Preoperative skin preparation: clinical evaluation of depilatory cream.
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Preoperative hair removal by a depilatory cream was compared with routine shaving. Although the incidence of wound infection was similar in both groups, cream depilation was found to be better. It was effective, atraumatic, non-toxic, and could be self-administered. Furthermore, it could be used safely on granulating wounds and did not support bacterial growth. Depilation was associated with a significant reduction in skin surface bacteria and proved to be cheaper than shaving. (+info)
Chemotherapy-induced alopecia in mice. Induction by cyclophosphamide, inhibition by cyclosporine A, and modulation by dexamethasone.
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We introduce cyclophosphamide-induced alopecia (CYP-IA) in C57BL-6 mice as a clinically relevant model for studying the biology of chemotherapy-induced alopecia and for developing anti-alopecia drugs. One injection of CYP to mice with all back skin follicles in anagen VI induces severe alopecia that strikingly reproduces the follicle response, recovery, and histopathology seen in human CYP-IA. CYP dose-dependently induces abnormal follicular melanogenesis and dystrophic anagen or, in more severely damaged follicles, dystrophic catagen. Both dystrophy forms are followed by an extremely shortened telogen phase, but differ in the associated hair loss and in recovery patterns, which determines hair regrowth. This follicular response to CYP can be manipulated pharmacologically: systemic cyclosporine A shifts it toward a mild form of dystrophic anagen, thus retarding CYP-IA and prolonging "primary recovery". Topical dexamethasone, in contrast, forces follicles into dystrophic catagen, which augments CYP-IA, but accelerates the regrowth of normally pigmented hair ("secondary recovery"). (+info)
Accelerated disappearance of melanocytes in bcl-2-deficient mice.
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Follicular melanocytes in bcl-2(-/-) mice have been reported to turn gray during the second hair cycle. Light microscopic analysis revealed that about half of bcl-2(-/-) mouse hair shafts had no detectable melanin granules after the second hair follicle cycle, but the remaining hair appeared to be pigmented normally. After depilation to induce new anagen hair, more than 97% of the hair shafts did not have visible melanin granules in bcl-2(-/-) mice, whereas 100% of the hair shafts in bcl-2(+/+) mice were pigmented. In bcl-2(+/+) mice, dopa-positive melanocytes appeared on day 4 after depilation, whereas bcl-2(-/-) mice developed few dopa-positive melanocytes after depilation, as assessed by light and electron microscopic observation. bcl-2(-/-) mouse hair in the second hair cycle contained about 60-70% less melanin than normal mouse hair, and newly generated bcl-2(-/-) mouse hair after depilation contained a level of melanin as low as that of albino mouse hair. These observations suggest that the expression of bcl-2 might be essential for melanocyte maintenance after the second hair cycle. (+info)