• Clinical and Experimental Reproductive Medicine
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• v.49 no.2
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• pp.101-109
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• 2022

Objective: Y chromosome microdeletions are the second most common genetic cause of male infertility after Klinefelter syndrome. The aim of this study was to determine the patterns of Y chromosome microdeletions among infertile Mongolian men. Methods: A descriptive study was performed on 75 infertile men from February 2017 to December 2018. Y chromosome microdeletions were identified by polymerase chain reaction. Semen parameters, hormonal levels, and testis biopsy samples were examined. Results: Among 75 infertile men, two cases of Y chromosome microdeletions were identified. The first case had an AZFa complete deletion and the other had an AZFc partial deletion. This study found that the proportion of Y chromosome microdeletions among infertile Mongolian men was 2.66%. Conclusion: The findings can be applied to in vitro fertilization and assisted reproductive technology, and our results will help clinicians improve treatment management for infertile Mongolian couples.

• Molecules and Cells
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• v.37 no.10
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• pp.713-718
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• 2014

Alteration in chromosome numbers and structures instigate and foster massive genetic instability. As Boveri has seen a hundred years ago (Boveri, 1914; 2008), aneuploidy is hall-mark of many cancers. However, whether aneuploidy is the cause or the result of cancer is still at debate. The molecular mechanism behind aneuploidy includes the chromosome mis-segregation in mitosis by the compromise of spindle assembly checkpoint (SAC). SAC is an elaborate network of proteins, which monitor that all chromosomes are bipolarly attached with the spindles. Therefore, the weakening of the SAC is the major reason for chromosome number instability, while complete compromise of SAC results in detrimental death, exemplified in natural abortion in embryonic stage. Here, I will review on the recent progress on the understanding of chromosome missegregation and cancer, based on the comparison of different mouse models of BubR1, the core component of SAC.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.128-133
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• 1998

Analyses of now karyotypes using different maize (Zea mays L.) inbred lines have been performed. The accumulation and isolation of high quality and quantity metaphase chromosomes from root tips can be achieved from many kinds of maize lines. The chromosome suspensions were prepared by a simple slicing method from synchronized maize root tips and analyzed with a now cytometry. The variations of experimental now karyotypes were detected among inbred lines in terms of the positions and/or the numbers of chromosome peaks. The 2C DNA amount among 8 inbred lines ranged from 5.09 to 5.52 pg. The variability of DNA content in maize chromosome 1 was 9.1 % ranging from 0.685 to 0.747 pg. The selection of appropriate maize lines is critical for sorting specific single chromosome types. At least five different chromosome types can be discriminated and sorted from five maize lines.

• Environmental Mutagens and Carcinogens
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• v.11 no.2
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• pp.107-117
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• 1991

The effect of 3-aminobenzamide (3AB), an inhibitor of poly (ADP-ribose) polymerase, on ethyl methanesulfonate (EMS)-or bleomycin (BLM)-induced DNA repair synthesis and chromosome aberrations was examined during the cell cycle of Chinese hamster ovary (CHO)-K$_1$ cells. The synchronized cells were obtained by using thymidine double block method and mitotic selection method. Three assays were employed in this study: unscheduled DNA synthesis, alkaline elution and chromosome aberrations. 3AB alone did not induce DNA repair and chromosome aberrations in all phases. The post-treatment with 3AB inhibited DNA repair synthesis induced by EMS or BLM in G$_2$ phase, whereas 3AB did not affect chromosome aberrations induced by EMS or BLM in all phases. These results suggest that 3AB aggravates the cell cycle disturbance which occur after DNA damage, and leads to an accumulation of cells at G$_2$ phase, and inhibits DNA repair synthesis, while the effect 3AB on chromosome aberrations may need reevaluated.

• Clinical and Experimental Pediatrics
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• v.46 no.3
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• pp.291-294
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• 2003

Ring chromosome 21 causes a multitude of phenotypes, ranging from severe abnormalities to normal. The proposed mechanism of ring formation, breakage of both short and long arms of a chromosome with subsequent end to end fusion, remains unproven. We encountered a 4-year-old boy who presented developmental delay, microcephaly, micrognathia, hypertelorism, low-set ears, mild optic nerve hypoplasia, cleft lip and palate, scoliosis and left foot valgus, but normal brain MRI. Chromosome study from peripheral blood showed 46,XY, r(21)(p11.2q22.1) karyotype. The authors report the first case of ring chromosome 21 in Korea with a review of the literature.

• Korean Journal of Plant Taxonomy
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• v.50 no.3
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• pp.361-367
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• 2020

We report meiotic chromosome numbers of three taxa in Carex sect. Mitratae in Korea: Carex breviculmis R. Br. (n = 32_II, 33_II, 34_II), C. polyschoena H. Lév. & Vaniot (n = 37_II, 38_II), and C. sabynensis Less. ex Kunth (n = 27_II). Section Mitratae is one of the most species-rich Asian groups in Carex, comprising approximately 45-80 taxa. Twenty-seven of these occur in Korea, and they are some of the most challenging taxa to identify due to their obscure and inconspicuous diagnostic characters. Including the counts reported here, half of the native Korean sect. Mitratae chromosome numbers have been documented. Their haploid chromosome numbers range from n = 10 to n = 40, and many exhibit variations in the numbers counted within a taxon. These variations, along with the overall significant variation in sect. Mitratae, suggest that dynamic chromosome activity may be related to the high species diversity of Carex.

• The Korean Journal of Zoology
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• v.31 no.2
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• pp.104-110
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• 1988

The comparative karyological analysis of the Korean treefrog, Hyla japonica and Hyla suweonensis performed by conventional giemsa-staining and NOR-staining method. The karyotypes of both species were the same (2n=24). However, according to the Karyological analysis, the 6th chromosomes of the two species distinctly different. Eventhough the 6th chromosomes of the two species shown the same % length, construction of the 6th chromosome of H.japonica was subtelocentric chromosome while H. suweonensis was submetacentric chromosome. This phenomena could explain that the morphological differences in the 6th chromosomes might be caused by pericentric inversion. The two species have 1 pair of NOR site in the 6th chromosome.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.3-9
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• 2003

The task for chromosome analysis and diagnosis by experienced cytogenetists are being concerned as repetitive, time consuming job and expensive. For that reason, intelligent agent based on chromosome knowledge base has been established to be able to analyze chromosomes and obtain necessary advises from the knowledge base instead of human experts. That is to say, knowledge base by IF THEN production rule was implemented to a knowledge domain with normal and abnormal chromosomes, and then the inference results by knowledge base could enter the inference data into the database. Experimental data were composed of normal chromosomes of 2,736 patients 'cases and abnormal chromosomes of 259 patients' cases that have been obtained from GTG-banding metaphase peripheral blood and amniotic fluid samples. The completed intelligent agent for chromosome knowledge base provides variously morphological information by analysis of normal or abnormal chromosomes and it also has the advantage of being able to consult with user on chromosome analysis and diagnosis.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.06a
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• pp.215-222
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• 2001

The task for chromosome analysis and diagnosis by experienced cytogenetists are being concerned as repetitive, time consuming job and expensive. FOr that reason, chromosome analysis system based on knowledge base for CAI had been established to be able to analyze chromosomes and obtain necessary advises from the knowledge base instead of human experts. That s to say, knowledge base by IF THEN production rule was implemented to a knowledge domain with normal and abnormal chromosomes, and then the inference results by knowledge base could enter the inference data into the database. Experimental data were composed of normal chromosome of 2,736 patients'cases and abnormal chromosomes of 259 patients'cases that have been obtained from GTG-banding metaphase peripheral blood and amniotic fluid samples. The complete system provides variously morphological information by analysis of normal or abnormal chromosomes and it also has the advantage of being able to consult with user on chromosome analysis and diagnosis.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.290-294
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• 1997

Chromosomes, as the genetic vehicles, provide the basic material for a large proportion of genetic investigations. The human chromosome analysis is widely used to diagnose genetic disease and various congenital anomalies. Many researches on automated chromosome karyotype analysis has been carried out, some of which produced commercial systems. However, there still remains much room for improving the accuracy of chromosome classification. In this paper, we propose an optimal pattern classifier by neural network to improve the accuracy of chromosome classification. The proposed pattern classifier was built up of two-step multi-layer neural network(TMANN). We are employed three morphological feature parameters ; centromeric index(C.I.), relative length ratio(R.L.), and relative area ratio(R.A.), as input in neural network by preprocessing twenty human chromosome images. The results of our experiments show that our TMANN classifier is much more useful in neural network learning and successful in chromosome classification than the other classification methods.