Life charts on a palmtop computer: first results of a feasibility study with an electronic diary for bipolar patients

Schärer LO, Hartweg V, Valerius G, Graf M, Hoern M, Biedermann C,Walser S, Boensch A, Dittmann S, Forsthoff A, Hummel B, Grunze H, Walden J. Life charts on a palmtop computer: first results of a feasibility study with an electronic diary for bipolar patients. Bipolar Disord 2002: 4(Suppl. 1): 107–108. © Blackwell Munksgaard, 2002     

转录因子T-bet与哮喘大鼠气道炎症及川芎嗪的干预效应

目的:转录因子T-bet在支气管哮喘的发病中起重要作用,川芎嗪治疗哮喘有效。实验拟观察川芎嗪对哮喘大鼠气道炎症的影响和转录因子T-bet的调控作用。方法:实验于2005-11/2006-06在南京医科大学完成。①实验材料及分组:72只SPF级SD大鼠随机分为正常对照组、哮喘模型组、川芎嗪小剂量组(20mg/kg)、川芎嗪中剂量组(40mg/kg)、川芎嗪大剂量组(80mg/kg)和地塞米松组,每组12只。实验用磷酸川芎嗪注射液为丽珠集团利民制药厂生产)。②实验过程及评估:以卵蛋白腹腔注射并雾化吸入制备大鼠哮喘模型,末次雾化后24h内麻醉后处死大鼠。观察6组大鼠肺组织形态学变化;测定支气管壁厚度、支气管平滑肌厚度、嗜酸粒细胞和淋巴细胞数。采用免疫组织化学半定量法测定肺组织T-bet蛋白的表达;进行转录因子T-bet蛋白表达量与气道炎症的相关性分析。实验过程中对动物处置符合动物伦理学标准。结果:①哮喘模型组嗜酸粒细胞、淋巴细胞、支气管壁厚度和支气管平滑肌厚度,明显高于正常对照组相应指标(P均<0.01);与哮喘模型组比较,川芎嗪小、中、大剂量组和地塞米松组上述4项指标均减少(P均<0.01)。②哮喘模型组、川芎嗪小、中、大剂量组和地塞米松组的T-bet表达量低于正常对照组(P均<0.01);与哮喘模型组比较,川芎嗪小、中、大剂量组T-bet表达量增加(P均<0.01);随着川芎嗪剂量增加,T-bet表达量亦相应增加,川芎嗪小、中、大剂量组之间两两比较,差异均有统计学意义(P均<0.01)。③相关分析显示哮喘模型组T-bet蛋白表达量与嗜酸性粒细胞和淋巴细胞浸润数呈负相关(r=-0.81,-0.85,P<0.01),与支气管管壁厚度和支气管平滑肌厚度呈负相关(r=-0.77,-0.79,P<0.01)。结论:支气管哮喘大鼠存在T-bet低表达;川芎嗪可抑制气道炎症,增加转录因子T-bet蛋白的表达,纠正Th1/Th2失衡,从而治疗支气管哮喘。     

Adherence of L1210 murine leukemia cells to sephacryl- aminopropylcobalamin beads treated with transcobalamin-II

Sephacryl beads containing an immobilized aminopropylcobalamin- transcobalamin-II complex serve as foci for the adherence of L1210 murine leukemia cells. Bead-cell interaction does not occur when (A) nonderivatized beads are used; (B) transcobalamin-II is omitted or presaturated with cyanocobalamin in the preparation of the bead complex; (C) intrinsic factor replaces transcobalamin-II; and (D) the complex is removed from beads by photolysis. These observations suggest that adherence results from the ability of transcobalamin-II to form a bridge between immobilized cobalamin on the bead and receptors in the plasma membrane of the cell.     

CHK2–BRCA1 tumor-suppressor axis restrains oncogenic Aurora-A kinase to ensure proper mitotic microtubule assembly

BRCA1 (breast cancer type 1 susceptibility protein) is a multifunctional tumor suppressor involved in DNA damage response, DNA repair, chromatin regulation, and mitotic chromosome segregation. Although the nuclear functions of BRCA1 have been investigated in detail, its role during mitosis is little understood. It is clear, however, that loss of BRCA1 in human cancer cells leads to chromosomal instability (CIN), which is defined as a perpetual gain or loss of whole chromosomes during mitosis. Moreover, our recent work has revealed that the mitotic function of BRCA1 depends on its phosphorylation by the tumor-suppressor kinase Chk2 (checkpoint kinase 2) and that this regulation is required to ensure normal microtubule plus end assembly rates within mitotic spindles. Intriguingly, loss of the positive regulation of BRCA1 leads to increased oncogenic Aurora-A activity, which acts as a mediator for abnormal mitotic microtubule assembly resulting in chromosome missegregation and CIN. However, how the CHK2–BRCA1 tumor suppressor axis restrains oncogenic Aurora-A during mitosis to ensure karyotype stability remained an open question. Here we uncover a dual molecular mechanism by which the CHK2–BRCA1 axis restrains oncogenic Aurora-A activity during mitosis and identify BRCA1 itself as a target for Aurora-A relevant for CIN. In fact, Chk2-mediated phosphorylation of BRCA1 is required to recruit the PP6C–SAPS3 phosphatase, which acts as a T-loop phosphatase inhibiting Aurora-A bound to BRCA1. Consequently, loss of CHK2 or PP6C-SAPS3 promotes Aurora-A activity associated with BRCA1 in mitosis. Aurora-A, in turn, then phosphorylates BRCA1 itself, thereby inhibiting the mitotic function of BRCA1 and promoting mitotic microtubule assembly, chromosome missegregation, and CIN.Breast cancer type 1 susceptibility protein (BRCA1) is a major and multifunctional tumor-suppressor protein involved in the regulation of chromatin organization, gene expression, DNA damage response, and DNA repair (1–3). In addition to its functions in interphase, BRCA1 also is required for faithful execution of mitosis. Consequently, loss of BRCA1 results in abnormal mitotic progression, chromosome missegregation, and chromosomal instability (CIN), hallmark phenotypes of human cancer (4–6). However, the mitotic function of BRCA1 and its regulation during mitosis is little understood. BRCA1 localizes to centrosomes throughout the cell cycle and is phosphorylated during mitosis on S988 by the checkpoint kinase 2 (Chk2). This positive regulation is essential to ensure proper mitotic spindle assembly and chromosomal stability (5, 7, 8). Importantly, we recently have found that the loss of CHK2 or of Chk2-mediated phosphorylation on BRCA1 causes an increase in microtubule plus-end assembly rates, which results in transient spindle geometry defects facilitating the generation of erroneous microtubule–kinetochore attachments. These defects finally lead to chromosome missegregation and the induction of aneuploidy, thus constituting CIN (6).Interestingly, BRCA1 associates with the Aurora-A kinase during mitosis (6). Aurora-A is a key mitotic kinase encoded by the AURKA oncogene and is involved in various functions during mitosis, including centrosome separation and spindle assembly (9, 10). Aurora-A activation occurs at mitotic centrosomes and requires its autophosphorylation within the T-loop at threonine-288. Subsequent inactivation of Aurora-A can be mediated by the serine/threonine protein phosphatase 6 (PP6), which acts as the T-loop phosphatase for Aurora-A, and involves the catalytic subunit (PP6C) as well as regulatory subunits referred to as “Sit4-associated proteins” (SAPS1-3) and ankyrin repeat proteins (11–13). Significantly, in human cancer, AURKA frequently is overexpressed, and increased activity of AURKA is sufficient to induce enhanced microtubule plus end assembly rates, chromosome missegregation, and CIN (6). Thus, overexpression of AURKA and loss of the CHK2–BRCA1 axis result in the same mitotic abnormalities triggering CIN. Moreover, loss of the Chk2-mediated phosphorylation of BRCA1 causes an increase in BRCA1-bound Aurora-A kinase activity at mitotic centrosomes, which mediates the induction of abnormal microtubule plus end dynamics and CIN (6). However, the molecular mechanism by which the loss of the CHK2–BRCA1 tumor-suppressor axis unleashes oncogenic Aurora-A activity during mitosis and the mitotic target for Aurora-A relevant for the induction of increased microtubule dynamics and CIN remain unknown.     

Characterization of the human neutrophil C1q receptor and functional effects of free ligand on activated neutrophils

The partial characterization and expression of the C1q receptor (C1q-R) in relation to other complement receptors present on the surface of neutrophils has been examined, as well as the effects of free C1q on cell function. A polyclonal anti-C1q-R antibody recognizes a 68-kD neutrophil surface protein. C1q-R expression was not upregulated upon warming, priming, or exposure to FMLP, but decreased after exposure to phorbol myristate acetate (PMA), because of shedding of the receptor into the extracellular medium, as detected by enzyme-linked immunosorbent assay. CR3 and CR1 expression was upregulated from intracellular pools after cell stimulation by PMA. No evidence of intracellular pools of C1q-R was found, as assessed by immunoblotting of subcellular fractions. But C1q-R appeared to be expressed early in cell differentiation, was detected on undifferentiated HL-60 cells, and like CR3 expression, increased upon 5 days differentiation towards a neutrophil lineage. However, C1q-R expression decreased upon additional culture, whereas CR3 expression continued to increase. A large variation in the percentage of peripheral cells expressing C1q receptors in donors was observed, ranging from 13% to 100%, contrasting with CR3 receptors that exhibited less variability. Interactions between free monomeric C1q and neutrophils were also studied. Incubation of stimulated neutrophils with 10 to 100 micrograms/mL C1q resulted in a further increase in CR3 expression and adherence to albumin-coated surfaces. Staphylococci opsonized with low quantities of C1q (0.1 to 1 microgram/mL) mediated a moderate and sustained respiratory burst in neutrophils, whereas a burst of similar magnitude was generated only with free C1q at concentrations 10- to 100-fold higher. Stimulation was only partially inhibited if cells were first treated with anti-C1q-R antibody, suggesting other C1q binding proteins may be present on the cell surface. In summary, neutrophil C1q receptor is approximately 68-kD, exhibits varying expression on different subjects, and is not upregulated from intracellular stores on exposure to soluble stimuli. Stimulated, but not resting, neutrophils selectively respond to raised levels of free C1q, resulting in altered cell function and enhanced CR3 receptor expression. These studies thus suggest complex roles for C1q in neutrophil function.