1.Comparisons of the outcomes between nonstimulated cycles and clomiphene stimulated cycles in IVF & ET.
Seong Ho YIM ; Hyuck Chan KWON
Korean Journal of Obstetrics and Gynecology 1993;36(4):521-533
No abstract available.
Clomiphene*
2.Comparisons of the outcomes between nonstimulated cycles and clomiphene stimulated cycles in IVF & ET.
Seong Ho YIM ; Hyuck Chan KWON
Korean Journal of Obstetrics and Gynecology 1993;36(4):521-533
No abstract available.
Clomiphene*
3.MECHANICAL PROPERTIES OF TITANIUM CONNECTORS TREATED BY VARIOUS WELDING TECHNIQUES.
Soo Young LEE ; Ik Tae CHANG ; Seong Joo HEO ; Soon Ho YIM
The Journal of Korean Academy of Prosthodontics 1999;37(5):545-566
The use of pure titanium and titanium alloys have been increased recently in fixed, removable prosthodontics and implant fields as a framework. But when they were used for superstructures of implant of metal framework of removable prosthesis, welding is necessary to reconnect the fracture site to control the casting distortions. To overcome the difficulties in soldering the titanium due to high oxidation property, much effort have been devoted. In this study, some of mechanical properties were compared between pure titanium and Ti-6Al-4V alloy by usingl aser welding, electron beam welding technique and tungsten arc welding. Mechanical properties such as tensile strength, yield strength, elongation and microhardness were measured. And, in order to compare the effect of welding site and surrounding metal tissue according to the welding condition, SEM photographs were taken an element distribution was observed by Wave Dispersion Spectroscopy. Through analyses of the data, following results were obtained; 1. In items such as tensile strength, yield strength and elongation according to the welding techniques of pure titanium, only tungsten arc welded group showed significant lower value than other groups(P<0.05). 2. In items such as tensile strength and yield strength according to the welding techniques of Ti-6Al-4V alloy, control group and tungsten arc welded group showed significant difference among all the groups(P<0.05). 3. Ti-6Al-4V alloy exhibited significantly greater elongation than control group when the laser welding method and electron beam welding method were used, and elongation showed increasing tendency. 4. Pure titanium specimens exhibited increasing tendency of microhardness regardless of the welding technique applied, and especially tungsten arc welded group demonstrated a great increase of microhardness than parent metal. 5. There was no hardness change in laser welded group and electron bean welded group of Ti-6Al-4V ally, but in tungsten arc welded group, hardness changed greatly from parent metal to weld seam. 6. Through the metallographic examination and scanning electron microscopy, laser welding caused central fusion and recristallizations were formed and tungsten arc welding caused localized fusion to 0.3-0.7mm from the surface.
Alloys
;
Hardness
;
Humans
;
Microscopy, Electron, Scanning
;
Parents
;
Prostheses and Implants
;
Prosthodontics
;
Spectrum Analysis
;
Tensile Strength
;
Titanium*
;
Tungsten
;
Welding*
4.Intracranial Fusiform Aneurysms: It's Pathogenesis, Clinical Characteristics and Managements.
Seong Ho PARK ; Man Bin YIM ; Chang Young LEE ; Ealmaan KIM ; Eun Ik SON
Journal of Korean Neurosurgical Society 2008;44(3):116-123
OBJECTIVE: The objective of this study is to investigate clinical characteristics, management methods and possible causes of intracranial fusiform aneurysm. METHODS: Out of a series of 2,458 intracranial aneurysms treated surgically or endovascularly, 22 patients were identified who had discrete fusiform aneurysms. Clinical presentations, locations, treatment methods and possible causes of these aneurysms were analyzed. RESULTS: Ten patients of fusiform aneurysm were presented with hemorrhage, 5 patients with dizziness with/without headache, 4 with ischemic neurologic deficit, and 1 with 6th nerve palsy from mass effect of aneurysm. Two aneurysms were discovered incidentally. Seventeen aneurysms were located in the anterior circulation, other five in the posterior circulation. The most frequent site of fusiform aneurysm was a middle cerebral artery. The aneurysms were treated with clip, and/or wrapping in 7, resection with/without extracranial-intracranial (EC-IC) bypass in 6, proximal occlusion with coils with/without EC-IC bypass in 5, EC-IC bypass only in 1 and conservative treatment in 3 patient. We obtained good outcome in 20 out of 22 patients. The possible causes of fusiform aneurysms were regard as dissection in 16, atherosclerosis in 4 and collagen disease or uncertain in 2 cases. CONCLUSION: There is a subset of cerebral aneurysms with discrete fusiform morphology. Although the dissection or injury of internal elastic lamina of the cerebral vessel is proposed as the underlying cause for most of fusiform aneurysm, more study about pathogenesis of these lesions is required.
Abducens Nerve Diseases
;
Aneurysm
;
Atherosclerosis
;
Collagen Diseases
;
Dizziness
;
Glycosaminoglycans
;
Headache
;
Hemorrhage
;
Humans
;
Intracranial Aneurysm
;
Middle Cerebral Artery
;
Neurologic Manifestations
5.The study on the removal torque of the diamond like carbon coated titanium abutment screws.
Jai young KOAK ; Seong Joo HEO ; Ik Tae CHANG ; Soon Ho YIM ; Jong Yeop LEE ; Kwang Ryeol LEE
The Journal of Korean Academy of Prosthodontics 2003;41(2):128-135
STATEMENT OF PROBLEM: Implant screw loosening remains a problem in implant prosthodontics. Some abutment screws with treated surfaces were introduced to prevent screw loosening and to increase preload. DLC(Diamond Like Carbon) film has similar properties on hardness, wear resistance, chemical stability, biocompatibility as real diamond materials. PURPOSE: The purpose of this study was to investigate the effect of lubricant layer on abutment screw and to discriminate more effective method between soft lubricant and hard lubricant to prevent screw loosening. MATERIAL AND METHOD: In this study, 1mum thickness DLC was used as protective, lubricating layer of titanium screws and 3 times removal torque was measured on the abutment screws to investigate the difference in 10 coated and 10 non-coated abutment screws. RESULTS: The results indicated that the implants with DLC coating group were not more resistant to the applied force in screw loosening. At 32Ncm, the 3 times removal torque in DLC group were 27.7+/-2.89, 25.85+/-2.35 and 26.2+/-2.57. The removal torque in no-coated abutment screws were 27.85+/-4.23, 27.35+/-2.81 and 27.9+/-2.31, respectively. CONCLUSION: The lubricant layer used in this study was Diamond Like Carbon(DLC) and it have a properties of hard and stable layer. The DLC coating layer was hard enough to prevent distortion of screws in the repeated unscrewing procedure in clinical situation. The reduced friction coefficient in hard DLC layer was not effective to prevent screw loosening.
Carbon*
;
Diamond*
;
Friction
;
Hardness
;
Prosthodontics
;
Titanium*
;
Torque*
6.The Merits of Endovascular Coil Surgery for Patients with Unruptured Intracranial Aneurysms.
Seong Ho PARK ; Chang Young LEE ; Man Bin YIM
Journal of Korean Neurosurgical Society 2008;43(6):270-274
OBJECTIVE: The purpose of this study was to report the morbidity, mortality, angiographic results, and merits of elective coiling of unruptured intracranial aneurysms. METHODS: Ninety-six unruptured aneurysms in 92 patients were electively treated with detachable coils. Eighty-one of these aneurysms were located in the anterior circulation, and 15 were located in the posterior circulation. Thirty-six aneurysms were treated in the presence of previously ruptured aneurysms that had already undergone operation. Nine unruptured aneurysms presented with symptoms of mass effect. The remaining 51 aneurysms were incidentally discovered in patients with other cerebral diseases and in individuals undergoing routine health maintenance. Angiographic and clinical outcomes and procedure-related complications were analyzed. RESULTS: Eight procedure-related untoward events (8.3%) occurred during surgery or within procedure-related hospitalization, including thromboembolism, sac perforation, and coil migration. Permanent procedural morbidity was 2.2% ; there was no mortality. Complete occlusion was achieved in 73 (76%) aneurysms, neck remnant occlusion in 18 (18.7%) aneurysms, and incomplete occlusion in five (5.2%) aneurysms. Recanalization occurred in 8 (15.4%) of 52 coiled aneurysms that were available for follow-up conventional angiography or magnetic resonance angiography over a mean period of 13.3 months. No ruptures occurred during the follow-up period (12-79 months). CONCLUSION: Endovascular coil surgery for patients with unruptured intracranial aneurysms is characterized by low procedural mortality and morbidity and has advantages in patients with poor general health, cerebral infarction, posterior circulation aneurysms, aneurysms of the proximal internal cerebral artery, and unruptured aneurysms associated with ruptured aneurysm. For the management of unruptured aneurysms, endovascular coil surgery is considered an attractive alterative option.
Aneurysm
;
Aneurysm, Ruptured
;
Angiography
;
Cerebral Arteries
;
Cerebral Infarction
;
Follow-Up Studies
;
Hospitalization
;
Humans
;
Intracranial Aneurysm
;
Magnetic Resonance Angiography
;
Neck
;
Rupture
;
Thromboembolism
7.Response of osteoblast-like cells on titanium surface treatment.
Hyun Ki ROH ; Seong Joo HEO ; Ik Tae CHANG ; Jai Young KOAK ; Jong Hyun HAN ; Yong Sik KIM ; Soon Ho YIM
The Journal of Korean Academy of Prosthodontics 2003;41(6):699-713
Statement of problem. Titanium is the most important material for biomedical and dental implants because of their high corrosion resistance and good biocompatibility. These beneficial properties are due to a protective passive oxide film that spontaneously forms on the surface. Purpose. The purpose of this study was to evaluate the responses of osteoblast-like cells on different surface treatments on Ti discs. Material and Methods. Group 1 represented the machined surface with no treatment. Group 2 surfaces were sandblasted with 50microm Al2O3 under 5 kgf/cm2 of pressure. Groups 3 and 4 were sandblasted under the same conditions. The samples were treated on a titanium oxide surface with reactive sputter depositioning and thermal oxidation at 600degree C (Group 3) and 800degree C (Group 4) for one hour in an oxygen environment. The chemical composition and microtopography were analyzed by XRD, XPS, SEM and optical interferometer. The stability of TiO2 layer was studied by potentiodynamic curve. To evaluate cell response, osteoblast extracted from femoral bone marrow of young adult rat were cultured for cell attachment, proliferation and morphology on each titanium discs. Results and Conclusion. The results were as follows : 1.Surface roughness values were, from the lowest to the highest, machined group, 800degree C thermal oxidation group, 600degree C thermal oxidation group and blasted group. The Ra value of blasted group was significantly higher than that of 800degree C thermal oxidation group (P=0.003), which was not different from that of 600degree C thermal oxidation group (P<0.05). 2. The degree of cell attachment was highest in the 600degree C thermal oxidation group after four and eight hours (P<0.05), but after 24 hours, there was no difference among the groups (P>0.05). 3. The level of cell proliferation showed no difference among the groups after one day, three days, and seven days (P>0.05). 4. The morphology and arrangement of the cells varied with surface roughness of the discs.
Animals
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Bone Marrow
;
Cell Proliferation
;
Corrosion
;
Dental Implants
;
Humans
;
Osteoblasts
;
Oxygen
;
Rats
;
Titanium*
;
Young Adult
8.Aortobronchial Fistula After Chest Trauma.
Jae Hyun KIM ; Sang Ho MOON ; Sam Hyun KIM ; Pil Won SEO ; Soo Bin YIM ; Seong Sik PARK
The Korean Journal of Thoracic and Cardiovascular Surgery 2002;35(2):141-143
Few patients with traumatic aortic laceration remain undiagnosed and survive long enough to develop a chronic aneurysm. Such aneurysms are frequently asymptomatic: alternatively, they may manifest chest pain, dysphagia, bronchial irritation, or sudden death. A case of aortobronchial fistula secondary to a chronic post-traumatic aneurysm of the aortic isthmus is presented. Hemoptysis was the main sign. The affected segment of the thoracic aorta was repaired with a Hemashield patch and a left upper lobectomy was performed.
Aneurysm
;
Aorta, Thoracic
;
Chest Pain
;
Death, Sudden
;
Deglutition Disorders
;
Fistula*
;
Hemoptysis
;
Humans
;
Lacerations
;
Thorax*
9.Long-Term Results of CyberKnife Radiosurgery for Vestibular Schwannoma
Ho Joong LEE ; Chae Dong YIM ; Hyun Woo PARK ; Dong Gu HUR ; Ho Jin JEONG ; Seong Ki AHN
Journal of the Korean Balance Society 2017;16(1):23-28
OBJECTIVE: Since the 2000s, CyberKnife radiosurgery (CKRS) is either a primary or an adjunct management approach used to treat patients with vestibular schwannoma (VS). The goals of CKRS are prevention of tumor growth, preservation of cranial nerve function and prevention of new neurologic deficiencies. The aim of this study was to assess the efficacy and safety of CKRS, in terms of tumor control, hearing preservation, and complications. METHODS: Forty patients with VS underwent CKRS as a treatment modality for from January 2010 to February 2016. The long term results of 32 patients were evaluated who received CKRS as primary treatment. 8 patients presented with previously performed surgical resection. Information related to clinical history, Brain MRI and outcomes of patients with VS collected retrospectively by reviewing patient's chart and telephone survey. RESULTS: The mean tumor volume was 3.3 cm³ and the mean follow-up was 41 months. The most recent follow-up showed that tumor size decreased in 17 patients (42.5%), displayed no change in 19 patients (47.5%), and increased in 4 patients (10%). Progression-free survival rates after CKRS at 1, 3, and 5 years were 95%, 90%, and 90%. After CKRS, 13 patients experienced hearing degradation. The overall rate of preservation of serviceable hearing at the long-term follow-up was 60%. Vertigo, ataxia, and headache were improved after CKRS compared with pretreated status. But, facial weakness, trigeminal nerve neuropathy, and tinnitus were worsen. CONCLUSION: CKRS provide an excellent tumor control rate and a comparable hearing preservation rate in VS patients. Also CKRS is associated with low rate of cranial neuropathy, other complications.
Ataxia
;
Brain
;
Cranial Nerve Diseases
;
Cranial Nerves
;
Disease-Free Survival
;
Follow-Up Studies
;
Headache
;
Hearing
;
Humans
;
Magnetic Resonance Imaging
;
Neuroma, Acoustic
;
Radiosurgery
;
Retrospective Studies
;
Telephone
;
Tinnitus
;
Trigeminal Nerve
;
Tumor Burden
;
Vertigo
10.Resonance frequency analysis of impl-ants with anodized surface oxides.
Jeong Won CHOI ; Seong Joo HEO ; Ik Tae CHANG ; Jai Young KOAK ; Jong Hyun HAN ; Yong Sik KIM ; Seok Hyung LEE ; Soon Ho YIM
The Journal of Korean Academy of Prosthodontics 2004;42(3):294-300
The present experimental study was designed to address two issues. The first was to investigate whether oxidation voltage of titanium implants influenced bone tissue responses after an in vivo implantation. The second aim was to investigate secondary stability change after 1 to 3months period. Screw-shaped implants with a wide range of oxide properties were prepared by electrochemical oxidation methods, where the oxide thickness varied in the range of 3-15micrometer. The micro structure revealed pore sizes of 1-3micrometer, the crystal structures of the titanium oxide were amorphous, anatase and a mixture of anatase and rutile type. Bone tissue responses were evaluated by resonance frequency measurements that were undertaken 1 to 3months after insertion in the rabbit tibia. It was concluded that no statistical difference of RFA values was found between the groups, RFA gains after 1month and 3months were calculated.
Bone and Bones
;
Oxides*
;
Tibia
;
Titanium