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111.
The inappropriate expression of c-myc in cells deprived of growth factors has recently been implicated in the activation of programmed cell death (apoptosis). The studies described here examine the ability of interleukin-3 (IL-3) or erythropoietin (Epo) to suppress apoptosis that occurs in association with enforced myc expression during cell cycle arrest of a murine IL-3-dependent myeloid progenitor cell line, 32D. G1 arrest was observed when culturing 32D cells to high density in medium supplemented with IL-3, or at subconfluent densities in medium supplemented with Epo. Under both conditions, endogenous c-myc expression was downregulated and viability was maintained. In clones of cells in which c-myc is constitutively expressed from a retroviral vector, enforced c-myc expression was associated with the activation of apoptosis at high cell densities. Similarly, enforced c-myc expression was deleterious to cell survival when these cells were cultured in Epo, as apoptosis was evident within 6 hours. The results support the concept that inappropriate c-myc expression activates apoptosis and that neither IL-3 nor Epo can suppress this program under these conditions. 相似文献
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Masking generates contiguous segments of metal-coated and bare DNA for scanning tunneling microscope imaging. 总被引:3,自引:1,他引:2
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D D Dunlap R García E Schabtach C Bustamante 《Proceedings of the National Academy of Sciences of the United States of America》1993,90(16):7652-7655
To date, no microscopic methods are available to confirm scanning tunneling microscope (STM) images of DNA. The difficulties encountered in repeating these images may be attributed to inadequate distribution of molecules on the substrate, poor adhesion to the substrate, or the low conductivity of the molecules. However, these factors are difficult to assess in an STM experiment where they may act simultaneously. A method to isolate these factors involves partly masking the deposited molecules before coating them with a conductive film to produce adjacent segments of coated and bare DNA after the mask is removed. The coated DNA segments are conductive and mechanically stable to allow easy identification of DNA by the STM. Furthermore, the path of a molecule can be traced from a coated to an uncoated region to test STM imaging of bare DNA. Masked preparations of DNA deposited on platinum/carbon-coated mica and highly oriented pyrolytic graphite were examined with a tunneling current 1000 times lower than the usual nanoamps. The tip apparently displaces molecules adsorbed to graphite to preclude imaging whereas more stably bound DNA on platinum/carbon-coated mica appears in reversed contrast. 相似文献
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Michelle C Montpetit Jamile L Shammo Jerome Loew Stephanie Dunlap Salpy V Pamboukian Alain Heroux 《The Journal of heart and lung transplantation》2004,23(9):1119-1122
An acquired form of sideroblastic anemia has been described in association with several drugs, especially anti-microbial agents. A case of sideroblastic anemia is presented in a patient with a left ventricular assist device drive-line infection who was receiving linezolid, an antibiotic used for serious infections with gram-positive organisms. This patient's anemia resolved after discontinuation of the drug; he subsequently underwent an uncomplicated orthotopic heart transplant with no recurrence of anemia. As linezolid has been shown to have hematologic side effects, blood count monitoring is recommended in patients receiving this drug for long-term therapy. 相似文献
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This article describes a quality assurance program for monitoring and decreasing venipuncture complications after contrast media injection. The authors share the experience at their facility, where the program was created and used successfully. 相似文献
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In a preterm infant, chest tubes were inserted for treatment of bilateral pneumothoraces. Hemorrhagic pericardial effusion with cardiac tamponade developed, probably resulting from traumatic injury by the left chest tube. The infant survived due to timely diagnostic and therapeutic intervention. No recurrence of pericardial effusion was seen and follow-up showed normal psychomotor development. 相似文献