The importance of the depth distribution of melanin in skin for DNA protection and other photobiological processes

Nielsen, Kristian Pagh; Zhao, Lu; Stamnes, Jakob J.; Stamnes, Knut; Moan, Johan Emelian

doi:10.1016/j.jphotobiol.2005.11.008

Cited by 83 publications

(56 citation statements)

References 12 publications

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“…Melanin, found in human skin, is considered to be protective against UV and ionising radiation (Nielsen et al, 2006). Darkly pigmented skin contains more melanin than lightly pigmented skin.…”

Section: Discussionmentioning

confidence: 99%

“…Skin pigmentation depends on the amount and distribution of a ubiquitous pigment known as melanin (Nielsen et al, 2006). The skin of darkly pigmented individuals contains larger amounts of melanin, present as granules in melanocytes, resulting in a darker skin tone.…”

mentioning

confidence: 99%

“…The skin of darkly pigmented individuals contains larger amounts of melanin, present as granules in melanocytes, resulting in a darker skin tone. Melanin protects human skin from ultraviolet (UV) and ionising radiation damage through its capacity to absorb light over a broad spectrum (Nielsen et al, 2006). Despite the protective capacity of melanin, both UV and ionising radiation can cause irreparable skin damage.…”

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confidence: 99%

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Post-treatment skin reactions reported by cancer patients differ by race, not by treatment or expectations

et al. 2007

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Cancer patients may experience skin problems while undergoing chemotherapy and radiation therapy. Frequency of skin reactions may be influenced by skin pigmentation and psychological factors. A Symptom Inventory completed by 656 cancer patients nationwide before and after chemotherapy, radiation therapy, or chemotherapy plus radiation therapy was analysed to determine if treatment type, race (Black vs White), and pretreatment expectations influenced post-treatment skin reactions. Subsequent analysis of a local Symptom Inventory completed weekly for 5 weeks by 308 patients receiving radiation therapy examined severity of reported skin reactions. Significantly more patients receiving radiation therapy had stronger expectations of skin problems (62%) than patients receiving chemotherapy (40%, P ¼ 0.001) or chemotherapy plus radiation therapy (45%, P ¼ 0.003). Overall, expectations did not correlate with patient reported post-treatment skin problems in white (r ¼ 0.014, P ¼ 0.781) or black (r ¼ 0.021, P ¼ 0.936) patients. Although no significant difference was found between black and white patients in their pretreatment expectations of skin problems (P ¼ 0.32), black patients (10 out of 18, 56%) reported more skin problems than white patients (90 out of 393, 23%, P ¼ 0.001). Similarly, the local study showed that significantly more black patients (1 out of 5, 20%) reported severe skin reactions at the treatment site than white patients (12 out of 161, 8%). A direct correlation was observed between severity of skin problems and pain at the treatment site (r ¼ 0.541, Po0.001). Total radiation exposure did not significantly correlate with the report of skin problems at the treatment site for white or black patients. Overall, black patients reported more severe post-treatment skin problems than white patients. Our results suggest that symptom management for post-treatment skin reactions in cancer patients receiving radiation treatment could differ depending on their racial background.

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Section: Discussionmentioning

confidence: 99%

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Post-treatment skin reactions reported by cancer patients differ by race, not by treatment or expectations

et al. 2007

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“…In untanned skin most of the melanin is located in the basal layer, while it is distributed throughout the entire epidermis in tanned skin. Not only the amount of melanin, but also its distribution in the epidermis has a huge impact on how much UV light is actually reaching the living cells (for DNA damage and vitamin D production), while the degradation of folate in the dermal blood (deeper than the epidermis) will be more or less independent of the distribution of melanin within the epidermis [113].…”

Section: Melanin and Melanosomesmentioning

confidence: 99%

“…A large number of larger melanosomes in the stratum corneum of higher skin types yield a higher scattering coefficient, and also with a more forward directed angular distribution. Thus they contribute to a higher light attenuation as compared with lighter skin, with much smaller melanin particles in this outer layer of the epidermis [113]. Interestingly, melanin scattering increases diffuse 19 reflectance below 300 nm in highly pigmented skin with large melanosomes in the stratum corneum, as compared with skin with less pigmentation [118].…”

Section: Melanin and Melanosomesmentioning

confidence: 99%

Solar radiation and human health

Moan

Juzeniene

2010

Journal of Photochemistry and Photobiology B: Biology

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The Sun has played a major role in the development of life on Earth. In Western culture, people are warned against Sun exposure because of its adverse effects: erythema, photoimmunosuppression, photoageing, photocarcinogenesis, cataracts and photokeratitis. However, Sun exposure is also beneficial, since moderate doses give beneficial physiological effects: vitamin D synthesis, reduction of blood pressure and mental health. Shortage of Sun exposure may be even more dangerous to human health than excessive exposure. Avoiding Sun exposure leads to vitamin D deficiency which is associated not only with rickets and osteomalacia, but also with increased risk of cardiovascular disease, multiple sclerosis, rheumatoid arthritis, diabetes, influenza, many types of cancer and adverse pregnancy outcomes. Solar radiation induces nitric oxide release in tissue and immediate pigment darkening which certainly play important roles, although these are still unknown. Action spectra relevant for health are described. We will also review what is known about spectral and intensity variations of terrestrial solar radiation as well as its penetration through the atmosphere and into human skin and tissue.

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