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Serum immunoglobulins were determined in 40 Egyptian patients with schistosomiasis. In addition to the well-established elevation in total IgE, a striking imbalance in the IgG subclass levels was found: IgG3 and IgG4 levels were markedly elevated, whereas IgG2 levels were normal. The IgG4 level did not correlate with the IgG3 level, but a weak correlation between the IgG4 levels and the logarithmic value of the IgE levels was observed (r = 0.49). We determined anti-schistosome antibodies in the IgE and IgG classes and in the IgG4 subclass by a RAST-type of assay. As test antigens an adult worm antigen preparation (AWA) and a soluble egg antigen preparation (SEA) were used. IgE antibodies reacted predominantly with AWA, whereas IgG4 antibodies, especially in patients with recent infections, were directed mainly against SEA. The hypothesis is put forward that the IgG4 antibodies interfere with the effector activities of anti-schistosome anibodies, and thus inhibit complement activation and mast cell triggering.

Availability of a standard human melanocyte cell line with unlimited growth potential and otherwise normal melanocytic properties will greatly facilitate research in melanocyte biology and in vitro studies on the etiology of pigmentary disorders and melanoma. Using a retroviral vector, E6 and E7 open reading frames of human papilloma virus type 16 (HPV 16) have been introduced into cultured normal human melanocytes. Cells selected by increased resistance to geneticin conveyed by the vector and expressing E6E7 mRNA have been cloned to ensure genetic homogeneity. Since their establishment as primary cells, cloned PIG1 cells have undergone more than twice the amount of population doublings of senescent parental cells. Moreover, in passage numbers when parental cells had become senescent, proliferation of clonal cells was retained at levels exceeding those of normal human melanocytes in third passage by 100%. Further characterization has revealed that the cells remain dependent on tetradecanoyl phorbol 13-acetate (TPA) for growth and do not proliferate in soft agar nor form tumors in nude mice. The antigenic profile of the cells was slightly altered as compared to parental cells, but was incomparable to that of M14 melanoma cells. Importantly, PIG1 cells contain more melanin pigment than parental cells.

Smaller sheaths, radial access, and timely sheath removal may mitigate the bleeding risk associated with potent antithrombotic/platelet therapy and early catheterization.

The aim of the present study was to explore whether nitric oxide (NO) interferes with the attachment of human melanocytes to the extracellular matrix (ECM) components. Consequently, the effects have been investigated of the NO‐releasing compounds 3‐morpholino‐sydnonimine (SIN‐1) and S‐nitroso‐glutathione (GSNO) on the in vitro adhesion of human melanocytic cells to fibronectin. The NO donors induced a concentration‐dependent reduction in the adhesion of both 51CrO42−‐labelled melanocytes and melanoma cells to fibronectin. Pigmented M14 melanoma cells were more susceptible to the effect of SIN‐1 (half‐maximal inhibiting effect at about 0·5 mm) than normal human melanocytes and also than the non‐pigmented melanoma cells Mel57 (half‐maximal inhibiting effects between 0·9 and 2 mm). This effect of SIN‐1 also appeared to be related to the melanin content of normal melanocytes, whereas GSNO was significantly less active. Both flow cytometric analysis and immunocytochemical staining showed expression of neuronal NO synthase in all cell lines. The results of this study suggest that aberrant in vivo production of NO during infection and inflammation may contribute to loss of melanocytes in, for example, vitiligo, by reducing de novo attachment of melanocytes to the ECM. These findings could also be important for understanding the process of metastasis. © 1997 John Wiley & Sons, Ltd.

BACKGROUND:Currently, the cosmetic industry is overwhelmed in keeping up with the safety assessment of the increasing number of new products entering the market. To meet such demand, research centers have explored alternative methods to animal testing and also the large number of volunteers necessary for preclinical and clinical tests.OBJECTIVES:This work describes the human skin ex-vivo model (hOSEC: Human Organotypic Skin Explant Culture) as an alternative to test the effectiveness of cosmetics and demonstrate its viability through cutaneous keratinocytes' proliferative capacity up to 75 days in culture.METHODS:The skin explants obtained from surgeries were cultured in CO2-humid incubator. After 1, 7, 30 and 75 days in culture, skin fragments were harvested for analysis with histomorphological exam (HE staining) on all days of follow-up and immunohistochemistry for Ck5/6, Ck10 and Ki-67 only on the 75th day.RESULTS:On the 7th day, the epidermis was perfect in the dermoepidermal junction, showing the viability of the model. On the 30th day, the epidermis was thicker, with fewer layers on the stratum corneum, although the cutaneous structure was unaltered. On the 75th day, the skin became thinner but the dermoepidermal junctions were preserved and epidermal proliferation was maintained. After the 75th day on culture, the skin was similar to normal skin, expressing keratinocytes with Ck5/6 on supra-basal layers; Ck10 on differentiated layers; and viability could be assessed by the positivity of basal cells by Ki-67.CONCLUSION:The hOSEC model seems a good alternative to animal testing; it can be used as a preclinical test analogous to clinical human skin test with similar effectiveness and viability proven by immunohistological analyses.