In 2004 the Netherlands Twin Register (NTR) started a large scale biological sample collection in twin families to create a resource for genetic studies on health, lifestyle and personality. Between January 2004 and July 2008, adult participants from NTR research projects were invited into the study. During a home visit between 7:00 and 10:00 am, fasting blood and morning urine samples were collected. Fertile women were bled on day 2–4 of the menstrual cycle, or in their pill-free week. Biological samples were collected for DNA isolation, gene expression studies, creation of cell lines and for biomarker assessment. At the time of blood sampling, additional phenotypic information concerning health, medication use, body composition and smoking was collected. Of the participants contacted, 69% participated. Blood and urine samples were collected in 9,530 participants (63% female, average age 44.4 (SD 15.5) years) from 3,477 families. Lipid profile, glucose, insulin, HbA1c, haematology, CRP, fibrinogen, liver enzymes and creatinine have been assessed. Longitudinal survey data on health, personality and lifestyle are currently available for 90% of all participants. Genome-wide SNP data are available for 3,524 participants, with additional genotyping ongoing. The NTR biobank, combined with the extensive phenotypic information available within the NTR, provides a valuable resource for the study of genetic determinants of individual differences in mental and physical health. It offers opportunities for DNA-based and gene expression studies as well as for future metabolomic and proteomic projects.

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The laboratory diagnosis of von Willebrand disease (vWD) is complex and requires a panel of different laboratory tests. Because of this complexity, a proper quality control process is necessary. Since 2003, the European Concerted Action on Thrombosis and Disabilities Foundation has provided an external quality control program for several laboratory tests included in the diagnosis of vWD. Currently, ~180 different laboratories participate in this program, of which the vast majority perform both von Willebrand factor (vWF):antigen (Ag) and activity tests. The lowest between-laboratory variation was observed for the vWF antigen assay (10 to 24%), with a better performance for the latex immunoassay (8 to 24%) than the enzyme immunoassay (13 to 25%). Both the ristocetin cofactor activity assay (RCo) and the collagen-binding assay showed a higher between-laboratory variation (20 to 40% and 17 to 29%, respectively). We have observed that the within-laboratory repeatability for normal samples ranged from 0 to 40% for the antigen assay and from 0 to 86% for the ristocetin cofactor activity assay. Normal samples were interpreted correctly by the majority of the participants. However, type 1 vWD samples were wrongly interpreted by 20 to 40% of the participants, which was mainly caused by a discordance in the vWF:RCo/vWF:Ag ratio. It can be concluded that further improvement in the laboratory diagnosis of vWD is necessary.

This study provides evidence for an independent association of the insertion allele of the insertion/deletion polymorphism in the TPA gene with nonfatal MI. Increased TPA antigen is associated with an increased risk of MI; however, this association was not independent of cardiovascular disease risk factors.

Antithrombin is a serine protease inhibitor (serpin) that inhibits mainly thrombin (factor IIa) and factor Xa, but also factors VIIa, IXa, XIa, XIIa, kallikrein, and plasmin. Pharmacologically, heparin binds to antithrombin, exposing antithrombin's reactive site and accelerating antithrombin's activity approximately 1000-fold. Physiologically, heparan sulfate naturally lines endothelial cell surfaces, locally enhancing antithrombin's activity.Hereditary antithrombin deficiency is a hypercoagulable state with a 5-to-50-fold increased risk for venous thromboembolism (VTE). 1 Antithrombin deficiency has autosomal dominant inheritance, occurring in 0.02%-0.17% of the general population and in 1%-5% of patients with VTE. [1][2][3][4] The first VTE usually occurs between the ages of 10-50 years, which is similar to protein C and protein S

The detection and quantification of factor VIII (FVIII) inhibitors is clinically important both for the identification of hemophilia A patients with inhibitors and for the management of immune tolerance treatment. Only limited data are available on the between-laboratory variation of FVIII inhibitor testing. This report describes the evaluation of the results of the large-scale external quality assessment program of the European Concerted Action on Thrombosis Foundation. This study includes the results of six different surveys for the period 2006 to 2008 with 100 to 170 participating laboratories. The overall between-laboratory variation ranged from 28% to 52% with a slightly lower variation for the Nijmegen assay (approximately 39%) on average than for the Bethesda assay (approximately 45%). The use of buffered normal pooled plasma as FVIII source showed better performance compared with the use of nonbuffered pooled plasma; likewise the use of FVIII-deficient plasma compared with the use of imidazole buffer. However, the combination of both was essential for lowest between-laboratory variation. The Nijmegen assay also showed better performance with respect to specificity and sensitivity than the Bethesda assay, although the results for neither were entirely satisfactory. In general, it can be concluded that the measurement of FVIII inhibitory antibodies with the Nijmegen assay should be favored over the use of the Bethesda assay. However, further improvement of the laboratory test for FVIII inhibitors is urgently needed.

Abstract-Currently raloxifene, a selective estrogen receptor modulator, is being investigated as a potential alternative for postmenopausal hormone replacement to prevent osteoporosis and cardiovascular disease. We compared the 2-year effects of raloxifene on a wide range of cardiovascular risk factors with those of placebo and conjugated equine estrogens (CEEs). Analyses were based on 56 hysterectomized but otherwise healthy postmenopausal women aged 54.8Ϯ3.5 (meanϮSD) years who entered this double-blind study and who were randomly assigned to raloxifene hydrochloride 60 mg/d (nϭ15)

Bile acid synthesis, determined by conversion of [4-14C]cholesterol into bile acids in rat and human hepatocytes and by measurement of mass production of bile acids in rat hepatocytes, was dose-dependently decreased by cyclosporin A, with 52 % (rat) and 45 % (human) inhibition at 10/,M. The decreased bile acid production in rat hepatocytes was due only to a fall in the synthesis of,-muricholic and chenodeoxycholic acids (-64 % at 10 4M-cyclosporin A), with no change in the formation of cholic acid. In isolated rat liver mitochondria, 26-hydroxylation of cholesterol was potently inhibited by the drug (concn. giving half-maximal inhibition = 4/tM). These results suggest that cyclosporin A blocks the alternative pathway in bile acid synthesis, which leads preferentially to the formation of chenodeoxycholic acid.