摘要:

Percutaneous nicotine administration induces predominant sudorific and rubiform responses in the skin which may be accompanied by subtle piloerection, hyperalgesia and pruritus (although these signs are not overtly manifest). These dermal responses are complex and mechanisms have been proposed for the direct nicotine-stimulation of sweat glands, piloerection and vasoconstriction. These reactions are accompanied by secondary activation and release of vasodilator peptides which produce a predominating vasodilator tone following topical administration, this response masking the direct axon reflex-mediated vasoconstriction.

ISSN:1660-5527    

DOI:10.1159/000211021

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

24 healthy volunteers with no history of skin disease were entered in a 6-week double-blind randomized study to compare the atrophogenicity potentials of both cream and ointment forms of triamcinolone acetonide and clobetasol propionate. The atrophogenicity potential of cream preparations turned out to be greater than that of ointment preparations containing identical amounts of the same glucocorticoid. This result proves both the reproducibility of the assay and the general character of the phenomenon in view of the limited previous evidence.

ISSN:1660-5527    

DOI:10.1159/000211022

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Histamine-induced changes in blood flow in normal human skin were assessed by laser-Doppler velocimetry using 2 lasers of different wavelengths: 780 nm infrared and 633 nm helium-neon. The visible flare response in skin was also measured by planimetry. Laser-Doppler velocimetry was shown to detect both the magnitude of the change in blood flow caused by histamine and also the extent of the changes in the skin. Both parameters were related to the dose of histamine, which ranged between 25 and 750 pmol/site. There was good correlation between the magnitude of the histamine-induced blood flow change and the extent of the response. The flare induced by histamine and measured by planimetry was similar in extent to the blood flow change recorded by laser-Doppler velocimetry. No difference in either the magnitude or the extent of blood flow changes in response to histamine, as measured by laser-Doppler velocimetry, were found when lasers of different wavelengths were used.

ISSN:1660-5527    

DOI:10.1159/000211023

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Topical application of calcitriol or its analogs is a new approach for treating psoriasis, but may be limited by systemic calcitropic effects. Calcipotriol (MC 903) is a novel calcitriol analog with low calcitropic potency after systemic application. To compare the topical potency of calcitriol and calcipotriol we applied the two drugs on the right flanks of hairless rats for 10 days. In concentrations of 0.001-0.01 g/100 ml (ethanol) the two drugs are equally effective in inducing changes in the horny layer of the skin (increase in the amount of horny material that is able to be desquamated). This can be interpreted as a stimulation of terminal keratinocyte differentiation. However, only calcitriol caused a significant rise in the serum calcium concentration. In conclusion, calcitriol and calcipotriol seem to be equally effective after topical application on the skin of hairless rats, but calcipotriol has a much lower systemic calcium liability.

ISSN:1660-5527    

DOI:10.1159/000211024

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The inhibitory effect of the two H1 antagonists clemastine and loratadine on histamine release in human skin was studied in 15 volunteers. The antihistamines and placebo were administered orally (clemastine 2 mg twice a day, loratadine 10 mg once a day) for 5 days according to a double-blind, crossover design. Clemastine caused a significant sedation in comparison with placebo, whereas there was no difference between loratadine and placebo in this respect. After 5 days’ medication, flare reaction was induced by intradermal injection of histamine and the histamine liberator compound 48/80. The antihistamine dosages were approximately equipotent and inhibited the flare response induced by histamine to about the same extent, whereas the flares induced by compound 48/80 were still more inhibited by both drugs. The results indicate that clemastine and loratadine not only inhibit histamine effects at H1 receptor level, but have additional suppressive effects, probably due to inhibition of mast cell degranulation. The simple, virtually noninvasive, in vivo technique described in this paper does not require chemical analysis of the released mediators and could be used to screen ‘mast cell stabilizing’ effects of various antihista

ISSN:1660-5527    

DOI:10.1159/000211025

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The importance of the transappendageal route on percutaneous absorption was assessed in the hairless rat. Skin permeation of two steroids, hydrocortisone and testosterone, was evaluated in vivo on normal and artificially damaged skin in which follicles and sebaceous glands disappeared during healing. The test compounds were applied for periods of 0.5,2 and 6 h. Thereafter, the stratum corneum reservoir function, the epidermal and dermal distribution profiles, and systemic absorption were determined for both molecules. The results presented here show that the reservoir function of the stratum corneum of appendage-free (scar) skin is more pronounced than that of normal skin, whereas the concentration appearing in the epidermis and dermis was greater in normal skin. Moreover, sebaceous glands probably contribute to the penetration of hydrocortisone and testosterone. We show that the relative importance of the skin appendages depends on the intrinsic physical properties of the molecules tested, and the time of application.

ISSN:1660-5527    

DOI:10.1159/000211026

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

It is a general rule that percutaneous absorption is increased when the site of application is occluded. In this study we compared the in vitro permeation profiles of two molecules with different physicochemical properties under occluded versus unoccluded conditions. Human abdominal skin samples were mounted on Dianorm® Teflon® macro 1 cells and Franz diffusion cells which represented occluded or unoccluded conditions, respectively. Our data show that occlusion increased the permeation of citropten (lipophilic compound) 1.6 times whereas that of caffeine (amphiphilic compound) remained unchanged. This lack of penetration enhancement under occluded conditions has also been observed by other authors, especially concerning hydrophilic and slightly lipophilic molecules. Our results support the view that occlusion does not necessarily increase the percutaneous absorption of a chemica

ISSN:1660-5527    

DOI:10.1159/000211027

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

To identify minoxidil target cells in hair follicles we followed the uptake of radiolabeled drug in mouse vibrissae follicles both in vitro and in vivo. Autoradiography showed that both 3H-minoxidil and 3H-minoxidil sulfate accumulated in the differentiating epithelial matrix cells superior to the dermal papilla, a distribution similar to that of pigment. Minoxidil localized in melanocytes, melanocyte processes, and areas of greater melanin concentrations within the epithelial cells. Although uptake of minoxidil was significantly less in unpigmented follicles, the drug stimulated proliferation and differentiation of both pigmented and unpigmented follicles. Labeled minoxidil bound to Sepia melanin and was displaced with unlabeled minoxidil and other electron donor drugs. This interaction with melanin acts as a targeting mechanism of minoxidil to pigmented hair follicles but has no apparent functional significance in hair growth. This work illustrates how measurement of drugs in hair may be biased by pigmentation.

ISSN:1660-5527    

DOI:10.1159/000211028

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The antibiotic erythromycin is used topically in the treatment of acne vulgaris. In order to evaluate the in vivo cutaneous absorption behavior of erythromycin in man, an analytical procedure for erythromycin in stratum corneum tape strips was developed. Erythromycin was extracted from tape strips using solid-phase extraction, followed by alkaline diethyl ether extraction. Reconstituted extracts were analyzed by RP-HPLC with electrochemical detection. This procedure proved to be adequate in a pilot experiment in man, topical erythromycin appearing to be distributed over the stratum corneum, its upper layers displaying an inward decreasing gradient.

ISSN:1660-5527    

DOI:10.1159/000211029

出版商:S. Karger AG    

年代:1992

数据来源: Karger