|
|
10th
International Inter University Scientific Meeting
Academy of Studenica
PERSPECTIVES
IN MELANOMA MANAGEMENT
& NANOTECHNOLOGY IN BIOMEDICINE
Organizers:
Institute of Oncology
Sremska Kamenica; Union of Cancer Prevention
Societies of Vojvodina, Novi Sad; Clinic of Oncology, Nis; Institute
for Oncology and Radiology of Serbia, Belgrade Center for Bioengineering,
Faculty of Mechanical Engineering, University of Belgrade
President:
Vladimir Baltic Vice-presidents: Zlata
Janjic, Radan Dzodic, Borislava Nikolin; Djuro Koruga
|
|
|
| |
ULTRAVIOLET
RADIATION AND MELANOGENESIS
Stanojević
M, *Stanojević Z, Jovanović D, **Stojiljković M.
Clinic of
Dermatovenerology, Clinical Centre Niš, Niš, Serbia and Montenegro
* Clinic of Oncology, Clinical Centre Niš,
Niš, Serbia and Montenegro
** Faculty of Medicine, University of Niš,
Niš, Serbia and Montenegro
|
|
| |
ABSTRACT
Light
radiation is a part of the electromagnetic radiation, and it consists
of the ultraviolet (UV) radiation (8,3%), visible light (38,9%)
and infrared radiation (52,8%) (1). UV radiation is biologically
most active. UV radiation has the photon energies in the range 3,1-12,4
eV and wave-lengths in the range 100-400 nM (3,4). UV radiation
energy is absorbed in the form of photons in biomolecules (chromophores)
and induces various cellular reactions, out of which photochemical
and photosensitizating are most significant (2). Depth of skin penetration
of UV rays increases with wave-length. In contact with the skin
UV radiation incites protection mechanisms out of which the most
important are stratum corneum thickening and melanin synthesis (melanogenesis)
(10,11). Three melanin types are synthesized: eumelanin, pheomelanin
and neuromelanin. Melanin synthesis commences with the entry of
tyrosine into melanocytes. Enzyme tyrosinase (TRP-1 and TRP-2) catalizes
tyrosine into dihydroxyphenilalanin DOPA and DOPA chinon, which
is by further oxidation transformed into eumelanin (19,20). Melanin
is deposited within melanosomes and it is transported into keratinocytes
by direct fusion of keratinocyte membrane and dendritic melanocyte
projections (16,21). Basic role of melanin is absorbtion and scattering
of UV rays and neutralization of free radicals. UV radiation incites
skin pigmentation by melanogenesis stimulation, which occurs immediately
as well as a delayed phenomenon. Cell cycle prolongation in the
G1 phase is the mechanism by which skin cells protect themselves
from UV radiation, while UV-induced DNA damage reparation is completed
(30). |
-
|
| |
Keywords:
UV radiation, Melanogenesis |
|
|
