There has been many researches aimed at reinforcing the strength of resin, and these have led to the development and use of numerous materials in recent years. A case in point, is the recent development of plasma-treated polyyethylene fiber which has been used mainly in fixed provisional restoration to reduce the incidence of fractures. This study aims at assessing whether plasma-treated polyethylene fiber as applied to composite resin is effective in increasing the flexural strength and how applied portions affect this. Twenty-four applied and eight unapplied composite resin bars were fabricated. Twenty-four applied specimens were divided into three groups. Plasma treated polyethylene fiber was applied to the groups each with different portions of composite resin. In the first group, plasma-treated polyethylene fiber was not applied. In the second group, fiber was applied to the compression side of composite resin. Fiber was applied to the tension side in the third group, while fiber was embedded in the tension side of the compositeresin in the fourth group. Each specimen was tested by use of a three-point bending strength test with an instron testing machine, and the flexural strength was calculated. The following results were obtained. : 1. Under the conditions of this study, the third and fourth groups demonstrated a statistically greater flexural strength compared to the first and second groups. 2. But there was no statiscally significant difference, not only between the first group and the second group, but also between the third group and the fourth group. Taken together, it can be concluded that plasma-treated polyethylene fiber applied to composite resin is an effective method in increasing flexural strength, and the best way of increasing the flexural strength is by application of plasma-treated polyethylene fiber to the tension side, or the embedding of same in composite resin. It must be mentioned however that this test used a static single-load test method. This method determined the maximum stresses that could be tolerated, but this might not be valid where the prediction of clinical failure is concerned. In order therfore to clinically utilize plasma-treated polyethylene fiber to reinforce the composite resin, it is suggested that a further study which considers the various loads be undertaken.
Incidence ; Plasma ; Polyethylene*

BACKGROUND: Tuberculosis is the most frequent opportunistic infection in HIV-infected patients in Korea. We examined the incidence and risk factors for tuberculosis in HIV-infected patients. METHODS: We reviewed the medical records of 143 HIV-infected patients between January 1988 and June 1997 at the Seoul National University Hospita The incidence of tuberculosis was determined by the number of new tuberculosis per 100 patients divided by a total duration of follow-up (cases/100 person- years). The incidence of tuberculosis was analyzed with respect to CD4+ lymphocyte count, status of tuberculin skin reaction, and status of delayed hypersensitivity skin reaction. RESULTS: The total duration of follow-up was 229.6 person-years. During follow-up, 22 patients developed tuberculosis [9.6 cases per 100 person-years (95% CI, 6.0 to 14.5)]. The incidence of tuberculosis according to sex and transmission route showed no significant difference. Tuberculosis occurred more frequently in patients with minimum CD4+ T lympho-cyte counts of less than 200 cells/mm3 (14.2 cases/100 person-years) than in those with higher T lymphocyte counts (3.9 cases/100 person-years) [relative risk, 4.02 (95% CI 1.32 to 12.5), P=0.009]. The incidence of tuberculosis was higher among tuberculin- positive patients [17.0 cases/100 person-years (95% CI, 9.0 to 29.0)] than among tuberculin-negative [8.0 cases/100 person-years (95% CI, 3.2 to 16.6)], but the difference was not statistically significant [relative risk, 2.35 (95% CI, 0.88 to 6.26, P=0.078)]. The rate of tuberculosis in patients with negative delayed hypersensitivity test was not significantly different from that in patients with positive results (P=0.510). CONCLUSION: The incidence of tuberculosis was 9.6 cases per 100 person-years. CD4+ lymphocyte count (<200 cells/mm3) was the most useful predictor for the development of tuberculosis in HIV patients in Korea.
Follow-Up Studies ; HIV ; Humans* ; Hypersensitivity, Delayed ; Incidence* ; Korea* ; Lymphocyte Count ; Medical Records ; Opportunistic Infections ; Risk Factors* ; Seoul ; Skin ; Tuberculin ; Tuberculosis*

To evaluate effect of coronary collateral circulation on left ventricular function in patients with acute myocardial infarction, global ejection fraction(EF), left ventricular end distolic pressure(LVEDP), peak creatine kinase(CK) level and regional wall motion were analysed and compared in 30 patients with acute myocardial infarction according to grade of coronary collateral circulation. Patients with total or near total(above 95% of diameter) occlsion of left anterior descending coronary artery without significant lesion in right coronary artery or left circumflex artery were selected and divided into 3 groups according to the degree of collateral circulation on coronary angiography, to be compared by the index of ejection fraction, peak creatine kinase level, left ventricular and diastolic pressure and regional wall motion. The result are as following : 1) There were no statistically significant differences in ejection fraction, peak creatine kinase level, left ventricualr and diastolic pressure among the groups. 2) Regional wall motion of infarct related area of G2+3 group(adequate collateral) were better than that of G0(no collateral) group(p<0.05). Therefore, adequate coronary collateral circulation in acute myocardial infarction is thought to have beneficial effect on left ventricular function especially in regional wall motion of infarct related area.
Arteries ; Blood Pressure ; Collateral Circulation* ; Coronary Angiography ; Coronary Vessels ; Creatine ; Creatine Kinase ; Humans ; Myocardial Infarction* ; Ventricular Function, Left*

The incidence and the nature of visual involvement in Friedreich's ataxia who showed progressive visual impairment a few years before developing characteristic clinical manifestations of Friedreich's ataxia. The progress of disease in this case suggests that visual involvement may be from the same pathogenetic mechanism of peripheral nervous system in Friedreich's ataxia.
Friedreich Ataxia* ; Incidence ; Optic Atrophy* ; Peripheral Nervous System ; Vision Disorders

OBJECTIVES: To assess the relationship between ST segment elevation during exercise testing and coronary artery disease. METHODS: Treadmill exercise electrocardiography and coronary angiography were performed in 137 patients with angina with no Q waves. The J point elevation of > 0.03mV(0.3mm) measured from baseline, the elevation of ST segment at 80msec. from J point(ST80) measured larger in lead V1than in aV1, or both the elevation of ST segment at J point and at ST80 developed earlier than or concomitantly with ST depression were considered as abnormal responses. RESULTS: 1) There was no clinical significance of ST elevation in lead aV1. 2) Exercise-induced ST elevation in lead V1occurred in 29 of 137 patients with angina. 3) Abnormal St elevation in V1was detected in 26 of 86 patients with coronary artery disease, for a specificity of 98%. The patients with left anterior descending coronary artery or left main coronary artery stenosis were observed in 3 of 5(60%) patients with single-vessel disease, in 7 of 9(79%) with two-vessel disease, and in 9 of 10(90%) with three-vessel disease. 4) The standard ST depression yielded a specificity of 55% in the patients with isolated or predominant ST depression in inferior leads(II. III, and aVF) and of 81% in the patients with isolated or predominat ST depressin in precordial leads(p<0.001). 5) Abnormal exercise-induced ST elevation in V1was detected in 13 of 39(33%) patients with isolated or predominat ST depression in inferior leads and yielded a specificity of 94% for coronary artery disease. CONCLUSION: Abnormal ST segment elevation in V1may increase the specificity in isolated or predominat ST segment depression in inferior leads and may predict left anterior descending or left main coronary artery disease.
Coronary Angiography ; Coronary Artery Disease* ; Coronary Stenosis ; Coronary Vessels* ; Depression ; Electrocardiography ; Exercise Test* ; Hexamethonium ; Humans ; Sensitivity and Specificity

PURPOSE: A retrospective study was undertaken to determine the role of conventional radiotherapy with or without surgery for treating a supraglottic carcinoma in terms of the local control and survival. MATERIALS AND METHODS: From Jan. 1986 to Oct. 1996, a total of 134 patients were treated for a supraglottic carcinoma by radiotherapy with or without surgery. Of them, 117 patients who had completed the radiotherapy formed the base of this study. The patients were redistributed according to the revised AJCC staging system (1997). The number of patients of stage I, II, III, IVA, IVB were 6 (5%), 16 (14%), 53 (45 %), 32 (27%), 10 (9%), respectively. Eighty patients were treated by radical radiotherapy in the range of 61.2~79.2 Gy (mean : 69.2 Gy) to the primary tumor and 45.0~93.6 Gy (mean : 54.0 Gy) to regional lymphatics. All patients with stage I and IVB were treated by radiotherapy alone. Thirty-seven patients underwent surgery plus postoperative radiotherapy in the range of 45.0~68.4 Gy (mean : 56.1 Gy) to the primary tumor bed and 45.0~59.4 Gy (mean : 47.2 Gy) to the regional lymphatics. Of them, 33 patients received a total laryngectomy (+-lymph node dissection), three had a supraglottic horizontal laryngectomy (+-lymph node dissection), and one had a primary excision alone. RESULTS: The 5-year survival rate (5YSR) of all patients was 43%. The 5YSRs of the patients with stage I+I, III+V were 49.9%, 41.2%, respectively (p=0.27). However, the disease-specific survival rate of the patients with stage I (n=6) was 100%. The 5YSRs of patients who underwent surgery plus radiotherapy (S+T) vs radiotherapy alone (RT) in stage II, III, IVA were 100% vs 43% (p=0.17), 62% vs 52% (p=0.32), 58% vs 6% (P<0.001), respectively. The 5-year actuarial locoregional control rate (5YLCR) of all the patients was 57%. The 5YLCR of the patients with stage I, II, III, IVA, IVB was 100%, 74%, 60%, 44%, 30%, respectively (p=0.008). The 5YLCR of the patients with S+T vs RT in stage II, III, IVA was 100% vs 68% (p=0.29), 67% vs 55% (p=0.23), 81% vs 20% (P<0.001), respectively. In the radiotherapy alone group, the 5YLCR of the patients with a complete, partial, and minimal response were 76%, 20%, 0%, respectively (P<0.001). In all patients, multivariate analysis showed that the N-stage, surgery or not, and age were significant factors affecting the survival rate and that the N-stage, surgery or not, and the ECOG performance index were significant factors affecting the locoregional control. In the radiotherapy alone group, multivariate analysis showed that the radiation response and N-stage were significant factors affecting the overall survival rate as well as locoregional control. CONCLUSION: In early stage supraglottic carcinoma, conventional radiotherapy alone is an equally effective modality compared to surgery plus radiotherapy and could preserve the laryngeal function. However, in the advanced stages, radiotherapy combined with concurrent chemotherapy for laryngeal preservation or surgery should be considered. In bulky neck disease, all the possible planned neck dissections after induction chemotherapy or before radiotherapy should be attempted.
Drug Therapy ; Humans ; Induction Chemotherapy ; Laryngectomy ; Multivariate Analysis ; Neck ; Neck Dissection ; Radiotherapy* ; Retrospective Studies ; Survival Rate

The goal of operation in spondylolisthesis is improving radiculopathy and relieving lower back pain preventing further progression of the slip, through decompression of neural elements and fusion of spinal pseudoarthrosis, respectively. The author performed the posterior lumbar interbody fusion technique using a Threaded Fusion Cage(T.F.C.) for 41 patients as the surgical treatment for mild spondylolisthesis. All patients enrolled in the study were implanted with a T.F.C. at a single unstable level. We have investigated the outcome results for at least one year(mean 25.8 months). Of these patients 95% have shown solid fusions. Using the Prolo scale for economic and functional rating, the combined results of excellent, good score is 51%, but clinically symptomatic improvement is 66%. Therefore, posterior lumbar interbody fusion using T.F.C. was useful in treatment of mild degree spondylolisthesis.
Decompression ; Follow-Up Studies* ; Humans ; Low Back Pain ; Pseudarthrosis ; Radiculopathy ; Spondylolisthesis*

The authors are reporting 16 cases of ossification of the thoracic ligamentum flavum. Thoracic ossified ligamentum flavum cause myelopathy as a result of pressure on the spinal cord and nerve roots. The prominent symptoms were numbness of the foot or leg, motor weakness, sphincter disturbance and exaggerated tendon reflexes. The male to female ratio was 13:8 and the 5th decade was the most prevalent age group. The predominant regions involved were T9-T10 and T10-T11. Total larminectormy was performed in all patients and the prognosis was good in most cases. The thoracic ossified ligamentum flavum and neurologic disorders due to compression of the thoracic vertebrae by other diseases do not show much of a difference in terms of symptoms. In the past, due to the lack of knowledge of this disease, treatment was performed inapproapriately. However, at the present, with the improvement of CT and MRI and the increased recognition of this disease we believe that good prognosis can be made if appropriate treatment is delivered at the time of diagnosis.
Diagnosis ; Female ; Foot ; Humans ; Hypesthesia ; Laminectomy ; Leg ; Ligamentum Flavum* ; Magnetic Resonance Imaging ; Male ; Nervous System Diseases ; Prognosis ; Reflex, Stretch ; Spinal Cord ; Spinal Cord Diseases ; Thoracic Vertebrae

BACKGROUND: To assess the risk of hospital outbreak and to guide immunization policy, seroprevalences of antibody to measles, rubella, and varicella-zoster were determined in hospital personnel. METHODS: A cross-sectional study of 290 workers in Seoul National University Hospital was conducted in June 1995. IgG antibody status was determined with commercially available enzyme linked immunosorbent assay (Behring Enzygnost; IgG kit). RESULTS: Seropositive rates of measles, rubella and varicella-zoster were 95.6%, 87.9% and 96.2%, respectively. There was no statistical difference in seropositive rate according to historical information. CONCLUSION: These results suggest potential for hospital outbreak of measles or varicella-zoster, especially of rubella. Immunization policy will be needed in hospital personnel.
Antibodies* ; Cross-Sectional Studies ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunization ; Immunoglobulin G ; Measles* ; Personnel, Hospital* ; Prevalence* ; Rubella* ; Seoul ; Seroepidemiologic Studies

Although anterior cervical plates provide excellent fixation for the anterior column, the potential risk for injury to the spinal cord or soft tissue has been the reason why they have not gained universal acceptance, new angled locking screw was designed to avoid such surgical complications. We are intending of anterior cervical fusion by means of new angled locking screw Orion Plate and also suggest that Orion Plate System is mandatory for reducing technical demands and late instrumentation failure.
Spinal Cord ; Spine*