大鼠实验性急性胰腺炎时血浆和组织脂质过氧化物的变化

本文观察了大鼠实验性急性胰腺炎时血浆和组织脂质过氧化物(LPO)的动态变化。发病后10h动物血浆LPO即见升高,而血浆淀粉酶水平则开始下降。发病10、20h心、肝、肾、肺组织LPO也有不同程度的升高。这证实了氧自由基在急性胰腺炎病理过程中起一定作用。与用血清淀粉酶水平判断急性胰腺炎的发生、发展这一传统方法相比,血浆LPO更能反映急性胰腺炎后期病变的程度及此时全身器官组织受损的情况。     

双链断裂修复蛋白hKu70缺陷细胞株的建立及其生物学特性

目的 建立并鉴定DNA双链断裂(DSB)修复蛋白hKu70缺陷细胞株,并观察该缺陷细胞的某些生物学效应,用于AKu70基因功能及职业有害因素对DNA双链断裂修复影响的研究。方法 用构建的AKu70基因反义RNA绿色荧光蛋白真核表达载体(pEGFP—CI—K)转染人胚肺成纤维细胞(HLF),用蛋白兔疫印迹法鉴定转染细胞中AKu70基因的表达水平。同时观察转染细胞生长形态,绘制生长曲线,软琼脂培养法鉴定恶性程度。结果 pEGFP—CI—K载体在转染细胞内可较稳定表达,hKu70蛋白缺陷细胞株AKu70基因的蛋白表达水平下降了42％,转染后hKu70蛋白缺陷细胞生长形态、生长速度无明显变化,软琼脂培养未见细胞集落。结论 成功建立和鉴定了hKu70蛋白缺陷细胞株,该缺陷不足以单独引起可观察的某些生物学效应。     

The sensitivity and specificity of the immediate-spin crossmatch

The immediate-spin (IS) crossmatch is used to detect ABO incompatibility between donor red cells (RBCs) and the serum of the intended recipient. However, this test may be positive in the absence of ABO incompatibility (false positive) or it may be negative when ABO incompatibility exists (false negative). During a 25-month study, the rates of both false-positive and false-negative IS crossmatch results were evaluated, and the sensitivity and specificity of the IS crossmatch were determined. During the study period, 53,656 IS crossmatches were performed for patients without significant RBC antibodies. Fifty-five patients had positive IS crossmatches, and no false-negative reactions were found. In tests of 55 patients with positive IS crossmatches, 77 false-positive and 5 true-positive reactions were noted. The causes of the false-positive reactions were rouleaux (36 patients), cold-reactive antibodies (8 patients), a combination of rouleaux and cold-reactive antibodies (2 patients), fibrin clot (1 patient), and undetermined (3 patients). The sensitivity and specificity of the IS crossmatch were 100 and 99.86 percent, respectively. Laboratory personnel should be aware that the IS crossmatch may have false-positive or false-negative results, and they should develop written protocols to distinguish quickly between true-positive and false-positive reactions.     

Late onset dementia with argyrophilic grains and subcortical tangles or atypical progressive supranuclear palsy?

Most clinically demented elderly patients are found at autopsy to have Alzheimer's disease, multi-infarct dementia, Parkinson's disease, Pick's disease, or Creutzfeldt-Jakob disease. We studied 5 patients clinically characterized by late onset dementia whose brains showed no pathological evidence of Alzheimer's disease, or any other specific neuropathological diagnosis. We found argyrophilic grains, coiled bodies, abundant Alz-50-positive and thioflavine S-negative neurofibrillary tangles, and neuropil threads in the hippocampus, entorhinal cortex, locus ceruleus, substantia nigra, subthalamic nucleus, and inferior olives. Ultrastructurally, the grains, threads, and tangles were composed of straight tubulofilamentous structures, 25 nm in diameter, similar to those found in patients with progressive supranuclear palsy but different from the paired helical filaments of patients with Alzheimer's disease. These findings suggest that the late onset dementia with argyrophilic grains syndrome is also characterized by the presence of tangles and threads with the topographical distribution of progressive supranuclear palsy.     

When should antibody screening tests be done for recently transfused patients?

The American Association of Blood Banks (AABB) requires that blood samples used for pretransfusion testing of recently transfused (or pregnant) patients must be obtained within 3 days of scheduled transfusions. This requirement, which became effective in July 1988, amended Standard G2.000 of the AABB, which previously required that pretransfusion testing must be done on blood samples obtained within 2 days of scheduled transfusions. The present study was designed to estimate the risk associated with adopting the amended version of Standard G2.000. Sixty patients who developed significant unexpected alloantibodies after transfusion were studied retrospectively. Thirteen of the 60 patients were found to have newly detectable antibodies within 83 hours of a sample reported to be negative for the new antibody. Had the amended version of Standard G2.000 been in effect, the detection of some of these antibodies might have been delayed up to 24 hours. It was estimated that the implementation of the new AABB requirement at the authors' institution could potentially place about 1 in 3000 transfused patients at risk for an acute or delayed hemolytic transfusion reaction.     

Survey on pretransfusion testing

BACKGROUND: Hospitals and blood centers throughout the United States use a variety of reagents and methods to perform pretransfusion testing. A survey was developed to determine the reagents and methods in use and their relative prevalence in different work settings. STUDY DESIGN AND METHODS: A national survey on pretransfusion testing was conducted. Surveys were distributed to state and regional blood bank associations, which then distributed them to hospitals and blood centers within their region. In most instances, the blood centers distributed the survey to the local hospitals. Completed surveys were returned to the authors for review, and all information was entered into a database for analysis. RESULTS: Analysis of the data shows that the majority of blood banks use monoclonal reagents for ABO testing and monoclonal-polyclonal blended reagents for Rh testing. The data show that anti-IgG and polyclonal antihuman globulin reagents are used almost equally for antibody screening (detection) tests and that most blood banks use a three-cell antibody-screening test. Slightly more than 50 percent of hospitals use an immediate-spin crossmatch in the absence of unexpected antibodies. CONCLUSION: A number of approved reagents and methods are used by blood bank laboratories for pretransfusion testing. Facility size (number of beds) and type tend to influence the choice of methods and reagents employed. This survey provides an opportunity for blood bank laboratories to compare their current practices with those of their peers.     

通过基因芯片筛选创伤修复差异表达基因

目的通过基因芯片筛选同真皮间充质干细胞相关的创伤修复差异表达基因。方法利用贴壁生长的特性分离大鼠真皮间充质干细胞，用Hpure提取伤口液刺激前后dMSCs和创伤前后大鼠皮肤组织中总RNA。PCR扩增已构建抑制消减杂交差异表达文库中485个克隆的插入片断，送北京博奥制作基因芯片。提取的RNA反转录后分别同芯片杂交，找出在细胞水平和组织水平同时高表达的克隆。将这些克隆测序，进行生物信息学分析。结果分离的大鼠真皮间充质干细胞呈纺锤形，在体外显示多向分化潜能。抽提伤口液刺激前后dMSCs和创伤前后大鼠皮肤组织中总RNA，反转录后和基因芯片杂交，发现可能同创伤愈合相关的13条基因，其中热休克蛋白70（HSP70），基质金属蛋白酶3（MMP3），白细胞蛋白酶抑制因子（SLPI）等可能在创伤愈合中有重要意义。结论抑制消减杂交和基因芯片结合是筛选差异表达基因的一种有效方法。伤口液刺激前后dMSCs中差异表达基因的发现能为从基因水平探讨dMSCs参与创伤愈合的分子机制提供新的研究靶点。     

Effectiveness of a prospective physician self-audit transfusion- monitoring system

BACKGROUND: The purpose of this study was to search for a more effective transfusion-monitoring system than the existing system of retrospective peer review. STUDY DESIGN AND METHODS: This research used a study-control, preintervention and postintervention design, to evaluate the effectiveness of a prospective physician self-audit transfusion-monitoring system that functioned without the direct involvement of transfusion service physicians. This research also evaluated the effectiveness of issuing to physicians a memo with transfusion guidelines. Three process indicators were used to assess physician behavior at various stages of the blood-ordering process: 1) the number of crossmatches ordered per admission, 2) the transfusion-to- crossmatch ratio, and 3) the number of blood units returned to the laboratory after physician self-auditing. The study used two outcome indicators to reflect overall blood utilization: 1) the percentage of patients who received red cell transfusions and 2) the number of blood units transfused per recipient each month. RESULTS: The prospective physician self-audit system implemented at the study hospital did not reverse physician transfusion decisions, and the process of issuing to physicians a memo with transfusion guidelines at the control hospital failed to reduce blood usage. However, a transient reduction in blood utilization was observed at the study hospital. CONCLUSION: The reduction was hypothesized to be due to a Hawthorne effect, in which observed behavior is affected by the subject's awareness of the research study.     

The routine use of Rh-negative reagent red cells for the identification of anti-D and the detection of non-D red cell antibodies

BACKGROUND: Before 1987, fewer than 50 patients per year at the authors' laboratory had a positive antibody detection test due to antepartum Rhesus immunoprophylaxis. However, after 1987, a marked increase was observed in the number of patients who had received Rh immune globulin (RhIG) during pregnancy as part of routine antepartum Rh immunoprophylaxis. In anticipation that an increased use of RhIG during pregnancy would increase the number of patients in whom anti-D was detected by this laboratory, a protocol was developed to abbreviate the process required to identify anti-D. Although this protocol was adopted primarily to address an anticipated increase in antenatal RhIG usage in women, it was also applied to alloimmunized Rh-negative males. STUDY DESIGN AND METHODS: When an Rh-negative patient (male or female) had a reactive screening test for unexpected antibodies and met certain other criteria, the patient's serum was tested with a three-vial set of Rh-negative reagent red cells (Rh-negative screening RBCs), instead of with panels of typed RBCs (panel RBCs), for the identification of anti- D or the detection of non-D antibodies. If the serum under test did not agglutinate or hemolyze Rh-negative screening RBCs, anti-D was identified and no further testing was performed. If the serum agglutinated or hemolyzed Rh-negative screening RBCs, conventional testing with panel RBCs was done to determine the antibody specificity. RESULTS: Rh-negative patients (n = 1174) who had reactive screening tests for unexpected antibodies were tested with Rh-negative screening RBCs; 1079 were found to have anti-D as a single antibody. Seven of these patients subsequently developed a non-D alloantibody, after transfusion or pregnancy, and one patient had anti-C that escaped detection at the time of initial testing with Rh-negative RBCs (a false- negative result). Ninety-two patients had anti-D in combination with a non-D antibody, and three patients had a non-D antibody but not anti-D. Use of the anti-D identification protocol actually reduced the laboratory workload by 176 College of American Pathologists workload units per month, in spite of a marked increase in the number of patients in whom anti-D was detected. No hemolytic transfusion reaction was attributed to the abbreviation of anti-D identification. CONCLUSION: The identification of anti-D may be abbreviated without jeopardizing patient safety. Such a protocol can reduce laboratory workload and might be particularly appealing to health care facilities that perform antibody detection testing on large numbers of Rh-negative pregnant women, especially if antepartum RhIG is administered routinely.