TLDR Hair's molecular structure is mostly consistent, but genetic differences affect lipid types, which could help diagnose diseases.
The study analyzed the molecular structure of human scalp hair from 12 individuals using X-ray diffraction, revealing consistent features such as the coiled-coil arrangement of keratin proteins and the presence of lipids in the cell membrane complex. However, significant differences in the plasma membrane composition were attributed to genetics, as evidenced by similarities in genetically related samples like identical twins and a father-daughter pair. The research concluded that common hair care products did not affect the internal keratin structure, and it also addressed and dismissed previous claims linking a specific X-ray signal to breast cancer.
65 citations
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May 2006 in “Journal of Structural Biology” Hair curliness is due to uneven distribution of different cortices within the hair fiber.
66 citations
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June 2004 in “Biophysical Journal” Hard α-keratin in hair has a unique, nonordered structure, different from other fibers.
30 citations
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July 2000 in “PubMed” Hair has unevenly distributed proteins and lipids, with lipids mainly in the cuticle and proteins in the cortex and medulla.
53 citations
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September 1999 in “Journal of Synchrotron Radiation” Keratinous tissues have multiple structural layers, including ordered keratin and lipid granules.
22 citations
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January 2020 in “PeerJ” Keratin peptides in hair might help identify gender and ethnicity.
55 citations
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January 2013 in “International Journal of Cosmetic Science” African hair's keratin structure is influenced by its higher lipid content.
87 citations
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July 2009 in “The journal of investigative dermatology/Journal of investigative dermatology” Human beard hair medulla contains a unique and complex mix of keratins not found in other human tissues.
7 citations
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August 2006 in “Biopolymers” Researchers extracted tiny keratin filaments from human hair by unzipping its outer layer.
71 citations
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August 2005 in “The journal of investigative dermatology. Symposium proceedings/The Journal of investigative dermatology symposium proceedings” Hair keratin-associated proteins are essential for strong hair, with over 80 genes showing specific patterns and variations among people.
1 citations
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August 1981 in “The Journal of Dermatology” All major hair defects involve cuticle abnormalities.