Biomedical subjects

E H M Temme

Publications and source records attributed to E H M Temme.

3 recordsLinked to original sources

PubMed2004

Does vitamin C supplementation influence the levels of circulating oxidized LDL, sICAM-1, sVCAM-1 and vWF-antigen in healthy male smokers?

OBJECTIVE: To examine the effects of vitamin C supplementation on the concentration of oxidation markers, in particular, circulating oxidized LDL (OxLDL) and on endothelial activation markers. DESIGN: Randomized double-blind, placebo-controlled crossover trial. SETTING: Belgian population of the city of Leuven. SUBJECTS: A total of 34 healthy male smokers aged 26-73 y. INTERVENTION: Smokers were randomly assigned to receive either vitamin C (250 mg twice daily) or placebo capsules, each to be taken for 4 weeks. After a 1-week washout period, participants then crossed over to the alternative capsules for further 4 weeks. MEAN OUTCOME MEASURES: Markers of oxidation (bilirubin, uric acid, alpha-tocopherol, retinol, malondialdehyde, circulating Oxidized LDL (OxLDL)) and markers of endothelial activation (sICAM-1, sVCAM-1, vWF-antigen) were analysed. RESULTS: Plasma ascorbate concentrations significantly increased from 46.6+/-17.6 to 70.1+/-21.2 mumol/l after a 4-week treatment with 500 mg vitamin C per day. The other plasma antioxidants concentrations, including bilirubin, uric acid, alpha-tocopherol and retinol, were similar in both treatment periods. Vitamin C did not change plasma malondialdehyde and circulating OxLDL compared with placebo (vitamin C 0.73+/-0.25 mg/dl OxLDL; placebo 0.72+/-0.21 mg/dl OxLDL). After vitamin C supplementation, neither sICAM-1 and sVCAM-1 levels nor the concentration of vWF-antigen significantly differed from placebo condition. CONCLUSIONS: Oral supplementation of vitamin C is not associated with changes in markers of oxidation or endothelial activation in healthy male smokers.

Adult↗

PubMed2004

Quantitative analysis of 8-isoprostane and hydrogen peroxide in exhaled breath condensate.

Exhaled breath condensate (EBC) provides a noninvasive means of sampling the lower respiratory tract. Collection of EBC might be useful in the assessment of airway oxidative stress in smokers. The aim of this study was to determine 8-isoprostane and hydrogen peroxide levels in EBC, and, in addition, to investigate the reproducibility of these measurements. EBC samples were collected from 12 healthy male smokers at three time points within 1 week. 8-isoprostane and H2O2 were measured in nonconcentrated EBC using immunochemical and colorimetric assays, respectively. 8-isoprostane and H2O2 were detected in only 36 and 47% of all EBC samples, respectively. It was not possible to calculate the within-subject variation in a reliable manner since only three of the 12 smokers exhibited detectable 8-isoprostane concentrations on all three occasions (mean 4.6 pg x mL(-1); range 3.9-7.7 pg x mL(-1)), whereas H2O2 could not be detected on all three occasions in any of the smokers. Spiking experiments revealed a recovery of 83.5-109.5% for 8-isoprostane and 69.9-129.0%, for H2O2 in fresh EBC samples. It was concluded that levels of 8-isoprostane and hydrogen peroxide cannot be reproducibly assessed in exhaled breath condensate from healthy smokers because of their low concentration and/or the lack of sensitivity of the available assays.

Adult↗

PubMed2002

Tea consumption and iron status.

OBJECTIVE: To give an overview of the association between tea consumption and iron status. METHODS: A PUBMED search was performed (up to June 2001) for all publications containing the words: tea and ferritin, h(a)emoglobin, iron status or an(a)emia. Sixteen studies were evaluated in groups with high (infants, children and premenopausal women) or low prevalence of iron deficiency (men and the elderly). RESULTS AND DISCUSSION: Of the 16 studies reviewed, six included infants and children, six premenopausal women, two men and two the elderly. In study groups with high prevalence of iron deficiency, tea consumption was inversely associated with serum ferritin and/or haemoglobin. The association disappeared when adjusting for confounding (dietary) factors, except for one study including 40% of iron deficient women. In groups with low prevalence of iron deficiency, tea consumption was not inversely associated with serum ferritin and/or haemoglobin. In those at risk for iron overload, such as middle-aged men, tea consumption may lower serum ferritin concentrations as reported in one study. This finding awaits further confirmation. CONCLUSION: This overview shows that tea consumption does not influence iron status in Western populations in which most people have adequate iron stores as determined by serum ferritin concentrations. Only in populations of individuals with marginal iron status does there seem to be a negative association between tea consumption and iron status.

Adolescent↗