Prenatal diagnosis of Down syndrome using cell-free fetal DNA in amniotic fluid by quantitative fluorescent polymersase chain reaction

Backgroud Amniotic fluid （AF） supernatant contains cell-free fetal DNA （cffDNA） fragments.This study attempted to take advantage of cffDNA as a new material for prenatal diagnosis,which could be combined with simple quantitative fluorescent polymerase chain reaction （QF-PCR） to provide an ancillary method for the prenatal diagnosis of trisomy 21 syndrome.Methods AF supernatant samples were obtained from 27 women carrying euploid fetuses and 28 women carrying aneuploid fetuses with known cytogenetic karyotypes.Peripheral blood samples of the parents were collected at the same time.Short tandem repeat （STR） fragments on chromosome 21 were amplified by QF-PCR.Fetal condition and the parental source of the extra chromosome could be determined by the STR peaks.Results The sensitivity of the assay for the aneuploid was 93％ （26/28; confidence interval,CI：77％-98％） and the specificity was 100％ （26/26; CI：88％-100％）.The determination rate of the origin of the extra chromosome was 69％.The sensitivity and the specificity of the assay in the euploid were 100％ （27/27）.Conclusions Trisomy 21 can be prenatally diagnosed by the QF-PCR method in AF supernatant.This karyotype analysis method greatly reduces the requirement for the specimen size.It will be a benefit for early amniocentesis and could avoid pregnancy complications.The method may become an ancillary method for prenatal diagnosis of trisomy 21.     

反向导引过线器在关节镜手术中的应用

目的 探讨反向导引过线器在关节镜下对半月板、前交叉韧带、肩袖进行缝合过线操作中的应用效果。方法 回顾性队列研究。纳入2015年8月—2020年12月赤峰市第二医院106例关节镜下缝合重建患者的临床资料。其中男55例、女51例,年龄24~82岁。按照缝合工具分组：使用普通缝合钩41例,为对照组;使用反向导引过线器65例,为观察组。观察指标：根据2种缝合工具的操作复杂程度、缝合过线难易程度、缝合过线操作时间、副损伤、缝合质量、完成情况自制评分标准,进行综合评分,评价和比较2组缝合效果的优良率。结果 患者术后手术切口均一期愈合。2组患者的年龄、性别、受伤缝合部位等基线资料比较,差异均无统计学意义（P值均>0.05）。对照组缝合效果：优14例、良15例、差12例,优良率70.73%（29/41）;观察组缝合效果：优47例、良18例、差0例,优良率100.00%（65/65）,2组比较差异有统计学意义（χ²=18.64,P<0.001）。结论 反向导引过线器在关节镜下对半月板、交叉韧带及肩袖过线缝合操作时,具有操作便捷、缝合质量可靠、缝合强度大、操作时间短、副损伤小等优点,在临床中具有较好的推广价值。     

Ser9 phosphorylation causes cytoplasmic detention of I2/SET in Alzheimer disease

The nuclear protein I₂^PP2A/SET, an endogenous inhibitor of protein phosphatase-2A (PP2A), is increased and translocated to the cytoplasm in the neurons of Alzheimer's disease (AD) brains, and PP2A activity in cytoplasm is compromised. However, it is not fully understood how SET is retained in the cytoplasm. By generating a phosphorylation site-specific antibody, we found in the present study that SET is phosphorylated at Ser9, by which it is accumulated in the cytoplasm of the AD brains. Further studies demonstrate that both the phosphor-mimic and casein kinase (CK)II-mediated phosphorylation at Ser9 interferes with the formation of the SET/importin-α/importin-β complex, and thus inhibits SET nuclear import and induces the cytoplasmic detention of SET. Interestingly, Ser9 is nested in the center of the sequence ⁶AKVSKK¹¹ of SET, which is consistent with a classical nuclear localization signal (NLS). To test whether ⁶AKVSKK¹¹ is a new NLS of SET, we mutated SET lysine 7, lysine 10, and lysine 11 to alanine acid (K7A, K10A, K11A) respectively, and expressed these mutants in HEK293/tau cells. We found that expression of SET (K11A) led to a nuclear import defect of SET, and application of a synthesized peptide Tat-AAKVSKKE that can competitively bind to importin α/β resulted in cytoplasmic detention of SET. Finally, phosphorylation of SET aggravates PP2A inhibition and leads to tau hyperphosphorylation. In conclusion, the current study has identified a novel mechanism that causes cytoplasmic detention of SET with a new NLS-dependent CKII-associated phosphorylation of Ser9, suggesting that inhibition of CKII arrests cytoplasmic accumulation of SET and thus preserves PP2A activity in AD brains.     

塔里木盆地哈拉哈塘地区碳酸盐岩裂缝预测

采用基于成因分析的间接方法或地震资料直接预测方法预测不同尺度的裂缝,裂缝预测缺乏层次性及针对性,预测结果多解性强、精度低。针对不同尺度裂缝,以裂缝地质成因为指导,有针对性选取不同地质、地震信息逐级识别大(千米级别)、中(百米级别)、小(十米级别)不同尺度裂缝。大尺度裂缝派生中尺度裂缝,中尺度裂缝控制小尺度裂缝发育,逐级约束、分层次预测裂缝能够提高裂缝预测精度。大尺度裂缝受主断裂控制,通过构造地质建模刻画断裂期次、级别及类型,结合断控裂缝的地质成因规律定性地预测大尺度裂缝分布范围。大尺度裂缝派生中尺度发育,在大尺度裂缝预测成果约束下,选取叠后地震资料及精细相干技术识别中尺度裂缝。小尺度裂缝受大尺度、中尺度裂缝控制。以大尺度、中尺度裂缝为约束条件,利用叠前方位各向异性反演技术识别小尺度的裂缝密度及方位,最终实现缝洞单元划分。通过对裂缝进行逐级识别,提高裂缝识别精度,有利于缝洞连通性分析和缝洞单元的合理划分。     

扩张型心肌病应用美托洛尔对QT间期离散度及室性心律失常的影响

目的：探讨美托洛尔治疗对扩张型心肌病患者心电图QT间期离散度及室性心律失常的影响。方法：168例DCM患者分为基础治疗组（A组,82例）及基础治疗加美托洛尔治疗组（B组,86例）,给予B组在基础治疗上加服美托洛尔25mg／tid,疗程12个月。治疗前后应用24h动态心电图和多普勒超声心动图,观测QTd、QTcd、HR、室性心律失常如室性早搏、非持续性室性心动过速的发生情况、左心室射血分数。结果：B组QTd、QTcd及室性心律失常发生率均较A组显著降低（P均〈0．01）,左室射血分数较A组明显提高（P〈0．01）,而HR、血压无明显变化fP〉0．05）。提示B组疗效明显优于A组。结论：DCM患者长期应用美托洛尔可显著降低QTd、QTcd及VA的发生率,改善心功能,改善预后。     

废旧锌锰电池中汞的去除和回收实验

利用低温焙烧的方法去除废旧锌锰电池中的汞,研究了温度及时间对废旧锌锰电池中汞去除的影响。实验结果表明,在温度为400℃,焙烧90min时汞的去除率可达99％以上,汞回收率可达95％以上。     

用复合诱导型骨修复材料修复兔桡骨缺损的实验研究

以不同的载药方式构建4种壳聚糖/聚羟基丁酸酯-羟基戊酸酯(PHBV)复合诱导型骨修复材料,检测并比较4种支架材料对兔桡骨缺损的修复效果,筛选出最佳骨修复材料并确定最佳药物控释方式。以淫羊藿苷为诱导因子,采用两相混合冷冻干燥技术以微球载药、改性药物微球(W/O法制得并表征)、改性药物与材料共价结合等药物添加方式及不加药制得4种支架材料,并对其进行显微结构以及载药支架药物缓释表征,后将4种材料分别植入兔桡骨缺损处,于1、3、6个月进行X射线及三维CT观察支架材料对兔桡骨缺损的修复情况,HE,Masson染色观察其诱导成骨效果。结果表明,支架材料呈网络状串珠状的显微结构,载药微球粒径分布在3～11 μm,载药支架材料有着良好的药物缓释,其中共价结合组药物释放峰值时间较其他组推迟,为72 h,且峰值后药物缓释量迅速平稳为75 μg左右。X射线及三维CT观察显示,最终共价结合组支架材料骨缺损处连通,且骨密度高于其他3组。HE、Masson染色结果显示,共价结合组成骨效果优于其他组。共价结合的药物添加方式能使支架具有良好的药物缓释效果,进而对兔桡骨缺损表现出良好的修复效果。