Thromboembolism in heart transplantation: role of prothrombin G20210A and factor V Leiden.

Background: Thromboembolism has been reported as a frequent complication after cardiac transplantation. Many risk factors for thrombosis may explain this, such as metabolic alterations and the use of cyclosporine. In the general population, two single nucleotide polymorphisms (SNPs), factor V Leiden and prothrombin G20210A (PT G20210A), have been associated with a significant increase in the risk of thrombosis.

Genetic polymorphisms predisposing to hyperhomocysteinemia in cardiac transplant patients.

Genetic determinants for high homocysteine (Hcy) levels are now well known. We studied several single nucleotide polymorphisms (SNP) in Hcy-regulating genes [methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C; methionine synthase (MS) A2756G; methionine synthase reductase (MTRR) A66G] in relation to total plasma Hcy levels, transplant coronary artery disease and thromboembolic episodes in 84 heart transplant patients, and we compared the incidence of these polymorphisms with those in a healthy adult controls. At least one copy of the G allele of the MTRR A66G SNP was found in a significantly greater proportion of cardiac transplant (CTX) recipients compared with controls (94.

Effects of folic acid fortification and multivitamin therapy on homocysteine and vitamin B(12) status in cardiac transplant recipients.

Background: Hyperhomocysteinemia is a frequent finding after cardiac transplantation, but increased folate intake induces a decrease in total homocysteine concentrations. In 1998, food in Canada was fortified nationwide with folic acid. We assessed the impact of routine folate fortification on homocysteine concentrations in our cardiac transplant population.

An improved assay for plasma methylmalonic acid using chemical ionization gas chromatography mass spectrometry.

Objectives: To develop a precise and sensitive assay for methylmalonic acid (MMA) using positive chemical ionization gas chromatography mass spectrometry (CI GC-MS), and to illustrate its clinical utility.

Methods: Using the developed assay, reference intervals were determined with 108 ambulatory individuals, and potential clinical utility examined in 178 consecutive patients with possible cobalamin deficiency (serum B12<200 nmol/L).

Results And Conclusions: Methylmalonic acid measured by CI GC-MS was precise (CV: 4-5%), and sensitive (limit of quantitation: 37 nmol/L).

Genetics University of Toronto Thrombophilia Study in Women (GUTTSI): genetic and other risk factors for venous thromboembolism in women.

BACKGROUND: Women may be at increased risk for venous thromboembolism (VTE) as compared with men. We studied the effects of genetic and biochemical markers of thrombophilia in women, in conjunction with other established risk factors for VTE. METHOD: The present retrospective case-control study was conducted in a thrombosis treatment programme at a large Toronto hospital.