title: A novel technique for observing the internal ultrastructure of human chromosomes with known karyotype.
abstract: Observation of the internal ultrastructure of human chromosomes by transmission electron microscopy (TEM) has frequently been attempted in spite of the difficulties in detaching metaphase chromosome spreads from the glass slide for further processing. In this study we have used a method in which metaphase chromosome spreads were prepared on a flexible thermoplastic membrane (ACLAR) film. To assess chromosome identity, a diamidino-phenylindole staining and karyotying was first done using a conventional cytogenetic system. The chromosome spreads were then fixed with 1% osmium tetroxide, stained with freshly prepared 2% tannic acid, dehydrated, and flat-embedded in epoxy resin. The resin sheet was easily detachable and carried whole chromosome spreads. By this method, TEM observation of chromosomes from normal human lymphocytes allowed a thorough examination of the ultrastructure of centromeres, telomeres, fragile sites, and other chromosomal regions. Various ultrastructural patterns including thick electron dense boundaries, less dense internal regions, and extended chromatin loops at the periphery of the chromosomes were discernible. Application of the present method to chromosome research is expected to provide comprehensive information on the internal ultrastructure of different chromosomal regions in relation to function.
authors.affiliation: Department of Molecular Pathology, Institute of Gerontology, Nippon Medical School, Kawasaki, Japan. ciem@nms.ac.jp
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghazizadeh
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Oguro
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sato
authors.forename: Seiko
authors.initials: S
authors.lastname: Egawa
authors.forename: Kyoko
authors.initials: K
authors.lastname: Inoue
authors.forename: Akiko
authors.initials: A
authors.lastname: Adachi
authors.forename: Hajime
authors.initials: H
authors.lastname: Shimizu
authors.forename: Oichi
authors.initials: O
authors.lastname: Kawanami
mesh_terms: D002503:Centromere / Q000648:ultrastructure; D002877:Chromosomes, Human / Q000648:ultrastructure*; D006801:Humans; D007621:Karyotyping; D008214:Lymphocytes / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D013194:Staining and Labeling; D016615:Telomere / Q000648:ultrastructure