No abstract available.
Ectoderm* ; Ectodermal Dysplasia* ; Prosthodontics*

BACKGROUND: Platelet function is directly influenced by lipoproteins, and platelets from hypercholesterolemic patients display increased reactivity which is related to initiation, progression, and development of thromboembolic complications in atherosclerosis. But the exact mechanism of this effect is unclear. METHODS: In this study, total and activated numbers of platelet glycoprotein (Gp) IIb/IIIa were evaluated in twenty patients (7 men; age, 55.4+/-8.7 years) with hypercholesterolemia (plasma total cholesterol level over 240 mg/dL and normal triglyceride level) and twenty one subjects (8 men; 51.1+/-13.7 years) with normal plasma cholesterol and triglyceride levels. Flow cytometry was used to detect the binding of fluorescein isothiocyanate (FITC)-conjugated anti-CD41 or PAC1 to platelet Gp IIb<1/4>/<1/4>IIIa in whole blood. When whole blood was incubated with PAC1, platelets were also activated with adenosine diphosphate (ADP) or thrombin. RESULTS: PAC1 was more bound to unstimulated platelets from patients with hypercholesterolemia (p<0.005), and binding of PAC1 correlated significantly with plasma total cholesteol (r=0.48, p=0.002) and LDL-cholesterol (r=0.47, p=0.002) levels. Binding of PAC1 to unstimulated platelets increased as binding of anti-CD41 increased (r=0.40, p=0.01). On multivariate linear regression analysis, plasma total cholesterol level and binding of anti-CD41 were independent variables that determined binding of PAC1. After ADP- or thrombin-stimulation, binding of PAC1 to platelets and percentage of antibody positive cells were also greater in patients with hypercholesterolemia (p<0.05). There was a significant positive correlation between mean platelet volume and binding of anti-CD41 to unstimulated platelets (r=0.46, p<0.0050), but the latter was not different between hypercholesterolemia and control groups. CONCLUSION: Unstimulated platelets from patients with hypercholesterolemia had similar total number of Gp IIb/IIIa to those from control subjects, but had more activated Gp IIb/IIIa. After ADP- or thrombin-stimulation, platelet Gp IIb/IIIa was also more activated under hypercholesterolemia.
Adenosine Diphosphate ; Atherosclerosis ; Blood Platelets* ; Cholesterol ; Flow Cytometry ; Fluorescein ; Glycoproteins* ; Humans ; Hypercholesterolemia ; Linear Models ; Lipoproteins ; Male ; Mean Platelet Volume ; Plasma ; Thrombin ; Triglycerides

BACKGROUND AND OBJECTIVES: Regular aerobic exercise plays a role in the prevention of cardiovascular diseases, but the risk of primary cardiac arrest transiently increases during vigorous exercise, particularly in sedentary men. There has been a controversy regarding the effect of exercise on platelet functional behavior, which is related to the pathogenesis of coronary ischemia. We evaluated the cytoplasmic free calcium concentration of platelets in healthy men after treadmill exercise. MATERIALS AND METHOD: Five physically active (group I: age, 24.2+/-2.3 years) and five sedentary men (group II: age, 22.4+/-1.4 years) were included in this study. Platelet calcium was measured with fluorescent dye, quin2 before and after treadmill exercise. RESULTS: Platelet calcium levels were increased from 86.8+/-11.8 nM to 128.8+/-15.0 nM in group I (p<0.05) and from 102.6+/-14.4 nM to 162.4+/-26.5 nM in group II (p<0.05) immediately after exercise. Thereafter, platelet calcium levels were decreased in group I, but continuously increased in group II. At fifteen minutes after exercise, platelet calcium concentrations were significantly higher than baseline values in group II (205.8+/-53.9 nM vs 102.6+/-14.4 nM: p<0.05), but not in group I (115.2+/-15.7 nM vs 86.8+/-11.8 nM). CONCLUSION: Cytoplasmic free calcium concentration in platelets were continuosly increased after treadmill exercise in sedentary men but not in physically active men.
Blood Platelets* ; Calcium* ; Cardiovascular Diseases ; Cytoplasm* ; Exercise ; Heart Arrest ; Humans ; Ischemia ; Male*

BACKGROUND AND OBJECTIVES: Regular aerobic exercise plays a role in the prevention of cardiovascular diseases, but the risk of primary cardiac arrest transiently increases during vigorous exercise, particularly in sedentary men. There has been a controversy regarding the effect of exercise on platelet functional behavior, which is related to the pathogenesis of coronary ischemia. We evaluated the cytoplasmic free calcium concentration of platelets in healthy men after treadmill exercise. MATERIALS AND METHOD: Five physically active (group I: age, 24.2+/-2.3 years) and five sedentary men (group II: age, 22.4+/-1.4 years) were included in this study. Platelet calcium was measured with fluorescent dye, quin2 before and after treadmill exercise. RESULTS: Platelet calcium levels were increased from 86.8+/-11.8 nM to 128.8+/-15.0 nM in group I (p<0.05) and from 102.6+/-14.4 nM to 162.4+/-26.5 nM in group II (p<0.05) immediately after exercise. Thereafter, platelet calcium levels were decreased in group I, but continuously increased in group II. At fifteen minutes after exercise, platelet calcium concentrations were significantly higher than baseline values in group II (205.8+/-53.9 nM vs 102.6+/-14.4 nM: p<0.05), but not in group I (115.2+/-15.7 nM vs 86.8+/-11.8 nM). CONCLUSION: Cytoplasmic free calcium concentration in platelets were continuosly increased after treadmill exercise in sedentary men but not in physically active men.
Blood Platelets* ; Calcium* ; Cardiovascular Diseases ; Cytoplasm* ; Exercise ; Heart Arrest ; Humans ; Ischemia ; Male*

No abstract available.
Dental Implantation* ; Dental Implants* ; Osseointegration*

No abstract available.
Humans ; Interferon-alpha* ; Interferons* ; Melanoma* ; Ulcer*

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

The ideal restorative material should mimic the properties of the tissues it replaces. Dental composite resins have been used widely as restorative materials due to its advantages such as excellent esthetics and ease of manipulation. But inadequate wear resistance has been a major factor limiting the use of composite restorative materials. Improved manufacturing techniques have allowed the development of hybrid composites, with a greater percentage volume filler loading, which have improved physical an mechanical properties. However they are lacking the study wear resistance. The purpose of this study was to evaluate the wear of human enamel against ceromer by the use of a pin-on-disk type wear testers. Discs of ceromer(Targis : Ivoclar, Vivadent, Amherst. NY) and discs of type III gold alloy as a control were used for test specimens. Intact cusp of premolar and molar were used for enamel specimens. The wear of enamel was determined by weighing the cusp before and after each test, and the weight converted to volumes by average density of enamel. Surface profilometer was used to quantify wear of the ceromer and gold specimens. Vicker's hardness tester was used to evaluate the surface hardness of test specimens. The SEM was used to evaluate the wear surfaces. The results were as follows; 1. Ceromer produced less enamel wear than gold(p<0.05). 2. The wear volume of ceromer was greater than that of gold(p<0.01). 3. The hardess of ceromer was lower than that of gold, but there was no correlation between the hardness and wear of the ceromer and gold. 4. SEM analysis revealed that there were many voids and microcracks in the wear tract of ceromer. in gold group, many minute V-shaped grooves were examined.
Alloys ; Bicuspid ; Composite Resins ; Dental Enamel* ; Esthetics ; Hardness ; Hardness Tests ; Humans* ; Molar

Human epithelial cell line immortalized by Ad12-SV40 hybrid virus was transfected with plasmid containing HPV-16 via calcium-phosphate method. Subsequently, 8 clonal cell lines were obtained after G418 selection. Among these clonal cells, clonal cell-4(C-4) and clonal cell-6(G-6) showed increases of tumorigenic cellular properties such as saturation density, soft agar colony formation and cell aggregation. Morphological alteration such as appearane of foci was observed on these two clones after passage 6 and 7(50 to 55 days after transfection). When clonal cells and control cells were treated with MNNG(0.01ug/ml), both C-4 and C-6 showed increases of tumorigenic cellular properties and the level of increase was much more elevated as compared to clonal cells prior to MNNG treatment. Appearance of foci formation was observed in C-4 and C-6 after passage-6. After passage-8, control cells and all clonal cells showed morphological alterations. It seems that treatment of cells containing HPV-16 DNA with MNNG increases tumorigenic properties of the cells and expedite morphological transformations. (continue)
Agar ; Cell Aggregation ; Cell Line ; Clone Cells ; DNA ; Epithelial Cells* ; Human papillomavirus 16 ; Humans* ; Methylnitronitrosoguanidine ; Plasmids

All-ceramic restorations have become an attractive alternative to porcelain-fused-to-metal crowns. In-Ceram, and more recently IPS Empress 2 were introduced as a new all-ceramic system for single crowns and 3-unit fixed partial dentures. But their strength and marginal fit are still an important issue. This study evaluated the fracture resistance and marginal fit of three systems of 3 unit all-ceramic bridge fabricated on prepared maxillary anterior resin teeth in vitro. The 3 all-ceramic bridge systems were: (1) a glass-infiltrated, sintered alumina system (In-Ceram) fabricated conventionally, (2) the same system with copy-milled alumina cores (copy-milled In-Ceram), (3) a heat pressed, lithium disilicate reinforced glass-ceramic system (IPS Empress 2). Ten bridges of each system with standardized design of framework were fabricated. All specimens of each system were compressed at 55degree at the palatal surface of pontic until catastrophic fracture occurred. Another seven bridges of each system were fabricated with standard method. All of the bridge-die complexes were embedded in epoxy resin and sectioned buccolingually and mesiodistally. The absolute marginal discrepancy was measured with stereomicroscope at x50 power. The following results were obtained: 1. There was no significant difference in the fracture strength among the 3 systems studied. 2. The Weibull modulus of copy-milled In-Ceram was higher than that of In-Ceram and IPS Empress 2 bridges. 3. Copy-milled In-Ceram (112micrometer) exhibited significantly greater marginal discrepancy than In-Ceram (97micrometer), and IPS Empress 2 (94micrometer at P=0.05. 4. The lingual surfaces of the ceramic crowns showed smaller marginal discrepancies than mesial and distal points. There was no significant difference between teeth (incisor, canine) at P=0.05. 5. All-ceramic bridges of three systems appeared to exhibit sufficient initial strength and acceptable marginal fit values to allow clinical application.
Aluminum Oxide ; Ceramics ; Crowns ; Denture, Partial, Fixed ; Hot Temperature ; Lithium ; Tooth