Cytochrome oxidase subunit II mRNAs in Oenothera mitochondria are edited at 24 sites

Summary Analysis of cDNA clones covering the entire coding region of cytochrome oxidase subunit II in Oenothera mitochondria reveals 24 potential editing sites: 23 C to U transitions and one U to C conversion. One editing event is observed outside the open reading frame in the 3 non-coding region. Thirteen editing sites are found altered in all cDNA clones, whereas the other eleven sites are only edited in some of the cDNA clones. These differentially edited sites occur most frequently at silent codon positions or in triplets at non-conserved amino acids.     

正常青少年628例用力呼气MTT和MTT_P的分析

作者用“直接法”对成都市正常男女青少年628例作了肺量图平均通过时间(MTT)和部分平均通过时间(MTTp)测定与分析。结果表明:MTT和MTTp均随其年龄增长而加大,并随肺内容积衰减而延长;用力肺活量-时间曲线并非单指数函数;比平均通过时间与年龄呈高度负相关,能反映肺弹性回缩压和气道传导率在青少年期间的增长情况。     

不规则对象的造型与分析

本文根据不规则对象轮廓的曲率变化以及局部形心位置,提出一套建立三维模型的数学方法,为设计与分析该对象奠定良好的基础。本文已将此方法应用于医学领域的临床工程上,成功地进行了人体中最复杂的硬组织之一,全牙列下颌骨的三维实体造型与力学分析,同时也为在其他领域形状复杂对象的设计与分析提供了一条思路。     

用邻域运算从CT图像中分割骨骼

阈值法是传统的从CT图像中分割骨骼的方法，但由于部分体积效应，这种方法难以分割骨骼的细小部分。本方法定义了邻域相关度的概念，用来描述体素在其26-邻域内与某种组织的相关程度。在文中，一种利用邻域运算的骨骼分割方法被提出，首先取一个较大的初始阈值，分割出骨骼体素，再选取一个下限阈值，灰度位于初始阈值和下限阈值间的体素被定义为模糊体素，用邻域运算计算每一个模糊体素对骨骼和对其它组织的邻域相关度，比较二者的加权值，以判断此体素可否转化为骨骼体素。循环搜索所有模糊体素，直到不能从模糊体素中转化出骨骼体索为止。这种方法能分割骨骼的细小部分，对初始阈值不敏感，具有良好的稳定性。     

基于偏最小二乘回归法分析药用紫草抗肿瘤谱效关系

目的 研究药用紫草高效液相色谱-质谱-多反应监测(UHPLC-QTRAP-MS/MS(MRM)特征轮廓谱与抗肿瘤活性的谱效关系,为明确紫草抗肿瘤作用物质基础提供依据.方法(2018年5月至2019年12月,数据来源于嘉应学院医学院客家药用生物资源研究所)采用UHPLC-QTRAP-MS/MS(MRM)技术建立药用紫草的特征轮廓谱,以A549细胞抑制率为药效指标,采用偏最小二乘回归法分析其谱效关系,并对部分化合物进行活性验证.结果 分析辨识了24个与紫草抗肿瘤作用具有重要影响的成分,其作用相关性由高到低依次为峰59、9、66、32、62、45、46、58、43、71、13、63、41、44、5、39、34、65、49、21、12、3、22和60.验证结果显示紫草呋喃A(19.86±0.55)μmol/L、紫草素(1.10±0.05)μmol/L、紫草呋喃E(22.60±0.92)μmol/L、乙酰紫草素(2.53±0.11)μmol/L、去氧紫草素(5.43±0.24)μmol/L、异丁酰紫草素(2.16±0.10)μmol/L、β,β-二甲基丙烯酰紫草素(3.50±0.16)μmol/L和α-甲基丁酰紫草素(0.74±0.03)μmol/L对A549细胞均有一定抑制作用,其IC50值为0.74～22.60μmol/L,而阳性药紫杉醇的半数抑制浓度(IC50值)为(3.45±0.16)μmol/L.结论 紫草的抗肿瘤药效是多种成分共同作用的结果,该研究初步明确了紫草抗肿瘤药效物质基础,为紫草后续研究和开发提供了科学依据.     

基于偏最小二乘法关联分析栀子不同炮制品化学成分与肝肾毒性

目的 基于偏最小二乘回归法（PLS）研究栀子不同炮制品化学成分与肝肾毒性的关联度。方法 采用超高效液相色谱法测定生栀子、炒栀子、姜栀子、焦栀子、栀子炭不同炮制品中栀子苷、京尼平龙胆双糖苷、栀子苷酸、去乙酰车叶草酸甲酯、西红花苷I和西红花苷Ⅱ 6种化学成分的含量,栀子不同炮制品水提液（7.5 g/kg）连续3 d大鼠ig给药,测定各组大鼠血清丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、总胆红素（TBIL）、血清肌酐（CREA）、尿素氮（BUN）的含量,使用Origin 9.1软件中的PLS算法分析栀子不同炮制品化学成分与肝肾毒性的关联度。结果 栀子炮制后栀子苷、西红花苷I和西红花苷Ⅱ的含量不同程度的降低,京尼平龙胆双糖苷、去乙酰车叶草酸甲酯和栀子苷酸含量在部分炮制品中升高;栀子及炮制品对正常大鼠可造成不同程度的肝、肾损伤（生栀子>炒栀子>姜栀子>焦栀子>栀子炭）;PLS分析表明6种主要化学成分中栀子苷与西红花苷I的变量重要性值均超过0.8。结论 栀子苷与西红花苷I可能是栀子肝肾毒性的物质基础,通过炮制降低栀子肝肾毒性的作用可能与炮制后栀子苷与西红花苷I含量降低有关。     

Secondary analysis of case-control association studies: Insights on weighting-based inference motivate a new specification test

Case-control sampling is frequently used in genetic association studies to examine the relationship between disease and genetic exposures. Such designs usually collect extensive information on phenotypes beyond the primary disease, whose associations with the genetic exposures are also of great interest. Because the cases are over-sampled, appropriate analysis of secondary phenotypes should take into account this biased sampling design. We previously introduced a weighting-based estimator for appropriate secondary analysis, but have not thoroughly explored its statistical properties. In this article, we revisit our previous estimator to offer new insights and methodological extensions. Specifically, we extend our previous estimator and construct its more general form based on generalized least squares (GLS). Such an extension allows us to connect the GLS estimator with the generalized method of moments and motivates a new specification test designed to assess the adequacy of the disease model or the weights. The specification test statistic measures the weighted discrepancy between the case and control subsample estimators, and asymptotically follows a central Chi-squared distribution under correct disease model specification. We illustrate the GLS estimator and specification test using a case-control sample of peripheral arterial disease, and use simulations to further shed light on the operating characteristics of the specification test.     

不同加工方法及材料制作部分贴面的边缘形貌分析

目的:比较采用粉浆堆塑工艺、热压铸造工艺及计算机辅助设计/计算机辅助制造(computer aided design/computer aided manufacturing,CAD/CAM)技术制作的不同材料部分贴面的边缘形貌。方法:选择无明显磨耗、龋坏,表面釉质光滑完整的人前磨牙30颗,随机分为5组,每组6颗,分别采用耐火代型粉浆堆塑工艺制作Noritake ^?长石质烤瓷部分贴面,热压铸造工艺制作IPS E.max Press部分贴面,CAD/CAM技术制作VITA Mark Ⅱ、VITA Supri-nity、VITA Enamic部分贴面。部分贴面试件粘接完成后,按照临床步骤进行边缘修整及抛光,获得在离体牙上粘接完成的部分贴面。通过肉眼观察、扫描电镜及色散能谱,记录并分析部分贴面边缘微观形貌及粘接剂暴露宽度。结果:不同加工方式及材料的部分贴面在粘接后经过修整、抛光,可获得肉眼可见的较光滑的材料表面及菲薄的刃状边缘。Noritake烤瓷组边缘较粗糙,粘接剂带状暴露量为(106.00±9.17) μm;E.max Press组边缘较平整,粘接剂暴露量为(138.33±20.59) μm;Enamic组边缘平滑,粘接剂暴露宽度较大,为(186.00±5.66) μm;Mark Ⅱ组与Suprinity组边缘虽有粗糙不平,但粘接剂暴露较少,分别为(50.67±7.51) μm及(65.67±17.90) μm;除Mark Ⅱ组与Suprinity组外,其余各组间差异均有统计学意义。结论:不同加工方法及材料制作的部分贴面,经过粘接、修整及抛光后,均可获得刃状边缘,但各组粘接剂有不同程度暴露,暴露量大小为Mark Ⅱ组/Suprinity组相似文献   

Robotic-assisted partial nephrectomy in duplicated collecting systems in the pediatric population: Techniques and outcomes

ObjectiveWe present our experience with pediatric robotic-assisted laparoscopic partial nephrectomy of a nonfunctioning moiety in a duplicated system (RALPN), comparing techniques and outcomes with those previously reported in the literature. To our knowledge, this is the largest series of this surgical procedure to date.Patients and methodsWe retrospectively reviewed all pediatric patients at our institution that had undergone RALPN from 2006 to 2012.ResultsTwenty-one patients underwent RALPN between 2006 and 2012. Mean patient age was 4.1 years. Mean operative time was 301 min. Mean estimated blood loss was 36 ml. Mean length of stay was 38 h. The majority of cases were performed with three laparoscopic ports. At initial follow-up ultrasound 6/21 (29%) demonstrated a fluid collection. The majority of these collections occurred in cases where the resection defect was not closed intraoperatively (42% of cases vs. 11% of cases). All fluid collections were asymptomatic and managed conservatively.ConclusionRALPN is associated with low complication rates. The robotic system allows for the use of only two small robotic working ports in most cases. Postoperative fluid collections may be prevented by formal closure of the polar defect, but fluid collections that do occur can be followed conservatively.