• MeSH
• DNA MeSH
• proteiny MeSH
• volné radikály MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biochemie
• biologie

Starnutie charakterizuje postupné zhoršovanie fyziologických funkcií a metabolických procesov. Bunkové a molekulové mechanizmy starnutia nie sú dosiaľ objasnené, rastie však počet experimentálnych dôkazov o úlohe oxidačného stresu v tomto procese. V tejto práci sme sledovali vplyv veku na 1) aktivity enzýmov α-ketoglutarátdehydrogenázy (KGDH) a cytochróm c oxidázy (COX) a 2) oxidačné modifikácie mitochondriálnych lipidov a bielkovín v mozgu potkanov kmeňa Wistar. Starnutie sprevádzal výrazný pokles aktivity oboch enzýmov, v mozgu 26mesačných zvierat bola aktivita KGHD znížená o 34,8 % a aktivita COX až o 52,2 % v porovnaní s aktivitou 5mesačných zvierat. Počas starnutia sa výrazne zvyšovala lipidová peroxidácia (LPO), koncentrácia produktov LPO v mitochondriách starých potkanov bola viac ako dvojnásobne zvýšená. Navyše, akumulácia týchto produktov viedla k štrukturálnej modifikácii mitochondriálnych bielkovín. Naše výsledky naznačujú, že jedným z pravdepodobných mechanizmov poklesu aktivity mitochondriálnych enzýmov počas starnutia je oxidačné poškodenie lipidov a bielkovín.

Aging is characterized by a progressive deterioration of physiological functions and metabolic processes. The exact cellular and molecular mechanizms of the aging process are unclear, but there is a growing evidence that age-related changes are consequences of oxidative stress. In the present study we examined the effect of aging on (i) α-ketoglutarate dehydrogenase (KGDH) and cytochrome c oxidase (COX) activity and (ii) oxidative modifications of mitochondrial lipids and proteins in brains from male Wistar rats. The activity of both enzymes was significantly reduced during aging, in hearts from 26-months-old rats KGDH and COX was lower by 34.8 ± 2.1% and 52.2 ± 1.1%, respectively, when compares to adult 5-months-old rats. Aging was associated with significant increase in lipid peroxidation (LPO), in old rats the concentration of LPO products increased more than 2 fold. Furthermore, the accumulation of LPO products leads structural modification of mitochondrial proteins. Our results suggest that loss of enzyme activities during aging may be related to oxidative modifications of mitochondrial proteins and/or lipids.

• MeSH
• finanční podpora výzkumu jako téma MeSH
• krysa rodu rattus MeSH
• mitochondriální proteiny analýza   MeSH
• mitochondrie enzymologie   metabolismus   MeSH
• modely u zvířat MeSH
• mozek cytologie   enzymologie   MeSH
• oxidační stres MeSH
• peroxidace lipidů MeSH
• stárnutí MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

Oxidační stres je důležitým faktorem v mnoha patologických i toxikologických procesech. Monitorovat oxidační stres lze pomocí produktů oxidačního poškození různých celulárních struktur, jako jsou produkty lipoperoxidace, DNA-hydroxylační produkty a hydroxylační produkty proteinů. 8-hydroxy- 2´-deoxyguanozin je hydroxylačním produktem poškození DNA, jeho hladinu lze stanovit v moči, popř. tkáních. Zatím nejcitlivější metodou pro stanovení tohoto biomarkeru je HPLC metoda s elektrochemickou detekcí.

Oxidative stress is an important factor in many pathological and toxicological processes. To follow-up the oxidative stress it is possible to determine the products resulting from free radical damage, these include : lipid peroxidation products, DNA-hydroxylation products and protein hydroxylation products. 8-hydroxy- 2´-deoxyguanosine is hydroxylation product of DNA damage. Its levels can be determined in urine or in tissues. The most sensitive method for the determination of 8-hydroxy-2´-deoxyguanosine is HPLC with electrochemical detection.

• MeSH
• biologické markery MeSH
• deoxyguanosin MeSH
• oxidační stres MeSH
• poškození DNA MeSH
• reaktivní formy kyslíku MeSH

• MeSH
• antioxidancia metabolismus   MeSH
• biologické markery MeSH
• glykosylace MeSH
• oxidační stres MeSH
• peroxidace lipidů MeSH
• volné radikály metabolismus   MeSH
• Publikační typ
• přehledy MeSH

HPLC determination of a background level of 8 oxodG and 2-dG in rat liver after addition of copper to perfusate was developed. The reversed phase analytical column Purospher® STAR C18e with 50 mmol L–1 phosphate buffer, pH 5.5 and methanol (92:8, v/v) mobile phase was applied for the analysis. The validation of the HPLC method according to linearity, accuracy and precision was carried out. Oxidative DNA damage (expressed as concentration ratio of 8-oxodG/106 2-dG) was determined by the simultaneous measuring of 2-dG with UV detection followed by coulochemical detection of 8 oxodG. The procedure using a model of liver damage caused by intoxication with copper and ischemia / reperfusion with addition of various concentrations of CuSO4 to the perfused rat livers was tested. The aim of this study was to decide whether the toxicity of copper in liver perfusates is related to protein oxidation and oxidative DNA damage. The high contribution to the DNA damage can be related to the physical liver manipulation during harvest and reperfusion as well as to artefacts induced during the sample preparation (time-consuming sample handling during DNA isolation and extraction). The obtained results pointed out that the DNA damage occurred already during liver handling even before application of CuSO4, whereby concentration of CuSO4 higher than 0.03 mmol L–1 caused a total liver damage, which led to a complete stop of the flow of the perfusate.

• MeSH
• biologické markery MeSH
• deoxyguanosin chemie   MeSH
• elektrochemické techniky * metody   využití   MeSH
• krysa rodu rattus MeSH
• měď * toxicita   MeSH
• nemoci jater * MeSH
• oxidační stres MeSH
• poškození DNA * MeSH
• spektrofotometrie metody   využití   MeSH
• vysokoúčinná kapalinová chromatografie * metody   využití   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

UNLABELLED: PURPOSE OF THE STUDY Ultrahigh molecular weight polyethylene (UHMWPE) is today the most frequently used bearing surface in total joint replacements (TJR) because of its properties, i.e., excellent biocompatibility, good mechanical and tribological performance and high wear resistance. UHMWPE liners are the most loaded TJR components and, therefore, their properties are decisive for TJR longevity. This study had three objectives: 1) to evaluate the oxidative degradation of explanted UHMWPE components; 2) to look for a statistically significant relationship between the extent of oxidative degradation and the durability of joint replacements; and 3) to investigate whether the durability of a TJR was related to the type of sterilisation used in manufacture. MATERIAL AND METHODS The study included 26 acetabular components obtained at revision arthroplasty between 2004 and 2013 from patients in whom a Beznoska/Poldi total hip replacement was used in the period from 1977 to 2002. The average age of the patients at the time of primary implantation was 57.9 years, the average longevity of the components removed was 18.63 years (range, 6.9 to 27.9 years). Samples of worn out and unworn areas from explanted components were processed in a three-step procedure in order to finally obtain 2-mm microtome sections. These were studied by infrared microspectroscopy. Oxidative damage to UHMWPE was determined as the oxidation index (OI); radiation damage to UHMWPE during sterilization was evaluated as the transvinylene index (VI); oxidation-induced changes in the polymer structure and its properties were characterised as the crystallinity index (CI); and local changes in mechanical properties due to oxidative degradation were assessed as microhardness (MH). Spearman's correlation coefficient and the Wilcoxon two-sample test were used for statistical analysis. RESULTS The OI values (average and maximum) in both worn out and unworn surface areas were related to component longevity. The difference between the oxidation index of ruptured components and that of the other components was statistically significant. Significant differences were also found between the average and maximum OI values of worn out areas and those of unworn surfaces. The relationship between the average oxidation index in both the unworn and worn out areas of UHMWPE components and the longevity of cracked components was statistically significant. DISCUSSION Our results show that the OI values obtained by microspectroscopy correlated with both the microscopic damage and the longevity of UHMWPE liners and the correlation was statistically significant also in relation to the longevity of total replacements. Relationships amongst OI, VI, CI and MH values as well as their relation to failure and longevity of total replacements are discussed. CONCLUSIONS It can be concluded that infrared microspectroscopic measurement of OI values is a simple and fast method to characterise UHMWPE liners. In addition, the IR spectra also show other supplementary characteristics, such as VI and CI indices. These values provide information on the quality of various UHMWPE types currently used in TJR surgery. The types of UHMWPE which exhibit high oxidative degradation should be avoided in clinical practice due to increased risk of early TJR failure. Responsible orthopedic surgeons should be aware of this fact and, if possible, collaborate with an independent, noncommercial laboratory in order to evaluate the quality of various UHMWPE liners used in their hospitals. KEY WORDS: UHMWPE, oxidation, total joint replacement, infrared spectroscopy, microhardness.

• MeSH
• biokompatibilní materiály chemie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• náhrada kyčelního kloubu přístrojové vybavení   MeSH
• oxidační stres fyziologie   MeSH
• polyethyleny chemie   MeSH
• reoperace MeSH
• selhání protézy MeSH
• senioři MeSH
• spektrofotometrie infračervená MeSH
• testování materiálů metody   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH

Sirtuiny, pojmenované podle jejich homologního proteinu „Silent Information Regulator Two“ pocházejícího z kvasinky Saccharomyces cerevisiae, představují skupinu vysoce mezidruhově konzervovaných nikotinamidadenindinukleotid dependentních enzymů, které deacetylují histony a odštěpují acetyl z lysinových reziduí proteinů. Hlavním cílem tohoto článku je stručně přiblížit farmakologický význam hlavních aktivátorů sirtuinu 1 přírodního nebo syntetického původu, které byly v průběhu posledních několika let testovány zejména při oxidativním poškození. V článku je především popsána související biologická aktivita těchto látek vzhledem k tomu, že jsou považovány za „favority“ při hledání nových farmakologicky aktivních látek a potenciálních léčiv. Díky nedávnému vývoji znalostí o vzájemné komunikaci mezi sirtuinem 1 a jeho modulátory (např. resveratrolem) získává farmakologický a klinický výzkum v této oblasti novou perspektivu.

Sirtuins, named after their homology to the Saccharomyces cerevisiae Silent Information Regulator Two, constitute a family of highly conserved nicotinamide adenine dinucleotide-dependent enzymes that deacetylate histones and residues of acetylated lysine. The main aim of this article is to put forward the pharmacological importance of major sirtuin 1 activators of natural or synthetic origin tested in last years in cases of oxidative tissue damage. The related bioactivity of these activators as “leading” compounds in the search for new drugs and remedies is also described. With the recent development of our knowledge on the cross talks between sirtuin 1 and its modulators (e.g. resveratrol), pharmacological and clinical research on this topic is getting a new horizon.

• Klíčová slova
• antioxidanty, metabolická onemocnění, nutraceutika, oxidativní stres, SIRT1 aktivátory,
• MeSH
• antioxidancia farmakologie   fyziologie   MeSH
• dlouhověkost MeSH
• kalorická restrikce MeSH
• lidé MeSH
• oxidační stres fyziologie   MeSH
• polyfenoly MeSH
• resveratrol MeSH
• sirtuin 1 fyziologie   MeSH
• sirtuiny MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

The potency of three nerve agents (sarin, soman, tabun) to induce oxidative damage of DNA in lymphocytes, liver and brain during lethal or sublethal poisoning was investigated. The single strand breaks or oxidative base DNA damage was evaluated with the help of Comet assay and a specific enzyme able to detect oxidative bases of DNA (endonuclease III). While sarin and soman administered at sublethal doses corresponding to 50% of their LD50 values were not able to induce oxidative damage of DNA, their lethal dose (LD50) induced the significant increase of the number of oxidative bases in DNA of hepatocytes. In addition, tabun administered at lethal dose (LD50) induced significant increase of the number of single strand breaks and oxidative bases of DNA in glial cells isolated from pontomedullar brain region. Thus, some nerve agents were able to induce oxidative damage in the peripheral as well as central compartment but only in the case of severe poisoning caused by lethal doses of nerve agents. This non-cholinergic effect of nerve agents has probably consequences with nerve agents-induced hypoxic status during acute cholinergic crisis and it can contribute to their long-term toxic effects.

• MeSH
• DNA * chemie   metabolismus   MeSH
• lidé MeSH
• organofosfáty toxicita   MeSH
• oxidační stres MeSH
• sarin toxicita   MeSH
• soman toxicita   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• antioxidancia MeSH
• glykosylace MeSH
• oxidační stres MeSH
• scavengery volných radikálů MeSH
• sulfonylmočovinové sloučeniny MeSH
• Publikační typ
• kongresy MeSH

• Konspekt
• Fyziologie člověka a srovnávací fyziologie
• NLK Obory
• vnitřní lékařství

Damage of molecules as a consequence of oxidative stress has been implicated in the pathogenesis of chronic diseases related to aging. Diet is a key environmental factor affecting the incidence of many chronic diseases. Antioxidant substances in diet enhance the DNA, lipid and protein protection by increasing the scavenging of free radicals. Products of oxidative damage of DNA (DNA strand breaks with oxidized purines or oxidized pyrimidines), lipids (conjugated dienes of fatty acids) and proteins (carbonyls) in relation to nutrition (vegetarian diet vs. non-vegetarian, traditional mixed diet) were measured in young women aged 20-30 years (46 vegetarians, 48 non-vegetarians) vs. older women aged 60-70 years (33 vegetarians, 34 nonvegetarians). In young subjects, no differences in values of oxidative damage as well as plasma values of antioxidative vitamins (C,ß-carotene) were observed between vegetarian and non-vegetarian groups. In older vegetarian group significantly reduced values of DNA breaks with oxidized purines, DNA breaks with oxidized pyrimidines and lipid peroxidation and on the other hand, significantly increased plasma values of vitamin C and ß- carotene were found compared to the respective non-vegetarian group. Significant age dependences of measured parameters (increase in all oxidative damage products and decrease in plasma vitamin concentrations in older women) were noted only in non-vegetarians. Vegetarian values of older women vs. young women were similar or non-significantly changed. The results suggest that increase of oxidative damage in aging may be prevented by vegetarian nutrition.

• Klíčová slova
• Oxidative damage, Nutrition, Antioxidative vitamins, Age,
• MeSH
• antioxidancia fyziologie   MeSH
• dieta vegetariánská MeSH
• dospělí MeSH
• financování organizované MeSH
• fyziologie výživy MeSH
• lidé středního věku MeSH
• lidé MeSH
• metabolismus lipidů fyziologie   MeSH
• oxidační stres fyziologie   MeSH
• poškození DNA MeSH
• proteiny metabolismus   MeSH
• senioři MeSH
• stárnutí fyziologie   MeSH
• vitaminy krev   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH