https://febs.onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793%2897%2900469-9

What nitrates tyrosine? Is nitrotyrosine specific as a biomarker of peroxynitrite formation in vivo?

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Oxidative damage of DNA caused by a variety of chemical and physical agents appears to be linked to cancer. However, it is becoming increasingly clear that endogenous generation of oxidants, such as hydroxyl radical and peroxynitrite, lead to oxidation of DNA, and this may cause cancer in individuals where no obvious exposure to chemical or physical agents known to be carcinogenic has occurred. The mechanisms for generation of these two oxidants in living organisms will be discussed and their reactivities with DNA to produce oxidized products (e.g., 8-oxo-dG) will be presented with special emphasis on the individual characteristics of the generation and reactivity of each oxidant.

/pdf/mechanisms-of-dna-oxidation-5fk9aak982.pdf

Mechanisms of DNA oxidation.

1. Peroxynitrite is a short-lived and damaging oxidant that forms rapidly from the reaction of superoxide with nitric oxide. 2. In 1990, Joseph Beckman proposed that peroxynitrite contributed significantly to pathological oxidative stress in living tissues, and subsequent evidence strongly supports this proposal. 3. In this review, we outline the properties of peroxynitrite and discuss how it can affect biological systems and contribute to human pathologies.

Peroxynitrite: a biologically significant oxidant.

OBJECTIVES: This study was carried out to investigate the potential of titanium to induce hypersensitivity in patients chronically exposed to titanium-based dental or endoprosthetic implants. METHODS: Fifty-six patients who had developed clinical symptoms after receiving titanium-based implants were tested in the optimized lymphocyte transforma tion test MELISA® against 10 metals including titanium. Out of 56 patients, 54 were patch-tested with titanium as well as with other metals. The implants were removed in 54 patients (2 declined explantation), and 15 patients were retested in MELISA®. RESULTS: Of the 56 patients tested in MELISA®, 21 (37.5%) were positive, 16 (28.6%) ambiguous, and 19 (33.9%) negative to titanium. In the latter group, 11 (57.9%) showed lymphocyte reactivity to other metals, including nickel. All 54 patch-tested patients were negative to titanium. Following removal of the implants, all 54 patients showed remarkable clinical improvement. In the 15 retested patients, this clinical improvement correlated with normalization in MELISA® reactivity. CONCLUSION: These data clearly demonstrate that titanium can induce clinicallyrelevant hypersensitivity in a subgroup of patients chronically exposed via dental or endoprosthetic implants.

/pdf/hypersensitivity-to-titanium-clinical-and-laboratory-1px8el72d7.pdf

J.S. Beckman

Papers

Detection of Peroxynitrite