ABSTRACT
BACKGROUND: Genotyping for clinically important single nucleotide polymorphisms (SNPs) is performed by many clinical routine laboratories. To support testing, quality controls and reference materials are needed. Those may be derived from residual patient samples, left over samples of external quality assurance schemes, plasmid DNA or DNA from cell lines. DNAs from cell lines are commutable and available in large amounts. METHODS: DNA from 38 cell lines were examined for suitability as controls in 11 SNP assays that are frequently used in a clinical routine laboratory: FV (1691G>A), FII (20210G>A), PAI-1 4G/5G polymorphism, MTHFR (677C>T, 1298A>C), HFE (H63D, S65C, C282Y), APOE (E2, E3, E4), LPH (-13910C>T), UGT1A1 (*28, *36, *37), TPMT (*2, *3A, *3B, *3C), VKORC1 (-1639G>A, 1173C>T), CYP2C9 (*2, *3, *5). Genotyping was performed by real-time PCR with melting curve analysis and confirmed by bi-directional sequencing. RESULTS: We find an almost complete spectrum of genotypic constellations within these 38 cell lines. About 12 cell lines appear sufficient as genotypic controls for the 11 SNP assays by covering almost all of the genotypes. However, hetero- and homozygous genotypes for FII and the alleles TPMT*2, UGT1A1*37 and CYP2C9*5 were not detected in any of the cell lines. CONCLUSIONS: DNA from most of the examined cell lines appear suitable as quality controls for these SNP assays in the laboratory routine, as to the implementation of those assays or to prepare samples for quality assurance schemes. Our study may serve as a pilot to further characterize these cell lines to arrive at the status of reference materials.
Subject(s)
Clinical Laboratory Services/standards , Clinical Laboratory Techniques/standards , Genotyping Techniques/methods , Polymorphism, Single Nucleotide , Cell Line , Cell Line, Tumor , Clinical Laboratory Techniques/methods , Genotype , HL-60 Cells , Humans , K562 Cells , Quality Control , Reproducibility of ResultsABSTRACT
PURPOSE: Pulse wave velocity (PWV) is at least partially controlled by vascular tone. Vascular tone and underlying physiological processes such as sympathetic activity, plasma catecholamin, and cortisol levels have been shown to follow diurnal variations. MATERIALS AND METHODS: Carotid-to-radial PWV was non-invasively assessed by applanation tonometry in 21 young (26.5+/-2.3 years) healthy men at three different time points (8:00 hr, 12:00 hr, 17:00 hr) during a day. Additionally, heart rate, systolic, diastolic and mean blood pressure, and radial pulse pressure were assessed at the same time points. RESULTS: The mean PWV was significantly higher at 8:00 hr compared with the mean PWV assessed at later time points. No significant differences were found between mean PWV at 12:00 hr and at 17:00 hr. When PWV was corrected for blood pressure, the difference between values at 8:00 hr and 12:00 hr was no longer significant. Systolic, diastolic and mean blood pressure were significantly lower at 17:00 hr compared with those at 8:00 hr. CONCLUSION: A small but significant diurnal variation of PWV was observed in young healthy men, which might have been caused at least partly by variations of blood pressure. This finding could be of value, when PWV is used in human research. Thus, in longitudinal investigations the measurements should be performed at similar time points in the course of a day, in order to obtain comparable data. Additionally, our observations ought to be of assistance to studies in which novel pharmacological compounds with activity on the vasculature are investigated.
