• 핵의학기술
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• 제14권1호
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• pp.73-77
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• 2010

핵의학 기술학의 발전은 많은 변화를 가져왔다. 하드웨어적인 발전이 많이 있었고 또한 소프트웨어의 발전도 핵의학 기술학 발전에 지대한 공을 세웠다. 소프트웨어의 발전으로 그 동안 수동으로 설정해야 했던 많은 ROI를 자동으로 설정할 수 있게 되었다. automated ROI가 manual ROI와 어떠한 정량분석의 차이를 가지고 있는지 알고자 한다. 분석은 3가지의 분석을 통해 결론을 도출하고자 하였다. 분석 1은 신장 automated ROI와 신장 manual ROI를 비교하였다. 분석 2는 threshold의 크기변화에 따른 차이를 조사하였다. 육안적 판단으로 신장의 외곽선보다 큰 threshold ROI(이하 A threshold), 외곽선과 일치하는 threshold ROI(이하 B threshold), 외곽선보다 작은 threshold ROI(이하 C threshold)를 설정하여 신장의 기능 값을 구하여 이를 비교 하였다. 분석 3은 automated background ROI를 세 가지 full, half, quarter로 분류하여 이에 따른 기능값의 차이를 분석하였다. 분석 1에서 신장 automated ROI와 신장 manual ROI간에 통계적으로 유의한 차이는 보이지 않았다. 그러나 분석 2에서 C threshold는 각 A threshold와 B threshold 간에 유의한 차이 (p<0.01)를 보였다. 분석 3은 분석 1을 통해 얻어진 결론을 토대로 시행되었다. 각 3가지 형태의 background에서 full background가 통계적으로 유의한 차이를 보였다(p<0.05). automated ROI가 manual ROI와 유의한 차이를 보지 않아 입증된 결과는 사용자의 편의와 객관성이 증대될 것으로 기대된다. 분석 2에서는 신장의 외곽선보다 작게 설정된 threshold는 신장의 외곽선보다 크게 설정된 threshold보다 큰 오차를 가질 수 있다는 것을 예상할 수 있다. 분석 3은 신장 주변의 간과 비장에 background가 증가되어 초래된 결과로 예상한다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권2호
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• pp.237-242
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• 2001

Colostrum deprived, newborn pigs (N=12, $1.64{\pm}0.05kg$) were used to study the renal threshold of carnitine, and effects of emulsified medium-chain triglyceride (MCT, tri-8:0) feeding on kinetics of plasma carnitine and urinary carnitine excretion. An arterial catheter was inserted through an umbilical artery, and a bladder catheter was inserted via the urachus. Piglets were oro-gastrically gavaged with one of six carnitine levels (0, 60, 120, 180, 240, $480{\mu}mol/kg\;W^{0.75}$) with (+MCT) or without medium-chain triglycerides (-MCT) in 0.9% NaCl solution. Blood was sampled into heparinized tubes at 0, 1, 2, 4, 6, 8, 14, and 20 h after gavage, and urine was collected and pooled into 1 h or 2 h composite samples to determine free- and short-chain carnitine concentrations. Plasma from the 12 newborn piglets before gavage contained $10.6{\pm}1.2{\mu}mol/L$ free carnitine and $7.2{\pm}0.6{\mu}mol/L$ acid-soluble acyl carnitine. The renal threshold for carnitine was similar between the MCT and the +MCT group (42.6 13.1 and $46.4{\pm}2.0{\mu}mol/L$, respectively), but the correlation between plasma free carnitine and urinary excretion was altered. Plasma free carnitine linearly increased with increasing carnitine dosage (-MCT group, $R^2=0.95$, p<0.001; +MCT group, $R^2=0.91$, p<0.001), but was decreased by 50% when medium-chain triglycerides were fed. The peak in plasma free carnitine concentration was depressed by medium-chain triglycerides feeding also. Therefore, the plasma and urinary short-chain/free carnitine ratio of the +MCT group was increased by 100% and 40%, respectively (p<0.01). Feeding of medium-chain triglycerides may delay plasma carnitine elevation via altering the kinetics of absorption. Similarly, the plasma and urinary short-chain/free carnitine ratio were affected by interaction between medium-chain triglycerides and time (p<0.01). The present study suggests that an oral carnitine dose over $480{\mu}mol/kg\;W^{0.75}$ may be needed to reach the free carnitine renal threshold within a short period, especially when provided together with medium-chain triglyceride.

• 한국임상수의학회지
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• 제22권4호
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• pp.420-423
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• 2005

A 2-year-old 16-kg, intact female lindo was presented with weight loss and poor hair coat. Abnormal serum biochemical values included mild hypokalemia (3.9 mmol/L, reference range 4.37 to 5.35 mmol/L) and mild hyperglycemia (124 mg/dl, reference range 65 to 118 mg/dl). in the complete blood count and diagnostic imaging examination, abnormal changes wer not seen. The analysis of urine sample obtained from cystocentesis revealed glucosuria (> 100 mg/dl) and mild proteinuria. Repeated analysis after admission showed persistent glucosuria and hypokalemia. But blood glucose values did not exceed the renal threshold fur glucose reabsorption. To differentiate cause of the glucosuria, the glucose tolerance test and the low-dosage dexamethasone suppression test were indicated. Results of both tests were normal. In addition, the serum total thyroxine $(T_4)$ value was within normal range. The arterial blood gas analysis showed no remarkable changes. The fractional reabsorption rates of amino acids and phosphorus were calculated above $97\%$. Based on these findings, the dog was diagnosed as renal glucosuria due to proximal renal tubular dysfunction. But this persistent renal glucosuria with hypokalemia may be the initial sign of Fanconi's syndrome or proximal renal tubular acidosis.

• The Korean Journal of Physiology and Pharmacology
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• 제3권3호
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• pp.351-356
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• 1999

The present study was aimed at investigating whether the calcium current in the vascular smooth muscle (VSM) cells is altered in renal hypertension. Two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertension were made in Sprague-Dawley rats. Rats without clipping the renal artery or implanting DOCA were used as control for 2K1C and DOCA-salt hypertension, respectively. Four weeks after clipping, systolic blood pressure was significantly higher in 2K1C rats than in control $(192{\pm}24\;and\;119{\pm}4$ mmHg, respectively, n=16 each). DOCA-salt rats also showed a higher blood pressure $(180{\pm}15$ mmHg, n=18) compared with control $(121{\pm}6$ mmHg, n=14). VSM cells were enzymatically and mechanically isolated from basilar arteries. Single relaxed VSM cells measured $5{\sim}10\;{\mu}m$ in width and $70{\sim}150\;{\mu}m$ in length were obtained. VSM cells could not be differentiated in size and shape between hypertensive and normotensive rats under light microscopy. High-threshold (L-type) calcium currents were recorded using whole-cell patch clamp technique. The amplitude of the current recorded from VSM cells was larger in 2K1C hypertension than in control. Neither the voltage-dependence of the calcium current nor the cell capacitance was significantly affected by 2K1C hypertension. By contrast, the amplitude of the calcium current was not altered in DOCA-salt hypertension. These results suggest that high-threshold calcium current of the VSM cells is altered in 2K1C hypertension, and that calcium channel may not be involved in calcium recruitment of VSM in DOCA-salt hypertension.

• 한국의학물리학회지:의학물리
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• 제12권1호
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• pp.41-50
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• 2001

신장 핵의학 영상의 정량적 분석시 설정하게 되는 관심영역은 그 설정 위치 및 모양과 크기에 따라 서로 다른 분석 결과를 도출하게 한다. 따라서, 관심영역을 사용자가 직접 육안으로 판별하여 수동으로 설정하는 경우, 사용자별 주관적 요소에 의해 위치 및 형태가 서로 상이한 관심영역을 설정하게 되어 동일한 자료를 분석하더라도 그 결과가 모두 상이한 값을 갖게 되는 문제점이 발생한다. 본 연구에서는 관심영역 수동설정시 사용자별 관심영역 설정의 변화도가 실제 신장기능 분석결과에 어느 정도의 영향을 주는지를 조사하였으며, 수동설정시보다 일관성 있는 결과를 얻기 위해 여러방법의 자동설정 기능을 개발하여 그 적용 결과를 분석하였다. 관심영역의 설정에 따른 결과분석을 위한 지표값으로 좌ㆍ우 신장의 상대적 섭취도, 사구체여과율 및 평균통과시간을 선정하였고, IDL5.2로 프로그래밍하여 분석용 도구로서 적합한 소프트웨어를 개발하였으며, $^{99m}$ Tc-DTPA를 주입하여 얻은 총 11명의 정상인 신장 핵의학 영상을 대상으로 9명의 사용자들이 수행한 신장기능 평가 결과를 분석하였다. 신장 관심영역의 자동설정을 위해 영상내 화소들의 gradient값을 이용한 역치(threshold)의 계산과 border tracing기법을 적용하였으며, 배후 관심영역과 대동맥의 관심영역은 좌ㆍ우 신장의 관심영역이 설정 완료된 후, 영상내 기하학적 정보와 화소값을 참조로 하여 자동으로 설정되도록 하였다. 신장 관심영역의 자동설정 기능으로 사용자 주관적 요소의 배제 정도에 따라 4가지 방법을 개발하였으며, 각각의 적용결과를 비교, 분석하였다. 이 4가지 관심영역 자동설정 기능들은 그 구현 방법에 따라 조금씩의 차이는 있었지만, 수동설정시보다 정량적 분석 결과값의 사용자별 편차를 확연히 감소시켜, 신장 핵의학 영상의 정량적 분석시 객관적 기준을 통한 일관성 있는 결과를 도출함에 있어 그 기능의 상대적 우수성을 입증하였다.

• Journal of Biosystems Engineering
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• 제38권2호
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• pp.129-137
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• 2013

Purpose: Modeling has been used for elucidating the mechanism of complex biosystems. In spite of importance and uniqueness of adolescent calcium (Ca) metabolism characterized by a threshold Ca intake, its regulatory mechanism has not been covered and even not proposed. Hence, this study aims at model-based proposing potential mechanisms regulating adolescent Ca metabolism. Methods: Two different hypothetic mechanisms were proposed. The main mechanism is conceived based on Ca-protein binding which induces renal Ca filtration, while additional mechanism assumed that active renal Ca re-absorption regulated Ca metabolism in adolescents. Mathematical models were developed to represent the proposed mechanism and simulated them whether they could produce adolescent Ca profiles in serum and urine. Results: Simulation showed that both mechanisms resulted in the unique behavior of Ca metabolism in adolescents. Based on the simulation insulin-like growth factor-1 (IGF-1) is suggested as a potential regulator because it is related to both growth, a remarkable characteristic of adolescence, and Ca metabolism including absorption and bone accretion. Then, descriptive modeling is employed to conceptualize the hypothesized mechanisms governing adolescent Ca metabolism. Conclusions: This study demonstrated that modeling is a powerful tool for elucidating an unknown mechanism by simulating potential regulatory mechanisms in adolescent Ca metabolism. It is expected that various analytic applications would be plausible in the study of biosystems, particularly with combination of experimental and modeling approaches.

• Biomolecules & Therapeutics
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• 제10권4호
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• pp.258-267
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• 2002

In this study the general pharmacological profiles of AS6 on the central nervous system, cardiovascular and the other organs were investigated. The dosages given were 0, 250, 500 and 1000 mg/kg and drugs were orally administered. The animals used for this study were mice, rats and guinea pigs. Significant increases (p<0.01) in the charcoal transport capacity were observed at the high dose of 1000 mg/kg and significant increases in retardation of pain threshold were observed in the test using acetic acid in all dosed animals. However, AS6 showed no noticeable effects on general behavior, motor coordination, spontaneous locomotor activity, hexobarbital-induced sleep time, body temperature, analgesic activity in the test using hot plate method and anticonvulsant activity. Furthermore no noticeable effects were observed in cardiovascular functions in the isolated rat heart, contraction and relaxation of the smooth muscle in the isolated guinea ileum, gastric secretion and renal function.

• Journal of Nutrition and Health
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• 제38권9호
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• pp.706-716
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• 2005

High blood pressure is an important determinant of the incidence of coronary heart disease, stroke, congestive heart failure, renal failure, and peripheral vascular disease. Recommendations for control of high blood pressure emphasize lifestyle modification, including weight control, reduced sodium intake, increased physical activity. Subjects who were normotensive (n=19, $47.2\pm9.0$ y, BP l16/81 mmHg) ,treatment hypertensive (n=33, $54.2\pm6.9$ y, BP 132/85 mmHg) and non-treatment hypertensive (n=14, $50.1\pm11.0$ y, 149/94 mmHg) recruited. Anthropometric assessment (height weight waist circumference, hip circumference, fat$\%$, fat mass, and lean body mass) and dietary assessments (using 3-days food records, daily nutrient intakes were inuysed by CAN PRO 2.0 were carried out. Blood and 24-hour urine were collected). Test of recognition for salt taste threshold were performed. In non-treatment hypertensive male subjects, weight, $\%$IBW, BMI, and waist circumference were significantly higher than those of normotensive and treatment hypertensive subjects (p<0.05) .Food habits were not significantly different among the three groups. Intakes of vitamin A, vitamin B,, and vitamin B, were significantly higher in normotensive group (p<0.05). Intakes of sodium and salt taste recognition threshold were the highest in normotensive group and the lowest in treatment hypertensive group (p<0.05). Blood levels of lipids and minerals were not significantly different among the three groups. Urinary calcium level of normotensive group were significantly higher than that of treatment hypertensive and non-treatment hypertensive groups (p<0.05). These results indicate that continuous management of hypertension by drug and non-drug treatment affects salt taste recognition threshold and reduced the consumption of sodium. However, dietary sodium intake exceed recommended sodium intake to prevent and treat hypertension. It is necessary to develop the lifestyle modification program that may have beneficial effects on hypertension treatment.

• Journal of Medicine and Life Science
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• 제20권3호
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• pp.115-125
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• 2023

Arteriovenous fistula flow dysfunction is the leading cause of vascular access thrombosis and loss in patients undergoing hemodialysis. However, data regarding the influence of access flow rate measurements on the long-term outcomes of access are limited. This study aims to identify accesses at a high risk of thrombosis and loss among patients undergoing hemodialysis by measuring the access flow rate and exploring an optimal threshold value for predicting future access thrombosis. We enrolled 220 patients with arteriovenous fistula undergoing hemodialysis. The primary outcome was the occurrence of access thrombosis. Access flow rates were measured monthly using the ultrasound dilution method and were averaged using all measurements from patients with patent access. In patients experienced access thrombosis, those immediately before the thrombosis were selected. Using these data, we calculated the access flow rate threshold for thrombosis occurrence by analyzing the receiver operating characteristic curve, and the patients were divided into two groups according to whether access flow rates were higher or lower than 400 mL/min. During a median follow-up period of 3.1 years, 4,510 access flows were measured (median measurements per patient, 33 times; interquartile range, 11-54). A total of 65 access thromboses and 19 abandonments were observed. Access thrombosis and loss were higher in the lowflow group than in the high-flow group. This study revealed that low access flow rates are strongly associated with access thrombosis occurrence and subsequent loss of arteriovenous fistulas in patients undergoing hemodialysis.

• 대한전자공학회논문지SP
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• 제46권2호
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• pp.30-39
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• 2009

사구체 영역의 추출은 신장염 진단 자동화에 있어서 매우 중요한 역할을 하고있다. 그러나 사구체 영역과 타 영역과의 차이가 그다지 뚜렷하지 않고 동시에 표본화 과정과 영상취득과정에서 발생한 얼룩이 원영상에 존재하기 때문에 사구체 영역을 정확히 추출하는 일은 간단치 않다. 본 연구에서는 신장 사구체 영역의 추출에 관해서 유전적 알고리듬에 의한 새로운 방법을 제안한다. 우선, 표준편차 ${\sigma}=2.1$과 ${\sigma}=1.8$의 라플라시안-가우시안 필터를 사용해서 저해상도와 고해상도 영상을 획득한 후, 그 임계값을 0으로 설정하여 2치화 영상을 취득하며, 그런 다음, 저해상도 영상으로부터 경계에지를 추출한다. 사구체의 경계는 B-스플라인 폐곡선으로 표현한다. 이 저해상도 영상에 있어서 B-스플라인 폐곡선을 결정하는 파라메타는 유전적 알고리듬을 이용한 탐색에 의해 잡음과 경계선이 도중에서 끊어지는 것을 방지한다. 그 다음, 보다 정밀한 사구체의 경계 에지를 획득하기 위해 고해상도 영상으로부터 절점수를 8개, 16개 및 32개로 순차적으로 증가시켜 수정한다. 최종적으로 실제 영상에 적용함으로써 제안한 본 방법의 유효성을 확인하였다.