• 생명과학회지
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• 제20권4호
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• pp.519-527
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• 2010

Paclitaxel은 미세소관의 탈중합을 억제하는 시약으로 알려져 있다. Paclitaxel은 다양한 세포에서 세포 내 방추체를 안정화시킴으로써 유사분열 억제 및 세포사멸을 유도한다. 본 실험에서는 토끼 관절 연골세포에서 paclitaxel이 연골세포의 증식과 사멸에 미치는 효과에 대한 연구를 수행하였다. MTT assay를 수행한 결과 paclitaxel은 연골세포에서 농도 의존적으로 세포 증식을 억제한다는 것을 확인 할 수 있었으며, FACS analysis와 Western blot analysis를 수행한 결과, paclitaxel이 G2/M 정지를 유도하는 것을 확인하였다. 또한, paclitaxel이 비정상적인 세포 분열유도와 핵 단편분절 유도없이 일어나는 mitotic catastrophe 즉, caspase-3 비의존적인 세포사멸을 유도하였다. Paclitaxel을 처리한 세포에서 일어나는 이러한 mitotic catastrophe에 의한 세포 죽음은 G1/S기의 진행을 억제하는 시약인 thymidine을 처리하는 것에 의해 억제되는 것을 확인할 수 있었다. 이러한 결과를 종합해 볼 때, paclitaxel에 의한 토끼 관절 연골 세포에서의 세포 죽음은 caspase-3 비의존적인 mitotic catastrophe에 의해 일어나는 것으로 사료되어진다.

• 한국수의병리학회지
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• 제2권2호
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• pp.127-138
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• 1998

Transmissible venereal tumor(TVT) is a naturally occurring contagious neoplasm which can be transmitted by mechanical contact during mating in dogs and transplanted as intact viable cells to dogs and other members of canine family such as coyotes, jackals, wolves, and foxes. The incidence of this tumors tends to increase in Korean native Jindo dogs. This is probably due to the high density and unrestrained management system. With time, TVT reaches the maximum size and then tends to regress spontaneously unless individuals are immunologically compromised. It consists of different types of cells depending on the stage. In this study, 10 tumors were selected from Jindo dogs. These were histologically calssified into three stages; progressive, steady-state, and regressive. Mitotic figures were counted, and their histological appearance at each stage is compared with their DNA ploidy. Histologically, 5 tumor cases were calssed as the progressors, 3 cases as the steady-state tumors, and 2 cases as regressors. Progressors were composed of round cells with large nuclei containing conspicuous nucleoli and frequent mitotic figures. A few spindle-shaped cells and inflammatory cells including mainly lymphocytes, a few neutrophils and macrophages were also seen. In the steady-state tumors, there was an increased number of spindle shaped cells and mitotic figures were rare. Six tumors were diploid and four were aneuploid with the variation coefficient of 7.02. Two of five progressive tumors were aneuploid. Two of three steady-state tumors were aneuploid while both tumors at the regressive stage were diploid. Progressive and steady-state tumors had a much larger S/G2M fraction and a higher mitotic index than regressive tumors. Two tumors which persisted for more than one year were aneuploid. These results suggest that the progressive and steady-state tumors had more active cell division than the regressive neoplasms.

• Reproductive and Developmental Biology
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• 제34권2호
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• pp.73-79
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• 2010

We investigated the microtubule dynamics, including the inheritance of donor centrosomes and the mitotic spindle assembly occurring during the first mitosis of somatic cell nuclear transfer (SCNT) embryos in pigs. SCNT embryos were fixed 15 min and 1 h after fusion in order to assess the inheritance pattern of the donor centrosome. The distribution and dynamic of the centrosome and microtubule during the first mitotic phase of SCNT embryos were also evaluated. The frequency of embryos evidencing $\gamma$-tubulin spots (centrosome) was 93.2% in the SCNT embryos 15 min after fusion. In the majority of the SCNT embryos (61.5%), however, no centrosome was observed 1 h after fusion. The frequency of the embryos with no or abnormal mitotic spindles 20 h after fusion was 19.6%. The $\gamma$-tubulin spots were detected near the nuclei of somatic cells regardless of cell cycle phase, whereas $\gamma$-tubulin spots in the SCNT embryos were observed only during the inter-anaphase transition. These results showed that the donor centrosome is inherited into the SCNT embryos, but failed to assemble the normal mitotic spindles during first mitotic phase in some SCNT embryos.

• 한국균학회지
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• 제24권1호통권76호
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• pp.1-7
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• 1996

느타리버섯균의 이핵체 체세포 균사에서 분열전 및 분열후의 핵과 분열중의 핵을 화학고정방법과 동결교체방법을 이용하여 균사분화과정중의 성상체 미세소관의 미세구조적 동태를 조사하였다. 많은 수의 성상체 미세소관들이 이동중인 분열전의 핵들과 연관되어 있었으며, 분열전의 핵이 이동하는 시기에 SPB의 분리가 진행됨이 발전되었다. 분열전 이동중의 핵과는 대조적으로 SPB의 분리가 더 이상 일어나지 않는 분열중의 이거나 분열이 끝난 핵에서는 성상체미세소관이 덜 발달되어 있었다. 활발히 이동할 것으로 추측되는 분열후의 핵에서 핵과 연관된 성상체미세소관이 잘 발달되어 있지 않음은 특이한 점이다. 분열중의 모든 핵에서 성상체미세소관이 SPB에서 뻗어나오며 인은 핵막에 남아있다. 핵의 분열과 핵의 이동 및 SPB의 분리와 관련된 성상체미세소관의 기능에 대하여 논의하였다.

• 한국잡초학회지
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• 제12권3호
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• pp.261-270
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• 1992

Many herbicides that are applied at the soil before weed emergence inhibit plant growth soon after weed germination occurs. Plant growth has been known as an irreversible increase in size as a result of the processes of cell divison and cell enlargement. Herbicides can influence primary growth in which most new plant tissues emerges from meristmatic region by affecting either or both of these processes. Herbicides which have sites of action during interphase($G_1$, S, $G_2$) of cell cycle and cause a subsequent reduction in the observed frequency of mitotic figures can be classified as an inhibitor of mitotic entry. Those herbicides that affect the mitotic sequence(mitosis) by influencing the development of the spindle apparatus or by influencing new cell plate formation should be classified as causing disruption of the mitotic sequence. Sulfonylureas, imidazolinones, chloroacetamides and some others inhibit plant growth by inhibiting the entry of cell into mitosis. The carbamate herbicides asulam, carbetamide, chlorpropham and propham etc. reported to disrupt the mitotic sequence, especially affecting on spindle function, and the dinitroaniline herbicides trifluralin, nitralin, pendimethalin, dinitramine and oryzalin etc. reported to disrupt the mitotic sequence, particularly causing disappearence of microtubles from treated cells due to inhibition of polymerization process. An inhibition of cell enlargement can be made by membrane demage, metabolic changes within cells, or changes in processes necessary for cell yielding. Several herbicides such as diallate, triallate, alachlor, metolachlor and EPTC etc. reported to inhibit cell enlargement, while 2, 4-D has been known to disrupt cell enlargement. One potential danger inherent in the use of soil acting herbicides is that build-up of residues could occur from year to year. In practice, the sort of build-up that would be disastrous is unikely to occur for substances applied at the correct soil concentration. Crop injury caused by soil applied herbicides can be minimized by (1) following the guidance of safe use of herbicides, particularly correct dose at correct time in right crop, (2) by use of safeners which protect crops against injury without protecting any weed ; interactions between herbicides and safeners(antagonists) at target sites do occur probably from the following mechanisms (1) competition for binding site, (2) circumvention of the target site, and (3) compensation of target site, and another mechanism of safener action can be explained by enhancement of glutathione and glutathione related enzyme activity as shown in the protection of rice from pretilachlor injury by safener fenclorim, (3) development of herbicide resistant crops ; development of herbicide-resistant weed biotypes can be explained by either gene pool theory or selection theory which are two most accepted explanations, and on this basis it is likely to develop herbicide-resistant crops of commercial use. Carry-over problems do occur following repeated use of the same herbicide in an extended period of monocropping, and by errors in initial application which lead to accidental and irregular overdosing, and by climatic influence on rates of loss. These problems are usually related to the marked sensitivity of the particular crops to the specific herbicide residues, e.g. wheat/pronamide, barley/napropamid, sugarbeet/ chlorsulfuron, quinclorac/tomato. Relatively-short-residual product, succeeding culture of insensitive crop to specific herbicide, and greater reliance on postemergence herbicide treatments should be alternatives for farmer practices to prevent these problems.

• BMB Reports
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• 제48권7호
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• pp.413-418
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• 2015

DEPDC1 is a recently identified novel tumor-related gene that is upregulated in several types of cancer and contributes to tumorigenesis. In this study, we have investigated the expression pattern and functional implications of DEPDC1 during cell cycle progression. Expression studies using synchronized cells demonstrated that DEPDC1 is highly expressed in the mitotic phase of the cell cycle. Immunofluorescence assays showed that DEPDC1 is predominantly localized in the nucleus during interphase and is redistributed into the whole cell upon nuclear membrane breakdown in metaphase. Subsequently, siRNA-mediated knockdown of DEPDC1 caused a significant mitotic arrest. Moreover, knockdown of DEPDC1 resulted in remarkable mitotic defects such as abnormal multiple nuclei and multipolar spindle structures accompanied by the upregulation of the A20 gene as well as several cell cycle-related genes such as CCNB1 and CCNB2. Taken together, our current observations strongly suggest that this novel cancerous gene, DEPDC1, plays a pivotal role in the regulation of proper mitotic progression. [BMB Reports 2015; 48(7): 413-418]

• 대한수의학회지
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• 제35권2호
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• pp.375-381
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• 1995

Two intraocular tumors were identified in low and medium dosed groups of a carcinogenicity study using 200 males and 200 females Sprague-Dawley rats in Screening & Toxicology Research Center, Korea Research Institute of Chemical Technology. The tumors were grossly observed as white or yellow, unilateral nodules. They were approximately $1-2{\times}3-5mm$ in size. The tumors located in the region of iris and/or ciliary body invaded peripheral cornea. The microscopic features were usually composed of spindle cells arranged in parallel, forming gently curving bundles or whorls. The spindle cells had poorly defined cell boundaries, scant to moderate cytoplasm, fusiform nuclei and indistinct nucleoli. Mitotic figures were rare and areas of necrosis were present. The spindle cells had positive immunoreactivity for S-100 protein and vimentin but negative for desmin, collagen and HMB-45 antibody. In special histochemical studies, the spindle cells react with Gomori's stain for argyrophih fibers, Prussian blue stain for iron but negative with Masson-Fontana's stain for melanin granules. Ultrastructurally, cytoplasmic premelanosomes were not observed in the tumor cells due to the poor preservation of tumor masses. Based on the results, the tumors were diagnosed as amelanotic melanoma.

• Applied Microscopy
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• 제33권2호
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• pp.105-116
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• 2003

U. unicinctus 난세포를 인공수정한 결과 수정 시기는 germinal vesicle (2n)기였으며 정자 중앙부에서 돌출한 actomere와 난모세포의 미세융모 끝에서 세포막 융합이 시작되는 것으로 관찰되었다. Germinal vesicle기에 수정이 가능하였으므로 pre-mitotic spindle이 관찰되지 않은 것으로 사료되었다. 수정 후 난모세포는 제1, 2감수분열을 수행하였으며 각각의 감수분열 장치들은 감수분열 말기에 난모세포막과 밀접한 구조를 형성하였고, 이 부위에서 극체가 형성되는 것을 볼 수 있었다. 극체 형성시 난모세포막은 세포분열의 관점에서 형태가 없는 것이 아니라 항-튜블린-FITC에 대한 활성구조를 형성하였으며, 각 감수분열 장치의 한쪽 극 (pole)과 어떤 복합구조를 형성하는 것으로 보인다. 제2극체 형성도 제1극체와 유사한 방법으로 형성되었으나, 제2감수분열 장치는 난모세포막의 접선에 평행하게 생성된 후 세포막을 향해 이동하면서 방추사의 양극성이 회전 (shift-rotation)하였고 접선에 수직으로 정렬하는 것을 볼 수 있었다. 난모세포의 감수분열 장치에서 방추사의 활성은 강하였으나 aster의 활성은 비교적 약한 것으로 보였다. 제2감수분열이 진행되는 동안 난모세포질에 머믈고 있던 정자는 점차 미래의 자성 전핵 형성부인 난모세포막 근접부로 이동하는 것이 관찰되었다. 난모세포막 근접부로 이동하는 동안 정자 aster의 활성은 점차 강해지는 반면 난모세포의 aster에서는 활성이 미약한 것으로 보아서 자웅 전핵융합을 주도하는 것은 정자 유래의 aster인 것으로 사료되었다. 제1난모세포의 감수분열 장치가 활성화되는 시기에 제1극체의 방추사에서도 강한 활성을 관찰할 수 있었다.

• 대한세포병리학회지
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• 제1권2호
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• pp.158-163
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• 1990

Ancient (degenerated) schwannomas are benign tumors that display pronounced degenerative changes including cyst formation, calcification, hemorrhage, and hyalinization. The tumors are usually infiltrated by large numbers of inflammatory cells such as neutrophils, lymphocytes, siderophages, and histiocytes. They are located in deep locations such as the retroperitoneum and must be differentiated from malignant soft tissue tumors because spindle cells with nuclear atypia may be present. In the fine needle aspiration biopsy. The cytologic findings of two cases of ancient schwannoma occurring in posterior mediastinum and retroperitoneum, respectively, are described. Computerized tomographic findings of both cases showed changes of cystic degeneration or necrosis. A case occurred in retroperitoneum revealed features of destruction of vertebral body to suggest a malignant soft tussue tumor radiologically. The cytologic findings of aspiration biopsy of both tumors revealed that the tumor cells were spindle in shape with elongated nuclei. Some of tumor cells were arranged in a palisading fashion. Cell structures that resemble the Verocay bodies were observed. Some of the tumor cells showed pleomorphic bizarre nuclei, but no mitotic activity or chromatin clumping was seen. Inflammatory cells, siderophages and histiocytes were scattered in fibrillar material. These cytologic findings are important in the diagnosis of ancient schwannoma and in the differentiation of this tumor from the malignant spindle cell tumor.

• 한국임상수의학회지
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• 제33권5호
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• pp.316-319
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• 2016

A 12-year-old thoroughbred mare with four days history of anorexia and high fever was submitted to the Equine Hospital. She failed to conceive in the following the breeding season in spring. In rectal palpation, mass could be palpable surrounding ovary. Because of the poor prognosis, full necropsy for mare was decided. The mass is located between right large and small colon, cranial to ovary using ultrasonography. Grossly, the mass was about $5{\times}3.5{\times}4cm$ in size, and the cut surface of mass showed brownish yellow in color with red-to orange granular areas Histopathologically, neoplastic cells were mixed with well differentiated spindle shape cells arranged in interlacing, interwoven pattern and poorly differentiated spindle cells. Neoplastic cells had abundant pink cytoplasm and bland and cigar-shaped nuclei with low mitotic figures. Many arteriole-like blood vessels with thick muscular wall were present throughout the mass. Masson's trichrome staining revealed muscle origin tumors in this case. Immunohistochemically, the neoplastic spindle cells showed positive reactions for smooth muscle actin and desmin. In our best knowledge, this is the first report of uterine angioleiomyoma in mare in Korea.