Vitiligo is sometimes complicated with psoriasis, and more frequently, pigmentation or depigmentation arises after psoriatic lesion subsides. It not clear whether melanocyte function maintained in which characterized by keratinocyte proliferation, how melanin migration to keratinocytes affected, we will discuss the behavior of pigment cells psoriasis lesions. Melanin-containing were observed ma...

Skin hyperpigmentation disorders due to abnormal melanin production induced by ultraviolet (UV) irradiation are both a clinical and cosmetic problem. UV irradiation stimulates melanin production in melanocytes by increasing intracellular cAMP. Expression of heat shock proteins (HSPs), especially HSP70, is induced by various stressors, including UV irradiation, to provide cellular resistance to ...

Iridescent coloration plays an important role in the visual communication system of many animal taxa. It is known that iridescent structural colours result from layers of materials with different refractive indexes, which in feathers usually are keratin, melanin and air. However, the role of these materials in the production of structural iridescent coloration is still poorly documented. Despit...

PURPOSE It has been suggested that macular pigment (MP) and melanin may protect against age-related maculopathy (ARM). To check this, MP and melanin optical density were measured in a random population-based sample of subjects 55 years of age or older. METHODS Spectral fundus reflectance of the fovea was measured in one eye per subject in a 2.3 degrees detection field with a fundus reflectome...

Exposure of human skin to solar ultraviolet radiation (UVR), a powerful carcinogen [1] comprising ~95% ultraviolet A (UVA) and ~5% ultraviolet B (UVB) at the Earth's surface, promotes melanin synthesis in epidermal melanocytes [2, 3], which protects skin from DNA damage [4, 5]. UVB causes DNA lesions [6] that lead to transcriptional activation of melanin-producing enzymes, resulting in delayed ...

Sphingosine-1-phosphate (S1P) has emerged as a bioactive lipid modulator that mediates a variety of cell functions. However, the effects of S1P on melanogenesis are not well known. Therefore, we investigated the actions of S1P on melanin synthesis using a spontaneously immortalized mouse melanocyte cell line, Mel-Ab. This study shows that S1P significantly inhibits melanin synthesis in a concen...

The human fungal pathogen Cryptococcus neoformans produces melanin in the presence of various substrates, including the L enantiomer of 3,4-dihydroxyphenylalanine (DOPA). The enzyme laccase catalyses the formation of melanin by oxidizing L-DOPA, initiating a series of presumably spontaneous reactions that ultimately leads to the polymerization of the pigment in the yeast cell wall. There, melan...

There is a need for radioprotectors that protect normal tissues from ionizing radiation in patients receiving high doses of radiation and during nuclear emergencies. We investigated the possibility of creating an efficient oral radioprotector based on the natural pigment melanin that would act as an internal shield and protect the tissues via Compton scattering followed by free radical scavengi...

Melanins are enigmatic pigments found in all biological kingdoms that are associated with a variety of functions, including microbial virulence. Despite being ubiquitous in nature, melanin pigments have long resisted atomic-level structural examination because of their insolubility and amorphous organization. Cryptococcus neoformans is a human pathogenic fungus that melanizes only when provided...

Many animals develop bold patches of black or brown coloration that are derived from melanin pigments and serve as sexual or social signals. At present, there is much debate among behavioral ecologists over whether melanin-based color signals are costly to produce. Studies that have manipulated crude aspects of nutrition (i.e., total food intake) or health have generally found melanin-based plu...