• Journal of Korean Neurosurgical Society
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• v.30 no.11
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• pp.1291-1299
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• 2001

Objectives : The authors present a retrospective analysis of 14 patients treated for spinal cord hemangioblastoma (SCH) between Dec. 1986 and Mar. 2000. This study was conducted to evaluate and compare the difference of the functional outcomes associated with the extent of surgical removal of SCH. Methods : Eleven patients were male and three patients were female. Their mean age was 37.2 years that ranged from 19 to 62 years. Preoperative magnetic resonance(MR) imaging of the spine was performed in all cases, and preoperative angiography in eleven cases. They were followed from 15 months to 161 months(median follow-up period, 47 months), and we investigated the change of neurological symptoms and functional outcomes with radiological features, especially on MR imaging. Results : Six patients were accompanied by von Hippel-Lindau disease, and three of them had multiple CNS tumors. Thirteen patients had intramedullary tumor, and the remaining one had extradural. Syringomyelia around the tumor was observed in ten cases. All patients underwent surgical removal, and gross total removal(GTR) was achieved in ten cases. Preoperative embolization was performed in four cases. In four patients who were treated with preoperative embolization, intraoperative loss of blood was minimal and GTR was possible. One patient developed a transient swallowing difficulty postoperatively without permanent postoperative neurological deficits. In three of four patients in whom GTR was not possible, their functional outcomes were worsened postoperatively. The functional status at discharge was improved in seven patients, stationary in four patients, and worse in three. At the last follow-up(15-161 months), one of four patients who had been stationary at discharge showed improvement but, the rest did not show any change. All patients who showed neurological improvement were patients with GTR, and the patients with GTR had significant better outcome than those without GTR(p=0.015). Conclusion : Surgical treatment, and especially, GTR is considered as treatment of choice for spinal cord hemangioblastoma. Preoperative embolization may prevent intraoperative bleeding and improve surgical outcome.

• Advances in pediatric surgery
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• v.15 no.1
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• pp.27-37
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• 2009

Neuroblastoma is the most common extracranial solid tumor in children. We retrospectively analyzed the results of neuroblastoma treatment of 191 patients (116 males and 75 females) treated between January 1986 and December 2005 at the Department of Pediatric Surgery and the Department of Pediatrics, Seoul National University Children's Hospital. The mean age at diagnosis was 3.1 years (0.1 yrs - 13.5 yrs). Forty-seven patients were under 1 year of age. The mean follow-up period was 57.3 months (24 days - 19.1 yrs). Patients were classified into two groups according to the completeness of resection of the primary tumor; (1) gross total resection (GTR) and (2) incomplete resection (IR). The number of patients in stages I, II, III, IV, IV-S were 17 (8.9 %), 12 (6.3 %), 43 (22.5 %), 114 (59.7 %), 4 (2.1 %), respectively. GTR was achieved in 120 patients and IR in 71 (22 stage III, 47 stage IV, 1 stage IV-S, 1 brain). Overall survival (OS) was 65.2 % and event-free survival (EFS) was 48.6 %. EFS were 100 %, 75 %, 66.8 %, 31.3 %, 75 % at stage I, II, III, IV, IV-S, respectively. There was no significant difference in EFS according to the completeness of resection. EFS was improved in GTR group (p=ns) of stage III, but by contrast, stage IV patients showed worse EFS in GTR group. EFS was improved significantly after the introduction of autologous stem cell transplantation (ASCT) (58.1% vs. 40.6%, p=.029). The EFS improved significantly after the introduction of ASCT in IR group (p=.009) rather than GTR group (p=ns). The EFS of the patients under 1 year of age (N=47) was better than the patients over 1 year of age (N=144) significantly (75.5 % vs. 39.4 %, p=.0034). The prognosis of neuroblastoma was related to the INSS stage and age at diagnosis. The survival of IR group significantly improved after ASCT.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.993-999
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• 2011

The photoreactive prepolymers with multifunctional cinnamate and bisphenol Atype cinnamate groups that could perform photodimerization without photoinitiators were synthesized by the reaction of t-cinnamic acids (CAs) and epoxy resins. Their photocure reaction rates and the extent of reaction conversion were measured with Fourier transform infrared spectroscopy, and these increased with the intensity of UVirradiation. The experimental data of these reaction rates showed the characteristics of nth-order kinetics reaction, and all kinetic constants of each photoreactive polymer with this equation were summarized. Although the GTR-1800-HCA and KWG1-EP-HCA with hydroxyl group substituted cinnamate showed lower reaction conversion rates and rate constant than GTR-1800-CA and KWG1-EP-CAwith an unsubstituted cinnamate group, GTR-1800-MCAand KWG1-EP-MCAwith methoxy group substituted cinnamate showed similar and higher reaction conversion rates than the former, respectively. These results were explained in terms of segmental mobility for photopolymerization by molecular interactions.

• Journal of Periodontal and Implant Science
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• v.26 no.2
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• pp.350-355
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• 1996

The present study was performed to evaluate the amount of bony regeneration following the guided tissue regeneration(GTR). Re-entry procedure has been performed at 1 year following the GTR with Gore-tex membranes on the furcal defects and the amount of bony regeneration was measured. Sites treatedwith open flap procedures were used as controls. The results reveated that significant amount of bone could be regenerated through the GTR procedures compared with convention flap procedures.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.967-987
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• 1996

The present study was to evaluate the healing patterns of guided tissue regeneration( GTR) using resorbable $Vicryl^{(R)}$(polyglactin 910) mesh and nonresorbable expanded polytetrafluoroethylene(ePTFE) membrane with or without bone grafting using autogeneous bone and demineralized freeze-dried bone allograft(DFDBA) in the grade II furcation defects. Mucoperiosteal flaps were reflected buccally in the mandibular 2nd, 3rd and 4th premolar areas and furcation defects were created surgically by removing $5{\times}6mm$ alveolar bone in 4 dogs. Root surfaces were thoroughly debrided of periodontal ligament and cementum, and notches were placed on root surface at the most apical bone level. In the right and left mandibular quadrant, each tooth was received $Vicryl^{(R)}$ mesh(ACE Surgical Supply Co., USA) only, $Vicryl^{(R)}$ mesh with DFDBA, $Vicryl^{(R)}$ mesh with autogeneous bone grafts, ePTFE membrane($Core-tex^{(R)}$ membrane, W.L. Gore & Associates Inc., USA) only, ePTFE membrane with DFDBA or ePTFE membrane with autogeneous bone grafts. For the fluorescent microscopic examination, fluorescent agents were injected at 2, 4 and 8 weeks after surgery. Four weeks after surgery, 2 dogs were sacrificed and ePTFE membranes were removed from remaining 2 dogs, which were sacrificed at 12 weeks after surgery. Undecalcified tissues were embedded in methylmethacrylate and $10{\mu}m$ thick sections were cut in a buccolingual direction. These sections were stained with hematoxylin-eosin stain and Masson's trichrome stain, and evaluated by descriptive histology and linear measurements. The results were as follows : 1) $Vicryl^{(R)}$ mesh group showed less connective tissue attachment than ePTFE membrane group. 2) The combination of GTR using $Vicryl^{(R)}$ mesh and osseous grafts resulted in new attachment and new bone formation more than GTR using $Vicryl^{(R)}$ mesh only. 3) GTR using ePTFE membrane, with or without osseous grafts, enhanced periodontal regeneration. 4) Root resorption and dentoalveolar ankylosis were observed in the areas treated with the combination of GTR and DFDBA. It was suggested that the effect of adjunctive bone grafting in GTR procedure depends on the materials and the physical properties of barrier membranes. $Vicryl^{(R)}$ mesh performed a barrier function and the use of adjunctive bone grafting may enhance the periodontal regeneration.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.117-128
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• 1997

Using barrier membrane, guided bone regeneration(GBR) and guided tissue regeneration(GTR) of periodontal tissue are now widely studied and good results were reported. In bone regeneration, not all cases gained good results and in some cases using GTR, bone were less regenerated than that of control. The purpose of this study is to search for the method to improve the success rate of GBR and GTR by examination of the cause of the failure. For these study, rats and beagle dogs were used. In rat study, 5mm diameter round hole was made on parietal bone of the rat and 10mm diameter of bioresorbable membrane was placed on the bone defects and sutured. In 1 ,2, 4 weeks later, the rats were sacrificed and Masson-Trichrome staining was done and inspected under light microscope for guided bone regeneration. In dog study, $3{\times}4mm^2$ Grade III furcation defect was made at the 3rd and 1th premolar on mandible of 6 beagle dogs. The defects were covered by bioresorbable membrane extending 2-3mm from the defect margin. The membrane was sutured and buccal flap was covered the defect perfectly. In 2, 4. 8 weeks later. the animals were sacrificed and undecalcified specimens were made and stained by multiple staining method. In rats. there was much amount of new bone formation at 2 weeks. and in 4 weeks specimen, bony defect was perfectly dosed and plenty amount of new bone marrow was developed. In some cases, there were failures of guided bone regeneration. In beagle dogs, guided tissue regeneration was incomplete when the defect was collapsed by the membrane itself and when the rate of resorption was so rapid than expected. The cause of the failure in GBR and GTR procedure is that 1) the membrane was not tightly seal the bony defects. If the sealing was not perfect, fibrous connective tissue infiltrate into the defect and inhibit the new bone formation and regeneration. 2) the membrane was too tightly attached to the tissue and then there was no space to be regenerated. In conclusion, the requirements of the membrane for periodontal tissue and bone regeneration are the biocompatibility, degree of sealingness, malleability. space making and manipulation. In this animal study. space making for new bone and periodontal ligament, and sealing the space might be the most important point for successful accomplishment of GBR and GTR.

• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.181-192
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• 2007

Periodontal surgery as part of the treatment of periodontal disease is mainly performed 1) to gain access to diseased areas for adequate cleaning; 2) to achieve pocket reduction or elimination; and 3) to restore the periodontal tissues lost through the disease; i.e., a new attachment formation of periodontal regeneration. To accomplish the latter, often referred to as the ultimate goal of periodontal therapy, a number of surgical procedures have been advocated throughout the years. Clinical studies have demonstrated that considerable gain of clinical attachment and bone can be achieved following guided tissue regeneration (GTR) therapy of intrabony defects. The aim of this study was to analyse the radiographic bone changes 2-year after GTR using a bone graft material and nonresorbable membrane. Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients had clinical and radiographic evidence of intrabony defect(s), 33 sites of 30 patients aged 32 to 56 (mean age 45.6) were treated by GTR with a bone graft material and nonresorbable membrane. Baseline and 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, defect depth, defect angle, bone graft materials) using the paired t-test were examined. We observed $2.86{\pm}1,87mm$ of bone fill, $065{\pm}0.79mm$ of crestal resorption, $3.49{\pm}2.11mm$ of defect resolution, and $44.42{\pm}19.51%$ of percentage of defect resolution. Mandible, deeper initial defect depth, narrower initial defect angle showed greater bone fill, defect resolution, and % of defect resolution. But no difference was observed between xenograft and allograft. Outcome of GTR as a therapy of intrabony defect was better than other therapy, but herein, good oral hygiene maintenance as a anti-infective treatment and periodic recall check of patients are essential.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.321-340
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• 1995

The regeneration of destructed periodontal tissues is one of the ultimate objectives of periodontal therapy. Guided tissue regeneration technique was developed for the ideal regeneration of periodontal tissues. In order to investigate the role of fibronectin, laminin and tenascin in the regenerating process of periodontal tissues, the expanded PTFE barrier membranes(Gore Associates, USA) removed from the patients who had been treated by guided tissue regeneration(GTR) and guided bone regeneration(GBR) techniques were fixed in neutral formalin for 6-24 hours, embedded with paraffin, sectioned at $4-6{\mu}m$ in thickness, and immunohistochemically processed by Avidin-Biotin peroxidase complex method for detecting fibronectin, laminin and tenascin. Monoclonal mouse anti-human fibronectin antibody(Oncogene Science, USA., 1:100), monoclonal mouse anti-human laminin antibody(Oncogene Science, USA., 1:50) and mouse anti-human tenascin antibody(Oncogene Science, USA, 1:10) were used as primary antibodies. The light microscopic findings were as follows: (1) The distribution of fibronectin, laminin and tenascin was various according to the area of barrier membranes. (2) The distribution of fibronectin in case of GBR was extensive in the tissue on the outer surface of barrier membranes, and rare in the intervening space and on the inner surface. In case of GTR it was extensive on the outer surface and in the intervening space, and rare on the inner surface. (3) The distribution of laminin was rare in the tissue on the outer, the inner surface and intervening space of barrier membranes, regardless of GBR or GTR. (4) In case 'of GBR rare distribution of tenascin was observed on the outer surface only, except the inner surface and the intervening space of barrier membranes. In case of GTR the distribution of tenascin was extensive in the tissue on the outer surface, rare in intervening space and the inner surface. The results suggest that fibronectin, laminin and tenascin may play a important role in the regenerating process of periodontal tissue, and they may affect the outcome of healing.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.407-417
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• 1995

In order to evaluate the effect of platelet-derived growth factor(PDGF-BB) and guided tissue regeneration(GTR) technique on the regeneration of destructed periodontal tissue,intentional through-and-through furcation defects(4mm in height) were made on both mandibular 2nd and 4th premolars of 8 adult male dogs(30-40lb). Experimental group 1 was composed of the premolars that were treated by only topical application of PDGF-BB with 0.05M acetic acid without any barrier membrane. Experimental group 2 was composed of the premolars that were treated by GTR with expanded polytetrafluoroethylene membrane(ePTFE : Gore-tex periodontal material, USA). Experimental group 3 was composed of the premolars that were treated by GTR with ePTFE after topical application of PDGFBE. Control group was composed of the premolars that were treated by coronally positioned flap operation only without use of PDGF-BB and ePTFE membrane. All ePTFE membranes were carefully removed 4 weeks after regenerative surgery, and all experimental animals were sacrificed 8 weeks after regenerative surgery. The light microscopic findings were as follows ; (1) In experimental group 1, rapid new bone formation along the-root surface with multiple ankylosis and root resorption by multinucleated giant cells, and dense connective tissue in the central portion of the furcation defects were observed. (2) In experimental group 2, it was observed that the furcation defects were filled with newly formed bone, Sharpey's fibers were embedded into new cementum on root dentin of furcation fornix area, but the central portion and the area under furcation fornix were still filled with dense connective tissue. (3) In experimental group 3, the furcation defects were regenerated with newly formed dense bone and regular periodontal ligament with Sharpey's fibers embedded into newly formed cementum and bone underneath fornix area. (4) In control group, unoccupied space, apical migration of epithelium, dense infiltration of inflammatory cells in subepithelial connective tissue in relation to heavy plaque accumulation, and root resorption by inflammatory reaction were shown, but any new cementum formation on resorbed dentin surface could not be observed. The present study demonstrated that the combined therapy of PDGF-BB and GTR could enhance the regeneration of destructed periodontal tissue.

• Journal of Auto-vehicle Safety Association
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• v.7 no.3
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• pp.14-18
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• 2015

Toughened glass is known to have about four times larger external impact resistance than that of original glass. This study is aimed to verify that ceramic-printed toughened glass does not meet of GTR(Global Technical Regulations) No. 6 and its strength is lower than that of original glass through tests. The tests were conducted on the test pieces of original glass, toughened glass, and ceramic-printed toughened glass from five glass manufacturers. In Test 1, a 227g steel ball was dropped from a height of 2 meters, and damage was checked according to the test method of GTR No. 6. In Test 2, a steel ball was freely dropped from different heights and limited damage height was determined. In the result of Test 1 according to the test method of GTR No. 6, while all five test pieces of toughened glasses were not damaged, all the ceramic-printed toughened glass from the five manufacturers were damaged. In the result of Test 2, none of the five test pieces of toughened glass were damaged by a 10m ball drop, meanwhile, the original glasses were damaged by an average of 3m ball drop. And the results of the tests show that the ceramic-printed toughened glass does not have the features of toughened glass due to its very low strength. Therefore, this study contributes to the safety of consumers by considering the GTR No. 6, and by revising the toughened glass test method.