Study on the expression of IkappaB-alpha protein in TNF-alpha induced apoptosis of U937 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the TNF-alpha induced apoptosis of U937 cells, the expression, degradation and subcellular localization of IkappaB-alpha, and its degradation mechanism.</p><p><b>METHOD</b>Changes and subcellular loca-lization of IkappaB-alpha were observed by fluorescence microscopy, expression and degradation of IkappaB-alpha protein with N-tosyl-L-phenylalanylchloromethyl ketone (TPCK protease inhibitor) blocking test and apoptosis of U937 cell by flow cytometry.</p><p><b>RESULTS</b>(1) immunolfluorescence assay showed that IkappaB-alpha localized in cytoplasm only. (2) The level of IkappaB-alpha protein was downregulated after TNF-alpha stimulation, flow cytometry also confirmed the downregulation. (3) The downregulation of IkappaB-alpha protein levels in TNF-alpha induced apoptosis was partially inhibited by TPCK. (4) The apoptosis rate of U937 cells induced by TNF-alpha was (60.73 +/- 1.61)%.</p><p><b>CONCLUSION</b>(1) Degradation of IkappaB-alpha protein during TNF-alpha induced apoptosis of U937 cells suggested the activation of NF-kappaB. (2) TPCK sensitive protease plays an important role in the degradation of IkappaB-alpha protein. (3) TPCK sensitive protease also involved in the apoptosis of U937 cells induced by TNF-alpha.</p>

Cytogenetic Diagnosis of Fanconi's Anemia-Distinguishing Fanconi's Anemia from Aplastic Anemia / 中国实验血液学杂志

Fanconi's anemia (FA) is an autosomal recessive disease featuring a great diversity of clinical symptoms, including congenital malformation, growth retardation and bone marrow failure. Cells obtained from FA patients show a specific hypersensitivity to crosslinking agents such as mitomycin C (MMC). In this study, MMC-induced chromosome breakage tests have been done on 27 healthy controls and 51 patients with bone marrow failure [including 48 patients with aplastic anemia (AA) and 3 patients with FA before cytogenetic analysis]. The results showed that: (1) Diagnosis of 4 FA cases was confirmed, and one of them was the correction of clinical misdiagnosis; bone marrow failure combined with congenital malformation was observed in a few of non-FA aplastic anemia patients, while 1 FA patient lacked congenital abnormality and underdiagnosed before cytogenetic analysis. The data confirmed that misdiagnosis or underdiagnosis of FA could be caused without cytogenetic study. (2) Spontaneous chromosome breakages observed in FA patients were the same as those in AA patients and healthy controls. MMC-induced chromosome breakages observed in FA patient cells were much higher than those in AA patients and healthy controls, especially, metaphases containing more than 5 breakages were easily found in FA lymphocytes treated with 50 ng MMC. (3) Mosaic was found in one of the 4 FA patients. MMC-induced chromosome breakage test at different MMC concentrations could help to dignosis of FA mosaic patient.