Functional disomies of the X chromosome influence the cell selection and hence the X inactivation pattern in females with balanced X-autosome translocations: a review of 122 cases.

We reviewed 122 cases of balanced X-autosome translocations in females, with respect to the X inactivation pattern, the position of the X break point and the resulting phenotype. In 77% of the patients the translocated X chromosome was early replicating in all cells analysed. The break points in these cases were distributed all along the X chromosome. Most of these patients were either phenotypically normal or had gonadal dysgenesis, some had single gene disorders, and less than 9% had multiple congenital anomalies and/or mental retardation. In the remaining 23% of the cases the translocated X chromosome was late replicating in a proportion of cells. In these cells only one of the translocation products was reported to replicate late, while the remaining portion of the X chromosome showed the same replication pattern as the homologous part of the active, structurally normal X chromosome. The analysis of DNA methylation in one of these cases confirmed noninactivation of the translocated segment. Consequently, these cells were functionally disomic for a part of the X chromosome. The presence of disomic cells was highly prevalent in translocations with break points at Xp22 and Xq28, even though spreading of X inactivation onto the adjacent autosomal segment was noted in most of these cases. This suggests that selection against cells with a late replicating translocated X is driven predominantly by a functional disomy X, and that the efficiency of this process depends primarily on the position of the X break point, and hence the size of the noninactivated region.(ABSTRACT TRUNCATED AT 250 WORDS)     

γ型干扰素、CD4+CD25+调节性T细胞与自身免疫病

γ型干扰素在适应性免疫应答中起重要作用.在MHC-Ⅱ类分子限制性自身免疫病中,T细胞反应主要以1型辅助性T细胞(Th1)为主,并伴有IFN-γ水平增高,而剔除小鼠胸腺来源的CD4 CD25 调节性T细胞则导致自身免疫病的发生,有研究认为调节性T细胞在诱导免疫耐受产生的过程中起关键性作用.IFN-γ及其受体缺陷小鼠的CD4 CD25 调节性T细胞的免疫抑制能力明显受损,这表明IFN-γ及其受体在CD4 CD25 调节性T细胞免疫调节作用中以及在自身免疫病发生中可能发挥重要而复杂的免疫调节作用.本文仅就IFN-γ与调节性T细胞及自身免疫病发病三者之间关系的研究进展进行简要综述.     

Malignant peripheral neuroectodermal tumors. Histological and immunohistological conditions in 41 cases

In view of the personal observation that malignant peripheral neuroectodermal tumours (MPNT) can present different histological growth patterns, 41 cases of MPNT were histologically and immunohistochemically studied. The median age of the 41 patients was 15 years (range: 9 months - 23 years). There were 27 males and 14 females. Most tumours (23/41) were located in the thoracopulmonary region. In 31/41 cases there was bone as well as soft tissue involvement. The following histopathological patterns were found: Ewing's sarcoma-like (n = 7), atypical Ewing's sarcoma-like (n = 4), neuroblastoma-like (n = 8), rhabdomyosarcoma-like (n = 8), and hemangiopericytoma-like (n = 1). In 2 cases combined patterns were noted, one tumour being characterized by neuroblastoma-like and Burkitt's lymphoma-like features. Most cases of MPNT differed from the cytological features of typical Ewing's sarcoma in that they contained hyperchromatic nuclei with distinct nucleoli. Some reticulin fibrils were found in between the cells of some cases. Immunohistochemically, 19/23 cases reacted positively to vimentin, 29/32 to neuron specific enolase (NSE), 16/28 to protein S-100, and 1/9 to glial fibrillary acidic protein. 12/24 cases reacted positively to NSE and protein S-100. Neurofilaments and desmin were not found in the formalin fixed material of the present study. The results show that most cases of MPNT can be distinguished from typical Ewing's sarcoma by cytological and histological findings. Differential diagnosis from atypical Ewing's sarcoma, neuroblastoma, and rhabdomyosarcoma is possible by immunohistochemistry.     

The effects of pore size and endothelial cell seeding upon the performance of small-diameter e-PTFE vascular grafts under controlled flow conditions

The purpose of this study was to determine the effects of endothelial cell seeding and graft internodal distance upon the performance of 4-mm-ID e-PTFE grafts during acute reduced blood flow conditions. PTFE grafts especially manufactured with three different mean internodal distances (28, 40, and 52 microns) were evaluated. Fifteen dogs (n = 5 for each design of PTFE graft) underwent bilateral carotid artery replacements with 6 cm lengths of 4-mm-ID PTFE grafts. In each dog one graft was seeded with enzymatically derived endothelial cells; the contralateral graft was nonseeded. All grafts were evaluated 5 weeks postoperatively. Dogs with bilaterally patent grafts were subsequently subjected to flow conditions through the graft that were maintained at 30% of the initial flow rates for 4 hr. Following controlled low flows the grafts were excised and assessed for patency, thrombus-free surface area, inner capsule thickness and prostacyclin production. Endothelial cell seeding of these small-diameter e-PTFE vascular grafts improved patency and thrombus-free surface areas in grafts of all pore sizes, with these parameters being greatest in the 40-microns grafts. Inner-capsule healing in these grafts was controlled and related to the pore size. PGI2 production was improved in endothelial cell seeded grafts of all pore sizes. However, neither endothelial cell seeding nor graft pore size affected the performance of these e-PTFE grafts under conditions of reduced blood flows.     

湖南汉族人群MICA基因多态性分析

为了解湖南地区汉族人群MICA基因第2、3和4外显子多态性分布特点,采用PCR-SSP方法对162名无亲缘关系湖南汉族人群MICA等位基因进行分析。结果显示:在湖南汉族人群中共检测出12个等位基因和28种基因型,各等位基因分布频率有差异,其中以MICA*00801基因频率最高(37.9%),其次为MICA*00201/020(20.1%)和MICA*010(17.3%),频率最低的是MICA*019和MICA*031。将MICA基因在湖南汉族人群中的分布与该基因在其他人群中的分布进行比较,显示MICA基因的分布在不同人群之间存在差异,可作为中国人群的遗传标志。     

初中生自我认同对即时通讯与互联网使用关系的调节作用

目的：考察初中生自我认同对即时通讯与网络成瘾之间关系的调节作用。方法：使用即时通讯服务偏好问卷、自我认同问卷和青少年病理性互联网使用量表对北京市某中学初一年级学生进行调查。结果：即时通讯服务偏好能够显著正向预测病理性互联网的使用；自我认同能够显著负向预测病理性互联网的使用：自我认同对即时通讯与网络成瘾之间关系的调节作用显著，对于高自我认同者，即时通讯不能够显著预测病理性互联网的使用，而对于低自我认同者，即时通讯能够显著正向预测病理性互联网的使用。结论：自我认同完成能够减缓即时通讯与病理性互联网使用之间的正向关系，对个体起到保护作用。     

股骨颈松质骨三方向压缩应力松弛蠕变实验

研究正常国人新鲜尸体股骨颈松质骨的压缩粘弹性力学性质,为人工关节的研制提供生物力学理论基础.对10具正常国人新鲜尸体股骨颈松质骨纵向、横向、45°方向试样进行压缩应力松弛、蠕变实验.得出了股骨颈松质骨3个方向的应力松弛、蠕变数据和曲线.对实验数据进行归一化处理,分别用对数、指数一元回归分析的方法处理数据,得出了归一化应力松弛、归一化蠕变函数及曲线.说明股骨颈松质骨纵向组应力松弛量、蠕变量均大于横向组和45°方向组.股骨颈松质骨为各向异性材料.     

小鼠β-防御素2肿瘤疫苗的抗白血病作用研究

目的：探讨小鼠β-防御素2（MBD2）肿瘤疫苗的体内抗白血病作用及其机制。方法：小鼠体内接种转染MBD2的L1210小鼠白血病细胞（L1210-MBD2），观察细胞的致瘤性改变；对长期存活的小鼠用野生型L1210细胞进行二次攻击，探讨瘤苗的免疫保护作用；用照射L1210-MBD2瘤苗注射荷瘤小鼠，检测瘤苗的治疗效果。采用乳酸脱氢酶活性法测定接种瘤苗后小鼠脾脏细胞CTL及NK细胞毒活性，ELISA法检测脾细胞产生IFN-γ及IL-12含量。结果：转染MBD2使L1210细胞致瘤性明显降低（P〈0．05），80％小鼠长期生存；对照组小鼠全部死亡。用野生型L1210细胞二次攻击后100％dx鼠仍能长期生存。照射瘤苗能使50％的荷瘤小鼠长期生存，而对照组小鼠则全部死亡，两者之间具有显著性差异（P〈0．05）。接种MBD2瘤苗后，小鼠脾细胞对L1210的CTL及NK杀伤活性明显增强（P〈0．05），产生IFN-γ、IL-12水平显著升高（P〈0．05）。结论：L1210-MBD2瘤苗通过调节机体细胞免疫反应显示出较强的体内抗白血病作用，为淋巴细胞性白血病的免疫治疗提供了新策略。     

Epiphysial dysplasia: a constant finding in the XXXXY syndrome.

Two patients with the XXXXY syndrome are presented. Both boys are mentally retarded with short stature, muscular hypotonia, and hypogonadism. A constant feature of this syndrome is a varying degree of epiphysial dysplasia probably secondary to hypotonia and growth deceleration.     

抗SARS-CoV抗原的人源Fab段噬菌体抗体库的构建

目的 :利用抗SARS冠状病毒IgG抗体阳性的SARS康复患者外周血淋巴细胞 ,构建人源Fab段抗体文库。方法 :制备外周血淋巴细胞总RNA ,逆转录成cDNA。以其为模板 ,利用针对家族特异性Ig基因的引物扩增重链Fd段和轻链基因 ,并重组到噬菌粒载体pComb3中 ,将重组噬菌粒载体电转化大肠杆菌XL 1Blue,酶切鉴定抗体库的重组率 ,并测定噬菌体抗体库的库容量。结果 :构建了源于SARS康复患者血清中抗Fab段的抗体文库 ,轻链、重链Fd段基因的重组率分别为91%和 75 % ,库容量为 7.2 3× 10 7。结论 :成功地构建了抗SARS CoV抗原的人源Fab段噬菌体抗体库