常染色体嵌合变异的流行病学分布及其影响因素研究进展

人类体细胞突变的发生和积累,又称体细胞嵌合现象。其中,嵌合染色体变异（mCA）对基因组完整性的影响最为显著,被视为人类衰老的表型之一。随着全球人口老龄化进程的加速,了解mCA的人群流行病学分布及其影响因素,有助于探索人体衰老进程中“基因组失稳”及其相关生物学机制,为人类年龄相关疾病的一级预防提供科学依据。本文旨在汇总既往大规模人群研究结果,对外周血常染色体mCA的人群流行病学分布及其影响因素进行综述。     

染色体全自动扫描仪在低比例嵌合体核型分析中的临床应用

目的通过两种方法比对,探讨染色体全自动扫描仪在Turner综合征低比例嵌合体核型检出率。方法取患者外周血进行淋巴细胞培养,常规染色体G显带技术核型分析,分析计数30个中期分裂相,分析5个核型,有异常者分析计数100个核型。结果2011年显微镜手工分析法对2211例患者染色体分析检出Turner综合征低比例嵌合体13例,阳性检出率为0．59％,2012年使用自动扫描仪系统分析法对3002例患者检出Turner综合征低比例嵌合体52例,阳性检出率为1．7％,同比检出率明显增加。结论常规显微镜核型分析是全手工操作,自行显微镜下找分裂相分析,一般都会选择比较完整的核型分析,低比例嵌合体不易发现。自动扫描系统建立了条件稳定,标准化要求的中期分裂相选择分析,提高了低比例嵌合体核型检出率。     

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目的探讨大肠癌血管新生、嵌合体血管(MV)与临床分期之间的关系及临床意义。方法对1999～2002北京朝阳医院消化科49例大肠癌患者的病变组织切片,用抗CD31单克隆抗体标记血管内皮细胞;用抗CEA单克隆抗体标记结肠癌细胞。经免疫组织化学双标染色检测患者瘤组织“热点”区域的微血管密度(MVD)、MV,并分析其与Dukes临床各期的关系。结果在不同Dukes分期的大肠癌组织标本中,MVD计数分别为B期43.98±21.46,C期59.54±26.95,D期70.80±19.04,表明大肠癌组织MVD随疾病分期的升高而增加,D期明显高于B期(P<0.01)。MV在B期占40.0%;C期占60.0%;D期占87.5%,表明MV随大肠癌的临床分期的增加而增加。经随访发现,随着大肠癌分期、MVD及MV的增加,患者生存率降低,生存期短。表明MVD与大肠癌的预后相关。结论大肠癌MVD及MV与疾病的分期及预后有关,提示临床对高MVD及MV患者应积极治疗。大肠癌血管新生及MV的存在为临床治疗提供了新的靶位点。     

A child with complementary mosaic trisomy 8 and mosaic trisomy 21; clinical description of Warkany-Down syndrome and mechanism of origin

Aneuploidy mosaicism involving two complementary different autosomal trisomy cell lines is extremely rare. Although a mosaic double trisomy 8/trisomy 21 has been described in literature, this is the first report of Warkany (+8)–Down (+21) syndrome due to two complementary mosaic trisomy cell lines. The phenotype of the male patient with Warkany–Down syndrome includes upslanting palpebral fissures, hypertelorism, small low-set ears with unilateral aural stenosis, large and broad hands and feet with deep palmar and plantar creases, bilateral cryptorchidism, generalized mild hypotonia and transient neonatal thrombocytopenia. At the age of two years, his developmental quotient is around 50. His height, weight and head circumference are below the third centile. We speculate on the mechanism of origin of the complementary trisomy cell lines based on molecular cytogenetic studies that showed no evidence for a chimera.     

中国10个地区成年人外周血嵌合染色体变异的流行病学分布特征

目的描述外周血嵌合染色体变异(mCA)在我国10个地区30～79岁自然人群的流行病学分布特征。方法纳入中国慢性病前瞻性研究(CKB)10个项目地区中已有基线数据(人口学特征、生活方式、体格检查等)和外周血基因分型数据的100 297名研究对象, 通过嵌合染色体变异工作流计算mCA表型检出率, 采用logistic回归比较mCA检出率在不同地区、不同特征人群间的分布差异。结果共检出5 810名mCA携带者, 检出率为5.8%, 标化后检出率为5.1%。mCA检出率随基线年龄增长逐渐升高, 30～、51～、>60岁人群检出率分别为3.4%、5.0%和9.4%(趋势检验P<0.001);男性检出率(8.0%)高于女性(4.0%), 城市检出率(6.4%)高于农村(5.3%), 差异均有统计学意义(P<0.001)。调整年龄、性别和10个地区后, 当前吸烟或因病戒烟者、低体力活动水平者mCA检出率较高, 肥胖者mCA检出率(5.3%)低于正常体重者(5.9%), 差异有统计学意义(P=0.006)。结论我国10个地区30～79岁自然人群的mCA检出率存在地区和人群分布差异。相...     

Progressive increase of the mosaic level for 45,X in 45,X/46, XX at different amniocenteses and postnatal progressive decrease of the 45,X cell line in a mosaic 45,X/46, XX fetus with a favorable outcome

ObjectiveWe present progressive increase of the mosaic level for 45,X in 45,X/46, XX at different amniocenteses and postnatal progressive decrease of the 45,X cell line in a mosaic 45,X/46, XX fetus with a favorable outcome.Case reportA 35-year-old, primigravid woman underwent amniocentesis at 16 weeks of gestation because of the advanced maternal age. Amniocentesis revealed a karyotype of 45,X [6]/46,XX [14]. Among 20 colonies of cultured amniocytes, six colonies had a karyotype of 45,X, whereas the other 14 colonies had a karyotype of 46,XX. Simultaneous array comparative genomic hybridization (aCGH) on uncultured amniocytes revealed the result of arr [GRCh37] (X) × 1 [0.42] (1–22) × 2. Prenatal ultrasound findings were unremarkable. Repeat amniocentesis at 33 weeks of gestation revealed a karyotype of 45,X [13]/46,XX [7]. Among 20 colonies of cultured amniocytes, 13 colonies had a karyotype of 45,X, whereas the other seven colonies had a karyotype of 46,XX. Simultaneous interphase fluorescence in situ hybridization (FISH) analysis on 100 uncultured amniocytes revealed that 44 cells had monosomy X consistent with 44% mosaicism for 45,X, whereas the rest cells had disomy X. At 38 weeks of gestation, a 2675-g phenotypically normal female baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 45,X [12]/46,XX [28], 45,X [12]/46,XX [28] and 46,XX [40/40], respectively. When follow-up at age three months, the neonate was normal in development. The karyotypes of peripheral blood was 45,X [4]/46,XX [36], and interphase FISH analysis on 100 buccal mucosal cells showed monosomy X in 11 cells consistent with 11% mosaicism for 45,X, whereas the rest cells had disomy X.ConclusionProgressive increase of the mosaic level for 45,X in 45,X/46, XX at different amniocenteses can be associated with a favorable outcome and postnatal progressive decrease of the 45,X cell line.     

对荷人脑胶质瘤裸鼠血管生成模式的研究

目的:探讨干细胞标志物ABCG2与肿瘤血管生成相关蛋白VEGF、CD34、VLA-2α在荷人脑胶质瘤裸小鼠移植瘤中的表达,同时运用CD34-PAS双染法观察移植瘤中的血供模式。方法:建立人脑胶质瘤裸小鼠皮下移植瘤模型30例。所有标本同时行HE染色和免疫组化检测,以正常人脑组织6例作为对照。光镜下检测上述基因的表达率和表达部位,并观察移植瘤中的血管生成模式。结果:ABCG2、VEGF、VLA-2α在移植瘤组织中阳性表达率均为100%,平均阳性细胞占有率分别为(3.93±1.438)%、(34.84±6.212)%、(30.33±4.428)%;CD34标记的微血管密度(MVD)计数平均达29.78±5.88个;内皮细胞被覆的血管、马赛克血管及拟态血管三种血供模式在移植瘤组织中均存在。结论:ABCG2高表达的细胞有亲血管分布趋向,VEGF、VLA-2α在移植瘤血管生成中起重要作用;恶性程度较高的移植瘤组织中存在着三种不同的血供模式。     

Edible safety requirements and assessment standards for agricultural genetically modified organisms.

This paper describes the background, principles, concepts and methods of framing the technical regulation for edible safety requirement and assessment of agricultural genetically modified organisms (agri-GMOs) for Shenzhen Special Economic Zone in the People's Republic of China. It provides a set of systematic criteria for edible safety requirements and the assessment process for agri-GMOs. First, focusing on the degree of risk and impact of different agri-GMOs, we developed hazard grades for toxicity, allergenicity, anti-nutrition effects, and unintended effects and standards for the impact type of genetic manipulation. Second, for assessing edible safety, we developed indexes and standards for different hazard grades of recipient organisms, for the influence of types of genetic manipulation and hazard grades of agri-GMOs. To evaluate the applicability of these criteria and their congruency with other safety assessment systems for GMOs applied by related organizations all over the world, we selected some agri-GMOs (soybean, maize, potato, capsicum and yeast) as cases to put through our new assessment system, and compared our results with the previous assessments. It turned out that the result of each of the cases was congruent with the original assessment.