Serum magnesium and calcium levels in relation to ischemic stroke : Mendelian randomization study

ObjectiveTo determine whether serum magnesium and calcium concentrations are causally associated with ischemic stroke or any of its subtypes using the mendelian randomization approach.MethodsAnalyses were conducted using summary statistics data for 13 single-nucleotide polymorphisms robustly associated with serum magnesium (n = 6) or serum calcium (n = 7) concentrations. The corresponding data for ischemic stroke were obtained from the MEGASTROKE consortium (34,217 cases and 404,630 noncases).ResultsIn standard mendelian randomization analysis, the odds ratios for each 0.1 mmol/L (about 1 SD) increase in genetically predicted serum magnesium concentrations were 0.78 (95% confidence interval [CI] 0.69-0.89; p = 1.3 7 10-4) for all ischemic stroke, 0.63 (95% CI 0.50-0.80; p = 1.6 7 10-4) for cardioembolic stroke, and 0.60 (95% CI 0.44-0.82; p = 0.001) for large artery stroke; there was no association with small vessel stroke (odds ratio 0.90, 95% CI 0.67-1.20; p = 0.46). Only the association with cardioembolic stroke was robust in sensitivity analyses. There was no association of genetically predicted serum calcium concentrations with all ischemic stroke (per 0.5 mg/dL [about 1 SD] increase in serum calcium: odds ratio 1.03, 95% CI 0.88-1.21) or with any subtype.ConclusionsThis study found that genetically higher serum magnesium concentrations are associated with a reduced risk of cardioembolic stroke but found no significant association of genetically higher serum calcium concentrations with any ischemic stroke subtype

Nanometer-micrometer sized depleted uranium (DU) particles in the environment.

Depleted uranium (DU) is a waste product from uranium enrichment that has several civilian and military applications. Significant amounts of DU in the form of particles or as fragments have been released into the environment as a consequence of military use of DU munitions, of industrial releases and of aircraft accidents. Thus, the present paper summarizes present knowledge on nanometer-micrometer sized depleted uranium (DU) particles collected in areas contaminated with such particles. Analysis of DU particles released to the environment has shown that uranium can be present in different crystalline structures and in different oxidation states. The weathering rates of DU particles and the subsequent remobilization of uranium species are also strongly connected to the oxidation state and crystalline phases of uranium, influencing the mobility and potential ecosystem transfer. Therefore, as has been observed for radioactive particles released from most nuclear events, the characteristics of DU particles can be linked to the source term and the release scenario as well as to environmental transformation processes. Although the radiation dose and radiotoxicity of DU is less than from natural occurring uranium, the mobility of U from oxidized DU and the associated chemical toxicity could be significantly higher than from natural UO2. The present paper summarizes present knowledge on depleted uranium particles identified in the environment

Solid state speciation and potential bioavailability of depleted uranium particles from Kosovo and Kuwait

A combination of synchrotron radiation based X-ray microscopic techniques (mu-XRF, mu-XANES, mu-XRD) applied on single depleted uranium (DU) particles and semi-bulk leaching experiments has been employed to link the potential bioavailability of DU particles to site-specific particle characteristics. The oxidation states and crystallographic forms of U in DU particles have been determined for individual particles isolated from selected samples collected at different sites in Kosovo and Kuwait that were contaminated by DU ammunition during the 1999 Balkan conflict and the 1991 Gulf war. Furthermore, small soil or sand samples heavily contaminated with DU particles were subjected to simulated gastrointestinal fluid (0.16 M HCl) extractions. Characteristics of DU particles in Kosovo soils collected in 2000 and in Kuwait soils collected in 2002 varied significantly depending on the release scenario and to some extent on weathering conditions. Oxidized U (+6) was determined in large, fragile and bright yellow DU particles released during fire at a DU ammunition storage facility and crystalline phases such as schoepite (UO(3).2.25H(2)O), dehydrated schoepite (UO(3).0.75H(2)O) and metaschoepite (UO(3).2.0H(2)O) were identified. As expected, these DU particles were rapidly dissolved in 0.16 M HCl (84 +/- 3% extracted after 2 h) indicating a high degree of potential mobility and bioavailability. In contrast, the 2 h extraction of samples contaminated with DU particles originating either from corrosion of unspent DU penetrators or from impacted DU ammunition appeared to be much slower (20-30%) as uranium was less oxidized (+4 to +6). Crystalline phases such as UO(2), UC and metallic U or U-Ti alloy were determined in impacted DU particles from Kosovo and Kuwait, while the UO(2,34) phase, only determined in particles from Kosovo, could reflect a more corrosive environment. Although the results are based on a limited number of DU particles, they indicate that the structure and extractability of DU particles released from similar sources (metallic U penetrators) will depend on the release scenarios (fire, impact) and to some extent environmental conditions. However, most of the DU particles (73-96%) in all investigated samples were dissolved in 0.16 M HCl after one week indicating that a majority of the DU material is bioaccessible