Archives of dermatological research
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Arch. Dermatol. Res. · Jun 1998
Randomized Controlled Trial Clinical TrialEffect of topical capsaicin on the cutaneous reactions and itching to histamine in atopic eczema compared to healthy skin.
Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide) is thought to produce analgesic and possibly also antipruritic effects when applied topically. Capsaicin 0.05% was applied three times daily over a 5-day period to the same infrascapular region. The effects of the pretreatment upon the pruritogenic and wheal and flare reactions to subsequent histamine iontophoresis (20 mC) were evaluated on the following day. ⋯ Itch sensations in capsaicin-pretreated skin were significantly lower in control subjects than in AE patients. We conclude that capsaicin does effectively suppress histamine-induced itching in healthy skin but has less effect in AE. The diminished itch sensations and the absence of alloknesis in atopic individuals indicate that histamine is not the key factor in itching in AE.
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Arch. Dermatol. Res. · Oct 1997
Intraepidermal nerve fiber expression of calcitonin gene-related peptide, vasoactive intestinal peptide and substance P in psoriasis.
In order to evaluate more fully the role of neuropeptides in the pathogenesis of psoriasis, skin biopsies were obtained from 36 patients with psoriasis to identify substance P (SP), vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP). Lesional and nonlesional skin was examined from these biopsies and the results compared with those from biopsies taken from patients with a variety of other inflammatory dermatoses, including lichen planus, lichen simplex chronicus, spongiotic dermatitis, and seborrheic dermatitis. Also studied was a series of nine biopsies taken from patients with no known skin disorders. ⋯ There was no significant difference in numbers of VIP- or CGRP-immunopositive intraepidermal nerve fibers between psoriatic skin and the group comprising all other material tested. However, in five patients with psoriasis, there was a marked increase in the expression of intraepidermal CGRP (up to 10.7 nerves per 3-mm biopsy) and VIP (up to 8.3 nerves per 3-mm biopsy) which was not observed in control groups. These findings suggest that neuropeptides SP, CGRP, and VIP play a role in the pathogenesis of psoriasis.
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Arch. Dermatol. Res. · Oct 1997
Role of transforming growth factor-beta 1 in fibroblasts derived from normal and hypertrophic scarred skin.
In order to elucidate the effect of transforming growth factor beta 1 (TGF-beta 1) on normal dermal fibroblasts (NDF) and on fibroblasts derived from hypertrophic scar (HSF) tissue, we compared proliferation, the levels of TGF-beta 1 protein and mRNA, the activity of type-I collagen synthesis and collagenase, and the response to recombinant human (rh) TGF-beta 1 in cultures of both types of cells which had been simultaneously collected from the same patients. We also studied the effects of anti-TGF-beta 1 antibody on the proliferation of these two types of fibroblasts in culture. In spite of the fact that the growth rate of HSF was higher than that of NDF, NDF proliferation was more sensitive to the concentration of rhTGF-beta 1. ⋯ In addition, the production of TGF-beta 1 and the expression of TGF-beta 1 mRNA in HSF were greater than in NDF. Furthermore, anti-TGF-beta 1 antibody reduced the rate of growth of HSF. These results suggest that HSF are able to produce TGF-beta 1, resulting in enhanced proliferation of these cells as well as in a rapid synthesis of type-I collagen through an autocrine mechanism which may lead to hypertrophic scarring.
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Arch. Dermatol. Res. · May 1997
Epidermal growth factor and temperature regulate keratinocyte differentiation.
The limited life-span and irregularities in epidermal differentiation and barrier function that have restricted the utility of presently available skin culture models for pharmacological and toxicological studies indicate that further modifications of culture conditions are required for optimization of these models. In the present study epidermis reconstructed on de-epidermized dermis was used to investigate the effects of temperature and epidermal growth factor (EGF) on epidermal differentiation and lipogenesis. When cultured at 37 degrees C, keratinocytes formed a well-differentiated epidermis whether EGF was present or not. ⋯ The synthesis of the early specific protein differentiation markers (keratins 1 and 10) was suppressed on both the protein and mRNA levels without significant interference with the synthesis of late differentiation lipid markers, such as ceramides. From this observation it can be concluded that the synthesis of keratins associated with terminal differentiation is profoundly affected by the presence of EGF and is sensitive to temperature and that of ceramides is not. The finding that TGF alpha did not modulate the morphogenesis and synthesis of keratins 1 and 10 in cultures grown at 33 degrees C indicates possible differences between the postreceptor binding processes of these EGF receptor ligands.
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Arch. Dermatol. Res. · Jul 1996
Randomized Controlled Trial Comparative Study Clinical TrialCorrelations between histamine-induced wheal, flare and itch.
Correlations between the skin reactions wheal and flare and the subjectively reported degree of itch were investigated in response to 1% histamine, intradermally applied by standardized skin prick and by iontophoresis. Experiments were performed with 15 male volunteers using a threefold repeated measures design (skin prick, and iontophoresis with 0.13 mA for 10 s and with 2.0 mA for 10 s). Skin reactions (perpendicular diameters) were determined at the time of their maximum (10 min). ⋯ Repeated measurements showed a higher stability for the itch reaction with skin prick compared with iontophoresis. It is hypothesized that in iontophoresis the brief (10-s) histamine bolus passed the most superficial pruritoceptive C fibres too quickly to induce long-lasting itch sensations, whereas the skin prick caused a deposit at the dermal-epidermal junction releasing histamine during the entire time of measurement. Consequently, both the C fibre-mediated itch and the axon reflex flare were more pronounced with the skin prick, and the wheal resulting from a permeability increase in the postcapillary venule walls was an independent phenomenon.