摘要:

Cellular retinoic acid binding proteins (CRABP) are cytoplasmic proteins that bind all-trans-retinoic acid (RA) and other retinoids. The purpose of these studies was to determine the effects of topically applied RA on CRABP expression in rhino mouse skin. CRABP-II mRNA was significantly induced (3-to 4.5-fold) by a single dose of RA at 6 and 16 h after RA treatment, with a return to control levels at 48 h. CRABP-II message was not significantly elevated by 3 or 4 consecutive days of RA treatment, when assessed 24 h after the last treatment. CRABP-I mRNA was undetectable in control and RA-treated skin. We used radiolabelled RA binding combined with non-denaturing PAGE blot autoradiography to distinguish the CRABP subtypes. By this protein assay method, increases in CRABP-II were detected 24 and 48 h after a single application of RA, as well as after 3 and 4 days of RA treatment. RA treatment did not alter CRABP-I expression relative to the vehicle control. These results demonstrate that in mouse skin CRABP-II, but not CRABP-I, is inducible by RA, and is similar to how RA regulates CRABP in human skin.

ISSN:0302-3427    

DOI:10.1159/000211342

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Salicylic acid (SA) and urea are widely used in topical preparations. Using a simple tape stripping technique the effect on the binding forces within the stratum corneum and the skin absorption of SA and urea were studied. The degree of stratum corneum removal was recorded by measuring the transmission through the tape with a digital light-measuring instrument. With successive stripping of the skin the amount of tissue adhering to the tape decreased. Exposure of the upper arm to 2% SA for 6 h increased the skin material on the tape strips significantly. No significant increase was recorded after 3-hour exposure, or after exposure to 0.5% SA. Neither did the exposure to 10% urea for 3 or 6 h influence the amount of skin adhering to the tape significantly. Radiochemical analyses showed that the amount of SA and urea in each of the first 6 tape strips was about 5-15 μg/cm2. This technique provides a useful tool to evaluate the binding forces within the stratum corneum in relation to absorption of topically applied substances

ISSN:0302-3427    

DOI:10.1159/000211343

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

A vital function ofthe skin is to oppose the loss of water to the environment. In this study, two complementary methods, transepidermal water loss (TEWL) and continuous electrical capacitance under occlusion, were used to assess epidermal barrier function in a developmental animal model, the neonatal Sprague-Dawley rat. TEWL monitors barrier function directly while the increase in capacitance under occlusion is related to both the skin’s barrier function and to its water holding capacity. Serial tape stripping of the stratum corneum on 1-day-old rat pups led to a significant increase in both TEWL and continuous capacitance measurements. Anatomic site heterogeneity and the effects of surface temperature were also studied. The ventral skin surface exhibited an increase in the continuous capacitance measurements, an effect possibly due to the thinner stratum corneum on the ventral side. Both TEWL and continuous capacitance values were directly correlated with ambient temperatures within the physiological rang

ISSN:0302-3427    

DOI:10.1159/000211344

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The measurement of transepidermal water loss (TEWL) is an important noninvasive method in order to assess the barrier function of the stratum corneum. As a consequence, TEWL has been found to be a very useful technique for studying skin irritation induced by various physical and chemical effects. Exposure of the skin to chemicals (detergents) and physical conditions (occlusion and stripping) generally results in an increase of TEWL. Until recently the only commercially available TEWL instrument was the Evaporimeter® developed by ServoMed (Sweden). The instrument is based on the open chamber system with two humidity and temperature sensors which measure the water evaporation gradient at the surface of the skin. Recently a new commercially available instrument based on the same physical principle of measurement was developed by Courage and Khazaka (Tewameter®, FRG). Our aim in this study has been to compare the measuring capacities of both instruments. The accuracy, sensitivity, variability and reproducibility of both instruments were compared in vivo under identical conditions on normal skin and skin damaged by external conditions. The influence of external and environmental factors such as air and probe temperature, relative humidity, air turbulence and pressure of application was evaluated for both instruments. Finally, the two instruments were compared in practice when following the increase in TEWL of the skin after stripping, occlusion and exposure to irritant household detergents. A very good correlation (r = +0.97) was found between the results of the two instruments over a wide range of TEWL value

ISSN:0302-3427    

DOI:10.1159/000211345

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Dapsone (4,4’-diaminodiphenylsulfone) is effective in treating inflammatory skin diseases. Several lines of evidence suggest that the anti-inflammatory properties of this sulfone are partially due to modulation of functions of polymorphonuclear leukocytes (PMN). The goal of the present investigation is therefore to ascertain possible inhibitory effects of dapsone upon human 5-lipoxygenase (5-LOX) pathway. PMN of healthy donors were pretreated with dapsone in different concentrations (1.6-100 μM) for 5 min following by adding Ca ionophore A 23187 (10 μM) and subsequent incubation for 10 min. Thereupon the eicosanoids were assessed by reversed-phase high-performance liquid chromatography (RP-HPLC). Dapsone exhibited dose-dependent inhibitory activity showing 50% inhibition at 15 μM for leukotriene B4 (LTB4) with 5 × 106 PMN. The IC50 (half maximum inhibition concentration) of dapsone for 5-hydroxyeicosatetraenoic acid (5-HETE) and ω-OH-LTB4 amounted to similar values (5-HETE: 9 μM; (ω-OH-LTB4: 11 μM). The inhibition of the conversion of arachidonic acid to several eicosanoids mainly suggests an effect on the 5-LOX enzyme. The comparison of inhibition values between intact PMN and a cell-free system (by sonification) indicates an additional effect of dapsone upon enzymes other than 5-LOX. Since the concentrations used are comparable with therapeutic conditions, dapsone may exert part of its anti-inflammatory effect by prevention of the generation of 5-LOX met

ISSN:0302-3427    

DOI:10.1159/000211346

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The hamster flank organ model was used to measure the effects of clofibric acid on the in vitro uptake of sodium [1-14C] acetate into lipids. Clofibric acid produces a dose-dependent inhibition of lipogenesis in the hamster flank organ in vitro.

ISSN:0302-3427    

DOI:10.1159/000211347

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

In order to study a possible association between skin thickness and osteoporosis, we measured skin thickness by A mode ultrasound scanning in 20 females with osteoporosis and 20 age- and sex-matched controls. Bone mineral content (BMC) of the lumbar spine and the forearm was measured by dual-photon absorptiometry. BMC of the lumbar spine was significantly reduced in the osteoporotic group as compared to controls (p < 0.002). No difference in skin thickness was found between osteoporotic patients and controls. A statistically significant correlation between skin thickness on the forearm and BMC of the forearm was found (p < 0.02), but was opposed by a lack of correlation between skin thickness and BMC of the lumbar spine. We found a correlation between skin thickness and body weight (p < 0.002), which to our knowledge had not been reported earlier.

ISSN:0302-3427    

DOI:10.1159/000211348

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Investigations on croconazole, a novel imidazole compound, suggested antiphlogistic properties in vitro. Hence, its anti-inflammatory capacity was tested in vivo using the arachidonic acid-induced mouse ear swelling test, which is a suitable model for screening inhibitors of the lipoxygenase and/or the cyclooxygenase. Topical application of croconazole (1%/ 0.01 %) to the mouse ear induced a maximal inhibition of edema (inhibition: 39%/33%; p = 0.01) which was as strong as the reference nordihydroguaiaretic acid (inhibition: 38.9%; p = 0.01). These results justify further investigations on croconazole to study potential inhibitory effects on proinflammatory arachidonic acid metabolites.

ISSN:0302-3427    

DOI:10.1159/000211349

出版商:S. Karger AG    

年代:1995

数据来源: Karger