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81.
为探察人左心室壁心外膜区微血管的三维空间构型和形态计量学指标。本研究应用微血管腐蚀铸型/扫描电子显微镜技术和酶组化(碱性磷酸酶反应)染色方法,观察10例心脏标本,得出心外膜区的毛细血管直径为7.2±1.9μm(±S.D),微血管密度是3484.44/mm~2。获得左心室壁心外膜区从微动脉-动脉端毛细血管-毛细血管网-静脉端毛细血管-“萝卜根样”微静脉这个微循环单位的三维空间构型资料。 相似文献
82.
C. Vyvyan Howard Luis M. Cruz-Orive Hiroshi Yaegashi 《Acta neurologica Scandinavica》1992,85(S137):14-19
The recently developed method of total vertical projections is illustrated to estimate the total dendritic length of a human Substantia Nigra neuron. Next, the length of the different orders of dendritic branches, and the mean segment length for each order - commonly regarded as important parameters in neuron physiology - are also estimated. Finally, it is shown how to estimate the mean dendritic length in a population of neurons from vertical slices of arbitrary and unknown thickness. Being unbiased and highly efficient, the proposed methods offer interesting alternatives to current procedures used for the metric analysis of neuron arborizations. 相似文献
83.
Buket Pene Nilgn Atakan Sevin Akkaya Aytac Gkz 《Journal of the European Academy of Dermatology and Venereology》1994,3(4):484-489
In recent years, research on the aetiology of psoriasis has focused on immune aetiopathogenesis. However, in the last few years, research on the immunoloogical changes in psoriasis has failed to mention the lymphatics. Also, studies emphasizing the importance of the dermal lymphatics have neglected the lymphatic changes seen in psoriasis. Therefore, we decided to put this matter back on the agenda. Skin biopsies from 20 patients with psoriasis vulgaris were examined lymphatically by light microscopy using the orcein stain. We found a considerable increase in both number and dilatation in the lymphatics of psoriatic plaques, compared with both the clinically uninvolved skin of the psoriatic patients and also the skin of the control group. 相似文献
84.
本文应用微血管腐蚀铸型扫描电镜,观察了2例3岁幼儿的舌肌和翼内肌的微血管构型。在扫描电镜下,舌肌内的毛细血管网构型分三类:1.花蕊样毛细血管袢;2.云朵样毛细血管网;3.多角形套状毛细血管网。毛细血管铸型的直径为5.3±1.5μm,描述了动脉铸型表面上的内皮细胞核压痕和前毛细血管括约肌压痕的形态特征。讨论了血管袢的结构形态及其机能意义,为理解骨骼肌的微循环的过程提供了形态学基础。 相似文献
85.
NMR microscopy is currently being used as an investigational tool for the evaluation of micromorphometric parameters of trabecular bone as a possible means to assess its strength. Since, typically, the image voxel size is not significantly smaller than individual trabecular elements, partial volume blurring can be a major complication for accurate tissue classification. In this paper, a Bayesian segmentation technique is reported that achieves improved subvoxel tissue classification. Each voxel is subdivided either into eight subvoxels twice the original resolution, or up to four subvoxels along the transaxial direction and the subvoxels optimally classified as either bone or marrow. Based on a statistical model for partial volume blurring, the likelihood for the number of marrow subvoxels in each voxel can be computed on the basis of its measured signal. To resolve the ambiguity of the location of the marrow subvoxels, a Gibbs distribution is introduced to model the interaction between the subvoxels. Neighboring subvoxel pairs with the same tissue label are encouraged, and pairs with distinct labels are penalized. The segmentation is achieved by maximizing the a posteriori probability of the label image using the block ICM (iterative conditional mode) algorithm. The potential of the proposed technique is demonstrated in real and synthetic NMR microscopic images. 相似文献
86.
Summary The blood-brain barrier breaks down following cerebral ischemia, but the exact sequence of events for extravasation of serum proteins and their parenchymal distribution remain uncertain. We studied the distribution of serum albumin in the hippocampus of the gerbil brain using light and electron microscopic immunocytochemical techniques. With light microscopy, there was no reaction for albumin for the first 12 h after unilateral common carotid artery occlusion for 10 min and reperfusion. At 12 h, the reaction was weak and limited to the neuropil in the subiculum-CA1 region (between the subiculum and the medial CA1 region). After 24 h, the reaction became intense in the neuropil and neuronal perikarya in the subiculum-CA1 and medial CA1 regions. The electron microscopic immunocytochemical study of the subiculum-CA1 and medial CA1 regions revealed electron-dense immunoprecipitates in the extracellular space and the peripheral part of the apical dendrites as early as 30 min after reperfusion and in the astrocytic cytoplasm after reperfusion for 1 h. However, immunoprecipitates were not found in the neuronal perikarya until after reperfusion for 24 h. The present study demonstrated prompt appearance of albumin in the extracellular space of the brain parenchyma after re-establishment of cerebral circulation and prompt accumulation in the peripheral part of the dendrites with spreading to neuronal perikarya, likely in the process of degeneration and death.Supported by the grant NS-06663 from the National Institutes of Health, U. S. Public Health Service 相似文献
87.
Early Postnatal Changes in the Somatodendritic Morphology of Ankle Flexor Motoneurons in the Rat 总被引:1,自引:0,他引:1
Joanna Dekkers David L. Becker Jeremy E. Cook Roberto Navarrete 《The European journal of neuroscience》1994,6(1):87-97
The development of locomotor function in the rat spans the first 3 postnatal weeks. We have studied morphological features of the soma and dendrites of motoneurons innervating the physiological flexor muscles of the ankle, tibialis anterior and extensor digitorum longus, by intracellular injection in vitro between the first and ninth postnatal days. We obtained serial optical sections of 96 adequately filled motoneurons in whole-mounted hemisected spinal cords by confocal microscopy, projected them onto a single plane and analysed them morphometrically. On the day after birth, the somatodendritic surfaces of most such motoneurons were covered in growth-associated spiny, thorny or hair-like appendages. These had disappeared from the soma by the fourth postnatal day and from most proximal dendrites by day 7, but were still common distally on day 9. During this period there was little or no net growth of either the soma (which was still much smaller than in the adult) or the dendritic tree. A dorsal dendritic bias was present and 'sprays' of long, loosely bundled dorsal dendrites were often seen. The mean number of primary dendrites remained constant at about eight, and their combined diameter was already significantly correlated with mean soma diameter, as in the adult cat. Thus, the critical neonatal period during which these ankle flexor motoneurons are known to change their electrophysiological properties and to be particularly sensitive to interference with neuromuscular interaction is characterized by major changes in the neuronal surface, presumably linked to synaptogenesis. 相似文献
88.
89.
The effects on endometrial morphology of a single, intramuscular dose of 100 mg of progesterone administered in the early luteal phase, between days LH + 1 and LH + 6, were studied in a group (n = 8) of normal, fertile subjects by morphometric techniques and transmission electron microscopy. While the dose of progesterone administered consistently resulted in an increase of salivary progesterone concentration to above the upper limit of the reference range, no significant effect on endometrial development was observed; in particular, endometrial development was not advanced. 相似文献
90.
Cocaine's enhancement of dopaminergic neurotransmission in the mesolimbic pathway plays a critical role in the initial reinforcing properties of this drug. However, other neurotransmitter systems are also integral to the addiction process. A large body of data indicates that opioids and dopamine together mediate emotional and reinforced behaviors. In support of this, cocaine-mediated increases in activation of dopamine D1 receptors (D1R) results in a desensitization of δ-opioid receptor (DOR) signaling through adenylyl cyclase (AC) in striatal neurons. To further define cellular mechanisms underlying this effect, the subcellular distribution of DOR and D1R was examined in the rat dorsolateral striatum. Dual immunoperoxidase/gold-silver detection combined with electron microscopy was used to identify DOR and D1R immunoreactivities in the same section of tissue. Semi-quantitative analysis revealed that a subset of dendritic cellular profiles exhibited both DOR and D1R immunoreactivities. Of 198 randomly sampled D1R immunoreactive profiles, 43% contained DOR. Similarly of 165 DOR-labeled cellular profiles, 52% contained D1R. The present data provide ultrastructural evidence for co-existence between DOR and D1R in striatal neurons, suggesting a possible mechanism whereby D1R modulation may alter DOR function. 相似文献