• Korean Journal of Head & Neck Oncology
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• v.9 no.1
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• pp.3-9
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• 1993

The benficial effects for perfusion in the preservation of free flaps have been controversial in the clinical and experimental field until now. This study was undertaken to observe the effect of UW solution. a recently developed. high molecular weight. organ perfusion solution. for protection of ischemic injury in normothermic free myocutaneous flaps. Forty rabbits were used in this sutdy. A 1x2x1cm sized gastrocnemius myocutaneous flap based on the feeding vessel from common femoral artery was made. The author set up the ischemic time for 12 hours in these flaps. The flap was washed out with normal saline(control grop, n=10), urokinase(comparative group I, n=10), UW solution before ischemic time(comparative group II, n=10) and UW solution before ischemic time and pentoxifylline before reperfusion(comparative group III, n=10). Afterthen, reperfusion was made for 12 hours. After this procedure, we checked the degree of ischemia and necrosis of myocutaneous flap by gross finding, electrical stimulation test of muscle, triphenyltetrazolium chloride staining and wet/dry weight ratio. The degree of necrosis of comparative group II and III were lesser than control and urokinase group in gross finding(p<0.05). In the electrical stimulation test of muscle, there was no statistical difference between control($1.76{\pm}1.01$) and urokinase($2.36{\pm}\1.02$) group however the muscular power of comparative group II($3.54{\pm}0.93$) and III($3.49{\pm}1.37gm/mm^2$) demonstrated significantly higher than control group(p<0.05). The ischemic findings were found in seven cases of control group and three cases of urokinase group but there were no ischemic findings in comparative group II and III in TIC stain(p<0.05). In the wet/dry weight ratio of flaps in order to evaluate the tissue edema. there was no statistical difference between control($4.55{\pm}0.29$) and III($3.75{\pm}0.48$) were scored significantly lesser than control and urokinase group (p<0.05). These results suggest that perfusion washout with UW solution improves the viability of normothermic free myocutaneous flap by inhibition of cellular swelling.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.259-265
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• 2010

Purpose: This study was aimed to evaluate the effect of different sizes of $\beta$-TCP/ HA particles on vertical bone augmentation using titanium mesh in the cranium of rabbits. Materials and methods: Six white rabbits weighing 5kg were used. Four circular grooves of 6mm diameter were made by trephine, and five small holes were drilled in the inner surface of each circular gooves. Different sizes of grafts (small 0.3 - 0.5 mm, medium 0.5 - 1.0, large 1.0 - 2.0 mm) were placed respectively in the experimental groups. Titanium mesh (height 3 mm, width 6 mm) was placed. After 8weeks healing period, the rabbits were euthanized, and the specimens were prepared for histological findings. New bone formation and remaining graft area were measured to calculate the ratio of areas occupying the inner space of titanium mesh. Mann-Whitney U-test and Wilcoxon signed rank-test were used for statistical analysis ($\alpha$ = .05). Results: The experimental groups with $\beta$-TCP/HA graft showed a significantly higher new bone formation (P = .003). Comparing different sizes of $\beta$-TCP/HA, there was no statistical difference in terms of new bone formation. The vertical bone formation (i.e. new bone and graft area) was significantly greater in $\beta$-TCP/HA groups (P = .001). In comparison between different sizes of $\beta$-TCP/HA, medium size group had significantly greater area than large particle size group (P = .039). Conclusion: The use of $\beta$-TCP/HA with titanium mesh showed a higher vertical bone formation, particularly the medium sized $\beta$-TCP/HA particles (0.5 - 1.0 mm) produced better results in vertical bone augmentation.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.308-314
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• 2010

Purpose: The purpose of this study is to analyze the change in re-osseointegration over time and bone reaction at the interface between implant fixture and the surface of the bone, after destroying re-osseointegration by distorting the bone-implant interface artificially. Materials and methods: Experimental implant fixtures (cp titanium, ${\phi}3.75\;mm{\times}4\;mm$) which didn't have surface treatment were produced. Two or three fixtures were implanted on both tibias of twelve female rabbits (New Zealand white, more than 3.5 kg). Then after six weeks, removal torque (RT) was measured and the results were recorded as the first measurement values. The fixtures were submerged again to get reosseointegration between the bone and fixture. To identify the change in re-osseointegration of submerged fixtures over time, six groups had the healing time for four days (group I), one week (group II), two weeks (group III), three weeks (group IV), four weeks (group V) and five weeks (group VI), and then the secondary removal torque was measured for each group. To identify the bone formation under fluorescent light, tetracycline (15 mg/kg, IM) were treated on the rabbits of each group. After the second measurement, the rabbits were sacrificed, and 16 slides were made, two or three for each group. The slides were observed under the fluorescent light with light microscope. To find out the change in the secondary removal torque over the primary removal torque in progress of time, the averages of the increase rate of the primary and secondary torque removal force were calculated. Then, to find out if there were any critical differences between the primary removal torque and the secondary removal torque in each group and among the groups, the results were analyzed statistically by paired t- test, one-way ANOVA, and Duncan's Multiple Range Test. Results: In group I and II, secondary removal torque decreased, especially in group I. In group III, IV, V, and VI, secondary removal torque increased critically. Comparing the differences among the groups, the critical difference was shown between group I, II and group III, IV, V, VI. Mineralization at the interface between the bone and implant fixture was identified from the first week, and bone formation was shown more clearly from the second week. Conclusion: If the implant fixture remains unforced for a certain period of time after the fixture has had iatrogenic mobility, re-osseointegration occurs at the surface of the fixture, and for tibias of rabbits, higher re-osseointegration was obtained within two weeks.

• Journal of Food Hygiene and Safety
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• v.32 no.3
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• pp.179-186
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• 2017

For more efficient and proactive safety control of imported food, new trend in U.S. is emerging, which assesses the food safety control systems of exporting countries using Systems Recognition Assessment Tool and helps ensure safety of imported foods. This study examines trends in development and application of assessmemnt tool and country assessment reports in U.S. where an active discussion on this issue is in progress. The expert interviews were also conducted. U.S. Systems Recognition Assessment Tool was developed by FDA to recognize the potential value in leveraging the expertise of foreign food safety systems and help ensure safety of imported food. The tool is comprised of ten standards and provides an objective framework for determining the robustness of trading partners' overall food safety systems. Using its own tool, the U.S. FDA conducted a preliminary assessment of the food safety control systems of New Zealand and Canada. According to the U.S.-New Zealand and the U.S.-Canada assessment reports, the overall structure of the systems was similar between the countries. In summarizing the opinions of experts, such a trend in National Food Safety Control System Assessment may be utilized in the sanitary assessment and the control of imported food border inspection frequency before importing food. It would contribute to more effective distribution of national budget and increased public trust. Additionally, international collaboration as well as securing of qualified experts and sufficient budget appear to be crucial to further increase the utility of National Food Safety Control Systems Assessment. In conclusion, firstly, it is critically important for the competent authority of South Korea to proactively respond to international trend in National Food Safety Control System Assessment by identifying the details of its background, assessment purpose, core assessment elements, and assessment procedures. Secondly, it is necessary to identify and complement the weaknesses of Korea's food safety control system by reviewing it with U.S. Systems Recognition Assessment Tool. Thirdly, by adapting the assessment results from imported countries' food safety control systems to the imported food inspection intensity, the resources previously used in inspecting the imported food from accredited countries can be redistributed to inspecting the imported food from unaccredited countries, and it would contribute to more efficient imported food safety control. Fourthly, the competent authority of South Korea should also consider developing its own assessment tool designed to reflect the unique characteristics of its food safety control system and international guidelines.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.183-187
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• 2004

Radioactivity in foodstuffs was surveyed for reference in amending regulation on the maximum permitted levels of radioactive contamination of foodstuffs. Most domestic and imported (?) foodstuffs were sampled, some domestic items collected around nuclear power plants to compare site-specific contamination. The collected samples were dried and ashed. Radioactivity in foodstuffs was measured using HPGe gamma spectrometer, Cs-137 activity ranged from 0.025-0.053, 0.045-0.500, 0.062-0.105, 0.025-1.151, 0.021-0.145 and 0.046-0.155 Bq/kg-fresh in cereals, pulses, mot vegetables (potato), ginsengs, meat, and marine products, respectively, with imported dried ginseng showing the highest radioactivity, Results reveal radioactivity in foodstuffs collected in 2002 is far below the maximum permitted levels of 370 Bq/kg. No significant differences were observed in radioactivity among sampling sites and between domestic and imported foodstuffs.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.899-908
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• 2004

The rise of income and introduction of 5 day a week working system give korean people opportunities to enjoy their leisure time. And many korean people have much interest in oceanic sports such as yachting and also oceanic leisure equipments. With the popularization and development of the equipments, the scope of oceanic activities has been expanding in Korea just as in the advanced oceanic countries. However, The current conditions for the sports in Korea are not advanced and even worse than underdeveloped countries. In order to develop the underdeveloped resources of Korean marina, we need to customize the marina models of advanced nations to serve the specific needs and circumstances of Korea As such we have carried out a comparative analysis of how Austrailia, Newzealand, Singapore, japan and Malaysia operate their marina, reaching the following conclusions. Firstly, in marina operations, in order to protect personal property rights and to preserve the environment, we must operate membership and non-membership, profit and non-profit schemes separately, yet without regulating the dress code entering or leaving the club house. Secondly, in order to accumulate greater value added, new sporting events should be hosted each year. There is also the need for an active use of volunteers, the generation of greater interest in yacht tourism, and the simplification of CIQ procedures for foreign yachts as well as the provision of language services. Thirdly, a permanent yacht school should be established, and classes should be taught by qualified instructors. Beginners, intermediary, and advanced learner classes should be managed separately with special emphasis on the dinghy yacht program for children. Fourthly, arrival and departure at the moorings must be regulated autonomically, and there must be systematic measures for the marina to be able, in part, to compensate for loss and damages to equipment, security and surveillance after usage fees have been paid for. Fifthly, marine safety personnel must be formed in accordance with Korea's current circumstances from civilian organizations in order to be used actively in benchmarking, rescue operations, and oceanic searches at times of disaster at sea.

• Journal of Chest Surgery
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• v.43 no.4
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• pp.356-363
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• 2010

Background: Connexin 43-mediated gap junctional communication plays an important role in atherosclerosis. Numerous studies have demonstrated a correlation between mitral valve annular calcification and atherosclerotic disease. However, the relevance of connexin 43 to mitral valve disease remains unclear. We hypothesized that the mechanism contributing to mitral valve disease is associated with alterations in cell-to-cell communication mediated by changes in Connexin 43 expression. Material and Method: Twenty male New Zealand rabbits were divided into two groups: animals in group 1 (n=10) were fed a normal chow diet, whilst those in group 2 (n=10) received a diet containing 1% cholesterol for 12 weeks. After sacrificing the animals, the mitral valves were excised and analyzed with immunohistochemical staining and Real-time Reverse Transcriptase polymerase chain reaction (real time RT-PCR). Result: Myofibroblasts and macrophages were found concentrated within the endothelial layer on the ventricular side of the leaflet in the cholesterol diet group. Immunohistochemial staining showed elevated expression of connexin43 in the cholesterol diet group. Real-time RT-PCR revealed increased connexin43 mRNA levels in mitral valves from hypercholesterolemic animals. Conclusion: Our finding that connexin43 expression is increased in mitral valves of hypercholesterolemic rabbits suggests that alterations in cell-to-cell communication via connexin43 containing gap junctions play a role in the development of mitral valve disease in hypercholesterolemia.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.687-694
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• 2008

Background: Although aortic valve sclerosis causes no significant hemodynamic alterations, it is associated with an increased risk of cardiovascular death and myocardial infarction. However, the role of ${\beta}_3$ integrin in aortic valve sclerosis remains unclear. Material and Method: Twenty male New Zealand rabbits were divided into two groups. Group 1 rabbits (n=10) received a normal chow diet, while group 2 (n=10) rabbits received a diet containing 1% cholesterol for 12 weeks. After the rabbits were euthanized, their aortic valves and ascending aortas were excised for analysis. Result: Total serum cholesterol ($2,148.3{\pm}1,012.5\;mg/dL$ versus $53.7{\pm}31.8\;mg/dL$, p<0.05), triglyceride ($240.4{\pm}218.3\;mg/dL$ versus $31.6{\pm}6.4\;mg/dL$, p<0.05), and low density lipoprotein (LDL)-cholesterol($2,065.3{\pm}960.9\;mg/dL$ versus $29.1{\pm}30.9\;mg/dL$, p<0.05) levels were significantly higher in the cholesterol diet group compared with the normal diet group. Myofibroblasts and macrophages were more highly expressed in the aortic valve leaflets of rabbits in the cholesterol diet group than of those in the normal diet group. A real-time polymerase chain reaction revealed decreased ${\beta}_3$ integrin mRNA levels in the hypercholesterolemic aortic valves and aortas. Conclusion: The present study shows that hypercholesterolemia induces aortic valve sclerosis. These findings suggest that alterations in ${\beta}_3$ integrin may playa role in the development of aortic valve sclerosis.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.3
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• pp.209-214
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• 2010

Purpose: The purpose of this study was to investigate whether the re-osseointegration of the implants that had mechanical unscrewing possibly occurred or not. Furthermore, if it happened, the degree of re-osseointegration was evaluated by comparing with previous osseointegration. Materials and methods: The smooth implant (commercial pure titanium 99%) specimens, whose diameter and length was 3.75 mm, 4 mm, respectively were produced. Two implants were inserted into each tibia of 7 New Zealand female white rabbits weighing at least 3.0 kg. The torque removal force for each implant after 6 weeks of implants placement was measured and included in group I. The torque removal forces were assessed after the fixtures were re-screwed to original position and the subjects were allowed to have 4 more weeks for healing and included in group II. One rabbit was sacrificed after first measurement and produced 4 slide specimens in group I, and two rabbits were sacrificed after 2nd measurement, 7 slide specimens, in group II for histomorphologic investigations. All slide specimens were assessed based on the proportion of BIC (bone-implant contact) as well as CBa (Bone area in the cortical passage) value produced by counting the screw threads embedded in the compact bones under the optical microscopic analysis (${\times}20$). Statistical analysis was conducted to evaluate the torque removal force, BIC and CBa between group I and II. Results: As for the torque removal force, the result was $10.8{\pm}3.6$ Ncm for group I and $20.2{\pm}9.7$ Ncm for group II. Furthermore, the torque removal force of group II increased by 98.1% in average compared to group I (P<.05). On the other hand, histomorphologic analysis displayed that there was no statistical significance in BIC and CBa values between group I and the group II (P>.05), and RT/BIC and RT/CBa between group I and group II were statistically significant (P<.05). Conclusion: It is possible to obtain more substantial re-osseointegration within shorter periods than the period needed for the initial osseointegration in case of iatrogenically unscrewed implants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.129-135
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• 2012

This study was to investigate the heavy metal content of 55 commercial salts in the Seoul area. There were 22 types of solar sea salt, 17 types of processed salt and 16 types of reworked salt. Looked at another way, there were 22 types of domestic salt and 33 types of salt imported from France, the U.S., Japan, Australia, New Zealand, and Argentina. The samples were measured using both a mercury analyzer and an Inductively-Coupled Plasma Optical Emission Spectrometer (ICP-OES). The average heavy metal contents for commercial salts were Pb $0.281{\pm}0.344$, Cd $0.035{\pm}0.221$, Cr $0.364{\pm}0.635$, Cu $0.182{\pm}0.313$, As $0.046{\pm}0.062$, Ni $0.155{\pm}0.247$, Al $5.753{\pm}10.746$, Co $0.028{\pm}0.211$ and Hg $0.001{\pm}0.001$ mg/kg. The leads were detected highly in solar sea salt rather than in processed salt or reworked salt. Also chrome, arsenic and nickel were found more in processed salt. There were large differences in aluminum content between imported solar sea salt and processed salt. Aluminum was highly detected in French products, showing that salt can be affected by regional differences. The weekly average intakes of Pb, Cd, Cr, Cu, and Hg from commercial salt were 1.652% (0.000~6.754), 0.372% (0.000~7.214), 3.177% (0.000~26.279), 0.008% (0.001~0.049), and 0.031% (0.000~0.094) respectively compared with Provisional Tolerable Weekly Intakes established by the Joint FAO/WHO Expert Committee for the evaluation of food safety. The content of heavy metals from commercial salts was determined to be at safe levels.