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Hair Fibre (hair + fibre)

Distribution by Scientific Domains

Medical Sciences	87%

Selected Abstracts

6-O glucose linoleate supports in vitro human hair growth and lipid synthesis

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2007
P. Vingler
Synopsis The hair follicle is a very active organ with a complex structure, which produces a hair fibre at a rate of 0.3 mm a day. Accordingly, the hair follicle is highly demanding in energy source, as the hair bulb matrix cells are endowed with one of the highest rates of proliferation in the human body. Moreover, recent data have shown the involvement of lipids in hair follicle function. As in vitro -grown hair follicle keeps producing a hair fibre that closely resembles the natural hair fibre, we decided to use this model to investigate the role of a new of glucose linoleate derivative (6-O-linoleyl- d -glucose: 6-O-GL) as a lipid precursor and energy provider. Our results demonstrated that 6-O-GL was (i) quite stable and surprisingly resistant to oxidative degradation, and (ii) readily taken up and metabolized by the hair follicle into various lipids, namely neutral lipids, ceramides and polar lipids. Moreover, it supported hair follicle growth and survival in a glucose- and linoleic-acid free medium. 6-O-GL thus appeared to be a bi-functional nutrient, ensuring both proper fibre quality and production by the hair follicle. Résumé Le follicule pileux est un organe très actif et d'une structure très complexe, qui produit la tige pilaire au rythme de 0.3 mm par jour. En conséquence, le follicule pileux est très demandeur en ressources énergétiques, les cellules de la matrice bulbaire ayant un des taux de prolifération les plus élevé de l'organisme. De plus des études récentes ont mis en évidence le rôle de lipides dans le fonctionnement du follicule pileux. Puisque le follicule pileux in vitro continue à produire une fibre de qualité identique à celle d'une fibre naturelle, nous avons décidé d'utiliser ce modèle pour étudier le rôle d'un nouveau linoléate de glucose (6-O-linoleyl- d -glucose: 6-O-GL) en tant que précurseur lipidique et source d'énergie. Nos résultats démontrent que le 6-O-GL est très stable et étonnamment résistant à l'auto oxydation, qu'il est capté et métabolisé par le follicule pileux en divers lipides, neutres, polaires et céramides. De plus, le 6-O-GL soutient la croissance et la survie du follicule dans un milieu dépourvu de glucose et d'acide linoléique. Le 6-O-GL apparaît donc comme un agent bi-fonctionnel, permettant au follicule pileux de maintenir in vitro la production de la tige pilaire. [source]

Comparative aspects of the inner root sheath in adult and developing hairs of mammals in relation to the evolution of hairs

JOURNAL OF ANATOMY, Issue 3 2004
Lorenzo AlibardiArticle first published online: 17 SEP 200
Abstract The inner root sheath (IRS) allows the exit of hairs through the epidermal surface. The fine structure of monotreme and marsupial IRS and trichohyalin is not known. Using electron microscopy and immunocytochemistry, the localization of trichohyalin and transglutaminase have been studied in monotreme and marsupial hairs, and compared with trichohyalin localization in placental hairs. Trichohyalin in all mammalian species studied here is recognized by a polyclonal antibody against sheep trichohyalin. This generalized immunoreactivity suggests that common epitopes are present in trichohyalin across mammals. In differentiating IRS cells, trichohyalin granules of variable dimensions are composed of an immunolabelled amorphous matrix associated with a network of 10,12-nm-thick keratin filaments. Transglutaminase labelling is present among keratin bundles and trichohyalin granules, and in condensed nuclei of terminally differentiating cells of the inner root sheath. The IRS in monotreme hairs is multistratified but lacks a distinguishable Henle layer. Cornification of IRS determines the sculpturing of the fibre cuticle and later shedding from the follicle for the exit of the hair fibre on the epidermal surface. It is hypothesized that the stratification of IRS in Henle, Huxley and IRS cuticle layers is derived from a simpler organization, like that present in the IRS of monotremes. The IRS is regarded as a localized shedding/sloughing layer needed for the exit of hairs without injury to the epidermis. The formation of the IRS during the evolution of mammalian epidermis allowed the physiological exit of hairs produced inside the skin. The peculiar morphogenesis of hairs in possible primitive skins, such as those of the monotremes (mammals with some reptilian characteristics) or the tails of some rodents (a scaled skin), may elucidate the evolution of hairs. In monotreme and rodent tail skin, the dermal papilla remains localized on the proximal side of the hair peg and forms a hair placode with bilateral symmetry. The papilla is progressively surrounded by the down-growing hair peg until a dermal papilla with radial symmetry is formed. It is speculated that the progressive reduction of the extended dermal papilla of reptilian scales into small and deep papillae of therapsid reptiles produced hairs in mammals. [source]

Hair interior defect in AKR/J mice

CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 4 2009
K. A. Giehl
Summary Background., All AKR/J mice have a subtle defect that involves malformation of the central portion of hair fibres that is best visualized under white and polarized light microscopy. Aims., This study sought to characterize the clinical and ultrastructural features of the hair interior defect (HID) phenotype and to determine the chromosomal localization of the hid mutant gene locus. Methods., White and polarized light microscopy combined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the HID phenotype. Complementation testing and gene-linkage studies were performed to map the locus. Results., Using SEM, the hair-fibre structure on the surface was found to be similar to hairs obtained from normal BALB/cByJ+/+and C57BL/6 J+/+mice. There were also no differences in sulphur content. TEM revealed degenerative changes in the medulla similar to that seen by light microscopy. This autosomal recessive mutation is called HID (locus symbol: hid). We mapped the hid locus to the distal end of mouse chromosome 1. No genes reported to cause skin or hair abnormalities are known to be within this interval except for the lamin B receptor (Lbr), which had been excluded previously as the cause of the hid phenotype in AKR/J mice. Conclusion., A potentially novel gene or known gene with a novel phenotype resides within this interval, which may shed light on human diseases with defects in the inner structure of the hair fibre. [source]

Investigation of dyed human hair fibres using apertureless near-field scanning optical microscopy

JOURNAL OF MICROSCOPY, Issue 2 2006
F. FORMANEK
Summary We present the first studies of dyed human hair fibres performed with an apertureless scanning near-field optical microscope. Samples consisted of 5-µm-thick cross-sections, the hair fibres being bleached and then dyed before being cut. Hair dyed with two molecular probes diffusing deep inside the fibre or mainly spreading at its periphery were investigated at a wavelength of 655 nm. An optical resolution of about 50 nm was achieved, well below the diffraction limit; the images exhibited different optical contrasts in the cuticle region, depending on the nature of the dye. Our results suggest that the dye that remains confined at the hair periphery is mainly located at its surface and in the endocuticle. [source]