• Title/Summary/Keyword: PRA

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An analysis of Financial Factors' Characteristic for Global Shipping Companies using Panel Regression Analysis (패널회귀분석을 이용한 글로벌 선사의 재무요인 특성분석에 관한 연구)

  • Oh, Jae-Gyun;Yeo, Gi-Tae
    • Journal of Digital Convergence
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    • v.17 no.4
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    • pp.65-73
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    • 2019
  • This study performed Panel Regression Analysis (PRA) with the debt ratio as a dependent variable and the ROE (return on equity), sales volume, current ratio, total capital, and Shanghai Containerized Freight Index (SCFI) as an independent variable. According to the GLS analysis, the current ratio to liabilities ratio was negative, and for sales, the ratio of liabilities was positive. Capital totals also had a negative impact on the debt ratio. However, ROE, unlike the hypothesis, had negative effects on the liability ratio, and the SCFI index was not significant. As implications of this research, the company confirmed that its sales increased as the debt ratio of global shipping companies rose, achieving economies of scale. However, it was confirmed that the actual size of the economy through the injection of other capital would help increase sales but not affect net profit. Shipping companies should expand their business power and secure large container vessels to secure credibility of shippers. In the future research, an analysis considering exchange rate, global economic growth rate, and manufacturing production index is needed.

Low-level Laser Therapy with Novel Array of Light Source and Individualized Program for Treatment of Androgenetic Alopecia: A 16-week, Randomized, Double-blind, Sham Device-controlled Study

  • Kim, Jee-Woo;Kwon, Yeo-Seon;Chang, Yoon-Young;Hong, Sung-Ho;Shin, Jung-Won;Na, Jung-Im;Huh, Chang-Hun
    • Medical Lasers
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    • v.9 no.2
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    • pp.150-158
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    • 2020
  • Background and Objectives Low-level laser therapy (LLLT) is used widely to promote hair growth in androgenetic alopecia (AGA). This study examined the clinical efficacy and safety of a home-use LLLT device with a newly designed array of light sources and software optimized for individual types of AGA. Materials and Methods The study was a randomized, double-blind, sham device-controlled trial. Forty-eight subjects (39 men and nine women) were assigned randomly in a 2:1 ratio to use either the test device (LG Pra'L HGN1, LG electronics, Korea) or sham device. The subjects used the LLLT device three times a week for 16 weeks. Phototrichogram was used to measure the hair density and hair thickness at 0, 8, and 16-weeks. Adverse events were closely monitored. Results After 16 weeks of using the device, the test group showed a significant increase in hair density and hair thickness compared to the control. In the test group, the hair density increased 6.96 counts/cm2 at eight weeks and 13.67 counts/cm2 at 16 weeks from the baseline. The hair thickness increased 7.21 ㎛ at eight weeks and 11.80 ㎛ at 16 weeks compared to the baseline. Conclusion The home-use LLLT device with a novel array of light sources and an individualized program according to the types of hair loss appears to be an effective and safe treatment modality for both male and female AGA patients.

Sprachtypologische Fehleranalyse - Im Vergleich der deutschen und koreanischen Sprache - (독일어와 한국어를 비교한 언어 유형적 분석)

  • Park Jin-Gil
    • Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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    • v.7
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    • pp.1-24
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    • 2003
  • 우리는 지금까지 독일어와 한국어 두 언어간의 오류분석을 논의해 왔다. 특히 언어유형학적인 측면에서 몇 가지 오류유형과 분석을 시도했다. 그 결과는 대체로 다음과 같이 요약될 수 있다. 독일어와 한국어가 서로 근본적으로 상반되는 언어현상과 더불어 약간의 공통성을 나타내며 일정한 유형을 나타낸다. 이는 두로 인간의 언어습득장치에 기인된 언어습득의 결정주의(Determinismus)에서 비롯될 것이다. 언어특성/문제의 체계성/규칙성 또는 일관성은 이를 반영한다. 거대한 언어자료 중에 극히 미미한 일부, 즉 언어최소량를 정복함으로써 그 효용성을 극대화할 수 있는 것은 매우 중요한 의미를 지닌다. 이를 연구 이용하는 경우에는 엄청난 효과와 가능성을 기대할 수 있을 것이다. (1) 독일어와 한국어의 학습 및 오류분석에서 가장 핵심적인 것은 언어유형학적으로 드러난 언어특성, 즉 전치성(독일어/영어)과 후치성(한국어)이다. 이를 토대로 형성된 대립적인 면과 공통적인 문제를 체계화하는 것이 역시 오류분석 문제의 관건이다. 또한 독일어가 아직 후치성 언어(한국어(TXV))에서 출발해서 전치성 언어(영어(SVX))로 발전/변화해 가는 과정, 즉 중간단계인 TVX에 머물고 있다는 사실이 중요한 의미를 지닌다. 즉 그들의 대극성과 유사성을 연결하는 실마리로 볼 수 있기 때문이다. (2) 일치(Kongruenz)/상관(Korrelation) 및 반복(Wiederholung) 현상, 그리고 격변화와 인칭변화 현상은 어순문제와 더불어 형태론적 문제를 통해 문법적인 확인수단으로 작용한다. 이들은 대부분 체계적/구조적으로 나타나기 때문에 학습자는 흔히 같은 유형에서 반복적으로 오류를 범하기 마련이다. 이를 극복하기 위해서 언어 유형학적 오류분석을 이해하고 또한 이를 통해 오류를 줄이거나 예방하는 학습이 필요하다. (3) 명사가 한정사구 안에서 성/수/격에 따라 변화하는 것과 동사가 동사구에서 주어의 인칭/수에 따라 인칭변화 하는 것은 우리 한국인에게는 아주 이색적인 현상이다. 이는 양면적인 수식구조에 대한 확인수단 및 원자가에 의한 강력한 형식위주 언어인 독일어와 전위적인 단일 수식구조와 부정형 동사를 특성으로 형성된 핵/최소문 언어간의 필연적인 적응관계 및 결과라고 볼 수 있다. 이 두 가지 유형 역시 언어특성에 따라 도식화/공식화 할 수 있다. (4) 괄호현상, 즉 으뜸머리(Hauptkopf)가 버금머리(Nebenkopf)와 분리하는 것은 우리 한국인에게는 아주 이색적인 언어현상이다. 한국어에는 머리의 이동이 없기 때문이다. 긴 구문에서 버금머리를 잊어버리거나 실수하는 것은 모든 괄호구문에서 예견되는 결과이다. 그러나 이는 정치성과 후치성 언어간의 전이 과정으로 이해될 수 있다. 으뜸머리가 원래의 자리를 박차고 소속 구/문의 앞자리로 도약한 것처럼 느껴지기 때문이다. (5) 전치 및 후치 수식이 유동적으로 작용하는 독일어는 전치 수식만으로 고정된 한국어보다 복잡하지만 균형적인 언어구조이다. 이러한 수식구조에서 한국인은 흔히 형태 및 어순에서, 그리고 번역에서 오류를 범하고 만다. (6) 그러나 가장 중요한 것은 아는 것을 제대로 이용하는 문제이다. 모국어/L2를 자유로이 말하고 쓸 때까지, 즉 언어습득에는 일체이 문법이나 도표/도식을 이용할 필요가 없다는 사실이다. 이는 17세기 서구의 이성주의 철학자들의 한결같은 경고이다. 오늘날 초고속 과학문명에서 더욱 빛을 발하는 것은 당연한 결과이다. 한 언어 속에 들어있는 문법체계를 익혀 가는 것이 곧 언어습득 과정이지만, 이를 달성하는 가능성 내지 첩경은 실제적인 언어자료와 체험이지 결코 문법이나 추상적인 개념적 접근이 아님을 웅변하고 있기 때문이다. 핵심적인 문제는 모국어교육에서도 최대 장점인 대화를 통한 언어연습/대화 기회를 최대한 보장하는 데 있다. 또한 언어간섭 현상을 조장하는 분위기를 막아야 할 것이다. 이러한 의미에서 교수법 개발이 외국어/L2 성공의 관건일 것이다. (7) 언어학습에서 오류를 극복하는 데는 일차적인 실제 상황에 부합하는 대화적인 연습, 그리고 효과적인 언어자료 접촉, 즉 독서와 모방이 중요하다. 이차적이고 직접적인 것은 통사(Syntax) 및 형태론(Morphologie)를 익힐 수 있는 말/문을 끊임없이 익히는 일이다. 이것이 또한 언어최소량을 충족시켜 언어습득에 이르는 첩경이다. 자연 생태적인 모국어 학습 또는 조정 및 제도적인 언어학습에서도 실제상황에 어긋나는 문법적인 체계에 얽매이는 도식 및 도표 위주의 텟스트는 일시적인 기대일 뿐이다. 인간의 언어습득장치를 이해하지 못한 결과이기 때문이다. 문법적인 개념위주 접근은 상당한 설명이 필요해서 절박한 자료와 체험까지 앗아가기 마련이다. 더구나 이를 위해 수준을 무시하고 모국어로 일관하여 벙어리와 문맹을 자초하는 것은 참으로 어리석은 일이다. 지식 정보화 시대 및 세계화 시대에는 무엇보다도 교육 및 언어정책이 국가 발전의 원동력이다. 특히 영어를 비롯한 외국어 학습능력과 학습방법은 매우 중요하다. 학습자에게 말하고 쓰는 기본 능력을 보장하는 것이 급선무이다. 이를 위한 작업의 하나가 바로 언어간의 오류분석일 것이다. 언어의 습득과 활용이 체계적이듯이 오류분석 역시 상당히 체계적이다. 그래서 인간의 언어습득과 언어습득장치를 두고 결정론(Determinismus)이 지배적이다. 이러한 의미에서 언어습득의 3대 요소, 즉 언어습득장치를 구비한 인간으로 태어나고, 해당 언어를 통한 일관된 언어체험/학습으로 언어최소량을 충족해야 한 언어를 정복할 수 있다는 것은 결정적인 사실이다. 학생고객에게 다가서는 책임교육으로 교육개방에 대비하는 일 역시 시대적인 상황이요 또한 결정적인 단계임엔 틀림이 없을 것이다.

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Development of Intelligent Database Program for PSI/ISI Data Management of Nuclear Power Plant (원자력발전소 PSI/ISI 데이터 관리를 위한 지능형 데이터 베이스 프로그램 개발)

  • Park, Un-Su;Park, Ik-Keun;Um, Byong-Guk;Park, Yun-Won;Kang, Suk-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.18 no.5
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    • pp.389-397
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    • 1998
  • For an effective and efficient management of large amounts of preservice/inservice inspection(PSI/ISI) data in nuclear power plants, an intellegent Windows 95-based data management program was developed. This program enables the prompt extraction of previously conducted PSI/ISI conditions and results so that the time-consuming data management, painstaking data processing and analysis in the past are avoided. The program extracts, and the associated remedies. Furthermore, additional inspection data and comments can be easily added or deleted for subsequent PSI/ISI operation. Although the initial version of the program was applied to Kori nuclear power plant, this program can be equally applied to other nuclear power plant. And also this program can be used to offer the fundamental data for application of evaluation data related to fracture mechanics analysis(FMA), probabilistic reliability assessment(PRA) of PSI/ISI results, performance demonstration initiative(PDI) and risk-informed ISI based on probability of detection(POD) information of ultrasonic examination. Besides, the program can be further developed as a unique PSI/ISI data management expert system that can be apart of PSI/ISI data management expert system that can be a part of PSI/ISI Total Support System(TSS) for Korean nuclear power plants.

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Development of a Fire Human Reliability Analysis Procedure for Full Power Operation of the Korean Nuclear Power Plants (국내 전출력 원전 적용 화재 인간신뢰도분석 절차 개발)

  • Choi, Sun Yeong;Kang, Dae Il
    • Journal of the Korean Society of Safety
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    • v.35 no.1
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    • pp.87-96
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    • 2020
  • The purpose of this paper is to develop a fire HRA (Human Reliability Analysis) procedure for full power operation of domestic NPPs (Nuclear Power Plants). For the development of fire HRA procedure, the recent research results of NUREG-1921 in an effort to meet the requirements of the ASME/ANS PRA Standard were reviewed. The K-HRA method, a standard method for HRA of a domestic level 1 PSA (Probabilistic Safety Assessment) and fire related procedures in domestic NPPs were reviewed. Based on the review, a procedure for the fire HRA required for a domestic fire PSA based on the K-HRA method was developed. To this end, HRA issues such as new operator actions required in the event of a fire and complexity of fire situations were considered. Based on the four kinds of HFE (Human Failure Event) developed for a fire HRA in this research, a qualitative analysis such as feasibility evaluation was suggested. And also a quantitative analysis process which consists of screening analysis and detailed analysis was proposed. For the qualitative analysis, a screening analysis by NUREG-1921 was used. In this research, the screening criteria for the screening analysis was modified to reduce vague description and to reflect recent experimental results. For a detailed analysis, the K-HRA method and scoping analysis by NUREG-1921 were adopted. To apply K-HRA to fire HRA for quantification, efforts to modify PSFs (Performance Shaping Factors) of K-HRA to reflect fire situation and effects were made. For example, an absence of STA (Shift Technical Advisor) to command a fire brigade at a fire area is considered and the absence time should be reflected for a HEP (Human Error Probability) quantification. Based on the fire HRA procedure developed in this paper, a case study for HEP quantification such as a screening analysis and detailed analysis with the modified K-HRA was performed. It is expected that the HRA procedure suggested in this paper will be utilized for fire PSA for domestic NPPs as it is the first attempt to establish an HRA process considering fire effects.

1 Case of Primary Aldosteronism Caused by Adrenal Hyperplasia (부신증식으로 인한 원발성 Aldosterone증 1예)

  • Park, Shie-Hwoa;Choi, Soo-Bong;Kim, Chong-Suhl
    • Journal of Yeungnam Medical Science
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    • v.3 no.1
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    • pp.313-318
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    • 1986
  • Primary aldosteronism is a disease that the stimulus for the excessive aldosterone production resides within the adrenal gland. It was first described by conn in 1955. And many cases were reported by physicians at present in the world. But it is relatively rare in Korea, probably due to lack of attension and medical facilities. Only about 13 cases have been reported at present. The clinical, biochemical features in 1 case of primary aldosteranism caused by adrenal hyperplasia that was diagnosed at Yeungnam University Hospital was observed and the following result were obtained. 1. Clinical feature: The present case was 27-year-old woman who was admitted due to general weakness and easy fatigability. The above mensioned chief complaints occurred 8 months prior to admission when she delivered of second baby by cesarian section. Symptoms such as above chief complaints, intermittent muscle paralysis and cramping were noticed. Trousseau's sign was also present. The average blood pressure ranged from 170/90 to 200/120. 2. Biochemical abnormalities: Severe hypokalemia lower than 2.5 mEq/L was presented and 24 hours urine potassium showed markedly increased urinary loss.(228 mEq/day). Plasma renin activity was decreased under normal range with furosemide administration.(Basal renin; 0.01ng/ml/hr, stimulated renin 0.12ng/ml/hr). Saline suppression test revealed markedly elevated levels of aldosterone higher than normal range. (Basal aldosterone; 320.68pg/ml stimulated aldosterone; 451.86pg/ml). And posture test showed decreased plasma renin activity and increased plasma aldosterone level. - PRA(ng/ml/hr)=Bsal: 0.05(0.15~2.33), Stimulated: 0.22(1.31~3.95) - Aldosterone(pg/ml)=Bsal: 242.77(10~160), Stimulated: 432.09(40~310) 3. Adrenal CT scan revealed no abnormal findings. 4. Treatment and course: Spironolactone was given at OPD with regular follow-up. Her blood pressure ranged from 150/90 to 160/100 and symptoms were improved. The effect of treatment was satisfactory and further follow up would be performed.

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Interaction between norepinephrine and angiotensin II on Na+ uptake in primary cultured rabbit renal proximal tubule cells (초대배양한 토끼 신장 근위세뇨관세포의 Na+ uptake에 대한 norepinephrine 과 angiotensin II의 상호작용)

  • Park, Soo-hyun;Koh, Hyun-ju;Han, Ho-jae
    • Korean Journal of Veterinary Research
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    • v.38 no.3
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    • pp.525-534
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    • 1998
  • 신장 근위세뇨관세포들은 사구체에서 여과된 물질의 재흡수, 분비 및 대사에 관여하는 여러 호르몬들의 수용체들을 가지고 있다. 이들중에서 norepinephrine(NE)과 angiotensin II(ANG II)는 $Na^{+}/H^+$ 상호운반계를 조절함으로써 혈압조절에 관여하는 것으로 알려져 있으나 이들의 상호관계에 대해선 연구보고가 많지 않다. 본 연구는 초대배양한 토끼신장 근위세뇨관세포를 이용한 $Na^+$ uptake 실험을 통하여 NE이 어떠한 수용체를 통하여 $Na^{+}/H^+$ 상호운반계를 조절하는지 그리고 이러한 작용에 있어서 NE과 ANG II의 상호관계를 알아보고자 실시하였다. NE(>$10^{-9}M$)은 $Na^+$ uptake를 유의성 있게 증가시켰다($10^{-9}M$ NE : $27{\pm}4%$ increase vs. Control;p < 0.05). $\alpha$ 길항제(phentolamine, $10^{-10}M$)는 NE($10^{-9}M$)에 의해 유도된 $Na^+$ uptake를 유의성 있게 차단하였으나 (phentolamine+NE : $29{\pm}5%$ inhibition vs. NE ; p〈 0.05), ${\alpha}_1$ (pra-zosin, $10^{-10}M$) 및 ${\alpha}_2$ 길항제(yohimbine, $10^{-10}M$)는 부분적으로 차단하였다. ${\beta}$ 길항제(propra-nolol, $10^{-10}M$)도 역시 NE에 의해 유도된 $Na^+$ uptake를 유의성 있게 차단하였으나(propranolol+NE : $24{\pm}6%$ inhibition vs. NE ; p< 0.05), ${\beta}_1$(atenolol, $10^{-10}M$) 및 ${\beta}_2$ 길항제(butoxamine, $10^{-10}M$)는 부분적으로 차단하였다. 이러한 결과들은 NE에 의해 유도된 $Na^+$ uptake 증가작용은 ${\alpha}$(${\alpha}_1$${\alpha}_2$ )와 ${\beta}$(${\beta}_1$${\beta}_2$) 수용체 모두를 통하여 일어난다는 것을 시사해주고 있다. ANG II($10^{-11}M$) 또는 NE(${\alpha}_1$, ${\alpha}_2$, ${\beta}_1$, ${\beta}_2$ 작동제) 단독처리군의 $Na^+$ uptake는 대조군에 비해 유의성 있게 증가하였으나 (ANG II : $23{\pm}9%$ increase vs. Control; p < 0.05), 병합처리시 상승작용은 나타나지 않았다. ${\alpha}$ 또는 ${\beta}$ 길항제 처리시 NE 및 ANG II에 의해 유도되었던 $Na^+$ uptake 증가는 유의성 있게 차단되었다(phentolamine+NE+ANG II : $25{\pm}3%$ inhibition, propranolol+NE+ANG II : $24{\pm}6%$ inhibition vs. NE+ANG II, respectively ; p〈 0.05). 이 결과들은 $Na^+$ uptake에 있어서 ${\alpha}$(${\alpha}_1$${\alpha}_2$)와 ${\beta}$(${\beta}_1$${\beta}_2$) 수용체와 ANG II의 관련성을 시사해 준다. 결론적으로 토끼 신장 근위세뇨관세포에서 NE은 ${\alpha}_1$, ${\alpha}_2$, ${\beta}_1$${\beta}_2$ 수용체를 통하여 $Na^+$+ uptake를 증가시켰으며 이들 수용체는 ANG II $Na^+$ uptake 증가작용에 관여하였다.

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A Case of Neonatal Alloimmune Thrombocytopenia due to Anti-HLA-B35 (항-HLA-B35 항체에 의한 신생아 동종면역성 혈소판 감소증 1례)

  • Choi, Jun-Seok;Kim, Soo-Yeon;Ihm, Chun-Hwa;Kim, Seung-Yeon
    • Neonatal Medicine
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    • v.16 no.2
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    • pp.248-254
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    • 2009
  • Neonatal alloimmune thrombocytopenia (NAIT) is induced by maternal antibodies to fetal platelet alloantigens. Because the main cause of NAIT is incompatibility to platelet specific antibodies, NAIT due to HLA antibodies are relatively rare. We managed a case of NAIT induced by maternal anti-HLA-B35 antibodies. The patient was a second born male. He had no petechiae or purpura at birth. He was admitted to the hospital due to fever for 5 days and a platelet count of $106\times10^9/L$. The fever subsided after admission but on the 2nd day of admission, petechiae developed on the chest wall and the platelet count decreased to $25\times10^9/L$. Other laboratory findings included C-reactive protein, prothrombin time, and partial thromboplastin time were normal. His mother's platelet count was normal and she had no history of bleeding. Anti-HLA-B35, B52, B56, C3, and C14 were identified in the mother's serum by a panel reactive antibody test and HLA-B35 antigen was identified in the father's and patient's sera. These finding suggested that maternal Anti-HLA-B35 antibody was a response to neonatal HLA-B35 antigen inherited from the father. The patient received concentrated platelet and intravenous immunoglobulin. The platelet count rose to $248\times10^9/L$ and was maintained thereafter.

Differential Function of EDRF in Systemic Arterial and Pulmonary Arterial System of Renal Hypertensive Rats (신성 고혈압쥐의 전신성 동맥계와 폐동맥계에 대한 EDRF 기능의 차이)

  • Lee, Byung-Ho;Shin, Hwa-Sup;Huh, In-Hoe
    • The Korean Journal of Pharmacology
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    • v.29 no.2
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    • pp.213-223
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    • 1993
  • To investigate the endothelium dependent vascular reactivity of the systemic arterial and the pulmonary arterial system in acute renal hypertensive rats of 2-kidney, 1-ligation type (RHRs), acetylcholine (ACh)-induced vasodilation and depressor effects were evaluated in isolated arteries and in vivo, respectively, in the presence and absence of functional endothelium. ACh $(10^{-5}\;M)$ relaxed the intact thoracic aortas from RHRs and normotensive rats (NRs), but the effect was significantly smaller for those from RHRs (34 and 86%, respectively, p<0.01). ACh-induced vasodilation was completely abolished after removal of endothelial cell or pretreatment with EDRF inhibitors, L-NAME and MB, indicative of its dependence on intact endothelial or EDRF function. ACh also induced vasorelaxation of the intact pulmonary arteries from RHRs and NRs; however, unlike the effects on the thorcic aorta, no significant difference in amplitude was noted between two groups. ACh $(0.1{\sim}10\;{\mu}g/kg,\;i.v.)$ reduced mean systemic arterial pressure in anesthetized RHRs and in NRs to the similar magnitude (% change: 39 and 46% at $10\;{\mu}g/kg$, respectively) and these hypotensive effects were significantly decreased after pretreatment with L-NAME (30 mg/kg, i.v.). Deprssor effects of ACh on mean pulmonary arterial pressure were similar in RHRs and NRs with and without pretreatment of L-NAME. However, in both NRs and RHRs, the depressor effects of ACh on mean pulmonary arterial pressure were significantly reduced compared with those for mean systemic arterial pressure, and the increment of mean pulmonary arterial pressure noted after L-NAME $(0.1{\mu}100\;mg/kg,\;i.v.)$ was significantly smaller than that for mean systemic arterial pressure. These results indicate that in RHRs the endothelial cell function was impaired, at least in part, in systemic arterial system, but not in pulmonary arterial system, and both ACh-evoked and basal release of EDRF was less in the pulmonary arterial system than in systemic arterial system of both NRs and RHRs.

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Clinical Significance of Low-colony Count Scotochromogen Nontuberculous Mycobacteria (균집락수가 적은 암색소성 비결핵항산균 배양의 임상적 의미)

  • Lee, Jung Yeon;Kim, Mi-Na;Chung, Hee-Jung;Jun, Kyung Ran;Choi, Hee Jin;Lee, Hyeyoung;Joung, Eun Young;Oh, Yeon-Mok;Lee, Sang Do;Kim, Woo Sung;Kim, Dong Soon;Kim, Won Dong;Shim, Tae Sun
    • Tuberculosis and Respiratory Diseases
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    • v.59 no.1
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    • pp.39-46
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    • 2005
  • Background : Even though it has been suggested that low-colony, scotochromogen nontuberculous mycobacteria (NTM) are usually contaminants and not true pathogens, evidence for this hypothesis has not been provided. This study investigated the colony characteristics, organism identification, and clinical significance of low-colony scotochromogen. Methods : The laboratory cultured 6,898 respiratory clinical specimens for an examination of mycobacteria over a three-month period. A low-colony count was arbitrarily defined as ${\leq}20$ colonies. This study analyzed the recovery rate of the mycobacteria, the number of colonies and their gross characteristics, and their clinical significance. PCR-restriction fragment length polymorphism analysis was carried out to identify the NTM species. NTM pulmonary disease was defined according to the American Thoracic Society. Results : A total of 6,898 respiratory specimens for mycobacterium were cultured. Of these, 263 (3.8%) grew NTM, and 382 (5.5%) grew M. tuberculosis. Of the 263 cultured NTM specimens, 124 (47.1%) were scotochromogens. The smear-positive rate was significantly lower in these scotochromogens (4.8%) than in the non-scotochromogens (23.7%) (p<0.05). The most common isolates were M. gordonae (83/102, 81.4%) in the scotochromogens, and MAC (52/121, 43.0%) in the non-scotochromogens. Even though three out of 113 patients with a low-colony scotochromogen has been diagnosed with NTM pulmonary disease, the isolated scotochromogen was not considered to be the cause of the NTM disease but was just a contaminant. Conclusion : In this study, the most common isolate of a low-colony count scotochromogen was M. gordonae, which appeared to be contaminants and not true pathogens. Greater efforts in the quality control of a mycobacterium laboratory are needed in cases where there is a high recovery rate of low-colony count scotochromogen.