Browsing by Subject "Cytogenetics"

Now showing 1 - 4 of 4
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    Angiofibroma of soft tissue: Current status of pathology and genetics
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2022) Nakayama, Shizuhide; Nishio, Jun; Aoki, Mikiko; Koga, Kaori; Nabeshima, Kazuki; Yamamoto, Takuaki
    y. Angiofibroma of soft tissue (AFST) is a new soft tissue tumor entity described in the 2020 World Health Organization Classification of Soft Tissue and Bone Tumors. It most often arises in the lower extremities of middle-aged adults and pursues a benign clinical course with a low rate of non-destructive local recurrence. Histologically, the lesion consists of uniform bland spindle cells in a fibromyxoid stroma with a prominent vascular network. The vascular component forms a complex arrangement of small, thin-walled branching blood vessels. By immunohistochemistry, AFST is variably positive for epithelial membrane antigen, desmin, smooth muscle actin, CD34, CD68, CD163 and estrogen receptor. The exact etiology of AFST remains unknown, but it appears genetically distinct, with a balanced t(5;8)(p15;q13) translocation resulting in a fusion of aryl hydrocarbon receptor repressor (AHRR) and nuclear receptor coactivator 2 (NCOA2). Knowledge of this recently described entity is important because it can mimic a variety of intermediate and malignant soft tissue tumors, including solitary fibrous tumor, low-grade fibromyxoid sarcoma, myxoid liposarcoma and low-grade myxofibrosarcoma. We review AFST, with an emphasis on the diagnostic spectrum, recent molecular genetic features and the differential diagnosis.
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    Cytogenetic analysis and morphology of malignant nuclear vlimata. The life cycle of malignant cells
    (Murcia : F. Hernández, 1994) Logothetou-Rella, H.
    The karyotype of malignant nuclear vlimata (NVs) was investigated with the in situ and chromosomal spreading techniques. NV metaphases were recognised by the head with tail morphology, kept in situ and evaluated by the chromosomal spreading technique. It was shown that malignant NVs were produced by random, uncontrolled meiosis. NVs contain and carry single, hypodiploid, haploid, hypohaploid, hyperdiploid and atypical sets of chromosomes. NVs are unstable parasitic cellular elements, invading the cytoplasm or the nucleus of host cells, extruding and implanting their chromosomes in the host cell upon contact. Within a malignant cell culture, NVs play the role of chromosomal donors and host cells of chromosomal recipients. NVs were identified as episomatic on host cell nuclei or incorporated into host cell metaphases. The observations are discusssed in terms of fertilization, vira1 infection and apoptosis. Comparison of malignant NVs with phytohaemagglutinin (PHA)-activated lymphocytic NVs is provided, as well as the life cycle of the malignant cells as follows: meiosis invasion Malignant cell - NVs - recipient host cell - hybrid cells NVs formation
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    Differentiation of human lymphocytes into nuclear vlimata by meiosis. The cytotoxic effect of calcium-activated neutral proteinase inhibitor
    (Murcia : F. Hernández, 1994) Logothetou-Rella, H.
    Phytohaemagglutinin (PHA)-activated lymphocytes differentiated into nuclear vlimata (NVs) in vitro. Lymphocyte attachment was followed by formation and extrusion of cytoplasmic vesicles. nuclear elongation and fragmentation into NVs. NVs and cytoplasmic vesicles were detached and organized into large cell nodules in suspension. Immunocytochemistry showed that T-lymphocytes differentiated mainly to NVs while B-lymphocytes to buds. During differentiation there was a loss or gain of T-antigenicity by either mother or daughter cell. Cytogenetic analysis by chromosomal spreading and in situ techniques showed that NVs do carry chromosomes of hypodiploid or hypohaploid sets. NVs were the result of meiosis stimulated by PHA. A ly~nphocyticp opulation exhibited diploidies attributed to mitosis or symmetrical meiosis and hypodiploidies, hypohaploidies attributed to meiosis. A comparison between NVs and spermatozoa was provided. The inhibitor of calcium-activated neutral proteinase (CANP-I) was cytotoxic to NVs without interfering with NV production. A model was proposed for the action of CANP-I which is a promising agent against autoimmune diseases.
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    Nuclear vlimata and aneuploidy in embryonic cells is caused by meiosis. Behaviour and properties of meiotic cells
    (Murcia : F. Hernández, 1995) Logothetou-Rella, H.
    This study demonstrates that human embryonic cells divide by meiosis. The use of trophoblastic tissue cells (early embryo) and amniotic cells (late embryo) exhibited the following characteristic events of meiosis: nuclear (NVs) and nucleolar (NuVs) vlimata formation; NV invasion in host cells; extrusion of chromosomes; nuclear fusion; metaphase fusion; hybrid cell formation; nuclear, nucleolar and cytoplasmic bridges, chromosomal transfer, variablesized nuclei; nuclear fragmentation; condensed meiotic chromosomes; "0" chromosome; and aneuploidy. Two types of nuclear bridges (NBs) were identified and defined as communicative tubules through which chromosomal transfer among cells is achieved. The wall of NBs is an extension of the nuclear membrane and the lumen contained chromosomal fusion substance (CFS). Embryonic cells formed glycosaminoglycan-sacs (GSGsacs) and rivulets, forming a cytoplasmic communicative system. The extracellular matrix (ECM), GSG-sacs and CFS were composed of glycosaminoglycan-bound protease. The protease which immuno-crossreacted with the al-chymotrypsin antiserum was the meiotic calciumactivated neutral proteinase (CANP). Cytogenetic analysis of early embryonic cells showed higher ratio of aneup1oidy:diploidy than late embryonic cells. The results are discussed in terms of differentiation-mitosis and undifferentiation-meiosis. These observations lead to an embryonic cell life cycle identical to that of malignant cells as follows: meiosis invasion Zygote & NVs and NuVs - recipient host nuclear fusion cells - hybrid cells-w organogenesis metaphase fusion + mitosis