Textbook on Vitiligo, 2020
Hemant Kumar Kar, Gunjan Verma
The Woods lamp emits long-wave UV radiation (UVR), also called black light, generated by a high pressure mercury arc fitted with a compound filter made of barium silicate with 9% nickel oxide, the “Woods filter.” This filter is opaque to all light rays except a band between 320 and 400 nm with a peak at 365 nm. Fluorescence of tissues occurs when Woods (UV) light is absorbed and radiation of a longer wavelength, usually visible light, is emitted. The output of Woods lamp is generally low (<1 mw/cm2). The fluorescence of normal skin is very faint or absent and is mainly due to constituents of elastin, aromatic amino acids, and precursors or products of melanin [1,8].
Animal Models for Phototoxicity Testing
Published in Francis N. Marzulli, Howard I. Maibach, Dermatotoxicology Methods: The Laboratory Worker’s Vade Mecum, 2019
Lark A. Lambert, Wayne G. Warner, Andrija Kornhauser
Lovell and Sanders (1992) used fluorescent black lights with an irradiance of approximately 18 W/m2. The animals received UVA doses of 7.5–20 J/cm2. The Nilsson et al. (1993) study used 6 different light sources, including fluorescent black lights and solar simulators, with irradiances of 14–50 W/m2 in the UVA spectral region, and doses of UVA ranging from 9 to 10 J/cm2. Some protocols included UVB light at doses of 0.1–0.3 J/cm2. Care must be taken to avoid unnecessary injury or pain to the animals caused by excessive heat, especially from the more intense solar simulators.
Modification of the training environment to improve functional performance using blacklight conditions: a case study of a child with autism
Published in International Journal of Developmental Disabilities, 2020
Seyed Alireza Derakhshanrad, Emily Piven
Since Mary showed no visual attention to objects in her environment other than popcorn, the occupational therapist decided to alter the visual environment to affect change. This turned out to be a logical environmental modification that increased Mary’s attention to objects in the foreground. Blacklight conditions heightened her focus on objects that became florescent against the black background. The fact that Mary’s functional performance improved through optimizing the visual environment corroborated the findings of Little et al. (2018) who also found that modifications of the task and lighting in the training environment might improve visual processing of children with autism. The blacklight facilitated interaction with various objects in a purposeful way. The occupational therapist worked with the psychologist to develop an operant conditioning program to reinforce interaction with objects in the environment, which was deleted as soon as Mary began to link pictures with objects and construct chains of “Popit Beads,” thus showing intrinsic motivation and engagement in the visual task.
Natural options for management of melasma, a review
Published in Journal of Cosmetic and Laser Therapy, 2018
Analysis of melasma is essential as it informs the treatment choice. There are few instruments that are used for melasma analysis. These include Wood’s lamp, dermoscopy, reflectance confocal microscopy, colimetry, mexametry, Melasma Area and Severity Index, and histology. Wood’s lamp examination is the most common melasma grading tool in which the skin is examined while exposed to the black light emitted by Wood’s lamp. This diagnostic tool was invented by a Caltimore physicist, Robert W. Wood, in 1903. Black light is invisible to the naked eye because it is in the UV spectrum with a wavelength just shorter than the color violet. The Wood’s lamp glows violet in a dark environment because it also emits some light in the violet part of the electromagnetic spectrum. A traditional Wood’s lamp is a low-output mercury arc covered by a Wood filter (barium silicate and 9% nickel oxide) and emits wavelength 320–450 nm (peak 365 nm). Wood’s lamp highlights the difference in pigmentation between affected and normally skin. Intensely seen pigmentation under this lamp responds better to topical treatment (39,40).