Arsenic contamination of Bangladesh aquifers exacerbated by clay layers.

Confining clay layers typically protect groundwater aquifers against downward intrusion of contaminants. In the context of groundwater arsenic in Bangladesh, we challenge this notion here by showing that organic carbon drawn from a clay layer into a low-arsenic pre-Holocene (>12 kyr-old) aquifer promotes the reductive dissolution of iron oxides and the release of arsenic. The finding explains a steady rise in arsenic concentrations in a pre-Holocene aquifer below such a clay layer and the repeated failure of a structurally sound community well.

Reversible adsorption and flushing of arsenic in a shallow, Holocene aquifer of Bangladesh.

The spatial heterogeneity of dissolved arsenic (As) concentrations in shallow groundwater of the Bengal Basin has been attributed to transport of As (and reactive carbon) from external sources or to the release of As from within grey sand formations. We explore the latter scenario in this detailed hydrological and geochemical study along a 300 m transect of a shallow aquifer extending from a groundwater recharge area within a sandy channel bar to its discharge into a nearby stream. Within the 10-20 m depth range, groundwater ages along the transect determined by the H-He method increase from <10 yr in the recharge area to a maximum of 40 yr towards the stream.

CONCOMITANT INJURIES OF ANTERIOR CRUCIATE LIGAMENT AND MENISCUS.

Introduction: The aim of this study was to determine the correlation between meniscal injuries with injuries of the anterior cruciate ligament, as well as risk factors for those associated injuries.

Material And Methods: This study included 496 operated patients. Almost half of patients with meniscal injury were between the ages of 2l and 30 years.

Mucosal adjuvant activity of cholera toxin requires Th17 cells and protects against inhalation anthrax.

Cholera toxin (CT) elicits a mucosal immune response in mice when used as a vaccine adjuvant. The mechanisms by which CT exerts its adjuvant effects are incompletely understood. We show that protection against inhalation anthrax by an irradiated spore vaccine depends on CT-mediated induction of IL-17-producing CD4 Th17 cells.

Dendritic cell activating peptides induce distinct cytokine profiles.

High-mobility group box 1 protein (HMGB1), a DNA-binding nuclear and cytosolic protein, is a pro-inflammatory cytokine released by monocytes and macrophages. HMGB1 as well as its B box domain induce maturation of human dendritic cells (DCs). This report demonstrates that the B box domain induces phenotypic maturation of murine bone marrow-derived dendritic cells (BM-DCs) as evidenced by increased CD86, CD40 and MHC-II expression.

Vaccination with irradiated Listeria induces protective T cell immunity.

We evaluated gamma-irradiated Listeria monocytogenes as a killed bacterial vaccine, testing the hypothesis that irradiation preserves antigenic and adjuvant structures destroyed by traditional heat or chemical inactivation. Irradiated Listeria monocytogenes (LM), unlike heat-killed LM, efficiently activated dendritic cells via Toll-like receptors and induced protective T cell responses in mice. Like live LM, irradiated LM induced Toll-like-receptor-independent T cell priming.