摘要:

To clarify the sources of variation in irritant patch testing, variability in delivery of the test substance from the patch test system was studied. An in vitro model was used to study the penetration of sodium lauryl sulphate (SLS) from a patch test system into the skin. Different formulations of SLS applied to the skin for 24 h were studied (aqueous solution and gels), but irrespective of the vehicle used permeation of SLS into the recipient phase was poor. Results were compared to in vivo patch testing in 12 subjects. Approximately 70% of the applied SLS in aqueous soltion was released from the patch test system. Release from gels was poorer. High concordance between the in vivo and the in vitro model was found. No correlation was found between the amount of SLS left in the filter disc and the strentgh of the clinical reaction in vivo.

ISSN:0302-3427    

DOI:10.1159/000210873

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

We characterized in vitro adsorption of representative chemicals in candidate gel/charcoal matrices being investigated for use in noninvasive transdermal chemical collection. Binding properties of three model compounds of widely varying water and lipid solubilities (theophylline, methotrexate, and parathion) were studied in hydrophilic (agarose, or polyvinyl alcohol/polyvinyl pyrrolidone) and lipophilic (silicone) gel/charcoal compositions. Analysis of adsorption isotherms indicate that agarose is the superior gel selection for hydrophilic compounds such as theophylline and methotrexate (greater than 90% uptake for each), and that a silicone lipogel allows for greatest lipophilic (parathion) adsorption (greater than 95% uptake).

ISSN:0302-3427    

DOI:10.1159/000210874

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

In vitro and in vivo skin permeability studies were conducted to investigate properties of several candidate transdermal chemical collection devices (TCDs). The TCD consists of a binding reservoir of activated charcoal suspended in a gel medium which is occlusively placed in direct contact with the skin. Binding of three model compounds (theophylline, methotrexate, and parathion) was studied in hydrophilic (agarose or PVA/PVP) and lipophilic (silicone) gel/carbon compositions. The effects of gel composition, compound hydrophilicity/lipophilicity, and hydration of skin on quantity of transdermally collected chemical and ‘apparent’ permeability were investigated using a ‘fuzzy’ rat animal model. In vitro and in vivo apparent permeability coefficients (Kp; cm/h) for amphophilic theophylline (6.95 0-4 and 8.34 10-4, respectively) and hydrophilic methotrexate (3.5 10-3 and 3.2 10-4, respectively) using an agarose aquagel TCD were greater than the corresponding Kp values obtained when silicone lipogel TCDs were employed (0.3 10-4 and 3.2 10-4, respectively, for theophylline; no measurable methotrexate was collected). Occlusive hydration of skin profoundly increased permeability of the hydrophyilic model compound, methotrexate. In vivo Kp values for lipophilic parathion were greater with a silicone TCD (6.7 10-4) than with an agarose TCD (3.8 10-4). We conclude that it is possible to influence transdermal chemical collection through modifications in the gel composition and by hydration of t

ISSN:0302-3427    

DOI:10.1159/000210875

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

In the present study the ultrastructural aspects of the migration of polymorphonuclear leukocytes (PMN) in apparently normal skin following the epicutaneous application of leukotriene B4 (LTB4) were studied and it was investigated whether this model is representative of the migration of PMN in psoriatic skin. At the ultrastructural level the following features were observed: degranulation of PMN, formation of fenestrations and gaps of the endothelium, a multilayered basal lamina and hyperactive endothelial cells with protrusions and focal necrosis of these cells. Epicutaneous application of LTB4 is a practical approach to study the dynamics of the interaction between PMN and the endothelium in vivo.

ISSN:0302-3427    

DOI:10.1159/000210876

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Four topical anti-inflammatory drugs were investigated for their effect on allergic contact dermatitis. Nickel dermatitis was chosen for its high incidence in European healthy volunteers. Experimental lesions were treated twice daily with two steroids, two non-steroidal anti-inflammatory drugs and a blank base for 4.5 days without occlusion. The influence of treatments was assessed by daily visual grading and one site was left untreated for comparison over the same period. To quantify drug activities objectively, skin colour (colorimetry), skin blood flow (laser Doppler velocimetry) and transepidermal water loss (evaporimetry) were measured before drugs were first applied, then 6 h after the last application. As expected, only Dermoval cream significantly improved the spontaneous clinical evolution in comparison with the other creams (Hydrocortisone Astier à 1 %, Parfenac, indomethacin 2.5% and Skinbase) and the untreated site. Colorimetric parameter a* (redness) and L* (luminance) showed more differences between treatments than the other criteria and a close relationship was obtained between these two parameters and skin blood flow, all three being highly correlated to visual grading. Transepidermal water loss appeared less related to clinical improvement but this parameter could prove helpful for detecting compounds which could be irritant to diseased skin

ISSN:0302-3427    

DOI:10.1159/000210877

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Retinoic acid and analogues (retinoids) are able to induce the differentiation of F9 murine embryonal carcinoma stem cells into endoderm-like cells. The secretion of plasminogen activator (PA) which accompanies this differentiation is a good index of the biological response of F9 cells to retinoids. We have previously reported that the potency of a series of natural and synthetic retinoids, evaluated by the concentration which provokes half-maximal induction of PA, correlates well with the affinity of these compounds for the endogenous F9 nuclear retinoic acid receptors, but not for the cytosolic retinoic acid binding protein, CRABP. In this paper we show that various retinoids differ, not only in terms of potency, i.e. the dilution at which they are active, but also in terms of the amount of PA that they induce. This parameter, called amplitude, is used to quantify the extent of PA induction by a given retinoid relative to retinoic acid. The amplitude parameters of synthetic retinoids are found to vary over a wide range and are independent of both potency and binding affinity for F9 retinoic acid receptors. It is proposed that the amplitude of the biological response to a given retinoid is the resultant of three factors: (i) the total or partial agonist character of the retinoid; (ii) the binding spectrum of the retinoid for the various types of retinoic acid receptors; (iii) the chemical and metabolic stability of the retinoid in the test system.

ISSN:0302-3427    

DOI:10.1159/000210878

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Glycyrrhizin (GL) is a saponin widely used as an anti-inflammatory agent. Pain intensity and HLA-DR antigen expression on CD8+ cells were assessed during and after treatment with GL. Other agents such as acyclovir,γ-globulin and interferon β were also administered for comparison. Pain resolved most rapidly among those treated with acyclovir followed by those treated with GL. Pain resolution correlated with the regression of HLA-DR+ in CD8+ subpopulations in peripheral blood. GL is suggested to be an alternative or additive antiviral agent to herpes zoste

ISSN:0302-3427    

DOI:10.1159/000210879

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0302-3427    

DOI:10.1159/000210880

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0302-3427    

DOI:10.1159/000210881

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0302-3427    

DOI:10.1159/000210882

出版商:S. Karger AG    

年代:1990

数据来源: Karger