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The relationship between methylxanthine intake (caffeine, theobromine and theophylline) and risk of benign proliferative epithelial disorders (BPED) of the breast was examined in a case-control study conducted in Adelaide, South Australia. The study involved 383 cases with biopsy-confirmed BPED, 192 controls whose biopsy did not show epithelial proliferation, and 383 unbiopsied community controls individually matched to cases on age and area of residence. Overall, there was relatively little variation in risk of BPED with total methylxanthine intake, or with intake of caffeine or theophylline, while there was a positive association between theobromine intake and risk of BPED, but only when cases were compared with biopsy controls. Total methylxanthine intake was positively associated with risk of BPED showing severe atypia, but the trend in risk was statistically significant only when community controls formed the comparison group. These data do not provide strong support for an association between methylxanthine intake and risk of BPED. 相似文献
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Normal and diseased isolated lungs: high-resolution CT 总被引:8,自引:0,他引:8
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The adhesion of hematopoietic progenitor cells to bone marrow stromal cells is critical to hematopoiesis and involves multiple effector molecules. Stromal cell molecules that participate in this interaction were sought by analyzing the detergent-soluble membrane proteins of GBI/6 stromal cells that could be adsorbed by intact FDCP-1 progenitor cells. A single-chain protein from GBI/6 cells having an apparent molecular weight of 37 Kd was selectively adsorbed by FDCP-1 cells. This protein, designated p37, could be surface-radiolabeled and thus appeared to be exposed on the cell membrane. An apparently identical 37- Kd protein was expressed by three stromal cell lines, by Swiss 3T3 fibroblastic cells, and by FDCP-1 and FDCP-2 progenitor cells. p37 was selectively adsorbed from membrane lysates by a variety of murine hematopoietic cells, including erythrocytes, but not by human erythrocytes. Binding of p37 to cells was calcium-dependent, and was not affected by inhibitors of the hematopoietic homing receptor or the cell-binding or heparin-binding functions of fibronectin. It is proposed that p37 may be a novel adhesive molecule expressed on the surface of a variety of hematopoietic cells that could participate in both homotypic and heterotypic interactions of stromal and progenitor cells. 相似文献
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Current models hold that CD4+ depletion occurs as a result of direct and indirect effects of HIV, which both kill peripheral
CD4+ cells and prevent adequate regeneration. Although age-associated involution diminishes thymic reserve and HIV is clearly
thymotoxic, clinical trials have nonetheless shown that large proportions of patients who sustain adequate control of viral
replication with highly active antiretroviral therapy (HAART) will demonstrate some evidence for thymic-dependent immune reconstitution,
which is associated with improved immune competence. Furthermore, patients with insufficient or absent immune reconstitution
following HAART generally lack evidence for thymopoiesis. Current studies are focused on improving our understanding of the
causes for thymic failure in HIV infection. Recent work has demonstrated that some HIV strains, especially those that are
CXCR4 trophic, are more thymotoxic and may contribute to irreversible thymic damage in this population. 相似文献