PubMed · 7924445
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C G Webster, J W Burnett. 1994. Gold dermatitis.. https://pubmed.ncbi.nlm.nih.gov/7924445/
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The objective of this work is to investigate the percutaneous permeability of 2,3,5,6-tetramethylpyrazine (TMP), an active ingredient originally isolated from Ligusticum wallichii Franch. Certain physicochemical properties of TMP, including its partition coefficient and pH-solubility profile, were studied. The influence of pH on the percutaneous permeation of TMP was studied in vitro using hairless mouse skin. Comparative in vitro permeability of TMP through hairless mouse, rat, rabbit, and human cadaver skin was also investigated. The results indicate that hairless mouse skin and rat skin were about three to four times more permeable to TMP than human cadaver skin. The permeability of TMP through rabbit skin was not significantly different from that of human cadaver skin. The observed lag times for all skin membranes were about 1-2h. Although pharmacokinetic data are not currently available to permit precise calculation of a clinically effective patch size, the data from this study indicate that the transdermal delivery of TMP should nevertheless be possible.
Th2 responses are clearly involved in the pathogenesis of atopic disease. Thus, understanding the factors responsible for Th2 sensitization at sites of allergen exposure, such as airway and skin, is crucial for directing therapeutic or preventive strategies. Contrary to other models of Th2 sensitization to proteins, we have reported that Th2 responses induced by epicutaneous exposure to OVA are IL-4 independent. Combined deficiency of both IL-4 and IL-13 signaling did prevent Th2 generation, suggesting that IL-13 was mediating these IL-4-independent responses. It was not clear, however, whether IL-13 was simply replacing the need for IL-4 in genetically deficient mice or if IL-13 played a unique role. In the present study, we show that Th2 responses induced by epicutaneous OVA exposure (including lung inflammatory responses after inhaled Ag challenge, OVA-specific IgG1, and draining lymph node IL-5 production) are impaired in IL-13-deficient (IL-13(-/-)) mice compared with wild type. In contrast, i.p. sensitization of IL-13(-/-) mice resulted in responses equivalent to wild type. Generation of contact hypersensitivity to dinitrofluorobenzene, which involves Th1 and CD8(+) effector cells, was also intact in IL-13(-/-) mice. Taken together, the data indicate that IL-13 is the major inducer of Th2 generation in the cutaneous microenvironment, being required independently of IL-4. This fact, in combination with the known abundance of IL-13 in atopic dermatitis skin lesions, emphasizes the potentially important role of the skin as a site for Th2 sensitization to environmental allergens, particularly in atopic individuals.
OBJECTIVE: To evaluate whether in healthy postmenopausal women endothelial substances such as endothelin-1 (ET-1) and nitric oxide are related to cardiovascular risk factors and can be influenced by estradiol replacement. DESIGN: A cross-sectional evaluation and a randomized, double-blind, placebo-controlled study with cross-over. METHODS: In 20 healthy postmenopausal women it was investigated the relation of ET-1 and NOx with age, BMI, 24-h blood pressure, lipid and glucose metabolism, and coagulation parameters. In addition, in the same women, the role played by estrogens on circulating ET-1 and stable derivatives of nitric oxide (nitrite/nitrates) was investigated by administering for 2 months transdermal estradiol (50 microg/day) vs. placebo. RESULTS: ET-1 and NOx were inversely related to each other (r=0.458; P=0.016). Multivariate analysis of regression showed that ET-1 levels were related directly to LDL-cholesterol (r=0.585; P=0.0005) and protein C (r=0.516; P=0.0008), and inversely to insulin (r=0.488; P=0.0065). The ratio NOx/ET-1 was directly related to HDL-cholesterol (r=0.441; P=0.005). The above relations were not influenced by estradiol. Indeed, in comparison to placebo, transdermal estradiol, besides reducing nocturnal systolic (P=0.002) and diastolic (P=0.03) blood pressure, did not modify ET-1 or NOx levels, as well as, any of the parameters considered. CONCLUSIONS: The relation of several cardiovascular risk factors with ET-1 and NOx/ET-1 suggests a primary role for these endothelial products in the determination of the cardiovascular risk of women. The present data do not support a role for transdermal estradiol in modifying ET-1 or NOx levels of healthy postmenopausal women.