198 research outputs found

    Thrombotic variables and risk of idiopathic venous thromboembolism in women aged 45-64 years - Relationships to hormone replacement therapy

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    Hormone replacement therapy (HRT) has been shown to increase the relative risk of idiopathic venous thromboembolism (VTE) about threefold in several observational studies and one randomised controlled trial. Whether or not this relative risk is higher in women with underlying thrombophilia phenotypes, such as activated protein C (APC) resistance, is unknown. We therefore restudied the participants in a case-control study of the relationship between the use of HRT and the occurrence of idiopathic VTE in women aged 45-64 years. After protocol exclusions, 66 of the cases in the original study and 163 of the controls were studied. Twenty haematological variables relevant to risk of VTE were analysed, including thrombotic states defined from the literature. The relative risk of VTE showed significant associations with APC resistance (OR 4.06; 95% CI 1.62, 10.21); low antithrombin (3.33; 1.15, 9.65) or protein C (2.93; 1.06, 8.14); and high coagulation factor IX (2.34: 1.26, 1.35), or fibrin D-dimer (3.84; 1.99, 7.32). HRT use increased the risk of VTE in women without any of these thrombotic static; (OR 4.09; 95% CI 1.26, 13.30). A similar effect of HRT use on the relative risk of VTE was also found in women with prothrombotic states. Thus for example, the combination of HRT use and APC resistance increased the risk of VTE about 13-fold compared with women of similar age without either APC resistance or HRT use (OR 13.27; 95%, CI 4.30, 40.97). We conclude that the combination of HRT use and thrombophilias (especially if multiple) increases the relative risk of VTE substantially; hence women known to have thrombophilias (especially if multiple) should be counselled about this increased risk prior to prescription of HRT. However. HRT increases the risk of VTE about fourfold even in women without any thrombotic abnormalities: possible causes are discussed

    Measurement of thrombosis and its prevention

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    Fibrin D-dimer, markers of coagulation activation and the risk of major ischaemic heart disease in the Caerphilly Study

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    We have previously reported that plasma fibrin D-dimer (a marker of turnover of cross-linked Fibrin) showed a strong and independent association with incident ischaemic heart disease (IHD) in the Caerphilly Study cohort of 1,998 men a-ed 49-65. To establish the specificity of this finding, we assayed plasma samples from this cohort with a more specific assay for fibrin D-dimer: this showed an association with incident IHD which was at least as strong and independent as that for the original assay (odds ratio, OR for top fifth compared to bottom fifth 3.79; 95% CI 1.77-8.10; p lt 0.0001). To establish potential causes of the increased fibrin turnover. we also assayed several potential markers of coagulation activation or thrombotic tendency (prothrombin fragment F1+2, thrombin- antithrombin complexes, factor VIIc, activated partial thromboplastin time [APTT] and activated protein C resistance): none of these variables were associated with incident IHD in this cohort. We suggest that further studies are required to establish the causes of increased cross-linked fibrin turnover, which is associated with incident IHD in the general population when measured by a specific assay

    Lifecourse social position and D-dimer; findings from the 1958 British birth cohort

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    The aim is to examine the association of lifecourse socioeconomic position (SEP) on circulating levels of D-dimer. Data from the 1958 British birth cohort were used, social class was determined at three stages of respondents' life: at birth, at 23 and at 42 years. A cumulative indicator score of SEP (CIS) was calculated ranging from 0 (always in the highest social class) to 9 (always in the lowest social class). In men and women, associations were observed between CIS and D-dimer (P<0.05). Thus, the respondents in more disadvantaged social classes had elevated levels of D-dimer compared to respondents in less disadvantaged social class. In multivariate analyses, the association of disadvantaged social position with D-dimer was largely explained by fibrinogen, C-reactive protein and von Willebrand Factor in women, and additionally by smoking, alcohol consumption and physical activity in men. Socioeconomic circumstances across the lifecourse at various stages also contribute independently to raised levels of D-dimer in middle age in women only. Risk exposure related to SEP accumulates across life and contributes to raised levels of D-dimer. The association of haemostatic markers and social differences in health may be mediated by inflammatory and other markers

    Virchow's triad revisited: Abnormal flow

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    HYPERFINE AND ZERO-FIELD SPLITTINGS IN THE 9Σ^{9}\Sigma GdO MOLECULE

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    Author Institution:The GdO molecule, produced by vaporization of solid Gd2O3Gd_{2}O_{3}, has been trapped in solid neon and argon matrices at 4K4^{\circ} K and studied via ESR spectroscopy. Fine structure and extra Lines (off-principal-axis absorptions) establish that the ground state is 9Σ^{9}\Sigma with a zero-field splitting parameter D|D| = =0.21(1) cm1cm^{-1} Weak 157Gd,155Gd^{157}Gd, ^{155}Gd hyperfine splittings are observed for each of the strong perpendicular lines

    Effects of moderate weight loss on anginal symptoms and indices of coagulation and fibrinolysis in overweight patients with angina pectoris

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    Objective: To evaluate the effects of moderate weight loss, in overweight patients with angina, on plasma coagulation, fibrinolytic indicies and pain frequency. Design: Single- stranded 12-week dietary intervention, an individualised eating plan with quantitative advice delivered by a dietitian. Target weight loss of 0.5 kg per week. Setting: Outpatient research clinic. Subjects: Fifty-four volunteers with angina pectoris were recruited. Five subjects withdrew, so 27 males, 22 females, mean body mass index (BMI) 29.3 (s.d. 4.3) kg/m(2) and age 60.3 (s.d. 6.5) y completed the intervention. Measurements: Body weight and frequency of anginal pain. Plasma fibrinogen, red cell aggregation (RCA), viscosity, factor VII activity, plasminogen activator inhibitor (PAI) activity, tissue plasminogen activator antigen (t-PA), plasma cholesterol, triglyceride and insulin. Results: After the 12-week dietary intervention period, mean body weight fell by 3.5 (s.d. 2.6) kg or 4.3% (P = 0.0001), range -11.7 to +1.7 kg. Mean angina frequency fell by 1.8 (s.d. 3.6) from 3.2 to 1.4 episodes/week (P = 0.009) and plasma cholesterol by 0.4 (s.d. 0.7) from 6.3 to 5.9 mmol/1 (P = 0.0001). HDL cholesterol and triglyceride were unchanged. Of the coagulation and fibrinolytic factors, factor VII activity and RCA were significantly reduced by 5 (s.d. 20), IU/dl (P = 0.04) and 1.3 (s.d. 1.3) arbitrary units (P = 0.014), respectively. Conclusions: A conventional dietetic intervention, resulting in 4% weight loss, offers the potential to reduce atherosclerotic and thrombotic risk, and to reduce pain frequency, in angina patients. Given the importance of this result in a public health context, these results indicate that this may be a fruitful area for future nutrition research
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