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Increased size of stage II and III melanosomes during PUVA therapy
Abstract:
Four different theories have been presented to show how early melanosomes are formed and at what stage in melanosome formation melanization starts. In the present investigation the perikaryon of melanocytes have been studied and the longitudinal and the transverse diameter of stage I-IV melanosomes estimated before and after PUVA therapy in 5 patients. An increase in the longitudinal diameter of stage II and III melanosomes was found, whereas no increase in stage I and IV melanosomes was detected. No increase in vesiculo-globular bodies was detected in stage I and II melanosomes after PUVA therapy, while in stage III melanosomes vesiculo-globular bodies appeared to have increased in number of PUVA therapy. It is concluded that during stimulated melanogenesis--as seen after PUVA therapy--an unknown mechanism is activated, causing increased amounts of structural proteins to be incorporated into each stage II melanosome. The vesiculo-globular bodies do not appear to take part in this process.
Insights
PUVA therapy stimulates melanogenesis by activating an unknown mechanism that increases structural protein incorporation into stage II melanosomes. Vesiculo-globular bodies do not appear to be involved in this process.
Area of Science:
- Cell Biology
- Dermatology
- Biochemistry
Background:
- Melanosome formation and melanization stages are not fully understood.
- PUVA therapy is known to stimulate melanogenesis.
Purpose of the Study:
- To investigate the effects of PUVA therapy on melanosome formation and melanization.
- To determine the stage at which melanization begins during melanosome development.
Main Methods:
- Studied melanocyte perikaryons in 5 patients before and after PUVA therapy.
- Measured longitudinal and transverse diameters of stage I-IV melanosomes.
- Assessed the number of vesiculo-globular bodies in melanosomes.
Main Results:
- Increased longitudinal diameter observed in stage II and III melanosomes post-PUVA therapy.
- No significant changes in diameter for stage I and IV melanosomes.
- Increased vesiculo-globular bodies noted in stage III melanosomes after PUVA therapy.
Conclusions:
- Stimulated melanogenesis via PUVA therapy involves an unknown mechanism enhancing structural protein incorporation into stage II melanosomes.
- Vesiculo-globular bodies do not seem to play a role in this stimulated melanogenesis process.