Presence of matrix vesicles in the body of odontoblasts and in the inner third of dentinal tissue: a scanning electron microscopic study.
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OBJECTIVES: The aim of this report is to present the results of a scanning electron microscopic study on the presence of matrix vesicles (MVs) found in human dentine. STUDY DESIGN: Dentin tissue from 20 human bicuspids was analyzed by means of scanning electron microscopy. RESULTS: MVs were found as outgrowths of the cellular membrane of the odontoblastic body, the more proximal portion of the odontoblastic process before entering the dentinal tubule and in the odontoblastic process within the inner third of the dentin. Size of MVs varied depending on location. In the inner third of dentin, they were seen in diverse positions; as membranal outgrowths, deriving from the odontoblastic process, lying free in the intratubular space and attached to the dentinal wall. Sometimes, they were seen organized forming groups of different sizes and shapes or as multivesicular chains running from the surface of the odontoblastic process to the tubular wall. MVs were present in places never considered: 1) the body of odontoblasts; 2) the most proximal part of the odontoblastic processes before entering the circumpulpal dentine and also: 3) in the inner third of dentinal tissue. CONCLUSIONS: According to our results, MVs not only participate during mantle dentin mineralization during early dentinogenesis, they also contribute during the mineralization process of the inner dentin. (+info)
Oxidative responses induced by pharmacologic vitreolysis and/or long-term hyperoxia treatment in rat lenses.
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Mutation detection of type II hair cortex keratin gene KRT86 in a Chinese Han family with congenital monilethrix.
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BACKGROUND: Monilethrix is an autosomal dominant hair disorder characterized clinically by alopecia and follicular papules. In this study, we collected a Han monilethrix family to detect the mutations in patients and investigated the correlation between the genotype and phenotype of monilethrix. METHODS: In this study, we identified a Chinese family with monilethrix through light microscopic and scanning electron microscopic (SEM) examination. Genomic DNA from peripheral blood samples was prepared. DNA samples from controls and monilethrix patients were subject to polymerase chain reaction (PCR) amplification. Two pairs of primers were used to amplify the seventh exon of KRT86. Mutation screening of the PCR products was detected using direct sequencing. RESULTS: Light microscopic examination showed a regular alternate enlargement and narrow area. SEM examination showed that part of the cuticle of the nodules shed and disappeared gradually in the narrow area with granular protrusions on the surface similar to the erosion-like structure. Parallel longitudinal ridge and groovepattern appeared, and the ridges varied in width, like dead wood. A heterozygous transversion mutation c.1204G > A (p.E402K) in the seventh exon of KRT86 was identified in both patients. CONCLUSIONS: The mutation of extron 7 of KRT86 identified plays a major role in the pathogenesis of this pedigree with monilethrix, and is a mutation hot spot of KRT86. Further research is needed to explore the relationship between the phenotype and the mutation of the type II hair keratin gene KRT86 of monilethrix. (+info)
Ion permeability of the nuclear pore complex and ion-induced macromolecular permeation as studied by scanning electrochemical and fluorescence microscopy.
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