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Pathogenesis of pili annulati.
M Ito1, K Hashimoto, F Sakamoto
1Department of Dermatology, Niigata University School of Medicine, Japan.
Archives of Dermatological Research
|January 1, 1988
Summary
Pili annulati hair shafts exhibit cortical empty spaces due to protein metabolism and ribosome dysfunction. This leads to abnormal keratin formation and the characteristic shiny appearance of affected hair.
Area of Science:
- Dermatology
- Cell Biology
- Biochemistry
Background:
- Pili annulati is a rare hair shaft disorder.
- The characteristic appearance of pili annulati hairs is due to structural abnormalities.
Purpose of the Study:
- To investigate the pathogenesis of pili annulati.
- To elucidate the cellular and molecular basis of the hair shaft abnormalities in pili annulati.
Main Methods:
- Stereoscopic and light microscopy of plucked scalp hairs and hair roots.
- Transmission electron microscopy (TEM) of differentiating cortical cells.
- Histochemical analysis of keratinized hair cortex.
Main Results:
- Cortical empty spaces were identified as the cause of the shiny appearance.
- TEM revealed cytoplasmic vacuoles, dense bodies, uneven ribosome distribution, and abnormal spaces in differentiating cortical cells.
- Abnormal hair segments showed irregular empty spaces in the cortex and increased residual SH groups.
Conclusions:
- Pili annulati may stem from a protein metabolism disorder.
- Partial dysfunction of cytoplasmic ribosomes appears to impair cortical keratin formation.
- These molecular defects lead to the structural abnormalities observed in pili annulati.