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Biomedical subjects

T Ikeuchi

Publications and source records attributed to T Ikeuchi.

284 records · Page 16Linked to original sources

Induction of nuclear envelopes around metaphase chromosomes after fusion with interphase cells.

The process of cellular fusion induced by Sendai virus in Chinese hamster cells (Don line) afforded us the opportunity to study nuclear envelope formation around metaphase sets in the presence of interphase nuclei, when chromosome pulverization failed to occur in such multinucleate cells. Morphologically, the enveloped metaphase chromosomes resembled a normal telophase nucleus, though minor differences prompted us to call it telophase-like. Electron microscopic observations demonstrated that the membranes enveloping the chromosomes appeared to be identical with a normal nuclear envelope. The longer the cells were incubated with Colcemid before fusion, the higher was the number of cells with telophase-like nuclei and the lower the percentage of cells with pulverizations. Furthermore, the number of pulverizations bore a somewhat direct relationship to the ratio of metaphase to interphase nuclei in multinucleate cells, and the number of telophase-like nuclei was inversely proportional to this ratio. A hypothesis is advanced in which a balance between the activities of a chromosome pulverization factor and a nuclear envelope formation factor, the former in metaphase cells and the latter in interphase cells, is decisive as to the nature of morphologic events observed in virus-induced fused cells.

Animals↗

A 14-year-old patient with Ewing's sarcoma presenting at autopsy with multiple neurofibrillary tangles and Lewy bodies in addition to hemiatrophy of the central nervous system.

The autopsy findings of a 14-year-old Japanese girl with Ewing's sarcoma, who had multiple neurofibrillary tangles and Lewy bodies and hemiatrophy of the central nervous system (CNS), are reported. She had retinoblastoma of her right eye 8 months after birth, which was treated with chemotherapy and irradiation (40 Gy), twice, seizures 1 year and 2 months after birth, and thereafter severe mental retardation. She showed left hemiparesis after a febrile seizure at the age of 7 years and CT disclosed the right cerebral hemiatrophy. For the last 2 years of life she suffered from Ewing's sarcoma. Extrapyramidal signs were absent. Neuropathologically, tangles consisting of paired helical filaments were distributed symmetrically in virtually all the grey matter. They were particularly numerous in the frontal cortex and substantia nigra, but sparse in the nucleus of Meynert, hippocampus, and brainstem. Several Lewy bodies, which were ultrastructurally identical to those seen in Parkinson's disease, were present in the substantia nigra (more on the left than right) and locus coeruleus. Morphometrically, the number and size of substantia nigral neurons were reduced, the reduction in the latter being more marked than the former, but the melanin pigment contents and shapes of the remaining neurons appeared normal. The right cerebral hemiatrophy with contralateral cerebellar hemiatrophy may have been attributable to irradiation. Although our patient did not have parkinsonism, her features resembled those of a 28-year-old autopsy case reported by Popovich et al. [1987].

Adolescent↗