Induction of erythroid differentiation in K562 cells and natural killer cell-mediated lysis: distinct effects at the level of recognition and lysis in relation to target cell proliferation

The erythroleukemic K562 cell line was induced to erythroid differentiation by a variety of agents, including hemin, bleomycin, and cytosine arabinoside. The sensitivity of induced cells to binding and lysis by non-sensitized peripheral blood mononuclear cells (MNC) in agarose was studied in relation to the target cell division rate. Differentiated K562 cells formed a lower proportion of conjugates with MNC, when compared with non-induced controls. The reduction correlated significantly with the level of differentiation, irrespective of the inducer and the proliferative status. The differentiation-induced alterations of lysis, however, were strongly influenced by the modification of target cell growth rate which was caused by the differentiating agent. These data suggest that target cell differentiation has distinct effects upon the steps of recognition and lysis by natural killer cells.     

一次性注射器填充级HDPE专用料的研制

通过对母料载体树脂的筛选,无机填料的选择,添加性能优良的耐辐射助剂,制成了具有耐辐射性能、加工性能良好的母料,该母料的制备工艺简单。本文所述的填充级HDPE专用料是将HDPE与填充母料经过简单掺混制成的。经测试专用料满足国家医药标准YY 0114—93《医用输液、输血、注射器聚乙烯专用料》的要求。制品厂试验表明:该填充级的HDPE专用料加工性能良好,用该填充级HDPE专用料注射成型的注射器芯杆装配成一次性注射器满足国家专业标准ZBC 31009—87《一次性无菌注射器》的要求。该填充母料的加入可大大降低材料的成本,100份HDPE 7006A可添加67份填充母料,该填充级专用料的价格比HDPE树脂降低约1500元/吨,因此该填充级HDPE专用料的推广和使用具有良好的经济效益。     

Novel single nucleotide polymorphisms of the human nuclear factor kappa-B 2 gene identified by sequencing the entire gene

The nuclear factor kappa-B 2 (NFKB2) gene is a member of the NFKB/Rel gene family, which is known to be a pivotal regulator of the acute phase of the inflammatory response and of immune responses. We identified three novel single nucleotide polymorphisms (SNPs) and determined their allelic frequencies, as determined by the sequencing of 48 alleles of the entire gene in a Japanese population sample. Two of the three polymorphisms were identified at nucleotide (nt) position 1837 (T/C) and nt position, 1867 (GG/G) in the upstream region of the gene. The other polymorphism was identified at nt position 2584 (G/T) within intron 1. These polymorphisms will be useful in genetic studies of the processes involved in inflammatory responses and in bone differentiation. Received: October 17, 2000 / Accepted: October 23, 2000     

Distribution of TT virus genomic groups 1-5 in Brazilian blood donors, HBV carriers, and HIV-1-infected patients

Human isolates of the highly prevalent TT virus (TTV) have been classified into five major genomic groups (1-5). The geographical distribution of the groups throughout the world is not well known. Five different PCR assays were developed in an attempt to amplify specifically TTV DNAs of each genomic group. Serum samples collected from 72 Brazilian adults (24 voluntary blood donors, 24 hepatitis B virus (HBV) carriers, and 24 human immunodeficiency virus type 1 (HIV-1)-infected patients) were tested. TTV DNA from at least one genomic group was detected in 11 (46%) blood donors, 13 (54%) HBV carriers, and 24 (100%) HIV-1 patients. All five genomic groups were detected in the three populations, with the exception of group 2 in blood donors. Some samples, negative with all five specific assays, were positive with the commonly used untranslated region (UTR) PCR system. On the other hand, TTV DNA was detected in some samples by using specific assays but not with the UTR PCR. Mixed infections with 2-5 TTV isolates from different groups were detected in 21% blood donors, 29% HBV carriers, and 71% HIV-1 patients. Fifteen PCR products (three obtained with each assay) were sequenced. Most sequences showed high (>86%) homology with those of TTV isolates belonging to their presumed groups. However, three sequences had low homology with all TTV sequences available from the DNA databanks. In conclusion, TTV isolates belonging to all five known genomic groups circulate in Brazil, and the results suggest the existence of new and as yet uncharacterised major genomic groups.     

Impact of elective single embryo transfer on the twin pregnancy rate

BACKGROUND: It is unclear how the implementation of elective single embryo transfer in clinical practice would affect clinical pregnancy and delivery rates and multiple birth rates. METHODS: This retrospective study analysed 1871 IVF/ICSI cycles carried out from 1997 to 2001 in the IVF programme of a single university infertility clinic. RESULTS: The number of elective single embryo transfers increased from 11 to 56%. At the same time the clinical pregnancy rate was relatively stable; mean 34.0% (range 28-42). The number of embryos per embryo transfer decreased from 1.8 to 1.3. The multiple pregnancy and delivery rates dropped markedly from 25 to 7.5% and from 25 to 5% respectively. CONCLUSIONS: An elective single embryo transfer programme can be adopted in daily practice that decreases the twinning rate to <10% and does not affect the overall pregnancy rate.     

Elective single day 3 embryo transfer halves the twinning rate without decrease in the ongoing pregnancy rate of an IVF/ICSI programme

BACKGROUND: Data on the effect of elective single embryo transfer (eSET) on the total and multiple pregnancy rates of an IVF/ICSI programme are reported. METHODS AND RESULTS: A retrospective cohort analysis of eSET was carried out over a 4 year period. A total of 1559 cycles resulted in 1464 transfers; 299 transfers of one top quality embryo (20.4%) and 86 of one non-top quality embryo (5.9%) yielded 149 conceptions (49.8%) with 105 ongoing pregnancies (35.1%) and 26 conceptions (30.2%) with 19 ongoing implantations (22.1%) respectively; 1079 transfers of two (n = 853; 58.3%) or more than two (n = 226; 15.4%) embryos yielded 366 ongoing pregnancies (33.9%). The ongoing pregnancy rates for the years between 1998 and 2001 were 35.9, 27.9, 31.9 and 31.0% per oocyte retrieval and 38.5, 29.4, 34.1 and 33.2% per transfer. There were no differences in pregnancy rates between any of the years. The average ongoing pregnancy rate (>12 weeks) over the 4 years was 31.5% per started cycle and 33.5% per transfer; the average number of embryos transferred decreased from 2.26 (1998) to 1.79 (2001); the multiple pregnancy and twinning rates dropped from 33.6 and 29.5% (1998) to 18.6 and 16.3% (2001) respectively. CONCLUSIONS: Judicious application of eSET can halve the twinning rate while maintaining the overall pregnancy rate.     

抗人大肠癌单链抗体的构建、表达及其体内外生物学活性的检测

目的 将抗人大肠癌单克隆抗体ND-1(mAb)的VR和VL基因进行重组，构建和表达ND－1scFv，并对其在体内外的生物学活性进行检测。采用RT－PCR技术，从能够分泌mAb ND-1的鼠杂交瘤细胞中扩增VH和RL基因，通过重叠延伸拼接PCR在VH和VL基因间引入连接短肽，体外构构建ND－1scFv基因，并在大肠杆菌中表达。采用间接免疫荧光（IFA）EY IF工IMPG-1scFv的免疫学活性。用^99Tc^m标记ND－1scFv后，将偶联物给予荷瘤裸鼠，观察其在动物体内的显像及生物学分布。结果 SDS－PAGEW显示，重组蛋白Mr为30000，同预期结果一致。IFA及ELISA检测表明，ND－1scFv保留了与亲本抗体相近的免疫学活性，对表达相应抗原的靶细胞具有行异结合活性。体内放射免疫实验显示，^99Tc^m-ND-1scFv在荷瘤小鼠体内的生物学分布，呈明显的肿瘤积聚趋向，注入体内1h血中T／NT即在2．61。结论 获得免疫学活性良好的ND－1scFv，对荷瘤动物体内肿瘤的定位快速，准确，可望成为有效的肿瘤诊断和治疗的导向载体。     

杂合型单核苷酸多态性定量焦测序测定法用于唐氏综合征快速诊断的探索

目的 通过筛查人21号染色体上的杂合型单核苷酸多态性(single nucleotide polymorphism,SNP)位点,初步建立基于定量焦磷酸测序反应的唐氏综合征分子诊断方法.方法 基于改进引物设计的等位基因特异性扩增法,在21号染色体上选取7个SNP位点进行杂合子筛选,通过焦测序法检测SNP中两个等位基因型的比值,并作为诊断唐氏综合征的依据.结果 通过对84名正常中国人基因组样本进行筛查,得到6个杂合率较高的SNP位点.6个SNP位点的杂合子覆盖率为92.9%.应用这6个SNP位点对10例唐氏综合征患者的样本进行了焦测序定量检测,结果表明10例患者样本中有9例样本的两个基因型比值为2:1或1:2,1例未检出杂合子,检出率为90%.结论 初步建立了一种唐氏综合征辅助诊断方法,具有成本低、操作简单、快速和结果明了的优点,可以有效地快速诊断唐氏综合征,为今后进一步完善该方法,并将其用于临床诊断奠定了基础.     

PPARY2基因Pro12Ala和C1431T多态性及其单倍型与2型糖尿病和肥胖的相关性研究

目的 研究过氧化物体增殖活化受体γ2(peroxisome proliferator activated receptorγ2,PPARγ2)基因Pro12Ala和C1431T多态性及其单倍型与汉族人2型糖尿病、肥胖的关系.方法 应用聚合酶链反应-限制性片段长度多态性的方法,对207例2型糖尿病患者和101名非糖尿病对照者进行PPARγ2基因Pro12Ala和C1431T多态性研究.结果 (1)在非糖尿病对照人群中Aal 12等位基因频率是0.064,T1431等位基因频率是0.252.单倍型分析显示Pro12Ala和C1431T两个位点连锁不平衡(D'=0.63,r2=0.074),组成了3种常见单倍型Pro-C、Pro-T和Ala-T.(2)Pro12Ala和C1431T多态性分布及其单倍型分布频率在2型糖尿病组与对照组组间差异均无统计学意义(P>0.05).(3)Pro12Ala变异与糖尿病患者的血压、血脂相关,地等位基因降低非肥胖糖尿病患者的舒张压(P<0.05),而对肥胖糖尿病患者的血脂水平无保护作用(P<0.05);C1431T多态性与糖尿病患者的超重和肥胖相关,超重和肥胖的糖尿病者T等位基因频率相对较高(P<0.05).结论 Pro12Ala和C1431T多态性可能在汉族人糖尿病发病中不是起主要作用;C1431T多态性与糖尿病患者的超重和肥胖相关.     

DNA fingerprinting of sister blastomeres from human IVF embryos

BACKGROUND: Previously published single cell DNA fingerprinting systems have been plagued by high rates of allele drop-out (ADO) and preferential amplification (PA) preventing clinical application in preimplantation genetic diagnosis. METHODS: Tetranucleotide microsatellite markers with high heterozygosity, known allelic size ranges and minimal PCR stutter artefacts were selected for chromosomes X, 13, 18 and 21 and optimized in a multiplex fluorescent (FL)-PCR format. FL-PCR products were analysed using the ABI Prism 377 DNA sequenator and Genescan software. Validation of the DNA fingerprinting system was performed on single diploid (n = 50) and aneuploid (n = 25) buccal cells and embryonic blastomeres (n = 21). RESULTS: The optimized pentaplex PCR DNA fingerprinting system displayed a high proportion of successful amplifications (>91%) and low ADO and PA (<6%) when assessed on 50 human buccal cells. DNA fingerprints of single cells from a subject with Down's syndrome detected the expected tri-allelic pattern for the chromosome 21 marker, confirming trisomy 21. In a blind study on 21 single blastomeres, all embryos were identifiable by their unique DNA fingerprints and shared parental alleles. CONCLUSIONS: A highly specific multiplex FL-PCR based on the amplification of five highly polymorphic microsatellite markers was developed for single cells. This finding paves the way for the development of a more complex PCR DNA fingerprinting system to assess aneuploidy and single gene mutations in IVF embryos from couples at genetic risk.