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The Role of Radiation Therapy in the Treatment of Intracranial Glioma : Retrospective Analysis of 96 Cases (뇌 교종 96예에 대한 방사선치료 성적의 후향적 분석)

  • Kim Yeon Sil;Kang Ki Mun;Choi Byung Ock;Yoon Sei Chul;Shinn Kyung Sub;Kang Jun Gi
    • Radiation Oncology Journal
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    • v.11 no.2
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    • pp.249-258
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    • 1993
  • Between March 1983 and December 1989, ninety-six patients with intracranial glioma were treated in the Department of Therapeutic Radiology, Kangnam St. Mary's Hospital, Catholic University Medical College. We retrospectively reviewed each case to evaluate variable factors influencing the treatment results and to develop an optimal therapy Policy. Median follow-up is 57 months (range: 31~133 months). Of the 96 patients, 60 $(63\%)$ were males and 36 $(37\%)$ were females. Ages ranged from 3 to 69 years (median 42 years). The most common presenting symtoms were headeche $(67\%)$ followed by cerebral motor and sensory discrepancy $(54\%),$ nausea and vomiting $(34\%),$ seizure $(19\%),$ mental change $(10\%)$ and memory and calculation impairment $(8\%).$ Eighty five $(88.5\%)$ patients all, except 11 $(11.5\%)$ brain stem lesions, were biopsy proven intracranial glioma. The distribution by histologic type was 64 astrocytomas $(75\%),$ 4 mixed oligoastrocytomas $(5\%),$ and 17 oligodendrogliomas $(20\%).$ Fourty nine patients $(58\%$ were grade I, II histology and 36 $(42\%)$ patients were grade III, IV histology. Of the 96 patients, 64 $(67\%)$ recieved postoperative RT and 32 $(33\%)$ were treated with primary radiotherapy. Gross total resection was peformed in 14 $(16\%)$ patients, subtotal resection En 29 $(34\%),$ partial resection in 21 $(25\%),$ and biopsy only in 21 $(25\%).$ Median survival time was 53 months (range 2~ 133 months), and 2- and, 5-year survival rate were $69\%,49\%$ respectively. 5-year survival rate by histologic grade was grade I, $70\%,$ grade II, $58\%,$ grade III, $28\%,$ and grade IV, $15\%.$ Multivariated analysis demonstrate that age at diagnosis (p=0.0121), Karnofsky performance Status (KPS) (p=0.0002), histologic grade (p=0.0001), postoperative radiation therapy (p=0.0278), surgical extent (p =0.024), cerebellar location of tumor (p=0.0095) were significant prognostic factors influencing on survival.

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Susceptibility of Two Potato Cultivars to Various Environmental Stresses (다양한 환경스트레스에 대한 감자 2품종의 감수성 분석)

  • Tang, Li;Kwon, Suk-Yoon;Sung, Chang-K;Kwak, Sang-Soo;Lee, Haeng-Soon
    • Journal of Plant Biotechnology
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    • v.30 no.4
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    • pp.405-410
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    • 2003
  • Environmental stress is the major limiting factor in plant productivity. In order to evaluate the stress tolerance of potato plants, leaf discs of two potato cultivars, Atlantic and Superior, were subjected to various stress conditions of high temperature, methyl viologen, H2O2, or $H_2O$$_2$. When potato leaf discs were exposed to high temperature at 37$^{\circ}C$ for 84 hr, Atlantic plants, a cultivar with high sensitivity to heat stress, showed about 20% higher membrane damage than Superior plants. When exposed to 2$\mu$M methyl violgen (MV), a superoxide generating non-selective herbicide, for 36 hr, Atlantic plants also showed about 38% higher membrane damage than Superior plants, and were more susceptible up to 10$\mu$M MV concentration tested. On treatment with 0.75M NaCl, Atlantic plants also had about 45% less chlorophyll contents in leaf discs than Superior plants. There was, however, no difference in chlorophyll content of two cultivars at higher NaCl concentrations. The effect of $H_2O$$_2$ on the two cultivars was mixed. At low $H_2O$$_2$ concentration (25 mM) , Superior plants were more susceptible to $H_2O$$_2$stress after 36 hr. However, at high $H_2O$$_2$ concentration (100 mM), Atlantic plants exhibited higher susceptibility after 36 hr. The results indicate that in vitro leaf discs reflecting the whole plants in this study will be useful for selection and characterization of elite transgenic potato plants with enhanced tolerance to environmental stress.

Molecular Epidemiology of Human Astrovirus Infection in Hospitalized Children with Acute Gastroenteritis (급성 위장관염으로 입원한 소아에서 분자 유전학적 방법에 의한 Human Astrovirus 감염의 유병률)

  • Chung, Ju-Young;Huh, Kyung;Kim, Sang Woo;Shin, Bo Mun;Han, Tae Hee;Lee, Jae In;Song, Mi-Ok
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.9 no.2
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    • pp.139-146
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    • 2006
  • Purpose: Human astrovirus (HAstV) is known to be an important etiologic agent of acute gastroenteritis in infants worldwide. However, the prevalence of HAstV infection varies according to geographic region and patient age. The purpose of our study was to investigate the incidence of HAstV infection among hospitalized children at a tertiary hospital in Seoul. Methods: Fecal samples were collected from hospitalized children up to five years of age with acute gastroenteritis. A total of 812 fecal samples were collected from hospitalized children with acute gastroenteritis between February 2004 and January 2005. Fecal specimens were screened for rotavirus, enteric adenovirus and norovirus by enzyme immunoassay (EIA) or reverse transcriptase polymerase chain reaction (RT-PCR). HAstV positive samples were characterized by RT-PCR. Results: Rotavirus was detected in 16.9% (138/812), norovirus in 11.6% (94/812), and adenovirus in 4.0% (33/812) of the study population. HAstV was detected in 4.0% (33/812) samples by RT-PCR. The age distribution of HAstV positive patients was as follows: <12 month old, 82.0% (27/33); 1~2 years old, 6.0% (2/33); 2~5 years old, 12.0% (4/33). The seasonal distribution of HAstV positive samples was as follows; April (3), May (5), June (4), August (12), September (4), October (2), November (2), and December (1). The peak rate of HAstV infection was observed during the summer season, 2004. A mixed infection of viral agents was confirmed in 2.7% (22 /812) of the study population, most commonly with rotavirus and norovirus, and with rotavirus and HAstV. Genotype 1 was the predominant type (91%, 20/22) and genotype 8 was detected in two cases. Conclusion: The prevalence of HAstV infection was 4.0% in hospitalized children with acute gastroenteritis, and was especially high in infants. HAstV can be considered as an important etiologic agent of gastroenteritis in children.

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A Case of the Shoulder-Hand Syndrome Caused by a Crush Injury of the Shoulder (견관절부 외상후 발생된 Shoulder-Hand Syndrome)

  • Jeon, Jae-Soo;Lee, Sung-Keun;Song, Hoo-Bin;Kim, Sun-Jong;Park, Wook;Kim, Sung-Yell
    • The Korean Journal of Pain
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    • v.2 no.2
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    • pp.155-166
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    • 1989
  • Bonica defined, that reflex sympathetic dystrophy (RSD) may develop pain, vasomotor abnoramalities, delayed functional recovery, and dystrophic changes on an affected area without major neurologic injury following trauma, surgery or one of several diseased states. This 45 year old male patient had been crushed on his left shoulder by a heavily laden rear car, during his job street cleaning about 10 years ago (1978). At first the pain was localizea only to the site of injury, but with time, it spreaded from the shoulder to the elbow and hand, with swelling. X-ray studies in the local clinic, showed no bone abnormalities of the affected site. During about 10 years following the injury, the had recieved several types of treatments such as nonsteroidal analgesics, steroid injections into the glenoidal cavity (10 times), physical therapy, some oriental herb medicines, and acupuncture over a period of 1~3 months annually. His shoulder pain and it's joint dysfunction persisted with recurrent paroxysmal aggrevation because of being mismanaged or neglected for a sufficiently long period these fore permiting progression of the sympathetic imbalance. On July 14 1988 when he visited our clinic. He complained of burning, aching and had a hyperpathic response or hyperesthesia in touch from the shoulder girdle to the elbow and the hand. Also the skin of the affected area was pale, cold, and there was much sweating of the axilla and palm, but no edema. The shoulder girdle was unable to move due to joint pain with marked weakness. We confirmed skin temperatures $5^{\circ}C$ lower than those of the unaffected axilla, elbow and palm of his hand, and his nails were slightly ridged with lateral arching and some were brittle. On X-ray findings of both the shoulder AP & lateral view, the left humerus and joint area showed diffuse post-traumatic osteoporosis and fibrous ankylozing with an osteoarthritis-like appearance. For evaluating the RSD and it's relief of pain, the left cervical sympathetic ganglion was blocked by injecting 0.5% bupivacaine 5 ml with normal saline 5 ml (=SGB). After 15 minutes following the SGB, the clinical efficacy of the block by the patients subjective score of pain intensity (=PSSPI), showed a 50% reduction of his shoulder and arm pain, which was burning in quality, and a hyperpathic response against palpation by the examiner. The skin temperatures of the axilla and palm rose to $4{\sim}5^{\circ}C$ more than those before the SGB. He felt that his left face and upper extremity became warmer than before the SGB, and that he had reduced sweating on his axilla and his palm. Horner's sign was also observed on his face and eyes. But his deep shoulder joint pain was not improved. For the control of the remaining shoulder joint pain, after 45 minutes following the SGB, a somatic sensory block was performed by injecting 0.5% bupivacaine 6 ml mixed with salmon calcitonin, $Tridol^{(R)}$, $Polydyn^{(R)}$ and triamcinolone into the fossa of the acromioclavicular joint region. The clinical effect of the somatic block showed an 80% releif of the deep joint pain by the PSSPI of the joint motion. Both blocks, as the above mentioned, were repeated a total of 28 times respectively, during 6 months, except the steroid was used just 3 times from the start. For maintaining the relieved pain level whilst using both blocks, we prescribed a low dose of clonazepam, prazocin, $Etravil^{(R)}$, codeine, etodolac micronized and antacids over 6 months. The result of the treatments were as follows; 1) The burning, aching and hyperpathic condition which accompanied with vaosmotor and pseudomotor dysfunction, disappeared gradually to almost nothing, within 3 weeks from the starting of the blocks every other day. 2) The joint disability of the affected area was improved little by little within 6 months. 3) The post-traumatic osteoporosis, fibrous ankylosis and marginal sclerosis with a narrowed joint, showed not much improvement on the X-ray findings (on April 25, 1989) 10 months later in the follow-up. 4) Now he has returned to his job as a street cleaner.

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Fertilizer and Organic Inputs Effects on CO2 and CH4 Emission from a Soil under Changing Water Regimes (토양 수분 변동 조건에서 시비 및 유기물 투입에 따른 CO2와 CH4 방출 특성)

  • Lim, Sang-Sun;Choi, Woo-Jung;Kim, Han-Yong
    • Korean Journal of Environmental Agriculture
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    • v.31 no.2
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    • pp.104-112
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    • 2012
  • BACKGROUND: Agricultural inputs (fertilizer and organic inputs) and water conditions can influence $CH_4$ and $CO_2$ emission from agricultural soils. This study was conducted to investigate the effects of agricultural inputs (fertilizer and organic inputs) under changing water regime on $CH_4$ and $CO_2$ emission from a soil in a laboratory incubation experiment. METHODS AND RESULTS: Four treatments were laid out: control without input and three type of agricultural inputs ($(NH_4)_2SO_4$, AS; pig manure compost, PMC; hairy vetch, HV). Fertilizer and organic inputs were mixed with 25 g of soil at 2.75 mg N/25 g soil (equivalent to 110 kg N/ha) in a bottle with septum, and incubated for 60 days. During the first 30-days incubation, the soil was waterlogged (1 cm of water depth) by adding distilled water weekly, and on 30 days of incubation, excess water was discarded then incubated up to 60 days without addition of water. Based on the redox potential, water regime could be classified into wetting (1 to 30 days), transition (31 to 40 days), and drying periods (41 to 60 days). Across the entire period, $CH_4$ and $CO_2$ flux ranged from 0 to 13.8 mg $CH_4$/m/day and from 0.4~1.9 g $CO_2$/m/day, and both were relatively higher in the early wetting period and the boundary between transition and drying periods. During the entire period, % loss of C relative to the initial was highest in HV (16.4%) followed by AS (8.1%), PMC (7.5%), and control (5.4%), indicating readily decomposability of HV. Accordingly, both $CH_4$ and $CO_2$ fluxes were greatest in HV treatment. Meanwhile, the lower $CH_4$ flux in AS and PMC treatments than the control was ascribed to reduction in $CH_4$ generation due to the presence of oxidized compounds such as ${SO_4}^{2-}$, $Fe^{3+}$, $Mn^{4+}$, and ${NO_3}^-$ that compete with precursors of $CH_4$ for electrons. CONCLUSION: Green manure such as HV can replace synthetic fertilizer in terms of N input, however, it may increase $CH_4$ emission from soils. Therefore, co-application of green manure and livestock manure compost needs to be considered in order to achieve satisfactory N supply and to mitigate $CH_4$ and $CO_2$ emission.

Current Wheat Quality Criteria and Inspection Systems of Major Wheat Producing Countries (밀 품질평가 현황과 검사제도)

  • 이춘기;남중현;강문석;구본철;김재철;박광근;박문웅;김용호
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47
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    • pp.63-94
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    • 2002
  • On the purpose to suggest an advanced scheme in assessing the domestic wheat quality, this paper reviewed the inspection systems of wheat in major wheat producing countries as well as the quality criteria which are being used in wheat grading and classification. Most wheat producing countries are adopting both classifications of class and grade to provide an objective evaluation and an official certification to their wheat. There are two main purposes in the wheat classification. The first objectives of classification is to match the wheat with market requirements to maximize market opportunities and returns to growers. The second is to ensure that payments to glowers aye made on the basis of the quality and condition of the grain delivered. Wheat classes has been assigned based on the combination of cultivation area, seed-coat color, kernel and varietal characteristics that are distinctive. Most reputable wheat marketers also employ a similar approach, whereby varieties of a particular type are grouped together, designed by seed coat colour, grain hardness, physical dough properties, and sometimes more precise specification such as starch quality, all of which are genetically inherited characteristics. This classification in simplistic terms is the categorization of a wheat variety into a commercial type or style of wheat that is recognizable for its end use capabilities. All varieties registered in a class are required to have a similar end-use performance that the shipment be consistent in processing quality, cargo to cargo and year to year, Grain inspectors have historically determined wheat classes according to visual kernel characteristics associated with traditional wheat varieties. As well, any new wheat variety must not conflict with the visual distinguishability rule that is used to separate wheats of different classes. Some varieties may possess characteristics of two or more classes. Therefore, knowledge of distinct varietal characteristics is necessary in making class determinations. The grading system sets maximum tolerance levels for a range of characteristics that ensure functionality and freedom from deleterious factors. Tests for the grading of wheat include such factors as plumpness, soundness, cleanliness, purity of type and general condition. Plumpness is measured by test weight. Soundness is indicated by the absence or presence of musty, sour or commercially objectionable foreign odors and by the percentage of damaged kernels that ave present in the wheat. Cleanliness is measured by determining the presence of foreign material after dockage has been removed. Purity of class is measured by classification of wheats in the test sample and by limitation for admixtures of different classes of wheat. Moisture does not influence the numerical grade. However, it is determined on all shipments and reported on the official certificate. U.S. wheat is divided into eight classes based on color, kernel Hardness and varietal characteristics. The classes are Durum, Hard Red Spring, Hard Red Winter, Soft Red Winter, Hard White, soft White, Unclassed and Mixed. Among them, Hard Red Spring wheat, Durum wheat, and Soft White wheat are further divided into three subclasses, respectively. Each class or subclass is divided into five U.S. numerical grades and U.S. Sample grade. Special grades are provided to emphasize special qualities or conditions affecting the value of wheat and are added to and made a part of the grade designation. Canadian wheat is also divided into fourteen classes based on cultivation area, color, kernel hardness and varietal characteristics. The classes have 2-5 numerical grades, a feed grade and sample grades depending on class and grading tolerance. The Canadian grading system is based mainly on visual evaluation, and it works based on the kernel visual distinguishability concept. The Australian wheat is classified based on geographical and quality differentiation. The wheat grown in Australia is predominantly white grained. There are commonly up to 20 different segregations of wheat in a given season. Each variety grown is assigned a category and a growing areas. The state governments in Australia, in cooperation with the Australian Wheat Board(AWB), issue receival standards and dockage schedules annually that list grade specifications and tolerances for Australian wheat. AWB is managing "Golden Rewards" which is designed to provide pricing accuracy and market signals for Australia's grain growers. Continuous payment scales for protein content from 6 to 16% and screenings levels from 0 to 10% based on varietal classification are presented by the Golden Rewards, and the active payment scales and prices can change with market movements.movements.

Effects of a Mixed Proportion of Alaska Pollack, Chicken Breast Surimi and Starch on Textural Properties of Sausage (명태 및 닭가슴살수리미와 전분의 혼합비율이 소시지의 조직학적 특성에 미치는 영향)

  • Jin, Sang-Keun;Kim, Il-Suk;Yang, Mi-Ra;Hur, In-Chul;Jung, Hyun-Jung;Yang, Han-Sul;Choi, Yeung-Joon
    • Journal of Animal Science and Technology
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    • v.50 no.4
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    • pp.543-550
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    • 2008
  • This study was conducted to determine the effect of different proportions of Alaska pollack surimi, chicken breast surimi and starch on textural properties of sausage. Sausage were manufactured such as Alaska pollack surimi(control), T1(90.91:0:9.09), T2(80:0:20), T3(62.5:37.5:0), T4(58.82:35.3:5.88), T5 (40:60:0) and T6(36.36:54.55:9.09) depending on different proportions of Alaska pollack surimi, chicken breast surimi and starch. Brittleness, breaking force and gel strength were significantly higher in T1 than the control(P<0.05), and breaking force, gel strength and folding test were significantly higher but sensory evaluation was significantly lower in T2 than the control(P<0.05). Breaking force, gel strength and jelly strength were significantly higher in T3 and T4 than the control(P<0.05). Gel characteristics and sensory scores were significantly higher but texture properties were significantly lower in T5 and T6 than the control(P<0.05). The T3 and T4 had similar textural and sensory properties in the surimi- sausage compared to the control. Therefore, the results of this study indicated that textural properties of sausage can be acceptable when chicken breast surimi replaced Alaska pollack up to 35%.

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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Mitral Valve Reconstruction in Patients with Moderate to Severe Left Ventricular Dysfunction (중등도 이상의 좌심기능부전 환자에서 승모판성형술)

  • Baek, Man-Jong;Na, Chan-Young;Oh, Sam-Sae;Kim, Woong-Han;Whang, Sung-Wook;Kim, Soo-Cheol;Lim, Cheong;Kim, Wook-Sung;Lee, Young-Tak;Kim, Chong-Whan
    • Journal of Chest Surgery
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    • v.36 no.11
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    • pp.812-819
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    • 2003
  • Background: Left ventricular dysfunction is one of the important prognostic factors of early mortality and long-term survival after valve operation. We studied the intermediate term results of mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction. Material and Method: Forty four patients who underwent mitral valve reconstruction with a left ventricular ejection fraction (EF) of <45% or less (20∼45%) from April 1995 through July 2001 were reviewed retrospectively. Ages ranged from 10 to 67 years (46∼14 years) and 32 patients were in NYHA class III-IV. The mitral valve diseases were regurgitation (MR) in 28 patients, stenosis(MS) in 10, and mixed lesion in 5. The etiologies of mitral valve disease were rheumatic in 20 patients, degenerative in 14, ischemic in 5, annular dilatation in 2, congenital in 2, and endocarditis in 1. Operatively, all patients had annuloplasty and/or various valvuloplasty techniques, and a total of 52 procedures were concomitantly performed. Total cardiopulmonary bypass and aortic crossclamp time were 160$\pm$57 minutes and 112$\pm$45 minutes respectively. Result: Two operative deaths occurred as a result of left ventricular failure (4.5%). After the mean follow-up of 39 months (range, 10∼83 months), there was no late death. Transthoracic echocardiography revealed no or grade I of MR in 29 patients (72.5%) and no or mild MS in 35 patients (87.5%). The actuarial survival at 5 years was 100%. Four patients required mitral valve replacement due to progressive mitral valvular disease. The actuarial freedom from valve-related reoperation at 5 years was 84$\pm$9%. Conclusion: This study suggests that mitral valve reconstruction in patients with moderate to severe left ventricular dysfunction offers good early and intermediate survival and acceptable freedom from valve-related reoperation, and it is the strategy for effective management for these patients.

A Study on the Volatility of Global Stock Markets using Markov Regime Switching model (마코브국면전환모형을 이용한 글로벌 주식시장의 변동성에 대한 연구)

  • Lee, Kyung-Hee;Kim, Kyung-Soo
    • Management & Information Systems Review
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    • v.34 no.3
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    • pp.17-39
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    • 2015
  • This study examined the structural changes and volatility in the global stock markets using a Markov Regime Switching ARCH model developed by the Hamilton and Susmel (1994). Firstly, the US, Italy and Ireland showed that variance in the high volatility regime was more than five times that in the low volatility, while Korea, Russia, India, and Greece exhibited that variance in the high volatility regime was increased more than eight times that in the low. On average, a jump from regime 1 to regime 2 implied roughly three times increased in risk, while the risk during regime 3 was up to almost thirteen times than during regime 1 over the study period. And Korea, the US, India, Italy showed ARCH(1) and ARCH(2) effects, leverage and asymmetric effects. Secondly, 278 days were estimated in the persistence of low volatility regime, indicating that the mean transition probability between volatilities exhibited the highest long-term persistence in Korea. Thirdly, the coefficients appeared to be unstable structural changes and volatility for the stock markets in Chow tests during the Asian, Global and European financial crisis. In addition, 1-Step prediction error tests showed that stock markets were unstable during the Asian crisis of 1997-1998 except for Russia, and the Global crisis of 2007-2008 except for Korea and the European crisis of 2010-2011 except for Korea, the US, Russia and India. N-Step tests exhibited that most of stock markets were unstable during the Asian and Global crisis. There was little change in the Asian crisis in CUSUM tests, while stock markets were stable until the late 2000s except for some countries. Also there were stable and unstable stock markets mixed across countries in CUSUMSQ test during the crises. Fourthly, I confirmed a close relevance of the volatility between Korea and other countries in the stock markets through the likelihood ratio tests. Accordingly, I have identified the episode or events that generated the high volatility in the stock markets for the financial crisis, and for all seven stock markets the significant switch between the volatility regimes implied a considerable change in the market risk. It appeared that the high stock market volatility was related with business recession at the beginning in 1990s. By closely examining the history of political and economical events in the global countries, I found that the results of Lamoureux and Lastrapes (1990) were consistent with those of this paper, indicating there were the structural changes and volatility during the crises and specificly every high volatility regime in SWARCH-L(3,2) student t-model was accompanied by some important policy changes or financial crises in countries or other critical events in the international economy. The sophisticated nonlinear models are needed to further analysis.

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