967 research outputs found

    Distribution of selenium in the plume of the Gediz River, Izmir Bay, Aegean Sea

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    Selenium (Se) variations in the water column, suspended particulate matter, and sediment through the salinity gradient, together with water-quality parameters, were investigated over four different river conditions: lowest–highest runoff and high–low production period between November 2004 and August 2005 in the plume of the Gediz River, Aegean Sea, Turkey. The drainage basin of the Gediz delta is predominantly agricultural and industrial in character. Dissolved Se exceeded the water-quality standard of 5 μg L–1 during high flow and varied from 9.4 μg L–1 to 0.02 μg L–1 through the salinity gradient during the study period. Particulate Se ranged from 5.2 μg L–1 to 0.02 μg L–1. Sediment in the river mouth was highly affected by Se contamination and reached a level greater than four times (7.6 μg L–1 dry wt) the background level. The results indicated that Se supplied by the river was removed rapidly from the water column before the salinity reached an average value of about 20 and accumulated within the delta

    γδ T cells affect IL-4 production and B-cell tolerance

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    γδ T cells can influence specific antibody responses. Here, we report that mice deficient in individual γδ T-cell subsets have altered levels of serum antibodies, including all major subclasses, sometimes regardless of the presence of αβ T cells. One strain with a partial γδ deficiency that increases IgE antibodies also displayed increases in IL-4–producing T cells (both residual γδ T cells and αβ T cells) and in systemic IL-4 levels. Its B cells expressed IL-4–regulated inhibitory receptors (CD5, CD22, and CD32) at diminished levels, whereas IL-4–inducible IL-4 receptor α and MHCII were increased. They also showed signs of activation and spontaneously formed germinal centers. These mice displayed IgE-dependent features found in hyper-IgE syndrome and developed antichromatin, antinuclear, and anticytoplasmic autoantibodies. In contrast, mice deficient in all γδ T cells had nearly unchanged Ig levels and did not develop autoantibodies. Removing IL-4 abrogated the increases in IgE, antichromatin antibodies, and autoantibodies in the partially γδ-deficient mice. Our data suggest that γδ T cells, controlled by their own cross-talk, affect IL-4 production, B-cell activation, and B-cell tolerance

    Adapting temperature predictions to MR imaging in treatment position to improve simulation-guided hyperthermia for cervical cancer

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    Hyperthermia treatment consists of elevating the temperature of the tumor to increase the effectiveness of radiotherapy and chemotherapy. Hyperthermia treatment planning (HTP) is an important tool to optimize treatment quality using pre-treatment temperature predictions. The accuracy of these predictions depends on modeling uncertainties such as tissue properties and positioning. In this study, we evaluated if HTP accuracy improves when the patient is imaged inside the applicator at the start of treatment. Because perfusion is a major uncertainty source, the importance of accurate treatment position and anatomy was evaluated using different perfusion values. Volunteers were scanned using MR imaging without (&amp;#x201C;planning setup&amp;#x201D;) and with the MR-compatible hyperthermia device (&amp;#x201C;treatment setup&amp;#x201D;). Temperature-based quality indicators were used to assess the differences between the standard, apparent and the optimized hyperthermia dose. We conclude that pre-treatment imaging can improve HTP predictions accuracy but also, that tissue perfusion modelling is crucial if temperature-based optimization is applied.</p
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