基于核磁共振图像的脑肿瘤分割方法研究

利用脑肿瘤核磁共振(Magnetic resonance,MR)图像提供的关于肿瘤和脑组织的形状、大小与定位等信息准确地分割出脑肿瘤区域,对监测脑肿瘤患者的肿瘤生长或缩小、制定手术或放化疗计划都起着重要的作用.探讨了脑肿瘤MR图像分割的背景与意义,整理了脑肿瘤分割方法中常用的评估指标以及实验数据库的发展过程.基于脑肿瘤...     

肿瘤组织块接种法建立人脑肿瘤裸小鼠移植模型的研究

以脑肿瘤患者肿瘤组织块接种法建立三种人脑脑肿瘤裸小鼠移植模型，成功率为４２．８％。移植瘤在质地、血供、间质结构、生长特征等方面良好保持了原肿瘤特性，其直接、快速、稳定地建立模型的方法优于肿瘤细胞系接种法。较高的建模型成功率有赖于快速接种、较大接种量、长期观察、良好的净化条件等因素。     

核仁组成区嗜银蛋白定量对脑肿瘤诊断的意义

应用银胶染色技术对45例脑肿瘤细胞的核仁组成区嗜银蛋白(AgNOR)进行定量检测，结果发现良、恶性肿瘤之间的AgNOR计数差异有显著性，随着脑肿瘤病理分级的增高，AgNOR计数也增加，通过研究认为，脑肿瘤AgNOR计数对判断其生物学行为以及肿瘤诊断和预后均有重要意义。     

基于多模态3D-CNNs特征提取的MRI脑肿瘤分割方法

针对目前MRI脑肿瘤分割中的无监督特征提取方法无法适应脑肿瘤图像的差异性,提出一种基于多模态3D卷积神经网络(CNNs)特征提取的MRI脑肿瘤分割方法。将2D的多模态MRI图像组合成3D原始特征,通过3D-CNNs提取特征,更有利于提取各模态之间的差异信息,去除各模态之间的冗余干扰信息,同时缩小原始特征邻域大小,以适应同一病人不同图像层肿瘤大小的差异变化,进一步提高MRI脑肿瘤的分割精度。实验结果证明,能适应不同病人各模态之间的差异性和多变性,以提高脑肿瘤的分割精度。     

基于Web的脑肿瘤辅助决策系统的设计和实现

 随着磁共振图像和波谱在脑肿瘤诊断中的应用研究的日益增多,迫切需要建立数据库来存储管理大量的磁共振图像、波谱数据以及病人信息,并开发数据共享平台,为进一步的分析研究提供便利.本文采用MYSQL+Apache+PHP的B/S/S体系结构设计开发了一个基于Web的脑肿瘤诊断辅助决策系统,系统使用基于MVC模式的Zend框架,实现了用户信息管理,病人病历管理,磁共振图像和波谱数据的查询、下载、上传,脑肿瘤体积计算和位置显示等功能,为医生、波谱研究人员、三维重建人员提供了便利,为磁共振波谱对脑肿瘤的进一步研究奠定了基础,对远程医学资料共享和远程诊断具有实用价值.     

基于细胞自动机的脑部磁共振成像脑肿瘤分割方法

提出一种基于细胞自动机的脑肿瘤分割方法。首先通过人工交互输入一条线,使用细胞自动机模型对脑肿瘤图像进行分割,得到肿瘤图像的标号图,然后使用活动轮廓模型对标号图进行优化处理,除去非肿瘤像素点的干扰,得到更平滑的脑肿瘤轮廓。使用该方法在对比增强T1加权MRI脑肿瘤图像进行分割实验。实验结果表明,此方法能够很好地解决脑肿瘤分割过程中容易出现的不完全分割问题,分割准确率(Dice相似系数)可达到(94.07±1.58)%。     

基于细胞自动机的MRI脑肿瘤分割方法

提出一种基于细胞自动机的脑肿瘤分割方法.首先通过人工交互输入一条线,使用细胞自动机模型对脑肿瘤图像进行分割,得到肿瘤图像的标号图,然后使用活动轮廓模型对标号图进行优化处理,除去非肿瘤像素点的干扰,得到更平滑的脑肿瘤轮廓.使用该方法在对比增强T1加权MRI脑肿瘤图像进行分割实验.实验结果表明,此方法能够很好地解决脑肿瘤分割过程中容易出现的不完全分割问题,分割准确率(Dice相似系数)可达到(94.07±1.58)％.     

基于形态学滤波的标记分水岭脑肿瘤图像分割

针对MRI(magnetic resonance imaging)脑肿瘤图像受噪声、磁场和容积效应等影响难以准确分割的问题,提出了一种基于形态学滤波的标记分水岭分割方法.首先对脑肿瘤图像进行形态学梯度预处理;其次,梯度图像进行开闭重建滤波,既保留脑肿瘤梯度图像的轮廓信息,又去除噪声和局部极小区域;再次,采用扩展的极值变换和强制最小技术得到内部和外部标记符,利用这些标记符修正梯度幅度图像;最后,对叠加标记后的梯度图像进行分水岭变换.利用Matlab对类圆形、三角形等不同亮度与形状特点的3幅临床MRI脑肿瘤图像进行分割仿真测试,实验结果表明,该算法有良好的分割精度和速度.     

貌似炎性脑病的脑肿瘤临床分析

报告的 7例患者均在病前有“感冒”病史 ,临床症状、体征及脑脊液检查均符合脑炎或脑膜炎 .最后经病理学和头部CT以及脑脊液细胞学检查证实为脑肿瘤 .提示感冒只能看作是一切疾病可能病因 ,不能作为炎性脑病的主要病因     

貌似炎性脑病的脑肿瘤临床分析

报告的7例患者均在病前有"感冒"病史,临床症状、体征及脑脊液检查均符合脑炎或脑膜炎.最后经病理学和头部CT以及脑脊液细胞学检查证实为脑肿瘤.提示感冒只能看作是一切疾病可能病因,不能作为炎性脑病的主要病因.     

Directing neural stem cell fate with biomaterial parameters for injured brain regeneration

The discovery of neural stem cells (NSCs), which have the ability to self-renew and differentiate into all types of neural lineages, offers promising prospect for the treatment of brain neurological disorders such as stroke/cerebral ischemia, traumatic brain injury and neurodegenerative disorders. However, only limited number of NSCs could survive or propagate due to tissue inflammation or blood-brain barrier. Therefore, it is necessary to develop an appropriate culture system that highly mimics the natural NSCs niche to direct stem cell fate and behavior for nerve regeneration. Both biophysical and biochemical properties of the NSC niche, including topology, mechanical properties, bioactive molecules, and their spatial and temporal presentations should be considered for the design of functionalized scaffolds, which could not only serve as the delivery vehicles of NSCs but also stimulate specific cellular responses at the molecular level, such as support endogenous or exogenous cells proliferation, migration and homing, even promote the growth of axon at the injured brain site. This review attempts to outline the varieties of biomaterial     

脑干出血的CT表现与临床分析

目的 研究脑干出血的CT诊断价值。方法 运用影像学CT检查。结果 脑干出血CT表现为脑干高密度出血及血肿影。结论 CT能确定出血部位和累及范围。     

Changing potency by spontaneous fusion

Recent reports have suggested that mammalian stem cells residing in one tissue may have the capacity to produce differentiated cell types for other tissues and organs 1-9. Here we define a mechanism by which progenitor cells of the central nervous system can give rise to non-neural derivatives. Cells taken from mouse brain were co-cultured with pluripotent embryonic stem cells. Following selection for a transgenic marker carried only by the brain cells, undifferentiated stem cells are recovered in which the brain cell genome has undergone epigenetic reprogramming. However, these cells also carry a transgenic marker and chromosomes derived from the embryonic stem cells. Therefore the altered phenotype does not arise by direct conversion of brain to embryonic stem cell but rather through spontaneous generation of hybrid cells. The tetraploid hybrids exhibit full pluripotent character, including multilineage contribution to chimaeras. We propose that transdetermination consequent to cell fusion 10 could underlie many observations otherwise attributed to an intrinsic plasticity of tissue stem cells 9.     

Unique astrocyte ribbon in adult human brain contains neural stem cells but lacks chain migration

The subventricular zone (SVZ) is a principal source of adult neural stem cells in the rodent brain, generating thousands of olfactory bulb neurons every day. If the adult human brain contains a comparable germinal region, this could have considerable implications for future neuroregenerative therapy. Stem cells have been isolated from the human brain, but the identity, organization and function of adult neural stem cells in the human SVZ are unknown. Here we describe a ribbon of SVZ astrocytes lining the lateral ventricles of the adult human brain that proliferate in vivo and behave as multipotent progenitor cells in vitro. This astrocytic ribbon has not been observed in other vertebrates studied. Unexpectedly, we find no evidence of chains of migrating neuroblasts in the SVZ or in the pathway to the olfactory bulb. Our work identifies SVZ astrocytes as neural stem cells in a niche of unique organization in the adult human brain.     

一步法快速分离鉴定肿瘤干细胞的单细胞微流控芯片

应用多层软光刻技术, 以聚二甲基硅氧烷（PDMS）作为芯片材料, 制作一种新型的可用于单细胞鉴定研究的微流控芯片（60 mm×40 mm×4 mm）. 将肺癌细胞A549无血清悬浮培养富集肿瘤干细胞, 制成单细胞悬液, 与逆转录 聚合酶链式反应(RT PCR)的反应液混合后通入芯片, 细胞随机分布在2 048个微腔室中裂解并进行RT PCR. 该芯片集细胞捕获、 分离、 裂解及聚合酶链式反应(PCR)于一体, 实现了一步法快速鉴定肿瘤干细胞的目的, 通过统计阳性小室数可计算出肿瘤细胞中肿瘤干细胞的比例.     

MRI及1H-MRS鉴别脑肿瘤术后损伤、残留及复发的临床研究

论述磁共振增强成像(MRI)和氢质子磁共振波谱分析(1H-MRS)对脑肿瘤术后诊断和鉴别诊断的精确性,鉴别肿瘤损伤、残留或复发的临床研究.     

Identification of human brain tumour initiating cells

The cancer stem cell (CSC) hypothesis suggests that neoplastic clones are maintained exclusively by a rare fraction of cells with stem cell properties. Although the existence of CSCs in human leukaemia is established, little evidence exists for CSCs in solid tumours, except for breast cancer. Recently, we prospectively isolated a CD133+ cell subpopulation from human brain tumours that exhibited stem cell properties in vitro. However, the true measures of CSCs are their capacity for self renewal and exact recapitulation of the original tumour. Here we report the development of a xenograft assay that identified human brain tumour initiating cells that initiate tumours in vivo. Only the CD133+ brain tumour fraction contains cells that are capable of tumour initiation in NOD-SCID (non-obese diabetic, severe combined immunodeficient) mouse brains. Injection of as few as 100 CD133+ cells produced a tumour that could be serially transplanted and was a phenocopy of the patient's original tumour, whereas injection of 10(5) CD133- cells engrafted but did not cause a tumour. Thus, the identification of brain tumour initiating cells provides insights into human brain tumour pathogenesis, giving strong support for the CSC hypothesis as the basis for many solid tumours, and establishes a previously unidentified cellular target for more effective cancer therapies.     

Adult neural stem cells-Functional potential and therapeutic applications

The adult brain has been thought traditionally as a structure with a very limited regenerative capacity. It is now evident that neurogenesis in adult mammalian brain is a prevailing phenomenon. Neural stem cells with the ability to self-renew, differentiate into neurons, astrocytes and oligodendrocytes reside in some regions of the adult brain. Adult neurogenesis can be stimulated by many physiological factors including pregnancy. More strikingly, newborn neurons in hippocampus integrally function with local neurons, thus neural stem cells might play important roles in memory and learning function. It seems that neural stem cells could transdifferentiate into other tissues, such as blood cells and muscles. Although there are some impediments in this field, some attempts have been made to employ adult neural stem cells in the cell replacement therapy for traumatic and ischemic brain injuries.     

Glioma stem cells promote radioresistance by preferential activation of the DNA damage response

Ionizing radiation represents the most effective therapy for glioblastoma (World Health Organization grade IV glioma), one of the most lethal human malignancies, but radiotherapy remains only palliative because of radioresistance. The mechanisms underlying tumour radioresistance have remained elusive. Here we show that cancer stem cells contribute to glioma radioresistance through preferential activation of the DNA damage checkpoint response and an increase in DNA repair capacity. The fraction of tumour cells expressing CD133 (Prominin-1), a marker for both neural stem cells and brain cancer stem cells, is enriched after radiation in gliomas. In both cell culture and the brains of immunocompromised mice, CD133-expressing glioma cells survive ionizing radiation in increased proportions relative to most tumour cells, which lack CD133. CD133-expressing tumour cells isolated from both human glioma xenografts and primary patient glioblastoma specimens preferentially activate the DNA damage checkpoint in response to radiation, and repair radiation-induced DNA damage more effectively than CD133-negative tumour cells. In addition, the radioresistance of CD133-positive glioma stem cells can be reversed with a specific inhibitor of the Chk1 and Chk2 checkpoint kinases. Our results suggest that CD133-positive tumour cells represent the cellular population that confers glioma radioresistance and could be the source of tumour recurrence after radiation. Targeting DNA damage checkpoint response in cancer stem cells may overcome this radioresistance and provide a therapeutic model for malignant brain cancers.