• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.143-150
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• 1996

Tumor masses from a Bengal tiger (Panthera tigris) of 13 years in age raised at the natural farm in Yong-In were examined grossly and microscopically. The tumors were observed in the subcutis, lung, heart, liver, pancreas, kidney, cecum and spleen. Histologically the tumors were composed of solid anaplastic cells that formed mature or immature small blood vessels and invaded the adjacent parenchyma. The nuclei of the tumor cells were large, vacuolated, and round or ovoid, sometimes dense and ovoid or spindle. The mitotic figures were common and the boundaries between the cells were indistinct. The stroma was very sparse. A diagnosis of this case was made as hemangiosarcoma on the basis of gross and microscopic features.

• Molecules and Cells
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• v.27 no.2
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• pp.135-142
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• 2009

The centrosome, an organelle comprising centrioles and associated pericentriolar material, is the major microtubule organizing center in animal cells. For the cell to form a bipolar mitotic spindle and ensure proper chromosome segregation at the end of each cell cycle, it is paramount that the cell contains two and only two centrosomes. Because the number of centrosomes in the cell is determined by the number of centrioles, cells have evolved elaborate mechanisms to control centriole biogenesis and to tightly coordinate this process with DNA replication. Here we review key proteins involved in centriole assembly, compare two major modes of centriole biogenesis, and discuss the mechanisms that ensure stringency of centriole number.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.162.2-162.2
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• 2003

Microtubule-organizing center (MOTC) plays pivotal roles in cell division process. Integrity of the spindle pole body (SPB) in Saccharomyces cerevisiae is required for migration and separation of sister chromatids in mitotic phase. Role of an essential SPB component, Spcl05, is poorly understood. Here we show that throughout all stage of cell division cycle, GFP-tagged Spcl05p localizes at SPB and its protein stability is fluctuated with mitosis-specific modifications. To gain new insights into the function of Spc105, we generated and characterized novel temperature sensitive spc105 mutants. (omitted)

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.2
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• pp.112-117
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• 2010

Aurora kinases represent a novel family of serine/threonine kinases crucial for cell cycle control. Aurora-2 kinase is mainly involved in centrosome function, mitotic entry, and spindle assembly. Aurora-2 kinase overexpression causes centrosome amplification and the formation of multipolar mitotic spindles, which leads to tumor aneuploidy and so it has been found to play an important role in tumorigenicity in many cancers such as colorectal cancer, breast cancer and cervical cancer. Hence, the goal of this study is to identify the correlation of clinicopathlogical factors and overexpression of Aurora-2 kinase in oral squamous cell carcinoma. We studied the immunohistochemical staining of Aurora-2 kinase in 20 specimens of 20 patients with oral squamous cell carcinoma and the relationships between Aurora-2 kinase over expression and each of the clinico-pathological parameters were analyzed by Pearson correlation analysis. Statistical significance was set at P < 0.05. The results were as follows. 1. In the immunohistochemical study of poorly differentiated and invasive oral squamous cell carcinoma, the high level staining of Aurora-2 kinase was observed. 2. The correlation between immunohistochemical Aurora-2 kinase expression and histopathological differentiation of specimens was significant. These findings suggest that overexpression of Aurora-2 kinase may play a important role in carcinogenesis of oral squamous cell carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1389-1393
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• 2012

Objective: To discuss the significance of DOG1, CD117 and PDGFRA in the diagnosis of gastrointestinal stromal tumors (GISTs), and analyze their correlations with clinicopathological features and risk ranking. Method: DOG1, CD117 and PDGFRA were detected with IHC Envision ldpe-g-nvp in 63 GISTs and 43 cases of non-GISTs, and analyzed for relations with clinicopathological factors (gender, age, location, tumor size, mitotic phase, histology) and risk degree. Results: The positive expression rate of DOG1, CD117 and PDGFRA in GISTs was 84.1% (53/63), 90.5% (57/63), 53.2% (33/63), respectively. Among the 6 CD117 negative cases, all were DOG1 positive and 5 were PDGFRA positive. Rates in patients with non-GISTs was 11.6%, 16.3%, 6.98%, respectively. Expression of DOG1 and PDGFRA demonstrated no significant variation with gender, age, position, tumor size, mitotic phase, histology, and risk rank. However, CD117 was related with position and histology (P=0.008 and P=0.045), those in the mesentery having a higher positive rate than those derived from stomach, small intestine, colon and rectum (50.0% vs 94.7%, P=0.008). Furthermore CD117 was also highly expressed in spindle and epithele types. Conclusions: DOG1 had a good sensitivity and specificity as a kind of newly discovered marker, especially for KIT negative GISTs. However, DOG1, CD117 and PDGFRA cannot be used for assessing the rish of patients.

• Korean Journal of Poultry Science
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• v.23 no.1
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• pp.1-7
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• 1996

In order to produce polyploid quail, the patterns of spermatogenesis and induction of diploid spermatozoa were analyzed by administration of spindle fiber inhibitor agent. Colcemid at the dose level of 37 $\mu\textrm{g}$ /100 g BW was Injected intraperitoneally to 50 Japanese quail males for 3 consecutive days. Five to 20 days after the first colcemid injection, the metaphase spreads from mitotic spermatogonia, primary spermatocyte and secondary spermatocyte were observed. By cytogenetic analysis, 9.4％ of spermatogonia and spermatocyte cells in germ cells from the treated males was found to be polyploid cells. As compared with colcemld treated, the males with non-treated colcemid had only 2.3％ polyploid cells in germ cells. The induction of diploid germ cells was highest in 10 days after the first colcemid injection and was lowest in 5 days after the first colcemid injection. These results suggested that between 10 to 15 days before maturation of the spermatozoa, the male germ cells were most sensitive to colcemid treatment. Spindle fiber inhibitor agent was also more sensitive to mitotic division of spermatogonia than meiotic division of primary and secondary spermatocyte.

• Journal of Life Science
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• v.32 no.2
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• pp.161-166
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• 2022

Mitosis is a process in which a replicated genome is distributed to two daughter cells, and it is necessary for cell survival and organismal development. During mitosis, the spindle assembly checkpoint (SAC) ensures faithful chromosome segregation by monitoring the kinetochore attachment to the mitotic spindle. Although the SAC mechanism has been extensively studied over the last 30 years, the mechanism by which a single unattached kinetochore activates the SAC remains unclear. The key components of the SAC are Mad1, Mad2, Mad3 (BubR1 in higher eukaryotes), Bub1, Bub3, and Cdc20, which are all required for SAC activation. An essential step for SAC activation is the formation of the Mad2 - Cdc20 complex in the unattached kinetochore, which is kinetically disfavored. Although the mechanism by which Mad2 and Cdc20 are recruited to unattached kinetochores is well-known, it is not clear how they form a complex. Recently, a key mechanism for the formation of the Mad2 - Cdc20 complex has been identified, which is catalyzed by an unattached kinetochore. This supports the evidence that a single unattached kinetochore can activate the SAC signaling. Herein, we discuss the known key mechanism for SAC activation, review the recent studies on SAC, and conclude how their discoveries improved the understanding of mitosis.

• Journal of Life Science
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• v.33 no.11
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• pp.950-955
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• 2023

Cell division is an essential process for the survival and development of living organisms. It is critical that duplicated chromosomes are properly segregated into daughter cells during mitosis. The centrosome is the core organelle that forms the microtubule-organizing center (MTOC), which generates the microtubules that make up the mitotic spindle during cell division. The centrosome is also involved in cell signaling and motility. In normal cells, there is one centrosome in G1 that replicates into two in the S phase and matures through G2. During the M phase, duplicated centrosomes move to both ends of the cell, and spindle microtubules that are generated from MTOC move the chromosome to both ends. The cells then split into two to complete the cell division. However, a phenomenon called centrosome amplification (CA), in which the number of centrosomes is higher than normal, is common in cancer cells and can lead to chromosome instability (CIN). This paper discusses the process of centrosome replication and the role of PLK4 in this process. The possible consequences of centrosome amplification and how the PLK4 inhibitor may be able to treat certain types of cancer cells, such as breast cancer and neuroblastoma, will also be discussed.

• Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.107-114
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• 2006

A dermal sarcoma was found in a freshwater, soft-shelled turtle Pelodiscus sinensis. The neoplasm consisted of proliferating fibrous tissue and extended from the dermis. The overlying epidermis was hyperplastic and partially folded. The deeper dermis and hypodermis contained three large, discrete necrotic foci of -10 mm diameter. Numerous eosinophilic granule cells and macro phages surrounded the necrotic areas. A mixed population of cells with nuclear pleomorphism was observed between the papillary layers of vessels. This area also had regions of different histological structures: (l) regularly arranged, spindle-shaped cells with compact nuclei in a fine-fibrillar matrix; (2) haphazardly arranged cells ($\leq$ 23 11m diameter) with ovoid, highly hypertrophic, faintly stained nuclei; and (3) cells (3.6-5.8 11m diameter) with irregularly shaped nuclei and marginal condensed chromatin in a myxomatous matrix. Some mitotic figures, binucleate cells, and multinucleate giant cells of up to 50 11m in length were also found. Flow cytometry of propidium iodide-stained cells yielded different histograms for the normal skin and the skin (primarily epidermis) and fibrous dermis of the tumor, indicating DNA heterogeneity in the dermal portion of the tumor. The ploidy indices for the dermal cells were 1.91 and 0.78, as compared to normal cells.

• Clinical and Experimental Pediatrics
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• v.51 no.1
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• pp.98-101
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• 2008

Leiomyosarcoma is an uncommon soft tissue sarcoma of mesenchymal cell origin, which shows smooth muscle differentiation. Leiomyosarcoma is seldom found in the pediatric population, and accounts for fewer than 2% of all soft tissue sarcomas. Leiomyosarcoma of the chest wall is extremely rare in children. We report here a case of an 8-year-old boy with a primary leiomyosarcoma that was incidentally found as a rib mass. The patient underwent a complete resection for a suspected osteochondroma diagnosed by a three-dimensional chest computed tomography examination. Pathological findings of the mass revealed intersecting fascicles of spindle cells showing cigar-shaped nuclei, inconspicuous nuclear pleomorphism and occasional mitotic figures in the background of a suspected osteochondroma of the rib. This report documents the first description of a leiomyosarcoma possibly arising in an osteochondroma of the rib in a child.