基于小波域隐马尔可夫树模型的医学图像去噪

目的：为了更好地去除DR医学图像噪声。方法：通过分析其噪声来源,在小波去噪和小波域隐马尔可夫模型的基础上,进行改进,即引入了方差不变性变换来调整原始图像的噪声模型为高斯噪声模型;图像分解为不同频率的不同子带,而隐马尔可夫树模型则用来规划小波系数的边缘分布。结果：自然图像处理实验结果表明,与普通的小波去噪方法相比,该方法不但可以保留图像的边缘信息,而且能提高去嗓后图像的峰值信噪比。结论：同时用该方法处理DR图像．处理结果表明此方法在噪声去除、细节质量及骨骼锐化等方面比传统的高斯滤波及小坡阈值滤波等方法效果要好。     

A beta version of life: p110β takes center stage

The PI3K pathway is frequently activated in tumors, most commonly through p110α mutation or PTEN deletion. In contrast to p110α, p110β is oncogenic when over-expressed in the wild-type state, suggesting that its regulation by p85 is different than that of p110α. In this perspective, we summarize recent data concerning the regulation of p110β, which shows that wild-type p110β acts like an oncogenic mutant of p110α. We also discuss the significance of this altered regulation in tumor models of PTEN deletion, as well as the potential implications of the unique p110β regulation on GPCR-driven tumorigenesis.     

Human mesenchymal stem cells and their use in cell‐based therapies

The human population is increasingly facing various diseases, including types of cancer, that cannot be cured with conventional drugs. Advanced drug targeting of tumor cells is also often impossible when treating highly invasive and infiltrative tumors such as glioblastoma or pulmonary cancer, because of tumor cells' high migration and invasiveness. Pluripotent human mesenchymal stem cells (hMSCs) have been extensively studied, and strategies are being proposed for treating “incurable” cancers and injury/disease‐affected organs. Because of their own intrinsic properties, involving homing and immunomodulatory potency, hMSCs could be used as an excellent cell/drug delivery vehicle in those cell‐based therapies. Their unprecedented use has been shadowed, however, by their spontaneous transformation, which links them to cancer‐initiating cells during tumor development. How malignant initiation proceeds in vivo, and what are the exact characteristics of the cancer‐initiating cells, still remain to be investigated. In the present review, the authors summed up the most recent knowledge about hMSC characteristics, their malignant transformation, and outlined the possibilities of their safe use in novel cell‐based therapies. Cancer 2010. © 2010 American Cancer Society.     

三维动态增强MR血管成像对门静脉海绵样变性的诊断

目的分析门静脉海绵样变性（CTPV）在三维动态增强磁共振血管成像（3D—DCEMRA）上的表现和特征,并评价其诊断价值。方法回顾性分析了经临床及DSA检查证实的11例门静脉海绵样变性的3D—DCEMRA的特征性表现。结果本组11例CTPV中,门静脉主干闭塞见于6例,门静脉主干及左右支均受累者3例,单纯左支或右支闭塞2例。9例3D—DCEMRA清楚地显示了数条迂曲的侧支循环静脉跨过阻塞部位向肝内匐形延伸,其中7例可在网状扩张的门静脉腔内显示细条状、小点状低信号血栓影,6例清楚地显示门静脉全程多条细小迂曲的侧支循环静脉缠绕在一起,扭曲成网状的血管结构。结论3D—DCEMRA能准确地提供CTPV的位置、严重程度等信息,可直观地评价本病,为临床采取正确的治疗措施提供可靠依据。     

结晶型硫化镍诱发细胞恶性转化过程中基因组总体DNA甲基化的改变

Objective To observe the effect of crystalline NiS on genome DNA methylation profile in in vitro cultured cells.Methods 16HBE Cells were treated with crystalline NiS at 0.25,0.50,1.00 and 2.00 μg/cm2 for 24 h and three times at total.DAC treatment was given at 3 μmol/L for 72 h.5-mC immunofluorescence and SssI emthyltrasferase assay methods were applied to investigate if the hypomethylation of genome DNA involved.Results The results of 5-mC immunofluorescence showed that the fluorescence intensity of NiS-treated cells were decreased in some degree, and transformed cells were decreased dramatically.By the SssI methylase assay, an average of (81.9 ± 7.3 )% methylated CpG were found in negative control cells.By contrast, ( 77.9 ± 6.2) %, ( 75.3 ± 6.8 ) %, ( 59.5 ± 4.9 ) %, ( 67.4 ±5.1 ) % methylated CpG were observed in cells treated with NiS for three times at dosage of 0.25,0.50,1.00and 2.00 μg/cm2 which were abbreviated as NiS0.25, NiS0.50, NiS1.00, NiS2.00 respectively.The ANOVA analysis results showed that there was a significant difference in the 5 groups above ( F = 124.95,P ＜0.01 ).The results of Dunnett-t test showed that the methylated CpG of both group NiS1.00 and NiS2.00were significantly decreased compared with the negative control group(t values were 7.64,4.89 respectively,P ＜0.01 ).For methylated CpG, (46.2 ±4.1 ) % and (43.6% ±4.3)% were observed in NiS-transformed cells (NSTC1 and NSTC2) which were dramatically decreased compared with the negative control group(t values were 12.79,13.56 respectively, P ＜ 0.01 ).Conclusion Genomic DNA methylation levels were decreased during NiS induced malignant transformation.     

紫外线照射所致的DNA损伤对连接转化的影响

目的探讨DNA经不同波长紫外线照射与经紫外线照射不同时间所致损伤对基因库构建中DNA连接转化效率的影响。方法经改造的质粒DNA使用SfiI酶切过夜,1%琼脂糖凝胶电泳分离,在不同波长不同时间紫外线照射的条件下回收目的片断,并进行目的片断的连接转化,计数菌落数,计算转化效率。结果经302nm波长紫外线照射后,其连接转化的菌落数极少(60个/ngDNA),365nm波长紫外线照射条件下回收的DNA仍可被有效连接转化。在365nm波长紫外线照射下,与未经照射进行比较,当照射时间在30min,其连接转化成功率低于50%,而照射5min、15min的连接转化成功率仍高于70%,可满足大部分分子生物学实验的需要。回收的DNA连接转化的最大效率可超过20000个菌落/1ngDNA。结论在构建大容量基因库回收目的片断时,应避免紫外线的照射;在需要时,应选择在365nm波长紫外线照射条件下进行,且照射时间应尽量缩短,以不超过15min为宜。     

Comparison of Recurrence Rates with Contour-Loop Excision of the Transformation Zone (C-LETZ) and Large Loop Excision of the Transformation Zone (LLETZ) for CIN

Aim: To compare recurrence rates of large loop excision of the transformation zone (LLETZ) with those of contour-loop excision of the transformation zone (C-LETZ) in the management of cervical intraepithelial neoplasia (CIN). Materials and Methods: The medical records of 177 patients treated consecutively by LLETZ and C-LETZ for CIN at Rajavithi Hospital between 2006 and 2009 were retrospectively reviewed. Results: Of the 87 women in the C-LETZ group, 2 cases (2.30%) had recurrence compared with 13 cases (14.4%) of the 90 women in the LLETZ group, the higher recurrence rate in the latter being statistically significant (p<0.05). Median times of follow up in the C-LETZ and LLETZ groups were 12 months and 14 months respectively (p>0.05). The C-LETZ group showed less intraoperative bleeding compared to the LLETZ group, but the rate of achievement of single specimens and positive margins were similar in the two groups. Conclusions: The present study demonstrated the superiority of C-LETZ over LLETZ in terms of efficacy; C-LLETZ is associated with a lower recurrence rate and also carries a smaller risk of intraoperative bleeding than LLETZ. The rotatingtechnique still has a potential role in treating precancerous lesions of the cervix.     

卵巢子宫内膜异位症恶变与卵巢癌的相关性研究及预后分析

目的:探讨不同原因所致卵巢癌,尤其是是否由卵巢子宫内膜异位症(EMT)恶变而来的卵巢癌的临床病理及预后特征。方法:纳入2006年1月至2011年8月在四川大学华西第二医院病理检查确诊的有随访资料(术后随访时间2~89月)的EMT恶变者所致原发性卵巢癌患者49例为EMT恶变组,其病理类型为透明细胞癌、子宫内膜样腺癌及混合性腺癌;另选择非EMT恶变所致卵巢癌并与EMT恶变者具有相同组织学类型的卵巢癌患者188例为非EMT恶变组,比较两组卵巢癌的临床病理特征及预后特征。结果:1与非EMT恶变组比较,EMT恶变组在40岁人群中所占比例较大、CA125更多表现为正常而非升高、FIGO分期早期病例比例更多、透明细胞癌及子宫内膜样腺癌这两种病理类型的比例较高,两组差异有统计学意义(P0.05)。2单因素预后分析:EMT恶变所致透明细胞癌的生存率明显高于非EMT恶变所致透明细胞癌(P=0.010),是否由EMT恶变对子宫内膜样腺癌及混合性腺癌的预后影响不确切(P0.05)。3多因素COX回归分析:EMT恶变、手术满意度及FIGO分期是影响预后的独立危险因素。结论:EMT恶变所致卵巢癌病理类型主要包括透明细胞癌和子宫内膜样腺癌,EMT恶变是卵巢癌预后的独立影响因素,EMT恶变患者年龄相对较年轻、FIGO分期相对较早,尤其对透明细胞癌而言,EMT恶变的患者可能拥有更好的预后。     

基于小波和卡尔曼平滑的事件相关电位单次提取

本研究提出一种事件相关电位单次提取方法,可有效减少实验次数,并可探索实验之间ERP的变异性。此方法基于小波和卡尔曼平滑,首先利用小波变换考察ERP平均信号的时频特性,根据ERP不同分量出现的时间位置,在不同尺度上选取特定的单次实验ERP小波系数构成观测向量,其为真实ERP小波系数状态向量与噪声之和,然后对观测向量进行卡尔曼平滑,最后对卡尔曼平滑后的小波系数进行小波重构,得到单次提取的ERP信号。仿真实验表明,基于小波和卡尔曼平滑的方法不仅信噪比提高约16~18 dB,优于30次叠加平均、简单小波方法和基于高斯基函数的卡尔曼滤波方法,还可以跟踪ERP的幅度趋势变异性。与基于高斯基函数的卡尔曼滤波方法相比,所提方法降低了计算量。真实脑电ERP提取实验表明本方法较好地从单次记录中提取出了事件相关电位,并可解释ERP因适应和应激引起的趋势变异性。