The impact of human herpesvirus 6B reactivation on early complications following allogeneic hematopoietic stem cell transplantation.

Although human herpesvirus 6 (HHV-6) has been considered an important opportunistic and potentially fatal pathogen for allogeneic hematopoietic stem cell transplantation (HSCT), the clinical significance of HHV-6 reactivation remains controversial. In this study, we monitored HHV-6 DNAemia in 72 consecutive allogeneic HSCT recipients by real-time quantitative polymerase chain reaction. A total of 680 peripheral blood specimens were collected from the recipients before HSCT or at weekly intervals after HSCT. As the predominant variant, HHV-6B was detectable at least once in 47.2% (34/72) of HSCT recipients on the median day 21 (range, 7-84 days); HHV-6A reactivation occurred in only 1 recipient (1.4%). Detectable HHV-6B reactivation was associated with increased probability of skin rash by day 30 after HSCT (hazard ratio [HR], 3.68; 95% confidence interval [CI], 1.24-10.92; P = .019), cytomegalovirus (CMV) antigenemia (HR, 2.35; 95%CI, 1.32-4.19; P = .004), and hemorrhagic cystitis (HC) (HR, 2.59; 95%CI, 0.96-6.98; P = .061) by day 100 after HSCT. Neutrophil and platelet engraftment, mortality for 100 days after HSCT were not affected by HHV-6B reactivation. In conclusion, HHV-6 reactivation is a common event, and this study demonstrates a correlation between HHV-6B infection and CMV reactivation, early rash, and possibly increased incidence of HC after transplantation.     

一种双计算机互联的视觉诱发电位采集系统

本文研制了一种采用二台计算机互联方法实现的诱发电位采集系统，该系统将刺激图形的产生和数据采集分别由两台计算机来完成，通过一些附加的处理保证了模式“给”“撤”光与数据采集的同步，实验结果与目前通用的诱发电位仪的结果基本一致，但比一般的诱发电位仪具有更丰富更灵活的刺激图形方式，本系统为深入研究ＶＥＰ提供了一个价廉、方便、灵活的实验系统。     

微机心电场仿真模型与仿真研究

心电场仿真是心电理论研究的前沿课题。本文讨论首次在IBM-PC/AT微机上实现的一个完整的心电场仿真模型。其中,人体和心脏的单元分割精度与国外最近的研究相同,采用边界元法求解心电场电位,并提出一种新的心脏兴奋传播仿真算法,提高了仿真速度。应用该模型对正常心脏和病变心脏进行了仿真研究,仿真结果与临床测量结果是一致的。     

Mutations in the genome of porcine reproductive and respiratory syndrome virus responsible for the attenuation phenotype

Summary.  Although live-attenuated vaccines have been used for some time to control clinical symptoms of the porcine reproductive and respiratory syndrome (PRRS), the molecular bases for the attenuated phenotype remain unclear. We had previously determined the genomic sequence of the pathogenic PRRSV 16244B. Limited comparisons of the structural protein coding sequence of an attenuated vaccine strain have shown 98% homology to the pathogenic 16244B. Here we have confirmed the attenuated phenotype and determined the genomic sequence of that attenuated PRRSV vaccine and compared it to its parental VR-2332 and the 16244B strains. The attenuated vaccine sequence was colinear with that of the strain 16244B sequence containing no gaps and 212 substitutions over 15,374 determined nucleotide sequence. We identified nine amino acid changes distributed in Nsp1β, Nsp2, Nsp10, ORF2, ORF3, ORF5 and ORF6. These changes may provide the molecular bases for the observed attenuated phenotype. Received August 28, 1999 Accepted December 16, 1999     

精氨酸加压素对实验性神经细胞老化过程中细胞周期和细胞总蛋白的影响

采用小鼠神经母细胞瘤细胞无血清培养，建立神经细胞老化实验研究模型。以流式细胞光度术观察精氨酸加压素（ＡＶＰ）对老化过程中实验性神经细胞的细胞周期和细胞总蛋白的影响。结果发现ＡＶＰ可产生延缓细胞老化的细胞周期和细胞总蛋白的变化。提示ＡＶＰ通过使细胞周期、ＤＮＡ和细胞总蛋白等发生变化来发挥其延缓实验性神经细胞老化的作用。     

黑质的定态与定位研究

本文调查了41只整脑82个黑质的空间形态和位置。在三维切面上作2毫米厚的连续切片,获得资料:黑质的长径、宽径、高径;体积及“靶心”坐标值;通过还原、重建,绘出空间投影轮廓图;黑质为前后偏长、左右窄扁的薄片状灰质块,在脑内空间的整体构型是呈后倾倒内上斜外偏转态。     

医学影像数据库的索引及检索技术的研究

随着医学影像数据库数据量的剧增，迫切需要研究高效的索引技术以支持基于图像内容的检索。介绍了医学影像数据库索引技术的特点，比较分析了几种典型的空间数据索引方法（如R树、VA文件、A树、NB树和M树）及其作为医学图像数据库索引的性能。     

The major T cell epitope on type II collagen is glycosylated in normal cartilage but modified by arthritis in both rats and humans

Type II collagen (CII) is a target for autoreactive T cells in both rheumatoid arthritis and the murine model collagen-induced arthritis. The determinant core of CII has been identified as CII260-270, and the alteration of this T cell epitope by posttranslational modifications is known to be critical for development of arthritis in mice. Using CII-specific T cell hybridomas we have now shown that the immunodominant T cell epitope in the normal (healthy) human and rat joint cartilage is O-glycosylated at the critical T cell receptor recognition position 264 with a mono- or di-saccharide attached to a hydroxylysine. In contrast, in the arthritic human and rat joint cartilage there are both glycosylated and non-glycosylated CII forms. Glycosylated CII from normal cartilage could not be recognized by T cells reactive to peptides having only lysine or hydroxylysine at position 264, showing that antigen-presenting cells could not degrade the O-linked carbohydrate. Thus, the variable forms of the glycosylated epitope are determined by the structures present in cartilage, and these vary during the disease course. We conclude that the chondrocyte determines the structures presented to the immune system and that these structures are different in normal versus arthritic states.     

外周动脉腔内超声显像的形态学研究

血管内超声是利用安装在心导管顶端的微型超声探头从管腔内观察血管形态学的新技术，为了解其对人体动脉实时显像的能力及定量定性的准确性，在自行设计的实验模型装置上的对９段经生理压力固定的人离体外周动脉进行超声显像，然后将血管组织对应切片观察，对比二者结果发现：（１）血管内超声可准确测定动脉腔面积，周长，直径和厚度等重要参数，与组织学测值相关系数均在０．９５以上（Ｐ〈０．００１）；（２）肌性和弹性动脉组织