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Wyszukujesz frazę "oxygen radicals" wg kryterium: Wszystkie pola


Wyświetlanie 1-7 z 7
Tytuł:
Reaktywne rodniki tlenowe - skuteczność antyoksydantów w terapii
Reactive oxygen radicals – the therapeutic effectiveness of antioxidants
Autorzy:
Skiba, M.
Pedrycz, A.
Cichacz, B.
Powiązania:
https://bibliotekanauki.pl/articles/366175.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Medycyny i Techniki Hiperbarycznej
Tematy:
oxidative stress
free radicals
antioxidants
stres oksydacyjny
wolne rodniki
antyoksydanty
Opis:
Oxidative stress occurring in cells is a consequence of an excessive activity of reactive oxygen forms, resulting from an imbalance between the release of free oxygen radicals and their removal from the cell by antioxidant systems. 90% of reactive oxygen radicals emerge in mitochondrial respiratory chain during an incomplete four-electron oxygen reduction. The remaining 10% originate from different reactions occurring in the cell. The established compounds are characterised by a short half-life and are highly reactive. Sparse quantities of free oxygen radicals have a positive effect on cell functions. Oxidative stress leads to damage in cellular membranes, enzymatic and non-enzymatic proteins, as well as DNA. Therapy with antioxidants as exogenous dietary supplements aims at preventing or reducing the risk of development of diseases involving the presence of the oxygen radicals. Whether the antioxidant therapy will bring positive or negative effects depends on numerous factors that need to be considered before their inclusion in the applied treatment.
Stres oksydacyjny w komórkach organizmu jest wynikiem nadmiernej aktywności reaktywnych form tlenu, wynikającym z zachwiania równowagi pomiędzy wydzielaniem wolnych rodników tlenowych, a ich usuwaniem z komórki przez systemy antyoksydacyjne. 90% reaktywnych rodników tlenowych powstaje w łańcuchu oddechowym mitochondrium, podczas niepełnej czteroelektronowej redukcji tlenu. Pozostałe 10% pochodzi z innych reakcje zachodzących w komórce. Związki które powstają mają krótki okres półtrwania i są wysoce reaktywne. Niewielkie ilości wolnych rodników tlenowych wpływają pozytywnie na funkcjonowanie komórek. Podczas stresu oksydacyjnego dochodzi do uszkodzenia błon komórkowych, białek enzymatycznych, nieenzymatycznych oraz DNA. Przyjmowanie antyoksydantów jako egzogennych suplementów diety ma na celu zapobieganie lub zmniejszenie ryzyka rozwoju chorób, w których patogenezie biorą udział rodniki tlenowe. To czy terapia z zastosowaniem antyoksydantów przynosi pozytywne czy negatywne efekty zależy od wielu czynników, które należy wziąć pod uwagę podczas włączania antyoksydantów do leczenia.
Źródło:
Polish Hyperbaric Research; 2016, 1(54); 41-48
1734-7009
2084-0535
Pojawia się w:
Polish Hyperbaric Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generowanie rodników tlenowych w procesie autooksydacji hemoprotein
Generation of oxygen radicals in the process of hemoprotein autoxidation
Autorzy:
Gondko, Roman
Gabryelak, Teresa
Chapman, Ian V
Powiązania:
https://bibliotekanauki.pl/articles/945009.pdf
Data publikacji:
1996
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Opis:
Life is a flux of matter, energy and information. Most compounds must remain in a reduced state in the stream. Living organisms use two sources of energy. Autotrophs utylise solar energy while heterotrophs make use of energy released from food oxidation. In the animated world, the turnover of matter is always accompanied by turnover of energy. Oxygen, which is an element indispensable for life of most organisms (aerobes), participates in these processes. In order to provide organisms with appropriate amounts of oxygen, appropriate adaptation mechanisms have evolved, enabling a continuous supply of this gas to cells. One mechanism is the vascular system, accompanied, at the molecular level, by the appearance of an oxygen-carrying respiratory proteins (e.g. hemoglobin, hemocyanin etc.).
Źródło:
Acta Universitatis Lodziensis. Folia Biochimica et Biophysica; 1996, 11
0208-614X
Pojawia się w:
Acta Universitatis Lodziensis. Folia Biochimica et Biophysica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metabolic activation of adriamycin by NADPH-cytochrome P450 reductase; overview of its biological and biochemical effects.
Autorzy:
Bartoszek, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/1043757.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
covalent binding to macromolecules
adriamycin
oxygen radicals
NADPH-cytochrome P450 reductase
Opis:
NADPH-cytochrome P450 reductase (P450 reductase) is one of the enzymes implicated in the metabolism of adriamycin, a very important clinically used antitumour drug. However, apart from the enzyme involvement, so far little was known about the chemical route and biochemical effects of this process. We demonstrated that the application of P450 reductase simultaneously with adriamycin to tumour cells in culture significantly increased cytotoxicity of the drug. Under tissue culture conditions, we noticed also that, in the presence of P450 reductase, adriamycin metabolite(s), displaying an altered spectrum within the visible light range were formed. This observation was taken adavantage of to study the metabolism of adriamycin in cell-free systems, using initially the enzyme isolated from rat liver and the recently obtained recombinant human P450 reductase. The reductive conversion of the drug turned out to be a multi-stage process, which occurred only under aerobic conditions and was accompanied by excessive NADPH consumption. Further research carried out with the aid of radical scavengers and radiolabelled adriamycin revealed that the enhancement of biological activity of adriamycin by P450 reductase stemmed from the formation of alkylating metabolite(s) rather than from the promotion of redox cycling known to be induced in the presence of anthracyclines.
Źródło:
Acta Biochimica Polonica; 2002, 49, 2; 323-331
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Arachidonic acid-induced apoptosis in rat hepatoma AS-30D cells is mediated by reactive oxygen species
Autorzy:
Dymkowska, Dorota
Wojtczak, Lech
Powiązania:
https://bibliotekanauki.pl/articles/1040493.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
antioxidants
apoptosis
arachidonic acid
hepatoma
oxygen free radicals
reactive oxygen species (ROS)
Opis:
Arachidonic acid at micromolar concentrations produced a drastic increase of the generation of reactive oxygen species (ROS) in rat hepatoma AS-30D cells cultivated in vitro along with an increase in the incidence of apoptotic cell death. Both processes were prevented by trolox, a water-soluble tocopherol derivative, and tempol, a known antioxidative agent. A synthetic hybrid of lipoic acid and trolox or preincubation with N-acetylcysteine were less effective. Preincubation of the cells with etomoxir, a known highly specific irreversible inhibitor of carnitine-palmitoyltransferase I, partly decreased the ROS formation induced by arachidonic acid but it did not affect the increase in apoptosis. Cumulatively, these results indicate that apoptosis induced in hepatoma cells by arachidonic acid is mediated by ROS. They also suggest that this effect is due to arachidonic acid as such and not to its mitochondrial oxidative metabolites.
Źródło:
Acta Biochimica Polonica; 2009, 56, 4; 711-715
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Protective role of L-methionine against free radical damage of rat brain synaptosomes
Autorzy:
Slyshenkov, Vyacheslav
Shevalye, Anna
Liopo, Anton
Wojtczak, Lech
Powiązania:
https://bibliotekanauki.pl/articles/1043695.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
(Na+,K+)-ATPase
oxygen free radicals
brain
synaptosomes
tert-butylhydroperoxide
L-methionine
Opis:
Incubation of rat brain synaptosomal/mitochondrial fraction with tert-butylhydroperoxide resulted in accumulation of the lipid peroxidation product, conjugated dienes, damage of the synaptosomal membrane as evidenced by leakage of lactate dehydrogenase, and decrease of the total content of glutathione and of the GSH/GSSG ratio. This treatment also produced a considerable decrease of the ouabain-sensitive ATPase activity and a much smaller diminution of the activities of glutathione reductase and glutathione transferase. Preincubation of the synaptosomal/mitochondrial fraction with 0.5 or 1.0 mM L-methionine significantly protected against lipid peroxidation, membrane damage and changes in the glutathione system produced by low (1 mM) concentrations of tert-butylhydroperoxide and completely prevented inactivation of ouabain-sensitive ATPase, glutathione reductase and glutathione transferase by such treatment. The importance of L-methionine in antioxidant protection is discussed.
Źródło:
Acta Biochimica Polonica; 2002, 49, 4; 907-916
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interactions of dietary carotenoids with singlet oxygen (1O2) and free radicals: potential effects for human health
Autorzy:
Böhm, Fritz
Edge, Ruth
Truscott, T
Powiązania:
https://bibliotekanauki.pl/articles/1039764.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
dietary carotenoids
singlet oxygen
free radicals
redox potentials
Opis:
The dietary carotenoids provide photoprotection to photosynthetic organisms, the eye and the skin. The protection mechanisms involve both quenching of singlet oxygen and of damaging free radicals. The mechanisms for singlet oxygen quenching and protection against free radicals are quite different - indeed, under some conditions, quenching of free radicals can lead to a switch from a beneficial anti-oxidant process to damaging pro-oxidative situation. Furthermore, while skin protection involves β-carotene or lycopene from a tomato-rich diet, protection of the macula involves the hydroxyl-carotenoids (xanthophylls) zeaxanthin and lutein. Time resolved studies of singlet oxygen and free radicals and their interaction with carotenoids via pulsed laser and fast electron spectroscopy (pulse radiolysis) and the possible involvement of amino acids are discussed and used to (1) speculate on the anti- and pro-oxidative mechanisms, (2) determine the most efficient singlet oxygen quencher and (3) demonstrate the benefits to photoprotection of the eye from the xanthophylls rather than from hydrocarbon carotenoids such as β-carotene.
Źródło:
Acta Biochimica Polonica; 2012, 59, 1; 27-30
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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