• Korean Journal of Plant Tissue Culture
• /
• v.27 no.3
• /
• pp.185-189
• /
• 2000

For the micropropagation, node explants of cassava were cultured in liquid MS medium with various concentrations of cytokinins on a rotary shaker (100 rpm) for 2 weeks. The adventitious roots and shoots from the explants were differentiated more efficiently in liquid medium than in solid. But root formation was not inhibited in medium with BAP and kinetin at low concentration (＞0.05 mg 1/sup -1/), while in medium added with BAP and zeatin at high level (＜0.25 mg 1/sup -1/), it was inhibited by callus forming on cut end of the cuttings. However, all of plantlets grown in liquid medium for more than 2 weeks showed symptoms of hyperhydricity. The plantlets grown in liquid medium were transferred into culture bottles filled with fine sand or artificial soil (pitmoss：perlite：vermiculite, 1：1：1 v/v) wetted with half strength of Knop's solution. After transplanted to culture bottles, some of vitriscent leaves were defoliated and new leaves were normally formed from shoot apex. Most of plantlets (＞95%) were hardened-off successfully only in culture bottles with fine sand, and grew into 3-5 cm seedlings possessing 4-6 nodes after 4 weeks. Thus, the mass propagation of cassava on medium containing cytokinin could be established based on the suspension culture using node explants.

• Korean Journal of Head & Neck Oncology
• /
• v.19 no.1
• /
• pp.9-15
• /
• 2003

Purpose: To introduce our early experience with intensity-modulated radiotherapy (IMRT) in the treatment of nasopharyngeal carcinoma. Methods and Materials: Eight patients who underwent IMRT for no disseminated nasopharyngeal carcinoma at the Asan Medical Center between September 2001 and November 2002 were evaluate by prospective analysis. According to the 1997 American Joint Committee on Cancer staging classification, 5 had Stage III, and 3 had Stage IVB disease. The IMRT plans were designed to be delivered as a 'Simultaneous Modulated Accelerated Radiation Therapy' (SMART) using the 'step and shoot' technique with a MLC (multileaf collimator). Daily fractions of 2.2-2.5Gy and 1.9-2Gy were prescribed and delivered to the GTV and CTV and clinically negative neck node, respectively. The prescribed dose was 70A-79.0Gy to the gross tumor volume (GTV), 60Gy to the clinical target volume (CTV) and metastatic nodal station, and 46Gy to the clinically negative neck. All patients also received weekly cisplatin during radiotherapy. Acute and late normal tissue effects were graded according to the Radiation Therapy Oncology Group (RTOG) radiation morbidity scoring criteria. Results: Follow-up period was ranging from 5 to 18 months. All patients showed complete response and loco-regional control rate was 100% but one patient died of malnutrition due to treatment related toxicity. There were no Grade 3 or 4 xerostomia and all patients had experienced improvement of salivary gland function. Conclusion: 'Simultaneous Modulated Accelerated Radiation Therapy' (SMART) boost intensity-modulated radiotherapy technique allows parotid sparing as evidenced both clinically and by dosimetry. Initial tumor response and loco-regional control was promising. It is clinically feasible. A larger population of patients and a long-term follow-up are needed to evaluate ultimate tumor control and late toxicity.

• Journal of Yeungnam Medical Science
• /
• v.12 no.1
• /
• pp.1-9
• /
• 1995

A monoclonal antibody to PCNA, which can be used on routinely processed tissue, was applied to 25 cases of gastric adenomas and 64 cases of gastric adenocarcinomas in order to diffentiate adenoma and adenocarcinoma and also to evaluate the prognostic value in adenocarcinoma. The results were summerized as follows: The peNA labelling index was $29.14{\pm}12.77%$ in control, $44.09{\pm}17.11%$ in adenoma and $80.15{\pm}10.69$ in adenocarcinoma, resulting in significant increase in adenocarcinoma compared to adenoma. In adenocarcinoma, no significant correlation was observed between PCNA labelling index and histologic grade, and there was increased tendency of PCNA labelling index in proportion to depth of invasion without statistical significance. The PCNA index was significantly increased in advanced adenocarcinoma compared to early gastric carcinoma, and also in positive nodal metastasis group than in negative group. From above results, the PCNA stain will be able to provide a helpful method for the differential diagnosis between gastric adenoma and adenocarcinoma, and could be a useful prognostic factor in adenocarcinoma if other factors are considered together.

• Korean Journal of Bronchoesophagology
• /
• v.3 no.1
• /
• pp.70-78
• /
• 1997

The development of preneoplastic and neoplastic squamous cell proliferations of body sites such as the skin, female lower genital tract, and larynx is strongly associated with specific types of human papillomaviruses (HPV). Antitumor $CD^{8+}$ cells recognize peptide antigens presented on the surface of tumor cells by major histocompatibility complex (MHC) class I molecules. The MHC class I molecule is a heterodimer composed of an integral membrane glycoprotein designated the alpha chain and a noncovalently associated, soluble protein called beta-2-microglobulin( $\beta$ -2-m). Loss of $\beta$-2-m generally eliminates antigen recognition by antitumor $CD^{8+}$ T cells. We evaluated the expression of $\beta$-2-m as a potential means of tumor escape from immune recognition and the presence of HPV DNA as a cause of laryngeal squamous cell carcinomas (SCCs). Laryngeal SCCs (n=39) were analyzed for MHC class I expression by immunohistochemistry and for presence of HPV by in situ hybridization technique. The results were as follows : 1) HPV DNA was detected in 10 (25.64%) out of 39 cases in laryngeal squamous cell carcinomas. 2) MHC class I down-regulation (heterogenous and negative expression) in HPV positive lesions was higher than HPV negative lesions. 3) The expression of MHC class I was related to cellular differentiation regardless of T-stage and nodal involvement. In conclusion, HPV was thought to be the etiological factor of SCC of larynx, and we found that the down-regulation of MHC class I was a common phenomenon In laryngeal SCC and may provide a way for tumor cells to escape from immune surveillance.

• Korean Journal of Breeding Science
• /
• v.40 no.1
• /
• pp.39-47
• /
• 2008

The 1,874 rice lines were selected from 3,000 Ds insertional mutant pool by Basta herbicide treatment and were surveyed for trait variation and molecular characteristics of genes knocked out by Ds insertion. Compared with "Donjin", an original japonica cultivar used for transformation, Ds insertion mutant pool showed large variation in major agronomic traits including tiller, panicle, and heading etc. Southern blot analysis demonstrated that these lines on the average had two Ds copies in Donjin genome, resulting in 38.4% of one copy, 32.5% of two copies, 16.7% of three copies, and 11.3% of over four copies. GUS analysis showed that 3.9% of lines (73/1,860) had tissue-specific expression in leaves, nodal parts, floral organs such as stigma and pollen, and roots. Data set obtained from agricultural trait variation and molecular characteristics for individual Ds insertional lines would provide researchers with more information for understanding the function of unknown rice genes controlling economically important traits.

• Journal of Korea Port Economic Association
• /
• v.35 no.2
• /
• pp.21-36
• /
• 2019

To ensure that Korea continues to grow, past governments have been consistent in following a policy of advancing into Russia, Mongolia, and Eurasia. The northern economy can expect to achieve synergistic growth because its economic structure complements that of Korea, which has high energy demand and industrial development. There is also an opportunity to accelerate the growth of the China-Russia-Mongolia economic corridor, which is based on Russia's Look East Policy, China's One Belt One Road, and the Mongolian Steppe Road initiative. The Korean government is pursuing a New Northern Policy to achieve the goal of economic cooperation and peace building with other nations, including North Korea; this policy succeeds the Northern Policy pursued by the previous government. As international economic cooperation requires transportation infrastructure, the demand for shipping, which offers more advantages than road and rail transportation, will increase; thus, it is necessary to prepare for it. Korea's port cities, which have a port that serves as the nodal point for maritime transportation, need to prepare for the New Northern Policy. In this paper, the long-term development of Seosan-Daesan port in the was planned and the North Korea's opening-op plan was considered in accordance with the New Northern Policy. Because international cooperation between the government and the provincial cities is required, cooperation with the Port Authority is needed, along with the proactive attitude of Seosan City, Chungcheongnam-do. The Seosan-Daesan port, which is the center of the liquid energy cargo center, can become the base of the New Northern Policy Region; further, the port can be an opportunity to establish its position as a peaceful economic hub on the west coast of Korea.

• Journal of Korean Society of Forest Science
• /
• v.108 no.2
• /
• pp.216-223
• /
• 2019

This study was conducted to measure the changes in the geological and soil properties following slow-moving landslide events in Yangbuk-myun and Gyungju-si, Gyeongsangbuk-do, South Korea. The geological characteristics of the study site comprised black shale in the Gyeongsang nodal group formed in the Cretaceous period and quartz feldspar carcinoma in the east side with conglomerate in the Yeonil group formed in the Quaternary period. The study site exhibited the geologic characteristics of a slow-moving landslide with severely weathered rocks. The maximum collapsing depth of the slow-moving landslide was 12.0 m with colluvial deposits. The strike and joint aspects in the slope areas of the slow-moving landslides were $N46^{\circ}E$ in lower slope and $N62^{\circ}E$ in upper slope, respectively. Soil hardness of ${\leq}20cm$ deep was not measured because of the completely disturbed soil resulting from soil creeping. Soil from 25 to 90 cm deep was 1.4-4.7 times softer in the slow-moving landslide areas than in the undisturbed or natural forests. Soil bulk density was $1.24-1.29g/cm^3$ in land creep areas. Soil bulk in both areas was 1.6 times denser than that in the natural forest. The soil pore space was 51.5-53.3% in the land creep areas. The values are 1.3-1.4 times lower than those within the natural forest. Black shale areas showed the lowest coefficient of permeability (8.75 E-06 cm/s) and mesopore ratio (pF 2.7: 9.8%) compared with those resulting from other study areas.

• Journal of the Economic Geographical Society of Korea
• /
• v.22 no.3
• /
• pp.258-273
• /
• 2019

Bilbao, Spain, made a mark as a example of the regional revitalization by culture and tourism. Korean Government have a perspective that culture and tourism could be an alternative to the regional crisis of manufacturing in 2018. The main purpose of this study is to analyze the locational specificity and the revival strategies for the regional development of Bilbao in a structural context. This could provide implications to the regional crisis of Korea. The main results are summarized as follows. Firstly, the local government of Bilbao has taken an active role, using not only its political and financial autonomy but also its locational advantage as an important nodal region of transnational trade networks in Europe. Secondly, Bilbao was able to sustain its regional revitalization initiatives for a long period by facilitating public-private partnership system. Finally, despite the effectiveness of the mega project and place marketing, low job security and the polarization of the service sector have emerged as a problem at the same time. Still, the deindustrialization of Bilbao could be possible due to the various services including knowledge-based services and financial services as well as culture and tourism.

• Journal of Chest Surgery
• /
• v.55 no.1
• /
• pp.49-54
• /
• 2022

Background: We compared the safety and effectiveness of robotic anatomical resection and video-assisted thoracoscopic surgery (VATS). Methods: A retrospective analysis was conducted of the records of 4,283 patients, in whom an attempt was made to perform minimally invasive anatomical resection for lung cancer at Seoul National University Hospital from January 2011 to July 2020. Of these patients, 138 underwent robotic surgery and 4,145 underwent VATS. Perioperative outcomes were compared after propensity score matching including age, sex, height, weight, pulmonary function, smoking status, performance status, comorbidities, type of resection, combined bronchoplasty/angioplasty, tumor size, clinical T/N category, histology, and neoadjuvant treatment. Results: In total, 137 well-balanced pairs were obtained. There were no cases of 30-day mortality in the entire cohort. Conversion to thoracotomy was required more frequently in the VATS group (VATS 6.6% vs. robotic 0.7%, p=0.008). The complete resection rate (VATS 97.8% vs. robotic 98.5%, p=1.000) and postoperative complication rate (VATS 17.5% vs. robotic 19.0%, p=0.874) were not significantly different between the 2 groups. The robotic group showed a slightly shorter hospital stay (VATS 5.8±3.9 days vs. robotic 5.0±3.6 days, p=0.052). N2 nodal upstaging (cN0/pN2) was more common in the robotic group than the VATS group, but without statistical significance (VATS 4% vs. robotic 12%, p=0.077). Conclusion: Robotic anatomical resection in lung cancer showed comparable early outcomes when compared to VATS. In particular, robotic resection presented a lower conversion-to-thoracotomy rate. Furthermore, a robotic approach might improve lymph node harvesting in the N2 station.

• Journal of Gastric Cancer
• /
• v.22 no.2
• /
• pp.120-134
• /
• 2022

Purpose: This study aimed to identify prognostic factors for patients with distant lymph node-involved gastric cancer (GC) using a machine learning algorithm, a method that offers considerable advantages and new prospects for high-dimensional biomedical data exploration. Materials and Methods: This study employed 79 features of clinical pathology, laboratory tests, and therapeutic details from 289 GC patients whose distant lymphadenopathy was presented as the first episode of recurrence or metastasis. Outcomes were measured as any-cause death events and survival months after distant lymph node metastasis. A prediction model was built based on possible outcome predictors using a random survival forest algorithm and confirmed by 5×5 nested cross-validation. The effects of single variables were interpreted using partial dependence plots. A contour plot was used to visually represent survival prediction based on 2 predictive features. Results: The median survival time of patients with GC with distant nodal metastasis was 9.2 months. The optimal model incorporated the prealbumin level and the prothrombin time (PT), and yielded a prediction error of 0.353. The inclusion of other variables resulted in poorer model performance. Patients with higher serum prealbumin levels or shorter PTs had a significantly better prognosis. The predicted one-year survival rate was stratified and illustrated as a contour plot based on the combined effect the prealbumin level and the PT. Conclusions: Machine learning is useful for identifying the important determinants of cancer survival using high-dimensional datasets. The prealbumin level and the PT on distant lymph node metastasis are the 2 most crucial factors in predicting the subsequent survival time of advanced GC.