| 1. |
- Ahlqvist, Emma, et al.
(författare)
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Genetics of type 2 diabetes
- 2011
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 57:2, s. 241-254
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Forskningsöversikt (refereegranskat)abstract
- Background: Type 2 diabetes (T2D) is a complex disorder that is affected by multiple genetic and environmental factors. Extensive efforts have been made to identify the disease-affecting genes to better understand the disease pathogenesis, find new targets for clinical therapy, and allow prediction of disease.Content: Our knowledge about the genes involved in disease pathogenesis has increased substantially in recent years, thanks to genomewide association studies and international collaborations joining efforts to collect the huge numbers of individuals needed to study complex diseases on a population level. We have summarized what we have learned so far about the genes that affect T2D risk and their functions. Although more than 40 loci associated with T2D or glycemic traits have been reported and reproduced, only a minor part of the genetic component of the disease has been explained, and the causative variants and affected genes are unknown for many of the loci.Summary: Great advances have recently occurred in our understanding of the genetics of T2D, but much remains to be learned about the disease etiology. The genetics of T2D has so far been driven by technology, and we now hope that next-generation sequencing will provide important information on rare variants with stronger effects. Even when variants are known, however, great effort will be required to discover how they affect disease risk.
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| 2. |
- Hunter, Ingrid, et al.
(författare)
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N-Terminal Pro-Atrial Natriuretic Peptide Measurement in Plasma Suggests Covalent Modification
- 2011
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Ingår i: Clinical Chemistry. - : American Association for Clinical Chemistry. - 0009-9147 .- 1530-8561. ; 57:9, s. 1327-1330
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The N-terminal fragment of cardiac-derived pro-B-type natriuretic peptide is a glycosylated polypeptide. It is unknown whether N-terminal proatrial natriuretic peptide (proANP) fragments are also covalently modified. We therefore evaluated the clinical performance of 2 distinctly different proANP assays on clinical outcome. METHODS: We examined 474 elderly patients with symptoms of heart failure presenting in a primary healthcare setting. Samples were analyzed with an automated immunoluminometric midregion proANP (MR-proANP) assay and a new processing-independent assay (PIA) developed in our laboratory. The results were compared with Bland-Altman plots, and clinical performance was assessed by generating ROC curves for different clinical outcomes. RESULTS: Despite linear regression results indicating a good correlation (r = 0.85; P less than 0.0001), the PIA measured considerably more proANP than the MR-proANP assay (mean difference, 663 pmol/L; SD, 478 pmol/L). In contrast, the clinical performances of the 2 assays [as assessed by the area under the ROC curve (AUC)] in detecting left ventricular dysfunction were similar [proANP PIA, 0.71 (95% CI, 0.63-0.79); MR-proANP assay, 0.74 (95% CI, 0.66-0.81); P = 0.32]. The prognostic ability to report cardiovascular mortality during a 10-year follow-up revealed AUC values of 0.66 (95% CI, 0.60-0.71) for the proANP PIA and 0.69 (95% CI, 0.63-0.74) for the MR-proANP assay (P = 0.08, for comparing the 2 assays). CONCLUSIONS: Our data suggest that N-terminal proANP fragments in patient plasma differ from the calibrator peptides used but that the difference does not affect ROC curves in an elderly cohort of patients with mild to moderate heart failure. We suggest that human N-terminal proANP fragments can be covalently modified.
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| 3. |
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| 4. |
- Lund, Soren S., et al.
(författare)
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Agreement Between Fasting and Postprandial LDL Cholesterol Measured with 3 Methods in Patients with Type 2 Diabetes Mellitus
- 2011
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 57:2, s. 298-308
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: LDL cholesterol (LDL-C) is a modifiable cardiovascular disease risk factor. We used 3 LDL-C methods to study the agreement between fasting and postprandial LDL-C in type 2 diabetes (T2DM) patients. METHODS: We served 74 T2DM patients a standardized meal and sampled blood at fasting and 1.5, 3.0, 4.5, and 6.0 h postprandially. We measured LDL-C by use of modified beta quantification (MBQ), the Friedewald equation (FE), and a direct homogeneous assay (DA). We evaluated agreement using 95% limits of agreement (LOA) within +/- 0.20 mmol/L (+/- 7.7 mg/dL). RESULTS: LDL-C concentrations at all postprandial times disagreed with those at fasting for all methods. In 66 patients who had complete measurements with all LDL-C methods, maximum mean differences (95% LOA) in postprandial vs fasting LDL-C were -0.16 mmol/L (-0.51; 0.19) [-6.2 mg/dL (-19.7; 7.3)] with MBQ at 3 h; -0.36 mmol/L (-0.89; 0.17) [-13.9 mg/dL (-34; 6.6)] with FE at 4.5 h; and -0.24 mmol/L (-0.62; 0.05) [-9.3 mg/dL (-24; 1.9)] with DA at 6.0 h. In postprandial samples, FE misclassified 38% of patients (two-thirds of statin users) into lower Adult Treatment Panel III (ATP III) risk categories. Greater disagreement between fasting and postprandial LDL-C was observed in individuals with postprandial triglyceride concentrations >2.08 mmol/L (>184 mg/dL) and in women (interactions: P <= 0.038). CONCLUSIONS: Differences up to 0.89 mmol/L (34 mg/dL) between fasting and postprandial LDL-C concentrations, with postprandial LDL-C concentrations usually being lower, were found in T2DM by 3 different LDL-C methods. Such differences are potentially relevant clinically and suggest that, irrespective of measurement method, postprandial LDL-C concentrations should not be used to assess cardiovascular disease risk. (C) 2010 American Association for Clinical Chemistry
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| 5. |
- Rosenling, Therese, et al.
(författare)
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The Impact of Delayed Storage on the Measured Proteome and Metabolome of Human Cerebrospinal Fluid
- 2011
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 57:12, s. 1703-1711
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Because cerebrospinal fluid (CSF) is in close contact with diseased areas in neurological disorders, it is an important source of material in the search for molecular biomarkers. However, sample handling for CSF collected from patients in a clinical setting might not always be adequate for use in proteomics and metabolomics studies. METHODS: We left CSF for 0, 30, and 120 min at room temperature immediately after sample collection and centrifugation/removal of cells. After tryptic digestion at 2 laboratories by nanoLC Orbitrap-MS and chipLC QTOF-MS, CSF proteomes were analyzed. Metabolome analysis was performed at 3 laboratories by NMR, GC-MS, and LC-MS. Targeted analyses of cystatin C and albumin were performed by LC-MS/MS in the selected reaction monitoring mode. RESULTS: We did not find significant changes in the measured proteome and metabolome of CSF stored at room temperature after centrifugation, except for 2 peptides and 1 metabolite, 2,3,4-trihydrobutanoic acid, of 5780 identified peptides and 93 identified metabolites. A sensitive protein stability marker, cystatin C, was not affected. CONCLUSIONS: The measured proteome and metabolome of centrifuged, human CSF is stable at room temperature for up to 2 hours. We cannot exclude, however, that changes undetectable with our current methodology, such as denaturation or proteolysis, might occur due to sample handling conditions. The stability we observed gives laboratory personnel at the collection site sufficient time to aliquot samples before freezing and storage at -80 °C.
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| 6. |
- Sacks, David B., et al.
(författare)
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Executive Summary: Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus
- 2011
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 57:6, s. 793-798
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Multiple laboratory tests are used in the diagnosis and management of patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially. APPROACH: An expert committee compiled evidence-based recommendations for the use of laboratory analysis in patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. A draft of the guidelines was posted on the Internet, and the document was modified in response to comments. The guidelines were reviewed by the joint Evidence-Based Laboratory Medicine Committee of the AACC and the National Academy of Clinical Biochemistry and were accepted after revisions by the Professional Practice Committee and subsequent approval by the Executive Committee of the American Diabetes Association. CONTENT: In addition to the long-standing criteria based on measurement of venous plasma glucose, diabetes can be diagnosed by demonstrating increased hemoglobin A(1c) (Hb A(1c)) concentrations in the blood. Monitoring of glycemic control is performed by the patients measuring their own plasma or blood glucose with meters and by laboratory analysis of Hb A(1c). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed. SUMMARY: The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended. (C) 2011 American Association for Clinical Chemistry and American Diabetes Association
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| 7. |
- Sacks, David B., et al.
(författare)
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Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus
- 2011
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 57:6, s. 1-47
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Multiple laboratory tests are used to diagnose and manage patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these tests varies substantially. APPROACH: An expert committee compiled evidence-based recommendations for the use of laboratory testing for patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. Draft guidelines were posted on the Internet and presented at the 2007 Arnold O. Beckman Conference. The document was modified in response to oral and written comments, and a revised draft was posted in 2010 and again modified in response to written comments. The National Academy of Clinical Biochemistry and the Evidence Based Laboratory Medicine Committee of the AACC jointly reviewed the guidelines, which were accepted after revisions by the Professional Practice Committee and subsequently approved by the Executive Committee of the American Diabetes Association. CONTENT: In addition to long-standing criteria based on measurement of plasma glucose, diabetes can be diagnosed by demonstrating increased blood hemoglobin A(1c) (Hb A(1c)) concentrations. Monitoring of glycemic control is performed by self-monitoring of plasma or blood glucose with meters and by laboratory analysis of Hb A(1c). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed. SUMMARY: The guidelines provide specific recommendations that are based on published data or derived from expert consensus. Several analytes have minimal clinical value at present, and their measurement is not recommended. (C) 2011 American Association for Clinical Chemistry and American Diabetes Association
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| 8. |
- Shlipak, Michael G., et al.
(författare)
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Comparison of Cardiovascular Prognosis by 3 Serum Cystatin C Methods in the Heart and Soul Study
- 2011
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Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 57:5, s. 737-745
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cystatin C is a promising new biomarker to estimate glomerular filtration (eGFR). However, the Siemens' cystatin C assay (Siemens), used in many longitudinal studies, has had limited clinical applicability because it requires a specific, dedicated instrument. Other companies, including Gentian and Roche, have developed cystatin C assays that can be used with most routine clinical chemistry analyzers. METHODS: We compared the agreement of Gentian and Roche with Siemens in 948 participants at the baseline visit of the Heart and Soul Study, a cohort of participants with established coronary artery disease who were followed for an average of 8 years. We then compared associations of all 3 cystatin C measures and eGFR-Modification of Diet in Renal Disease (MDRD) with clinical outcomes. RESULTS: The Gentian assay had higher correlation with Siemens (r = 0.96) than did Roche (r = 0.93, P < 0.001). After cross-tabulating quartiles of each cystatin C measure, agreements (κ statistic) were higher for Siemens and Gentian (0.73, 95% CI 0.72-0.75) than for Roche and Siemens (0.64, 0.63-0.66) or for Roche and Gentian (0.69, 0.65-0.71). These differences in agreement had minimal impact on associations with clinical outcomes; the hazard ratios (HRs) for mortality comparing the high vs low quartiles were 3.2 (95% CI 2.1-4.8) for Siemens, 3.1 (CI 2.1-4.7) for Gentian, 3.1 (CI 2.1-4.7) for Roche, and 1.6 (CI 1.1-2.3) for eGFR-MDRD, after multivariate adjustment. CONCLUSIONS: In summary, agreement with the Siemens' assay was modestly higher for the Gentian compared with the Roche assay, although all 3 methods for cystatin C measurement had similar utility as predictors of clinical outcomes.
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