• The korean journal of orthodontics
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• v.27 no.6 s.65
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• pp.979-995
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• 1997

The purpose of this study was to identify the preventive and the progressive inhibitory effects of enamel demineralization with fluoride releasing light-and self-cured orthodontic sealants(FluoroBond), in vitro, under the polarizing light microscope and the scanning electon microscope. The polarizing light microscopic group was subdivided into seven groups(Group A-Group G). The scanning electron microscopic group was also subdivided into seven groups(Group A'-Goup G'). For polarizing light microscopic evaluation, longitudinal sections were made longitudinally by Maruto cutter(Maruto Co., Japan) and Maruto grinding machine(Maruto Co., Japan). Sections were examined and photographed by the polarizing light microscope(Olympus Optical Co., Japan) using crossed polars and with the enamel rod longitudinal axis oriented at $45^{\circ}$ to the extinction position. For scanning electron microscopic evaluation, the specimens were coated with a highly conducting layer of gold palladium in a model Hus-4 high-vacuum evaporator and examined in an ISI-100B scanning electron microcope operated at 20kV. The results of this study were as follows : 1. The mean depths of artificial carious lesions under a polarized light microscope were $Group\;A(5.08{\mu}m),\;Group\;B(47.82{\mu}m,\;Group\;C(8.42{\mu}m),\;Group\;D(7.20{\mu}m),\;Group\;E(85.41{\mu}m),\;Group\;F(60.38{\mu}m),\;Group\;G(60.13{\mu}m)$. 2. There were statistically significant differences in Group B compared with Group A, C, and D(p<0.05), and also, in Group I compared with Group F and Group G(p<0.05). 3. Light-and self-cured orthodontic sealants had the preventive effects of enamel demineralization. 4. Light-and self-cured orthodontic sealants had the progressive inhibitory effects of enamel demineralization. 5. The time progress of demineralizing agent had no influence on the samples of light-and self-cured orthodontic sealants under the scanning electron microscope. 6. There was no difference between the specimens of light-and self-cured orthodontic sealants both in the polarized light microscopic group and in the scanning electron microscopic group.

• The Korean Journal of Nuclear Medicine
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• v.39 no.6
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• pp.421-429
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• 2005

Purpose: It has been postulated that dopamine release in the striatum underlies the reinforcing properties of nicotine. Substantial evidence in the animal studies demonstrates that nicotine interacts with dopaminergic neuron and regulates the activation of the dopaminergic system. The aim of this study was to visualize the dopamine release by smoking in human brain using PET scan with $[^{11}C]raclopride$. Materials and Methods: Five male non-smokers or ex-smokers with an abstinence period longer than 1 year (mean age of $24.4{\pm}1.7$ years) were enrolled in this study $[^{11}C]raclopride$, a dopamine D2 receptor radioligand, was administrated with bolus-plus-constant infusion. Dynamic PET was performed during 120 minutes ($3{\times}20s,\;2{\times}60s,\;2{\times}120s,\;1{\times}180s\;and\;22{\times}300s$). following the 50 minute-scanning, subjects smoked a cigarette containing 1 mg of nicotine while in the scanner. Blood samples for the measurement of plasma nicotine level were collected at 0, 5, 10, 15, 20, 25, 30, 45, 60, and 90 minute after smoking. Regions for striatal structures were drawn on the coronal summed PET images guided with co-registered MRI. Binding potential, calculated as (striatal-cerebellar)/cerebellar activity, was measured under equilibrium condition at baseline and smoking session. Results: The mean decrease in binding potential of $[^{11}C]raclopride$ between the baseline and smoking in caudate head, anterior putamen and ventral striatum was 4.7%, 4.0% and 7.8%, respectively. This indicated the striatal dopamine release by smoking. Of these, the reduction in binding potential in the ventral striatum was significantly correlated with the cumulated plasma level of the nicotine (Spearman's rho=0.9, p=0.04). Conclusion: These data demonstrate that in vivo imaging with $[^{11}C]raclopride$ PET could measure nicotine-induced dopamine release in the human brain, which has a significant positive correlation with the amount or nicotine administered bt smoking.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.234-240
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• 2007

Purpose: In this study we propose a block-iterative method for reconstructing Compton scattered data. This study shows that the well-known expectation maximization (EM) approach along with its accelerated version based on the ordered subsets principle can be applied to the problem of image reconstruction for Compton camera. This study also compares several methods of constructing subsets for optimal performance of our algorithms. Materials and Methods: Three reconstruction algorithms were implemented; simple backprojection (SBP), EM, and ordered subset EM (OSEM). For OSEM, the projection data were grouped into subsets in a predefined order. Three different schemes for choosing nonoverlapping subsets were considered; scatter angle-based subsets, detector position-based subsets, and both scatter angle- and detector position-based subsets. EM and OSEM with 16 subsets were performed with 64 and 4 iterations, respectively. The performance of each algorithm was evaluated in terms of computation time and normalized mean-squared error. Results: Both EM and OSEM clearly outperformed SBP in all aspects of accuracy. The OSEM with 16 subsets and 4 iterations, which is equivalent to the standard EM with 64 iterations, was approximately 14 times faster in computation time than the standard EM. In OSEM, all of the three schemes for choosing subsets yielded similar results in computation time as well as normalized mean-squared error. Conclusion: Our results show that the OSEM algorithm, which have proven useful in emission tomography, can also be applied to the problem of image reconstruction for Compton camera. With properly chosen subset construction methods and moderate numbers of subsets, our OSEM algorithm significantly improves the computational efficiency while keeping the original quality of the standard EM reconstruction. The OSEM algorithm with scatter angle- and detector position-based subsets is most available.

• Applied Microscopy
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• v.30 no.2
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• pp.213-232
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• 2000

The development of the knee joint was studied by electron microscopy in human fetuses ranging from 20 mm to 260 mm crown-rump length ($7\sim30$ weeks of gestational age). The appearance of the primordium of the meniscus and cruciate ligament was conspicuous as the mesenchymal cells , preceeding that of joint space at 30 mm fetus. The primitive joint cavity was first seen in the interzone from the 40 mm fetus and its intermediate layer proceeded developing as a narrow cleft which was closely incorporated with two chondrogenic layers. Poorly differentiated mesenchymal cells of the meniscus at 40 mm fetus containing predominantly free ribosomes differentiated into fibroblasts at 60 mm fetus. By 100 mm fetus, the fibroblast in inner zone of the meniscus presented as oval profiles with a short cell processes, whereas middle and peripheral zones presented as elongated cells. Differentiation of the synovial membrane coincided with clarification of the joint cavity When dilatation of the synovial cavity occurred, the two types of synovial cells were identified at 60 mm fetus. By 100 mm fetus a majority of the intimal cells were B-type. B-type cells were clearly distinguishable from A-type cells by their content of extensive rough endoplasmic reticula and well developed Golgi complexes. In contrast, A-type cells had numerous filopodia, pinocytotic vesicles, lysosomes and large vacuoles. At 260 mm fetus the B-type cells were also a majority of intimal cells. At 260 mm fetus the inner zone of the meniscus was filled with parallel oriented fascicles of collagenous fibers and oval fibroblasts. The middle zone was constituted of parallel and radially arranged fibers and fibroblasts. The outer zone was populated by elongated fibroblasts encircled by crossed collagenous fibers with the blood vessels. At 30 mm fetus the fibroblasts of the cruciate ligament contained rough endoplasmic reticula and mitochondria. Collagen fibrils were noted within narrow cytoplasmic processes which were continued with the extracellular space. Collagen fibrils of ligament were filled in the bulk of extracellular space at 100 mm fetus. By $150\sim260mm$ fetus, the cruciate ligaments were constituted of longitudinally oriented bundle of collagen fibrils with irregular rows of round cells between.

• Economic and Environmental Geology
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• v.8 no.1
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• pp.1-23
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• 1975

The subject of this study deals with phase relations between stannite ($Cu_2FeSnS_4$) and sphalerite (${\beta}-ZnS$)/wurtzite (${\alpha}-ZnS$). The phase relations were systematically investigated from liquidus temperature to $400^{\circ}C$ under controlled conditions. ${\beta}-stannite$ (tetragonal) is stable up to $706{\pm}5^{\circ}C$, where it inverts to a high-temperature polymorph ${\alpha}-stannite$ (cubic) melting congruently at $867{\pm}5^{\circ}C$. Sphalerite (cubic, ${\beta}-ZnS$) inverts at $1013{\pm}3^{\circ}C$ to wurtzite, which is the hexagonal hightemperature polymorph of ZnS. Between ${\alpha}-stannite$ and sphalerite a complete solid solution series exists above approximately $870^{\circ}C$ up to solidus temperature. The melting temperature of ${\alpha}-stannite$ rises towards sphalerite and reaches a maximum at $1074{\pm}3^{\circ}C$, which is the peritectic with the composition of 91 wt. % sphalerite and 9 wt. % ${\alpha}-stannite$. At this temperature, wurtzite takes only 5wt. % ${\alpha}-stannite$ in solid solution which decreases with increasing temperature. The inverson temperature of ${\alpha}/{\beta}-stannite$ is lowered with increasing amounts of sphalerite in solid solution down to $614{\pm}7^{\circ}C$, which is the eutectoid with the composition of 13 wt. % sphalerite and 87 wt. % ${\alpha}-stannite$. Here, ${\beta}-stannite$ contains only 10wt. % sphalerite in solid solution. With decreasing temperature, the ranges of the solid solution on both sides of the system narrow. The phase relations in the above pure system changed due to the FeS impurities in the sphalerite solid solution. The eutectoid increased from $614{\pm}7^{\circ}C$ up to $695{\pm}5^{\circ}C$ (5 wt. % FeS) and $700{\pm}5^{\circ}C$ (10wt. % FeS), while the peritectic decreased from $1074{\pm}3^{\circ}C$ down to $1036{\pm}3^{\circ}C$ (wt. %FeS) and $987{\pm}3^{\circ}C$ (10wt. %FeS). A most notable change is the appearance of non-binary regions. An important feature is the combination of this study system with the experimental results reported by Sprinfer (1972). If a stannite-kesterite solid solution is used in the place of stannite as a bulk composition, the inversion temperature is lowered to less than $400^{\circ}C$ which belongs to temperatures of the hydrothermal region.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.260-265
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• 2011

Plantago asiatica L. (P. asiatica) has been used as one of the popular folk medicines in Asia for human health care practices. Various activities of P. asiatica have been reported, such as anti-oxidant, anti-glycation, anti-inflammatory and hepatoprotective activity. Therefore, the potential of P. asiatica to reduce oxidative stress has been studied in several ways for over 20 years, especially at liver and kidney. However no investigation has been reported revealing its protective effect on prostate. Method: Treatment of P. asiatica leaf ethanolic extract (PLE) (1 g/kg body weight (b.w.), 2 g/kg b.w., or 4 g/kg b.w.) were given separately to animals for pretreatment once per day for 7 days, and on the seventh day ferric nitrilotriacetate (Fe-NTA; 0.24 mmol Fe/kg b.w.), which is known as an oxidative stress-inducer at prostate, was administrated by i.p to negative control group. At the end of the study period, dissection was carried out for detecting the prostate protective effect of PLE. Result: Fe-NTA-treated animals produced reactive oxygen species (ROS) resulting in depletion of antioxidant biomaker, such as glutathione (GSH), glutathione reductase (GR), and glutathione s-transferase (GST) and increase of lipid peroxidation in prostate. However, PLE pretreatment resulted in an increase in the GSH, GST and GR levels concentration dependent manner and in an significant decrease in the levels of lipid peroxidation. Conclusion: Our data suggest that PLE may be effective in protecting oxidative stress-induced damage of prostate, and PLE may be an chemopreventive agent against Fe-NTA-mediated prostate oxidative damage.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.122-127
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• 2010

Purpose: The Xpress3.$cardiac^{TM}$ which is a kind of wide beam reconstruction (WBR) method developed by UltraSPECT (Haifa, Israel) enables the acquisition of at quarter time while maintaining image quality. The purpose of this study is to investigate the usefulness of WBR method for decreasing scan times and to compare to it with filtered back projection (FBP), which is the method routinely used. Materials and Methods: Phantom and clinical studies were performed. The anthropomorphic torso phantom was made on an equality with counts from patient's body. The Tl-201 concentrations in the compartments were 74 kBq (2 ${\mu}Ci$)/cc in myocardium, 11.1 kBq (0.3 ${\mu}Ci$)/cc in soft tissue, and 2.59 kBq (0.07 ${\mu}Ci$)/cc in lung. The non-gated Tl-201 myocardial perfusion SPECT data were acquired with the phantom. The former study was scanned for 50 seconds per frame with FBP method, and the latter study was acquired for 13 seconds per frame with WBR method. Using the Xeleris ver. 2.0551, full width at half maximum (FWHM) and average image contrast were compared. In clinical studies, we analyzed the 30 patients who were examined by Tl-201 gated myocardial perfusion SPECT in department of nuclear medicine at Asan Medical Center from January to April 2010. The patients were imaged at full time (50 second per frame) with FBP algorithm and again quarter-time (13 second per frame) with the WBR algorithm. Using the 4D MSPECT (4DM), Quantitative Perfusion SPECT (QPS), and Quantitative Gated SPECT (QGS) software, the summed stress score (SSS), summed rest score (SRS), summed difference score, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were analyzed for their correlations and statistical comparison by paired t-test. Results: As a result of the phantom study, the WBR method improved FWHM more than about 30% compared with FBP method (WBR data 5.47 mm, FBP data 7.07 mm). And the WBR method's average image contrast was also higher than FBP method's. However, in result of quantitative indices, SSS, SDS, SRS, EDV, ESV, EF, there were statistically significant differences from WBR and FBP(p<0.01). In the correlation of SSS, SDS, SRS, there were significant differences for WBR and FBP (0.18, 0.34, 0.08). But EDV, ESV, EF showed good correlation with WBR and FBP (0.88, 0.89, 0.71). Conclusion: From phantom study results, we confirmed that the WBR method reduces an acquisition time while improving an image quality compared with FBP method. However, we should consider significant differences in quantitative indices. And it needs to take an evaluation test to apply clinical study to find a cause of differences out between phantom and clinical results.

• Childhood Kidney Diseases
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• v.3 no.2
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• pp.123-129
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• 1999

Purpose: Acute poststreptococcal glomerulonephritis(APSGN) is a renal disease which is characterized by glomerular proliferation and inflammatory changes due to immune reaction. Although the 95% of patients with APSGN seems to recover fully and present as benign course, the remaining patients show poor prognosis. Therefore comparative retrograde study between APSGN with and without nephrotic syndrome was done to find out the any prognostic indicator to predict the outcome in patients with APSGN. Methods: We had retrospectively analyzed seventy-one patients who were diagnosed as APSGN clinically from Mar.1989 to Feb.1999 in Yonsei university medical center. Sixty-four of the patients was APSGN without nephrotic syndrome(Group A) and seven patients were in APSGN with nephrotic syndrome(Group B). Results: Patients who were diagnosed as APSGN with nephrotic syndrome were seven(9.9%) out of seventy-one. In the comparative study, sex ratio was 1:1 in group A and 1.9: 1 in group B, onset mean age was $8.9{\pm}2.6$ in group A and $8.8{\pm}2.6$ in group B. Following clinical profiles were compared but there were no significant difference between these two groups: WBC count($9413{\pm}2964\;vs\;9368{\pm}2650(/mm^3)$), hemoglobin($10.6{\pm}1.2\;vs\;10.0{\pm}0.9(gm/dL)$), ASO($746.1{\pm}640.7\;vs\;614.9{\pm}475.9(IU/ml)$), $C_3(20.1{\pm}17.0\;vs\;16.9{\pm}13.1(mg/dL)$), $C_4(22.8{\pm}9.5\;vs\;22.6{\pm}6.9(mg/dL)$), BUN($25.8{\pm}26.1\;vs\;28.1{\pm}14.5(mg/dL)$), creatinin($0.8{\pm}0.3\;vs\;0.8{\pm}0.3(mg/dL)$), $C_{cr}(80.6{\pm}28.8{\pm}62.4{\pm}31.4(ml/min/1.73\;m^2$)), the duration of edma, gross hematuria, and hypertension. However, we found that there were a significant difference in the duration of proteinuria($1.95{\pm}2.27\;vs\;13.3{\pm}21.1(months)$)(P<0.05), decreased $C_3$ duration($1.9{\pm}2.9\;vs\;7.3{\pm}5.0(weeks)$)(P<0.05) and especially it was proloned according to the amount of early urine protein excretion. Conclusion: Our study showed markedly prolonged duration of proteinuria and decreased $C_3$ duration in patients with APSGN with nephrotic syndrome. We were not able to find the definite prognostic factor that will guide the outcome of patients with APSGN accompaning nephrotic syndrome, but above findings seemed to represent as a relative indication of the outcome of the disease. All patients recovered completely and we did not experience any cases that progressed into the renal failure.

• Childhood Kidney Diseases
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• v.3 no.2
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• pp.161-169
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• 1999

Purpose : The urinary mass screening program for the detection of proteinuria in school aged population has been performed in Seoul since 1981. Systematic evaluation in corporation with the Seoul School Health Center for students with proteinuria identified in the mass screening has been performed from 1987. The results of urinary mass screening up to 1994 was reported. I report here the results of urinary mass screening from 1995 to 1997 and compare them with previous results and attempt to reveal the significance of urinary mass screening. Objects and Methods : In the 3-year period between 1995 and 1997, annually about 460,000 students comprising 3 different age groups; 5th grade of elementary school, 2nd grade of middle school and 2nd grade of high school were chosen, corresponding to the approximate ages of 11, 14, and 17 years, respectively. These subjects accounted for 26% of total school aged children in Seoul. The screening program was carried out in 3 steps. The 1st test was performed with dipstick at school and the 2nd at the Seoul School Health Center. Those students who showed proteinuria in the 1st and 2nd tests were referred to the hospital. Laboratory examinations including renal biopsies were performed to those students with pathologic proteinuria to clarify the incipient renal diseases. Results : 1) The prevalence of asymptomatic proteinuria was 0.28% in the 1st test. It peaked at the group of 14 years old as 0.34%, compared with 0.26% at the group of 11 years old and 0.24% at the group of 17 years old. It reached to 0.26% in male and 0.30% in female. 2) 25 percent of those having proteinuria at the first test were positive at the second test. 3) The proportion of patients with proteinuria by 3rd test were as follows; 25% of transient proteinuria, 55% of orthostatic proteinuria, 6% of constant proteinuria, 12% of proteinuria with hematuria, and 2% of transient proteinuria with isolated hematuria. Pathologic proteinuria were totaled as 20%. The prevalence of renal diseases among the age group of 7-18 years old was estimated to be 1.4 per 10,000. 4) Renal biopsy performed on 38 children with proteinuria at the third test revealed IgA nephropathy in 17(44%), focal segmental glomerusclerosis in 5(13%), minimal change disease in 4(11%), membranoproliferative glomeronephritis in 3(8%), $Henoch-Sch\"{o}nlein$ purpura nephritis in 3(8%), and others in 6(16%). Therefore, the prevalence of IgA nephropathy among the age group of 7-18 years old was estimated to be 0.64 per 10,000. 5) The prevalence of chronic renal failure was estimated to be 5.7 per 1 million of 7 to 18 years age group. Conclusions : 1) The prevalence of proteinuria in the first screening test was 0.28% and finally only 5% of them showed the pathologic proteinuria at the third test. 2) The prevalence of IgA nephropathy and chronic renal failure were 0.63 per 10,000 and 5.7 per 1 million, respectively among school-aged children in Seoul.

• Childhood Kidney Diseases
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• v.3 no.2
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• pp.170-179
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• 1999

Purpose: To evaluate whether or not sodium restriction had its own beneficial effect and increased the efficiency of the anti-hypertensive drugs on the progression of renal failure. Methods: We studied using the excision remnant kidney model. Treatment groups were as follows: 5/6 nephrectomy and a 0.49% (normal-high) sodium diet (NN); 5/6 nephrectomy and a 0.25% (normal-low) sodium diet (LN); 5/6 nephrectomy, a 0.49% sodium diet and enalapril (NNE); 5/6 nephrectomy, a 0.49% sodium diet and nicardipine (NNN); 5/6 nephrectomy, a 0.25% sodium diet and enalapril (LNE); 5/6 nephrectomy, a 0.25% sodium diet and nicardipine (LNN). Both diets were isocaloric and had the same content of protein, phosphorus and calcium. Proteinuria, remnant kidney weight, mesangial expansion scores, and glomerular volume were assessed. Results: Blood pressure tended to be lower in LN compared to NN (P<0.05). NN developed progressive hypertension. LNE, LU, NNE, and NNN reduced blood pressure. LNE, LNN, NNE, NNN, and LN had significantly less proteinuria than NN at 16 weeks (P<0.05). At 24 weeks, LN developed proteinuria (82 mg/day), which were lessened in LNE (54 mg/day) and not lessened in LNN (76 mg/day). Mesangial expansion scores were significantly less in LN rats compared to those in NN rats. Glomerular volumes at 24 weeks in LN rats were significantly less compared to those at 16 weeks in NN rats. Mesangial expansion scores and glomerular volumes at 4, weeks, 12 weeks, and 24 weeks were not different among LN, LNE, and LNN groups. Conclusion: Dietary salt restriction lessens renal damage, at least in part, by inhibiting compensatory renal growth and reducing blood pressure. Enalapril was particularly successful in reducing proteinuria and glomerular injury when combined with dietary salt restriction.