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121.
Objective : To measure the functional diameter of alveolar septal microvessels under conditions in which the pulmonary arterial pressure and the lung inflation pressure are equal, at 25 cm H2O (zone I-II border), and to compare these results with those obtained when inflation pressure exceeded arterial pressure by 5 or 10 cm H2O (zone I). Methods : We perfused isolated rat lungs (PA 25, PPA 25, PLA 0 cm H2O) with fluorescent latex particles of specific diameters (0.49, 1.05, 2.0, 4.0, or 10 μm) and then prepared samples for histology. Using a confocal, laser-scanning fluorescence microscope, we measured latex particle densities within the septal plane of individual alveoli. We compared these particle densities with those in arterioles supplying the septa and calculated the density ratio. We fit curves produced by the Verniory equation to these ratios to estimate the septal microvessel functional diameter. Results : Particle densities in septa ranged from 0.06 ± 0.02 particles per μm2 ‘for 0.49-μm-diameter particles to 0.007 ± 0.004 particles per μm2 for 4.0-μm-diameter particles. The 10-μm particles did not enter septa. Calculations based on these data suggest a septal microvessel functional diameter of 6–8 μm. Conclusions : In a previous study, conducted at the same value of Pinflat, but with PPA set at 15 or 20 (5 or 10 cm H2O into zone I), we estimated the capillary diameter to be 1.7 μm. Thus, the septal capillary diameter seems to increase by three- to fourfold as PPA is raised to equal Pinflat. 相似文献
122.
M. Ïmer T. Okar S. Çobanoğlu R. Kayapinar M. Memiş K. Hepgül K. Kutlu 《Acta neurochirurgica》1996,138(10):1246-1249
Summary Modification of a type of end-to-side anastomosis that has been described before is studied. The recipient artery is occluded for only 3–4 minutes to complete the anastomosis by using only the running suture. The anastomotic site was studied by inspection and Scanning Electron Microscope (SEM) at different times after the operation on 30 rats. 相似文献
123.
用辣根过氧化物酶标记的癌胚抗原(CEA)抗体,对结肠腺癌患者的手术标本进行了免疫组织化学染色,观察了CEA在肿瘤组织及正常组织细胞中的分布。结果显示,正常结肠组织中,CEA沿粘膜上皮细胞的游离面分布;结肠腺癌细胞则失去极性,CEA除见于细胞游离面,在细胞侧面和基底面也呈阳性反应。提示CEA在结肠细胞表面的分布失去极性可能是腺癌细胞的特点。 相似文献
124.
YOSHIKAZU YONEI YOSUKE YOSHIZAKI NOBUHIRO TSUKADA YASUTAKA INAGAKI KEI MIYAMOTO OSAMU SUZUKI YASUYOSHI KIRYU TOSHIFUMI HIBI MASAYA ODA HIROMASA ISHII 《Journal of gastroenterology and hepatology》1996,11(7):681-685
An ultrastructural study of the colonic mucosa was performed in four patients with antibiotic-associated haemorrhagic colitis and new findings are reported. Colonoscopy was performed and biopsy specimens were obtained within 24 h of the onset of bloody diarrhoea. Colonoscopy demonstrated diffuse oedematous and haemorrhagic mucosa with erosions and white coat. Light microscopy revealed mucosal haemorrhage and inflammatory cell infiltration. Ultrastructurally, platelet aggregation was frequently present in the lumina of colonic mucosal capillaries, causing engorgement of red blood cells in adjacent microvessels. Mild to severe damage was observed in capillary endothelial cells, including discontinuity of basement membranes, gaps between endothelial cells and the destruction of capillaries. There was no evidence of microvascular spasm. In conclusion, our findings suggest that antibiotics directly or indirectly cause microcirculatory disturbances, which result in tissue damage and haemorrhage, in the colonic mucosa. 相似文献
125.
A. D. Katsen B. Vollmar P. Mestres-Ventura M. D. Menger 《Virchows Archiv : an international journal of pathology》1998,433(1):75-83
Tumour necrosis factor (TNF)-α-induced apoptosis is associated with several nuclear and cell surface alterations, in particular
with the condensation of chromatin and the fragmentation of the cell nucleus, formation of blebs on the cell surface and breakdown
of the plasma membrane. However, there is little information about the relationship between the cell surface alterations and
the nuclear changes during apoptosis. To study this, cultured WEHI cells were exposed to TNF-α over different time periods.
The cytological changes were studied using a correlative approach, which allowed observation of the same cell consecutively
under light, scanning and transmission electron microscopy. The earliest sign of cell alteration was a reduction of the number
of microvilli after 15 min of TNF-α exposure. This reaction was reversible (reappearance of microvilli) and took place during
the first hour, in which neither nuclear alterations nor plasma membrane breakdown were observed. The changes in the nucleus
began with condensation of chromatin after approximately 1 h of TNF-α-exposure. After 4–5 h the microvilli disappeared again,
particularly in areas where the formation of blebs (blebbing) was observed. Strikingly, cell surface alterations (bleb formation)
were detected only in those cells that presented with condensed chromatin, and not in cells with a normal chromatin pattern,
proving at least a close correlation between nuclear and cell surface changes during the process of apoptosis.
Received: 7 October 1997 / Accepted: 23 March 1998 相似文献
126.
应用扫描电镜观察9位育龄期妇女正常和结扎后的输卵管上皮。结果表明:在输卵管结扎疤痕两侧各0.5cm处,粘膜上皮细胞的纤毛大量扭曲和粘连,局部上皮纤毛和微绒毛脱落,细胞形态不规则,而在距输卵管结扎疤痕两侧各1.0cm处,上皮细胞的纤毛和微绒毛形态和结构均正常。表明输卵管结扎后上皮的超微结构变化,使卵细胞输送功能丧失,可能是输卵管复通术后不孕的重要原因。因此,施行输卵管复通术时,输卵管疤痕切除的范围应不少于疤痕两侧各0.5cm,以提高输卵管复通率。此外,发现输卵管小孔仅位于输卵管积水处粘膜的分泌细胞间,可能与输卵管浆膜下毛细淋巴管相沟通,与引流输卵管积水有关。在输卵管积水处粘膜的表面纤毛细胞的纤毛大量脱落,微绒毛增生,许多纤毛细胞转变为分泌细胞。提出了形成输卵管积水新的发病机理。 相似文献
127.
Summary We report two cases of Creutzfeld-Jakob disease with clusters of giant collagen fibers. To our knowledge, these abnormally large collagen fibers have never been described in patients with degenerative diseases of the central nervous system. The significance of the formation of such plaque-like large collagen fibers has as yet not been elucidated. It is felt that these represent a product of the degenerative process.Presented in part at the 68th Annual Meeting of the American Association of Neuropathologists, St. Louis, Missouri, June 18–21, 1992 相似文献
128.
Adult-onset rod disease with abundant intranuclear rods 总被引:2,自引:0,他引:2
Summary The third case of adult-onset rod disease (nemaline myopathy) with abundant myofibrillar as well as intranuclear rods is described. The 61-year-old woman suffered from progressive weakness of proximal extremities and of the neck, mimicking polymyositis. Muscle biopsy revealed a striking myopathic pattern, with intranuclear rods occurring in 31% of the fibres. On light and electron microscopy and by immunohistochemical study, the rods differed from myofibrillar rods. The absence of -actinin in intranuclear rods suggests an enhanced readiness of actin filaments to bind to diverse proteins, instead of overproduction of -actinin as the pathogenetic basis of the rod formation. 相似文献
129.
家兔输卵管结扎术后黄体的形态变化 总被引:2,自引:0,他引:2
将27只雌性家兔随机分为五组,即Pomeroy法扎管组;Uchida法扎管组;结扎子宫动脉组;结扎卵巢动脉组和假手术组。术后4~10周合笼交配。交配后第八天取黄体做光镜和透射电镜观察。结果:Uchida法扎管后黄体的形态正常;Pomeroy法扎管和结扎子宫动脉后黄体的形态有轻微改变;结扎卵巢动脉后黄体的形态有明显改变。研究结果对探讨“扎管后综合征”的发生机制具有一定的意义。 相似文献
130.
Time-dependent morphological alterations of cold-stored small bowel in Euro-Collins and Ringer's lactate solutions 总被引:2,自引:0,他引:2
Small bowel is one of the organs that can in principle be transplanted. Optimum preservation of the organ is essential for the success of transplantation. The aim of the present study is the investigation of time-related morphological changes of rat small bowel during preservation in hypothermic Euro-Collins (EC) and Ringer's lactate (RL) solution using light microscopy and transmission electron microscopy to evaluate the integrity of intercellular complexes of mucosal epithelium, one of the tissues of the intestine that is most susceptible to ischemia. Small bowels were perfused with either EC, RL solution or physiological saline solution and were placed in the different preservation solutions at 4 degrees C for 0, 3, 6 and 12 h. The results of our study suggest that both preservation solutions are suitable for short-term preservation of the small bowel although RL solution is more effective than EC solution. However, we conclude that further improvement of preservation solutions and/or techniques are needed to perform long-term preservation. 相似文献