Biorepositories - At the bleeding edge

International Journal of Epidemiology (Impact Factor: 9.18). 05/2008; 37(2):231-3. DOI: 10.1093/ije/dym282
Source: PubMed
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    ABSTRACT: Today's biobanks must work to take full advantage of collected samples, while maximizing sample quality and minimizing costs to sustain operations for a long period of time. This is a tall order that will require collaboration and compromise for both end-users and collection sites. This article discusses the efforts of the Génome Québec-Centre Hospitalier Affilié Universitaire Régional de Chicoutimi Biobank to fractionate blood samples for the simultaneous preservation of plasma and DNA-containing layers while minimizing resources required for shipping and transport. This article also describes methods for successful reproducible application of the plasma-depleted blood sample to GenPlates (GenVault, Carlsbad, CA).
    Biopreservation and Biobanking 12/2010; 8(4):193-6. DOI:10.1089/bio.2010.0017 · 1.34 Impact Factor
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    ABSTRACT: Large studies may identify postulated risk factors and interventions with very small effect sizes. We aimed to assess empirically a large number of statistically significant relative risks (RRs) of tiny magnitude and their interpretation by investigators. RRs in the range between 0.95 and 1.05 were identified in abstracts of articles of cohort studies; articles published in NEJM, JAMA or Lancet; and Cochrane reviews. For each eligible tiny effect and the respective study, we recorded information on study design, participants, risk factor/intervention, outcome, effect estimates, P-values and interpretation by study investigators. We also calculated the probability that each effect lies outside specific intervals around the null (RR interval 0.97-1.03, 0.95-1.05, 0.90-1.10). We evaluated 51 eligible tiny effects (median sample size 112 786 for risk factors and 36 021 for interventions). Most (37/51) appeared in articles published in 2006-10. The effects pertained to nutrition (n = 19), genetic and other biomarkers (n = 8), correlates of health care (n = 8) and diverse other topics (n = 16) of clinical or public health importance and mostly referred to major clinical outcomes. A total of 15 of the 51 effects were >80% likely to lie outside the RR interval 0.97-1.03, but only 8 were >40% likely to lie outside the RR interval 0.95-1.05 and none was >1.7% likely to lie outside the RR interval 0.90-1.10. The authors discussed at least one concern for 23 effects (small magnitude n = 19, residual confounding n = 11, selection bias n = 1). No concerns were expressed for 28 effects. Statistically significant tiny effects for risk factors and interventions of clinical or public health importance become more common in the literature. Cautious interpretation is warranted, since most of these effects could be eliminated with even minimal biases and their importance is uncertain.
    International Journal of Epidemiology 07/2011; 40(5):1292-307. DOI:10.1093/ije/dyr099 · 9.18 Impact Factor
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    ABSTRACT: Biomarkers and metabolites related to B vitamin function and one-carbon metabolism have been studied as predictors of chronic diseases in studies based on samples stored in biobanks. For most biomarkers, stability data are lacking or fragmentary. Degradation and accumulation kinetics of 32 biomarkers were determined at 23 °C in serum and plasma (EDTA, heparin, and citrate) collected from 16 individuals and stored for up to 8 days. In frozen serum (-25 °C), stability was studied cross-sectionally in 650 archival samples stored for up to 29 years. Concentration vs time curves were fitted to monoexponential, biexponential, linear, and nonlinear models. For many biomarkers, stability was highest in EDTA plasma. Storage effects were similar at room temperature and at -25 °C; notable exceptions were methionine, which could be recovered as methionine sulfoxide, and cystathionine, which decreased in frozen samples. Cobalamin, betaine, dimethylglycine, sarcosine, total homocysteine, total cysteine, tryptophan, asymetric and symmetric dimethyl argenine, creatinine, and methylmalonic acid were essentially stable under all conditions. Most B vitamins (folate and vitamins B2 and B6) were unstable; choline increased markedly, and some amino acids also increased, particularly in serum. The kynurenines showed variable stability. For many biomarkers, degradation (folate and flavin mononucleotide) or accumulation (pyridoxal, riboflavin, choline, amino acids) kinetics at room temperature were non-first order. Data on stability and deterioration kinetics for individual biomarkers are required to optimize procedures for handling serum and plasma, and for addressing preanalytical bias in epidemiological and clinical studies.
    Clinical Chemistry 12/2011; 58(2):402-10. DOI:10.1373/clinchem.2011.174490 · 7.91 Impact Factor
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