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Summary. Background: Numerous case-control studies have reported higher prevalence of non-O blood type among venous thromboembolism (VTE) patients than controls, but potential mechanisms or effect modifiers for the association are not fully established. Patients/methods: Using a nested case-control design combining the Atherosclerosis Risk in Communities and the Cardiovascular Health Study cohort, ABO blood type and other VTE risk factors were measured on pre-event blood samples of 492 participants who subsequently developed VTE and 1008 participants who remained free of VTE. Results: A total of 64.4% of cases and 52.5% of controls had non-O blood type. Among controls, mean values of factor VIIIc (FVIIIc) and von Willebrand factor among the non-O blood type group were higher than among the O group. Compared with O blood type, the age-adjusted odds ratio (OR) of VTE for non-O blood type was 1.64 (95% CI, 1.32-2.05) and was similar for the two parent studies and race groups. Further adjustment for sex, race, body mass index, diabetes mellitus and FVIIIc reduced the OR: 1.31 (95% CI, 1.02-1.68). Factor V Leiden (FV Leiden) appeared to modify the non-O blood type association with VTE in a supraadditive fashion, with an age-, sex-and race-adjusted OR of 6.77 (95% CI, 3.65-12.6) for having both risk factors. Conclusions: Non-O blood type was independently associated with risk of VTE, and added to the risk associated with FV Leiden.

Methionine sulfoxide reductase maintains adhesin function during oxidative stress. Using Streptococcus gordonii as a model, we now show the mechanistic basis of adhesin maintenance provided by MsrA. In biofilms, S. gordonii selectively expresses the msrA gene. When the wild-type strain was grown with exogenous hydrogen peroxide (H2O2), msrA-specific mRNA expression significantly increased, while acid production was unaffected. In the presence of H2O2, an msrA-deletion mutant (ΔMsrA) showed a 6 h delay in lag phase growth, a 30% lower yield of H2O2, significantly greater inhibition by H2O2 on agar plates (reversed by complementation), 30% less adhesion to saliva-coated hydroxyapatite, 87% less biofilm formation, and an altered electrophoretic pattern of SspAB protein adhesins. Using mass spectrometry, methionine residues in the Met-rich central region of SspB were shown to be oxidized by H2O2 and reduced by MsrA. In intact wild-type cells, MsrA co-localized with a cell wall-staining dye, and MsrA was detected in both cell wall and cytosolic fractions. To maintain normal adhesion and biofilm function of S. gordonii in response to exogenous oxidants, therefore, msrA is up-regulated, methionine oxidation of adhesins and perhaps other proteins is reversed, and adhesion and biofilm formation is maintained.

Recent studies have observed enhanced degradation of methyl isothiocyanate (MITC) from repeated fumigation in agricultural soils. Little is known about fumigant degradation in forest and nursery soils. This study was conducted to determine degradation rates of MITC and chloropicrin (CP) in two forest soils and the impacts of nursery management on degradation of MITC and CP. The half-life values of MITC and CP were evaluated in the laboratory under isothermal conditions (22 +/- 2 degrees C). Three rates representing 0.5x, 1x, and 2x field application rates for each fumigant were used in laboratory incubations. Effect of microbial degradation was determined by conducting incubations with both fresh and sterilized soils. Soil moisture effects were also studied. There was no difference in MITC or CP degradation between fumigated and nonfumigated forest nursery soils. Soil sterilization and high soil moisture content (15% by wt.) reduced MITC and CP degradation. The degradation rates of MITC and CP varied with factors such as nursery history, fumigant application rates, and freshness of tested soils.