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101.
椎间盘部分切除对腰椎应力分布影响的有限元分析 总被引:1,自引:0,他引:1
腰椎间盘突出症是骨科常见病之一。椎间盘切除术被广泛应用于本症的治疗。本文采用有限元素分析法观察了椎间盘部分切除前后腰椎应力分布的改变。本研究观察到,在正常情况下,椎体上下缘的中央部位承受较大的应力;椎间盘部分切除术后,椎体上下缘的侧方承采应力大于中央部分。这些结果表明,椎间盘部分切除术后可引起腰椎应力分布紊乱,出现应力集中,引起骨质增生,从而影响手术的远期疗效。 相似文献
102.
目的对110例癫痫患者的24h动态脑电图(AEEG)的应用价值进行了初步探讨。方法使用英国的OxfordMedilog9200型8导磁带记录仪进行24h描记后作离线回放分析,并与普通EEG相比较。结果110例中AEEG异常62例(56.4%),98例中EEG发现异常32例(32.7%)。EEG正常而AEEG异常30例,EEG异常而AEEG正常9例。结论AEEG明显优于EEG,但有时AEEG也不能捕获到间歇期的发作波。分析AEEG记录必需注意将睡眠Ⅰ、Ⅱ期出现的高幅顶尖波、纺锤波与痫样波区分开来,以免导致错误诊断。AEEG对颞叶和额叶底面的致痫灶反应较差,需补做特殊电极的EEG,如蝶骨电极。 相似文献
103.
Inactivation of Exonuclease 1 in mice results in DNA mismatch repair defects,increased cancer susceptibility,and male and female sterility 总被引:12,自引:0,他引:12
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Wei K Clark AB Wong E Kane MF Mazur DJ Parris T Kolas NK Russell R Hou H Kneitz B Yang G Kunkel TA Kolodner RD Cohen PE Edelmann W 《Genes & development》2003,17(5):603-614
Exonuclease 1 (Exo1) is a 5'-3' exonuclease that interacts with MutS and MutL homologs and has been implicated in the excision step of DNA mismatch repair. To investigate the role of Exo1 in mammalian mismatch repair and assess its importance for tumorigenesis and meiosis, we generated an Exo1 mutant mouse line. Analysis of Exo1(-/-) cells for mismatch repair activity in vitro showed that Exo1 is required for the repair of base:base and single-base insertion/deletion mismatches in both 5' and 3' nick-directed repair. The repair defect in Exo1(-/-) cells also caused elevated microsatellite instability at a mononucleotide repeat marker and a significant increase in mutation rate at the Hprt locus. Exo1(-/-) animals displayed reduced survival and increased susceptibility to the development of lymphomas. In addition, Exo1(-/-) male and female mice were sterile because of a meiotic defect. Meiosis in Exo1(-/-) animals proceeded through prophase I; however, the chromosomes exhibited dynamic loss of chiasmata during metaphase I, resulting in meiotic failure and apoptosis. Our results show that mammalian Exo1 functions in mutation avoidance and is essential for male and female meiosis. 相似文献
104.
Shields CM Taylor R Nazarenus T Cheatle J Hou A Tapprich A Haifley A Atkin AL 《Current genetics》2003,44(4):184-194
Saccharomyces cerevisiae ATS1 (-tubulin suppressor 1) was originally identified as a high-copy suppressor of class two -tubulin mutations and was proposed to have a regulatory role in coordinating the microtubule state with the cell cycle. Here, we show that Ats1p interacts with Nap1p, a cytoplasmic protein that regulates the activity of the Cdc28p/Clb2p complex. Loss of Nap1p results in a delayed switch from polar to isotropic bud growth. The delayed switch results in elongated buds. Nap1p and Ats1p interact in two-hybrid and co-immunoprecipitation assays. Both nap1 and ats1 cells have a Clb2p-dependent elongated bud morphology. Deletion of ATS1 partially suppresses the elongated bud morphology and benomyl resistance of nap1 mutants. Our results suggest Ats1p might regulate coordination of the microtubule state with the cell cycle through an interaction with Nap1p.Communicated by S. Hohmann 相似文献
105.
乙/丙型肝炎病毒双重感染患者前C区终止变异低频率 总被引:1,自引:0,他引:1
目的了解乙型肝炎病毒(HBV)与丙型肝炎病毒(HCV)双重感染患者前C区基因变异,及其可能的临床意义。方法用聚合酶链反应(PCR)与限制片段长度多态性(RFLP)来分析25例HBVDNA和HCVRNA均阳性(A组)和31例HBsAg和HBVDNA阳性但抗-HCV和HCVRNA均阴性(B组)的慢性肝病患者前C区密码28终止变异(终28)。结果HBV和HCV双重感染患者(A组)血清HBVDNA第1次PCR阳性率(16%)明显低于单独HBV感染组(65%)(P<0.001);前C终28检出率(28%)亦明显低于单独HBV感染(68%)(P<0.001)。结论提示双重感染患者HBV前C终止变异低频率可能与HBV低水平复制有关 相似文献
106.
Heng-Shuen Chen Fei-Ran Guo Chien-Tsai Liu Yue-Joe Lee Jye-Horng Chen Chia-Chin Lin Sheng-Mou Hou Bor-Shen Hsieh 《International journal of medical informatics》1998,50(1-3):59-68
National Taiwan University College of Medicine (NTUCM) introduced small groups of teaching and basic-clinical integrated courses for medical students in 1992. By using computer network and multimedia techniques, this study tried to overcome barriers to learning in small group teaching. The Department of Medical Informatics of NTUCM established campus networking and computer classrooms and provided Internet and intranet network services including mail, netnews, bulletin board systems (BBS), world wide web (WWW), gopher, ftp and local file servers. To implement an interactive learning environment, the authors first tried mail lists, newsgroups and BBS. Next an integrated learning system prototype on the WWW was developed to provide functions including online syllabus, discussion boards simulated to BBS, online talk, interactive case studies, virtual classroom with video on demand (VOD) and Internet medical resources. The results showed that after the medical students completed the required course of medical informatics and had good network access using a network to communicate with each other became a daily practice. In the future, the system will extend to the tutoring of clinical practice and continuing medical education. The authors expect a national medical education network and more international cooperation and exchange. 相似文献
107.
双胎妊娠44例临床分析 总被引:6,自引:0,他引:6
本文对我院1990~1995年间44例双胎妊娠的分娩方式进行了分析。指出双胎妊娠由于胎位异常、产力异常及妊娠并发症多等因素,难产及手术产率均较单胎明显增高。在25例经阴道分娩的双胎中,阴道手术产率为64%,本组双胎剖宫产率为43.22%。本文认为双胎妊娠的分娩方式应掌握以下原则:当第一胎儿为臀泣、第二胎位为头位,尤其是胎儿较大、羊水较少时,应考虑剖宫产。而单纯的第二胎儿臀位可以经阴道分娩,不必常规剖宫产。 相似文献
108.
CD1d-restricted natural killer T cells are potent targets for human immunodeficiency virus infection 总被引:1,自引:0,他引:1
Invariant human natural killer T cells (NKT) express a restricted T-cell receptor (TCR) Valpha24Vbeta11 repertoire. These cells share both phenotypic and functional similarities between NK and T cells. Given the emerging role of NKT cells as critical cells in bridging the gap between innate and adaptive immunity, we examined their susceptibility to productive human immunodeficiency virus (HIV) infection by T-tropic, M-tropic, and primary isolates of HIV. We generated three human NKT cell clones (CA5, CA29, and CA31). Phenotypic characterization of these Valpha24+ Vbeta11+ clones indicated that they were predominately positive for CD4, CD161, HLA-DR, CD38, CD45RO, and CD95 expression. The NKT cell clones expressed significantly more surface CCR5 molecules/cell and lower CXCR4 molecules/cell than phytohaemagglutinin-stimulated peripheral blood mononuclear cells (PBMC). Consistent with the surface expression of CCR5 and CXCR4, the NKT clones were also selectively susceptible to HIV M-tropic, T-tropic, and primary isolate infection, as evaluated by both HIV p24 enzyme-linked immunosorbent assay and intracellular staining of HIV proteins. The amount of p24 production was dependent on the NKT clone studied and the HIV strain used. Clones CA29 and CA31 were also susceptible to HIV IIIB infection. The virions produced by these clones were able to productively infect PHA-stimulated PBMCs with the same kinetics as for primary infection of CD4+ blast. Collectively, this data demonstrates that NKT cells can be a target for productive HIV infection but with a lag in the time to peak p24 production. 相似文献
109.
目的 评定旅游者的心理健康状况。方法 对我市某旅行社外出旅游者进行症状自评量表 ( SCL-90 )测试 ,并将结果与中国正常人常模进行比较。结果 旅游者在人际关系和焦虑两项因子分高于常模 ,其中人际关系敏感因子分差异显著( P<0 .0 5 ) ,精神病性因子分低于常模 ,并具有显著差异 ( P<0 .0 5 ) ;单独外出旅游者与结伴外出旅游者相比在人际关系敏感和焦虑两个因子方面具有显著性的差异 ( P<0 .0 5 )。结论 旅行社对旅游者的心理健康状况应引起重视 ,并对存在的心理问题进行必要的干预 相似文献
110.
hTRT催化功能区基因克隆及其在肿瘤中的表达 总被引:19,自引:2,他引:19
目的 研究端粒酶蛋白hTRT基因在肿瘤中的表达及其意义。方法 用RT-PCR法检查Hela细胞与PG细胞的hTRT表达水平,将Hela细胞的hTRT催化功能克隆,并进行测序比较,应用原位杂交技术对肿瘤组织中的hTRT和hTR(端粒酶RNA组分)基因进行检测。结果 Hela细胞与PG细胞均有hTRT表达,Hela细胞hTRT催化功能区cDNA序列与文献报道一致,原位杂交结果显示hTRT与hTR的协同 相似文献