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  • Author or Editor: H. A. Schreiber x
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Application of INAA and XRFA in a comparative environmental study
Authors: V. Cercasov, A. Pantelica, M. Salagean and H. Schreiber

Abstract  

Environmental monitoring requires reliable and effective analytical techniques for widely different concentration ranges. Two such methods (INAA and XRFA) were applied in a comparative environmental study on air dust filters and grass. The samples were collected during one year at two locations (near Bucharest/Romania and near Stuttgart/Germany) with different levels of air pollution. Seventeen environmentally relevant elements (As, Ba, Br, Ca, Co, Cr, Cu, Fe, K, Mn, Ni, Pb, S, Sb, Se, V, Zn) were determined. The aim was to test the suitability of INAA and XRFA methods for different elements in these kinds of samplesaat realistical pollution levels. The results were statistically compared for 13 elements, which were determined by both analytical techniques. They were also used to characterize the air pollution level and its variation at the two locations, and to compare them. Generally, concentrations in air of the elements studied are higher in Bucharest than in Stuttgart.

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Continuous repopulation of lymphocyte subsets in transplanted mycobacterial granulomas
Authors: H. A. Schreiber, J. S. Harding, C. J. Altamirano, O. Hunt, P. D. Hulseberg, Zs. Fabry and Matyas Sandor

Abstract

Granulomas are the interface between host and mycobacteria, and are crucial for the surivival of both species. While macrophages are the main cellular component of these lesions, different lymphocyte subpopulations within the lesions also play important roles. Lymphocytes are continuously recruited into these inflammatory lesions via local vessels to replace cells that are either dying or leaving; however, their rate of replacement is not known. Using a model of granuloma transplantation and fluorescently labeled cellular compartments we report that, depending on the subpopulation, 10–80%, of cells in the granuloma are replaced within one week after transplantation. CD4+ T cells specific for Mycobacterium antigen entered transplanted granulomas at a higher frequency than Foxp3+ CD4+ T cells by one week. Interestingly, a small number of T lymphocytes migrated out of the granuloma to secondary lymphoid organs. The mechanisms that define the differences in recruitment and efflux behind each subpopulation requires further studies. Ultimately, a better understanding of lymphoid traffic may provide new ways to modulate, regulate, and treat granulomatous diseases.

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