• Animal cells and systems
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• v.6 no.4
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• pp.301-304
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• 2002

In our previous study, we have shown that Fgf-8 is expressed in the basal layer of the apical epithelial cap (AEC) and in the underlying thin layer of mesenchymal tissue of the regenerating limbs of Mexican axolotl, Amby-stoma mexicanum. Our present RT-PCR data also demonstrate that Fgf-8 transcript is localized both in the mesenchymal and epidermal tissues. To understand the effect of retinoic acid (RA) on the expression of Fgf-8 in the regenerating axolotl limbs, RA was injected intraperitoneally at the dediffer-entiation stage of limb regeneration. The RA treatment caused 8 change in the Fgf-8 expression profile of the regenerating limbs. In RA-treated limbs, duration of Fgf-8 expression was prolonged and a high level of expression was maintained during dedifferentiation and blastema formation stages. These results suggest that Fgf-8 is an important molecule in the process of pattern duplication of regenerating salamander limbs evoked by RA treatment.

• Animal cells and systems
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• v.5 no.2
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• pp.91-99
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• 2001

Vertebrates regenerate tissues in three ways: proliferation of cells that maintain some or all of their differentiated structure and function, redifferentiation of mature cells followed by proliferation and redifferentiation into the same cell type or transdetermination to another cell type, and activation of restricted lineage stem cells, which have the ability to transdetermine to different lineages under the appropriate conditions. The behavior of the cells during regeneration is regulated by growth factors and extracellular matrix molecules. Some non-regenerating tissues are now known to harbor stem cells which, though they form scar tissue in vivo, are capable of producing new tissue-specific cells in vitro, suggesting that the injury environment inhibits latent regenerative capacity. Regenerative medicine seeks to restore tissues via transplantation of stem cell derivatives, implantation of bioartificial tissues, or stimulation of regeneration in vivo. These approaches have been partly successful, but several research issues must be addressed before regenerative medicine becomes a clinical reality.

• Plant Resources
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• v.4 no.1
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• pp.53-58
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• 2001

The effect of carbenicillin on the dedifferentiation and the regeneration efficiency of plant tissues of horseradish(Armoracia rusticana) was evaluated, Inhibition effect for callus initiation was observed when leaf blade, root and petiole segments were grown on MS medium containing 500 mg/L to 2000 mg/L carbenicillin and 0.5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D). The regeneration of horseradish shoots from leaf blade, root and petiole explants were decreased as the addition of carbenicillin increased from 1000 mg/L to 2000 mg/L in MS medium containing 0.5 mg/L of 6-benzylaminopurine (BAP) or kinetin. Especially, 500 mg/L carbenicillin treatment significantly inhibited shoot induction when leaf blade explants were grown on hormone-free MS medium. It was suggested that the toxic effects of combinations of carbenicillin and 2,4-D may be due to high auxin activity levels.

• Korean Journal of Plant Resources
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• v.32 no.3
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• pp.237-243
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• 2019

Soybean is the one of recalcitrant legume species for shoot induction. Shoot regeneration via direct organogenesis was investigated in five soybean cultivars, 'Dawon', 'Pungsan', 'Daewon', 'Taekwang' and 'Chongdoo 1' by using cotyledonary node explants. Out of 5 soybean cultivars, an efficient shoot regeneration condition was developed in the two soybean cultivars, 'Dawon' and 'Pungsan'. When various kinds of plant growth regulators with different concentration were estimated, the optimum medium condition for shoot induction in both soybean cultivars was MS + B5 vitamin supplemented with BA at concentration 2 mg/L. In addition, shoot formation efficiency was increased with 97.09% and 93.88% by the pretreatment of BA onto the explants before in vitro culture in both cultivars. Shoot induction in 'Dawon' cultivar was originated from epidermal tissue and sub-epidermal layers when histological changes were investigated under shoot regeneration after culturing cotyledonary node segments on shoot induction medium for 0 to 21 days. Especially, cell dedifferentiation was observed from parenchyma cells to meristematic cell in 3-day cultured segments.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.173-192
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• 1999

The purpose of this study was to evaluate the effects of bioactive glass and natural coral on the human periodontal ligament fibroblast(HPLF) behaviors during the regeneration process of peridontium. To determine the cellular events occuring in the presence of the particles of bioactive glass and natural coral, HPLF were isolated from healthy premolar teeth extracted for orthodontic treatment. Cells were cultured in ${\alpha}$MEM at 37$^{\circ}C$, 5% $CO_2$, 95% humidity incubator. Bioactive glass and natural coral were powdered, and each particles(<40${\mu}$m) were placed on the cultured cells at the concentration of 0.3mg/ml, and 1,0mg/ml for experimental group. In control group no particles were added. And each group was evaluated by examining the cell morphology under phase-contrast micrograph at 4 day and transmission electron micrograph(TEM) and scanning electron micrograph(SEM) at 14 day, alkaline phosphatase activity at 5 and 9 day, protain synthesis at 4 day, DNA synthesis at 1, 2, 3 and 4 day, cell proliferation at 1, 3, 5,7 and 9 day and the formation of bone nodule at 30 day after culturing all groups in mineralizing supplemented mediun, No significant changes in cell morphology by adding these two matirials were found under phase contrast microscopy and TEM. HPLF phagocytocized each particles suggesting that HPLF is involved in the process of resorbing each particles and that bioactive glass were more biocompatible than natural coral. The ALPase activity of bioactive glass 0.3 mg/ml was similar with control groups and all the rests of control groups were significantly low(P<0.01) indicating a transient dedifferentiation of HPLF in the presence of bioactive glass and natural coral particles. There were no significant differences of protein synthesis between all groups. The DNA synthesis in experimental groups were significantly lower than control groups at 1, 2 and 3 day (P<0.01) but became similar to control groups at 4 day. Between control groups, the DNA synthesis in bioactive glass O.3mglml group was significantly higher than other groups(P<0.01). Cell proliferation in natural coral 1.0mg/ml and bioactive glass 1.0mglml groups were significantly lower than control group at 3 day(P<0.05) and there were no differences at 5, 7, 9 day. There were more bone nodule formation in experimental groups than in control groups. In conclusion, these results indicated that bioactive glass and natural coral have some effects of a transient dedifferentiation on HPLF and regeneration of periodontal tissues, however any significant cytotoxic effect on HPLF by these two particles were not found.

• Journal of Yeungnam Medical Science
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• v.13 no.1
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• pp.146-151
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• 1996

Majority of hepatocellular carcinoma is evolved from a well differentiated cancerous condition such as hyperplastic lesions eg. adenomatous hyperplasia in cirrhotic liver or de no vo carcinogenesis and prolifenation along with dedifferentiation. Adenomatous hyperplasia is may be seen in severe acute hepatic injury, like submassive hepatic necrosis, or in chronic liver diseases, particularly liver cirrhosis and it has recently attracted much interest from both clinicians and pathologists because it is regarded as a precursor lesion of hepatocellular carcinoma. Hepatic adenomatous hyperplasia resembling focal nodular hyperplasia might have developed from localized vascular changes associated with chronic liver disease, pre-existing arterial malformation and early stage of angiogenesis in hepatocarcinogenesis. We present a patient who developed hepatocellular carcinoma after hepatic artery ligation.

• Journal of Plant Biotechnology
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• v.6 no.3
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• pp.157-163
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• 2004

An efficient system for the regeneration of adventitious shoots from in vitro cultured leaf sections of Lycium chinense Miller was developed and silent somaclones from the regenerants detected with RAPD method. Among the eight media tested (B5, SH, N&N, 1/2MS, MS, 3/2MS, GD and WPM), and four cytokinins (BA, kinetin, 2ip and zeatin) with different concentrations (1, 5, 10, 20, 30 and 40 $\mu{M}$), 1/2 MS medium supplemented with 20 and 30 $\mu{M}$ zeatin showed the best regeneration frequency (100% and 93.7%) and higher average number of shoots (9.0 and 9.4). All regenerants easily elongated after subculturing on 1/4MS without growth stimulants and produced spontaneous adventitious roots from their basal parts. With phenotypically normal 40 regenerants, RAPD analysis with 15 different random primers was performed to examine the cryptic somaclonal variants. No substantial differences in banding patterns were found in the amplified polymorphic DNAs implying no DNA changes during dedifferentiation into adventitious shoots. However, one (OPF-4) of the 15 primers detected silent somaclonal variation in one regenerant in which two different polymorphic bands did not appear when compared with the rest regenerants. The results indicate that regenerantion via intervening callus phase can be used to establish true-to-type planting stocks for homogeneous population.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.428-431
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• 2015

Epithelial-myoepithelial carcinoma (EMC) of lung is a minor subset of salivary type carcinoma of lung of known low grade malignancy. Histologically, two-cell components forming duct-like structure with inner epithelial cell layer and outer myoepithelial cell layer are characteristics of EMC. In salivary gland, dedifferentiation of conventional low grade malignancy has been reported and is thought to be related with poor prognosis. However, precise histomorphology and prognostic factors of pulmonary EMC have not been clarified due to its rarity. Herein, we reported a rare case of EMC presented as endobronchial mass in a 53-year old woman, which showed predominant solid lobular growth pattern and lymph node metastases.

• Journal of Pharmacopuncture
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• v.22 no.2
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• pp.55-67
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• 2019

The incidences of cancer are continuously increasing worldwide, affecting life of millions of people. Several factors associated with the internal and external environment are responsible for this deadly disease. The key internal determinants like abnormal hormonal regulation, genetic mutations and external determinants such as lifestyle and occupational factors enhances onset of cancer. From the ancient time, plants were remained as the most trusted source of medicine for the treatment of diverse disease conditions. Extensive studies have been performed for the discovery of effective anticancer agent from the plant and still it is going on. Pentacyclic triterpenoids are biologically active phytochemicals having a different range of activities such as anti-inflammatory, hepatoprotective, anti-hypertensive, antiulcerogenic and anti-tumor. These compounds generally contain ursane, oleanane, lupane and friedelane as a chief skeleton of pentacyclic triterpenoids which are generally present in higher plants. Isoprene unit, phytochemical, with good antitumor/anticancer activity is required for the biosynthesis of pentacyclic triterpenoids. Mechanisms such as cytotoxicity, DNA polymerase inhibition, regulation of apoptosis, change in signal transductions, interfere with angiogenesis and dedifferentiation, antiproliferative activity and metastasis inhibition are might be responsible for their anticancer effect. Present review spotlights diverse targets, mechanisms and pathways of pentacyclic triterpenoids responsible for anticancer effect.

• Genomics & Informatics
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• v.19 no.1
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• pp.2.1-2.10
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• 2021

BRAF inhibitors (e.g., vemurafenib) are widely used to treat metastatic melanoma with the BRAF V600E mutation. The initial response is often dramatic, but treatment resistance leads to disease progression in the majority of cases. Although secondary mutations in the mitogen-activated protein kinase signaling pathway are known to be responsible for this phenomenon, the molecular mechanisms governing acquired resistance are not known in more than half of patients. Here we report a genome- and transcriptome-wide study investigating the molecular mechanisms of acquired resistance to BRAF inhibitors. A microfluidic chip with a concentration gradient of vemurafenib was utilized to rapidly obtain therapy-resistant clones from two melanoma cell lines with the BRAF V600E mutation (A375 and SK-MEL-28). Exome and transcriptome data were produced from 13 resistant clones and analyzed to identify secondary mutations and gene expression changes. Various mechanisms, including phenotype switching and metabolic reprogramming, have been determined to contribute to resistance development differently for each clone. The roles of microphthalmia-associated transcription factor, the master transcription factor in melanocyte differentiation/dedifferentiation, were highlighted in terms of phenotype switching. Our study provides an omics-based comprehensive overview of the molecular mechanisms governing acquired resistance to BRAF inhibitor therapy.