• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.199-210
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• 2003

Tooth movement is the result of bone metabolism in the periodontium, where various cytokines take important roles. Interleukin-6(II-6) and nitrous oxide (NO) were reported to be secreted from osteoblasts in the process of bone resorption. The mechanism of the process has not been clearly understood, but the activation of mitogen-activated protein kinase (MAPK) was known to be an important process in the release of the inflammatory cytotines in macrophages. In this regard, to prove the role of MAPK in the release of IL-6 and NO in MC3T3E-1 osteoblasts, Northern blot analysis, Western blot analysis and immune complex kinase assay were used. As a result, the treatment of MC3T3E-1 osteoblast cultures with combined $interferon-\gamma(IFN-\gamma)$, lipopolysaccharide (LPS) and tumor necrosis $factor-\alpha(TNF-\alpha)$ induces expressions of inducible nitric oxide synthase (iNOS) and IL-6, resulting in sustained releases of large amounts of NO and IL-6. However, $IFN-\gamma,\;LPS,\;and\;TNF-\alpha$ individually induce a non-detectable or small amount of NO and IL-6 in MC3T3E-1 osteoblasts. The role of MAPK activation in the early intracellular signal transduction involved in iNOS and IL-6 transcription in the combined agents-stimulated osteoblasts has been investigated. The p38 MAPK pathway is specifically involved in the combined agents-induced NO and IL-6 release, since NO and IL-6 release in the presence of a specific inhibitor of p38 MAPK, 4-(4-fluorophenyl)-2-(4-metylsulfinylphenyl)-5-(4-metylsulfinylphenyl)-5-(4-pyridyl)imidazole) (SB203580), were significantly diminished. In contrast, PD98059, a specific inhibitor of MEK1, had no effect on NO and IL-6 release. Northern blot analysis showed that the p3a MAPK pathway controlled the iNOS and IL-6 transcription level. These data suggest that p38 MAPK play an important role in the secretion of NO and IL-6 in $LPS/IFN{\gamma}-or\;TNF-\gamma-treated\;MC3T3E-1$ osteoblasts.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1009-1016
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• 2018

Purpose: To assess the effect on axial elongation and associated factors between spectacles and of orthokeratology lens (OK) wearing in children with mild to moderate myopia. Methods: A total of one hundred subjects, ranging in age from 6 to 13 years, and with mild to moderate myopia no more than -4.50 diopters in spherical equivalent, visited our clinic from 2013 to 2015. The OK group (75 eyes) and the spectacles group (64 eyes) were compared and analyzed on the axial elongation and associated factors. Results: In the OK group, axial length was elongated in 1 year period with a mean increase of $0.24{\pm}0.29mm$. In spectacles group, axial length was elongated in 1 year period with a mean increase of $0.42{\pm}0.20mm$. The statistically significant suppression of axial elongation was observed in OK group compared to the spectacles group (Mann-Whitney U test, p < 0.05). For OK group, the age of starting OK (Pearson's correlation, r = -0.481, p < 0.05) was the only influencing factor on axial elongation, which had negative correlation with axial elongation. In spectacles group, the age of starting spectacles had negative correlation with axial elongation (Pearson's correlation, r = -0.462, p < 0.05) and baseline spherical equivalent, spherical diopter, cylindrical diopter from manifest refraction had positive correlation with axial elongation. Comparison of axial elongation in orthokeratology lens group and spectacles group by age groups (6 to 9 years [28 eyes], 9 to 13 years [47 eyes]), 9 to 13 years of orthokeratology lens group had the stronger suppression of axial elongation (Mann-Whitney U test, p < 0.05). Conclusions: The OK effectively suppresses axial elongation compared to the spectacles. Although the patients are in age from 9 to 13 years, the axial elongation was effectively suppressed.

• Journal of Periodontal and Implant Science
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• v.24 no.2
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• pp.219-237
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• 1994

The ultimate goal of clinical periodontal therapy is to achieve regeneration of a healthy connective tissue reattachment. Conventional therapy including scaling, root planing, gingival curettage, gingivectomy and flap procedures of various types results primarily in repair rather than regeneration of the periodontium. In order for periodontal regeneration to occur, progenitor periodontal ligament cells must migrate to the denuded root surface, attach to it, proliferate and mature into an organized and functional fibrous attachment apparatus. Polypeptide growth factors belong to a class of potent biologic mediators which regulate cell differentiation, proliferation, migration and metabolism. Insulin-like growth factor-I (IGF- I ) of these factors appear to have an important role in periodontal wound healing and bone formation. The purpose of this study is to evaluate the effects of IGF- I on the periodontal ligament cells to use as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were obtained from periodontal tissue explants culture of the first premolar tooth extracted for the orthodontic treatment. Cells were cultured in Dulbecco's modified Eagle medium(DMEM) with 10% fetal bovine serum. Fourth to seventh passage cells were plated in 24 well tissue culture plates and medium changed to serum-free medium prior to addition of growth factors. Cell proliferation was measured by the incorporation of $[^3H]-thymidine$ into DNA, Protein synthesis was determined by measurement of $[^3H]-proline$ incorporation into collagenase-digestible protein(CDP) and noncollagenous protein(NCP) according to the method of Peterkofsky and Diegelmann (1971), And alkaline phosphatase activity was measured as one parameter of osteoblastic differentiation. The results were as follows : The DNA synthetic activity was increased in a dose-dependent manner with IGF- I except for 0.1ng/ml concentration of IGF- I At the concentration of 10, 100ng/ml, IGF- I significantly increased the DNA synthetic activity(P<0.05) The total protein, collagen and noncollagen synthesis was increased in a dose-dependent manner with IGF- I except for 0.1ng/ml concentration of IGF- I. At the concentration of 1, 10, 100ng/ml, IGF- I significantly increased the total protein, collagen and noncollagen synthesis activity(P<0.95, P<0.001). The % of collagen was not effected according to the concentration of IGF- I. The alkaline phosphatase activity was increased in a dose-, time-dependent manner with IGF- I (10, 100ng/ml). In conclusions, the present study shows that IGF- I has a potentiality to enhance the DNA synthesis of periodontal ligament cells with including the increase of the total protein and collagen synthetic activity. The use of IGF- I to mediate biological stimulation of periodontal ligament cells shows promise for future therapeutic applications.

• Radiation Oncology Journal
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• v.28 no.1
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• pp.50-56
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• 2010

Purpose: We report the results of an external audit on the absorbed dose of radiotherapy beams independently performed by third parties. For this effort, we developed a method to measure the absorbed dose to water in an easy and convenient setup of solid water phantom. Materials and Methods: In 2008, 12 radiotherapy centers voluntarily participated in the external auditing program and 47 beams of X-ray and electron were independently calibrated by the third party’s American Association of Physicists in Medicine (AAPM) task group (TG)-51 protocol. Even though the AAPM TG-51 protocol recommended the use of water, water as a phantom has a few disadvantages, especially in a busy clinic. Instead, we used solid water phantom due to its reproducibility and convenience in terms of setup and transport. Dose conversion factors between solid water and water were determined for photon and electron beams of various energies by using a scaling method and experimental measurements. Results: Most of the beams (74%) were within ${\pm}2%$ of the deviation from the third party's protocol. However, two of 20 X-ray beams and three of 27 electron beams were out of the tolerance (${\pm}3%$), including two beams with a >10% deviation. X-ray beams of higher than 6 MV had no conversion factors, while a 6 MV absorbed dose to a solid water phantom was 0.4% less than the dose to water. The electron dose conversion factors between the solid water phantom and water were determined: The higher the electron energy, the less is the conversion factor. The total uncertainty of the TG-51 protocol measurement using a solid water phantom was determined to be ${\pm}1.5%$. Conclusion: The developed method was successfully applied for the external auditing program, which could be evolved into a credential program of multi-institutional clinical trials. This dosimetry saved time for measuring doses as well as decreased the uncertainty of measurement possibly resulting from the reference setup in water.

• Journal of Chest Surgery
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• v.38 no.4 s.249
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• pp.277-283
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• 2005

Arterial oxygen saturation $(SaO_2)$ instability frequently takes place after systemic-pulmonary shunt without shunt occlusion. We analyzed actual incidence and risk factors for $SaO_2$ instability after shunt operations, and possible mechanisms were speculated on. Material and Method: Ninety three patients, who underwent modified Blalock-Taussig shunt from January 1996 to December 2000, were enrolled in this study. Adequacy of shunt was verified in all patients, either by ensuing one ventricle or biventricular repair later on or by appropriate pulmonary artery growth on postoperative angiogram. Age, body weight, hemoglobin level at operation were 3 day to 36 years (median: 1.8 months), 2.5kg to 51kg (median: 4.1kg) and $10.7\~24.3$ gm/dL (median: 15.2 gm/dL) respectively. Preoperative diagnoses were functional single ventricle with pulmonary stenosis or atresia in 39, tetralogy of Fallot in 38 and pulmonary atresia with intact ventricular septum in 16. Pulmonary blood flow (PBF) was maintained pre-operatively by patent ductus or previous shunt in 64 and by forward flow through stenotic right ventricular outflow tract (RVOT) in 29. $SaO_2$ instability was defined as $SaO_2$ less than $50\%$ for more than 1 hour with neither anatomic obstruction of shunt nor respiratory problem. Result: 10 patients $(10.7\%)$ showed $SaO_2$ instability after shunt operation. After shunt occlusion was ruled out by echocardiogram, they received measures to lower pulmonary vascular resistance (PVR), which worked within a few hours in all patients. Risk factors for $SaO_2$ instability included older age at operation (p=0.039), lower preoperative $SaO_2$ (p=0.0001) and emergency operation (p=0.001). PBF through stenotic RVOT showed marginal statistical significance (p=0.065). Conclusion: $SaO_2$ instability occurs frequently after shunt operation, especially in patients with severe hypoxia pre-operatively or unstable clinical condition necessitating emergency operation. Temporary elevation of pulmonary vascular resistance is a possible mechanism in this specific clinical setting.

• Journal of Chest Surgery
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• v.37 no.6
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• pp.524-529
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• 2004

Background: Since the Nuss procedure for the correction of pectus excavatum is in its early stage, there have been problems that need to be solved. We examined complications in a single-institute experience of the Nuss technique in order to develop possible solutions to prevent them. Material and Method: 335 consecutive patients, who underwent the modified Nuss procedure between August 1999 and October 2002, were studied retrospectively. Median age was 8 years (range 1 to 46). 264 patients (78.8%) were in pediatric group (age$\leq$15) and 71 patients (21.2%) were in adult group (age> 15). 193 patients (57.6%) had symmetric and 142 patients (42.4%) had asymmetric pectus configurations. Risk factors predicting postoperative complications were analyzed using multi-variate logistic regression. Result: Postoperative complication rates were 18.9% (61/335) in total patients. Frequent complications were pneumothorax 24 (7.5%), bar displacement 11 (3.4%), and wound seroma 10 (3.1%) in order. Early complications (within a month, 49 cases, 15.2%) were pneumothorax (n=23, 6.9%), wound seroma (n=12, 3.6%), and bar displacement (n=8, 2.4%). Late complications (after a month, 12 cases, 3.7%) were pericarditis and pericardial effusion (n=5, 1.5%), bar displacement (n=4, 1.2%), and hemothorax (n=3, 0.9%). Techniques were modified to prevent complications especially in bar shaping and fixation, which led to decrease complication rate in later experience (Operation Date 1: 15/51 (29.4%) vs Operation Date 2: 34/284 (12.0%), p=0.004). Grand Canyon type (eccentric long canal type) showed higher complication rate than other types (GC type: 12/30(40%) vs Others: 37/305 (12.1%), p<0.001). Major risk factors are severity of pectus (OR=2.88, p=0.038), Grand Canyon type (OR=2.82, p=0.044), and Op. Date 1 (OR=4.05, p=0.001). Conclusion: Major complications were related to severe eccentric type of pectus configuration (Grand Canyon type) and lack of surgeon's experience (Op. Date 1). Com-plication rate was reduced with accumulation of experience and advancement of surgical techniques. The Nuss procedure can be performed at a low risk of complications with our current technique.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.108-118
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• 1999

Background: To evaluate the risk factor and long-term result of arterial switch operation , a retrospective study was done. Material and Method: A retrospective analysis was done to evaluate the early and long-term results on 58 patients who underwent an arterial switch operation(ASO) for transposition of the great arteries(TGA) with intact ventricular septum, between January 1988 and December 1996. Beforesurgery, 36 patients(62.1%) underwent balloon atrial septostomy, 32 patients(51.7%) received PGE1 infusion, and preparatory banding of pulmonary artery was performed on 6 patients(mean LV/RV pressure ratio 0.53$\pm$0.11). Result: The age at operation ranged from 1 to 137 days(mean 24$\pm$26 days) and the weights ranged from 1.8 to 6.8 kg (mean 3.5$\pm$0.8 kg). There were 14 early deaths(24.1%), but of the last 24 patients operated on since 1994, there were only 2 early deaths(8.3%). In the risk factor analysis, the date of operation was the only risk factor for early death(p-value < 0.01). Eight of the 14 early deaths were due to acute myocardial failure(mainly inadequate coronary blood flow). The length of follow-up ranged from 2 months to 8 years, average of 36$\pm$27 months. The follow-up included sequential noninvasive evaluations and 21 catheterizations and angiographic studies performed 5 to 32 months postoperatively with particular attention to the great vessel and coronary anastomosis, ventricular function, valvular competence, and cardiac rhythm. There were 5 late deaths(11.4%), one of thesedeaths was related to the late coronary problems, two to aspiration, one to uncontrolled chronic mediastinitis, and one to progressive aortic insufficiency and heart failure. The most frequent postoperative hemodynamic abnormality was supravalvular stenosis and the degree of pulmonary or aortic obstruction had slowly progressed in some cases, however there were no children who had to undergo a reoperation for supravalvular pulmonary or aortic stenosis. Aortic regurgitation was identified in 9 patients, which was mild in 7 and moderate in 2 and had progressed in some cases. Two patients who had an unremarkable perioperative course were identified as having coronary artery obstructions. The other late survivors were in good condition, were in sinus rhythm, and had normal LV functions. Actuarial survival rate at 8 years was 68.8%. Conclusion: We concluded that anatomic correction will be established as the optimal approach to the TGA with intact ventricular septum, though further long-term evaluations are needed.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.169-178
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• 2011

BACKGROUND: This study aimed to estimate the measurement uncertainty associated with determination of cadmium and lead from tomato paste by ICP/MS. The sources of measurement uncertainty (i.e. sample weight, final volume, standard weight, purity, molecular weight, working standard solution, calibration curve, recovery and repeatability) in associated with the analysis of cadmium and lead were evaluated. METHODS AND RESULTS: The guide to the expression of uncertainty was used for the GUM (Guide to the expression of Uncertainty in Measurement) and Draft EURACHEM/CITAC (EURACHEM: A network of organization for analytical chemistry in Europe/Co-Operation on International Traceability in Analytical Chemistry) Guide with mathematical calculation and statistical analysis. The uncertainty components were evaluated by either Type A or Type B methods and the combined standard uncertainty were calculated by statistical analysis using several factors. Expected uncertainty of cadmium and lead was $0.106{\pm}0.015$ mg/kg (k=2.09) and $0.302{\pm}0.029$ mg/kg (k=2.16), on basis of 95% confidence of Certified Reference Material (CRM) which was within certification range of $0.112{\pm}0.007$ mg/kg for cadmium (k=2.03) and $0.316{\pm}0.021$ mg/kg for lead (k=2.01), respectively. CONCLUSION(s): The most influential components in the uncertainty of heavy metals analysis were confirmed as recovery, standard calibration curve and standard solution were identified as the most influential components causing uncertainty of heavy metal analysis. Therefore, more careful consideration is required in these steps to reduce uncertainty of heavy metals analysis in tomato paste.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.701-710
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• 2004

Uncertainty was quantified to evaluate calcium determination result in infant formula with AAS (Atomic Absorption Spectrometry) and ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Uncertainty sources in measurand, such as sample weight, final volume of sample, sample dilution and the instrumental result were identified and used as parameters for combined standard uncertainty based on the GUM (Guide to the expression of uncertainty in measurement) and Draft EURACHEM/CITAC Guide. Uncertainty components of each sources in measurand were identified as resolution, reproducibility and stability of chemical balance, standard material purity, standard material molecular weight, standard solution concentration, standard solution dilution factor, sample dilution factor, calibration curve, recovery, instrumental precision, reproducibility, and stability, Each uncertainty components were evaluated by uncertainty types and included to calculate combined uncertainty. The kinds of uncertainty sources and components in the analytical method by AAS and ICP-AES were same except sample dilution factor for AAS. The analytical results and combined standard uncertainties of calcium content were estimated within the certification range $(367{\pm}20\;mg/100g)$ of CRM (Certified Reference Material) and were not significantly different between method by AAS followed by ashing and method by ICP-AES followed by acid digestion as $359.52{\pm}23.61\;mg/100g\;and\;354.75{\pm}16.16\;mg/100g$, respectively. Identifying uncertainty sources related with precision, repeatability, stability, and maintaining proper instrumental conditions as well as personal proficiency was needed to reduce analytical error.

• Journal of Chest Surgery
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• v.37 no.5
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• pp.410-415
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• 2004

Background: In the operation for coronary artery stenosis, the procedures for mitral regurgitation are restricted to cases of more than moderate mitral regurgitation or for the lesions in leaflets. This is based on the belief that the less than mild regurgitation are a form of reversible change results from ischemia with coronary artery stenosis. We studied the changes and prognostic factors of mitral regurgitation in patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone. Material and Method: We reviewed the medical records of 90 patients with coronary artery stenosis and mitral regurgitation who underwent coronary artery bypass surgery alone by a single surgeon from Jan. 1995 to Dec. 2002, We grouped the patients according to the postoperative changes of mitral regurgitation, and then we statistically compared the findings of echocardiogram between preoperative and last follow up. Result: There were 24 cases with progression of mitral regurgitation, 12 cases without changes, 54 cases with improvements of mitral regurgitation in total 90 patients. The bypass to LAD was proven as the significant prognostic factor of mitral regurgitation. The preoperative end diastolic left ventricular volume index were higher in aggravated group with 105.38$\pm$38.89 $m\ell$ compared to 71.75$\pm$28,45 $m\ell$ in improvement group, and 84.00$\pm$11.66 $m\ell$ in no change group. The grade of preoperative mitral regurgitation did not show significant differences among the groups. Conclusion: The mitral regurgitation in patient with coronary artery stenosis can be improved after the coronary artery bypass surgery alone. However, the expectation of improvements based on the degree of preparative mitral regurgitation can not be justified, therefore, the procedures for mitral regurgitation should be aggressively considered even in the cases of mild mitral regurgitation. Also, further study should be performed to identify the exact prognostic factors of mitral regurgitation including the left ventricular volume index, and whether the left anterior descending artery has been bypassed.