• The korean journal of orthodontics
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• v.33 no.4 s.99
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• pp.279-291
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• 2003

Electric current is a highly probable way as a clinical tool for tooth movement. The purposes of this study were to determine the usefulness of exogenous electric currents in accelerating orthodontic tooth movement and to investigate the effects of electric-orthodontic treatment on the remodeling of the periodontal tissue histologically The study was performed with six male cats weighing around 3kg. The electric device wich is providing the direct electric current of $20{\mu}A$ was inserted to the removable appliance. The right and left maxillary canines were assigned as control and experimental sides respectively. The control canine was Provided with orthodontic force (75gm) oかy and the experimental side was given the same amount of force and electricity. The lingual buttons were bonded to the maxillary canines and both sides of canines were retracted with NiTi coil spring. The electric device was adjusted to provide 20uh direct current to the experimental canines S hours a day The amount of the canine movement was measured with electronic caliper every week. After 4 weeks of tooth movement, the animals were sacrificed and the histologic study was performed. The results of this study were as follows. 1. The application of a direct current to the experimental tooth significantly increased the final amount of orthodontic tooth movement. The amount of tooth movement after 28-day was 37% more in the experimental side. 2. The electrically stimulated tooth showed histologic evidence of significant increases in the amount of bones and matrix deposition in the area of tension. 3. In the compression side, the electric-orthodontic treatment stimulated bone resorption more extensively in the experimental canines. 4. After 28 days of electricity exposure and orthodontic force, the experimental side demonstrated significantly more osteoblasts, osteoclasts, capillaries and osteoid tissues, reflectinr an increase in the local tissue's cellular activity. 5. Intermittent electrical stimulation (five hours a day) had effects to enhance orthodontic tooth movement and tissue remodeling. These results suggested that the low-intensity exogenous electric current by the miniature electric device might accelerate orthodontic tooth movement and bone remodeling in vivo and have the possibility to reduce the orthodontic treatment duration.

• The korean journal of orthodontics
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• v.41 no.6
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• pp.399-410
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• 2011

Objective: The purpose of this study was to evaluate the difference in frictional resistance among metal, ceramic, self-ligation brackets and coated or non-coated Ni-Ti archwires at various bracket-archwire angulations during the sliding movement of an orthodontic archwire, using an orthodontic sliding simulation device. Methods: Four types of bracket (Micro-arch Perpect Clear2 Clippy-C and Damon3 and 5 types of orthodontic archwire (0.014", 0.016", and 0.016" ${\times}$ 0.022" inch coated Ni-Ti, and 0.016" and 0.016" ${\times}$ 0.022" inch Ni-Ti) were used. Further, the bracket- archwire angles were set at 4 different angulations: $0^{\circ}$, $3^{\circ}$, $6^{\circ}$, and $9^{\circ}$. Results: The frictions from all the experimental groups were found to be significantly increased in order of self-ligation brackets, Micro-arch and Perpect Clear2 ($p$ < 0.001). The presence of a coat had no effect on the friction of the same sized archwires at $0^{\circ}$ and $3^{\circ}$ bracket-archwire angles ($p$ < 0.001). Coated archwires had significantly higher frictions than the same sized non-coated archwires at $6^{\circ}$ and $9^{\circ}$ bracket-archwire angles ($p$ < 0.001). The frictions increased significantly as the bracket-archwire angles were increased ($p$ < 0.001). Conclusions: The use of self-ligation brackets will be beneficial in clinical situations where a low frictional force is required. Further, in cases where crowding is not severe, the use of coated archwires should not cause problems. However, more additional explanation is required considering the fact that the damage of coated archwire and exposure of the metal portion in case of binding and notching and the effects of saliva were not taken into account.

• Journal of Korean Neurosurgical Society
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• v.30 no.9
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• pp.1065-1071
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• 2001

Object : This study was conducted to evaluate whether short-term intravenous infusion of tranexamic acid (AMCA) was able to improve the management outcome by preventing rebleeding without increasing vasospasm and hydrocephalus associated with the long-term administration of this agent in the patients with aneurysmal subarachnoid hemorrhage(SAH) who were planned for the early surgery. Methods : During the period from June, 1996 to May, 1998, 137 patients admitted within 3 days of their SAH and planned for early surgical intervention were subject to study population. Of these, 60 patients who had been treated with AMCA were classified as AMCA treated group and 77 patients without AMCA treatment as AMCA untreated group. Initially, prognostic factors for rebleeding, vasospasm, hydrocephalus and outcome following SAH including age, sex, clinical grade, CT grade, site of ruptured aneurysms, admission day after SAH, surgery day after SAH, number of aneurysms and hypertension history, were analyzed and compared between AMCA treated group and untreated group. Secondly, the incidence of rebleeding, symptomatic vasospasm and hydrocephalus were compared between the two groups. Also, the management outcome of the patients was compared between the two groups. Results : There were no significant differences in prognostic factors between the two groups. The rebleeding rate was 0% in the AMCA treated group whereas the rate was 7.8% in the untreated group. This difference was statistically significant. The incidences of symptomatic vasospasm and hydrocephalus were found not to be significantly different between the two groups. Of the treated group, 31.7% of patients developed hydrocephalus compared to 32.5% of those at the untreated group. Fourteen(23.3%) patients in treated group developed symptomatic vasospasm and 6 of them(10%) suffered stroke whereas incidences of these in untreated group were 25.9% and 11.7%, respectively. The AMCA treated group showed more favorable outcome than that of untreated group. There was no case of death by rebleeding in the AMCA treated group while one of the main causes of death in the untreated group was rebleeding. Conclusion : Short-term high-dose AMCA administration is considered beneficial in improving outcome and diminishing the risk of rebleeding in the patients who suffer from an aneurysmal SAH prior to early surgical intervention.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.334-340
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• 2010

It is well known that smoking as well as drinking is a factor of stomatopathy, however there are few investigations about comparison of oral flora between smokers and non-smokers. In this study, we isolated the oral flora of 30 smokers and 30 non-smokers and cultured them on blood agar plates. The isolated pathogenic microorganisms were tested for antibiotic susceptibility and resistance using the Kirby-Bauer antibiotic testing method. Each colony was stained using the Gram staining method and was identified by an automatic identifier, known as the VITEK system. We isolated 41 colonies from smokers' oral cavity, and they were sorted as 63% of Gram-positive cocci, 29% of Gram-negative cocci, 3% of Gram-positive bacilli, and 5% of Gram-negative bacilli by gram staining, whereas 38 colonies were isolated from non-smoters' oral cavity, and their proportions were 55% of Gram-positive cocci, 26% of Gram-negative cocci, 3% of Gram-positive bacilli, and 16% of Gram-negative bacilli. The VITEK system revealed specific distribution of bacteria species that Streptococcus mutans (6/41), Gemella morillorum (6/41), Streptococcus oralis (2/41), Streptococcus pneumoniae (1/41), Staphylococcus aureus (3/41), Streptococcus anginosus (1/41), Streptococcus intermedius (1/41), Streptococcus uberis (1/41), and Streptococcus sanguinis (1/41) in smokers oral cavity whereas Streptococcus sanguinis (8/38), Staphylococcus aureus (1/38), Staphylococcus auricularis (1/38), Streptococcus uberis (1/38), Streptococcus intermedius (1/38), Streptococcus mutans (1/38), and Streptococcus oralis (1/38) in those of non-smokers'. Three cases of Staphylococcus aureus from smokers produced Beta-lactamase and were identified methicillin-resistance Staphylococcus aureus (MRSA). However one case of Staphylococcus aureus from non-smoker did not produce Beta-lactamase and was sensitive to methicillin. In conclusion, the distribution of oral flora was different between smokers' and non-smokers' oral cavity, especially Gemella morillorum and MRSA were predominantly found in smoker's oral cavity. These results are useful in the treatment and prevention of patients with stomatopathy caused by smoking.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.178-185
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• 2005

Purpose : The purpose of this study was to evaluate the outcome of children with juvenile myelomonocytic leukemia(JMML) treated with allogeneic hematopoietic stem cell transplantation(allo-HSCT). Methods : Eleven JMML patients aged 8-39 months underwent allo-HSCT. The sources of grafts were unrelated donors(n=7), HLA-matched siblings(n=3) and an HLA 1-antigen mismatched familial donor. All patients had received chemotherapy ${\pm}13$-cis-retinoic acid(CRA) before transplant, and CRA was used, posttransplant, in six patients. Results : Only three patients were in complete remission(CR) at the time of transplantation. Initial chimeric status revealed complete donor chimerism(CC) in five patients, mixed chimerism(MC) in five and autologous recovery(AR) in one. One patient with MC having persistent splenomegaly eventually turned to CC and CR after rapid tapering of cyclosporine, combined with daily use of CRA. An AR case relapsed shortly after transplant but was rescued with second, unrelated cord blood transplantation. Ultimately, six patients are alive, event-free, with a median follow-up of 15.5 months posttransplant. All three deaths occurred in patients who failed to achieve CC, leading to disease progression. Conclusion : We suggest that graft-versus-leukemia effect play an important role and CRA a possible role in posttransplant leukemic involution in JMML. In patients whose leukemic burden is still high with MC after transplant, early tapering of immunosuppressants and introduction of CRA might provide a chance of a cure for some patients.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1512-1518
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• 2002

Purpose : Twins have a higher mortality and morbidity than singletons. Co-twin with one fetal death is particularly at risk. We investigated the neonatal outcome of live co-twins when one fetus had died after the 20th gestational week, and associated risk factors. Methods : A retrospective study was performed in fifteen cases of twin pregnancy with single intrauterine fetal deaths after the 20th gestational week during the period from January 1996 to December 2000 at Chonnam University Hospital. Results : Gestational age was $33.7{\pm}3.2weeks$, birth weight was $1,992{\pm}592g$. Interval between one fetal death being detected and the delivery of a live co-twin was $32.4{\pm}29.5days$. There were 11 cases(73.3%) of premature babies less than 37 gestational weeks. Main causes of preterm delivery were preterm labor and premature rupture of membranes. Hematologic findings suggesting disseminated intravascular coagulopathy(DIC) were not found in all mothers before delivery, and was not associated with DIC and encephalomalacia of the live co-twin. Perinatal outcome of fifteen live co-twins was as follows : six were normal(40%), three were DIC(20.0%), three were encephalomalacia(20.0%), one suffered intrauterine growth retardation, there was one case of twin to twin transfusion syndrome, and one of congenital heart disease(atrial septal defect with pulmonary stenosis). The occurrence of DIC and encephalomalacia in live co-twins was not related to placental chorionicity, birth weight, gestational week, and the interval between the detection one fetal death and the delivery of a live co-twin. Conclusion : We could not find any maternal hematologic problems in twin pregnancies complicated by one fetal death. Twenty percent of live co-twins showed DIC and encephalomalacia. However, its associated risk factors were not found. We need to investigate more closely the cases of live co-twins with one intrauterine fetal death.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.309-315
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• 1985

This study was designed to compare the lipid components between wild and cultured snakehead, Channa argus. The lipid components of cultured snakehead were analyzed and compared with that of wild snakehead. In both edible portion and viscera, the lipid content in cultured, snakehead was higher than that in wild one. In the fatty acid composition of neutral lipid in edible portion, percentages of $C_{14:0},\;C_{16:0},\;C_{18:1},\;C_{20:5},\;C_{22:5}\;and\;C_{22:6}$ in cultured snakehead were higher than those in wild one, while percentages of $C_{18:0},\;C_{16:1},\;C_{18:2},\;C_{18:3},\;C_{20:4}\;and\;C_{22:4}$ lower. In the case of phospholipid in edible portion, percentages of $C_{16:0},\;C_{18:1}\;and\;C_{22:6}$ in cultured snakehead were higher than those in wild one, while percentages of $C_{16:1},\;C_{18:2},\;C_{18:3},\;C_{20:4},\;C_{22:4}\;and\;C_{22:5}$ lower. The unsaturation (TUFA/TSFA) and w3 highly unsaturated fatty acid content (w3 HUFA) of neutral lipid in cultured snakehead were higher than those in wild one, while those of phospholipid lower. The essential fatty acid contents (TEFA) of both neutral and phospholipids in wild snakehead were higher than those in cultured one. In the ratio (A/B) of fatty- acid content (A) in cultured snakehead to that (B) in diet, the A/B ratios of $C_{18:2\;w6},\;C_{18:3\;w3},\;C_{20:5\;w3}\;and\;C_{22:6\;w3}$ were 0.3 to 2.5 times, and it is considered to be related to the biosynthesis of polyenoic acids and growth rate of cultured snakehead.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.1-9
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• 2001

Purpose : To establish the role of stereotactic radiosurgery (SRS) for the treatment of patients with angiographically occult vascular malformation (AOVM). Materials and Methods : Eleven patients (12 lesions) with AOVM were treated with linear accelerator-based SRS between February 1995 and December 1999. A magnetic resonance imaging of each patients showed well-circumscribed vascular lesion with reticulated core of heterogeneous signal intensity and peripheral rim of low signal intensity. SRS were peformed with the median peripheral dose of 16 Gy (range 13~25). A single isocenter was used with median collimator size of 14 mm (range 8~20) diameter. Results : With a median follow-up period of 42 months (range 12~56), rebleeding occurred in 3 AOVMS at 5, 6 and 12 months after SRS but no further bleeding did. Two patients experienced radiation-induced necrosis associated with permanent neurologic deficit and one patient showed transient edema of increased 72 signal intensity. Conclusion : SRS may be effective for the prevention of rebleeding in AOVM located in surgically inaccessible region of the brain. Careful consideration should be needed in the decision of case selection and dose prescription because the incidence of radiation-induced complications is too high to be accepted.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.150-156
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• 2000

Purpose : Stereotactic radiation therapy (SRT) can deliver highly focused radiation to a small and spherical target lesion with very high degree of mechanical accuracy. For non-spherical and large lesions, however, inclusion of the neighboring normal structures within the high dose radiation volume is inevitable in SRT This is to report the beam shaping using the partial closure of the independent jaw in SRT and the verification of dose calculation and the dose display using a home-made soft ware. Materials and Methods : Authors adopted the idea to partially close one or more independent collimator jaw(5) in addition to the circular collimator cones to shield the neighboring normal structures while keeping the target lesion within the radiation beam field at all angles along the arc trajectory. The output factors (OF's) and the tissue-maximum ratios (TMR's) were measured using the micro ion chamber in the water phantom dosimetry system, and were compared with the theoretical calculations. A film dosimetry procedure was peformed to obtain the depth dose profiles at 5 cm, and they were also compared with the theoretical calculations, where the radiation dose would depend on the actual area of irradiation. Authors incorporated this algorithm into the home-made SRT software for the isodose calculation and display, and was tried on an example case with single brain metastasis. The dose-volume histograms (DVH's) of the planning target volume (PTV) and the normal brain derived by the control plan were reciprocally compared with those derived by the plan using the same arc arrangement plus the independent collimator jaw closure. Results : When using 5.0 cm diameter collimator, the measurements of the OF's and the TMR's with one independent jaw set at 30 mm (unblocked), 15.5 mm, 8.6 mm, and 0 mm from th central beam axis showed good correlation to the theoretical calculation within 0.5% and 0.3% error range. The dose profiles at 5 cm depth obtained by the film dosimetry also showed very good correlation to the theoretical calculations. The isodose profiles obtained on the home-made software demonstrated a slightly more conformal dose distribution around the target lesion by using the independent jaw closure, where the DVH's of the PTV were almost equivalent on the two plans, while the DVH's for the normal brain showed that less volume of the normal brain receiving high radiation dose by using this modification than the control plan employing the circular collimator cone only. Conclusions : With the beam shaping modification using the independent jaw closure, authors have realized wider clinical application of SRT with more conformal dose planning. Authors believe that SRT, with beam shaping ideas and efforts, should no longer be limited to the small spherical lesions, but be more widely applied to rather irregularly shaped tumors in the intracranial and the head and neck regions.

• The Korean Society of Law and Medicine
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• v.21 no.1
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• pp.223-259
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• 2020

With COVID-19 spreading rapidly around the world, research and development issues on treatments and vaccines for the virus are of high interest. Among them, Remdesivir was the first to show noticeable therapeutic effects and began clinical trials, with each country authorizing the use of the drug through emergency approval. However, Gilead Co., Ltd., the developer of Remdesivir, received a lot of criticism from civic groups for submitting the application for the marketing authorization as an orphan drug. This is because when a new drug got a marketing authorization as an orphan drug could be granted an exclusive status for seven year. The long-term exclusive status of an orphan drug comes from the policy purpose of motivating pharmaceutical companies to develop treatment opportunities for patients suffering from rare diseases, which was not appropriate to apply to infectious disease treatments. This paper provides a review of the problems and improvement directions of the domestic system through comparative legal consideration against the United States, Europe and Japan for the statutes which give exclusive status to medicines. The domestic system has a fundamental problem that it does not have explicit provisions in the statute in the manner of granting exclusive status, and that it uses the review system to give it exclusive status indirectly. In addition, in the case of orphan drugs, the "Rare Diseases Management Act" and the "Regulations on Examination of Items Permission and Reporting of Drugs" provide overlapping review periods, and despite the relatively long monopoly period, there seems to be no check clause to recover exclusive status in the event of a change in circumstances. Given that biopharmaceuticals are difficult to obtain patents, the lack of such provisions is a pity of domestic legislation, although granting exclusive rights may be a great motivation to induce drug development. In the United States, given that the first biosimilar also has a one-year monopoly period, it can be interpreted that domestic legislation is quite strictly limited to granting exclusive status to biopharmaceuticals. The need for improvement of the domestic system will be recognized in that it could undermine local pharmaceutical companies' willingness to develop biopharmaceuticals in the future, and in that it is also necessary to harmonize international regulations. Taking advantage of the emergence of COVID-19 as an opportunity, we look again at the problems of the domestic system that grants exclusive rights to medicines and hope that an overall revision of the relevant legislation will be made to establish a unified legal basis.