PubMed · 1401844
The leading hairy edge of the lip is claimed to be related to peptic ulcer disease. Implications of this relationship are examined in light of psychiatric and probabilistic possibilities.
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R Byck. 1992. Read my lips.. https://pubmed.ncbi.nlm.nih.gov/1401844/
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On reviewing the data in the literature it is obvious that the differences in the concentrations of certain special elements in human hair for a various number of people are too large to be used as standards or deviations from standards for determining the trace-elemental composition of hair. New questions have arisen with the publication of non-compatible data. What is the distribution of elements on the donor's head area? What is the character of this distribution? Is the distribution function identical for all elements? Hair samples were taken from five points on the heads of six people. The hair samples were analysed using the method of X-ray fluorescence excited by synchrotron radiation (SRXRF), and the results were compared with those from a similar sample analysed using the method of total reflection X-ray fluorescence (TXRF). Elements which show a constant concentration all over the head are identified.
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The mechanism causing the tiger tail phenomenon in trichothiodystrophy (alternating light and dark banding of hair shafts when examined with polarized light) has yet to be explained with certainty. However, we propose a simple and easily tested hypothesis to explain its striking aspect. Although the hair shafts we obtained from patients with trichothiodystrophy were fairly straight, the cortical hair fibers were not. We noticed that these fibers undulate up and down (or back and forth), a feature that is easily observed because of melanin granules embedded in each fiber. The undulations correspond exactly to the banding seen with polarization. Therefore, the tiger tail phenomenon seen in trichothiodystrophy and other hair shaft disorders is caused by a regular undulation of hair fibers within the shafts. Normal hair shafts do not exhibit the phenomenon because the hair fibers are straight and parallel to the long axis of the hair. It is the regular undulation of fibers that changes the optical properties of the hair shafts and causes a predictable banding when the shafts are examined by polarized light.