Rowett Research Institute

About: Rowett Research Institute is a based out in . It is known for research contribution in the topics: Rumen & Population. The organization has 2986 authors who have published 4459 publications receiving 239472 citations.

Oxidative stress in humans: validation of biomarkers of DNA damage

Abstract: Two studies have been performed to clarify the relationship between different markers of oxidative DNA damage commonly employed in molecular epidemiological studies. In the first, 8-Oxo-7,8-dihydroguanine (8-oxoGua) was induced in DNA of HeLa cells by treatment with different concentrations of photosensitizer Ro 19-8022 together with visible light. 8-OxoGua was estimated by the comet assay (alkaline single cell gel electrophoresis) with formamidopyrimidine DNA glycosylase and by HPLC with electrochemical detection. The dose-response curves indicate that the comet assay and HPLC are equally efficient at detecting induced damage. Background levels of 8-oxoGua in HeLa cells were 0.92 +/- 0.22 per 10(6) guanines by the comet assay and 2.09 +/- 0.13 per 10(6) guanines by HPLC. The second study was a small human trial, in which lymphocytes were collected for analysis of background levels of 8-oxoGua, as well as overnight and 24 h urine samples for measurement of excreted 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) by ELISA. The mean level of 8-oxoGua in lymphocytes was determined as 1.33 +/- 0.21 per 10(6) guanines by the comet assay and 3.72 +/- 1.06 per 10(6) guanines by HPLC. A strong correlation was seen between overnight and 24 h urinary 8-oxodGuo (r = 0.93, P < 0.01). Overnight urinary 8-oxodGuo concentrations correlated with 8-oxoGua in lymphocytes measured by HPLC (r = 0.85, P < 0.05) or by the comet assay (r = 0.86, P < 0.05), although individual values from HPLC and the comet assay did not correlate with each other. It is reasonable to assess oxidative stress by any of these methods.

Antioxidant intake and adult-onset wheeze: a case-control study

Abstract: An increase in prevalence of wheezing illness in the UK has coincided with a reduction in the consumption of natural antioxidants, which may modulate the lung's response to oxidant stress, limiting the expression of airway inflammation and respiratory symptoms. The hypothesis that intakes and plasma levels of natural anti- oxidants would be determinants of adult-onset wheezing illness was tested. A nested case-control study was conducted in 94 cases with adult-onset wheeze and 203 controls aged 39-45 yrs identified in a 30-yr follow-up survey. Antioxidant intake was measured by a food frequency questionnaire, and plasma and red cell measure- ments of antioxidant status were obtained. Outcome measures were onset of wheeze since age 15 yrs (ever wheeze) and wheeze occurring in the past 12 months (current wheeze). After adjusting for the effects of smoking, socioeconomic status, atopy, family his- tory of atopic disease and total energy intake, intakes of vitamin E (odds ratio (OR)=4.02 for low compared to high tertile of intake) and plasma levels of ascorbate (OR=0.98 per unit) and a-tocopherol:triglyceride ratio (OR=0.34 per loge unit) were inversely related to adult-onset wheeze. In analyses stratified by social class and smoking, intakes of vitamin C and E and plasma levels of ascorbate and a-tocophe- rol:triglyceride ratio were inversely related to current wheeze in the manual social class and among current smokers. No independent associations of vitamin A, b-caro- tene or total plasma antioxidant capacity were found. The results support the hypothesis that deficiencies of vitamins C and E are associ- ated with wheezing symptoms. Smokers in the manual social class are particularly susceptible to these effects. Eur Respir J 1999; 13: 22-30.

In vivo supplementation with coenzyme Q10 enhances the recovery of human lymphocytes from oxidative DNA damage

Abstract: SPECIFIC AIMSThis study was designed to investigate whether supplementation with CoQ10 protects DNA against oxidative damage in lymphocytes oxidized in vitro with compounds inducing different oxidizing profiles; DNA recovery from oxidative damage was also studied. The hypothesis that CoQ10 supplementation might modulate the repair enzyme activity will be tested on whole cell extract lymphocytes.PRINCIPAL FINDINGS1. Coenzyme Q10 in vitro enrichment inhibits the formation of DNA strand breaks induced by atmospheric oxygenThe incubation of lymphocytes under atmospheric oxygen leads to a formation of DNA strand breaks (SBs) detectable within the first hour of exposure. Both ubiquinol-10 and ubiquinone-10 are able to prevent DNA SB formation, the enriched lymphocytes resulting in less damage and exhibiting a faster DNA repair rate than that of nonenriched control lymphocytes (Fig. 1a⤻ ). Conversely, the ubiquinol-10 or ubiquinone-10 neither prevents the endogenous formation of oxidized purine and pyrimidine ba...

Kinetic and Stoichiometric Assessment of the Antioxidant Activity of Flavonoids by Electron Spin Resonance Spectroscopy

Abstract: There is current interest in the use of naturally occurring flavonoids as antioxidants for the preservation of foods and the prevention of diseases such as atherosclerosis and cancers. To establish the molecular characteristics required for maximum antioxidant activity, electron spin resonance (ESR) spectroscopy has been used to determine the stoichiometry and kinetics of the hydrogen-donating ability of 15 flavonoids and d-alpha-tocopherol to galvinoxyl, a resonance-stabilized, sterically protected aryloxyl radical. The second-order reaction rates, which will be governed by O-H bond dissociation energies, were myricetin > morin > quercetin > fisetin approximately catechin > kaempferol approximately luteolin > rutin > d-alpha-tocopherol > taxifolin > tamarixetin > myricetin 3',4',5'-trimethyl ether > datiscetin > galangin > hesperitin approximately apigenin. Reactivity is highly dependant on the configuration of OH groups on the flavonoid B and C rings, there being little contribution from the A ring to antioxidant effectiveness. Highest reaction rates and stoichiometries were observed with flavonols capable of being oxidized to orthoquinones or extended paraquinones. However, rates and stoichiometries did not always correlate and the data suggest that kinetic factors may be of greater importance within a biological context.