Nitric oxide (NO) is related to a wide range of physiological processes such as vasodilation, macrophages cytotoxicity and wound healing. The human skin contains NO precursors (NO x). Those are mainly composed of nitrite (NO 2 −), nitrate (NO 3 −), and S-nitrosothiols (RSNOs) which forms a large NO store. These NO x stores in human skin can mobilize NO to blood stream upon ultraviolet (UV) light exposure. The main purpose of this study was to evaluate the most effective UV light wavelength to generate NO and compare it to each NO precursor in aqueous solution. In addition, the UV light might change the RSNO content on human skin. First, we irradiated pure aqueous solutions of NO 2 − and NO 3 − and mixtures of NO 2 − and glutathione and NO 3 − and S-nitrosoglutathione (GSNO) to identify the NO release profile from those species alone. In sequence, we evaluated the NO generation profile on human skin slices. Human skin was acquired from redundant plastic surgical samples and the NO and RSNO measurements were performed using a selective NO electrochemical sensor. The data showed that UV light could trigger the NO generation in skin with a peak at 280-285 nm (UVB range). We also observed a significant RSNO formation in irradiated human skin, with a peak at 320 nm (UV region) and at 700 nm (visible region). Pre-treatment of the human skin slice using NO 2 − and thiol (RSHs) scavengers confirmed the important role of these molecules in RSNO formation. These findings have important implications for clinical trials with potential for new therapies.
Nitric oxide (NO) is a crucial molecule in the human body. The encapsulation of exogenous NO donors into chitosan nanoparticles (CS NPs) has been widely used to overcome NO drawbacks in pharmacological applications, such as, its short half-life. The NO donor, S-nitrosoglutathione (GSNO), was encapsulated into CS NPs (GSNO-CS NPs) and characterized by AFM and DLS measurements. The nanoparticles presented a hydrodynamic size of 123.3 ± 1.5 nm and a polydispersity of 0.25 ± 0.01. The ability of GSNO-CS NPs, combined with UV irradiation, to deliver NO was evaluated using ex vivo human skin. The human skin was pre-treated with GSNO-CS NPs, in the presence and absence of UV irradiation. The results showed that the combined treatment significantly increased the NO and S-nitrosothiol levels in human skin. This effect can emulate the cardiovascular benefits related to NO without negative side effects of skin exposure to UV light.
The characteristics of the Cu-18.84 at.%Al-10.28 at.%Mn-1.57 at.%Ag alloy after slow cooling from high temperatures were studied using optical and scanning electron microscopies, microhardness measurements with temperature, differential scanning calorimetry, X-ray diffraction, magnetic moment changes with temperature and applied field. The results indicated the presence of a new transition associated with dissolution of the Ag-rich phase. It was also verified that the content of Al strongly interferes with the magnetization of the Cu-18.84 at.%Al-10.28 at.%Mn-1.57 at.%Ag alloy, since at lower Al concentration the relative fraction of the ferromagnetic L2 1-(Cu 2 AlMn) phase is decreased.
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