Oliver Schnorr

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BACKGROUND Oxidative damage of vascular endothelium represents an important initiation step in the development of atherosclerosis. Recently, we reported about protection of inducible nitric oxide synthase (iNOS)-derived high-output NO in endothelial cells. Because iNOS activity critically depends on the availability of its substrate l-arginine, the present(More)
The availability of l-arginine can be a rate-limiting factor for cellular NO production by nitric oxide synthases (NOS). Arginase competes with NOS for l-arginine as the common substrate. Increased arginase activity has been linked to low NO levels, and an inhibition of arginase activity has been reported to improve endothelium-dependent vasorelaxation.(More)
Regulated uptake of extracellular l-arginine by cationic amino acid transporters (CATs) is required for inducible nitric oxide synthase and arginase activity. Both enzymes were recently recognized as important in the pathophysiology of psoriasis because of their contribution to epidermal hyperproliferation. We here characterize the expression pattern of(More)
Nitrite occurs ubiquitously in biological fluids such as blood and sweat, representing an oxidation product of nitric oxide. Nitrite has been associated with a variety of adverse effects such as mutagenicity, carcinogenesis, and toxicity. In contrast, here we demonstrate that the presence of nitrite, but not nitrate, during irradiation of endothelial cells(More)
Abnormal proliferation of keratinocytes in the skin appears crucial to the pathogenesis of psoriasis, but the underlying mechanisms remain unknown. Nitric oxide (NO), released from keratinocytes at high concentrations, is considered a key inhibitor of cellular proliferation and inducer of differentiation in vitro. Although high-output NO synthesis is(More)
The expression of the inducible nitric oxide synthase (iNOS) is one of the direct consequences of an inflammatory process. Early studies have focused on the potential toxicity of the ensuing high-output NO-synthesis serving as a means to eliminate pathogens or tumor cells but also contributing to local tissue destruction during chronic inflammation. More(More)
Nitric oxide (NO) plays a pivotal role in ultraviolet radiation-induced inflammation in human skin. We had earlier reported on the inducible nitric oxide synthase (iNOS) inducing activity of UVA radiation. We now demonstrate that UVB-exposure induces expression of the iNOS in vessel endothelia of normal human skin and in cultured human dermal endothelial(More)
Inducible nitric oxide synthase and arginase activities are acknowledged as important players in human skin epidermal function. For proper enzyme function the substrate availability of L-arginine for both enzymes and thus its transport across the cell membrane via the y+-system (also named cationic amino acid transporters) is critical. Here, we examine the(More)
Cytokines represent an integral part of the large group of mediators involved in dermal inflammation. In this in vivo study, ultraviolet light which is one of the major environmental factors affecting cytokine release patterns in the skin was employed. The effects of repeated versus one-time irradiation with solar-simulated ultraviolet light was studied(More)
The impact of nutrients on gene expression can be mediated by the availability of amino acids. The aim of this study is to examine the effect of limited availability of l-arginine on the DNA-binding activity of NF-κB, a dominant transcription factor in inflammation, and the consequence for the expression pattern of inducible nitric oxide synthase (iNOS) in(More)