| 1. |
- Barregård, Lars, 1948, et al.
(författare)
-
Human and Methodological Sources of Variability in the Measurement of Urinary 8-Oxo-7,8-dihydro-2 '-deoxyguanosine
- 2013
-
Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 18:18, s. 2377-2391
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: Urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to assay interference. Furthermore, optimal urine sampling conditions are not well defined. We performed inter-laboratory comparisons of 8-oxodG measurement between mass spectrometric-, electrochemical- and ELISA-based methods, using common within-technique calibrants to analyze 8-oxodG-spiked phosphate-buffered saline and urine samples. We also investigated human subject- and sample collection-related variables, as potential sources of variability. Results: Chromatographic assays showed high agreement across urines from different subjects, whereas ELISAs showed far more inter-laboratory variation and generally overestimated levels, compared to the chromatographic assays. Excretion rates in timed 'spot' samples showed strong correlations with 24 h excretion (the 'gold' standard) of urinary 8-oxodG (r(p) 0.67-0.90), although the associations were weaker for 8-oxodG adjusted for creatinine or specific gravity (SG). The within-individual excretion of 8-oxodG varied only moderately between days (CV 17% for 24 h excretion and 20% for first void, creatinine-corrected samples). Innovation: This is the first comprehensive study of both human and methodological factors influencing 8-oxodG measurement, providing key information for future studies with this important biomarker. Conclusion: ELISA variability is greater than chromatographic assay variability, and cannot determine absolute levels of 8-oxodG. Use of standardized calibrants greatly improves intra-technique agreement and, for the chromatographic assays, importantly allows integration of results for pooled analyses. If 24 h samples are not feasible, creatinine- or SG-adjusted first morning samples are recommended.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Ray, Jeremy, 1969, et al.
(författare)
-
Heritability of dental fear.
- 2010
-
Ingår i: Journal of dental research. - : SAGE Publications. - 1544-0591 .- 0022-0345. ; 89:3, s. 297-301
-
Tidskriftsartikel (refereegranskat)abstract
- The objective was to test a hypothesized genetic component (i.e., monozygotic being more similar compared with dizygotic twins) in dental fear/anxiety by comparing the probandwise concordance. We analyzed data based on a dichotomous measure of Dental Fear/Anxiety and a continuous measure of Dental Fear Intensity from over 2000 twins, collected when participants were 13-14 years old and once again three years later. The hypothesis was confirmed, but heritability of Dental Fear/Anxiety was estimated to be higher for girls (0.77 at time 1 and 0.55 at time 2) than for boys (0.14 and 0.0 at times 1 and 2, respectively). Heritability of Dental Fear Intensity, however, was similar for girls (0.30 and 0.40 at times 1 and 2, respectively) and boys (0.47, 0.44). Studies of the etiology of dental fear/anxiety should take genetic vulnerability into account and include molecular biology measures. Possible heritability differences between girls and boys need attention.
|
|
