• Archives of Reconstructive Microsurgery
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• 제5권1호
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• pp.35-45
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• 1996

After transplantation of groin free flap was sucessed by the Daniel and Taylor in 1973, the reconstruction of plastic surgery was extensive and universal due to rapidly developement of anatomic study of the donor site and technique of microvascular surgery. The free tissue transfers is possible to be early activity and rehabilitation by one stage operation. It currently available allow transfer of specific tissue quality as bone, muscle, nerve to achieve a functional and cosmetic result as well as the most favorable secondary defect. But free flaps require critical, skillful technique and lengthy operating time. Also it has disadvantage of donor site morbity at the large tissue transfer. Authors were transferred with 107 cases in 103 patients from May 1987 to June 1996, and then we analysed free tissue transfer to acquire more increased sucess rate, satisfactory functional and cosmetic results. The sexual distribution was male prominent in 79 cases(76.7%), female in 24(23.3%) and age was variable distribution from 3 to 76 years old. The cause of defects was most prevalent in trauma of traffic and industrial accident in 51 cases(49%). The common recipient site were lower extremities in 47 cases(43.9%), upper extremities in 28 cases(26.5%), head and neck in 25 cases(23.4%), and trunk in 7 cases(6.5%). The type of transfer were free skin flaps in 46 cases(43%), free muscle or musculocutaneous flaps in 31 cases(29%), free vasculized or osteocutaneous flaps in 10 cases(9.3%), and specilized free flaps in 20 cases(18.7%). The anastomosis of artery was end to end anastomosis in 94 cases(87.9%), end to side anastomosis in 13 cases(12.1%) and all vein was end to end anastomosis. The number of anastomosed vessels were one artery one vein in 62 cases(57.9%), one artery two vein in 45 cases(42.1%) and vein graft was performed only one case. The postoperative mornitoring were used with temperature, color of flap, capillary refilling time, ultrasonogram, bone scan, doppler, and endoscopy. The reexploration was performed in 9 cases(8.4%), and then flap was loss in 3 cases(2.8%). Accordingly overall success rate was 97.2%. The postoperative complication was early vascular occlusion, hematoma, partial necrosis and late bulkiness, scarring, color dismatch etc. Therefore, free tissue transfer is the preferred method of treatment, even through conventional local and distant flaps are available.

• Archives of Plastic Surgery
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• 제33권3호
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• pp.289-293
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• 2006

By means of microsurgical free-tissue transfer providing a large amount of required tissue, the surgeon can resect tumoral tissue more safely, which allows tumor-free margins and enhances the reliability of the ablative surgery that otherwise could not be performed radically. The morbidity of elective free-tissue transfer seems to be quite low, carrying acceptable risks for most patients. But the elderly patients are at risk for cardiac and respiratory problems, deep vein thrombosis, pulmonary emboli and infection merely as a function of age. This study was undertaken to define further risks of the elderly population with regards to free-tissue transfer. We retrospectively reviewed our experience with 110 microsurgical free-tissue transfers for head and neck reconstruction in patients greater than 60 years of age. Microsurgical procedures in all cases were preformed by the plastic and reconstructive department at Yonsei medical center. The investigated parameters were patient demographics, past medical history, American Society of Anesthesiologists(ASA) status, site and cause of defect, the free tissue transferred and postoperative complication including free-flap success or failure. There were 46 patients in the age group from 60 to 64 years, 34 patients from 65 to 70 years, and 30 patients 70 years or older. There happened 3 flap losses, resulting in a flap viability rate of 97%. Patients with a higher ASA designation experienced more medical complication(p=0.05, 0.01, 0.03 in each age group I, II, III) but not surgical complication p=0.17, 0.11, 0.54 in each age group I, II, III). And the relationship between postoperative complication and age groups was not significant. These observations suggest that major determinant for postoperative medical complication be the patient's American Society of Anesthesiologists score, and chronologic age alone should not be an exclusion criterion when selecting patients for free-tissue transfer

• Journal of Chest Surgery
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• 제22권2호
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• pp.220-224
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• 1989

In candidates for aortic valve replacement [AVR]it is our primary intention to implant the largest possible vale prosthesis of at least 23 mm in diameter in patients with severe valvular aortic stenosis. However, in many patients there is an additional subvalvular asymmetric septal hypertrophy which in some cases may cause an postextrasystolic increase of the LV-aortic gradient. Another component of the aortic stenosis syndrome is a narrow valvular ring, or a combination of both. After complete removal of the diseased valve and decalcification the narrow aortic ring [< 23 mm] can be widened firstly by transaortic subvalvular septal myectomy- [TSM] thus unfolding the left ventricular outflow tract[LVOT]and secondly by extending the oblique aortic incision into the aortic valve ring or further down into the anterior leaflet of the mitral valve. The sub-and supra-valvular defect will be closed by patch enlargement of the aortic root [PEAR] using autologous pericardium. These techniques allow a considerable enlargement of the valvular ring of about 4 to 10 mm in circumference. In a retrospective study using a computerized program, 847 patients with AVR [1980-1984]were reviewed to evaluate the intraoperative hemodynamic results mainly concerning relief of the transvalvular gradient. In 626 patients AVR was performed, 151 patients had double valve replacement [AVR+MVR], and 70 patients had AVR plus additional surgical procedures. Concentrating on the AVR-group [n=626] there were 103 patients with TSM, 24 patients with PEAR and 20 patients with TSM+PEAR which demonstrated that in a total, of 147 patients of this groups [23.5%] an additional procedure was necessary. The Statistical evaluation of the intraoperative pressure measurements before and after AVR in relation to the size of the implanted prostheses indicated the lowest preoperative mean gradient in patients with AVR alone, the highest in patients who afforded TSM plus PEAR. However, after AVR the mean gradients in all three groups were very low [mean 5 to 10 mmHg]. These data indicate that in patients with a narrow aortic ring and additional considerable ASH, TSM and PEAR are suitable techniques to enlarge the aortic root to enable the implantation of an adequate aortic valve prosthesis. Long-term controls have shown that autologous pericardium is a qualified graft material for the ascending aorta.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권2호
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• pp.103-111
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• 2011

Purpose: Choukroun's platelet-rich-fibrin (PRF) is composed of platelets, white blood cells and fibrin matrix. It does not induce enough bone formation by itself but it can improve bone formation with calcium. Silk fibroin does not cause inflammatory reactions because it is bio-compatible and degradable. The purpose of this study was to exam the bone formation when a combination of Choukroun's PRF and silk fibroin was used. Methods: In this study, cell reactions to silk powder with differing molecular weights was first tested to select the appropriate silk powder. Then we applied these bone graft materials on defects of skull and in a peri-implant bony defect model in New Zealand rabbits. The results between the experimental and control s (non-grafted) group were analyzed. Results: The small sized silk fibroin powder showed increased cellular proliferation for bone-regeneration. There was no statistically significant difference between the experimental group and the control group at 6 weeks, but more new bone formation was observed in the combination graft group at 12 weeks (P<0.05). And in the dental implant model, the combination bone graft group showed much improved torque test results, which was statistically significant. Histomorphometric analysis showed more regenerated cortical bone and a higher mean bone to implant in the experimental group. Both were statistically significant. Conclusion: The combination graft of Choukroun's platelet-rich-fibrin (PRF) and silk fibroin powder can successfully restore the bony defects in a skull defected model and a peri-implant bony defects model.

• Journal of the Korean Institute of Gas
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• 제5권3호
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• pp.45-50
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• 2001

Open rack vaporizer (ORV) has been used in liquefied natural gas (LNG) receiving terminal in order to vaporize LNG into natural gas (NG) by heat exchange with seawater The U-type ORV which had been operated with seawater for 14 years is one of the important utilities of the gas production and the weld part of tube connected with header_ pipe had experienced many corrosion problems. To elucidate the cause of corrosion at weld part of vaporizer tube, corrosion potentials were compared by parts. This study concerns on the measurement of corrosion pit depth using non-destructive method and the evaluation of stress distribution in an aspect of safety with finite element analysis. In order to confirm the reliability of galvanic corrosion between weld parts and base metal, the measurement of corrosion potential by parts was conducted for 20 minutes in 3.5$\%$(wt.) NaCl solution. Many non-destructive methods were tried to measure the remaining thickness of vaporizer tube at fields. For general corrosion, tangential radiography test was confirmed as an effective method. In case of a fine corrosion pit, the shape of corrosion pit was reproduced using surface replication method. From collected data, stress distributions were quantitatively evaluated with 2-dimensional finite element method and the diagnostic evaluation on internal pressure of the U-type vaporizer could be made.

• Journal of Korean Neurosurgical Society
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• 제46권3호
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• pp.232-238
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• 2009

Objective : Intracranial aneurysms are sometimes presented with visual symptoms by their rupture or direct compression of the optic nerve. It is because their prevalent sites are anatomically located close to the optic pathway. Anterior communicating artery is especially located in close proximity to optic nerve. Aneurysm arising in this area can produce visual symptoms according to their direction while the size is small. Clinical importance of visual symptoms presented by aneurysmal optic nerve compression is stressed in this study. Methods : Retrospective analysis of ruptured anterior communicating artery aneurysms compressing optic apparatus were carried out. Total 33 cases were enrolled in this study. Optic nerve compression of the aneurysms was confirmed by the surgical fields. Results : In 33 cases among 351 cases of ruptured anterior communicating artery aneurysms treated surgically, from 1991 to 2000, the dome of aneurysm was compressed in optic pathway. In some cases, aneurysm impacted into the optic nerve that deep hollowness was found when the aneurysm sac was removed during operation. Among 33 cases, 10 cases presented with preoperative visual symptoms, such as visual dimness (5), unilateral visual field defect (2) or unilateral visual loss (3), 20 cases had no visual symptoms. Visual symptoms could not be checked in 3 cases due to the poor mental state. In 6 cases among 20 cases having no visual symptoms, optic nerve was deeply compressed by the dome of aneurysm which was seen in the surgical field. Of 10 patients who had visual symptoms, 8 showed improvement in visual symptoms within 6 months after clipping of aneurysms. In 2 cases, the visual symptoms did not recover. Conclusion : Anterior communicating artery aneurysm can cause visual symptoms by compressing the optic nerve or direct rupture to the optic nerve with focal hematoma formation. We emphasize that cerebral vascular study is highly recommended to detect intracranial aneurysm before its rupture in the case of normal CT findings with visual symptoms and frequent headache.

• Childhood Kidney Diseases
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• 제12권2호
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• pp.186-193
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• 2008

Purpose : Intrarenal reflux(IRR) is backflow of urine from the renal pelvis into the collecting ducts. IRR is the main cause of renal injury in children with vesicoureteral reflux (VUR) which leads to renal scars, hypertension, proteinuria, and chronic renal failure. The purpose of our study was to investigate the characteristics of intrarenal reflux. Method : We retrospectively reviewed the medical records of 80 patients who were diagnosed as having grades of III-V VUR from Jan. 2004 to Dec. 2006 in the department of pediatrics in Ajou University Hospital. The patients were divided into two groups according to the presence of IRR on voiding cystoureterogram and compared to each other for the possible factors associated with intrarenal reflux. Results : Among 80 VUR patients, IRR(＋) group comprised 17(21.3%) patients and 27 renal units(23.2%) and revealed younger age, higher grade of VUR, and more proteinuria compared to IRR(-) group. There were no significant difference in gender, laboratory findings and the rate of resolution in VUR or defects on renal scan between two groups. Also, intrarenal reflux mostly corresponded to the same site of photon defects on DMSA scan. Conclusion : We suggest that intrarenal reflux tends to be associated with younger age, higher grade of reflux, more proteinuria with no difference in resolution rate of VUR when compared to the VUR patients without IRR. From this study, we were able to understand the characteristics of intrarenal reflux in children with urinary tract infection.

• Advances in pediatric surgery
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• 제1권2호
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• pp.140-148
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• 1995

To study the clinical profiles and outcome of surgery in infants with esophageal atresia, we reviewed 96 esophageal atresia cases who were treated from April, 1978 to June, 1995. There were 51 male and 45 female infants, a ratio of 1.1:1. The low birth weight(<2500g) patients were 32%. Clinical findings at the time of diagnosis included drooling in 57%, choking in 50%, cyanosis in 38%, respiratory distress in 27% and swallowing difficulty in 20%. Gross classification included 6 cases of type A esophageal atresia(6%), 79 cases of type C(82%), 3 cases of type E (3%) and 8 cases of type F(8%). Associated anomalies occurred in 34 infants(35%). Among them, cardiac anomalies were most common(60%). A primary repair of the defect was carried out in 76 patients with type A or C. A staged operation comprising a repair or gastric tube interposition after gastrostomy was performed in 8 patients. In all 3 infants with H-type, a division of fistula was performed. Esophageal resection and anastomosis was done in 8 infants with esophageal stenosis. In one infant, a gastrostomy was performed and he expired before staged operation. Anastomotic complications included leakage in 16 cases(17%), stricture in 37 cases(39%) and recurrent tracheoesopohageal fistula in 3 cases(3%). The mortality rate was 14% and the leading cause of death was pneumonia. The overall survival rate was 86%, and according to Waterston criteria, the survival rates were 93%, 85% and 58% in class A, Band C, respectively. 75 patients were followed up with median follow up 6.4 years. Among them, 93% were uneventful and 7% had frequent pneumonia.

• Journal of Korean Neurosurgical Society
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• 제29권11호
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• pp.1415-1420
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• 2000

Essential tremor(ET) is the most common movement disorder however there has been little agreement in the neurologic literature regarding diagnostic criteria for ET. Familial ET is an autosomal dominant disorder presenting as an isolated postural tremor. The main feature of ET is postural tremor of the arms with later involvement of the head, voice, or legs. In previous studies, it was reported that ET susceptibility was inherited in an autosomal dominant inheritance. As with previous results, it would suggest that ET might be associated with defect of mitochondrial or nuclear DNA. Recent studies are focusing molecular genetic detection of movement disorders, such as essential tremor and restless legs syndrome. Parkinson's disease(PD) is a neurodegenerative disease involving mainly the loss of dopaminergic neurons in substantia nigra by several factors. The cause of dopaminergic cell death is unknown. Recently, it has been suggested that Parkinson's disease many result from mitochondrial dysfunction. The authors have analysed mitochondrial DNA(mtDNA) from the blood cell of PD and ET patients via long and accurate polymerase chain reaction(LA PCR). Blood samples were collected from 9 PD and 9 ET patients. Total DNA was extracted twice with phenol followed by chloroform : isoamylalcohol. For the analysis of mtDNA, LA PCR was performed by mitochondrial specific primers. With LA PCR, 1/3 16s rRNA~1/3 ATPase 6/8 and COI~3/4 ND5 regions were observed in different patterns. But, in the COI~1/3 ATPase 6/8 region, the data of PCR were observed in same pattern. This study supports the data that ET and PD are genentic disorders with deficiency of mitochondrial DNA multicomplexes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제31권5호
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• pp.307-312
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• 2018

Liquid phases in ZnO varistors cause more complex phase development and microstructure, which makes the control of electrical properties and reliability more difficult. Therefore, we have investigated 2 mol% $CaCO_3$ doped $ZnO-Co_3O_4-Cr_2O_3-La_2O_3$ (ZCCLCa) bulk ceramics as one of the compositions without liquid phase sintering additive. The results were as follows: when $CaCO_3$ is added to ZCCLCa ($644{\Omega}cm$) acting as a simple ohmic resistor, CaO does not form a secondary phase with ZnO but is mostly distributed in the grain boundary and has excellent varistor characteristics (high nonlinear coefficient ${\alpha}=78$, low leakage current of $0.06{\mu}A/cm^2$, and high insulation resistance of $1{\times}10^{11}{\Omega}cm$). The main defects $Zn_i^{{\cdot}{\cdot}}$ (AS: 0.16 eV, IS & MS: 0.20 eV) and $V_o^{\bullet}$ (AS: 0.29 eV, IS & MS: 0.37 eV) were found, and the grain boundaries had 1.1 eV with electrically single grain boundary. The resistance of each defect and grain boundary decreases exponentially with increasing the measurement temperature. However, the capacitance (0.2 nF) of the grain boundary was ~1/10 lower than that of the two defects (~3.8 nF, ~2.2 nF) and showed a tendency to decrease as the measurement temperature increased. Therefore, ZCCLCa varistors have high sintering temperature of $1,200^{\circ}C$ due to lack of liquid phase additives, but excellent varistor characteristics are exhibited, which means ZCCLCa is a good candidate for realizing chip type or disc type commercial varistor products with excellent performance.