Becker's nevus or Becker's melanosis is a distinct clinical entity in which epimal thickening may be minimal and hairiness and pigmentation obvious. 1Ne report a case of 14-year-old female suffering from Beckers melanosis with multiple and extensive skin lesions. The electron microscope revealed that the melanocytes were bulky with increased melanogenesis and an increased number of melanosomes was found in the keratinocytes. In addition, a large number of melanosomes were seen individually in the keratinocytes.
Adolescent ; Female ; Humans ; Keratinocytes ; Melanocytes ; Melanosis ; Melanosomes ; Nevus* ; Pigmentation ; Skin

No abstract available.
Humans* ; Melanocytes* ; Tretinoin*

No abstract available.
Hair* ; Melanocytes* ; Nevus, Halo*

BACKGROUND: The growth of cells is closely related to components in a culture medium. There are many reports about cellular characteristics of melanocytes grown in a PMA-contained medium. However, only a few reports have been studied by using a physiologic mitogens-contained medium. To understand melanocyte in vivo, it is necessary to know the cellular biology of melanocytes grown in a physiologic mitogens-contained medium. OBJECTIVE: To investigate any differences between melanocytes grown in phorbol 12-myristate 13-acetate(PMA)-contained medium and in physiologic mitogens-contained medium. METHOD: We examined morphology, number and melanin contents of cultured human melanocytes grown in a PMA-contained medium and physiologic mitogens-, such as bFGF, ET-1 and a a-MSH contained medium. Result : The results are summarized as follows : 1. There were no significant morphologic differences between cells in PMA-contained medium and in physiologic mitogens-contained medium. 2. The number of melanocytes were significantly more numerous in PMA-contained medium on the 2nd day (p<0.05), but significantly less numerous in the same medium on the 6th day (p<0.05). So, the proliferation rate of melanocytes in PMA-contained medium became lower than in physiologic mitogens-contained medium as time went by. 3. Melanocytes grown in PMA-contained medium had significantly increased melanin contents regardless of the time (p<0.05). Conclusion : The proliferation of melanocytes was better in physiologic mitogens-contained medium, the melanization was higher in melanocytes of PMA-contained medium.
Humans* ; Melanins ; Melanocytes*

No abstract available.
Hypopigmentation* ; Melanins* ; Melanocytes* ; Melanosis*

Agminated lentigines may be defind as a circumscribed grouping of small pigmented macules arranged in a small or large group, often in a segmental pattern, each macule consisting of a lentiginous epidermal proliferation of melanocytes. We report five cases of agminated lentigines in otherwise healthy persons. Histologic exarnination of the pigmented lesion revealed findings consistent with lentigo simplex.
Humans ; Lentigo* ; Melanocytes

No abstract available.
Eczema ; Inflammation ; Melanocytes ; Nevus

Penile melanosis is a new disease entity which is benign and different from pigmented nevus and acral lentiginous melanoma in situ. A 20-year-old man had hyperpigmented macules on the glans penis and penile shaft for 5 years. Clinical and histologic findings were consistent with penile melanosis and giant melanosome complexes were observed ultrastructurally.
Humans ; Male ; Melanocytes* ; Melanoma ; Melanosis* ; Melanosomes ; Nevus, Pigmented ; Penis ; Young Adult

Melatonin was derived from pineal gland, act as hormone and is known to be extremely active in certain biological systems. To observe the depigmentation effet of melatonin, author induced activation of melanocytes and melanin by UVB irradiation for seven days and then melatonin ointment or ointment base was applied topically on the ear skin of C57 B1 mouse. Tissue samples were obtained from 4 mice in each group before and after UVB irradiation for given days(1,3,5 and 7 week). The morphological, numerical, and ultrastructural changes of epidermal melanocytes were observed with light microscope and electron miroscope after DOPA stain. The results were as follows: 1) In all groups, the number of DOPA positive melanocytes began to decrease from 1 week. 2) The number of DOPA-positive melanocytes in melatonin ointment applied group was significantly lower than in control group. 3) In the electron microscopic findings, the number of melanosomes markedly decreased from 1 week to 7 weeks and a small amount of destructed melanosomes(vacuoles) and destroyed or swollen mitochondria in cytoplasm of th melanocyte appeared more significant in 3% melatonin ointment applied group compared to ointment base applied group from 5 weeks.
Animals ; Cytoplasm ; Dihydroxyphenylalanine ; Ear ; Melanins ; Melanocytes* ; Melanosomes ; Melatonin* ; Mice* ; Mitochondria ; Pineal Gland ; Skin

Melanin is produced in melanocytes and stored in melanosomes. In spite of its beneficial sun-protective effect, abnormal accumulation of melanin results in esthetic problems. Hydroquinone, competing with tyrosine, is a major ingredient in topical pharmacological agents. However, frequent adverse reactions are amongst its major limitation. To solve this problem, several alternatives such as arbutin, kojic acid, aloesin, and 4-n-butyl resorcinol have been developed. Herein, we classify hypopigmenting agents according to their mechanism of action; a) regulation of enzyme, which is subdivided into three categories, i) regulation of transcription and maturation of tyrosinase, ii) inhibition of tyrosinase activity, and iii) post-transcriptional control of tyrosinase; b) inhibition of melanosome transfer, and c) additional mechanisms such as regulation of the melanocyte environment and antioxidant agents.
Arbutin ; Chromones ; Glucosides ; Hydroquinones ; Hypopigmentation ; Melanins ; Melanocytes ; Melanosomes ; Monophenol Monooxygenase ; Pyrones ; Resorcinols ; Tyrosine