leiomyoma is a very rare intraocular tumor, which can occur in the iris, ciliary body and choroids. we report a case of choroidal leiomyoma in a 16-years old women whose left eye was enucleated because of clinical suspicion for melanoma. using conventional light microscopy tumor was interpreted as spindle cell tumor, most probably of neurogenic origin and after using immunohistochemical studies...

BACKGROUND Cellular structures such as the nucleus, Golgi, centrioles, and spindle show remarkable diversity between species, but the mechanisms that produce these variations in cell biology are not known. RESULTS Here we investigate the mechanisms that contribute to variations in morphology and dynamics of the mitotic spindle, which orchestrates chromosome segregation in all Eukaryotes and p...

Precise regulation of stem cell self-renewal/differentiation is essential for embryogenesis and tumor suppression. Drosophila neural progenitors (neuroblasts) align their spindle along an apical/basal polarity axis to generate a self-renewed apical neuroblast and a differentiating basal cell. Here, we genetically disrupt spindle orientation without altering cell polarity to test the role of spi...

Spindle cell lipoma is a benign lipomatous tumour that mainly occurs in the subcutis of the head, neck, and shoulder in elderly men. Oral spindle cell lipoma is extremely rare in all species, and no cases have been reported in veterinary medicine. A 10-year-old male Maltese dog was presented for evaluation of a whiteto cream-coloured gingival mass. Microscopically, the mass was composed of matu...

At the end of the cell cycle a cell physically divides into two daughter cells in a process called cytokinesis. Cytokinesis consists of at least four steps: (1) The position of the presumptive cytokinesis furrow is specified. (2) A contractile ring is formed. (3) The contractile ring contracts, resulting in furrow ingression. (4) Cytokinesis completes with sealing of the membranes. The mitotic ...

During cell division, the molecular motor Eg5 crosslinks overlapping antiparallel microtubules and pushes them apart to separate mitotic spindle poles. Dynein has been proposed as a direct antagonist of Eg5 at the spindle equator, pulling on antiparallel microtubules and favoring spindle collapse. Some of the experiments supporting this hypothesis relied on endpoint quantifications of spindle p...

For several years the authors have been interested in certain peculiar tumors of the skin and mucous membranes which have been designated as spindle-cell epidermoid carcinomas. Most of these lesions have occurred in the zone including and surrounding the lip, and this particular group has been especially selected for the present study, although tumors of somewhat similar histology have been not...

Asymmetric cell division is essential to generate cellular diversity. In many animal cells, the cleavage plane lies perpendicular to the mitotic spindle, and it is the spindle positioning that dictates the size of the daughter cells. Although some properties of spindle positioning are conserved between distantly related model species and different cell types, little is known of the evolutionary...

Adducin-1 moonlights at the mitotic spindle A n actin-binding protein helps shape the mitotic spindle, Chan et al. report. Researchers long thought that actin and microtubules performed different tasks during mitosis. They believed that micro tubules formed the mitotic spindle that pulls chromosomes apart, whereas actin joined with myosin to produce the contractile furrow that separates the mot...

Size specification of macromolecular assemblies in the cytoplasm is poorly understood [1]. In principle, assemblies could scale with cell size or use intrinsic mechanisms. For the mitotic spindle, scaling with cell size is expected, because the function of this assembly is to physically move sister chromatids into the center of nascent daughter cells. Eggs of Xenopus laevis are among the larges...