MDM2启动子SNP309多态性与亚洲人群乳腺癌易感性关系的Meta分析

目的探讨MDM2基因启动子309位点多态性与亚洲人群乳腺癌易感性的关系。方法计算机检索Pub Med、EMBASE、Cochrane Library、中国期刊全文数据库、中国生物医学文献数据库、中文科技期刊数据库和万方数据库,收集MDM2基因SNP309多态性与亚洲人乳腺癌易感性关系的相关文献,然后用Stata软件进行亚组分析、敏感性分析和文献的发表偏倚检验。结果病例组和对照组相比,显性模型(GG+TG vs TT:OR=1.012,95%CI为0.56~1.83)、隐性模型(GG vs TG+TT:OR=1.10,95%CI为0.65~1.263)和等位基因模型(G vs T:OR=1.012,95%CI为0.81~1.83),共显性模型(GG vs TT:OR=0.86,95%CI为0.49~1.58),无统计学意义。结论在亚洲人群患者人群中,携带MDM2SNP309不会提高乳腺癌的发病风险。     

拟南芥基因组中注释为小檗碱桥环酶基因的分子克隆及异源表达

小檗碱桥环酶(BBE)催化(S)-牛心果碱((S)-reticuline)中N-CH3与分子内苄基部分中羟基的邻位芳香碳之间C-C键的形成,该酶属于双共价黄素蛋白家族,是苄基异喹啉类生物碱向小檗碱类生物碱转化的关键酶.迄今,在拟南芥(Arabidopsis thaliana)中尚未发现复杂生物碱,但其基因组测序结果表明拟南芥含有众多可能与复杂生物碱生物合成相关的基因,其中与BBE类似的基因有12个.基于与已知功能的BBE及拟南芥中BBE序列的分析,选定拟南芥中4个注释为BBE的编码基因为目的基因,设计特异引物,从拟南芥cDNA中扩增并克隆到pGM-T载体中,筛选重组子,测序并分析,获得了4个BBE目的基因,分别为AT2G34810、AT5G44400、AT5G44410和AT5G44440.将上述基因克隆至表达载体pET-28a或pET-30a中,分别转入大肠杆菌Rosetta(DE3)中,IPTG诱导实现了上述基因的异源表达.     

SLC26A4基因突变与耳聋

耳聋是最常见感觉障碍之一,与遗传关系密切.SLC26A4基因作为第二位的耳聋基因,与Pendred综合征(PS)和非综合征性聋DFNB4密切相关.SLC26A4基因突变主要与PS及DFNB4共同表现出的前庭水管扩大(EVA)相关,且不同种族及地区EVA患者该基因的突变频率及热点突变大不相同.SLC26A4基因的表现型与突变的类型关系不大,而是与等位基因数目相关.但目前SLC26A4基因突变的研究仍不完善.本文主要综述了近年来耳聋及SLC26A4基因的研究进展.     

中国汉族人群中Vav2基因和Vav3基因多态性与原发性闭角型青光眼之间关系的研究

目的本实验的目的是研究沌以和Vav3基因多态性与中国汉族人群中原发性闭角型青光眼（Prim aryangle-closure glaucoma,PACG）的遗传性是否有联系。方法211名原发性闭角型青光眼患者和206名性别和种族匹配的健康对照者纳入到本病例对照研究中。2个单核苷酸多态（the single nucleotide polymorphisms,SNPs）rs2156323（Vav2）和rs2801219（vav3）的基因分型用聚合酶链反应的限制性片段长度多态性分析（polymerase chain reaction restriction fragment length polymorphism,PCR—RFLP）。这两个基因位点的多态性与PACG遗传性之间的关系用卡方检验来评价。结果rs2156323（Vav2）和rs2801219（Vav3）的基因频率在所有参与者中均没有偏离哈迪一温伯格平衡（Hardy-Weinberg Equilibrium,HWE,P〉0．05）。该两个位点的等位基因频率和基因型频率的分布在PACG患者和正常对照者之间均没有差异。结论本研究的结果显示rs2156323和rs2801219可能不是中国汉族PACG的易感基因位点,Vav2和Vav3基因可能不是中国汉族PACG患者的易感基因。     

单碱基基因编辑系统的研究进展

基因编辑技术是近年来取得突破性进展的颠覆性技术之一。CRISPR/Cas9基因编辑系统简便、高效,被广泛应用于基因功能研究和利用。尽管CRISPR/Cas9可以高效靶向目的基因,但其定点修饰依赖于效率低下的同源重组机制,因此精准编辑基因的能力有待提高。单碱基编辑技术通过将Cas9切口酶或无核酸酶活性的Cas9与胞嘧啶脱氨酶形成融合蛋白,并通过sgRNA(单链向导RNA)将融合蛋白靶向靶位点,在不切割双链DNA的情况下对靶基因位点的单个碱基进行胞嘧啶C→胸腺嘧啶T或鸟嘌呤G→腺嘌呤A的精准编辑。目前,单碱基编辑技术已在植物、动物以及人细胞中进行了高效的基因定点突变,在农业、生物医学研究甚至基因治疗中有广泛的应用前景。本综述就单碱基编辑系统的发展和应用进行回顾和展望。     

美科学家确定下一组基因测序目标

美国科学家确定了基因测序的下一组目标生物,包括1种负鼠、4种真菌、3种蛔虫和1种甲虫。据英国《自然》杂志网站报道,这些生物的基因测序工作将于今年内在美国的5家研究中心展开,研究所由美国国家卫生研究所资助。此前,科学家已经绘制出了人类、小鼠、蜜蜂和果蝇等动物的基因图谱,目前正在对紫海胆、大鼠、黑猩猩和牛等进行测序。对比不同物种的基因组,有助于研究生物进化过程辨别基因并分析其功能,了解人类发育和疾病的机理。南美负鼠是一种灰色、短尾的小型哺乳动物,它将成为基因密码被破解的第一种有袋动物。研究人员选中负鼠是由于这种…     

64层螺旋CT血管成像对肠系膜上动脉活体形态的显示及临床应用

目的探讨64层螺旋cT血管成像（CTA）对肠系膜上动脉（SMA）活体形态的显示及临床应用价值。方法对80例临床疑有腹部、盆腔疾病的患者行64层螺旋CTA扫描,然后利用容积再现（VR）、多平面重建（MPR）、最大密度投影（MIP）、反向MIP（I—MIP）和薄层MIP（TS．MIP）等技术进行后处理。80例患者分为正常组（30例）和异常组（50例）两组,对正常组采用多种重建技术显示SMA各级分支,并测量SMA的直径,观察SMA起始段的走行;在MPR像上测量SMA与腹主动脉（AA）的夹角（An）,在左肾静脉（LRV）平面测量SMA至AA的距离（M）,在左侧肾门旁测量LRV最大前后径（A）,在SMA与AA问测量LRV最小前后径（B）。对异常组采用多种重建技术显示SMA,分析SMA特点。结果VR、MIP、I-MIP像均可显示正常组SMA整体解剖形态,TS-MIP对小分支显示优于其他重建技术。不同重建方式对SMA直径的测量无显著差异（F=0．71,P〉0．05）。SMA起始段走行方向为右下走行90％,前下走行占6．7％,左下走行占3．3％。An平均为（61．06±22．79）°。M平均为（14．62±4．00）mm,A平均为（9．16±1．91）mm,B平均为（6．00±2．01）mm,A与B比值〉2者占20．0％,〉3者占3．3％。异常组中有5例小肠先天性旋转不良及2例小肠扭转,SMA轴位像主要表现“回旋征”,VR表现为“螺旋征”;1例SMA分支栓塞;消化道肿瘤19例,其中8例供血动脉为SMA分支;回盲部动静脉畸形1例;余22例肝脏、泌尿生殖系统病变SMA无明显异常。结论64层螺旋CTA能很好地显示SMA的活体形态特征,具有重要的临床应用价值。     

天然掺杂铁氧体的电磁参数调控机制分析及其在吸波材料中的应用

对不同地质产状类型天然铁氧体的电磁参数测量结果发现, 岩浆岩型(A型)天然铁氧体的电磁参数明显区别于其他类型铁氧体, 是一种可用于微波吸收材料的天然矿物. 该矿物经选矿工艺制备后, 在8~12 GHz频率范围内, ε′ =58.60, ε″=10.0, μ′=1.2~1.5, μ″=1.0~1.2, 属于具有一定磁导率、低介电常数、高电磁损耗的磁性物质, 其粉体适合作为吸波材料的磁性吸收剂. 对A型天然铁氧体的矿物组成和化学成分的分析结果表明, 与单一磁铁矿或二元型铁矿物组成的天然铁氧体相比, A型天然铁氧体中的杂质元素和另相矿物含量明显高于其他天然铁氧体, 其中的杂质成分对电磁参数起着重要的调控作用, 这种调控作用有利于降低吸波材料的反射系数, 并提高电磁波吸收效率. 而且, A型铁氧体中的这种天然掺杂导致的结构缺陷及其对电磁参数的影响效应是人工制备的铁氧体难以实现的. 材料应用试验与吸波性能测量结果表明, 以A型天然铁氧体作为粉体填料与天然橡胶制成的吸波片材在8~12 GHz频率范围内的电磁波吸收频宽和反射系数均优于传统的羰基铁粉与橡胶制成的吸波片材, 完全可以替代羰基铁粉应用于微波吸收材料的开发, 而且具有原料丰富、制备工艺简单、成本低、吸波性能稳定的比较优势.     

人类基因组单体型图计划及其"中国卷"

国际人类基因组单体型图计划是针对亚、非、欧裔全基因组中的一百万或更多的单核苷酸序列差异位点进行测定和分析,构建出整合了人类遗传多态信息的每条染色体的“单体型图”,为疾病相关的基因研究提供全球共享的最基本数据。在这一多国参与的重大国际合作项目中,中国将做出10％的贡献,其具体内容为构建3号、21号染色体和8号染色体短臂的单体型图以及提供一半的亚洲样品。中国团队确定的平台技术有基于引物延伸方法的Sequenom的质谱检测系统和PerkinElmer的荧光偏振检测系统以及基于分子杂交原理的Illumina的光纤磁珠检测系统。     

稳定表达绿色荧光蛋白的B16细胞株的建立及其生物学特性研究

目的建立稳定表达绿色荧光蛋白的B16黑色素瘤细胞株,并研究其生物学特性。方法转染增强型绿色荧光蛋白基因入B16细胞,经G418联合单克隆培养,筛选阳性细胞。激光共聚焦荧光显微镜观察EGFP阳性细胞形态;流式细胞仪检测细胞内EGFP基因的蛋白表达;RT-PCR检测EGFP基因的mRNA表达;皮下接种及MTF法评价细胞在体内外的生长特性。结果流式细胞仪检测表达绿色荧光蛋白的细胞阳性率为99．81％,RT-PCR检测到EGFP基因的mRNA阳性表达。生长曲线显示其体外增殖趋势与B16相似,EGFP—B16体内成瘤速度较B16慢（P〈0．05）。结论稳定表达绿色荧光蛋白的EGFP—B16细胞株成功建立,可作为作为进一步研究恶性黑色素瘤的材料。     

Tolerance to cold and glucose homeostasis in adrenal demedullated dogs

Summary The rise in O₂ consumption and in glucose turnover, induced by acute cold exposure is not suppressed by adrenal demedullation in dogs. However, both at neutral and cold ambient temperature, the mean plasma glucose concentrations are higher in normal (N) than in adrenal-demedullated dogs (ADMX). In the cold, the fall in rectal temperature is larger in ADMX than in N dogs.This work was supported by a grant from Université Claude Bernard (U.E.R. Lyon Nord and U.E.R. Biologie Humaine).The authors thank D. Rougier and G. Dallevet for their excellent technical assistance and A. Brillant for secreterial assistance.     

Potentiative effects of sulfhydryl compounds on carrageenin-induced oedema in rats and relationship to their potencies as inhibitors of angiostin-coverting enzyme in vivo.

Carrageenin-induced oedema in rats was potentiated by oral administration of (4R)-3-[(2S)-3-mercapto-2-methylpropanoyl]-4-thiazolidinecarboxylic acid (SA291) and related sulfhydryl compounds, and the effect was closely correlated with their potencies as inhibitors of angiotensin-converting enzyme in vivo.     

Effect of epinephrine upon irreversible disposal and recycling of glucose in dogs

Summary Irreversible utilization and recycling of glucose during epinephrine-induced hyperglycemia were studied in adrenal-demedullated dogs exposed to neutral or cold ambient temperature. Whatever the ambient temperature, most of the extra glucose mobilized by epinephrine is recycled rather than irreversibly utilized by the peripheral tissues.This work was supported by a grant from Université Claude Bernard (U.E.R. Lyon Nord and U.E.R. Biologie Humaine).J. Schellhorn was on leave from the University of Chile. The authors thank D. Rougier and G. Dallevet for their excellent technical assistance.     

The sterols of two hadromerida sponges

Summary Sterols were extracted and identified from 2 marine sponges,Aaptos aaptos andSuberites domuncula. The sponges contained conventional C₂₆–C₃₀ sterols with a saturated ring system. Minor amounts of cholest-7-en-3-ol and cholesterol were also present. Cholestanol and 24-ethylcholestanol were the major components of the sterol mixtures.We thank Prof. L. Boniforti (Istituto Superiore di Sanità, Roma) for CG-MS analysis, Prof. R. Pronzato (Istituto di Zoologia dell'Università di Genova) for identifying the sponges and A. Senatore for G.C. measurements. This research was supported by grants of Ministero P.I. and C.N.R.     

Potentiative effects of sulfhydryl compounds on carrageenin-induced oedema in rats and relationship to their potencies as inhibitors of angiostin-converting enzyme in vivo

Summary Carrageenin-induced oedema in rats was potentiated by oral administration of (4R)-3-[(2S)-3-mercapto-2-methylpropanoyl]-4-thiazolidinecarboxylic acid (SA291) and related sulfhydryl compounds, and the effect was closely correlated with their potencies as inhibitors of angiotensin-converting enzyme in vivo.Acknowledgment. The authors wish to thank Prof. H. Fujimura, Department of Pharmacology, Gifu University School of Medicine, for his helpful advice.     

Regional distribution of pancreatic polypeptide cells in the 21-day fetal rat pancreas

Summary 21-day fetal rat pancreata were stained with the unlabeled antibody peroxidase-antiperoxidase technique using bovine pancreatic polypeptide as the primary antibody. Total counts of pancreatic polypeptide cells were made over the entire pancreas. It was found that the head region contained the greatest number of pancreatic polypeptide cells with the body next and the tail having the smallest number. The pancreatic polypeptide cells of the body were concentrated in the portion closest to the distal duodenum. This distribution pattern seems to support the suggested role of pancreatic polypeptide on the physiological function of the digestive tract.The authors wish to express their appreciation to Dr R. McEvoy, T. Whittlsey, G. Wassilchenko and D. Wilson for their assistance in this study. To whom reprint requests should be addressed.     

Persistence of infradian body weight cycles in castrated dormice (Glis glis)

Summary Male dormice were castrated at 2 phases of their infradian body weight cycles. No consistent changes were found in cycle period, amplitude, or absolute weights of the dormice following castration. Unlike other mammals, body weights of dormice appear unaffected by castration. Although both body weight and reproductive condition vary on an infradian basis, the changes in body weight appear to be programmed independently from changes in gonadal function.Acknowledgments. I would like to thank R. Melnyk, N. Mrosovsky, and J. D. Hallonquist for much helpful criticism and K. Lang and J. Kenyon for invaluable technical help. Research support was provided by a National Sciences and Engineering Research Council of Canada grant to N. Mrosovsky.     

Immunological blocking of exogenous and endogenous secretin in the dog

Summary In mongrel dogs with chronic gastric and duodenal fistula the biological activity of secretin on exocrine pancreatic secretion could be blocked by preincubating the secretin injected with rabbit antisecretin antibody. In addition, the activity of endogenous secretin released by acid was markedly reduced by application of antibody. Since no such effect was observed after testmeal stimulation, secretin is most probably not released in a significant amount by the liquid meal used in this experiment.This work was supported by grant No. 3.816-0.76 of the Swiss National Foundation for Scientific Research.We express our thanks to Miss G. van Hees, Mrs L. Jecker and Dr F. Meyer for their excellent technical assistance, Dr W. W. Rittmann for the surgical support, Dr G.A. Stalder for general advice, Dres R. Studer and D. Gillessen for providing secretin Roche, and Mrs C. Frei for secretarial work.     

An analysis of the distribution of the myelinated nerve fibers in the optic fascicle of a beagle dog

The composition of both optic fascicles of a Beagle dog was studied in topographically oriented, semithin transections of whole nerve stained with toluidine blue. About 165,000 myelinated fibers were present in each nerve, their maximum caliber reaching 11 micron; large, less densely arranged fibers occurred especially in the dorso-temporal region.     

Dog behaviour as related to spinal cord temperature

Summary 3 dogs could behaviourally modify their own spinal cord temperature (T_{spin. cord}). In a hot environment, 2 dogs did not cool their spinal cord, 1 dog warmed it. The higher the environmental temperature, the higher the chosen T_{spin. cord}. These results seem to imply that this latter dog tended, in warm environment, to behaviourally reduce: T_s>T_{spin. cord} (T_s mean skin temperature). Data obtained previously support this explanation.This experiment has been supported by the Centre National de la Recherche Scientifique (L.A. No. 181 C.N.R.S.) and by the Institut National de la Santé et de la Recherche Médicale I.N.S.E.R.M./A.T.P. No. 4-74-25).