Electron microscopy and tomography reveal that sodium 2-naphthalene sulfonate incorporated into perming solutions swells and tilts trichocyte intermediate filaments causing straightening of curly Japanese human hair.

OBJECTIVE: A new hair-care process has been specifically developed for the straightening of curved Japanese woman's hair . The process included sodium 2-naphthalene sulfonate (SNS) in the reduction and oxidation steps of a conventional perming process. Our objective was to develop an understanding of how this process caused hair straightening by measuring the changes to morphology and ultrastructure between untreated, conventionally permed and SNS permed hair. Untreated and SNS permed Merino wool fibres were used to confirm structural changes. METHODS: Japanese hair samples were measured for single-fibre curvature before and after perming treatments. A silver staining method was developed to stain hair fibres without changing fibre curvature so that transmission electron microscopy could be used to measure changes in the lateral dimensions of all structural components from the cellular to protein filament level. Electron tomography determined intermediate filament slopes and slope changes after SNS perming relative to the central longitudinal axis of the fibre. RESULTS: SNS perming was found to cause greater lateral swelling than conventional perming of: the paracortical cells of wool; the cuticle, the cuticular cell membrane complex and the macrofibrillar centre-to-centre distance of hair; and of the intermediate filaments in wool and hair. In curved hair, SNS perming caused the intermediate filaments of the helical macrofibrils to simultaneously swell and to tilt further, resulting in the slight longitudinal contraction of the macrofibrils. The overall swelling and tilting was greatest in the helical macrofibrils of Type B cortical cells predominately located in the convex fibre half. The presence of a higher percentage of helical macrofibrils in the convex fibre half than in the concave fibre half caused a contraction differential between the two halves leading to straighten of the curved fibre. A mechanical model was proposed to explain how SNS perming straightened curly hair. CONCLUSION: The effects of conventional and SNS perming on the morphological and ultrastructural components of curved Japanese hair and high-curl Merino wool fibres have given clear insights into understanding the mechanism of fibre curvature change.

OBJECTIF: Un nouveau procédé de soin des cheveux a été spécialement conçu pour lisser les cheveux ondulés des Japonaises[1]. Le procédé utilise le sulfonate de naphthalène-2 sodium (SNS) dans les étapes de réduction et d'oxydation du procédé conventionnel de permanente. Notre objectif était de comprendre la façon dont ce procédé induisait le lissage des cheveux en mesurant les différences de changement morphologique et ultrastructural entre les cheveux non traités et ceux soumis à une permanente conventionnelle et une permanente à base de SNS. Des fibres de laine de mérinos non traitées et soumises à une permanente à base de SNS ont été utilisées pour confirmer les changements structurels. MÉTHODES: Des échantillons de cheveux japonais ont été utilisés pour mesurer la courbure d'une fibre isolée avant et après le traitement de permanente. Une méthode de coloration argent a été mise au point pour colorer les fibres de cheveux sans changer la courbure des fibres afin de pouvoir utiliser la microscopie électronique en transmission pour mesurer les modifications des dimensions en largeur de tous les composants structurels du filament, de la cellule aux protéines. Une tomographie électronique a déterminé les pentes intermédiaires et les changements de pente des filaments après permanente à base de SNS par rapport à l'axe longitudinal central de la fibre. RÉSULTATS: On a constaté que la permanente à base de SNS induisait un gonflement en largeur plus important que la permanente classique des cellules paracorticales de la laine; de la cuticule, du complexe de la membrane cellulaire cuticulaire et de la distance centre à centre des macrofibrilles du cheveu; et des filaments intermédiaires dans la laine et les cheveux. Dans les cheveux ondulés, la permanente à base de SNS a provoqué à la fois un gonflement et une inclinaison des filaments intermédiaires des macrofibrilles hélicoïdales, entraînant une légère contraction longitudinale des macrofibrilles. Au total, le gonflement et l'inclinaison étaient plus importants dans les macrofibrilles hélicoïdales des cellules corticales de type B situées principalement dans la moitié convexe de la fibre. La présence d'un pourcentage plus élevé de macrofibrilles hélicoïdales dans la moitié convexe par rapport à la moitié concave de la fibre a entraîné une contraction différentielle entre les deux moitiés qui a entraîné le redressement de la fibre courbée. Un modèle mécanique a été proposé pour expliquer comment la permanente à base de SNS lissait les cheveux bouclés. CONCLUSION: Les effets de la permanente conventionnelle et à base de SNS sur les composants morphologiques et ultrastructuraux des cheveux japonais ondulés et des fibres de laine très frisés de mérinos ont permis de mieux comprendre le mécanisme du changement de courbure des fibres.

Redox proteomic evaluation of oxidative modification and recovery in a 3D reconstituted human skin tissue model exposed to UVB.

OBJECTIVE: Exposure to UV in humans resulting in sunburn triggers a complex series of events that are a mix of immediate and delayed damage mediation and healing. While studies on the effects of UV exposure on DNA damage and repair have been reported, changes in the oxidative modification of skin proteins are poorly understood at the molecular level, despite the important role played by structural proteins in skin tissue, and the effect of the integrity of these proteins on skin appearance and health. Proteomic molecular mapping of oxidation was here applied to try to enhance understanding of skin damage and recovery from oxidative damage and UVB exposure. METHODS: A redox proteomic-based approach was applied to evaluating skin protein modification when exposed to varying doses of UVB after initial oxidative stress, via tracking changes in protein oxidation during the healing process in vitro using a full-thickness reconstituted human skin tissue model. Bioassays and structural evaluation confirmed that our cultured skin tissues underwent a normal physiological response to UVB exposure. RESULTS: A set of potential skin marker peptides was generated, for use in tracking skin protein oxidative modification. Exposure to UVB after thermal oxidative stress was found to result in higher levels of skin protein oxidation than a non-irradiated control for up to seven days after exposure. Recovery of the skin proteins from oxidative stress, as assessed by the overall protein oxidation levels, was found to be impaired by UVB exposure. Oxidative modification was largely observed in skin structural proteins. CONCLUSION: Exposure of skin proteins to UVB exacerbates oxidative damage to structural skin proteins, with higher exposure levels leading to increasingly impaired recovery from this damage. This has potential implications for the functional performance of the proteins and inter-related skin health and cosmetic appearance.

Transmission electron microscopy staining methods for the cortex of human hair: a modified osmium method and comparison with other stains.

For wool, superior staining of a wide range of ultrastructural components is achieved by en bloc treatment of fibres with a chemical reductant followed by osmium tetroxide. For human scalp hair, although staining quality is similar, the penetration of reagents is poor, resulting in large parts of the fibre cortex remaining unstained. Here we describe a modification to the reduction-osmication method in which reagents penetrate through a cut fibre end, allowing visualization of a wide range of features across the cortex. We compare the staining quality, artefacts and range of structure rendered visible using transmission electron microscopy for en bloc reduction-osmication to other staining alternatives including en bloc silver nitrate and section stains based on uranyl acetate and lead citrate, phosphotungstic acid, potassium permanganate, ammoniacal silver nitrate and some combinations of these stains. The effects of hair-care treatments are briefly examined.

Morphology and ultrastructure of antler velvet hair and body hair from red deer (Cervus elaphus).

We provide a detailed description of the ultrastructure of deer hair fibers. Guard hairs and underhairs from the winter coat of red deer (Cervus elaphus), and antler velvet hairs from the same species were examined. All fibers displayed the typical keratin fiber morphology of overlapping cuticle cells surrounding a core of cortex cells, and often a centrally-located medulla, but there were considerable differences in the diameter, cuticle thickness, and scale pattern, and in the relative amounts of cortex and medulla along individual fibers, and between the different types of fiber. In addition, closer examination of cortex cells using transmission electron microscopy revealed considerable differences in the arrangement of intermediate filaments in the different fiber types. Fine underhairs appeared similar to fine wool fibers from sheep because intermediate filament arrangements were very similar to those found in wool orthocortex cells and paracortex cells. In addition, a similar bilateral distribution of these cell types was evident. However, in the antler velvet hairs and the guard hairs, intermediate filament arrangements were more variable and complex, and showed similarities to those in heterotype cortex cells described for human hair.

Overuse ankle injuries in professional Irish dancers.

BACKGROUND: Overuse ankle injuries have been described in elite athletes and professional ballet dancers however the spectrum of injuries experienced by professional Irish dancers has not been defined. METHODS: A troupe of actively performing dancers from an Irish-dance show were recruited (eight male, ten female; mean age, 26 years). The prevalence of overuse injuries in the right ankle was determined from magnetic resonance imaging. Foot and ankle self-report questionnaires were also completed (AOFAS and FAOS). RESULTS: Only three ankles were considered radiologically normal. Achilles tendinopathy, usually insertional, was the most frequent observation (n=14) followed by plantar fasciitis (n=7), bone oedema (n=2) and calcaneocuboid joint degeneration (n=2). There were limited correlations between MRI patterns and clinical scores indicating that many conditions are sub-clinical. Dancers with ankle pain had poor low (p=0.004) and high (p=0.013) level function. CONCLUSIONS: Overuse ankle injuries are common in Irish dancers. Incorporating eccentric exercises and plantar fascia stretching into a regular training program may benefit this population.

Surgical site infection with methicillin-resistant Staphylococcus aureus after primary total hip replacement.

We have analysed the management and clinical outcome of a series of consecutive patients who had a total hip replacement and developed post-operative surgical site infection (SSI) with methicillin-resistant Staphylococcus aureus. The incidence of this infection was 1% over a period of five years. We studied SSI in 15 patients (16 infections) with a mean age of 72.7 years (53 to 81). In all, 12 of the infections occurred early and half of the infections involved the prosthesis, resulting in an increase of 11-fold in the cumulative hospital stay. Methicillin-resistant Staph. aureus was successfully eradicated in all the patients after a mean follow-up of 53.6 months (25 to 88). Superficial incisional infections resolved after antibiotic therapy alone while deep infections required multiple operative debridements. Attempted retention of the implant in early organ space infections was successful in only one of five patients. Only three patients with implant-level infections obtained a pain-free, functional prosthesis while a further three required excision arthroplasty. We have formulated a protocol of treatment which may serve as a guide in the management of these infections.