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Marine Bacteriological Quality and Dynamics in Tongyeong Coastal Area, Gyung-nam, Korea (통영연근해역의 해양세균학적 수질 및 동태에 관한 연구)

  • 최종덕
    • Journal of Food Hygiene and Safety
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    • v.14 no.4
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    • pp.372-379
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    • 1999
  • A bacteriological study of sea water and oyster in Tongyeong coastal area was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria fur the designated area of shellfish cultivation. The Samples were collected at 5 zone, 34 sampling stations(Fig. 1) established once a month from September 1997 to August 1998. During the study period, temperature ranged from 6.9 to 23.6$^{\circ}C$, transparency ranged from 2.6 to 6.2 m, chemical oxygen demand ranged from 1.35 to 1.82 mg/ι, dissolved oxy-gen ranged from 5.0 to 9.9 mg/ι, dissolved nitrogen ranged from 1.60 to 8.17 $\mu\textrm{g}$-at/ι, phosphate ranged from 0.14 to 1.21 $\mu\textrm{g}$-at/ι, Chlorophyll-a ranged from 2.03 to 69.9 mg/㎥, respectively. The coliform group and fecal coliform MPN's of sea water were ranged from <3.0~1,600 and <3.0~540, respectively. The coliform group and fecal coliform MPN's of oysters were ranged from <18~16,000 and <18~2,200, respectively. The viable cell counts in oyster ranged from $1.5\times$10$^2$to 8.2$\times$10$^3$. The coliform stoup, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. 437 strains that were obtained from Tongyeoung coastal area seawater samples represented E. coli group 47.5%, C. freundii group 14.8%, K. aerogenes 10.9%, unknown 26.8%, respectively. During the study period, infectious bacteria such as Vibrio ohoEerae, Salmonella sp. and Shigella sp. were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnificus were 12~21% in summer months.

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Bacteriological Study of Sea Water and Oyster in Charan Bay, Korea (자란만의 해수 및 굴의 세균학적 연구)

  • CHOI Jong-Duck;JEONG Woo-geon;KIM Poong-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.3
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    • pp.429-436
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    • 1998
  • A bacteriological study of sea water and oyster in Charan Bay was conducted to evaluate sanitary conditions of the bay and compliance of waters with the recommended bacteriological criteria for the designated area of shellfish cultivation, The Samples were collected at 23 sampling stations(Fig. 1 and Fig. 2) estaslished once a month from January 1997 to December 1997, During the study period, temperature ranged from 4.7 to $25.6^{\circ}C$, transparency ranged from 3.3 to 6.2m chemical oxygen demand ranged from 1.67 to 2.18 mg/$\ell$, dissolved oxygen demand ranged from 5.4 to 10.0 mg/$\ell$ dissolved nitrogen ranged from 1.65 to 7.88 $\mu$g-at/$\ell$, phosphate ranged from 0.15 to 1.16 $\mu$g-at/$\ell$, Chlorophylla-a ranged from 0.95 to 12.69mg/$\ell$. The coliform group and fecal coliform MPN's of sea water were ranged from <1.8$\~$l,600 and <1.8$\~$540, respectively. The coliform group and fecal coliform MPN's of oysters were ranged from <18$\~$16,000 and <18$\~$1,400, respectively. The viable cell counts in oyster ranged from $1.5\times10^2$ to $7.5\times10^3$. The bacteriological criteria of sea water in shellfish growing area should be less than 70 per 100 ml of sea water for median value of coliform MPN, and below $10\%$ of the samples which contain over than 230 for coliform MPN or over than 43 for fecal coliform MPN. The sea water from 432 samples were complied water coliform criteria recommended for designated shellfish growing area. The coliform group, fecal coliform, classification of coliform group with IMViC reactions and pathogenic vibrios were analyzed. During the study period, infectious bacteria such as Vibrio cholerae, Salmonella sp, and Shigella sp, were not detected from the samples, but detection ratios of Vibrio parahaemolyticus and Vibrio vulnifirus were $7\~17\%$ in summer months.

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The Study on the Buttons (centering around 19th-20th Centuries) (단추에 관한 연구 -19, 20세기를 중심으로-)

  • 이영란
    • Journal of the Korean Society of Costume
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    • v.22
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    • pp.263-276
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    • 1994
  • The achievement of notable social reoforms attained during the period of 19th and 20th centuries needlessly speaking remodelded the social environmental into several different patterns such as :1) high industrialization 2) propensity to consume 3) up graded overall social stands. Accordingly the industrial world of the but-tons too established the mess production syhstem by breaking from convention of hand-craft work of 17th century. The raw materials used in the production line on buttons during the 20th century are almost all-kind of materials one can possibly named including cheap plastic which enabled production lines to produce cheaper but higher productivities of the buttons being produced, The design (incused design) used in the 19-20h centuries are : men landscape, sports features, birds, livestocks, bugs, or geomatric features, tec, 1, The classification o f the buttons by materials Techniques shapes colors marking (Incused design) used in the productionof buttons in the England United States of America Laska Italy france Denmark Japan and India are categolizzed as : natural raw materials and syntetical resines. 1) Of the natural raw materials used are : Matal Enamel Iodine Agate, Coral, Green jade(Jasper) Granite, Wood, Ivory, Horn and bone etc. 2) The sythetical resin used in the button in-dustries are : Artificial jewell glass Acrylic material Styroform Celluloid and Nylon etc. 2. The thecnique quoted in producing buttons are hand craft work inlay work precision casting press mosic dye etching, processing, engraving and embossed carving etc. 3. The major designs used in the buttons in -dustries are : Round shape however elliptical column angular and edge shape often used. 4. The colors used are : The multi-colors were highly used than mono-colored materials such as : Adjoining Color and Contrast Color. The highest consideration to be considered in choosing the colors for the buttons are harmonization and matching factor with the garment or dresses to be wore. 5. The major design(incused design) on the buttons are embodiment and the design were also used in order of abstractive-combination abstractive with has offers much surprising. The button industries during the 19th and 20th centuries were not only the determination factors those can judge the value of self-pride of Nation and which were far beyond the in-dustrial arts in those days but also highly refelected and influenced by cultural sense ideology and self-pride of the Nation of those period. The followings are details of the role of the buttons categolized in the order of functional ornamental and symbolical aspects : 1. The functional role : The functional role of the buttons were simply designed for dress how-ever the buttons beyond from this role of function now a days. 2. The ornamental role : The ornamental role of he button beyond from this role of the button were effectuated by : 1) shape materials colors 2) technique locations size and design (incused design) 3) The ramaterials used for buttons shall not be over looked because it is highly depends on the taste sense and combination of harmony with the garment to be wore. 4) The color of the buttons are made well contrasted with the color of garments just as in the case of other artistical area such as matchs with the color of garment of contrast with brigtness of colors contrasted as complementary color and so and so. 5) The technique being adoped are: precision casting press handcraft inlay work etching mosic etc,. Since the buttons are no longer a simple catching devise used to fasten together the different part of the dress but now it has formed own and occupied the independent role in the garment or dresses location can be de-termined and varying depending on the ideas of designers. The size of the buttons has no specific limits, However the variation has widely dependined on the entire circumperence rhythm contrast harmonization of the garments. 3. The symbolical role : Since the button is no longer a just a simple devise for catching and fastening device used fastening together the different part of the garments but now were built a independent area as major part of the Garment and well reflected all kinds of occupations political background cultural as-pect etc. on the buttons. The design of buttons in the western circles are more simplified but they are polished looks and their techniques of manufacturing are comination of both machanis and handcraft. The colors used in the buttons are pretty well harmonized with garment(dress). Almost all kind of materials can be used in the but-tons however materials used in the buttons are : Bone of livestocks ivory, turtle shell are no longer used because the prevention of cruely of animal. On the contraly the level of buttons indus-try of Korea is far to reach and catch up with the level of western circles. It is highly suggested therefore the but-tons industrial field of Republic of Korea shall place and encouragement in producing beter industrial environment of the buttons based on the traditional and cultural aspect of republic of Korea to produce both manufacturing of qulified and best designed and colored buttons.

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A Stduy on the Microflora of the Han River -Taxonomy of Phytoplankton for the South Han River and Estimation of Water Pollution Levels on the Central Area of the Han River- (한강의 Microflora에 관한 연구 (제6보) -남한강의 식물성플랑크톤에 대한 분류와 한강중심수역의 수질오탁판정-)

  • 정영호
    • Journal of Plant Biology
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    • v.15 no.s
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    • pp.1-32
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    • 1972
  • In order to utilize for the prevention and preservation of the Han River from the environmental pollution the present studies were carried out to clarify the microflora and estimation of the water pollution levels of the Han River. In addition to the above regional and seasonal fluctuation of the phytoplankton was also examined. Samples of phytoplankton were collected from 6 stations in the South Han River during the period from December, 1971 to October, 1972. The results obtained during the present studies are as follows: 1. The phytoplankton samples collected from 6 stations, Yeoju, Hajapo-ri, Yangpyeong, Daruraegi, Giduwon and Paldang were identified and classified by Engler's classification system(1954). It resulted in 2 phylum, 2 classes, 7 orders, 10 families, 29 genera, 137 species, 1 sub-species, 49 varieties, 6 forma and 2 variety-forma. The total numbers of phytoplankton identified were 195 species, of which 7 families, 27 species, 26 varieties, 4 forma and 2 variety-forma are new to Korea, that of 54 species are first described in Korea. 2. In lower area of the Han River it is found 53 species from Paldang and in middle area it is found 114 species from Giduwon, 95 species from Daruraegi, 66 species from Yangpyeong, 71 species from Hajapori and 81 species from Yeoju. In standpoint of seasonal fluctuation of phytoplankton, the total numbers of the plankton is more abundant in summer than in winter season and it shows bimodal pattern. 3. As compared with previous data which obtained from 30 stations covering estuary to upper area, both South and North Han River, during the period from 1965-1972 it is shown that 10 species of the South Han River and 11 species of the North Han River are found throughout all seasons. Among the above species two are common in both area. In the other hand it is found that 9 species in spring season and 6 species in fall season in the South Han River and 10 species in spring, 23 species in summer, 4 species in fall and 15 species in winter season in the North Han River shows their seasonal fluctuation in this area. Among the seasonal occurrence of phytoplankton 10 species were consider to be indicator for the estimation of biological water pollution levels. 4. According to Fjerdingstad's water pollution level system (1963) the total numbers of 1, 230 species which have been collected from the Han River since 1965 includes 27 species of phytoplankton as indicator; 3 species of blue-green algae, 20 species of diatom, and 4 species of green-algae. 5. With 27 indicator species new estimation of water pollution level system was arranged for water pollution in the Han River. 6. The lower part of the central area of the Han River indicates mesosaprobic. In central area of the Han River shows mesosaprobic and oligosaprobic, but predominant in mesosaporobic. And it is indicated that mesosaprobic, oligosaprobic, and polysaprobic factors mixed up in the North Han River. Compare with their water pollution level in the South and North Han River, with author's new system, it is estimated that North Han River is more polluted than South Han River. 7. The reason why North Han River is more polluted suggested that the selfpurification action was limited by their circulation speed. The rapid speed of water in the North Han River is mainly caused by their topography and water-drainage from waterpower plant. In conclusion the central area of the Han River consist of mesosaprobe zone, as a part with oligosaprobe zone. But the presence of polysaprobe zone in the North Han River gives us many problems in future for the nationa development programme and natural conservation in this area.

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Treatment of Squamous Cell Carcinoma in Extremity & Trunk (사지와 체부에 발생한 편평상피 세포암의 치료)

  • Shin, Duk-Seop;Kim, Beom-Jung
    • The Journal of the Korean bone and joint tumor society
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    • v.18 no.1
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    • pp.7-13
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    • 2012
  • Purpose: The purpose of this study is to compare general survival rate and survival rate according to expectable prognostic factors by analyzing the result of treating a patient of squamous cell carcinoma. Materials and Methods: From Mar. 1999 to Feb. 2011, 151 patients were pathologically confirmed as squamous cell carcinoma of limbs and body in our hospital, and among those patients, 51 patients underwent the surgical treatment. This study included 41 patients who underwent the surgical treatment and were followed-up for more than 12 months. The mean age of population was 64.4 years. 31 males and 10 females were included. Wide excision with following skin grafts or flaps for reconstruction (29 cases) was mostly performed, but amputation (12 cases) was also performed for cases with extremities where resection margin was difficult to obtain and cases with neural or vascular invasion. 8 patients underwent chemotherapy or radiotherapy after resection, and 33 underwent the operation only. Stages were classified by AJCC Classification, survival rate was calculated by Kaplan-Meier method and survival rate of groups was compared by Log-rank test. For the expectable prognostic factors related to survival rate, location of primary lesion, cause of disease, pathologic grade, staging, surgical method, additional anticancer therapy were examined and each survival rate was compared. Results: The average follow-up period was 65.2 (12-132) months. Thirty patients survived out of 41 patients till last follow up. The overall survival rate in 5 years was 77%. Three cases (7.3%) had local recurrence, and 7 cases (17.0%) had metastasis. The average period of recurrence from operation was 27 (18-43) months. Possible prognostic factors such as location of primary lesion, cause of disease, pathologic grade, staging, additional anticancer therapy showed no significant difference in survival rates. However, patients with amputation showed significantly lower survival rate than those with wide excision. Conclusion: In analysis the results of treating 41 cases of squamous cell carcinoma, the overall 5-year survival rate was 77%. And, among the several prognostic factors, only the surgical method was significant statistically.

Influences of Chinese Cabbage Growth and Soil Salinity to Alternative Irrigation Waters (대체관개 용수에 의한 배추생육 및 토양 염류도에 미치는 영향)

  • Shin, Joung-Du;Park, Sang-Won;Kim, Won-Il;Lee, Jong-Sik;Yun, Sun-Gang;Eom, Ki-Cheol
    • Korean Journal of Soil Science and Fertilizer
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    • v.40 no.1
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    • pp.25-30
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    • 2007
  • Objective of this experiment was to investigate the growth effects of Chinese cabbage and soil salinity to alternative irrigation waters for drought periods. The treatments were consisted of the discharge water from industrial wastewater treatment plant (DIWT), the discharge water from municipal wastewater treatment plant (DMWT) and ground water as the control. For the chemical compositions of alternative water, it appeared that concentrations of the $Ni^+$ and SAR values in DIWT were over the reuse criteria of other countries for irrigation, but CODcr concentration in DMWT was higher than the reuse criteria for agricultural irrigation. According to classification of water by $EC_i$ value, DIWT and DMWT are ranged from 0.7 to $2.0dS\;m^{-1}$, slight salinity. Average harvest indexes were 0.64 for DIWT and 0.63 for DMWT as compared to 0.61 of the control regardless of irrigation periods. SAR value in soil was increased with prolonging the irrigation periods at head forming stage, but not much difference except for 30 days of irrigation period at harvesting time for DIWT. However, it was not much difference along with irrigation periods through the growth stages for DMWT as compared with the groundwater. At harvesting time, average $EC_e$ for the soil irrigated with alternative agricultural waters was $0.017dS\;m^{-1}$ for its DIMT and $0.036dS\;m^{-1}$ for its DMWT as compared to $0.013dS\;m^{-1}$ of its groundwater as the control. For $NH_4-N$ concentrations, it observed that there were no differences among the treatments with different irrigation periods at head forming stage in soil after irrigation. Also, $NO_3-N$ concentration in soil was increased up to 20 days after irrigation, and then decreased at 30 days after irrigation with DMWT at head forming stage. The $Ni^+$ concentration in upper layer soil (0-15 cm) irrigated with DIWT was increased with prolonging the irrigation period at head forming stage, but it was dramatically decreased and almost constant in all the treatments at harvesting time. Therefore, it might be concluded that there was potentially safe to irrigate the discharge water from municipal wastewater treatment plant for 20 days after transplanting to drought periods with cultivating the Chinese cabbage.

A Study on History and Archetype Technology of Goli-su in Korea (한국 고리수의 역사와 원형기술의 복원 연구)

  • Kim, Young-ran
    • Korean Journal of Heritage: History & Science
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    • v.46 no.2
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    • pp.4-25
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    • 2013
  • Goli-su is the innovative special kind of the embroidery technique, which combines twining and interlacing skill with metal technology and makes the loops woven to each other with a strand. The loops floating on the space of the ground look like floating veins of sculpture and give people the feeling of the openwork. This kind of characteristic has some similarities with the lacework craft of Western Europe in texture and technique style, but it has its own features different from that of Western Europe. It mainly represents the splendid gloss with metallic materials in the Embroidered cloth, such as gold foil or wire. In the 10th century, early days of Goryo, we can see the basic Goli-su structure form of its initial period in the boy motif embroidery purse unearthed from the first level of Octagonal Nine-storied Pagoda of Woljeong-sa. In the Middle period of Joseon, there are several pieces of Goli-su embroidered relic called "Battle Flag of Goryo", which was taken by the Japanese in 1592 and is now in the Japanese temple. This piece is now converted into altar-table covers. In 18~19th century, two pairs of embroidered pillows in Joseon palace were kept intact, whose time and source are very accurate. The frame of the pillows was embroidered with Goli-su veins, and some gold foil papers were inserted into the inside. The triangle motif with silk was embroidered on the pillow. The stitch in the Needle-Looped embroidery is divided into three kinds according to comprehensive classification: 1. Goli-su ; 2. Goli-Kamgi-su ; 3. Goli-Saegim-su. From the 10th century newly establishing stage to the 13th century, Goli-su has appeared variational stitches and employed 2~3 dimensional color schemes gradually. According to the research of this thesis, we can still see this stitch in the embroidery pillow, which proves that Goli-suwas still kept in Korea in the 19th century. And in terms of the research achievement of this thesis, Archetype technology of Goli-su was restored. Han Sang-soo, Important Intangible Cultural Heritage No. 80 and Master of Embroidery already recreated the Korean relics of Goli-su in Joseon Dynasty. The Needle-Looped embriodery is the overall technological result of ancestral outstanding Metal craft, Twining and Interlacing craft, and Embroidery art. We should inherit, create, and seek the new direction in modern multi-dimensional and international industry societyon the basis of these research results. We can inherit the long history of embroidering, weaving, fiber processing, and expand the applications of other craft industries, and develop new advanced additional values of new dress material, fashion technology, ornament craft and artistic design. Thus, other crafts assist each other and broaden the expressive field to pursue more diversified formative beauty and beautify our life abundantly together.

Dual Plate Fixation for Periprosthetic Femur Fracture after Total Knee Arthroplasty (슬관절 전치환술 후 발생한 대퇴골 삽입물 주위 골절의 이중 금속판 고정술)

  • Kim, Dong Hwi;Cha, Dong Hyuk;Ko, Kang Yeol
    • Journal of the Korean Orthopaedic Association
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    • v.56 no.1
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    • pp.26-33
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    • 2021
  • Purpose: This study evaluated the results of dual plate fixation for periprosthetic femur fracture after total knee arthroplasty (TKA). Materials and Methods: From October 2007 to February 2013, 23 cases of periprosthetic femur fracture after TKA were treated at the author's hospital. There were 13 cases of fixation using a medial and lateral dual plate when the stability of the fracture site could not be achieved by one side fixation with a follow-up of more than one year. The cases included no loosening of the femoral component in fractures that were categorized as Lewis-Rorabeck classification II and supracondylar comminuted fractures and elongation of the fracture line to the lateral epicondyle of the femur or stem in the medullary canal. The mean age was 72 years (65-82 years), and 11 cases were female. Three cases had a stem due to revision. The mean bone marrow density was -3.2 (-1.7 to -4.4), and the mean period from primary TKA to periprosthetic fractures was 28 months (1-108 months). The mean follow-up period was 23 months (12-65 months). The medial fracture site was first exposed via the subvastus approach. Second, the supplementary plate was fixed on the lateral side of the fracture using a minimally invasive plate osteosynthesis technique. The average union time, complications, and Hospital for Special Surgery Knee Score (HSS) at the last follow-up were evaluated. Results: The mean union time was 17.4 weeks (7-40 weeks). Two cases showed delayed bone union and nonunion occurred in one case, in whom bone union was achieved three months later after re-fixation using a dual plate with an autogenous bone graft. The mean varusvalgus angulation was 1.67 degrees (-1.2-4.9 degrees), and the mean anterior-posterior angulation was 2.86 degrees (0-4.9 degrees) at the last follow-up. The mean knee range of motion was 90 degrees, and the HSS score was 85 points (70-95 points) at the last follow-up. Conclusion: Dual plate fixation for periprosthetic femur fractures that had not achieved stability by one side plate fixation after TKA showed a good clinical result that allowed early rehabilitation.

An Overview of Surgical Treatment of Thymic Epithelial Tumors in Korea: A Retrospective Multicenter Analysis

  • Lee, Jun Oh;Lee, Geun Dong;Kim, Hyeong Ryul;Kim, Dong Kwan;Park, Seung-Il;Cho, Jong Ho;Kim, Hong Kwan;Choi, Yong Soo;Kim, Jhingook;Shim, Young Mog;Park, Samina;Park, In Kyu;Kang, Chang Hyun;Kim, Young Tae;Park, Seong Yong;Lee, Chang Young;Lee, Jin Gu;Kim, Dae Joon;Paik, Hyo Chae;the Korean Association for Research on the Thymus,
    • Journal of Chest Surgery
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    • v.55 no.2
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    • pp.126-142
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    • 2022
  • Background: Thymic epithelial tumors (TETs) are rare, and information regarding their surgical outcomes and prognostic factors has rapidly changed in the past few decades. We analyzed surgical treatment practices for TETs and outcomes in terms of overall survival (OS) and freedom from recurrence (FFR) during a 13-year period in Korea. Methods: In total, 1,298 patients with surgically resected TETs between 2000 and 2013 were enrolled retrospectively. OS and FFR were calculated using the Kaplan-Meier method and evaluated with the log-rank test. Prognostic factors for OS and FFR were analyzed with multivariable Cox regression. Results: A total of 1,098 patients were diagnosed with thymoma, and 200 patients were diagnosed with thymic carcinoma. Over the study period, the total number of patients with surgically treated TETs and the proportion of patients who underwent minimally invasive thymic surgery (MITS) increased annually. The 5-year and 10-year survival rates of surgically treated TETs were 91.0% and 82.1%, respectively. The 5-year and 10-year recurrence rates were 86.3% and 80.0%, respectively. The outcomes of surgically treated TETs improved over time. Multivariable Cox hazards analysis for OS, age, tumor size, and Masaoka-Koga stage were independent predictors of prognosis. The World Health Organization classification and tumor-node-metastasis (TNM) staging were also related to the prognosis of TETs. Conclusion: Surgical treatment of TETs achieved a good prognosis with a recent increase in MITS. The M-K stage was the most important prognostic factor for OS and FFR. The new TNM stage could also be an effective predictor of the outcomes of TETs.

Early Clinical Experience in Aortic Valve Replacement Using On-X$^{circledR}$Prosthetic Heart Valve (On-X$^{circledR}$ 기계판막을 이용한 대동맥판 치환술의 조기 임상 경험)

  • 안병희;전준경;류상완;최용선;김병표;홍성범;박종춘;김상형
    • Journal of Chest Surgery
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    • v.36 no.9
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    • pp.651-658
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    • 2003
  • Since the first implanted in September 1997, the use of On-X prosthetic heart valve has been increasing around in the world. This study was designed to assess the feasibility, safety, and the postoperative hemodynamics with this new valve in clinical setting. Material and Method: The current study was carried out on 52 patients undergoing aortic valve replacement with this prosthesis between April 1999 to August 2002 at Chonnam National University Hospital to evaluate the surgical results. 52% of the patients were male and the average age at implant was 50$\pm$13 years. The study followed the guidelines of the AATS/STS. Preoperatively, 32(61.5%) patients were in NYHA functional class III or IV and 2 patients had previous aortic valve surgery. Concomitant cardiac surgery was performed in 71.1%. The implanted valve sizes were 19 mm in 13 patients, 21 mm in 26, 23 mm in 10 and 25 mm in 3, respectively. Mean follow-up was 16.6$\pm$10.5 months (1∼39 months). Echocardiographic assessment was performed pre- and immediate postoperatively, as well as 3, 6, 12 months after surgery, evaluating pressure loss and regression of left ventricular hypertrophy. Result: Mean cardiopulmonary bypass time was 191$\pm$94.7 minutes with an aortic cross-clamp time of 142$\pm$51.7 minutes. There was no early and late mortality, Freedom from adverse events at 1 year in the study were as follows: thromboembolism, 95.6$\pm$6%; bleeding events, 90.2$\pm$4%; paravalvular leakage 92.3$\pm$4%; and overall valve-related morbidity at 1 year was 76.6$\pm$3%. There were no cases of valve thrombosis, prosthetic valve endocarditis and structural or non-structural failure. Left ventricular function at 12 months after surgery (EF=62.7$\pm$9.8%) revealed a statistically significant improvement compared to preoperative investigation (EF=55.8$\pm$15.9%, p=0.006). Left ventricular mass index was 247.3$\pm$122.3 g/$m^2$ on preoperative echocardiographic study, but regressed to 155.5$\pm$58.2 g/$m^2$ at postoperative 1 year (p=0.002). Over the follow-up period a further decrease of peak transvalvular gradients was observed in all patients: 62.5$\pm$38.0 mmHg on preoperative assessment, 18.2$\pm$6.8 mmHg at immediate postoperative period (p < 0.0001), 7.6$\pm$5.09 mmHg (p<0.0001) at 6 month, 18.0$\pm$10.8 mmHg (p<0.0001) at 1 year. Conclusion: The On-X prosthetic heart valve performs satisfactorily in the first 1 year period. Clinical outcome by examining NYHA functional classification revealed especially good results. Effective regression of left ventricular hypertrophy and statistically significant decrease of transvalvular gradient were observed over the first year, but longer-term follow-up of this patient group is needed to establish the expected rates for late valve-related events as well as the long-term clinical efficacy of this valve.