202 JOURNAL OF COSMETIC SCIENCE Figure 7. A split end treated for 30 minutes with fluorescein-labeled peptides. Block top method. The hair has split into many separated fragments. Intense staining of the cortical nuclear remnants is still visible but not as sharp as in less damaged hairs. The continuous low level of fluorescence indicates that the peptides have permeated throughout the entire specimen. pervaded all parts, but it was noticeable that the nuclear remnants were not as sharply defined as had been seen in untreated hairs and of much lower intensity. The most likely reason for this is that effete basic nuclear proteins, normally found in untreated hairs, had been extracted during the multifarious processes of weathering. IMPLICATIONS FOR TOILETRY TREATMENTS OF HAIR Since water normally plasticizes and softens hair, the results of Gamez-Garcia (1) and Chahal et al. (2) provide expectations for significant changes in the textural behavior of human hair following treatment with hydrolyzed wheat proteins. The relatively un- crosslinked proteins of the hair's intermacrofibrillar matrix are major sites for binding water (9) and can be regarded as the main plasticizing elements separating the stiffer macrofibrils in undamaged root-end hair. Exposure of hair to excessive sunlight dra- matically increases its susceptibility to splitting (10), likely through the formation of new crosslinks in the intermacrofibrillar matrix but also through a loss of water-binding capacity. The absorption of hydrolyzed wheat proteins will increase the plasticity of hair in general by dint of their ability to retain moisture for long periods. We predict that their specific incorporation into the very components that are damaged by sunlight exposure will render the hair less susceptible to the formation of split ends. ACKNOWLEDGMENTS Particular thanks are due to Dr. Vyvyan Howard of the Department of Infant and Fetal Toxico-Pathology of Liverpool University for providing access to his confocal microscope and to Mr. Liam Barlow of the same department for technical assistance with the work.
HAIR AND HYDROLYZED WHEAT PROTEINS 203 REFERENCES (1) M. Gamez-Garcia, Effects of some oils, emulsions, and other aqueous systems on the mechanical properties of hair at small deformations, J. Soc. Cosmet. Chem., 44, 69-87 (1993). (2) S. P. Chahal, N. I. Challoner, and R. T. Jones, Moisture regulation of hair by cosmetic proteins as demonstrated by dynamic vapour sorption: A novel efficacy testing technique, Proc. 14th Latin- American and Iberian Cong. Cosmet. Chem., Santiago Chile, 45-56 (1999). (3) R. T. Jones and S. P. Chahal, The use of radiolabelling techniques to measure substantivity to, and penetration into hair of protein hydrolysates, Internat. J. Cosmet. Sci., 19, 215-226 (1997). (4) T. Wilson, Ed., Con•bcal Microscopy (Academic Press, San Diego, 1990). (5) J. A. Swift, "The Detection of Pores and Holes in Hair by Electron Microscopy," in Hair Research fir the Next Millennium, D. J.J. Van Neste and V. A. Randall, Eds. (Elsevier Science BV, Amsterdam, 1996), pp. 109-112. (6) J. A. Swift and B. Bews, The chemistry of human hair cuticle. Part 3. The isolation and amino acid analysis of various subfractions of the cuticle obtained by pronase and trypsin digestion,J. Soc. Cosmet. Chem., 27, 289-300 (1976). (7) J. A. Swift, "The Histology of Keratin Fibers," in The Chemistry of Natural Protein Fibres, R. S. Asquith, Ed. (Plenum Press, New York, 1977), pp. 81-146. (8) P. Kassenbeck, Das haar und seine struktur, Wella AG, Darmstadt, Germany (1984). (9) J. A. Swift and A. K. Allen, "Swelling of Human Hair by Water," in Abstracts of Sth Internat. Hair Sci. Symp., Kiel, Germany (Deutsches Wollforshungsinstitut, Aachen, Germany, 1992). (10) M.A. Pykett and J. A. Swift, Schutz von Haarbruch nachweisen: Ein neues Testverfahren fiir eine bessere Datenbasis, Parr. u. Kosmetik, 79, 38-40 (1998).
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