Search results for "Meiosis II"
showing 3 items of 3 documents
The oxidizing agent tertiary butyl hydroperoxide induces disturbances in spindle organization, c-meiosis, and aneuploidy in mouse oocytes
1996
It has been recently proposed that a concomitant generation of oxidative stress of oocytes with increasing maternal age may be a major factor responsible for the age-related increase in aneuploid conceptions. As a preliminary step in the testing of this hypothesis, we need to confirm that oxidative stress in itself can induce errors in chromosome segregation. In order to achieve this goal, germinal vesicle (GV)-stage mouse oocytes from unstimulated ICR and (C57BL x CBA) F1 hybrid female mice were matured in vitro for 9 h for metaphase I (MI) oocytes or 16 h for metaphase II (MII) oocytes in the presence of varying concentrations of the oxidizing agent tertiary-butyl hydroperoxide (tBH). MII…
Skeletal abnormalities of the upper limbs--neonatal diagnosis of 49,XXXXY syndrome.
2012
A case of neonatal diagnosis of 49,XXXXY syndrome is presented. Clinical identification was prompted by a bilateral thickening of the radioulnar joints and X-ray imaging disclosing almost complete radioulnar synostosis. Conventional karyotyping was initiated and revealed a karyotype of 49,XXXXY. Previously reported neonatal symptoms such as low birth weight, muscular hypotonia, or genital malformations were absent in this case. Microsatellite analysis showed two different X chromosomes each present in two copies, supporting that the four X chromosomes had arisen from a nondisjunction in maternal meiosis I followed by a second nondisjunction involving both X chromosomes in meiosis II. Multid…
Distribution of gamma‐tubulin differs in primary and secondary oocytes of Ephestia kuehniella (Pyralidae, Lepidoptera)
1996
In a previous study, barrel-shaped spindles were found in metaphase I oocytes of Ephestia kuehniella (Pyralidae, Lepidoptera). Aster microtubules (MTs) were missing (Wolf, 1993 : Cell Motil Cytoskeleton 24 :200-204). This points to an acentriolar organization of the spindle apparatus. The present study was aimed at the question of whether gamma-tubulin, a newly detected member of the tubulin superfamily that has often been identified in microtubule-organizing centers, plays a role in the nucleation of MTs in meiotic spindles of the moth. To this end, the distribution of gamma-tubulin was examined in oocytes of E. kuehniella using an antibody against gamma-tubulin in combination with indirec…