Medical research

Sunlight continues to damage skin in the dark

Much of the damage that ultraviolet radiation (UV) does to skin occurs hours after sun exposure, a team of Yale-led researchers concluded in a study that was published online Feb. 19 by the journal Science.

Other

Laser treatment can make your brown eyes blue

Just like the old Crystal Gayle song, a new laser technology could soon allow you to turn those boring brown eyes of your to a rich and beautiful blue. But you better make sure that blue eyes are what you really want because ...

Diseases, Conditions, Syndromes

Vitiligo treated successfully with arthritis drug and light therapy

Building on prior research that examined the use of an arthritis medication to treat vitiligo, a team of Yale dermatologists has successfully applied a novel combination therapy—the medication and light—to restore skin ...

Oncology & Cancer

Newly identified gene mutation adds to melanoma risk

A major international study has identified a novel gene mutation that appears to increase the risk of both inherited and sporadic cases of malignant melanoma, the most deadly form of skin cancer. The identified mutation occurs ...

Psychology & Psychiatry

Is this peptide a key to happiness?

(Medical Xpress)—What makes us happy? Family? Money? Love? How about a peptide? The neurochemical changes underlying human emotions and social behavior are largely unknown. Now though, for the first time in humans, scientists ...

Oncology & Cancer

Photoacoustic device finds cancer cells before they become tumors

Early detection of melanoma, the most aggressive skin cancer, is critical because melanoma will spread rapidly throughout the body. Now, University of Missouri researchers are one step closer to melanoma cancer detection ...

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Melanin

Melanin i/ˈmɛlənɪn/ (Greek: μέλας, black) is a pigment that is ubiquitous in nature, being found in most organisms (spiders are one of the few groups in which it has not been detected). In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms. All melanins can be considered as derivatives of polyacetylene, since they rely on a polyconiugate structure. Another common form of melanin is pheomelanin, a red-brown polymer of benzothiazine units largely responsible for red hair and freckles. The presence of melanin in the archaea and bacteria kingdoms is an issue of ongoing debate among researchers in the field.

The increased production of melanin in human skin is called melanogenesis. Production of melanin is stimulated by DNA damage induced by UVB-radiation, and it leads to a delayed development of a tan. This melanogenesis-based tan takes more time to develop, but it is long-lasting.

The photochemical properties of melanin make it an excellent photoprotectant. It absorbs harmful UV-radiation (ultraviolet) and transforms the energy into harmless heat through a process called "ultrafast internal conversion". This property enables melanin to dissipate more than 99.9% of the absorbed UV radiation as heat (see photoprotection). This prevents the indirect DNA damage that is responsible for the formation of malignant melanoma and other skin cancers.

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