基于T1W1+C的影像建立支持向量机预测模型对胶质瘤细胞增殖活性研究

目的：基于胶质瘤增强T1加权成像（enhancement T1-weighted image,T1WI+C）影像组学特征进行机器学习,构建预测胶质瘤细胞增殖活性的Ki67指数预测模型。方法：回顾性分析本院手术病理结果为胶质瘤并经免疫组化测定Ki67指数的患者113例,随机按约8∶2拆分为训练集与测试集。通过MRIcroGL软件手绘胶质瘤感兴趣区域（region of interest,ROI）,利用Python中pyradiomics模块获得1 338个影像特征,通过t检验与最小绝对收缩和选择算子（least absolute shrinkage and selection operator,Lasso）回归算法筛选最佳影像组学特征,基于最佳特征使用支持向量机（support vector machine,SVM）分类器建立Ki67预测模型,利用受试者操作特征曲线（receiver operating characteristic curve,ROC曲线）与模型校准曲线评估模型的预测效能。结果：每例患者T1WI+C图像提取1 338个影像组学特征,降维后筛选出6个与胶质瘤Ki67指数密...     

The essential role of stimulus temporal patterning in enabling perceptual learning

Little is known about how temporal stimulus factors influence perceptual learning. Here we demonstrate an essential role of stimulus temporal patterning in enabling perceptual learning by showing that 'unlearnable' contrast and motion-direction discrimination (resulting from random interleaving of stimuli) can be readily learned when stimuli are practiced in a fixed temporal pattern. This temporal patterning does not facilitate learning by reducing stimulus uncertainty; further, learning enabled by temporal patterning can later generalize to randomly presented stimuli.     

The calpain system

The calpain system originally comprised three molecules: two Ca2+-dependent proteases, mu-calpain and m-calpain, and a third polypeptide, calpastatin, whose only known function is to inhibit the two calpains. Both mu- and m-calpain are heterodimers containing an identical 28-kDa subunit and an 80-kDa subunit that shares 55-65% sequence homology between the two proteases. The crystallographic structure of m-calpain reveals six "domains" in the 80-kDa subunit: 1). a 19-amino acid NH2-terminal sequence; 2). and 3). two domains that constitute the active site, IIa and IIb; 4). domain III; 5). an 18-amino acid extended sequence linking domain III to domain IV; and 6). domain IV, which resembles the penta EF-hand family of polypeptides. The single calpastatin gene can produce eight or more calpastatin polypeptides ranging from 17 to 85 kDa by use of different promoters and alternative splicing events. The physiological significance of these different calpastatins is unclear, although all bind to three different places on the calpain molecule; binding to at least two of the sites is Ca2+ dependent. Since 1989, cDNA cloning has identified 12 additional mRNAs in mammals that encode polypeptides homologous to domains IIa and IIb of the 80-kDa subunit of mu- and m-calpain, and calpain-like mRNAs have been identified in other organisms. The molecules encoded by these mRNAs have not been isolated, so little is known about their properties. How calpain activity is regulated in cells is still unclear, but the calpains ostensibly participate in a variety of cellular processes including remodeling of cytoskeletal/membrane attachments, different signal transduction pathways, and apoptosis. Deregulated calpain activity following loss of Ca2+ homeostasis results in tissue damage in response to events such as myocardial infarcts, stroke, and brain trauma.     

32例再生障碍性贫血的微循环及血液粘度

对３２例再障患者的甲襞、球结膜微循环及血粘度进行观察，结果表明：再障组均有不同程度的微循环异常改变（１００％），与正常对照组比较差异显著（Ｐ＜０．０１）；再障组全血粘度、全血还原粘度明显低于正常对照组（Ｐ＜０．０１），再障患者的Ｈｂ与全血粘度及血浆比粘度呈正相关。     

用电子自旋共振成像观测氮氧自由基的透皮特性

在自行研制的电子自旋共振成像(Electron spin resonance imaging, ESRI)系统上建立了活体皮肤电子自旋共振成像的实验模型.观测了氮氧自由基化合物2,2,6,6-四甲基哌啶-1-氧(2,2,6,6-tetramethyl-1-piperidinyloxy,TEMPO)穿透小鼠皮肤组织的动态过程和浓度分布情况.成像结果显示TEMPO化合物对不同方法处理后的皮肤组织的透皮特性有明显差别.TEMPO水溶液难以穿透皮肤,而溶解在二甲基亚枫(Dimethyl sulfoxide,DMSO)中的脂溶性TEMPO溶液可以渗入并穿透皮肤.皮肤表层的角质蛋白对TEMPO有明显的阻隔性, 而且化合物渗入或透过皮肤组织的量具有较强的时间依赖性.本研究结果提示ESRI技术为动态研究某些特殊结构化合物的透皮特性提供了科学有效的分析手段.     

Nucleolar localization of non-structural protein 3b, a protein specifically encoded by the severe acute respiratory syndrome coronavirus

The open reading frame 3 (ORF3) of the severe acute respiratory syndrome coronavirus (SARS-CoV) genome encodes a predicted 154-amino acid protein, which lacks similarities to any known protein, and is named 3b. In this study, it was shown that 3b protein was predominately localized to nucleus with EGFP tag at its N- or C-terminus. The localization patterns were similar in different transfected cells. Immuno-fluorescence assay revealed that 3b protein was co-localized well with C23 in nucleolus. C23, B23 and fibrillarin all are important nucleolar proteins, which localize in the region of the nucleolus. Co-transfection of p3b-EGFP with pC23-DsRed, pB23-DsRed and pfibrillarin-DsRed further confirmed 3b's nucleolus localization. With construction of serial truncated mutants of 3b, a region (residues 134-154 aa) responsible for nucleolar localization was determinated in 3b protein. These results provide a new insight for further functional studies of SARS-CoV 3b protein.     

恒河猴骨髓间充质干细胞分离培养及其生长特性

采用密度梯度离心和贴壁筛选方法分离纯化了恒河猴骨髓间充质干细胞(mesenchymal stem cells from bone marrow of Rhesus monkey,RhBMSCs);通过表面抗原检测和核型分析对细胞进行了初步鉴定;通过生长曲线的绘制和细胞凋亡的检测探讨了细胞的生长特点。本实验获得的RhBMSCs形态以梭型为主,核型正常,CD29表达率为99.2%,CD34、CD45、HLA-DR表达率均低于3.2%,RhBMSCs表型符合间充质干细胞的特点,且纯度较高,细胞生长旺盛,但倍增时间有随传代数的增加而逐渐延长的趋势。本实验探讨了RhBMSCs的体外分离、扩增培养及鉴定的方法,并对其生长特点进行了初步观察,这不仅有助于进一步了解与之近似的人的骨髓间充质干细胞的相关特性,而且为以猕猴为对象的BMSC定向分化和组织修复等动物体内实验打下了基础。     

肿瘤抑制基因变异的分子病理学研究进展

肿瘤分子生物学研究已经证实,肿瘤是一种基因病,是由多基因变异并长期累积所致,其中肿瘤抑制基因（TSG）在肿瘤发生过程中持续丧失功能被认为是导致细胞恶变的最重要事件之一。TSG变异的最常见分子机制是因其2个位点相继因点突变和杂合性缺失（LOH）而导致功能完全失活,即广为接受的Knudsen“二次打击”理论。另一个受到高度重视的基因变异类型是DNA错配修复基因（mismatch repair,MMR)功能的失活,其分子特征是基因组DNA微卫星小体不稳定性（microsatellite instability,MSI)。这两种基因变异形式最终都将导致细胞分裂和增殖活动脱离还调控而发生肿瘤。由于LOH和MSI是肿瘤细胞的重要标志性特征,并具有分子病理学上的诊断意义而受到广泛关注。     

抗蓖麻毒素A链人源化单域抗体的设计、原核表达及生物活性检测

目的 运用计算机辅助蛋白质分子设计的方法设计针对蓖麻毒素A链(RTA)的拮抗肽,实现在大肠杆菌B121中的可溶性表达,并对其生物学活性进行评价.方法 根据RTA的晶体结构、RTA-rRNA相互作用复合物模型,在CVFF(consistent-valence force field)、Amber力场下,对RTA的空间构象进行理论模拟,初步确定其生物活性功能域;然后针对该功能域设计小分子拮抗肽,并借助人抗体重链町变区骨架,在CDR3区对拮抗肽进行展示,用重叠延伸PCR全基因合成人源化的单域抗体并克隆至载体pET-32a(+);双酶切和DNA测序技术对构建的载体进行鉴定;IPrG诱导人源化的单域抗体表达,用镍离子亲和层析纯化,竞争ELISA和MTT法分别进行结合和中和活性检测.结果 从头搭建并设计合成了人源化的单域抗体,实现了其原核表达,并进行了牛物活性检测;建立了基于人源化的单域抗体的RTA和蓖麻毒素检测方法.结论 研究结果为新型蓖麻毒素小分子拮抗剂的研制奠定了理论和实验基础.     

An animal model of SARS produced by infection of Macaca mulatta with SARS coronavirus

A new SARS animal model was established by inoculating SARS coronavirus (SARS-CoV) into rhesus macaques (Macaca mulatta) through the nasal cavity. Pathological pulmonary changes were successively detected on days 5-60 after virus inoculation. All eight animals showed a transient fever 2-3 days after inoculation. Immunological, molecular biological, and pathological studies support the establishment of this SARS animal model. Firstly, SARS-CoV-specific IgGs were detected in the sera of macaques from 11 to 60 days after inoculation. Secondly, SARS-CoV RNA could be detected in pharyngeal swab samples using nested RT-PCR in all infected animals from 5 days after virus inoculation. Finally, histopathological changes of interstitial pneumonia were found in the lungs during the 60 days after viral inoculation: these changes were less marked at later time points, indicating that an active healing process together with resolution of an acute inflammatory response was taking place in these animals. This animal model should provide insight into the mechanisms of SARS-CoV-related pulmonary disease and greatly facilitate the development of vaccines and therapeutics against SARS.