Epidermal Cell Proliferation in Guinea Pigs with Experimental Dermatophytosis

To elucidate the mechanisms underlying the self-healing process of experimental dermatophytosis produced in guinea pigs by an occlusive method with Trichophyton mentagrophytes, epidermal proliferative activity was evaluated by the in vivo tritiated thymidine-labeling technique performed at various intervals after the first and second infections. Determination of labeling indices disclosed that an increased epidermal proliferation correlated well with the severity of inflammatory changes, i.e., a peak activity was noted after 10 days in primary infection and at 2 days in reinfection, respectively, and was followed by subsequent spontaneous lesion clearance after 10 days. Application of a heat-killed spore suspension produced inflammatory changes with enhanced epidermopoiesis, similar to those induced by reinoculation of living spores, only in immune animals. The present results indicate that the dermatitic changes occurring in experimental dermatophytosis increase epidermopoiesis which facilitates elimination of the fungus from the stratum corneum and that host immune activity, particularly contact sensitivity to fungal antigen, exerts a crucial role to induce these changes

Alteration in Murine Epidermal Langerhans Cell Population by Various UV Irradiations: Quantitative and Morphologic Studies on the Effects of Various Wavelengths of Monochromatic Radiation on Ia-Bearing Cells

The present study was undertaken in order to clarify the exact mode of the Langerhans cell (LC) depleting process caused by UV irradiation. Following irradiation with a single dose of various wavelengths of monochromatic UV radiation (UVR), we studied the number of Ia-positive cells in mouse epidermal sheets quantitatively, particularly with regard to dose-response relationship, action spectrum, and time course change. In addition, we studied morphologic alterations of these cells using electron- and immunoelectron microscopy (EM and IEM).We obtained the following results after a single dose of UVB radiation (200 mJ/cm2 of 300 nm) or PUVA (1% of 8-methoxypsoralen (8-MOP) 20 μ1 and 1 J/cm2 of 360 nm): (1) EM and IEM showed that while some LCs simply lost their Ia marker without any structural alterations, the majority of the LCs disappeared due to actual cell damage. (2) During an ‘injury phase,” the initial 48 h, and a “recovery phase,” lasting from 4–14 days after irradiation, enlargement of the size of remaining Ia-positive LCs occurred. The degree of enlargement was closely related to the degree of reduction in number, suggesting a process compensating for the loss of the LC population. (3) It was found that the recovery rate of LCs after irradiation damage was slower than that of keratinocytes, indicating different cell kinetics between these distinct cell populations in the epidermis, i.e., restoration of LCs after irradiation seems to be achieved at least partially through a repopulation process originating in the bone marrow.Studies with irradiation of various monochromatic wavebands, with or without topical 8-MOP, showed that the action spectrum for Ia-positive cell depletion activity lay within the spectrum shorter than 300 nm for UVR alone, and between 320–380 nm for 8-MOP plus UVR. Since the action spectra were similar to those for keratinocyte damage, i.e., sunburn cell formation, induction of unscheduled DNA synthesis, and to those for UVR-induced erythema, we conclude that common mechanisms underlie these types of tissue damage

Determination of Anaphylatoxin Concentrations in Suction Blisters in Patients with Psoriasis

Concentrations of C3a and C4a anaphylatoxins in suction blister fluids were determined by radioimmunoassay in patients with psoriasis and normal controls. Comparison of anaphylatoxin levels between serum samples and blister contents in the same subjects revealed that the levels of both C3a and C4a anaphylatoxins were significantly higher in the former than the latter even in those raised on normal skin, suggesting that the classic complement pathway is activated during suction procedure. Therefore we cannot regard suction blister fluid to be simply representative of undisturbed interstitial tissue fluid as far as the complement system is concerned. There was no difference in anaphylatoxin levels between those from uninvolved skin of psoriatic patients and those from normal controls. However, significantly high anaphylatoxin levels were noted in fluids of suction blisters raised on lesional skin as compared with those produced on uninvolved skin in psoriatic patients

Successful Treatment of Cutaneous Botryomycosis with a Combination of Minocycline and Topical Heat Therapy

Cutaneous botryomycosis is a chronic focal infection characterized by a granulomatous inflammatory response to bacterial pathogens such as Staphylococcus aureus. Treatment requires antibiotic therapy and may also require surgical debridement. We employed topical heat therapy and oral minocycline. The lesions became flattened and pigmented after 1 month. We consider that this simple treatment can be an effective and harmless complementary therapy for cutaneous botryomycosis

Malignant Fibrous Histiocytoma with In-Transit Metastasis

Malignant fibrous histiocytoma (MFH) is the most common fibroblastic tumor, but its cutaneous metastasis, especially in-transit metastasis, is extremely rare. We describe the case of a 30-year-old Japanese man with a recurrent MFH on the scalp accompanied by in-transit metastasis, which had been treated as a benign skin tumor 8 years before. The main bulk of the recurrent tumor was located in the dermis, but the metastatic tumor was mainly located in the subcutis. Generally, atypical fibroxanthoma, also known as cutaneous MFH, is rarely metastasized and presents a benign clinical course. Since there is a great difference between the prognosis of MFH and atypical fibroxanthoma, precise diagnosis of the primary tumor is essential

Role of Complement in Chlorpromazine-Induced Phototoxicity

To evaluate the role of the complement system in inflammation induced by chlorpromazine (CPZ) and ultraviolet-A (UVA) irradiation, the phototoxic response in guinea pigs decomplemented by cobra venom factor was compared with that in saline-treated animals. Phototoxic lesions were induced in animals by intradermal injections of CPZ solution, followed by UVA irradiation. Clinically, the normal animals developed erythema and induration which showed a maximal response at 10h with a mean value of 1.6 on a scale of 0 to 3 +. The complement-depleted animals showed a weaker clinical response than the normal animals 6-24h postirradiation (p < 0.05). These clinical changes were associated with increased vascular permeability, as demonstrated by extravasation of i. v. injected Evans blue in saline-treated animals. In vitro UVA irradiation of serum containing CPZ resulted in a dose-dependent diminution of total complement activity. Such irradiated serum showed immunoelectrophoretic C3 conversion. These results suggest that the complement system is involved in the development of CPZ-induced phototoxic lesions