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51.
慢性乙型肝炎表面抗原携带者前S1基因的高度异质性 总被引:1,自引:0,他引:1
应用半巢式聚合酶链式反应(PCR)从一例慢性HBsAg携带者血清中扩增出HBV前S1基因,将其克隆于噬菌体M13mp19中进行序列分析。结果发现:与同源性最好的HBVadr野生林相比,所测的10个克隆均有替代和插入突变,9个克隆有缺失突变,10个克隆的核苷酸变异率为5.0%-17.0%,氨基酸的变异率为13.0-60.0%;10个克隆之间的核苷酸变异率为2.3%-24.3%,氨基酸的变异率为14. 相似文献
52.
采用毛细管流交仪测定了PBT/PC共混物的表观粘度、剪切应力,观察了不同共混物组成和不同温度下共混物的流变行为,并借助扫描电镜对共混物和微观形态结构进行分析。结果表明:PBT/PC熔体共混物的流变行为接近假塑性流体.温度对共混物的流变行为影响很大,共混物的熔体粘度在PBT/PC为90/10和60/40时呈双极值.共混物为两相结构,PC含量为4-50%时呈两互锁结构。 相似文献
53.
Teresa S. Priebe Edward N. Atkinson Bih-Fang Pan J. Arly Nelson 《Cancer chemotherapy and pharmacology》1992,29(6):485-489
Summary PANC02 is a ductal adenocarcinoma of the pancreas that is resistant to every known class of clinically active antitumor agent. To study the mechanism(s) underlying the intrinsic drug resistance of this tumor, a mammary adenocarcinoma (CA-755) that also grows in C57/BL mice and is known to be drugsensitive was used for comparison. PANC02 resistance and CA-755 sensitivity to several antitumor agents and to X-ray therapy was confirmed in mice, and PANC02 also demonstrated relative resistance in tissue culture. Relative to Chinese hamster ovary (CHO) and CA-755 cells, PANC02 did not appear to show a higher rate of mutation to drug resistance in culture as based on the 6-thioguanine resistance marker. Although P-glycoprotein characteristic of the multidrug resistance (MDR) phenomenon could be demonstrated at the mRNA level using a sensitive RNAse protection assay, the level of expression found was several orders of magnitude lower than that observed in phenotypic MDR cell lines. Furthermore, quinidine failed to increase the sensitivity of PANC02 cells to Adriamycin under conditions that clearly potentiated the toxicity of the drug to a CHO cell line exhibiting classic MDR traits. The heterogeneity in the distribution of drugs was inferred as being significantly greater in PANC02 versus CA-755 cells in vivo as based on measurements of within-animal, within-tumor variance in the distribution of the marker compounds inulin and antipyrine. Although it may not be the only mechanism involved, this greater intratumor heterogeneity in drug distribution could theoretically play a major role in the intrinsic drug resistance of PANC02 in vivo.Supported by grant CH-458 from the American Cancer Society, by grant CA-28034 from the National Cancer Institute, and in part by Cancer Center Core Support grant, NIH-NCI-CA-16672. Animals were maintained in facilities approved by the American Association for Accreditation of Laboratory Animal Care and in accordance with current United States Department of Agriculture, Department of Health and Human Services, and National Institutes of Health regulations and standards 相似文献
54.
Sera from 130 first trimester pregnant women were tested for their serum antibody level against a naturally occurring serum antigen purified from non-pregnancy sera. IgG and IgM antibody level was measured using enzyme linked immunosorbant assay. Results indicate that patients with multiple abortion (n=26) have significantly (p=0.0029) lower level of IgG antibody and significantly (p=0.0001) higher level of IgM antibodies; against the serum antigen as compared to the patients with successful pregnancies with no history of miscarriage (n=63). Western blot analysis identified the scrum antigen recognized by the IgM antibody as a 24 kDa molecular mass component. These IgG and IgM antibodies may play an important role in the outcome of pregnancy. 相似文献
55.
56.
探讨荧光原位杂交法(FISH)对母血中胎儿有核红细胞(NRBC)进行无创性产前诊断的可行性。20例孕龄15-20周的孕妇外周血经不连续密度梯度离心、制片、显微镜下识别并共计数NRBC及定位,然后行Y染色体的FISH检测。结果发现10例孕男性胎儿的孕妇外周血细胞涂片中每例均有阳性杂交信号出现;阳性率为60%(24/40)。10例孕女性胎儿的孕妇外周血细胞涂片中1例出现阳性杂交信号;阴性率为95%(38/40),假阳性率仅为5%(2/40)。结果提示FISH法对于用母血中分离到的胎儿细胞进行染色体异常的无创性产前遗传学检查具有重要意义。 相似文献
57.
INAUGURAL ARTICLE by a Recently Elected Academy Member:The cell surface metalloprotease/disintegrin Kuzbanian
is required for axonal extension in Drosophila 下载免费PDF全文
Douglas Fambrough Duojia Pan GeraldM. Rubin CoreyS. Goodman 《Proceedings of the National Academy of Sciences of the United States of America》1996,93(23):13233-13238
It has long been suspected that proteolytic activity associated with advancing growth cones may be required for axon extension. We have isolated mutations in the kuzbanian (kuz) gene, which is expressed in the nervous system and encodes a putative zinc metalloprotease with a disintegrin domain. Drosophila embryos with loss-of-function mutations in kuz have dramatic defects in the development of central nervous system axon pathways, with many axons stalling and failing to extend through the nerve cord. This phenotype is rescued by panneural expression of kuz mRNA in the embryo. These results show that the Kuz metalloprotease is required for axon extension, suggesting a requirement for proteolytic activity at the growth cone surface. 相似文献
58.
59.
假体隆乳术后并发症的防治 总被引:9,自引:0,他引:9
目的探讨乳房假体隆乳术后并发症产生的相关因素及预防方法。方法对198例患者乳房假体隆乳术后1~17年出现的并发症进行分析,阐述防治措施,针对不同情况进行相应的处理。结果本组198例患者,其中92例患者随访半年至1年,除Ⅲ°包膜挛缩患者术后仍出现Ⅱ~Ⅲ°包膜挛缩外(包膜松解术后3例,包膜切除术后4例),余患者对治疗效果满意。结论乳房假体隆乳术后出现的并发症,多数是可以预防和治疗的,只要术中操作规范,对并发症及早准确的处理,是提高手术效果,减少并发症发生的有效方法。 相似文献
60.