Nanomaterials represent a promising novel class of materials to be used as antibacterial solutions. Inhomogeneity of synthesis and characterization methods, as well as resulting variate physical and chemical properties make selection of proper nanostructure difficult when designing antimicrobial experiments. Present study focuses on the already existing evidence regarding silver nanoparticles and their antibacterial applications, with focus on various modulatory factors of reported antimicrobial efficiency. Present paper focuses on synthesis and characterization methods, factors modulating antibacterial efficiency, laboratory quantification procedures, as well as up–to-date knowledge on mechanisms of antibacterial action for silver nanoparticles. Moreover, challenges and future prospects for antimicrobial applications of silver nanoparticles are reviewed and discussed.
Psoriasis vulgaris, a chronic inflammatory skin disorder, is the result of immune mediated processes, genetic background and environmental factors. Prolactin and the vascular endothelial growth factor seem to play a key role in psoriasis pathogenesis regarding hyperproliferation of epidermal keratinocytes and dermal vascular ectasia. The aim of the study was to investigate the expression of tumor necrosis factor-α (TNF-α), vascular endothelial growth factor receptor 2 (VEGFR2) and prolactin receptor (PRLR) in psoriatic skin by immunohistochemical analysis and to evaluate the correlation with disease severity. Two skin biopsies, psoriatic lesion and perilesional skin, obtained by punch biopsy from 19 nontreated psoriasis patients were examined in hematoxylin and eosin staining and immunohistochemistry (IHC) for TNF-α, VEGFR2 and PRLR. The indirect IHC reaction was carried out automatically and visualized by 3,3-diaminobenzidine (DAB) technique. The average number of DAB-positive cells and the intensity of cell staining were quantified on a predefined scale. The results show a significant difference in the quantity and distribution of TNF-α positive cells in the two sample groups. In psoriatic plaque skin, an increased expression of TNF-α was found in the perivascular dermis and epidermic keratinocytes. In perilesional skin the immunostaining was predominant in the basal layer keratinocytes, while in psoriatic plaque, all the layers were positively marked, with stronger expression at the base. A statistically significant difference was found between the intensity of the immunostaining in the two types of tissue. Positive cells for VEGFR2 and PRL were identified in the basal layer keratinocyte cells (VEGFR2), sweat glands and hair outer shaft sheath (PRLR), without significant differences between the two types of samples. Our findings confirm the importance of TNF-α in psoriasis pathogenesis and a positive correlation with lesions severity. No significant differences were found for VEGFR2 and PRLR, but additional studies are necessary to establish their role.
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