原子力显微镜及其在生物医药学研究中的应用

本文介绍了原子力显微镜的工作原理及特点,并对其三种工作模式进行了比较,重点介绍了更适用于生物医药研究的敲击式工作模式以及原子力显微镜在生物医药学研究中的应用.     

家兔阑尾淋巴管铸型的扫描电镜研究

用淋巴管铸型、冰冻断裂样品及半薄切片样品观察了家兔阑尾巴管及泡周围淋巴窦的立体构筑，可见在阑尾粘膜浅层存在一层毛细淋巴管网，粘膜深层有致密的毛细淋巴管丛，从毛细淋巴管丛发出许多短树枝样毛细淋巴管伸向胸腺依赖区。从粘膜浅层毛细淋忱网及粘膜深层毛细淋巴管丛都发出与腔面垂直的毛细淋巴管，与滤泡周围淋巴窦相连，滤泡周围淋巴窦位于淋巴滤泡的外面和底面从腔面观察，滤泡财要巴窦与粘膜深层的毛细淋巴管丛共同形成茶     

感染高原属兔的皮蝇蛆Ⅲ期幼虫的电镜形态学比较研究

为了观察感染高原鼠兔与感染牦牛、藏羚羊的皮蝇蛆Ⅲ期幼虫之间形态学上的区别,在青海省玉树县和称多县收集感染高原鼠兔的皮蝇蛆与本研究室以往收集保存的感染牦牛、藏羚羊皮蝇蛆进行比较研究。取出蝇蛆晾干酒精,用戊二醛液固定,切下幼虫的头部和尾部用锇酸溶液固定,不同浓度的酒精脱水、临界点干燥、表面喷金后,扫描电镜观察。感染鼠兔的皮蝇蛆伪头部口裂背侧没有明显的肉质突起,腹面棘成连续的1簇,伪头突起与口裂之间有许多细密的小棘,气门板稍凸起,圆形,上面无棘;第10节腹面前缘棘大,圆形,后缘棘小,散在。与感染牦牛的牛皮蝇蛆、纹皮蝇蛆、中华皮蝇蛆及感染藏羚羊的皮蝇蛆在形态上有明显的区别。     

Scanning electron microscopic study of the human auditory ossicles

The human mallei, incudes and stapedes from 34 cadavers were examined using scanning electron microscope (SEM) to compare the bone surface type among different regions of auditory ossicles for males and females. On the malleus of both males and females, almost all of the surfaces showed a smooth fibrous appearance, characteristic of resting surface. Limited bone-forming or resorbing surfaces were identified on the malleus. As compared with the malleus, the percentage area of the resorbing surface and the vascular canal openings were higher on the incus and stapes, especially on the long process (Crus longum) of the incus and the neck of the stapes for both males and females. The percentage area occupied by the resorbing surface of the long process of the incus and the neck of the stapes correlated with that of the vascular canal openings. We consider that the malleus maintained the stable condition, while the long process of the incus and the neck of the stapes demonstrated marked bone resorption. We suppose that the bone erosion may be related to the vascularization in these regions. Though the percentage area of the resorbing surface and the vascular canal openings had the tendency to be high in females, we did not find any significant differences between the males and females. There was no significant correlation between the age and the area of resorbing surface or vascular canal openings.     

Endophytic population of Pantoea agglomerans in citrus plants and development of a cloning vector for endophytes

Harmless bacteria inhabiting inner plant tissues are termed endophytes. Population fluctuations in the endophytic bacterium Pantoea agglomerans associated with two species of field cultured citrus plants were monitored over a two-year period. The results demonstrated that populations of P. agglomerans fluctuated in Citrus reticulata but not C. sinensis. A cryptic plasmid pPA3.0 (2.9 kb) was identified in 35 out of 44 endophytic isolates of P. agglomerans and was subsequently sequenced. The origins of replication were identified and nine out of 18 open reading frames (ORFs) revealed homology with described proteins. Notably, two ORFs were related to cellular transport systems and plasmid maintenance. Plasmid pPA3.0 was cloned and the gfp gene inserted to generate the pPAGFP vector. The vector was introduced into P. agglomerans isolates and revealed stability was dependent on the isolate genotype, ninety-percent stability values were reached after 60 hours of bacterial cultivation in most evaluated isolates. In order to definitively establish P. agglomerans as an endophyte, the non-transformed bacterium was reintroduced into in vitro cultivated seedlings and the density of inner tissue colonization in inoculated plants was estimated by bacterium re-isolation, while the tissue niches preferred by the bacterium were investigated by scanning electronic microscopy (SEM). Cells from P. agglomerans (strain ARB18) at similar densities were re-isolated from roots, stems and leaves and colonization of parenchyma and xylem tissues were observed. Data suggested that P. agglomerans is a ubiquitous citrus endophyte harboring cryptic plasmids. These characteristics suggest the potential to use the bacterium as a vehicle to introduce new genes in host plants via endophytic bacterial transformation.     

Scanning and transmission electron microscopic study of visceral and parietal peritoneal regions in the rat

The visceral peritoneum of intraabdominal organs (spleen, stomach, liver, small intestine), omentum majus and the parietal peritoneum of the anterior abdominal wall and the diaphragm were studied in adult Wistar rats by combined scanning and transmission electron microscopy (SEM, TEM). In general, the peritoneal surface consisted of a mesothelium composed of cubic, flat or intermediate cell types delimited by a basal lamina. Cubic mesothelial cells predominated in parenchymal organs (spleen, liver) and were characterized by prominent and indentated nuclei, a cytoplasm richly supplied with organelles, a dense microvillous coat, basal invaginations and elaborate intercellular contacts. Flat mesothelial cells were observed in the intestinal, omental and parietal peritoneum (tendinous diaphragm, abdominal wall) and showed elongated nuclei, scant cytoplasm, a poorly developed organelle apparatus and sparsely distributed microvilli. An intermediate mesothelial cell type was described within the gastric peritoneum characterized by a central cytoplasmic protrusion at the nuclear region containing most of the cytoplasmic organelles and by thin finger-like cytoplasmic processes. The submesothelial connective tissue layer was composed of collagen fiber bundles, fibroblasts and free cells (macrophages, granulocytes, mast cells) and contained blood and lymphatic vessels. In the spleen, elastic fibers formed a membranous structure with intercalated smooth muscle cells. Mesothelial openings were observed as tunnel-like invaginations within the hepatic peritoneum and as clusters of peritoneal stomata within the parietal peritoneum of the anterior abdominal wall and the muscular diaphragm. The round or oval openings of the peritoneal stomata were frequently occluded by overlapping adjacent mesothelial cells and their microvillous coat or obstructed by cellular material. At the side of the peritoneal stomata the mesothelial cell layer was interrupted to allow a direct access to the underlying submesothelial lymphatic system. The mesothelium and lymphatic endothelium shared a common basal lamina. The endothelial cells were discontinuous and displayed valve-like plasmalemmatic interdigitations facilitating an intercellular transport of fluids and corpuscular elements from the peritoneal cavity to the submesothelial lymphatic lacunae. The findings underline the morphological heterogeneity of the peritoneum in visceral and parietal regions, suggesting different functional implications, and further support the presence of extra-diaphragmatic peritoneal stomata.     

大鼠颈动脉显微和超微结构的增龄变化

目的:观察不同年龄组大鼠颈动脉显微及其超微结构,探讨大鼠颈动脉内皮细胞在动脉老化发生发展过程中的变化特点.方法:30只大鼠按其月龄分为青年组(2～3月龄)、成年组(10月龄)和老年组(28～30月龄),每组10只.大鼠颈动脉固定、切片后,每只大鼠随机选切片5张,每张切片随机取4个视野,分别在光学显微镜、扫描电镜、透射电镜下,观察并比较各组大鼠颈动脉结构特点.结果:青年组大鼠颈动脉厚薄较均匀,管腔内表面光滑,内膜、中膜和外膜分界清楚,内皮细胞胞浆丰富均匀,核膜完整,表面有微绒毛;成年组大鼠颈动脉厚薄欠均匀,部分内皮细胞增厚,内皮细胞完整,胞浆稀薄,细胞器减少;老年组大鼠颈动脉厚薄不均一性,管腔内表面欠光滑,内膜可见明显隆起增厚,内皮层脱落、肿胀、增生或缺失,内皮细胞胞浆稀薄,细胞浆较少,微绒毛消失.结论:与青年组、成年组大鼠相比,老年组大鼠颈动脉内膜结构破坏严重,各层结构欠清晰,内皮细胞表面微绒毛消失,出现脱落衰老凋亡现象,并有红细胞等附着.     

绝经后骨质疏松症患者血清NO-iNOS系统及相关激素水平变化的探讨

观察绝经后骨质疏松症(PMO)患者NO、诱导型一氧化氮合酶(iNOS)及E2、GH、PTH、25(OH)D3等相关激素,探讨NO-iNOS系统及相关激素在骨质疏松发病机制中的作用和意义.80例绝经1年以上女性,根据扫描骨密度(BMD),Tscore值,分为骨质疏松组(OP组)34例,非骨质疏松组(NOP组)46例,及绝...     

基于腹腔镜手术训练的眼动特征研究

在腹腔镜模拟训练过程中,研究不同训练模式下被测试者的注视策略,探索腹腔镜训练的新模式。被测试者被随机分为无指导组,视频学习组和专家指导组进行左右移环任务。利用Tobii X1 Light型眼动仪调用模拟训练箱中的摄像头,采集受试者的眼动数据。通过对数据处理分析,计算注视点个数,平均注视时间,注视时间百分比,扫描距离指标。与对照组相比,视频学习和专家指导模式下,任务完成时间降低23%,扫描距离缩短25%,注视点个数减少17%,平均注视时间没有显著差异。视频组和专家指导组之间无明显差异。结果表明不同学习模式下,被测试者的注视行为有明显差异。视频学习和专家指导下效果更好,可以用专家操作时的注视点视频指导初级训练者进行训练。     

Occlusion and subsequent re-canalization in early duodenal development of human embryos: integrated organogenesis and histogenesis through a possible epithelial-mesenchymal interaction

Histogenesis of the duodenum, especially changes in the epithelium in relation to temporal occlusion and re-canalization of the lumen, was investigated by light microscopy together with morphometric analysis, as well as by scanning and transmission electron microscopy of 133 externally normal human embryos ranging from Carnegie stage 12 to 23. A series of morphogenetic events passed the duodenum in a cranio-caudal (proximo-distal) wave like fashion during the period examined. They included: (1) a decrease in the caliber and area of the lumen, (2) ’occlusion’ of the lumen, (3) vacuole formation, (4) ’re-canalization’ and villi formation. The only exemption to this rule was that, in the upper part of the duodenum, the lumen was not obliterated in the embryos examined. Morphometric analyses revealed that both the area of the epithelium and the number of epithelial cells decreased during the ’occlusion’ phase. This result suggests that, unlike the classical view, epithelial cell proliferation does not play an important role in occluding the lumen, but the predominant morphogenetic event during this phase is convergence of the epithelial cells to elongate the duodenum. Apoptosis, contrary to some classical views, decreased during the ’re-canalization’ phase, and it appeared to be involved in the formation of the small lumens in the epithelial ’plug’ and in villi formation, but not in enlarging the secondary lumens. The secondary small lumens in the occluded lumen were frequently formed near the border between the central ’plug’ and peripheral basal cells on the basement membrane. This and other findings of concentric differentiation in both the epithelial and mesenchymal layers suggested a possible control mechanism by the epithelium-mesenchymal interaction on human duodenal morphogenesis and histogenesis. The present electron microscopic observations also provided details on the mechanisms involved in the enlargement of the secondary lumen and differentiation of villi. The implications of these findings to duodenal anomalies are also discussed. Accepted: 12 November 2001