• Childhood Kidney Diseases
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• v.1 no.2
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• pp.101-108
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• 1997

Purpose : The clinical characteristics of renovascular hypertension (RVHT) in children were analyzed. Methods : Medical records of 16 children diagnosed as RVHT on the basis of angiography during Jan. '86 to Jun. 94 in our hospital were reviewed retrospectively. Results : The mean age at the onset was 8.5 yrs and the sex ratio(M:F) was 7:9. The causes of RVHT were Takayasu arteritis in 6, Moyamoya disease in 5, and fibromuscular dysplasia in 3 patients. Abdominal bruit was noted in 6 patients (38%). Peripheral renin activity was raised in all tested patients. Bilateral renal arterial involvemnent was found in 9 patients (56%). Captopril renal scans showed good correlation with angiographic findings. Five patients were treated with antihypertensives only, and blood pressure was controlled completely in 2 and incompletely in 3. Percutaneous transluminal angioplasty was performed in 10 patients with 50% of success rate. However, hypertension was recurred due to restenosis or accompaning aortic stenosis in 3 patients. Surgical treatment was performed in 4 patients, and the blood pressure was controlled partially in 1 and poorly in the remaining 3. Conclusions : Takayasu arteritis, Moyamoya disease and fibromuscular dysplasia are the major causes of childhood RVHT in our country. The diagnosis of RVHT in children should be based on a set of tests individually selected for case by case. For the low curability of the current treatment modalities available, RVHT in children should not be regarded as 'curable' so far. We expect, however, that the outcome will be improved by more extensive application of the newly developed surgical technique.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.161-167
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• 2007

Purpose : GFR(glomerular filtration rate) is a fundamental parameter in detecting renal impairment and predicts the progression of renal disease. Because serum creatinine has several disadvantages, serum cystatin C has been recently proposed as a new endogenous marker for GFR. We compared serum cystatin C with creatinine and creatinine clearance to investigate the clinical usefulness of cystatin C. Methods : We retrospectively analyzed 46 patients(60 case numbers) who had various renal diseases and classified them into 3 groups according to creatinine clearance(Group 1 : CrCl <40 mL/min/$1.73m^2$, Group 2 : CrCl 40-60 mL/min/$1.73m^2$, Group 3 CrCl >60 mL/min/$1.73m^2$). We measured serum creatinine, cystatin C and creatinine clearance and also analyzed the correlations among them. Results : Serum cystatin C and creatinine showed a similar correlation to creatinine clearance (r=0.685, r=0.640, respectively) and showed similar diagnostic accuracy in detecting decreased GFR(AUC, cystatin C 0.829 vs. creatinine 0.826, P=0.848). Serum cystatin C showed a greater sensitivity for detecting a decreased GFR than creatinine in Group 2 and 3(Group 1 : 100% vs. 100%, Group 2 : 70% vs. 35%, Group 3 : 46% vs. 15%). Conclusions : Serum cystatin C could be a useful endogenous marker for GFR and would be superior to serum creatinine in early detection of renal impairment in pediatric patients with renal diseases.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.327-333
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• 2012

Purpose: To analyze the correlation between dose volume histograms(DVH) based on organ outer wall contour and organ wall delineation for bladder and rectum, and to compare the doses to these organs with the absorbed doses at the bladder and rectum. Material and methods: Individual CT based brachytherapy treatment planning was performed in 13 patients with cervical cancer as part of a prospective comparative trial. The external contours and the organ walls were delineated for the bladder and rectum in order to compute the corresponding dose volume histograms. The minimum dose in 0.1 $cm^3$, 1 $cm^3$, 2 $cm^3$, 5 $cm^3$, 10 $cm^3$ volumes receiving the highest dose were compared with the absorbed dose at the rectum and bladder reference point. Results: The bladder and rectal doses derived from organ outer wall contour and computed for volumes of 2 $cm^3$, provided a good estimate for the doses computed for the organ wall contour only. This correspondence was no longer true when large volumes were considered. Conclusion: For clinical applications, when volumes smaller than 5 $cm^2$ are considered, the dose-volume histograms computed from external organ contours for the bladder and rectum can be used instead of dose -volume histograms computed for the organ walls only. External organ contours are indeed easier to obtain. The dose at the ICRU rectum reference point provides a good estimate of the rectal dose computed for volumes smaller than 2 $cm^2$ only for a midline position of the rectum. The ICRU bladder reference point provides a good estimate of the dose computed for the bladder wall only in cases of appropriate balloon position.

• Asia pacific journal of information systems
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• v.18 no.1
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• pp.79-96
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• 2008

One of the roles of the Semantic Web services is to execute dynamic intra-organizational services including the integration and interoperation of business processes. Since different organizations design their processes differently, the retrieval of similar semantic business processes is necessary in order to support inter-organizational collaborations. Most approaches for finding services that have certain features and support certain business processes have relied on some type of logical reasoning and exact matching. This paper presents our approach of using imprecise matching for expanding results from an exact matching engine to query the OWL(Web Ontology Language) MIT Process Handbook. MIT Process Handbook is an electronic repository of best-practice business processes. The Handbook is intended to help people: (1) redesigning organizational processes, (2) inventing new processes, and (3) sharing ideas about organizational practices. In order to use the MIT Process Handbook for process retrieval experiments, we had to export it into an OWL-based format. We model the Process Handbook meta-model in OWL and export the processes in the Handbook as instances of the meta-model. Next, we need to find a sizable number of queries and their corresponding correct answers in the Process Handbook. Many previous studies devised artificial dataset composed of randomly generated numbers without real meaning and used subjective ratings for correct answers and similarity values between processes. To generate a semantic-preserving test data set, we create 20 variants for each target process that are syntactically different but semantically equivalent using mutation operators. These variants represent the correct answers of the target process. We devise diverse similarity algorithms based on values of process attributes and structures of business processes. We use simple similarity algorithms for text retrieval such as TF-IDF and Levenshtein edit distance to devise our approaches, and utilize tree edit distance measure because semantic processes are appeared to have a graph structure. Also, we design similarity algorithms considering similarity of process structure such as part process, goal, and exception. Since we can identify relationships between semantic process and its subcomponents, this information can be utilized for calculating similarities between processes. Dice's coefficient and Jaccard similarity measures are utilized to calculate portion of overlaps between processes in diverse ways. We perform retrieval experiments to compare the performance of the devised similarity algorithms. We measure the retrieval performance in terms of precision, recall and F measure? the harmonic mean of precision and recall. The tree edit distance shows the poorest performance in terms of all measures. TF-IDF and the method incorporating TF-IDF measure and Levenshtein edit distance show better performances than other devised methods. These two measures are focused on similarity between name and descriptions of process. In addition, we calculate rank correlation coefficient, Kendall's tau b, between the number of process mutations and ranking of similarity values among the mutation sets. In this experiment, similarity measures based on process structure, such as Dice's, Jaccard, and derivatives of these measures, show greater coefficient than measures based on values of process attributes. However, the Lev-TFIDF-JaccardAll measure considering process structure and attributes' values together shows reasonably better performances in these two experiments. For retrieving semantic process, we can think that it's better to consider diverse aspects of process similarity such as process structure and values of process attributes. We generate semantic process data and its dataset for retrieval experiment from MIT Process Handbook repository. We suggest imprecise query algorithms that expand retrieval results from exact matching engine such as SPARQL, and compare the retrieval performances of the similarity algorithms. For the limitations and future work, we need to perform experiments with other dataset from other domain. And, since there are many similarity values from diverse measures, we may find better ways to identify relevant processes by applying these values simultaneously.

• Journal of Chest Surgery
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• v.36 no.1
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• pp.15-20
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• 2003

Myasthenia gravis is a rare autoimmune disease involving acetylcholine receptor and its autoantibody on neuromuscular junction. The methods of treatment are medical treatment and surgical thymectomy. In this paper we analyzed the result of thymectomy and the factors affecting the postoperative symptom improvement. Material and method : This study obtained medical records of 37 patients who received the thymectomy for myasthenia gravis from March 1986 to December 1998. Result Out of 37 cases, 21 cases(57%) showed improvement, of which 8 cases (50%) in the group of thymoma(n=16), and 13 cases (62%) in the group of thymic hyperplasia(n=21) showed the improvement of symptoms. Postoperative complications were respiratory insufficiency due to aggravation of symptoms after operation, including tracheal intubation for ventilator support in 9 cases, pneumonia in 3 cases, pneumothorax in 2 cases and left vocal cord palsy in 1 case. There was one postoperative mortality. The relation between postoperative improvement and sex(P=0.3222), age(P=0.7642), thymic pathologic variants,(P=0.4335) and classification of thymoma(P=0.20) showed no statistically significant correlation. However, the lower grade of preoperative symptoms can predict the lower grade of postoperative symptoms significantly(P=0.0032). Follow up study to 36 postoperative survivors was performed in October 2002 based on the out-patient records and call with patients. Out of 36 cases, 33 cases(91.7%) could be investigated and 3 cases could not. Mean follow up period was 83.2 months. Out of 33 cases, 25 cases(75.8%) showed symptomatic improvement, of which 8 cases(53.3%) in the group of thymoma(n=15) and 17 cases(94.4%) in the group of thymic hyperplasia(n=18) showed the improvement of$\boxUl$ symptoms. Conclusion : In myasthenia gravis, thymectomy showed the good improvement, and more important factor affecting the improvement of symptoms was the grdae of preoperative symptoms. Also midterm and long term follow up results showed good symptomatic improvement.

• The Korean Journal of Nuclear Medicine
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• v.35 no.4
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• pp.241-250
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• 2001

Purpose: Vasospasm is a complication of aneurysmal subarachnoid hemorrhage (aSAH). We assessed the role of acetazolamide-enhanced brain perfusion SPECT (ACZ-SPECT) with Tc-99m ECD for predicting the prognosis of patients with aSAH. Materials and methods: Two SPECT studios (baseline with 740 MBq and ACZ-SPECT with 1480 MBq) with image subtraction were performed in 21 patients with aSAH. All patients had brain CT and angiogram. Vasoreactivity on ACZ-SPECT, perfusion defect on baseline SPECT, and vasospasm on angiogram were correlated with Hunt-Hess grading, extent of SAH (unilateral or bilateral) on CT, and clinical outcome. Vasoreactivity was considered decreased when cerebral/cerebellar uptake ratio difference from baseline SPECT to ACZ-SPECT was greater than 2SD of normal control values. Results: Decreased vasoreactivity was observed in 38% (8/21), perfusion defect in 81% (17/21), and vasospasm in 38% (8/21). The preserved vasoreactivity group showed better outcome scale (92%, 12/13) and the decreased vasoreactivity group showed poorer outcome scale (62.5%, 5/8) (p=0.014). Extensive SAH was more frequently seen in the decreased vasoreactlvlty group (87.5%, 7/8) than in the preserved vasoreactivity group (30.7%, 4/13)(p=0.017). The perfusion defect and vasospasm did not show good correlation with outcome scale, extent of SAH, and Hunt-Hess grading (p=ns). Vasoreactivity represented the patient's outcome better than the vasospasm in all of the vasoreactivity/vasospasm-mismatched cases (6 cases). Conclusions: Our data show that decreased vasoreactivity on ACZ-SPECT does not always represent vasospastic condition. But patients with decreased vasoreactivity reveal poorer outcome than patients with angiographic vasospasm do. Therefore ACZ-SPECT is a valuable, noninvasive test for predicting the prognosis of patients with aSAH.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.49-56
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• 1999

Purpose: Heart to liver ratio on T1-201 per rectal scintigraphy (shunt index) is known to be useful in the assessment of portal systemic shunt. We assessed T1-201 uptake pattern and early liver/heart uptake rate of T1-201 and correlated with shunt index in patients with chronic active hepatitis (CAH) and liver cirrhosis (LC). Materials and Methods: Fifty eight patients with biopsy-proven chronic liver disease (35 with CAH, 23 with LC) underwent T1-201 per rectum scintigraphy after instillation of 18.5 MBq of T1-201 into the upper rectum. We evaluated hepatic uptake (type 1 : homogeneous, 2: inhomogeneous segmental, 3: inhomogeneous nonsegmental) and extrahepatic uptake of spleen, heart and kidney (grade 0: no uptake, 1: less than liver, 2: equal to liver, 3: greater than liver). We measured the early liver/heart uptake rate (the slope of the liver to heart uptake ratio for 10 min) and shunt index (heart to liver uptake ratio). T1-201 uptake pattern and early liver/heart uptake rate of T1-201 was correlated with the pathologic diagnosis and shunt index. Results: Hepatic uptake patterns of type 1 and 2 were dominant in CAH (CAH: 27/35, LC. 8/23), and type 3 in LC (CAH: 8/35, LC: 15/23)(p<0.005). The grades of extrahepatic uptake were higher in LC than in CAH (spleen: p<0.001, other soft tissue: p<0.005). The early liver/heart uptake rate of CAH ($0.110{\pm}0.111$) was significantly higher than that of LC ($0.014{\pm}0.090$)(p<0.001). The sensitivity and specificity of the early liver/heart uptake rate were 77.7% and 67.7% in differentiating LC from CAH. There was negative correlation between early liver/heart uptake rate and shunt index (r=-0.3347, p<0.01). Conclusion: Hepatic and extrahepatic uptake pattern and early liver/heart uptake rate on T1-201 per rectum scintigraphy are useful in the assessment of portal systemic shunt in patients with chronic liver disease.

• The Korean Journal of Nuclear Medicine
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• v.34 no.6
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• pp.456-464
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• 2000

Purpose: To evaluate the effect of acupuncture on regional cerebral blood flow (rCBF) at acupoints suggested by oriental medicine to be related to the treatment of cerebrovascular diseases. Materials and Methods: Rest/acupuncture-stimulation Tc-99m ECD brain SPECT using a same-dose subtraction method was performed on 54 normal volunteers (34 males, 20 females, age range from 18 to 62 years) using six paradigms: acupuncture at acupoints GV. 20, GV. 26, LI. 4, ST. 36 and SP. 6. In the control study, needle location was chosen on a non-meridian focus 1 cm posterior to the right fibular head. All images were spatially normalized, and the differences between rest and acupuncture stimulation were statistically analyzed using SPM$^{(R)}$ for Windows$^{(R)}$. Results: Acupuncture applied at acupoint GV. 20 increased rCBF in both the anterior frontal lobes, the right frontotemporal lobes, and the left anterior temporal lobe and the left cerebellar hemisphere. Acupuncture at GV 26 increased rCBF in the left prefrontal cortex. Acupuncture at LI. 4 increased rCBF in the left prefrontal and both the inferior frontal lobes, and the left anterior temporal lobe and the left cerebellar hemisphere. Acupuncture at ST. 36 increased rCBF in the left anterior temporal lobe, the right inferior frontal lobes, and the left cerebellum. Acupuncture at SP. 6 increased rCBF in the left inferior frontal and anterior temporal lobes. In the control stimulation, no significant rCBF increase was observed. Conclusion: The results demonstrated a correlation between stimulation at each acupoint with increase in rCBF to the corresponding brain areas.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.266-275
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• 1998

Purpose: We measured pulmonary epithelial permeability by $^{99m}Tc-DTPA$ radioaerosol clearance in patients with diabetes and correlated with the presence of microangiopathy to understand the pathophysiology of pulmonary microangiopathy and evaluate $^{99m}Tc-DTPA$ radioaerosol clearance as a diagnostic test to assess pulmonary microangiopathy. Materials and Methods: We performed $^{99m}Tc-DTPA$ radioaerosol scan in 10 normal subjects, 10 asymptomatic smokers, 20 diabetic patients without history of smoking (10 with microangiopathy, 10 without microangiopathy). $^{99m}Tc-DTPA$ clearance half-time ($T_{1/2}$) was calculated, then compared with the result of chest radiography and pulmonary function test. Results: Chest radiography and pulmonary function test were normal in all subjects. There were no significant difference of clinical or laboratory characteristics between these groups except age. The diabetic patients with microangiopathy were significantly older (p<0.05). The $T_{1/2}$ of normal subjects and asymptomatic smokers were significantly different ($65.2{\pm}23.7min$ vs $39.6{\pm}9.8min$, p<0.05). For diabetic patients with microangiopathy, the $T_{1/2}$ was $90.5{\pm}46.5min$ and significantly delayed when compared with those of normals and asymptomatic smokers (p<0.05). However, the $T_{1/2}$ of diabetic patients without microangiopathy, $70.0{\pm}12.7min$, was not significantly different from those of normals or asymptomatic smokers (p>0.05). No significant correlation was found between the $T_{1/2}$ and spirometric parameters including DLco, FVC, $FEV_1,\;FEV_1/FVC$ (%) and $FEF_{25-75%}$ in all subjects, and between the $T_{1/2}$ and duration of diabetes ;in diabetic patients. Conclusion: Eventhough the influence of age can't be excluded, delayed $^{99m}Tc-DTPA$ clearance half-time ($T_{1/2}$) in diabetic patients with microangiopathy indicates decreased pulmonary capillary permeability as one of the pathophysiologic results of pulmonary microangiopaththy. Further studies are needed in larger number of age matched control and diabetic patients to evaluate the diagnostic efficacy.

• The Korean Journal of Nuclear Medicine
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• v.38 no.1
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• pp.62-73
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• 2004

Purpose: The herpes simplex virus type 1 thymidine kinase gene(HSV1-tk) is an attractive candidate as a reporter gene in noninvasive reporter gene monitoring system. The HSV1-tk gene was chosen as a reporter gene, because it has been extensively studied, and there are appropriate reporter probes, substrates of HSV1-tk gene product, to apply for HSV1-tk gene imaging. We used radiolabeled 5-iodovinyl-2'-deoxyuridine (IVDU) and 5-iodovinyl-2'-fluoro-2'-deoxyuridine (IVFRU) as reporter probes for HSV1-tk gene monitoring system. Materials and Methods: We prepared HSV1-tk gene transduced Morris hepatoma cell line using retroviral vector, MOLTEN containing HSV1-tk gene. And we confirmed the HSV1-tk gene expression by Northern blotting and Western blotting. We compared in vitro uptakes of radioiodinated IVDU and IVFRU to monitor HSV1-tk gene expression in Morris hepatoma cell line (MCA) and HSV1-tk gene tranduced MCA (MCA-tk) cells until 480 minutes. We also peformed correlation analysis between percentage of HSV1-tk gene tranduced MCA cell % (MCA-tk%) and uptakes of radiolabeled IVDU or IVFRU. Results: MCA-tk cell expressed HSV1-tk mRNA and HSV1-TK protein. Two compounds showed minimal uptake in MCA, but increased uptake was observed in MCA-tk. IVDU showed 4-fold higher accumulation than IVFRU at 480 min in MCA-tk (p<0.01). Both IVDU and IVFRU uptake were linearly correlated ($R^2>0.96$) with increasing MCA-tk%. Conclusion: The radiolabeld IVDU and IVFRU showed higher specific accumulation in retrovirally HSV1-tk gene transfected Morris hepatoma cell line. Both IVDU and IVFRU could be used as good substrates for evaluation of HSV1-tk gene expression.