Since ages, the skin colour is an important issue for human race. Melanocyte abnormalities are mentioned during the fetal developmental stages in literature from ancient cultures. The deciding factor for the pigmentation is melanin. An old notion of melanocyte producing melanin is now obsolete. It is the epidermal unit which is responsible for the process of melanogenesis, production and distri...

Topica! tyrosine has been proposed as a tanning accelerator because tyrosine is a precursor of melanin. We tested formulations containing O, 1, and 2% L-tyrosine topically on 14 individuals daily for 28 days. Percutaneous absorption using "C tyrosine was 1.23% in 24 hr. No enhanced pigmentation was clinically evident in any of the subjects. In this study, we were unable to demonstrate that topi...

The behaviour during an exploration task and the response to a confinement stress of Arctic charr Salvelinus alpinus were evaluated. Behaviour of individuals during 90 min of exploration was classified into high and low activity. High-activity individuals had higher plasma cortisol levels following stress compared to low-activity individuals. This indicates that high- and low-activity individua...

ELANIN PIGMENTATION has aroused the curiosity and attention of man since the beginning of recorded history. This interest stems in part from the social, protective and cosmetic significance of pigmentation. In addition, much interest has arisen concerning the possible role of melanin formation in the development of the melanoma which has been described as having the most sinister reputation of ...

The relationship between cell pigmentation and radiosensitivity was investigated in two selected human melanoma cell lines with different melanin content (mixed type: eumelanin and pheomelanin, and pheomelanotic phenotypes). The same study was also done after stimulation of melanogenesis (1) by addition of the melanin precursor l-tyrosine to each of the cell lines separately and (2) by irradiat...

Cells secrete extracellular vesicles (EVs), exosomes and microvesicles, which transfer proteins, lipids and RNAs to regulate recipient cell functions. Skin pigmentation relies on a tight dialogue between keratinocytes and melanocytes in the epidermis. Here we report that exosomes secreted by keratinocytes enhance melanin synthesis by increasing both the expression and activity of melanosomal pr...

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...

Melanins are natural pigments distributed in living organisms and they are responsible for pigmentation of surface structure. In the present work, gel exclusion chromatography, spectrophotometric, and dielectric relaxation techniques were used to characterize DOPA melanin before and after irradiation with 60 Co gamma rays in the range of 5 to 50 Gy. The results show that the studied melanin is ...

BACKGROUND Although clinical melanin pigmentation does not present itself as a medical problem or a disease entity, "black gums" is a major esthetic complaint for many people, who often requests cosmetic corrections. Gingival depigmentation can be carried out using many procedures; lasers of various types being a new addition. This study was undertaken to evaluate and compare the effectiveness ...

Tristimulus colorimetry and diffuse reflectance spectroscopy (DRS) are white-light skin reflectance techniques used to measure the intensity of skin pigmentation. The tristimulus colorimeter is an instrument that measures a perceived color and the DRS instrument measures biological chromophores of the skin, including oxy- and deoxyhemoglobin, melanin and scattering. Data gathered from these too...