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March 1, 2007
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March 22, 2007
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The Human Genome and HapMap projects have provided the tools and information that will aid in understanding how nutrients alter the expression of an individual's genetic information and why individuals differ in metabolism of foods at the molecular level. The study of how genes and gene products interact with dietary chemicals to alter phenotype and, conversely, how genes and their products metabolize nutrients is called nutritional genomics or “nutrigenomics.” This new field has received considerable attention in the last 6 years, most of which has been on the promise rather than on scientific results from nutrigenomic experiments. Funding for nutrigenomics research focused primarily on individual laboratory projects in the 1990s and early 2000s. The novelty of combining nutrition and genetics limited that funding to a relatively small number of laboratories. Only in the past 3 years have centers been funded to foster collaborations and conduct large-scale projects that are studying nutrient-gene interactions. The increase in interest and funding is beginning to generate the critical mass to realize the promise of nutritional genomics. Clin Chem Lab Med 2007;45:279–87.
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March 1, 2007
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Proteomics, the comprehensive analysis of a protein complement in a cell, tissue or biological fluid at a given time, is a key platform within the “omic” technologies that also encompass genomics (gene analysis), transcriptomics (gene expression analysis) and metabolomics (metabolite profiling). This review summarises protein pre-separation, identification, quantification and modification/interaction analysis and puts them into perspective for nutritional R&D. Mass spectrometry has progressed with regard to mass accuracy, resolution and protein identification performance. Separation, depletion and enrichment techniques can increasingly cope with complexity and dynamic range of proteomic samples. Hence, proteomic studies currently provide a broader, albeit still incomplete, coverage of a given proteome. Proteomics adapted and applied to nutrition and health should demonstrate ingredient efficacy, deliver biomarkers for health and disease disposition, help in differentiating dietary responders from non-responders, and discover bioactive food components. Clin Chem Lab Med 2007;45:288–300.
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March 1, 2007
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The current worldwide prevalence of type 2 diabetes (T2D) was estimated to be 2.8% in 2000, but it is predicted to increase to epidemic proportions in the coming decades, primarily due to lifestyle changes, particularly obesity. In the United Kingdom there are over 1.4 million men and women with T2D. In addition to a strong environmental element, the existence of an underlying genetic component to T2D risk is supported by twin studies, family studies and the widely different T2D prevalence across ethnic groups. Here we review data showing that several common genetic risk variants for T2D have now been successfully identified, with modest, but meta-analytical robust effects on risk (in the region of 1.1–1.5-fold risk per allele). Use of these in combination may have clinical utility in identifying subjects at high risk. Whether this information will be motivating to make the type of lifestyle changes that have been shown to reduce the rate of progression from the pre-diabetes state to overt T2D is discussed. Clin Chem Lab Med 2007;45:301–8.
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March 1, 2007
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Background : There is limited evidence on the role of genetic and environmental factors in the etiology of childhood obesity, a major health problem worldwide. Methods : The Gene-Diet Attica Investigation on childhood obesity (GENDAI) evaluates the contributions to and pivotal interactions of genetic, dietary and physical activity variables on children's weight. We describe the design, methodology, and present preliminary data. So far, 920 participants have been enrolled and the final projected sample is 1000 fifth- and sixth-grade students from selected elementary schools in Attica (10–14 years). In this school-based cross-sectional study, more than 400 variables describing anthropometric, dietary, clinical, genetic, sociodemographic and other lifestyle characteristics were collected from participating children and their families. Results : Increased body mass index was identified in 39.3% of subjects (30.5% overweight and 8.8% obese), with males presenting a more unfavorable metabolic profile, i.e., higher blood lipids, glucose, and insulin, compared to females. Normal-weight children had a significant advantage when compared to all children of increased weight in terms of lipid profile and insulin, as well as behaviors examined. Specifically, normal-weight children exhibited less skipping of meals and less sedentary activities. Conclusions : The overall high prevalence of overweight and obesity in the current population is significant and underscores the need for environmental and genetic information that will shed light on the phenomenon of childhood obesity. Clin Chem Lab Med 2007;45:309–15.
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March 22, 2007
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Background : The relationship between dietary composition and plasma lipids is to some extent genetically determined. It has been found that variants of some genes (e.g., apolipoprotein E and cholesterol 7-α hydroxylase) play an important role in changes in plasma lipid levels in response to dietary intervention. We analyzed the effect of variation in the apolipoprotein ( APO ) APOA1/C3/A4/A5 gene cluster on decreases in plasma cholesterol levels over an 8-year follow-up study. Methods : Men (n=133) from the Czech population, for which dietary composition has markedly changed (red meat 80→68 kg/person/year, animal fat 16→9 kg/person/year, fruits and vegetables 133→150 kg/person/year) were recruited. APOA1 (G–75>A and C83>T), APOC3 (C–482>T and C3238>G), APOA4 (Thr347>Ser and Gln360His) and APOA5 (T–1131>C, Ser19>Trp and Val153>Met) variants were analyzed by PCR and restriction analysis. Lipid levels were analyzed in 1988 and 1996. Dietary information was obtained from the Institute of Agricultural Economy. Results : In APOA5 Ser19Ser homozygotes (n=105), plasma cholesterol was relatively stable over the years (6.1±1.3 and 5.6±1.0 mmol/L in 1988 and 1996), but the decrease was much higher in Trp19 carriers (n=27; 6.5±1.6 vs. 5.1±1.1 mmol/L). This difference in change is significant at p<0.005. Similarly, a better response to dietary changes was detected in carriers of the common APOA4 haplotypes Thr-347Thr/Gln360Gln and Thr347Ser/Gln360Gln (n=102; 6.3±1.3 and 5.5±1.1 mmol/L in 1988 and 1996, p<0.001). Total cholesterol was relatively stable over time in carriers (n=18) of at least one His360 allele and/or two Ser347 alleles (5.7±1.1 and 5.5±0.9 mmol/L in 1988 and 1996, n.s.). Other variants analyzed did not influence the change in lipid measurements over time. Conclusions : APOA4 and APOA5 variants may play an important role in the individual sensitivity of lipid parameters to dietary composition in men. Clin Chem Lab Med 2007;45:316–20.
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March 1, 2007
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The phenotype of an individual is the result of complex interactions between genotype, epigenome and current, past and ancestral environment, leading to lifelong remodelling of our epigenomes. Various replication-dependent and -independent epigenetic mechanisms are involved in developmental programming, lifelong stochastic and environmental deteriorations, circadian deteriorations, and transgenerational effects. Several types of sequences can be targets of a host of environmental factors and can be associated with specific epigenetic signatures and patterns of gene expression. Depending on the nature and intensity of the insult, the critical spatiotemporal windows and developmental or lifelong processes involved, these epigenetic alterations can lead to permanent changes in tissue and organ structure and function, or to reversible changes using appropriate epigenetic tools. Given several encouraging trials, prevention and therapy of age- and lifestyle-related diseases by individualised tailoring of optimal epigenetic diets or drugs are conceivable. However, these interventions will require intense efforts to unravel the complexity of these epigenetic, genetic and environment interactions and to evaluate their potential reversibility with minimal side effects. Clin Chem Lab Med 2007;45:321–7.
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March 1, 2007
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Obesity is thought to be a major determinant in the development of cardiovascular diseases, but the mechanisms whereby enlarged adipose tissue affects vascular function remain poorly defined. Chronic inflammation is a common feature of obesity and atherosclerosis, and several inflammatory markers produced by adipose tissue have been considered as candidates that potentially favor the development of atherosclerostic lesions in humans. To identify other effective candidates, we combined bioclinical data for individuals of increasing weight with adipose tissue gene-expression profiling. This strategy led to the discovery of cathepsin S (CTSS), for which gene expression was strongly correlated with subjects' body mass index (BMI). CTSS is an elastolytic cysteine protease that has been implicated in the development of atherosclerotic lesions in both animal models and humans. In this review, we discuss the role of CTSS in obesity and atherosclerosis, and emphasize the potential mechanisms that could link the two diseases. We also position this protease as a potential therapeutic target to reduce associated cardiovascular risks in obese patients. Clin Chem Lab Med 2007;45:328–32.
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March 22, 2007
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Background: The T-box21 ( TBX21 ) gene encodes the transcription factor T-bet (T-box expressed in T-cells), which influences naive T-lymphocyte development and has been implicated in the pathogenesis of many diseases. Methods: We selected 208 hepatitis B patients and 213 healthy volunteers to examine whether polymorphisms or haplotypes of the TBX21 gene promoter were associated with hepatitis B virus (HBV) infection in the Chinese population. Two polymorphisms at −1499 and −1514 located in the TBX21 promoter region were identified by the PCR-restriction fragment length polymorphism (PCR-RFLP) method. Results: Single nucleotide polymorphism (SNP) at −1499 was significantly different between HBV patients and healthy controls [p = 0.003; odds ratio (OR) 3.65, 95% confidence interval (CI) 1.58–8.45]. Similarly, our results showed a significantly higher level of haplotype D (--/AC) in HBV patients compared to control subjects (p = 0.005; OR 4.82, 95% CI 1.59–14.61). Conclusions: Based on our findings, it seems that genetic variations of allele −1499 and haplotype D (--/AC) within the TBX21 promoter region contribute to susceptibility to HBV infection in the Chinese population. Clin Chem Lab Med 2007;45:333–8.
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March 22, 2007
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Background : Two-colour flow cytometry was compared with multiplex PCR with capillary electrophoresis for clonality determination in specific categories of B-cell lymphoma. FTA cards were evaluated for preserving DNA from node imprints and expediting molecular analysis. Methods : A single-tube multiplex PCR targeted IGH and lymphoma-specific translocations in DNA extracted from 180 frozen lymphoid tissues and DNA bound to FTA cards from 192 fresh tissues and 137 aspirates. PCR results were compared with flow cytometry in the extracted and aspirated samples. Results : Overall, single-tube multiplex PCR sensitivity was equivalent in the sample groups (intergroup range 79%–91%). False negatives were associated with tumour origin in the follicle centre. Multiplex PCR and flow cytometry were equally sensitive and together detected 98% of B-cell lymphomas. Additional two-tube targeting of IGK suggested an overall molecular sensitivity >90%. False positive (pseudoclonal) single-tube multiplex PCR was associated with necrosis and sparse lymphocytes. Conclusions : Multiplex PCR using template DNA bound to an FTA card effectively detects B-lymphocyte clonality, obviates DNA extraction and refrigeration, and can be used without diminished sensitivity in fine needle aspirates or node imprints as a replacement for or complement to flow cytometry at any point in the diagnostic work-up. Clin Chem Lab Med 2007;45:339–45.
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March 1, 2007
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Background : Apolipoprotein E ( APOE ) and choline acetyltransferase ( ChAT ) have been suggested as candidate genes for determining the risk of late-onset Alzheimer's disease. The aim of this study was to simultaneously detect polymorphisms in codons 112 and 158 of APOE and codon 2 of ChAT by hybridization probe multiplexing. Methods : The decrease in fluorescence emitted by LC-Red 610, LC-Red 640, and LC-Red 705 channels was quantified during a gradual temperature increase after amplification. The melting curves were converted to melting peaks by plotting the negative derivative of the fluorescence with respect to temperature (–dF/dT) as a function of temperature. A single pair of hybridization probes and PCR restriction fragment length polymorphism (RFLP) were used to confirm the genotyping of APOE and ChAT , respectively, in 183 subjects. Results : When a homozygous sample with the CGC/CGC sequence in codon 112 of APOE was analyzed, the mean sequence-specific melting point (T m ) was 62.8°C, whereas a sample with the TGC/TGC sequence had a T m of 54.7°C. A similar fluorescence pattern appeared with a different T m at 66.9°C (CGC/CGC) and 59.7°C (TGC/TGC) for codon 158 of APOE . For the ChAT polymorphism, the melting temperature (61.4°C) of the G allele was higher than that of the A allele (54.7°C). Conclusions : This real-time multiplex PCR technique can be carried out in a single tube and can differentiate between the three polymorphic sites of the two genes associated with Alzheimer's disease. Clin Chem Lab Med 2007;45:346–50.
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March 22, 2007
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Background : Cytokeratin 20 reverse transcriptase polymerase chain reaction (CK20 RT-PCR) of blood and bone marrow specimens has been suggested for assessment of hematogenously disseminated tumor cell (DTC) spread in colorectal cancer (CRC) patients. Considerable discrepancies among the studies reported indicate a need for better evaluation procedures. We investigated whether mononucleated cell (MNC) enrichment by Ficoll density gradient centrifugation followed by immunomagnetic depletion of CD45-positive cells (extended enrichment) allows better detection of DTC-associated CK20 mRNA compared to MNC enrichment by Ficoll density gradient centrifugation alone (Ficoll enrichment). Methods : We analyzed 53 samples [38 peripheral blood (PB), 15 bone marrow (BM)] from 38 CRC patients. Extended enrichment was performed for 30 specimens (PB and BM, n=15 each), and Ficoll enrichment for 23 blood specimens. Total RNA was extracted, reverse-transcribed and analyzed by real-time RT-PCR using a LightCycler instrument. Results : Despite extended enrichment, 10 PB and 8 BM samples could not be analyzed because of low cellular yield. The depletion efficiency of CD45 separation was 2 log. RT-PCR of the housekeeping gene PBGD resulted in high and varied crossing point values (mean 37.1+3.0) for five PB and seven BM specimens. Ficoll enrichment yielded 23 analyzable blood specimens for which the mean crossing point value was 26.7+0.5 in PBGD RT-PCR. CK20 RT-PCR of 23 blood samples (all from Dukes D patients) revealed CK20 transcripts in four cases (17%). Conclusions : Extended enrichment was not superior to Ficoll enrichment; in fact, the sensitivity was lower. Improvement of the reported CK20 RT-PCR assay of Ficoll-enriched MNC populations is warranted. Clin Chem Lab Med 2007;45:351–6.
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March 1, 2007
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Background : The increase in plasma aspartate (AST) and alanine (ALT) aminotransferase after liver resection is multifactorial, and a major problem is the difficult quantification of the impact of each factor involved. Methods : Regression analysis of a large series of measurements for 92 hepatectomy patients was carried out to assess in detail the postoperative evolution of AST and ALT, together with related components. Results : The best correlate of increased AST and ALT on postoperative day 1 was the duration of surgery (T-surg) (r 2 =0.31 and 0.29), with a lower correlation for intraoperative liver ischemia (T-isch) (r 2 =0.22 and 0.17, respectively; p<0.001 for all). Subsequently AST decreased more quickly than ALT and both followed an inverse exponential pattern. T-surg, T-isch, time after surgery and plasma bilirubin explained 77% and 51% of the variability of AST and ALT, respectively, for all postoperative measurements (p<0.001 for both). The best correlate of T-isch was a delayed increase in bilirubin, detected on postoperative day 7, attenuated by the use of intermittent liver ischemia. Conclusions : These data show that T-isch may not be the main determinant of increased transaminases after hepatectomy, and provide a quantitative analysis of the main impact of the trauma of liver resection, liver ischemia, and other factors on the postoperative evolution of transaminases. Clin Chem Lab Med 2007;45:357–60.
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March 22, 2007
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Background : The levels and fine structure of complex polysaccharides, glycosaminoglycans (GAGs), were determined in segments of the posterior mitral valve leaflet (MVL) taken from 15 patients affected by mitral regurgitation and degenerative disease and were compared with segments from 15 multiorgan donors. Methods : MVL GAGs were analyzed by agarose gel electrophoresis, and by HPLC and fluorophore-assisted carbohydrate electrophoresis to evaluate disaccharide patterns after treatment with chondroitinase ABC. Results : GAGs from the control group were composed of approximately 37% hyaluronic acid and 63% chondroitin sulfate/dermatan sulfate with a charge density of approximately 0.61. Chondroitin sulfate/dermatan sulfate polymers contained approximately 23% of the disaccharide sulfated in position 6 on N-acetyl-galactosamine, ∼38% of the 4-sulfated disaccharide and ∼2% of the non-sulfated disaccharide (with a 4-sulfated/6-sulfated ratio of 1.7). The total amount of GAGs was 0.66 μg/mg tissue. The total amount of GAGs in patients suffering from mitral regurgitation and degenerative disease was approximately 51.5% higher (although the difference was not significant, probably because of the low number of subjects enrolled in the study). However, significantly higher hyaluronic acid content (approx. +38%, p<0.05) and lower sulfated GAG content (approx. −21%, p<0.005) were demonstrated. As a consequence, the total charge density decreased by approximately 23% (p<0.005). This macromodification of GAG composition was also followed by a microalteration of the structure of the sulfated polysaccharides, in particular with a significant decrease in the 4-sulfated disaccharide (and a parallel increase in hyaluronic acid content) with no modification of the percentage of the 6-sulfated and non-sulfated disaccharides (with a significant decrease in the 4-/6-sulfated ratio). Conclusions : We assume that changes in the relative amount and distribution of GAGs in posterior MVL in subjects suffering from mitral regurgitation and degenerative disease are consistent with a decrease in the tension to which these tissues are subjected and with an abnormal matrix microstructure capable of influencing the hydration and of conditioning the mechanical weakness of these pathological tissues. Clin Chem Lab Med 2007;45:361–6.
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March 1, 2007
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Background : Reactive oxygen species (ROS) play a major role in the pathogenesis of different chronic and degenerative diseases, including atherosclerosis. However, the lack of feasible and reliable methods limits the spread of oxidative stress estimation for routine application in clinical chemistry laboratories. We have recently evaluated the analytical characteristics of an automated test for the measurement of hydroperoxides (HPs) and its performance in determining oxidative stress levels in a general population. In this study we applied this method for the evaluation of oxidative stress in a cohort of patients with coronary artery disease (CAD). Methods : A total of 69 patients with angiographically verified CAD and 34 age- and sex-matched control subjects were enrolled in the study. Results : HPs were higher in patients with CAD (p<0.01), significantly increasing with disease severity (p<0.01). HPs were also higher in subjects with diabetes, dyslipidemia or C-reactive protein >1.5mg/L. A significant positive correlation was observed between glucose and HP levels. In a multivariate model, diabetes (odds ratio OR=3.5, 95% CI 1.2–10, p<0.05) and CAD (OR=5.7, CI 1.1–28.5, p<0.05) were independent determinants for the 75th HP percentile. Conclusions : The results obtained with this method largely reproduce those found using other oxidative stress biomarkers, but the method is faster, easy to perform and does not require skilled operators or complex instrumentation, and thus is a reliable procedure that might represent a feasible tool for oxidative stress estimation in the cardiovascular setting. Clin Chem Lab Med 2007;45:367–71.
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March 22, 2007
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Background : Cardiopulmonary bypass (CPB) has long been recognised as a main cause of a postoperative complex systemic inflammatory response after coronary artery bypass grafting (CABG). Methods : We determined the kinetics of peripheral blood release of the novel inflammatory biomarkers secretory phospholipase A 2 (sPLA 2 ), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) during the first 6 days following surgery in 16 patients undergoing CABG with (on-pump, n=9) or without (off-pump, n=7) CPB. Kinetic curves for these markers were compared to those of the well-known inflammatory parameters C-reactive protein (CRP) and fibrinogen. Results: sPLA 2 activity exhibited a maximum value on day 2, then decreased until day 6 for both groups and in a similar manner as CRP levels. On the other hand, elevation of plasma levels of both MMP-9 and TIMP-1 occurred as early as on day 1 and remained at this level until day 6. No significant difference in kinetic characteristics (peak value, area under the curve, initial slope) between CABG with and without CPB was observed. Conclusions : These data show that the off- and on-pump groups did not show significantly different kinetics for the releases of all biomarkers studied, including sPLA 2 and biomarkers of the MMP-TIMP network. The off-pump procedure may therefore lead to global surgical trauma as important as CPB in terms of the systemic inflammatory process and matrix proteolysis pathway activation. Clin Chem Lab Med 2007;45:372–5.
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March 1, 2007
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Background : Blood platelet counts (PCs) play a role in the development of cardiovascular disease (CVD). The metabolic syndrome (MS) is also associated with high CVD risk. However, the connection between PCs and MS has not yet been thoroughly investigated in relation to various biosocial factors that can affect both PCs and the pathophysiology of MS. Methods : A total of 152 asymptomatic female subjects (mean age 50 years) with almost normal levels of hemoglobin and white blood cell counts were recruited. MS was diagnosed according to the NCEP-ATP III criteria with a minor modification. The relationships between PCs and MS were analyzed according to the number of MS components (0, 1–2, ≥3). Biosocial factors including age and some lifestyle factors (smoking, alcohol intake and physical activity) were included in the analyses. Results : PCs in subjects with ≥3 MS components (233±43 [SD]×10 9 /L) were strikingly and significantly higher than in subjects with 0 (194±34×10 9 /L) or 1–2 MS components (207±38×10 9 /L). General linear model analysis for PCs, adjusted for all biosocial factors and number of MS components, revealed a significant and positive correlation between PCs and number of MS components (p<0.0001). Conclusions : The results suggest that PCs may be a potential marker associated with clustered MS components, independent of some biosocial factors, in Japanese females. Clin Chem Lab Med 2007;45:376–9.
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March 1, 2007
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Background: Vitamin B 12 and folate measurements in serum show wide inter-methodology variability. This variability appears to be due in part to the lack of standardisation against internationally accepted reference materials. Pooled human serum, lyophilised in ampoules and designated 03/178, was therefore evaluated by 24 laboratories in seven countries for its suitability to serve as an International Standard (IS) for B 12 and folate. Methods: IS 03/178 was assayed using a range of commercial analysers, microbiological assays and, for folate, candidate reference methods based on liquid chromatography coupled to isotope-dilution tandem mass spectrometry (LC/MS/MS). Results: Mean vitamin B 12 and folate values for reconstituted 03/178 across all laboratories and methods were 480 pg/mL [coefficient of variation (CV) 12.8%] and 5.52 ng/mL (CV 17.1%), respectively. The total folate content of reconstituted 03/178, determined using LC/MS/MS, was 12.1 nmol/L (equivalent to 5.33 ng/mL), made up of 9.75 nmol/L 5-methyl tetrahydrofolic acid (5MeTHF; CV 5.5%), 1.59 nmol/L 5-formyl tetrahydrofolic acid (5FoTHF; CV 4.2%) and 0.74 nmol/L folic acid (FA; CV 31.6%). The inclusion of three serum samples in the study with different B 12 and folate levels demonstrated a considerable reduction in inter-laboratory variability when the B 12 and folate content of the samples was determined relative to the IS 03/178 rather than to the analyser calibration. IS 03/178 demonstrated satisfactory long-term stability in accelerated degradation studies. Conclusions: Use of IS 03/178 to standardise serum B 12 and folate assays reduced inter-laboratory variability. The World Health Organization (WHO) Expert Committee on Biological Standardisation established 03/178 as the first IS for serum vitamin B 12 and serum folate, with assigned values of 480 pg/mL of vitamin B 12 and 12.1 nmol/L folate when the lyophilised contents of the ampoule are reconstituted with 1 mL of water. Clin Chem Lab Med 2007;45:380–6.
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March 1, 2007
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Background : Clinical laboratories seeking accreditation for compliance with ISO 15189:2003 need to demonstrate that the physiological reference intervals communicated to all users of the laboratory service are appropriate for the patient population served and for the measurement systems used. In the case of immunological quantities, few articles have been published in peer-reviewed journals. Methods : A total of 21 clinical laboratories in different regions of Spain collaborated in identifying reference individuals and determining adult reference intervals for some immunological quantities measured using RD/Hitachi Modular Analytics analysers and Tina-Quant ® reagent systems. These immunological quantities are the mass concentrations of immunoglobulin A, immunoglobulin G, immunoglobulin M, complement C3c and complement C4 in serum. All the logistic work was carried out in co-operation with the supplier of the reagents and analysers (Roche Diagnostics España, S.L., Sant Cugat del Vallès, Catalonia, Spain). From the set of reference values obtained by each laboratory, multicentre reference limits were estimated non-parametrically. Results and conclusions : The reference intervals estimated in this study for concentrations of serum components under consideration are: complement C3c, 0,62–1,64 g/L for women and men; complement C4, 0,14–0,72 g/L for women and men; immunoglobulin A, 0,89–4,80 g/L for women and men; immunoglobulin G, 6,5–14,3 g/L for women and men; and immunoglobulin M, 0,48–3,38 g/L for women and 0,41–2,46 g/L for men. (According to ISO, IUPAC and IFCC recommendations, the comma is used as the decimal sign.) Clin Chem Lab Med 2007;45:387–90.
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March 1, 2007
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Background : The in vivo skin prick test (SPT) is widely considered less expensive than in vitro γ-immunoglobulin E (IgE) determination in the diagnosis of allergy. The aim of the present paper is to evaluate the relevance of component-resolved in vitro diagnosis in comparison to extract-based diagnosis and the relative global costs in relation to clinical outcomes. Methods : For 50 individuals with suspected seasonal allergic rhinitis, we compared the costs of skin testing with those of specific IgE antibody measurement. Results : The costs were higher for in vitro than in vivo testing. However, the clinical information obtained using recombinant reagents allowed correct identification of the sensitizing molecule. Conclusions : Recombinant allergens for specific IgE in vitro measurement provide more reliable information for immunotherapy prescription. This should be translated into a significant reduction in the overall costs sustained by the healthcare system. Clin Chem Lab Med 2007;45:391–5.
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March 22, 2007
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Background : The European Directive 98/79/EC on in-vitro diagnostic medical devices (IVDs) regulates IVD marketing practices and post-market surveillance. IVD manufacturers have to inform the responsible Competent Authorities of any issues. In Germany, the Federal Institute for Drugs and Medical Devices (BfArM) is responsible for most IVDs, with a small subset of IVDs being within the responsibility of the Paul-Ehrlich-Institute (PEI). Methods : All IVD notifications received by BfArM between 1999 and June 2006 were analysed in terms of the source of notification, underlying product defects and corrective actions. Results : A total of 773 notifications were received, 566 related to IVDs for professional use and 207 related to over-the-counter (OTC) products for lay use. The latter included systems for blood glucose testing (analysers, tests and control materials; n=166) or coagulation testing (n=13) and pregnancy tests (n=25). Most reports came from manufacturers (n=115; 55.6%) and users (n=72; 34.8%) mainly via pharmacies and the Drug Commission of the German Pharmaceutical Association. Manufacturer investigations for all lay IVD cases reported revealed underlying product defects in 53 cases (25.6%). Product failure was excluded in 80 cases (38.6%), which included a large number of user errors (n=34). Many cases (n=74, 35.7%) could not be clarified because the test strips and/or analysers were not returned to the manufacturer for further investigation. In most cases, product defects identified by manufacturer investigations were related to the test strips and not to the analysers. Because of the high proportion of cases without proven product failure, corrective actions were performed only in a subset (n=54, 26.1%) of the cases reported for IVDs specified for lay use. Conclusions : The results show that the governmental system for post-marketing surveillance of IVDs is an established tool to ensure product safety. The proportion of notifications for OTC products indicates that they should be the focus for action by the competent surveillance authorities. Clin Chem Lab Med 2007;45:396–401.
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March 22, 2007
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Background : Implementation of high-sensitivity C-reactive protein (hs-CRP) assays as a routine laboratory parameter may be necessary. A single CRP method giving reliable results for the whole concentration range (0.1–160 mg/L) is the most practical solution for a laboratory. The aim of this study was to assess the Olympus CRP full-range immunoturbidimetric assay on an Olympus AU640 ® biochemistry analyser. Methods : CRP was determined in a population of patients simultaneously with the Randox CRP immunoturbidimetric assay and two immunonephelometric assays, the Dade Behring and Beckman Coulter CRP, on BN 100 and Immage systems, respectively. Results : Analytical performance, including precision and linearity, was excellent. The correlation coefficient for linear regression was r 2 =0.998, indicating that the assay method exhibited good linearity in the working range 0–160 mg/L. The intra- and inter-assay CVs for the Olympus CRP method were <3.6% over a wide range of CRP concentrations. Linear regression analysis indicated excellent agreement between CRP values for all patients, with correlation coefficients of r 2 >0.996, 0.993 and 0.989 for the Randox, Dade Behring and Beckman methods, respectively. Bland-Altman analyses demonstrated the excellent concordance of the CRP methods for patient samples. Conclusions : This study demonstrates that the new full-range Olympus method can be applied to measure CRP as a marker of inflammation and of cardiovascular risk. Clin Chem Lab Med 2007;45:402–6.
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March 1, 2007
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Background : Urinary microscopy is difficult to teach. This paper describes a 1-day course on urine microscopy, which was based on both theoretical and practical sessions at the microscope, during which real urine samples were examined. Methods : The course was based on: a) an introductory presentation with slides on the main components of urinary sediments and their clinical correlates; b) examination of fixed urine samples under the guidance of two experts; and c) the use of two microscopes, each equipped with a co-observation device for up to 15 observers. Results : Throughout 2005, four courses were held in four Italian towns. Altogether, there were 97 participants (20–27 per course) from 75 laboratories, all graduates with wide but variable experience in the field. During each course, 17–22 urinary sediment components were shown by both bright-field and phase-contrast microscopy and, when indicated, by polarized light. Tests set before and after the course showed a significant improvement (p<0.01) in the identification of erythrocyte subtypes, epithelial cells, fatty components, various types of casts and drug crystals. A questionnaire conducted with participants by phone several months after the course demonstrated that 51.6% and 32.3% of laboratories have introduced or formally requested phase-contrast and polarized-light microscopy, respectively; 45.2% have changed the terminology for urinary epithelial cells; and 87.1% have identified for the first time urinary sediment components that were not recognized or not considered before the course. Conclusions : Our course demonstrates that it is possible to improve the teaching of urinary microscopy. Clin Chem Lab Med 2007;45:407–12.
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Abstract
A large number of circumstances are associated with reduced serum concentrations of transthyretin (TTR), or prealbumin. The most common of these is the acute phase response, which may be due to inflammation, malignancy, trauma, or many other disorders. Some studies have shown a decrease in hospital stay with nutritional therapy based on TTR concentrations, but many recent studies have shown that concentrations of albumin, transferrin, and transthyretin correlate with severity of the underlying disease rather than with anthropometric indicators of hypo- or malnutrition. There are few if any conditions in which the concentration of this protein by itself is more helpful in diagnosis, prognosis, or follow up than are other clinical findings. In the majority of cases, the serum concentration of C-reactive protein is adequate for detection and monitoring of acute phase responses and for prognosis. Although over diagnosis and treatment of presumed protein energy malnutrition is probably not detrimental to most patients, the failure to detect other causes of decreased concentrations (such as serious bacterial infections or malignancy) of the so-called visceral or hepatic proteins could possibly result in increased morbidity or even mortality. In addition to these caveats, assays for TTR have a relatively high level of uncertainty (“imprecision”). Clinical evaluation – history and physical examination – should remain the mainstay of nutritional assessment. Clin Chem Lab Med 2007;45:419–26.
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