BRCA2与LIM结构域蛋白FHL2的相互作用

目的：应用酵母双杂交方法筛选BRCA2相互作用蛋白编码基因，验证其相互作用并研究其功能联系。方法：以BRCA2基因3′端片段构建酵母双杂交质粒，筛选正常人乳腺上皮细胞cDNA库，获得编码相互作用蛋白的基因，采用免疫共沉淀、哺乳细胞双杂交和荧光酶测定等方法进一步验证蛋白间相互作用和功能联系．结果：采用酵母双杂交系统筛选，获得了多个编码BRCA2相互作用蛋白的基因，其中包括已知的FHL2蛋白；免疫共沉淀和哺乳动物细胞双杂交试验显示BRCA2和FHL2在体内特异性结合，并证实FHL2在体内形成同源二聚体；转录活性分析发现BRCA2与FHL2有协同转录激活作用。结论：发现BRCA2与FHL2蛋白间相互作用和功能联系，为BRCA2功能研究提供了新的方向。     

Restoration of MHC Class I Surface Expression and Endogenous Antigen Presentation by a Molecular Chaperone

Presentation of cytosolic peptides in the context of major histocompatibility complex (MHC) class I antigen is crucial for immune recognition of virus-infected and malignant cells. This process, which is often defective in cancer cells, involves a series of cellular events which may be facilitated by heat shock proteins (molecular chaperones). To address the influence of chaperone function on the presentation of cytosolic peptides, we have utilized B16 melanoma cells (H-2^b). These tumour cells are resistant to lysis by MHC class I-restricted cytotoxic T lymphocytes (CTL), due to a very low level of surface MHC expression. The authors found that stably transfected clones of B16 expressing a heterologous heat shock protein (Hsp65) exhibit significantly increased levels of MHC class I antigens on their surface, and are effectively lysed by alloreactive CTL. These MHC class I molecules can form functional MHC-peptide complexes which are recognized by virus-specific CTL. Moreover, mice immunized with Hsp65-expressing tumour cells, but not with control-transfected tumour cells, display a significantly increased resistance to a subsequent challenge with live, wild-type B16. Together, these results indicate that the suitable expression of a molecular chaperone can overcome a defect in MHC class I expression and antigen presentation, and suggest a novel approach to cancer immunotherapy.     

A NEW METHOD OF MEASURING CARDIAC OUTPUT IN MAN USING LITHIUM DILUTION

We describe a new indicator dilution method of measuring cardiacoutput in man. A bolus injection of lithium chloride 0.6 mmolwas given via a central venous catheter and arterial plasma[Li⁺] recorded using a specially developed sensor incorporatingan Li⁺-selective electrode. Cardiac output was derived fromthe lithium dilution curve, with a correction for packed cellvolume. Lithium dilution cardiac output (LiDCO) was comparedwith thermodilution cardiac output (TD) using 22 lithium sensorsin nine patients. For each sensor, one LiDCO was measured immediatelybefore and one immediately after three TD estimations and meanvalues of LiDCO and TD derived. The correlation coefficient,r, was 0.89; slope of the regression 0.84; Y intercept 0.72;bias 0.3 (0.5) litre min^–1 (mean (TD-LiDCO) (1 SD). LiDCOappeared to be a safe, simple and accurate technique which doesnot require insertion of a pulmonary artery catheter.     

Plasma ionized calcium during open-heart surgery

Plasma ionized calcium has been measured in eighteen patients undergoing open heart surgery. No change in ionized calcium concentration was found during the period of cardiopulmonary bypass. In the early postbypass period, a wide range of ionized calcium concentrations was found, but this did not obviously affect myocardial performance. Factors influencing the ionized calcium concentration under these circumstances are discussed.     

抗BACP1抗体的制备及鉴定

目的: 制备抗BACP1多克隆抗体并鉴定其特异性,用于BACP1蛋白定位及功能研究. 方法: 大肠杆菌表达GST-BACP1融合蛋白,采用纯化蛋白免疫新西兰大白兔制备抗血清. 采用Western Blot和间接免疫荧光染色等方法鉴定抗体的特异性. 结果: 抗BACP1抗体用于Western Blot和间接免疫荧光染色均可特异性识别BACP1蛋白,具有较高的特异性. 结论: 所制备的多克隆抗体具有较高特异性,为进一步分析BRACP1的定位和功能提供了重要工具.     

Postpausal Ventricular Fibrillation Analyzed by Holter-ECG: A Case Report

A 70-year-old male patient with a myocardial infarction, 3 months previously, happened to be wearing a Holter monitor at cardiac arrest during micturition. The patient had ventricular fibrillation (VF) and was successfully resuscitated by means of defibrillation. Analysis of the Holter tape revealed atrial fibrillation and secondary ventricular premature beats (VPB), i.e., VPBs dependent upon a relatively long interval between the two preceding heartbeats. The VF was preceded by an especially long R-R interval (1.45 sec) following a run of especially short R-R intervals implying the sharpest deceleration of the ventricular rate during 1 hour Holter recording preceding the cardiac arrest. A peculiar large alteration of the T wave configuration was also found to precede the VF.