2.Influence of Thickness of Empress 2 Ceramic on Fracture Strength.
Jung Woo KOH ; Jae Ho YANG ; Sun Hyung LEE
The Journal of Korean Academy of Prosthodontics 2000;38(4):446-460
All ceramic restorations have had a more limited life expectancy than metal ceramic crowns because of their lower strength. The relatively lower strength has limited the use of all-ceramic crowns to the areas where occlusal loads are lower. Therefore many researches have been done to increase the strength of all-ceramic crowns. IPS Empress 2 is a new type of lithium disilicate glass-ceramic with enhanced physical characteristics which has been in use clinically since 1998. Previous researches reported that the flexural strength of all-ceramic material was greater than 300MPa, and all-ceramic crowns can be used in staining or layering technique. The objective of this study was to investigate the influence of the thickness of IPS Empress 2 ceramic on fracture strength. Both staining technique and layering technique was investigated. Vita VMK was used as control. For all three groups, five specimens each of 0.8mm, 1.0mm, 1.4mm, 1.8mm, and 2.2mm thickness (a total of 75 specimens) were prepared. Control group: Vita VMK Porcelain specimens were prepared with dentine ceramic and liquid glazing was done. Group I: IPS Empress 2 were prepared with staining technique and stained twice and glazed once. Group II : IPS Empress 2 were prepared with layering technique and glazed after wash firing. The thickness and diameter of the specimen were measured and controlled after specimen preparation. Biaxial Flexure Test (ASTM Standard F394-78) was adopted as this test method produces results least affected by the edge condition of the specimens. Fracture strength was measured with Instron Universal Testing Machine. Conclusions are as follow : 1. The fracture strength was increase in order of control group, test group I, test group II. 2. Fracture strength of the group I(Empress 2 Staining) was 65.54 N in 0.8mm, 155.2 N in 1.0mm, 233.5 N in 1.44mm, 434.5 N in 1.8mm, and 600.1 N in 2.2mm. 3. Fracture strength of the group II (Empress 2 Layering) was 190.0 N in 0.8mm, 283.5 N in 1.0mm, 437.2 N in 1.4mm, 732.0 N in 1.8mm, and 1115.0 N in 2.2mm. 4. No statistical difference was found in flexural strengths according to thickness in a specified group(p>0.05).
Ceramics*
;
Crowns
;
Dental Porcelain
;
Dentin
;
Fires
;
Life Expectancy
;
Lithium
3.The Expression of L-type Calcium Channel mRNA by the Concentrations of Glucose on the Cell Proliferation in Cultured OLETF Rat Aortic Vascular Smooth Muscle Cells.
Hyung Joon YOO ; Young Jung CHO ; Hong Woo NAM
Journal of the Korean Geriatrics Society 2004;8(4):191-195
BACKGROUND: The proliferation of vascular smooth muscle cell(VSMC) is a part of the major pathogenic mechanism for atheroscle- rosis. It has been reported that L-type calcium channel plays a role in the VSMC proliferation in diabetic rats. But there is a little study results about the association between L-type calcium channel and VSMC proliferation by glucose concentrations in culture media. So we examined the association between voltage-dependent L-type calcium channel of VSMCs and the proliferative activity of vascular smooth muscle cells. METHODS: Rat aortic VSMCs were isolated from the aorta of OLETF rat by enzyme method. VSMCs were cultured in various concentrations of glucose(5.5, 25 mM). The VSMCs(1x104 cells in 24-well plates) were incubated in the presence of Bay K 8644 (10-6M) with/without verapamil(10-6M) for 48 hours. Then the proliferation was assessed by MTT(methylthiazole tetrazolium) assay and expression of L-type calcium channel mRNA was measured by RT-PCR. RESULTS: The proliferative ability and the expression of L-type calcium channel of cultured VSMCs were increased dose-dependently by the glucose concentrations(p<0.05). Bay K 8644 enhanced the proliferation of VSMC and verapamil blocked the incremental effects induced by Bay K 8644. CONCLUSION: These results suggest that L-type calcium channel may play a role in VSMC proliferation of OLETF rat.
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
;
Animals
;
Aorta
;
Calcium Channels, L-Type*
;
Cell Proliferation*
;
Culture Media
;
Glucose*
;
Muscle, Smooth, Vascular*
;
Rats
;
Rats, Inbred OLETF*
;
RNA, Messenger*
;
Verapamil
4.The Effects of Dimethly Sulfoxide and Sodium thiosulfate for the Prevention of Tissue Necrosis due to Extravasation of Mitomycin-C.
Sang Hyun WOO ; Byung Cheol CHOI ; Ki Hyung KIM ; Jung Hyun SEUL ; Tae Eun JUNG
Yeungnam University Journal of Medicine 1996;13(2):243-250
Extravasation of toxic chemotherapeutic 'agents cause severe skin ulceration and necrosis which often need secondary surgical intervention. Still, there were not established antidote agent in case of extravasation with mitomycin-c. Dimethyl sulfoxide is known as an effective chemical scavenger of toxic hydroxyl free radical and sodium thiosulfate also was demonstrated significant protector from mitomycin-c induced ulceration by a few experimental studies. Author investigated necrotic area of mitomycin-c injected site and compare to the effectiveness of topical treatment with dimethyl sulfoxide and intradermal injection of sodium thiosulfate according to starting times, forty five mice were divided into 3 groups. Control group(n=5) had no treatment after subcutaneous injection of mitomycin-c. Experimental group I and 11 were 20 mice treated dimethyl sulfoxide and sodium.
Animals
;
Dimethyl Sulfoxide
;
Injections, Intradermal
;
Injections, Subcutaneous
;
Mice
;
Mitomycin*
;
Necrosis*
;
Skin Ulcer
;
Sodium*
;
Ulcer
5.A Case of Polyarteritis Nodosa Combined with Dilated Cardiomyopathy.
Hee Jung CHOI ; Seong Ae JUNG ; Eun Young LEE ; Hae Kyung JUNG ; Gil Ja SHIN ; Woo Hyung LEE
Korean Circulation Journal 1994;24(4):668-674
Polyarteritis nodosa is systemic necrotizing vasculitis of medium and small-sized arteries and results in variable manifestations due to ischemia of the involving organs. Diagnosis can either be made pathologically by demonstrating necrotizing vasculitis of arteries or angiographycally by demonstrating small arterial aneurysm. We experienced a case of PAN with dilated cardiomyopathy, confirmed by clinical feature, renal biopsy, angiography and echocardiography.
Aneurysm
;
Angiography
;
Arteries
;
Biopsy
;
Cardiomyopathy, Dilated*
;
Diagnosis
;
Echocardiography
;
Ischemia
;
Polyarteritis Nodosa*
;
Vasculitis
6.Cloning, Sequencing and Expression in Escherichia coli of Herpes simple virus Type-1 Thymidine Kinase Gene.
Hyung Boan LEE ; Jung Woo KIM ; Hyun KANG ; Sung Chul CHA
Journal of the Korean Society of Virology 1998;28(3):215-224
Cloning, sequencing and expressing in E. coli of the thymidine kinase (TK) gene of Herpes simplex virus type-1 (HSV-1) strain F was investigated. The TK gene, located in the BamHI 3.74 kb DNA flagment of the plasmid PHLA-12, was amplified by polymerase chain reaction (PCR). The 1,131 kb PCR product was cloned into the BamHI and BglII sites of pQE-30, and named pQE-TK recombinant. The TK gene was subcloned into the BamHI and BglII sites of pQE-30, and named pQE-TK recombinant. The nucleotide sequence of the 1,131 kb TK gene was determined, and the GC content was 65.13%. There were deduced 367 amino acid residues with a total molecular weight of 43 kDa. The weight was confirmed by the protein produced by E. coli M15/pQE-TK on the SDS-PAGE and Western blot. The production of the TK protein in the IPTG induced cells was measured over 4 h. At the end of 1, 2 and 3 h the level increased by 146,204 and 242%, respectively. The amount of the protein at the highest fraction Purified with Ni-NTA resin chromatography was 0.68 ug Per ml. The soluble state TK protein was present in the cytoplasm. In these results the F strain was different in base sequence and amino acid sequence from that of the CL101 strain, which caused difference in their strains.
Amino Acid Sequence
;
Base Composition
;
Base Sequence
;
Blotting, Western
;
Chromatography
;
Clone Cells*
;
Cloning, Organism*
;
Cytoplasm
;
DNA
;
Electrophoresis, Polyacrylamide Gel
;
Escherichia coli*
;
Escherichia*
;
Herpesvirus 1, Human
;
Isopropyl Thiogalactoside
;
Molecular Weight
;
Plasmids
;
Polymerase Chain Reaction
;
Simplexvirus
;
Thymidine Kinase*
;
Thymidine*
7.Circadian Variation of Ventricular Premature Complex in Hypertension and Ischemic Heart Disease Patients.
Seung Jung KIM ; Si Hoon PARK ; Gil Ja SHIN ; Woo Hyung LEE
Korean Circulation Journal 1995;25(3):581-588
BACKGROUND: Circadian rhythms have been described for acute myocardial infarction, sudden cardiac death, cerebrovascular disease, ischemic heart disease, and ventricular arrhythmia. Most of studies reported that the frequency of ventricular permature contractions(VPC's) shows a peak in day time. We tried to see that the circadian rhythm of VPC's in hypertension and ischemic heart disease(IHD) patients. And we will also studied the relationship between heart rate and frequencey of VPC's. METHOD: Twenty four hour holter monitoring was performed in hypertensive patients (N=23), ischemic heart disease patients(N=25), and normal control group(N=30). We tested the circadian pattern of VPC's and heart rates and the relationships of the frequency of VPC's and heart rates. RESULT: In hypertension group, a peak incidence of heart rate is between 5 and 8 P.M., in ischemic heart disease group, between 3 and 6 P.M.. In control group, the heart rate shows a peak beteen 1 and 3 P.M.. The frequency of VPC's in hypertension group shows the first peak between 4 and 10 P.M., and the second peak beteen 7 and 10 A.M.. In ischemic heart disease group, they show a peak between 2 and 8 P.M..In control group, there was no circadian variation for the frequency of VPC;s. Both in hypertension and IHD patients group, there was significant correlation between the frequency of VPC's and the heart rates. CONCLUSION: It seemed that VPC' were more frequently occurred in relation to the increase of heart rate in the afternoon, in hypertensive and ischemic heart disease patients.
Arrhythmias, Cardiac
;
Circadian Rhythm
;
Death, Sudden, Cardiac
;
Electrocardiography, Ambulatory
;
Heart
;
Heart Rate
;
Humans
;
Hypertension*
;
Incidence
;
Myocardial Infarction
;
Myocardial Ischemia*
;
Ventricular Premature Complexes*
8.The Role of Insulin Resistance as a Risk Factor of Coronary Artery Disease.
Sung Ae JUNG ; Si Hoon PARK ; Gil Ja SHIN ; Woo Hyung LEE
Korean Circulation Journal 1996;26(1):35-43
BACKGROUND: Established risk factors for coronary artery disease include smoking, hypertension, diabetes mellitus and hypercholesterolemia. However, these account for less than 50% of the actual incidence of coronary artery disease and the importance of other risk factors is being increasingly realized. It has been known that insulin resistance associated with hyperinsulinemia is a pivotal link to several risk factors of coronary artery disease, including hypertension, glucose intolerance, dyslipidemia and obesity. Recently both experimental and clinical studies have produced evidence suggesting that high plasma insulin level may promote the development of atherosclerotic vascular diseasa. Several prospective studies showed independently that high plasma insulin is associated with an increased risk of major coronary artery disease. In our study, plasma glucose, insulin and C-peptide level were determined with oral glucose tolerance test to assess the insulin resistance or hyperinsulinemia as a risk factory of coronary artery disease. METHOD: From September 1993 to April 1995, after excluding patients with hypertension, diabetes mellitus, hypercholesterolemia and obesity, 17 patients with significant coronary artery stenosis and 10 control subjects with normal coronary finding were selected among the 226 patients who undertook coronary angiography. In the 17 cases(M:F=15:2) of coronary artery disease group, the mean age was 54+/-10 years, and in the 10 cases(M:F=8:2) of control group, 51+/-9 years. All were matched for age, gender and body mass index. Blood pressure, lipid and lipoprotein were measured and smoking history was assessed. Glucose, insulin and C-peptide responses to oral glucose tolerance test were also determined. RESULT: 1) There was no significant difference in systolic and diastolic and diastolic blood pressure, total-cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, ApoA and smoking history except ApoB between the subjects with coronary artery disease and normal control subjects. 2) In oral glucose tolerance test, the plasma glucose levels were not significantly different in the two groups. plasma insulin and C-peptide levels at 60 and 120 minutes were higher in the patient group than control, but the results lack statistical significance. The area under the insulin curve and C-peptide curve were larger in patient group than control, but the result lack statistical significance also. CONCLUSION: Although our study dose not prove the hypothesis that insulin resistance or hyperinsulinemia is statistically an independent risk factor for coronary artery disease, this study showed the tendency of insulinresistance to be correlated with development of coronary artery disease. As this study has limitations due to small sample size, further study is required to confirm the role of hyperinsulinemia using a larger sample size.
Apolipoproteins A
;
Apolipoproteins B
;
Blood Glucose
;
Blood Pressure
;
Body Mass Index
;
C-Peptide
;
Coronary Angiography
;
Coronary Artery Disease*
;
Coronary Stenosis
;
Coronary Vessels*
;
Diabetes Mellitus
;
Dyslipidemias
;
Glucose
;
Glucose Intolerance
;
Glucose Tolerance Test
;
Humans
;
Hypercholesterolemia
;
Hyperinsulinism
;
Hypertension
;
Incidence
;
Insulin Resistance*
;
Insulin*
;
Lipoproteins
;
Obesity
;
Plasma
;
Prospective Studies
;
Risk Factors*
;
Sample Size
;
Smoke
;
Smoking
;
Triglycerides
9.Comparison of Betamethasone Concentration in Aqueous Humor Between Upper and Lower Fornix Subconjunctival Injection After Lens Delivery.
Hyung Woo KWAK ; Jung Hyoo MOON
Journal of the Korean Ophthalmological Society 1988;29(4):547-550
The purpose of this paper is to investigate the difference in concentration of 0.53% betamethasone in aqueour humor after betamethasone subconjunctival injection on upper and lower fornix after cataract extraction. A total of 8 rabbits were used. Cataract extractions were performed with the cryoprobe. After 6 hours, 0.53% betamethasone was subconjunctivally in upper fornix of the left eye and injected in lower fornix of the right eye. The control group of 3 rabbits underwent with the same procedures but the without lens delivery. the concentration of 0.53% betamethasone in aqueous humor was measured with HPLC(High Performance Liquid Chromatograph) after fine needle aspiration of aqueous humor. The results obtained were as follows. 1. In 5 eyes of the control group in 3 rabbits, 0.53%betamethasone was injected subconjunctivally on the lower fornix. The mean concentration of 0.53% betamethasone in aqueous humor was 0.544 +/- 0.0818 microgram/ml. 2. After 0.53% betamethasone subconjunctival injection on upper fornix after lens extraction, the mean concentration of 0.53% betamethasone in aqueous humor was 0.318 +/- 0.0117 microgram/ml. 3. After 0.53% betamethasone subconjunctival injection on lower fornix agter lens extraction, the mean concentration of 0.53%betamethasone in aqueous humor was 0.702 +/- 0.0332 microgram/ml. 4. The mean concentration of the betamethasone in aqueous humor after 0.53% betamethasone subconjunctival injection on lower fornix after lens extraction was significantly higher than on upper fornix(p<0.05).
Aqueous Humor*
;
Betamethasone*
;
Biopsy, Fine-Needle
;
Cataract Extraction
;
Rabbits
10.2 Cases of Bacterial Intracranial Aneurysm.
Jong Woo HAN ; Jin Myung JUNG ; Hyung Jin SHIN
Journal of Korean Neurosurgical Society 1991;20(12):1102-1109
The authors experienced 2 cases of bacterial intracranial aneurysm, the mortality of which has been reported to by very high and the management of which is controversial. Some authors have recommended observation with serial angiography during antimicrobial therapy and surgery for aneurysms that enlarge or remain patent. Others have argued for promt surgical removal. Bothof our patients had multiple aneurysms and were treated with appropriate, high-dose antibiotics, but intracerebral homorrhage(ICH) occurred during antibiotiecs treatment in both cases and they underwnet emergent operation, but both died.
Aneurysm
;
Angiography
;
Anti-Bacterial Agents
;
Humans
;
Intracranial Aneurysm*
;
Mortality