The high degree of ultrastructural organization of microtubular crystals (1, 2) produced in mammalian cells by incubation with Vinca alkaloids, suggested that these crystals would be birefringent in polarized light. We now report the induction by vinblastine sulfate (VBL) of birefringent crystals in unfertilized oocytes of the starfish Pisaster ochraceous . Mature ovaries were removed, placed i...

Zona-free oocytes of the mouse were inseminated at prometaphase I or metaphase I of meiotic maturation in vitro, and the behavior of the sperm nuclei within the oocyte cytoplasm was examined. If the oocytes were penetrated by up to three sperm, maturation continued during subsequent incubation and became arrested at metaphase II. Meanwhile, each sperm nucleus underwent the following changes. Fi...

The transition from metaphase to anaphase is regulated by a checkpoint system that prevents chromosome segregation in anaphase until all the chromosomes have aligned at the metaphase plate. We provide evidence indicating that a kinetochore phosphoepitope plays a role in this checkpoint pathway. The 3F3/2 monoclonal antibody recognizes a kinetochore phosphoepitope in mammalian cells that is expr...

A technique has been developed to examine the same G-banded human metaphase chromosomes, first in the light microscope and then in the scanning electron microscope (SEM). A structural involvement in chromosome banding was confirmed by a positional correlation between the G-positive bands observed in the light microscope and the circumferential grooves between the quaternary coils of the metapha...

PURPOSE OF REVIEW To evaluate current and previous findings related to a timely implementation of in-vitro maturation (IVM) of germinal vesicle, metaphase I and metaphase II oocytes with an optimal cryopreservation to determine whether IVM should be attempted prior to (fresh IVM) or IVM after cryopreservation (postthaw IVM). Mitochondrion, chromatin and spindle formation in both groups were int...

Duplicated mitotic chromosomes aligned at the metaphase plate maintain dynamic attachments to spindle microtubules via their kinetochores, and multiple motor and nonmotor proteins cooperate to regulate their behavior. Depending on the system, sister chromatids may display either of two distinct behaviors, namely (1) the presence or (2) the absence of oscillations about the metaphase plate. Sign...

In this paper we report our experiences with a new texture coarseness measure, as a step towards automation of metaphase finding in cell proliferation studies. This measure is highly specific to grey-level inter-chromosome coarseness features in microscopic images of metaphase spreads, and allows to quantify the texture of the cytological objects analysing the intensity profile between chromoso...