共查询到20条相似文献,搜索用时 15 毫秒
1.
V. F. Ivanova 《Bulletin of experimental biology and medicine》1976,82(4):1573-1575
Absorption of hypotonic, physiological, and hypertonic solutions and of an ink suspension in physiological saline from the peritoneal cavity was studied by an electron-microscopic method. Pinocytosis was estimated quantitatively on electron micrographs. The passage of true solutions through the mesothelium was shown to take place diffusely through the cytoplasm of its cells and along the intercellular spaces, whereas the ink suspension passed only along open intercellular spaces. Pinocytosis in mesothelial cells takes place from the basal part toward the apex and is aimed at equalizing the concentration of the protein and salt composition of the serous fluid.Morphological Department, Central Research Laboratory, Leningrad Sanitary Hygiene Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR S. V. Anichkov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1258–1261, October, 1976. 相似文献
2.
Stereological Investigation of the Age‐Related Changes of the Myelinated Fibers in the Hippocampus of Male Rats
下载免费PDF全文
![点击此处可从《Anatomical record (Hoboken, N.J. : 2007)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lin Chen Xuan Qiu Chun‐Xia Huang Hong Wu Chen Li Jun‐Qing Yang Lei Zhang Feng‐Lei Chao Yong Tang 《Anatomical record (Hoboken, N.J. : 2007)》2014,297(8):1490-1497
The decline of hippocampus‐dependent learning and memory during normal aging is not associated with neuron death and synapse loss. Until now, age‐related changes in the myelinated fibers of the hippocampus have not been investigated. Therefore, in this study, the myelinated fibers in the hippocampi of young (6 months), middle‐aged (18 months), and old‐aged (28 months) male Sprague‐Dawley rats were studied with transmission electron microscope and stereological methods, following spatial learning tests in a Morris water maze. The results showed that hippocampus‐dependent spatial learning was impaired in old‐aged rats but that the total volume, length, and mean diameter of the myelinated fibers in the hippocampus, as well as the hippocampal volume, remained constant during the normal aging process. Our results suggest that the age‐related decline in hippocampus‐dependent spatial learning is not attributable to myelinated fiber changes in the hippocampus and that other, undetermined factors are responsible. Anat Rec, 297:1490–1497, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
3.
Forearm position matching tasks were performed by blindfolded subjects before and after applying vibration for 60 s to the biceps or triceps muscle of one arm. Following cessation of vibration, statistically significant alignment (proprioceptive) errors occurred when a movement lengthened the previously vibrated muscle. The error was such that the length of the post-vibrated muscle was greater than the length of the same muscle in the non-vibrated arm. This effect is the opposite to that which occurs during vibration. 相似文献
4.
Emiliano Bruner José Manuel De La Cuétara Ralph Holloway 《Anatomical record (Hoboken, N.J. : 2007)》2011,294(9):1548-1556
The parietal bones approximately cover the extension of the underlying parietal lobes. Although the boundaries of these two anatomical elements do not coincide, during morphogenesis the growth of the parietal bones is largely induced by the pressure exerted by the parietal lobes. Modern humans display larger parietal chords and arcs compared with non‐modern human species. However, the variation of these variables have not been analyzed before according to the covariation with the general endocranial diameters. When the curvature of the parietal bones is regressed onto the main neurocranial distances, modern humans show larger relative values, suggesting not only an absolute enlargement but a definite allometric change. Taking into account the morphogenetic relationships with the parietal lobes, these results further support previous hypotheses suggesting a relative enlargement of these cortical areas in Homo sapiens, by using simple and reliable homologous neurocranial arcs. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc. 相似文献
5.
A 71-year-old asbestos-exposed male with symptoms suggestive of asbestosis for the previous 8 years presented with abdominal distension and ascites. Clinically, a diagnosis of ? mesothelioma ? carcinoma was made. Light microscopy of an omental biopsy failed to advance the diagnosis: The tumor was a solid, papillary, and glandular neoplasm lacking mucin and hyaluronidase-sensitive Alcian blue staining material. Immunohistochemistry gave positive results for Ber-EP4, LeuM1, and CEA, markers, favoring carcinoma. Electron microscopy revealed processes in channels and lumina, which were long, slender, and uncoated with a length: diameter ratio of 19.7. A few possessed small rootlets. A glycocalyx and glycocalyceal bodies were not seen. Other features included tonofibrils, a basal lamina, and desmosomes. The patient died 3 months following the onset of abdominal symptoms. Autopsy findings included solid and papillary tumor throughout the peritoneum, but no intrinsic tumor of the gastrointestinal tract or elsewhere. Arriving at a final diagnosis was complicated by immunohistochemistry, which favored carcinoma, and ultra-structure, which suggested mesothelioma. Taking into account all lines of evidence, it was concluded that the tumor was probably a mesothelioma but one with some features developed to an extent more typical of carcinoma. 相似文献
6.
Chen Li Shu Yang Wei Zhang Wei Lu Jens R. Nyengaard John H. Morrison Yong Tang 《Anatomical record (Hoboken, N.J. : 2007)》2009,292(4):528-535
To determine the exact reason for the age‐related decline of the myelinated fiber length in white matter, we performed this study. In middle‐aged rats, there was age‐related loss of the unmyelinated fibers with large diameters. The demyelination of the myelinated fibers with small diameters in middle‐aged rat white matter might make the age‐related decrease of the unmyelinated fibers with small diameters in the white matter unnoticeable. However, in old‐aged female rats, the unmyelinated fibers with large and small diameters significantly degenerated together and that the unmyelinated fibers formed from the demyelination of the myelinated fibers could not replenish the age‐related loss of the unmyelinated fibers in the white matter. In conclusion, this study suggested that demyelination of myelinated fibers with small diameters in aged white matter might be the key mechanism of the significant decline of the myelinated fiber length in aged white matter. Anat Rec, 292:528–535, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
7.
8.
Koichi Tanaka Tetsu Hayakawa Seishi Maeda Sachi Kuwahara‐Otani Makoto Seki 《Anatomical record (Hoboken, N.J. : 2007)》2011,294(10):1736-1742
The distribution and the ultrastructure of afferent fibers innervating the parietal peritoneum in the rat was studied with immunohistochemistry using an antiserum against the neuronal marker protein gene product 9.5. The immunoreactive fibers were distributed throughout the peritoneum. They generally ran straight and parallel to the intercostal nerves running in the abdominal muscles underlying the peritoneum. They sometimes branched and terminated by forming club‐like endings. The number of nerve endings on the peritoneal surface was 3.25 ± 1.66 mm?2. Electron microscopic observations revealed both unmyelinated and myelinated nerve fibers. The unmyelinated fibers were thin and about 1 μm in diameter. Their endings formed slight swellings located just inside the peritoneal cell layer. The myelinated fibers often formed a bundle that was composed of two or three nerve fibers. Each myelinated fiber kept in contact with a Shwann cell and projected toward the peritoneal cavity. Finally, they penetrated the peritoneal cell layer to reach the peritoneal cavity. These fibers then made contacts with the peritoneal cells and became free from the myelin sheath. The ending had a club‐like shape covered with collagen fibers, and contained many neurofilaments, a few mitochondria, but no synaptic vesicles. These results suggest that since the sensory endings are exposed at the peritoneal cavity, the sensory fibers are highly sensitive to somatic or nociceptive stimuli. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc. 相似文献
9.
高阶神经网络用于心电信号的识别 总被引:4,自引:0,他引:4
心电图(ECG)的自动识别及分类长期以来一直是较难解决的问题,特别是当截取ECG信号的起点不同(相当于信号发生平移)及有基线漂移(相当于信号发生旋转)时,在不作预处理情况下要求仍能正确识别及分类,即要求识别过程具有平移不变性和旋转不变性,更是困扰生物医学工程上作者的困难问题之一。作者采用高阶神经网络(二阶),对五类(正常类、高R波类、高T波类、T波倒置类及心律不齐类)具有平移及旋转的ECG信号进行分类识别。结果表明,本网络具有较好的分类效果。平移信号不受任何限制,可任意平移,旋转信号最大旋转幅度为原信号的20%。本工作全部在微机上完成,而且本网还具有灵敏度高,学习时间短等特点,而有较大的临床实用价值。 相似文献
10.
《Ultrastructural pathology》2013,37(3):389-398
The desmoplastic small round cell tumor (DSRCT) has a predilection for involvement of the peritoneal surfaces of young adult men. The tumor has an extremely poor prognosis: despite aggressive therapy the patients usually die of disease within the first 2 years following diagnosis. The present report details the pathologic features of a pelvic tumor, which proved to be a DSRCT, arising in a previously healthy 24-year-old man. The light microscopic features were typical of a DSRCT—the tumor cells were small and round, had inconspicuous cytoplasm, and were grouped into distinctive islands and cords that were dispersed in a fibrous stroma. The immunohistochemical features were likewise characteristic of DSRCT in that the tumor cells were positive for cytokeratin, vimentin, epithelial membrane antigen, and desmin. Ultrastructurally, the tumor cells were distinguished by an abundance of intercellular junctions, cytoplasmic lipid droplets, cytoplasmic intermediate filaments, and an absence of surface microvilli. Recognition of this tumor type is important in view of both its clinical features (extremely poor prognosis despite therapy) and its potential to shed some light on the nature of the family of lesions that has traditionally been classified by light microscopists as small round cell tumors. 相似文献
11.
Intra-abdominal Desmoplastic Small Round Cell Tumor of the Peritoneum in a Young Man 总被引:2,自引:0,他引:2
Kenneth Devaney 《Ultrastructural pathology》1994,18(3):389-398
The desmoplastic small round cell tumor (DSRCT) has a predilection for involvement of the peritoneal surfaces of young adult men. The tumor has an extremely poor prognosis: despite aggressive therapy the patients usually die of disease within the first 2 years following diagnosis. The present report details the pathologic features of a pelvic tumor, which proved to be a DSRCT, arising in a previously healthy 24-year-old man. The light microscopic features were typical of a DSRCT—the tumor cells were small and round, had inconspicuous cytoplasm, and were grouped into distinctive islands and cords that were dispersed in a fibrous stroma. The immunohistochemical features were likewise characteristic of DSRCT in that the tumor cells were positive for cytokeratin, vimentin, epithelial membrane antigen, and desmin. Ultrastructurally, the tumor cells were distinguished by an abundance of intercellular junctions, cytoplasmic lipid droplets, cytoplasmic intermediate filaments, and an absence of surface microvilli. Recognition of this tumor type is important in view of both its clinical features (extremely poor prognosis despite therapy) and its potential to shed some light on the nature of the family of lesions that has traditionally been classified by light microscopists as small round cell tumors. 相似文献
12.
背景:通过眼底荧光血管造影(FFA)所得到的数字图像以及对其进行处理所得到的数据,可反映视网膜血管结构、血流动力学改变、血管病理生理变化及其相关结构的病理改变,广泛应用于视网膜、脉络膜及视神经疾病的鉴别诊断。目的:通过分析眼底造影图像和BP神经网络的特点,利用BP神经网络对眼底造影图像进行分割,并将其利用到眼科的临床辅助诊断之中。方法:将待分割图像区域分为背景和目标两类,用手工方法得到这两类的样本图像,提取样本图像的特征,如灰度、方差、纹理等;对提取的样本特征值进行归一化处理,输入神经网络分类器,利用BP训练算法进行训练;输入待分类的医学图像,提取图像特征,并进行归一化处理;将归一化后的特征值,输入已训练的神经网络分类器进行分类,得到眼底造影图像的分割结果。结果与结论:本文使用的眼底造影图像分割方法抗干扰能力强,分割的眼底造影图像清晰、内容丰富。可以为眼科医生的临床诊断提供较大帮助。 相似文献
13.
Molecular mechanisms underlying monosynaptic sensory‐motor circuit development in the spinal cord
下载免费PDF全文
![点击此处可从《Developmental dynamics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Motor behaviors are precisely controlled by the integration of sensory and motor systems in the central nervous system (CNS). Proprioceptive sensory neurons, key components of the sensory system, are located in the dorsal root ganglia and project axons both centrally to the spinal cord and peripherally to muscles and tendons, communicating peripheral information about the body to the CNS. Changes in muscle length detected by muscle spindles, and tension variations in tendons conveyed by Golgi tendon organs, are communicated to the CNS through group Ia /II, and Ib proprioceptive sensory afferents, respectively. Group Ib proprioceptive sensory neurons connect with motor neurons indirectly through spinal interneurons, whereas group Ia/II axons form both direct (monosynaptic) and indirect connections with motor neurons. Although monosynaptic sensory‐motor circuits between spindle proprioceptive sensory neurons and motor neurons have been extensively studied since 1950s, the molecular mechanisms underlying their formation and upkeep have only recently begun to be understood. We will discuss our current understanding of the molecular foundation of monosynaptic circuit development and maintenance involving proprioceptive sensory neurons and motor neurons in the mammalian spinal cord. Developmental Dynamics 247:581–587, 2018. © 2017 Wiley Periodicals, Inc. 相似文献
14.
Chen Li Shu Yang Lin Chen Wei Lu Xuan Qiu Hans Jorgen G. Gundersen Yong Tang 《Anatomical record (Hoboken, N.J. : 2007)》2009,292(10):1648-1655
In the present study, efficient and unbiased stereological techniques to investigate the myelin sheaths of the myelinated fibers in rat white matter were established. In the present design, four tissue blocks were obtained from the entire white matter of rat brain in a uniform, random fashion. Isotropic, uniform random (IUR) sections were ensured by the use of the isector technique. One section with the thickness of 60 nm was cut from the center of each epon block. Eight to 10 fields of vision were randomly photographed under a transmission electron microscope. The total length of the myelinated fibers and the total volume of the myelin sheaths in the white matter were the products of the length density, volume density, and the volume of the white matter obtained with the Cavalieri principle. The mean areas of the myelinated fibers profiles and myelin sheaths were estimated with the point counting technique. The inner and outer perimeters of the myelin sheaths were estimated by the use of a line grid, and the thickness of the myelin sheaths was estimated by direct orthogonal measurements in uniform, random locations. The described methods will provide very useful tools for future quantitative studies of changes in the myelin sheaths of white matter in various experimental conditions and in various neurodegenerative diseases. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
15.
反向传播(BP)神经网络在基因数据分析中具有重要意义。本文首先介绍了单核甘酸多态性(single nucleotidepolymorphisms,SNPs)的研究背景、分析热点及遇到的主要问题;在此基础上综述了当前常用的SNPs分析方法及其不足;随后介绍了BP神经网络在SNPs分析中的应用,如易感基因的筛选、肿瘤的诊断性分类等,并针对主要问题提出了解决方法,即用BP网络结合参数递减方法(parameter decreasing method,PDM)和聚类分析进行复杂疾病相关的SNPs数据分析。 相似文献
16.
鲍立峰 《中国医学物理学杂志》2008,25(2):606-609
目的:本研究将计算机技术与病理学专家的实际经验相结合,在采用图像处理技术对医学图像进行处理的基础上,应用人工神经网络分析卵巢浆液性囊腺肿瘤细胞核形态特征,并比较径向基函数网络与自组织网络两种算法。方法:对每个良性,交界性,或恶性卵巢浆液性囊腺肿瘤细胞及正常卵巢上皮组织细胞分别提取五个形态参数,用两种神经网络进行分类识别。结果:径向基函数训练步数少,但准确率没有自组织网络高。结论:应用神经网络进行细胞识别。在医学科研以及临床诊断方面有重要的现实意义和广阔的应用前景。 相似文献
17.
针对功能电刺激(FES)康复技术中肌肉的时变和高度非线性的特点,提出一种实时调整FES系统输出,实现康复患者自适应训练的方法。考虑到患者间和康复各阶段肌肉对电刺激响应能力的差异,利用神经网络良好的非线性逼近能力,采用神经网络辨识器辨识相关运动肌肉的FES模型,并在此基础上,利用神经网络控制器在线调节控制策略及刺激参数,提高FES系统的自适应能力。通过人体腕关节运动控制的FES实验,验证该方法具有较高的轨迹跟踪控制精度和较强的自适应能力。 相似文献
18.
基于人工神经网络的足月胎儿体重预测方法 总被引:2,自引:0,他引:2
对胎儿体重的预测在产科临床上具有非常重要的意义,传统上采用回归分析方法预测胎儿体重,存在可靠性差等缺点。本研究采用反向传播(BP)人工神经网络方法预测胎儿体重,实验中采用双顶径、小脑横径、腹围、肝脏长度、股骨长度、股骨皮下脂肪厚度、孕龄等参数作为BP神经网络的输入参数,网络由输入层、隐含层和输出层三部分组成。对109例临床资料进行预测,结果为:训练组预测符合率达89.77%,平均绝对误差104.22g,平均相对误差3.24%;验证组预测符合率达76.19%,平均绝对误差190.84g,平均相对误差5.60%。表明人工神经网络预测胎儿体重方法十分有效,准确性高于回归方程。 相似文献
19.
目的:探讨各种急症发病与气象条件的关系,建立基于人工神经网络的医疗气象预报模型,为预防和控制各种急症的发病提供科学参考。方法:收集济南市急救中心2007~2008年的急诊病例和同期天气资料,利用SAS9.0统计软件进行气象因素与各种急症发病人数的相关分析,利用Matlab7.0软件构建急症发病的BP人工神经网络预测模型,并对网络进行评价。结果:气象因素及其变化与各种急症的发病有密切关系。根据建立的人工神经网络模型预测显示,除CO中毒预测准确率较低外(46%),其余各类急症的预测准确率为76%~89%。结论:基于BP人工神经网络的急症医疗气象模型有较好的预测效果,具有进一步研究的价值。 相似文献
20.
目的研究人工神经网络在涂阴肺结核诊断中的应用。方法将全部研究对象随机分为建模样本和证实样本,再将建模样本分为训练样本及校验样本。利用训练样本筛选出对诊断涂阴肺结核有意义的单项参数指标来构建人工神经网络诊断模型,并用校验样本确定合适的网络结构,最后用证实样本评价其泛化能力。结果得到人工神经网络模型结构为(29-9-1).BP型。该模型在证实样本ROC曲线下面积为(0.989±0.015),诊断准确率为93.10%,灵敏度及特异度分别为88.89%及100%。结论(29-9-1).BP型网络模型可作为涂阴肺结核的诊断工具,有良好的泛化能力,值得进一步探讨。 相似文献