ISSN:1660-5527    

DOI:10.1159/000211383

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Our previous studies revealed that topical minoxidil induced an increased rate of DNA synthesis in both dermal papilla and follicular germinal cells in early anagen and bulbar matrix as well as outer root sheath and perifollicular fibrocytic cells in mid and late anagen follicles in the bald scalp of the stump-tailed macaque. However, the epidermis and dermal fibrocytes showed no response. To determine the specific action of hypertrichotic agents on follicular cells, we examined the effects of two potent hypertrichotic agents, minoxidil and cyclosporin, on the DNA synthesis of cultured cells derived from either follicular cells (dermal papular, perifollicular fibrocytic and outer root sheath cells) obtained from human and macaque scalps or nonfollicular cells (fibrocytes and epidermal keratinocytes) from human and macaque foreskin, palm and sole regions and the 3T3 cell line. Cultured subconfluent cells from the above follicular and nonfollicular specimens were incubated with either minoxidil (0.01-2 mM) or cyclosporin (0.01-100 mM) in medium (serum-free DMEM) for 48 h, then 3H-fhymidine was added for the final 6 h. Minoxidil induced a significant increase in DNA synthesis in all follicular cells in a dose-specific manner (maximum rate at 0.5 mM for dermal papilla and perifollicular fibrocytic cells and 0.1 mM for outer root sheath cells). The perifollicular fibrocytic cells appeared to have a potentiality similar to that of the dermal papilla cells. Nonfollicular cells showed no response to minoxidil; 3T3 cells were rather suppressed. Cyclosporin appeared to have rather suppressive effects on both follicular and nonfollicular cells. These results suggest that minoxidil has a specific affinity to hair follicular cells and induced their cell proliferation. Although cyclosporin is known as a potent hypertrichotic agent, our studies on cultured follicular cells showed no direct proliferative effect. The hypertrichotic mechanism of cyclosporin appeared to be different from that of minoxidil.

ISSN:1660-5527    

DOI:10.1159/000211384

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

A model is described for evaluating the activity of a retinoid based on its effect on the keratinization of the vaginal epithelium that occurs on estrus (day 4) of a 4-day cycle in female rats. This keratinization process is dependent on the endogenous estradiol (E2) secreted between the evening of diestrus 2 (day 2) and that of proestrus (day 3). Various doses of all-trans-retinoic acid (tRA) were injected at different time points during the estrous cycle and the vaginal keratinization was assessed by microscope examination of unstained native or Papanicolaou-stained smear preparations. Additionally, the preovulatory E2 secretion was measured and ovaries were histologically examined. A single injection of 10 mg/kg tRA either on diestrus 2 (evening) or on proestrus (early morning) was able to induce a complete inhibition of the vaginal keratinization in more than 80% of the cases. This can be considered as a direct effect on the vaginal epithelial differentiation since neither the E2 secretion nor the ovulatory process were affected. The inhibition of vaginal keratinization can be used as a rapid and convenient in vivo model for screening retinoid candidates with antikeratinizing activity.

ISSN:1660-5527    

DOI:10.1159/000211385

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The purpose of these studies was to compare directly the percutaneous absorption, excretion and metabolism of all-trans-retinoyl β-glucuronide (RAG), a nontoxic retinoid, with all-trans-retinoic acid (RA) in the rat. Previously, it was demonstrated that topical treatment of human acne with either RAG or RA in cream resulted in a significant reduction of lesions. Whereas 0.1 % RA showed adverse effects, concentrations of RAG up to 2.4% did not cause any adverse reactions. In the present studies, radiolabeled RAG or RA, dispersed in a water-based cream, was applied to the shaved dorsal skin of vitamin A-sufficient rats. Both RAG and RA were absorbed from the skin in a similar way. In both cases, radioactivity peaked in the plasma within 2-4 h and within the liver at 4-12 h. During a 7-day period, the overall excretion of radioactivity derived from RA and RAG in the feces and urine were similar, e.g. 17 and 12%, respectively. It is concluded that: (1)the transport, metabolism and excretion of topically applied radioactive RA and RAG are similar, although not identical, in the rat and (2) the toxic skin manifestations induced by RA but not by RAG cannot be attributed to major differences in their overall absorption, metabolism and excretion.

ISSN:1660-5527    

DOI:10.1159/000211386

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Although retinoids may exert their action via binding to nuclear retinoic acid receptors (RARs), other mechanisms of action are not excluded. For example, the anti-acne drug, isotretinoin, lacks affinity for the receptors, but is a very potent inhibitor of endogenous vitamin A metabolism in human epidermal cells. To further extend this observation, we studied the effect of 12 different retinoids on the metabolism of [3H]retinol ([3H]ROH) in HeLa cells, previously shown to produce constant levels of 3,4-didehydroretinol (ddROH). The cells were cultured in the presence of the unlabeled retinoids for 20 h, followed by 4 h incubation with [3H]ROH. The accumulation of [3H]ROH and [3H]ddROH in cellular extracts was analysed by HPLC. Addition of 10-10 to 10-5M of four naturally occurring isomers of retinoic acid caused a 4- to 6-fold increase in [3H]ROH accumulation and an 80% decrease in [3H]ddROH. Addition of synthetic retinoids with a terminal carboxyl (CD270, CD271, CD367 and Ro 13-7410) decreased the [3H]ddROH accumulation with about 70%, but hardly at all affected the accumulation of [3H]ROH. We conclude that cultured HeLa cells appear to be useful for screening retinoids for their effects on vitamin A metabolism showing that a terminal carboxylic acid is a prerequisite for any major effects on metabolism to occur. Whether this effect is due to interaction with RARs or to competitive inhibition of vita-min-A-metabolizing enzymes demands to be studied.

ISSN:1660-5527    

DOI:10.1159/000211387

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Comparative testing of seven wound dressings (WD) has been performed with human HaCaT keratinocyte and mouse 3T3 fibroblast cultures. To assess biocompatibility, morphologic examinations were combined with cell counting. Supernatants were subjected to measurements of tissue peptide antigen (TPS), soluble intercellular adhesion molecule 1 (ICAM-1), and interleukins (IL-1α, -1β, -6). Furthermore, monoxygenation, the reduced glutathione/oxidized gluthathione (GSH/ GSSG) ratio and lipid peroxides were determined. Initial morphologic events were noted within the first day of exposure to WD. After 72 h, inhibition of cell growth was observed in the presence of hydrocolloids and hydrogels. The cytochrome-P-450-dependent ethoxyresorufin 0-deethylation rate and the GSH/GSSG ratio were not altered by WD in HaCaT cells. Lipid peroxide generation, IL-1 and ICAM-1 were scarcely detectable. TPS and IL-6 release indicate the presence of an ‘activated stage’ of keratinocytes and fibroblasts exposed to WD. Peptide release in vivo may contribute to the beneficial effects of modern dressings in the treatment of superficial cutaneous wounds.

ISSN:1660-5527    

DOI:10.1159/000211388

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Copper and zinc percutaneous absorptions were assessed in vitro using sliced human skin and both petrolatum and hydrophilic gels as vehicles. Applied quantities were largely in excess for the duration of the experiment (72 h). The absorption of sulphates and chlorides was compared. The cumulated amount recovered in receptor fluid was below 50 μg/cm2. The apparent permeability constant values kept in the range of 10-6 cm h-1, except for ZnCl2 in gel vehicle (2.9 10-5 cm h-1). With the exception of CuCl2 in gel vehicle, chlorides gave higher absorption rates than sulphates. This can be related to the higher octanol-water partition coefficient of chlorides. Storage within the epidermis was found to be equal to or greater than, and within the dermis equal to or lower than the 72-hour cumulative amount in receptor fluid. No difference was found in this respect between copper and zinc. This work confirms the poor absorption of electrolytes through normal human skin, whatever the vehicle used.

ISSN:1660-5527    

DOI:10.1159/000211389

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

In the present study we have investigated the effects of diethylene glycol monoethyl ether (Transcutol®) in combination with theophylline, caffeine and dyphylline and alone on 3T3 mouse fibroblast proliferation. These three xanthines (1-0.01 mM) inhibited fibroblast proliferation by themselves. Enhancement of the effect was detected by addition of 1 and 0.1 mM Transcutol. Transcutol alone also displayed a dose-dependent inhibition (2-0.01 mM) of both 3T3 and human normal and psoriatic fibroblasts, although normal human fibroblasts were the least sensitive to Transcutol antiproliferative activity. Transcutol was assessed for its antiproliferative effects on YAC lymphoma and P-815 mastocytoma human cell lines. Transcutol inhibited cell proliferation of both these cell lines, being more effective towards P-815 mastocytoma (at 2 mM it displayed 3.95-fold vs. 2.4-fold inhibition towards YAC lymphoma). In conclusion, we have shown that Transcutol has antiproliferative effects on 3T3 murine, human normal and psoriatic fibroblasts and tumour cell lines. In addition it enhances xanthine antiproliferative effects on 3T3 fibroblasts. Therefore it might be a useful topical drug alone or in combination with xanthines in the treatment of skin hyperproliferaive disorders

ISSN:1660-5527    

DOI:10.1159/000211390

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Previously, we described methods for measuring in vivo antimicrobial activity in which the resident bacterial flora of the forearm is expanded by occlusion with an impermeable plastic film, test agents are applied and quantitative cultures are obtained at varying time points. This methodology allows for an in vivo quantitative assessment of antimicrobial effects directed against a dense flora comprised primarily of staphylococci. This method may not be applicable to situations in which there is a high density of multiple species of bacteria. We describe herein new methods which permit in vivo determination of antimicrobial activity against a dense, mixed flora. Swabs moistened with a dilute nonionic detergent are used to remove bacteria from the subject’s axilla or groin which are then translocated to the subject’s forearm. Occlusion of the forearm with a large, sterile plastic chamber provides the necessary humid environment to yield a dense flora (105–106 CFU) consisting of gram-positive cocci, gram-positive coryneforms and gram-negative rods. In this manner, multiple test sites are created on each forearm allowing for the simultaneous evaluation of multiple antimicrobial agents in a single subject. This method allows for the evaluation of the immediate, as well as sustained, in vivo bactericidal effect of an antimicrobial agent against a dense mixed flora with quantitative cultures obtained at varying time points after application of the test agent. Furthermore, ecological pressures which select for resistant organisms or allow for an overgrowth of nonsensitive bacteria can be evaluated by determining the composition of the flora after single or repeated applications of a test agent. The testing methodologies described herein can provide relevant information regarding the antimicrobial effectiveness of an agent in a variety of situations such as use against the axillary flora (including its utility as a deodorant), use as a perineal cleanser for critically ill, hospitalized patients and use in situations where a dense mixed flora exists, e.g. stasis ulcers and infected intertriginous dermatoses.

ISSN:1660-5527    

DOI:10.1159/000211391

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Skin surface stripping with adhesive tape has been used to study the barrier function of the stratum corneum. Usually, the amount of stratum corneum removed by stripping is not linearly proportional to the number of strips removed. The generally accepted quantitative method to determine the amount of stratum corneum material on a tape strip is weighing. This method however has certain drawbacks, it is time consuming and laborious because tape strips have to be weighed twice and sometimes it cannot be used to determine concentration profiles in the skin of active substances in topically applied vehicles. In this paper, the accuracy and reliability of an alternative method to determine the amount of stratum corneum removed by tape stripping of the skin was investigated and compared to weighing. It is based on the spectrophotometric examination of the tape. The light absorption by the proteins on the tape is correlated to the weight of the stratum corneum material. This method was found to be easier and faster than weighing, but it was less reliable because the light scattering of the stratum corneum on the tape largely overshadowed the absorption of the proteins. The light scattering showed a linear increase with an increasing amount of material on the tape, but with a large variability, resulting in calibration curves with correlations of 0.8400. However, direct spectroscopic analysis of stratum corneum tape strips has some distinct advantages even if it cannot be used for the exact quantification of stratum corneum proteins. With direct spectroscopic measurements, a tape strip can be laterally examined to inspect its homogeneity. Direct spectroscopic measurements on tape strips might also be employed to investigate the lateral and in-depth distribution of strongly light-absorbing substances in the stratum corneum.

ISSN:1660-5527    

DOI:10.1159/000211392

出版商:S. Karger AG    

年代:1996

数据来源: Karger