title: [Reactive nitrogen and oxygen species].
abstract: Reactive nitrogen species (RNS) and reactive oxygen species (ROS) are mainly free radicals which including non-paired electrons. They are constantly formed as side products of biological reactions. They are also generated directly and indirectly by the cells which were exposed to environmental stress, i.e., UV radiation, ionizing radiation, xenobioticts, light-absorbing compounds, e.g., porphyrines. These factors, which are a source of free radicals, initiate a significant signaling cascade inducing many changes in cells, such as cancerogenic transformation or cell death. Cells protect themselves against oxidative stress by means of antioxidative enzymes and compounds which in their structure have redox sensitive spots.
authors.affiliation: Wyzsza Szkola Kosmetologii i Ochrony Zdrowia w Białymstoku, Zakład Nauk Chemicznych.
authors.forename: Helena
authors.initials: H
authors.lastname: Puzanowska-Tarasiewicz
authors.forename: Ludmiła
authors.initials: L
authors.lastname: Kuźmicka
authors.forename: Mirosław
authors.initials: M
authors.lastname: Tarasiewicz
mesh_terms: D000818:Animals; D016923:Cell Death / Q000502:physiology; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D006801:Humans; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species