Pigment change and melanocyte distribution in guinea pig skin after cutaneous freeze injury.

Cryosurgery has been recommended for the treatment of cutaneous neoplasms, including benign and malignant melanocytic tumors. The main side effect of this treatment is pigment disruption which may be prolonged. There are no quantitative studies on melanocyte distribution after freeze injury. In this study the effect of standardized freeze times on melanocytes in guinea pig skin (tricolored) is described at the anatomic level and at the light and electron microscopic level. Melanocytes are quantified in epidermal sheets following dopa staining at 1-, 2-, and 3-month intervals after freezing. All the lesions were initially hypopigmented with a peripheral rim of hyperpigmentation. This was a transient phenomenon associated with an absence of melanocytes. Pigment migrated into the lesions so that after 3 months all the lesions on black skin were diffusely hyperpigmented. Pigment was slower to return to the red skin. Hair follicles were destroyed in the center of the lesion. The epidermal sheets demonstrated that the hyperpigmentation was an epidermal phenomenon and was associated with increased numbers of melanocytes (p less than 0.001). These melanocytes were distributed evenly throughout the lesion in contrast to the irregular distribution in normal skin.

Linkage of monilethrix to the trichocyte and epithelial keratin gene cluster on 12q11-q13.

Monilethrix is characterized by beaded or moniliform hair, which results from the periodic thinning of the hair shaft. The beaded hair thus produced is subject to excess weathering and premature fracturing at the internodes. Clinically, monilethrix presents with short, fragile, broken hair. The follicular abnormalities range from subtle perifollicular abnormalities range from subtle perifollicular erythema and hyperkeratosis to horny follicular papule formation. At the ultrastructural level, cytolysis and keratin tonofilament clumping (epidermolysis) are seen in the cortical cells of the bulb of the hair follicle. Microsatellite markers flanking the keratin gene clusters at 17q12-q21 and 12q11-q13 were used to perform linkage analysis in a monilethrix pedigree. This study demonstrates linkage of monilethrix in a pedigree to microsatellite DNA loci mapping to the region on chromosome 12 containing the type II keratin cluster. A major group of structural hair proteins, the basic type II trichocyte keratins, map within this epithelial cytokeratin gene cluster. This study implicates a mutation in a trichocyte keratin gene in the pathogenesis of a structural hair disorder.

Spironolactone is an effective and well tolerated systemic antiandrogen therapy for Hirsute women.

We treated 22 hirsute women with spironolactone in an open trial to determine whether it caused objective changes in hair growth. Among them, 18 women completed 12 months therapy with 200 mg spironolactone daily. During this period, the mean daily linear growth rates of hair on the face, abdomen, and thigh were reduced to 66% (P less than 0.001), 75% (P less than 0.01), and 72% (P less than 0.001) of their pretreatment values. The mean hair shaft diameters were reduced to 83% (P less than 0.01) on the face, 88% (P less than 0.001) on the arm, 74% (P less than 0.01) on the abdomen, and 80% (P less than 0.001) on the thigh. Daily hair volume production was calculated from the diameter and daily growth rate; it was reduced to 60% (P less than 0.01) on the face, 52% (P less than 0.01) on the arm, 34% (P less than 0.001) on the abdomen, and 48% (P less than 0.001) on the thigh. Six of the 18 women who completed the study developed midcycle vaginal bleeding, and 3 women had previously irregular menstrual cycles regulated. We conclude that spironolactone is effective and well tolerated for hirsute women.

Acquired progressive kinking of hair. Report of six cases and review of literature.

Acquired progressive kinking of hair is an entity distinct from woolly hair in its onset at or after puberty, predominant involvement of frontal, temporal, and vertex regions of the scalp as well as the supra-auricular and postauricular margins, and a tendency for affected hairs to resemble pubic hair both in texture and color. We consider the condition to be androgen dependent and likely to progress to male pattern baldness. The condition "whisker hair" is probably a variant of acquired progressive kinking of hair.

The embryology and development of human scalp hair.

In summary, without a basic knowledge of embryology and development of human hair many abnormalities that occur in early postnatal life cannot be classified. Classification of abnormalities is necessary if specific genetic or biochemical causes are to be looked for and prognosis and genetic counseling accurately assessed.

Dermatologic diseases of the nail unit other than psoriasis and lichen planus.

Diseases in which involvement of the nails may be helpful in the diagnosis of dermatologic disease elsewhere include psoriasis, lichen planus, Darier's disease, alopecia areata and totalis, keratotic scabies, scleroderma, and lupus erythematosus and dermatomyositis. Dermatologic diseases in which involvement of the nail commonly occurs but is relatively nonspecific and not diagnostic include dermatitis, lichen striatus, parakeratosis pustulosa, pityriasis rubra pilaris, acrokeratosis paraneoplastica, pemphigus vulgaris, epidermolysis bullosa, porokeratosis of Mibelli, and acanthosis nigricans. These entities are described and treatments summarized as appropriate.

Trauma to the nail unit including occupational sports injuries.

Trauma to the nail unit is one of the most common causes of onychodystrophy and may be acute (a single overwhelming injury) or chronic (repeated minor injury). Immediate effects of acute trauma include splinter hemorrhages, subungual hematomas, and nail shedding. Delayed deformities include splits and ridges, pterygium, hook nails, pigment bands, and ectopic nail. Also discussed are the results of chronic trauma, including self-inflicted injury and repeated indirect injury.

The response of keloid scars to cryosurgery.

The effectiveness of cryosurgery in the treatment of a series of keloid scars in 17 patients has been investigated. A portable liquid nitrogen spray was used, and cryosurgical schedules shown experimentally to produce minimal scarring in normal skin were utilized in order to minimize recurrence rate. Temperatures achieved were monitored using digital thermometers, and scar volumes before and 1 month after treatment were calculated from plaster impressions. Response to treatment was poor, only two scars exhibiting marked reduction in volume without further, more severe freezing. Calculations of an accurate recurrence rate were impossible because of this poor response, but both earlobe keloids responded well and showed no evidence of recurrence at 1 year. Results provide further evidence that lesions made up principally of fibrous tissue respond poorly to cryosurgery.

Minoxidil-induced changes in the contraction of collagen lattices by human skin fibroblasts.

This investigation has studied the effect of minoxidil on the contraction of hydrated collagen lattices by human dermal fibroblasts. Type I collagen was mixed with a fibroblast suspension and polymerized, and minoxidil 10 to 800 micrograms/ml (0.05 to 4 mM) was added at the time the lattices were released. Minoxidil at concentrations from 100 to 600 micrograms/ml inhibited contraction in a dose-dependent manner, whereas 800 micrograms/ml prevented contraction completely, most cells remaining rounded. Considerable inhibition was already evident within 24 hours. Visualization of living cells with MTT and cell counts showed that inhibition in the first 48 hours was not due to fibroblast death. Exchange of minoxidil to normal medium led to a resumption of contraction and a return to an elongate morphology. Minoxidil at 10 micrograms/ml had no significant effect on lattice contraction, whereas at 100 micrograms/ml it slowed contraction without affecting proliferation or morphology, as observed under the light microscope. The inhibitory effect of minoxidil should be investigated further in relation to the control of contraction of wounds in vivo.