Clinical trial: the safety of terbinafine in patients over the age of 60 years: a multicenter trial in onychomycosis of the feet.

Thirty patients completed this open-label, multicenter prospective study performed to evaluate the efficacy and safety of terbinafine treatment of onychomycosis of the feet in elderly patients. Inclusion criteria included an age of 60 years or older, a diagnosis of onychomycosis confirmed by positive potassium hydroxide (KOH) preparation at baseline, and toenails capable of regrowth. Patients were excluded from the study if they had received any systemic antifungal therapy within the previous 3 months or topical antifungal therapy within 1 week prior to the start of the study; had psoriasis; had toenail abnormalities interfering with normal toenail appearance; were immunosuppressed or immunodeficient; or had serum hepatic enzyme (serum glutamic-oxaloacetic transaminase, SGOT; serum glutamic-pyruvic transaminase, SGPT) values greater than 1.5 times the upper limit of normal at baseline. Following baseline evaluations, eligible patients received a 12-week supply of oral terbinafine (250 mg/day) for self-administration. Compliance was assessed by tablet counts at each visit and defined as the use of at least 80% of the medication prescribed at the first two visits. Follow-up evaluations were conducted for the next 60 weeks, for a total study period of 72 weeks. These visits occurred at weeks 6, 12, 24, 36, 48, and 72. All follow-up visits included: (i) the reporting of adverse effects; (ii) assessment of efficacy by KOH preparation, mycologic culture, and investigator evaluation; and (iii) physician and patient global assessments of various quality of life parameters (except for the visit at week 36). Safety and tolerance were assessed by physical examination at baseline and week 12, by laboratory evaluations (hematology, blood chemistry, and urinalysis) at baseline, week 6 and week 12, and by reporting and evaluation of adverse events throughout the entire study. Investigators assessed the extent of involvement of the target toenail and recorded global assessments of therapeutic efficacy at all visits. Mycologic evaluation was conducted by KOH preparation and a mycologic culture of the target toenail. Because of discrepancies in KOH results between the investigator sites and the central laboratory in early analyses, we chose to use the mycologic culture results to evaluate efficacy. Because all 30 subjects were treated with terbinafine, the entire group was considered for safety evaluation.

UVB induces atypical melanocytic lesions and melanoma in human skin.

A direct causal relationship between ultraviolet (UV) light in the B range and melanoma development has not been demonstrated in humans; this study aims to establish causality. A total of 158 RAG-1 mice, grafted with human newborn foreskin, were separated into four groups and observed for a median of 10 months: 1) no treatment, 2) a single treatment with 7,12-dimethyl(a)benzanthracene (DMBA), 3) UVB irradiation at 500 J/m2 alone, three times weekly, and 4) a combination of DMBA and UVB. Twenty-three percent of 40 normal human skin grafts treated with UVB only and 38% of 48 grafts treated with the combination of DMBA and UVB developed solar lentigines within 5 to 10 months of treatment. Melanocytic hyperplasia was found in 73% of all UVB-treated xenografts. Histological melanocytic changes resembling lentigo and lentigo maligna were seen in several skin grafts treated with both DMBA and UVB. In one graft of an animal treated with a combination of DMBA and UVB, a human malignant melanoma, nodular type, developed. This experimental system demonstrates that chronic UVB irradiation with or without an initiating carcinogen can induce human melanocytic lesions, including melanoma.

UVB induction of epithelial tumors in human skin using a RAG-1 mouse xenograft model.

To examine the effects of chronic ultraviolet light on human epidermal cells, we grafted white human skin onto recombinase activating gene-1 knockout mice. We found previously that the maximal concentration of ultraviolet B radiation (290-320 nm) tolerated by human skin xenografts was 500 J per m2 when given three times weekly. One hundred and fifty-eight grafted mice were randomized and observed for a median of 10 mo in four groups: (i) no treatment; (ii) one treatment with the chemical carcinogen dimethyl-(a)benzanthracene; (iii) ultraviolet B three times weekly; and (iv) a combination of dimethyl-(a)benzanthracene and ultraviolet B. Approximately half of the skin specimens treated with ultraviolet B developed superficial milia and epidermal cysts. Grafts contained up to seven milia lesions between 4 and 8 mo after initiation of treatment, whereas the number of larger epidermal cysts was rarely more than two. Milia and cysts developed in the skin regardless of pigmentation or tanning. Actinic keratoses arose in 9% of grafts treated with ultraviolet B alone and in 19% of grafts treated with the combination of dimethyl-(a)benzanthracene and ultraviolet B. Invasive squamous cell carcinomas developed in 10% of grafts after combined dimethyl-(a)benzanthracene and ultraviolet B treatment and lesions were restricted to skin grafts that did not tan. These findings demonstrate that (i) development of ultraviolet-induced lesions can be experimentally accelerated in human skin, (ii) xenografted recombinase activating gene-1 deficient mice are superior to severe combined immunodeficiency disease mice for chronic ultraviolet B studies, and (iii) benign cystic tumors and squamous cell carcinomas are caused by ultraviolet B.

Methotrexate induces differentiation of human keratinocytes.

Terminal differentiation is a key element in the maintenance of tissue homeostasis in the epidermis. We show here that methotrexate (MTX) induces differentiation of human epidermal keratinocytes in vitro. MTX inhibits proliferation of keratinocytes and also induces several markers of differentiation: a change in cell morphology, a marked increase in cell size, an increase in the proportion of cells that express involucrin, and an increase in the amount of cornified envelope protein. These effects of MTX are dose- and exposure-time-dependent and become irreversible after 24 hr, approximately one population doubling time. These effects of MTX cannot be attributed to cytotoxicity since keratinocytes not only remain viable but also actively synthesize proteins. MTX causes reproducible changes in the SDS/PAGE profiles of newly synthesized proteins and, in particular, increases the amount of involucrin synthesis. Thymidine completely prevents these effects of MTX, suggesting that they are caused by a depletion of thymine deoxyribonucleotides. The effect of MTX on keratinocytes may provide a model for studying the relationship between deoxyribonucleotide metabolism and differentiation in normal cells. In addition, the ability of MTX to induce differentiation in keratinocytes suggests a mechanism to explain its therapeutic action in psoriasis.