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991.
Purpose This study was conducted to evaluate the diagnostic usefulness of gray level parameters in order to distinguish healthy bone from osteoblastic metastases on digitized radiographs. Materials and methods Skeletal radiographs of healthy bone (n = 144) and osteoblastic metastases (n = 35) were digitized using pixels 0.175 mm in size and 4,096 gray levels. We obtained an optimized healthy bone classification to compare with pathological bone: cortical, trabecular, and flat bone. The osteoblastic metastases (OM) were classified in nonflat and flat bone. These radiological images were analyzed by using a computerized method. The parameters (gray scale) calculated were: mean, standard deviation, and coefficient of variation (MGL, SDGL, and CVGL, respectively) based on gray level histogram analysis. Diagnostic utility was quantified by measurement of parameters on healthy and pathological bone, yielding quantification of area under the receiver operating characteristic (ROC) curve, AUC. Results All three image parameters showed high and significant values of AUC when comparing healthy trabecular bone and nonflat bone OM, showing MGL the best discriminatory ability (0.97). As for flat bones, MGL showed no ability to distinguish between healthy and flat bone OM (0.50). This could be achieved by using SDGL or CVGL, with both showing a similar diagnostic ability (0.85 and 0.83, respectively). Conclusion Our results show that the use of gray level parameters quantify healthy bone and osteoblastic metastases zones on digitized radiographs. This may be helpful as a complementary method for differential diagnosis. Moreover, our method will allow us to study the evolution of osteoblastic metastases under medical treatment.  相似文献   
992.
目的 为了研究中国庚型肝炎病毒(HGV)非结构(NS3)区基因结构特征。方法 利用逆转录-半巢式-聚合酶链反应从河南1份HGV RNA阳性血清获得覆盖HBV NS3全长cDNA的4个片段,并克隆到pcDNAⅡ载体中,采用Sanger双脱氧末端终止法测定全部cDNA序列。结果 发现克隆到的包括HBV NS3区在内的cDNA序列和度为2137个核苷酸,编码711个氨基酸。与国内外已测定的5株全序列的相  相似文献   
993.
The identification of the new allele HLA-A*6813, which was found in a woman of Syrian origin and her son, is described. In the sequence analysis the new allele differs from A*68011 by positions 259 (A>G) and 261 (C>G) in exon 2. As the structure is thus identical to the HLA-A consensus sequence it is likely that the new allele originated by gene conversion. At the protein level, the new allele has one amino acid difference from A*6801 (Asn63Glu), which results in a distinct banding pattern in one dimensional-isoelectric focusing. Amino acid residue 63 contributes to the formation of pocket A and B and is thus important for peptide binding. A*6813 was serologically detectable only by two of six polyclonal, but by three monoclonal antisera. The restricted serological A68 activity may be explained by altered peptide binding as presented peptides can affect the serological recognition of major histocompatibility complex (MHC) class I molecules. Moreover, our findings suggest that a possible mismatch with the other known A*68 variants may impair clinical outcome of bone marrow transplantation.  相似文献   
994.
Equine arteritis virus (EAV) is a member of the Arteriviridae family, that includes lactate dehydrogenase-elevating virus (LDV), porcine reproductive and respiratory syndrome virus (PRRSV), and simian haemorrhagic fever virus (SHFV). Equine arteritis is a contagious disease of horses and is spread via respiratory or reproductive tract. The objective of the present study is to evaluate the possibility for developing a model system for prevention horses against an EAV infection by DNA vaccination. A cDNA bank from the RNA of EAV was established. This gene library contains the translation unit of the EAV open reading frames (ORF) 1 to 7. The identity of the cDNA was confirmed by nucleotide sequence analysis. Using this defined EAV cDNA gene library the cDNA sequence of the viral ORFs were molecularly cloned into the corresponding sites of well characterized and powerful expression vectors (pCR3.1, pDisplay, and/or pcDNA3.1/HisC).The capability of these recombinant plasmids expressing the gene products of the individual viral ORFs 3 to 5, and 7 in induction of an immune response in mouse system was investigated. The Balb/c mice (ten mice per assay) were inoculated with the DNA of the constructed expression vectors harboring and expressing the EAV cDNA of the viral ORFs. The Balb/c mice were injected with about 100 g DNA diluted in 100 l PBS. The DNA was injected subcutaneously and into the tibialis cranialis muscle (Musculus gastrocnemius). The mice were boosted 3 to 5 times with the same quantities of DNA and under the same conditions at about two week intervals. Control mice received the same amount of parental expression vectors via an identical route and frequency.The pre- and post-vaccinated sera of the individual animals were screened by neutralization tests (NT). Neutralizing antibodies against EAV were detected when the animals were inoculated with the DNA of the expression vectors harboring cDNA of the EAV ORFs 5 and 7. Highest NT-titers were observed when the animals were administered with the cDNA of ORF 5 and/or with the cDNA of the neutralization determinants of EAV that is located on the N-terminal ectodomain of the gene product of ORF 5 between the amino acid positions 1–121. These results obtained from these studies justified proofing the capability of the EAV cDNA sequences of the viral genes including ORFs 5 and 7 in the autologous animal system horse.  相似文献   
995.
In some patients with chronic liver disease induced by hepatitis B virus, viral DNA is known to persist in low concentration in serum after seroconversion to hepatitis B surface antibody-positivity. This phenomenon has, however, not been documented in asymptomatic black African carriers of hepatitis B virus. Using nested amplification by the polymerase chain reaction, we detected low concentrations of hepatitis B virus DNA in the serum of 6 of 23 (26%) healthy black African adults with normal liver function and with hepatitis B virus surface antibody as the only serological marker of the virus. This finding offers one explanation for the earlier observation of integrated hepatitis B virus DNA in hepatocellular carcinomas in black Africans whose serum was positive for surface antibody alone. A number of genetic changes were found in the six isolates that might be responsible for evasion of the immune response and persistence of the virus. Isolated mutations were detected in the "a" determinant of the surface gene and in the encapsidation signal. In all five isolates sequenced in the core promoter, mutations were present in the upstream regulatory region. Recombination between genotypes A and D was present in three of the isolates, including both of those in which the entire genome was sequenced. This change in genotype also overlapped the amino end of the polymerase domain and may result in sufficiently low levels of replication to allow viral persistence. Topoisomerase 1 specific trinucleotides were concentrated in the vicinity of the recombination breakpoints.  相似文献   
996.
目的对重庆市2004—2007年报告的突发公共卫生事件进行分析,以加强对突发公共卫生事件的预防和应急处理。方法应用描述流行病学方法,分析事件特征。结果全市4年报告突发公共卫生事件478起,发病19884例,死亡56例;渝东南地区多发,时间分布基本呈双高峰:传染病事件占80.98%.学校事件占78.87%;事件平均报告时间3.44d,平均处理时间46.72d。结论突发公共卫生事件的发生与地区经济文化水平密切相关;应提高对乙、丙类传染病和非法定传染病事件的重视程度;学校卫生工作有待进一步加强:突发公共卫生事件报告管理体系有待进一步理顺。  相似文献   
997.
目的 探讨广州地区儿童感染的星状病毒基因组分子结构特点和基因型.方法 参考GenBank上的星状病毒基因组设计分段扩增引物,进行RT-PCR分段扩增星状病毒基因组,克隆于T载体上,序列测定,用Clustal W和DNAStar软件分析基因组序列.结果 星状病毒HASTVgz01全基因组为6721 bp,提交到GenBank上的序列号为DQ344027,其中5'端非编码区(5'UTR)长82bp,3'端非编码区末端长81 bp,病毒基因组编码区全长6558个核苷酸,分别编码ORF1a、ORF1b、ORF2,ORF1a基因长2763 bp(83~2845 nt),ORF1b基因长1557bp(2785~4332 nt),其中ORF1a、ORF1b两基因有71个核苷酸的重叠区;ORF2全长2316 nt,位于基因组中4325~6640 nt.ASTVgz01与GenBank中8种基因型星状病毒的ORF2基因氨基酸序列同源性比较发现,HASTVgz01与4型的同源性为93%,其他的同源性在61%~70%之间.结论 广州地区儿童腹泻感染的星状病毒HASTVgz01全基因组为6721bp,GenBank序列号为DQ344027,HASTVgz01与4型星状病毒的ORF2基因氨基酸序列比较同源性为最高,确认HASTVgz01是4型星状病毒.  相似文献   
998.
CT perfusion imaging constitutes an important contribution to the early diagnosis of acute stroke. Cerebral blood flow (CBF), cerebral blood volume (CBV) and time-to-peak (TTP) maps are used to estimate the severity of cerebral damage after acute ischemia. We introduce functional cluster analysis as a new tool to evaluate CT perfusion in order to identify normal brain, ischemic tissue and large vessels. CBF, CBV and TTP maps represent the basis for cluster analysis applying a partitioning (k-means) and density-based (density-based spatial clustering of applications with noise, DBSCAN) paradigm. In patients with transient ischemic attack and stroke, cluster analysis identified brain areas with distinct hemodynamic properties (gray and white matter) and segmented territorial ischemia. CBF, CBV and TTP values of each detected cluster were displayed. Our preliminary results indicate that functional cluster analysis of CT perfusion maps may become a helpful tool for the interpretation of perfusion maps and provide a rapid means for the segmentation of ischemic tissue.  相似文献   
999.
目的克隆我国分离的汉坦病毒A9株L片段全长cDNA,并测定其核苷酸序列.方法用逆转录-聚合酶链反应(RT-PCR)技术分段扩增汉坦病毒A9株全部L片段,用T-A克隆方法进行PCR产物克隆,测定PCR产物的核苷酸序列.通过亚克隆将分段的L片段连接成全长cDNA克隆.结果A9株的基因组L片段长度为6533个核苷酸,腺嘌呤核苷酸和尿嘧啶核苷酸丰富(%A+U=62.47).包含有一个单一的开放读码框架(ORF),编码一个标准的质量为2.46×105的蛋白,含有2151个氨基酸.A9株与76-118、C1-1和C1-2株的同源性最高,达到83.8%.与TULA病毒的关系较远,其核酸序列的同源性为65.8%.将推导的A9株编码的氨基酸序列与其他21种负链RNA病毒的依赖RNA的RNA聚合酶的氨基酸序列以及汉坦病毒几个代表株的L片段氨基酸序列进行比较,显示A9编码的RNA聚合酶也有6个比较保守的区域以及几个极端保守的氨基酸残基.结论汉坦病毒A9株L片段具有和其他汉坦病毒RNA聚合酶相似的核苷酸一级结构,通过对推导的氨基酸分析,该片段具有一些在RNA病毒聚合酶中都存在的保守区域.  相似文献   
1000.
布氏显微镜活血分析: 细胞流变学研究的新方法   总被引:14,自引:0,他引:14  
布氏显微镜活血分析:细胞流变学研究的新方法骆秉铨*黄荣国*陈兴新*细胞流变学是研究血细胞流动变形的科学,在方法学上发展了一些比较成熟的方法,但多不能直接动态观察细胞水平的真实改变,有待完善和创新。我们采用布氏多功能显微镜的活血分析法[1],在高放大倍...  相似文献   
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