Evaluation of a silicone occlusive dressing after laser skin resurfacing.

BACKGROUND: Closed dressings are thought to promote postoperative wound healing after laser skin resurfacing; however, quantitative data are lacking. OBJECTIVE: To compare postoperative healing after combination carbon dioxide and erbium:YAG full-face laser skin resurfacing in patients who were treated with a silicone occlusive dressing (Silon-TSR; Bio Med Sciences, Inc, Bethlehem, Pa) vs open-wound care consisting of soaks and ointment application. DESIGN: Thirty-five patients with closed dressings compared retrospectively with 35 control subjects with open-wound care. In a prospective evaluation, 27 patients with closed dressings were then compared with 27 historical controls matched by age, sex, skin type, and treatment technique. Erythema, crusting, swelling, pain, pruritus, purpura, long-term complications, and dressing comfort were evaluated. SETTING: Referral-based academic practice. RESULTS: Prospectively, closed-dressing and open-wound care groups differed significantly in maximum erythema severity (1.8 vs 2.0 on a scale of 0-3; P =.03), noticeable erythema duration (15.4 vs 31.1 days; P =.04), and time until complete erythema resolution (41.8 vs 96.1 days; P =.02). Swelling resolution was more rapid in the dressing group (12.1 vs 29.5 days; P =.02). Crusting was limited to uncovered areas in the dressing group, and crusting duration was shorter (5.0 vs 9.1 days; P<.001). Pain was more likely to be reported prospectively, but severity was mild, in the closed-dressing group. Other short- and long-term complications did not differ significantly. Subjective patient attitudes toward the dressing were positive. CONCLUSIONS: Occlusive silicone dressing application decreases immediate postoperative morbidity with significantly reduced severity and duration of erythema and decreased duration of swelling and crusting. Long-term results and complication rates remain unchanged.

Transverse leukonychia with systemic infection.

Transverse white nail bands (leukonychia) have been described in association with systemic illnesses and exposure to toxins, and medications. We describe the occurrence of transverse nail bands in two patients following acute systemic illnesses. In the first case, transverse white nail bands developed in a 30-year-old human immunodeficiency virus-positive man following acute pulmonary tuberculosis. In the second case, transverse white nail bands were noted in an 80-year-old patient following Streptococcus intermedius empyema.

Optical hair removal.

Traditional methods of hair removal have proven unsatisfactory for many individuals with excessive or unwanted hair. In the last few years, several lasers and xenon flashlamps have been developed that promise to fulfill the need for a practical, safe, and long-lasting method of hair removal. Aggressive marketing of these has contributed to their popularity among patients and physicians. However, significant controversy and confusion surrounds this field. This article provides a detailed explanation of the scientific underpinnings for optical hair removal and explores the advantages and disadvantages of the various devices currently available (Nd:YAG, ruby, alexandrite, diode lasers, and xenon flashlamp). Treatment and safety guidelines are provided to assist the practitioner in the use of these devices. Although the field of optical hair removal is still in its infancy, initial reports of long-term efficacy are encouraging.

Constitutive expression of B7-1 (CD80) on mouse keratinocytes does not prevent development of chemically induced skin papillomas and carcinomas.

Expression of the B7-1 (CD80) costimulatory molecule in a variety of tumor cell lines leads to an enhanced CD8+ T cell response to tumor Ags. We used transgenic mice constitutively expressing B7-1 on keratinocytes (K14/B7-1 line) to determine whether keratinocyte B7-1 expression would inhibit the development of papillomas and carcinomas following two-stage chemical carcinogenesis in skin. FVB inbred mice carrying the K14/B7-1 transgene and controls were initiated with 25 micrograms of 7,12-dimethylbenz[a]anthracene and promoted weekly with 5 micrograms of 12-O-tetradecanoylphorbol-13-acetate for 20 wk. Expression of the B7-1 transgene did not result in statistically significant decreases in the mean number of papillomas or carcinomas compared with controls. The incidence of carcinomas in both transgenic and control mice reached 90% or greater by 60 wk after initiation. Carcinoma cell lines established from the K14/B7-1 mice maintained expression of B7-1 and Kq. These B7-1 expressing carcinomas grew progressively following intradermal injection into syngeneic FVB mice, further demonstrating their inability to evoke protective tumor immunity. These same carcinoma cell lines were rapidly rejected by minor alloantigen-mismatched SWR mice, confirming their susceptibility to immune effector mechanisms. The failure of constitutive B7-1 expression on keratinocytes to prevent the growth of squamous cell papillomas and carcinomas may reflect the limited immunogenicity of tumors arising after initiation-promotion carcinogenesis. Our results in this transgenic model system are further evidence that B7-1 gene therapy alone may not be sufficient to induce protective immunity to some types of tumors.

Keratinocyte expression of B7-1 in transgenic mice amplifies the primary immune response to cutaneous antigens.

Resting epidermal keratinocytes do not express B7-1 and other known CD28 counterligands with costimulatory activity. The absence of these costimulators on keratinocytes correlates with their ability to preferentially induce T-cell anergy instead of T-cell activation. To test the hypothesis that keratinocytes expressing a CD28 counterligand would be more effective inducers of T-cell-mediated immune responses in skin, we prepared transgenic mice in which expression of the B7-1 costimulator was targeted to basal keratinocytes by using the human K14 promoter. Keratinocytes from the K14/B7-1 transgenic line expressed high levels of surface B7-1. No spontaneous inflammatory changes were seen in transgenic skin, but epicutaneous application of contact sensitizers to these mice elicited a stronger primary ear swelling response than in controls. Sites of initial hapten application in transgenic mice also responded much more strongly to reapplication of hapten to a remote cutaneous site. Epidermal cell suspensions from transgenic mice contained normal numbers of Langerhans cells and dendritic epidermal T cells when analyzed by flow cytometry. Systemic treatment of the transgenic mice with interferon gamma induced high levels of class II major histocompatibility complex expression on keratinocytes but was not sufficient to initiate an inflammatory response. We conclude that the constitutive expression of the B7-1 molecule in vivo on a nonprofessional antigen-presenting cell is not by itself sufficient to trigger inflammatory changes, but B7-1 expression amplifies the host immune responses after exposure to nonself antigens presented by B7-1-expressing cells.