Vasovagal reactions in blood donors during or immediately after blood donation.

The aim of the study was to estimate the type, incidence and causes of donor adverse reactions during and after blood donation in a Greek Blood Bank, where medical staff is responsible for donor selection. 12 173 blood donors were studied for adverse reactions. One-hundred and seven (0.87%) donors had a vasovagal reaction during or after blood donation. Donors who gave blood occasionally had a significant greater incidence of reactions compared with volunteer donors (1.15 versus 0.53%) (P < 0.001). There was no significant difference between men and women (0.85 versus 0.95%). First-time donors (1.7 versus 0.68%) and those under 30 years (1.15 versus 0.71%] had a significant greater possibility to have a reaction (P < 0.001). Twenty-two of 107 (20.5%) donors had a syncopal reaction. There was not a causative correlation of haematocrit, haemoglobin, systolic and diastolic blood pressure, pulse rate and weight in women (except weight in men) in developing a reaction. The stressing experience of phlebotomy was the reason for the higher frequency of a reaction. The incidence of reactions in our donors is lower than in other studies, and the possible reason for this is that only physicians are responsible for the selection of donors and trained personnel are careful of them during the donation process.

Prevalence of the G20210A prothrombin gene mutation in Northwestern Greece and association with venous thromboembolism.

AIM: The G20210A mutation of the prothrombin gene is a genetic risk factor for venous thromboembolism (VTE). Variability exists in the mutation prevalence in both normal individuals and VTE patients. The aim of this study was to determine the mutation prevalence in Northwestern Greece and evaluate its association with VTE. METHODS: Presence of the G20210A mutation was investigated using DNA analysis in 176 consecutive patients with a history of venous thrombosis or pulmonary embolism and in 300 healthy controls, all Caucasian residents of Northwestern Greece. RESULTS: The mutation was present 12 patients (6.8%) and 8 controls (2.7%). The odds ratio for presence of the mutation versus the normal genotype in VTE was 2.7 (95% CI: 1.1 to 6.7), which was statistically significant. The prevalence of the G20210A prothrombin gene mutation in Northwestern Greece is 2.7% (95% CI: 0.8% to 4.4%) with an allele frequency of 1.3% (95% CI: 0.4% to 2.3%). CONCLUSION: The G20210A mutation of the prothrombin gene is associated with VTE in the Caucasian residents of this geographic region.

Lack of association between the C677T mutation in the 5,10-methylenetetrahydrofolate reductase gene and venous thromboembolism in Northwestern Greece.

BACKGROUND: Hyperhomocysteinemia has been associated with venous thrombosis. Under known and unknown conditions the C677T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene is accompanied by elevated levels of homocysteine. However, the relationship of this mutation with venous thromboembolism (VTE) remains controversial. The purpose of this study was to evaluate the association of the MTHFR mutation with VTE. METHODS: The presence of the C677T mutation in the MTHFR gene was investigated in a population of 176 consecutive patients with a history of venous thromboembolism and in a control group of 300 healthy subjects, using DNA analysis. RESULTS: The prevalence of homozygosity in the patient group was 13.6% and in healthy subjects 10%. The odds ratio for venous thromboembolism in the presence of the homozygous genotype (677TT) was 1.4 (95% confidence interval (C.I.), 0.8 to 2.5), which was not statistically significant. CONCLUSIONS: Homozygosity for the T677 allele of the MTHFR gene, although slightly more prevalent in patients compared to controls, has not been found in association with venous thromboembolism.