In vivo evaluation of a Poly-2p barrier cream protective effect.

AIM: Theoretically, skin barrier creams reduce or even prevent the penetration into the skin by building up a physical barrier, like a thin film between the skin and the irritant. Practically, controversial experiences concerning the effectiveness of barrier creams exist. For this, we propose an in vivo method to evaluate the efficacy of barrier creams trough clinical scoring and instrumental analysis. METHODS: Nineteen housewives with hand dermatitis in remission phase were enrolled in the study. Every patient was evaluated clinically and an arbitrary score was assigned by the investigator considering erythema, exudation, lichenification and xerosis. A score was also assigned by every patient to itching and burning. As measurement of the functional state of the skin and of the effectiveness of the barrier cream, transepidermal water loss (TEWL), corneometry, colorimetry and visco-elasticity determination were performed. To investigate the protection properties against irritant products, the 24-h irritancy patch test with sodium lauryl sulphate 1% in water was used. RESULTS: Through the patch test technique the efficacy of the barrier cream was tested compared to other topical products containing corticosteroids, lipids, humectants or urea, with already known anti-inflammatory, lenitive or protective properties. The results showed this methods easy and fast in handling, non-invasive, standardized, and in vivo applicable for evaluation and ranking of barrier creams. CONCLUSION: The study preparation demonstrated high tolerability and indubitable efficacy in improving the skin barrier function even towards a very well known irritant.

Induction of megakaryocytic characteristics in human leukemic cell line K562: polyploidy, inducers, and secretion of mitogenic activity.

Because of the rarity of megakaryocytes in the bone marrow, a cell line inducible for megakaryocytic characteristics provides a valuable model for study. When cultured with phorbol esters, the human multipotent hematopoietic leukemic cell line K562 can be induced to develop many megakaryocytic characteristics, viz. increased cell size, reduced growth rate, megakaryocytic antigens, and expression of the sis proto-oncogene, the structural gene for the B-chain of platelet-derived growth factor. Further aspects of this process are here presented. First, it induces the release of mitogenic activity into the medium. Second, phorbol dibutyrate induces polyploidy, a feature of normal megakaryocyte development. Third, mezerein and teleocidin, nonphorbol ester tumor promotors, also induce development of multinuclearity and polyploidy.

K562 human erythroleukemia cell variants resistant to growth inhibition by butyrate have deficient histone acetylation.

K562 is an established human erythroleukemia cell line, inducible for hemoglobin synthesis by a variety of compounds including n-butyrate. To elucidate the role of butyrate-induced histone acetylation in the regulation of gene expression in K562 cells, we isolated 20 variants resistant to the growth inhibitory effect of butyrate. Four variants having different degrees of resistance were selected for detailed study. All four were found to be resistant to the hemoglobin-inducing effect of butyrate, suggesting that the two aspects of butyrate response, restriction of growth and induction of hemoglobin synthesis, are coupled. Further, after (5 days) culture with butyrate, two of the four variants exhibit less acetylation of H3 and H4 histones than does the butyrate-treated parent. Analysis of histone deacetylases from the variants indicated that each variant was distinct and that butyrate resistance may be accounted for by decreased affinity of the variant enzymes for butyrate, increased affinity of the enzymes for acetylated histone, or both. The fact that variants selected for resistance to growth inhibition by butyrate are also deficient in butyrate-induced hemoglobin synthesis and have abnormal histone deacetylase activity argues for butyrate inducing K562 cells to synthesize hemoglobin and restrict growth via histone acetylation.