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1. chinaXiv:201803.00958 [pdf]

PIK3CA and AKT2 mutations of gastric cancer in China

wenxiang cheng
Subjects: Biology >> Genetics

Mutations in PI3K and/or AKT have been reported in a variety of cancers. This indicates that the two pathways interact to cause cancer. We have therefore investigated their roles in gastric cancer (GC) in China. In our study, exons 9, 18 and 20 of PIK3CA gene and exons 6~14 of AKT2 gene were screened in 10 GC cell lines and 100 advanced primary GC together with matched normal tissues. Denaturing high performance liquid chromatography (DHPLC) and DNA sequencing were used to analyze the mutations in the two genes. Two point mutations in the PIK3CA gene were identified in 4 of 10 GC cell lines and in 4 of 100 GC primary tumors. Two polymorphisms in AKT2 were detected in 19 of 100 GC primary tumors. One point mutation in AKT2 was detected in 1 of 10 GC cell lines and 3 of 100 GC primary tumors, and no hot spot variation was detected. Our results indicate that PIK3CA and AKT2 mutations are found in GC, although not a common event, therefore they might still play an important role in mediating kinase activities towards gastric carcinogenesis.

submitted time 2018-03-16 Hits1855Downloads936 Comment 0

2. chinaXiv:201803.00577 [pdf]

Effects of tetracyclines on bone: an ambiguous question needs to be clarified

wenxiang cheng
Subjects: Biology >> Biochemistry

Tetracyclines have been widely used in bone histomorphometry to label new bone formation and apposition rate. However, most studies of tetracyclines have also shown their strong inhibitory action on osteoclasts and their effects on osteoblast activities as well. To even obtain the in-depth understanding on this issue, we have reviewed related studies in “Pubmed” by searching the keywords “tetracyclines and osteoclast”, “tetracyclines and osteoblast”, which retrieved 115 and 159 related documents, respectively. Among these papers, some described the application of tetracyclines as fluorescent marker in bone histomorphometry, while others discussed their role in protection of bone metabolism partly through inhibiting osteoclastogenesis or bone resorption and through enhancing osteogenesis. Based on the above mentioned, it seems that tetracyclines used as bone labeling markers may affect the results of bone histomorphometry to some extent. To even confirm the effect of tetracyclines on bone cells (osteoblast, osteoclast) and in vivo bone remodeling, related research work has been performed in our research team which indicated quite different results in vivo and in vitro. Therefore, the influence of tetracyclines on bone may differ in terms of different conditions which need to be further elucidated as well.

submitted time 2018-03-15 Hits2169Downloads899 Comment 0

3. chinaXiv:201803.00583 [pdf]

基于静息态fMRI的催眠控制呼吸研究

刘燕君; 李荣茂; 臧珊珊; 陈思宇; 谢耀钦
Subjects: Biology >> Neurobiology
Subjects: Engineering and technical science >> Biomedical Engineering

催眠是一种被证明有效的、无害的心理学上的呼吸控制方法。文章通过对 13 位有催眠背景的心理咨询师被试进行催眠控制呼吸实验,由催眠师引导被试进行催眠,运用静息态功能磁共振的方法来研究催眠控制呼吸状态下脑功能的异常。结果显示:在催眠状态下,脑活动在视觉皮层(枕叶)、感觉运动皮层(中央前回、中央后回、布洛德曼 4、6 区)、后扣带回以及颞中回上升;在背外侧前额皮层、小脑后叶以及缘上回下降,并且在全脑大规模静息态功能网络范围内相关关系增强(正常态 r=0.64,催眠态 r=0.80)。此外,催眠状态下视觉皮层与运动皮层之间的功能连接增强。研究结果表明,视觉皮层和运动皮层在催眠控制呼吸的神经机制中发挥了重要的作用,其神经机制也可能与认知处理和感知处理密切相关。本研究结合了心理学以及脑科学进行了研究,为催眠的研究提供了一个认知脑科学的研究新视觉。

submitted time 2018-03-15 Hits4216Downloads2281 Comment 0

4. chinaXiv:201803.00582 [pdf]

一种基于ROEWA算子的改进CV模型用于乳腺超声图像分割

刘磊; 温铁祥; 秦文健; 李凌; 辜嘉
Subjects: Biology >> Bioengineering

基于区域的几何活动轮廓(Chan-Vese, CV)模型是乳腺超声图像常用的一种分割算法。但传统的CV模型不能满足乳腺超声图像分割精度高、速度快的要求。因此,文章提出了一种基于指数加权平均比率(Ratio of Exponential Weighted Average,ROEWA)算子改进的CV模型,用于乳腺超声图像中病灶区域的分割。首先,计算乳腺超声图像的ROEWA算子。其次,基于图像的ROEWA算子构建边缘指示函数,用于代替CV模型中的Dirac项。最后,去除平滑项,从而提高曲线演化的速度。实验结果表明,文章提出的算法不仅能提高分割的精度,而且能显著提高分割的速度。

submitted time 2018-03-15 Hits1606Downloads921 Comment 0

5. chinaXiv:201803.00567 [pdf]

生物阻抗技术在手臂红外治疗中的初步应用研究

顾陈磊; 刘宇航; 李景振; 王磊; 聂泽东
Subjects: Biology >> Bioengineering

红外理疗采用红外光对人体部位进行照射,已在各种疾病的辅助治疗中得到了广泛的应用。红外理疗效果一般由医护人员的经验进行定性评估,目前鲜有关于红外理疗效果定量分析的报道。鉴于理疗身体部位血流信息的变化能反映红外理疗效果,实现无创、安全、实时监测红外理疗过程中的血流信息,将有助于引导红外理疗的疗程安排,提升红外理疗效果。文章提出了一种基于生物阻抗的方法来对手臂血流红外理疗效果进行评估。首先,选用BIOPAC生理信息记录仪为系统核心,利用二电极法测量人体心电信号,四电极法同步测量人体手臂在红外光照射前、中、后的生物阻抗变化;其次,通过小波变换进行基线漂移去除与特征提取分析,并运用朴素贝叶斯模型对特征点的稳定性进行评估。实验结果表明:手臂生物阻抗信号特征频率与心率变化趋势相同,平均数值误差在0.09%~1.60%;经红外光照射后,手臂生物阻抗单周期信号内次级波与主波比值上升,幅度为3.91%~13.05%,即生物阻抗信号能够反应手臂血流信息,且具有感知红外理疗过程中血流变化的灵敏性。

submitted time 2018-03-14 Hits1992Downloads1095 Comment 0

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