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Objective To reveal the fibrillar network in vitreous and the effect of plasmin on this network. Methods 20 vitreous gels of freshly slaughtered pigs were divided into 2 groups, the gels in first group were digested by 3 U plasmin (3 U/ml) at 37℃ for 24 hours respectively, the second group received the same PBS as control. After digestion, gels were fixed in neutral buffered formalin solution. Samples from vitreous base, cortex and the central region were observed by the technique of freeze etching electron microscopy. Results In vitreous collagen fibril network was in a three-dimensional array, collagen fibril density showed marked differences, central vitreous had the sparse fibril density, the cortex denser and the basal vitreous densest. After digestion by plasmin, the collagen fibrillar network was destructed. Conclusion Collagen fibrils in vitreous present spatial arrangement regularly, plasmin can lead to destruction of the fibrillar network.
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By transmission electron microscopy and freeze etching technique 15 human fetuses were utilized to study the ultrastructure of the mesothelial cells on the parietal peritoneum. The mesothelial cells of the diaphragmatic peritoneum contained numerous vesicles which were frequently communicated with the free surface, the basement membrane, intercellular space and the peritoneal stomata. Some of the vesicles seemed to fuse each other and form vacuoles. Vacuoles also occurred close to, or communicated with the basement membrane and cell free surface. Sometimes they appeared as secretory particles. The microvilli contained vesicles opened to the free surface. The mesothelial cells on the pelvic wall displayed abundant endoplasmic reticulum and Golgi apparatus, but scanty vesicles. So, the mesothelial cells on parietal peritoneum of human fetuses might be classified into two types, i. e. the vesiclecontaining cells on the diaphragmatic peritoneum and the ER-containing cells on the peritoneum of the pelvic wall. The vesicle-containing cells seemed to uptake material from the peritoneal cavity. Abundant endoplasmic reticulum and Golgi apparatus reflected a high synthetic activity, hence the ER-containing cells might be possibly related to the production of peritoneal fluid.
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The fine ultrastructure and localization of acid phosphatase in cell ultrastructuralevel of a HGPRT-human promyelocytic leukemia cell mutant(HL-60-AR)arestudied by scanning electron microscopy,transmission electron microscopy,freezeetching,and electron microscopic cytochemistry techniques.The results of theobservation show that the ultrastructural characteristics of HL-60-AR cells aresimilar to that of HL-60 cells.There are microvilli and ridges over cell surface.Thecells have large nucleus with prominent nucleoli,and numerous nuclear pores.Thereare less developed Golgi complex,expanded rough endoplasmic reticulum andabundant polyribosomes.After treatment with retinoic acid(RA)at 10~(-6) mol/L for 5days,HL-60-AR cells differentiate along myeloid pathway and have a decreasednucleocytoplasmic ratio accompanied with nuclear condensation and segmention.A (?)ignificant increase of specific granules is demonstrated.Microvilli of the cellsdisappear,surface features of the treated cells become more irregular and largeprotrusion and blunt pseudopodia appear.Increase of acid phosphatase content localizedon azurophilic granules(lysosomes)and Golgi complex is showed.The application offour kinds of electron microscopic techniques might provide the best way foridentifying cell ultrastructure.