Search results for "mitos"
showing 10 items of 190 documents
Desmoplastic primitive nonneural granular cell tumor of the skin.
2014
Abstract Primitive nonneural granular cell tumor of the skin was first described by LeBoit et al in 1991 as "primitive polypoid granular cell tumor." Few cases have been reported to date, all being polypoid or deep well-delimited lesions and formed by large spindle or polygonal granular cells with moderate nuclear atypia and increased mitotic activity. This granular cell population does not have a Schwannian, myogenic, melanocytic, fibroblastic, histiocytic, or epithelial differentiation. We report a case that fully satisfies the criteria for primitive nonneural granular cell tumor of the skin and, in addition, shows an extensive desmoplastic stroma. This desmoplastic variant of primitive n…
Correlations of female steroid hormone receptors with histologic features in meningiomas.
1991
A series of 39 samples were obtained from meningiomas in 28 patients in order to investigate the relationships of the oestrogen receptor (OER) and progesterone receptor (PR) with the tumoural subtype and some histological features. Twenty-one samples were positive (greater than 10 fmole/mg protein), 7 were OER-PR-negative, and 1 was positive in both receptors. Twenty-two samples were considered as syncitial, 7 transitional, 7 fibroblastic and 3 angioblastic. The histological subtype was not found to be significantly related to the presence or absence of PR. Relations were not observed between the progestin receptor and the following histological parameters: cellular pattern, cell density, n…
Assessment of DNA-protein crosslinks in the course of aging in two mouse strains by use of a modified alkaline filter elution applied to whole tissue…
1999
Abstract Two different mouse strains have been used for determination of age dependence of DNA-protein crosslinks by alkaline filter elution: a long lived laboratory strain, NMRI and an accelerated senescence-prone, short lived strain, SAMP1. Five organs were selected: Brain, kidney, lung, heart and liver. Remarkably in all five organs of short lived SAMP1 mice crosslinks increased significantly with age. In NMRI however only in brain and heart a significant rise in old age has been observed, while in the other organs there was no increase in DNA-protein crosslinking. Appreciable mitotic activity which is lacking in brain and heart could be the reason for this difference. Poor repair in all…
Chromosomes of the Parasitic Isopod Anilocra Physodes
1996
AbstractCounts of mitotic chromosomes have allowed to determine 2n = 12 as the modal diploid number of Anilocra physodes. Application of the C-banding technique reveals that two hetero-chromatic blocks bordering the centromeric region occur in each chromosome. This supports the notion that the actual low chromosome number of A. physodes may have been derived through a process of Robertsonian fusion.
Neuronal cell cycle: the neuron itself and its circumstances.
2015
Neurons are usually regarded as postmitotic cells that undergo apoptosis in response to cell cycle reactivation. Nevertheless, recent evidence indicates the existence of a defined developmental program that induces DNA replication in specific populations of neurons, which remain in a tetraploid state for the rest of their adult life. Similarly, de novo neuronal tetraploidization has also been described in the adult brain as an early hallmark of neurodegeneration. The aim of this review is to integrate these recent developments in the context of cell cycle regulation and apoptotic cell death in neurons. We conclude that a variety of mechanisms exists in neuronal cells for G1/S and G2/M check…
Early induction of genetic instability and apoptosis by arsenic in cultured Chinese hamster cells
2002
In order to assess at what time from the beginning of exposure inorganic arsenic can give rise to genetic instability and trigger apoptosis, V79-C13 Chinese hamster cells were treated with 10 microM sodium arsenite for 24 h. Under these conditions, cell survival was >70% and cells showed neither an increase in chromosome aberration frequency nor a delay in cell cycle progression. Investigations, which were carried out every 6 h during the treatment, revealed an early appearance of genetically unstable cells, namely micronucleated, multinucleated and mononucleated 'giant' cells, as well as apoptotic cells. Indirect immunostaining using anti-beta-tubulin antibody showed severe alterations in …
The role of Aurora-A inhibitors in cancer therapy
2007
Recently, new chemotherapy agents which target the non-structural components of mitosis have been developed. An important protein involved in several mitotic phases is the Aurora-A protein. By means of the phosphorylation of different substrates, Aurora-A regulates the correct development of the various phases of mitosis. The kinase activity of this protein makes Aurora-A an excellent candidate as an oncogene. The first data of Aurora-A involvement in cancer regarded the identification of Aurora-A overexpression in primary breast and colon tumour samples. With regard to the predictive role of Aurora-A, it has been shown that its overexpression disrupts the spindle checkpoint activated by pa…
Multiple-chromosome sex systems in the darkling beetles Blaps gigas and Blaps gibba (Coleoptera, Tenebrionidae)
1996
We have studied mitotic and meiotic chromosomes in the males of two species of Blaps: B. gigas and B. gibba. Karyological characteristics such as the occurrence of a multivalent configuration at diakinesis and two types of metaphase-II spreads support the notion that multiple-chromosome sex systems involving five chromosomes in B. gigas and eight chromosomes in B. gibba have developed in these species. Results obtained by means of silver staining and C-banding techniques suggest that the complex sex systems occurring in B. gigas and B. gibba may have originated from exchanges of terminal ribosomal genes among the Y chromosome and some autosomes.
Transcriptomic Changes Following Partial Depletion of CENP-E in Normal Human Fibroblasts
2021
The centromere is a fundamental chromosome structure in which the macro-molecular kinetochore assembles and is bound by spindle microtubules, allowing the segregation of sister chromatids during mitosis. Any alterations in kinetochore assembly or functioning or kinetochore–microtubule attachments jeopardize chromosome stability, leading to aneuploidy, a common feature of cancer cells. The spindle assembly checkpoint (SAC) supervises this process, ensuring a faithful segregation of chromosomes. CENP-E is both a protein of the kinetochore and a crucial component of the SAC required for kinetochore–microtubule capture and stable attachment, as well as congression of chromosomes to the metaphas…
Phase I Assessment of New Mechanism-Based Pharmacodynamic Biomarkers for MLN8054, a Small-Molecule Inhibitor of Aurora A Kinase
2011
Abstract The mitotic kinase Aurora A is an important therapeutic target for cancer therapy. This study evaluated new mechanism-based pharmacodynamic biomarkers in cancer patients in two phase I studies of MLN8054, a small-molecule inhibitor of Aurora A kinase. Patients with advanced solid tumors received MLN8054 orally for 7 consecutive days in escalating dose cohorts, with skin and tumor biopsies obtained before and after dosing. Skin biopsies were evaluated for increased mitotic cells within the basal epithelium. Tumor biopsies were assessed for accumulation of mitotic cells within proliferative tumor regions. Several patients in the highest dose cohorts showed marked increases in the ski…