胰腺内镜超声图像纹理特征提取与分类研究

提出了胰腺内镜超声图像的纹理特征提取与分类方法,可应用于胰腺癌内镜超声图像的计算机辅助诊断。对胰腺内镜超声图像采用数字图像处理算法提取9大类共69个纹理特征。使用类间距作为可分性判据,实现特征的初步筛选,之后使用顺序前进搜索算法进一步筛选特征,并由支撑向量机实现分类。对216例病例随机选取训练集和测试集,通过多次随机实验表明。本文提出的算法实现了较高的分类准确率,为胰腺癌的临床诊断提供有价值的参考意见。     

乳腺癌基因分型及其临床病理意义

乳腺癌是一类高度异质性的肿瘤,组织学类型、TNM分期都相同的肿瘤如采取相同的治疗方案,患者对治疗的反应和预后并不一致,这种差异被认为是由于肿瘤的分子差异所造成的。最近研究人员应用基因芯片技术,通过对乳腺癌基因表达谱的检测分析,提出了乳腺癌的5个基因亚型,即LuminalA、LuminalB、ERBB2＋、basal-like和normal-like亚型,初步研究显示乳腺癌的基因分型与病人的预后、化疗反应等具有更好的相关性。     

基于改进型组织特异纹理滤波器的乳腺肿瘤超声图像处理

基于乳腺超声图像的多参数纹理分类实验,改进了Gjenna Sfippel等的自适应纹理滤波器,通过引入模糊函数、增加重叠区域和迭代次数的措施,在减少图像噪声的同时,增强肿瘤与周围正常组织的视觉差别。量化比较乳腺超声图像经该滤波算法和几种常用滤波算法处理前后的的统计特征参量和肿瘤边缘检测的精确率,验证了该算法的有效性和优越性。     

PCDGF在乳腺癌中的表达及其对肿瘤血管生成的影响

目的:研究畸胎瘤细胞源性生长因子(PC cell-derived growth factor,PCDGF)的表达与乳腺癌血管形成的关系及其临床意义.方法:采用免疫组织化学的方法对130例乳腺手术标本中的PCDGF及其中70例乳腺癌组织中的血管内皮因子(vascular endothelial growth factor,VEGF)、微血管密度(mean microvessel density,MVD)的表达情况进行检测.结果:乳腺癌中PCDGF的表达显著高于非乳腺癌组织(P＜0.05).乳腺癌中PCDGF阳性组MVD水平明显高于阴性组(P＜0.01),VEGF阳性组MVD水平明显高于阴性组(P＜0.01),二者表达呈正相关(P＜0.05).o结论:PCDGF在乳腺癌中特异性表达,调节协同VEGF调控乳腺癌血管形成,有望作为乳腺癌早期诊断指标和抗血管治疗的新靶点.     

Evaluation of MCM-2 expression in TMA cervical specimens

Background

Minichromosome maintenance proteins (MCM) are highly expressed in actively replicating cells. The need for biological markers for cervical carcinoma and its precursor lesions is emerging. Our main aim was to determine the immunohistochemical expression of MCM-2 in HIV-positive and -negative dysplastic cervical specimens.

Methods

Immunohistochemical analysis of MCM-2 was performed in a total of 352 cervical TMA specimens of normal control, low-grade CIN, high-grade CIN and invasive tumor. 38 specimens were from HIV-positive women. A receiver operating characteristic (ROC) curve was constructed to determine the best cutoff to diagnose high-grade CIN and invasive cervical cancer.

Results

In the progression from normal epithelium to high-grade CIN and invasive tumor we found significant differences in the MCM-2 expression (p<0.05). Based on the ROC curve of 80% with an area under the curve (AUC) of 0.78, expression of MCM-2 to diagnose high-grade CIN and invasive tumor resulted in sensitivity of 81%, specificity of 66%, a positive predictive value (PPV) of 86% and a negative predictive value (NPV) of 57%. HIV-positive cervices revealed a decreasing expression of MCM-2 in both LGCIN and HGCIN compared with HIV-negative specimens (p<0.0001).

Conclusions

The present study suggests that immunohistochemical MCM-2 may not be a promising biomarker for diagnosing high-grade CIN and invasive cancer.     

转查尔酮合酶基因对烟草花色及花器官的影响

花色是重要的园艺性状,一直是育种工作者苦苦追求的目标。利用植物基因工程技术可定向改良花色。根据已知的CHS序列(序列号M20308.),用PCR方法从拟南芥中克隆CHS基因,并分别将其以正向、反向插入到真核表达载体pBI121,在农杆菌介导下用叶盘转化法转化烟草。对转基因烟草进行检测,结果表明,转基因烟草的花色变淡、花青素含量降低;叶片颜色变浅、叶绿素含量降低。转基因烟草花的形态也发生了明显变异。