Rushton D H, Norris M J, James K C
School of Pharmacy and Biomedical Sciences, Portsmouth Polytechnic, Cardiff, UK.
Clin Exp Dermatol. 1990 Jan;15(1):24-8. doi: 10.1111/j.1365-2230.1990.tb02013.x.
Trichorrhexis nodosa is a common shaft defect affecting scalp hair. Two-hundred scalp hairs exhibiting trichorrhexis nodosa were obtained from two normal females; samples were prepared from proximal shaft, pre-nodule, nodule and post-nodule sections and analysed for their respective amino-acid compositions. Significant reductions in cystine (P less than 0.001) of the pre-nodule, nodule and post-nodule sections, which decreased by 17.2%, 19.8% and 14.3%, respectively, and an increase in the acidic amino acids (P less than 0.03) were found, compared to values obtained from proximal shaft of the same hairs. The majority of nodules occurred within the last 10% of the shaft, and the similarity in amino-acid compositions between pre-nodule, nodule and post-nodule sections suggests that 'weathering' is the major factor influencing nodule occurrence. It is postulated that nodule formation requires a specific degree of exposure to 'weathering' together with a reduction in cuticle cell coverage. It is suggested that an initial structural defect, created by a change in the DNA coding for a cuticle polypeptide fraction, could be responsible for the selective and isolated presentation of the nodule within a 'weathered' section of hair shaft.
结节性脆发病是一种影响头皮毛发的常见发干缺陷。从两名正常女性身上获取了200根表现出结节性脆发病的头皮毛发；从毛发近端、结节前、结节和结节后部分制备样本，并分析其各自的氨基酸组成。与同一毛发近端部分的值相比，结节前、结节和结节后部分的胱氨酸显著减少（P小于0.001），分别减少了17.2%、19.8%和14.3%，并且酸性氨基酸增加（P小于0.03）。大多数结节出现在发干的最后10%范围内，结节前、结节和结节后部分氨基酸组成的相似性表明“风化”是影响结节发生的主要因素。据推测，结节形成需要一定程度的“风化”暴露以及角质形成细胞覆盖减少。有人提出，由角质形成多肽部分的DNA编码变化产生的初始结构缺陷，可能是毛发干“风化”部分内结节选择性和孤立出现的原因。
