Biomedical subjects

E Kawada

Publications and source records attributed to E Kawada.

At least 19 recordsLinked to original sources

PubMed2006

Influence of ascorbic acid on bonding of peroxide-affected dentin and 4-META/MMA-TBB resin.

The purpose of this study was to evaluate the tensile bond strength (TBS) to peroxide-exposed dentin. Furthermore, the effect of ascorbic acid (AA) on the bond strength of peroxide-exposed dentin was investigated. Extracted bovine dentin was exposed to 10% carbamide peroxide, 30% hydrogen peroxide, or distilled water for 30 min, then treated with 10% AA (0, 30, 90, and 180 min), and conditioned with 10% citric acid/3% ferric chloride. The polymethyl-methacrylate (PMMA) rod was bonded to the treated bovine dentin with 4-META/MMA-TBB resin. A minidumbbell-shaped bonded specimen was prepared from these bonded assemblies and the TBS was tested. The fractured surfaces were also observed with a scanning electron microscope. Exposure to peroxide before bonding significantly reduced bond strength. The application of AA to the peroxide-exposed dentin increased bond strength. On the other hand, an adverse effect of AA was found in distilled water-affected dentin. Extended resin fibers were partially seen in the peroxide-exposed dentin. In conclusion, peroxide reduced the bond strength, and the stronger the oxidation, the weaker the obtained bond. Antioxidation with AA recovered the bond strength, and this effect increased the longer the AA was applied.

Animals↗

PubMed2005

A decade-long sour-taste sensation successfully treated with a proton-pump inhibitor.

We report a case study of a 54-year-old Japanese woman who persistently suffered from a sour-taste sensation in her mouth for 10 years, and was treated with a proton-pump inhibitor (PPI). She found sour-tasting meals irritable, and after eating such meals the sour-taste sensation worsened. She also complained of eructation and regurgitation. Upper gastrointestinal (GI) endoscopy showed duodenal erosion, superficial gastritis, and erosive oesophagitis. After 2 weeks of PPI therapy (lansoprazole, 30 mg day(-1)) the sour taste subjectively decreased to 70%, and after 6 weeks the symptoms disappeared. In addition to increased sensitivity of the mouth, gastro-oesophageal reflux might have created her obstinate sour-taste sensations. It is suggested that in such cases PPI therapy should be attempted.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2004

Usefulness of FDG-PET to diagnose intravascular lymphomatosis presenting as fever of unknown origin.

Intravascular lymphomatosis (IVL) is a rare systemic disease characterized by proliferation of lymphoid cells within the lumina of small arteries, veins, and capillaries. Diagnosis requires skin, liver, lung, bone marrow, renal, meningeal, or brain vessel biopsy but is often made only when the illness has progressed or post mortem because early involvement of organs was not evident. We report a case of IVL presenting as fever of unknown origin (FUO). In this case, gallium scintigraphy and computed tomography (CT) showed no evidence of malignancy, whereas (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed increased FDG uptake in the sternum, left and right vertebra, humerus, femur, and especially ilium. The diagnosis was made on iliac bone marrow biopsy examination. FDG-PET was useful for the detection of spread of disease in a patient with IVL suffering from FUO.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2002

Effect of HEMA on bonding of Er:YAG laser-irradiated bovine dentine and 4-META/MMA-TBB resin.

The purpose of this study was to evaluate the priming effect of 2-hydroxyethylmetaclirate (HEMA) following acid treatment on resin bonding to prototype Er:YAG laser-irradiated dentine. Extracted bovine dentine following laser irradiation was acid treated by aqueous solution of 10% citric acid (10-0) or 10% citric acid/3% ferric chloride (10-3), and additionally treated with 35% HEMA. Pre-treated dentines were bonded to the polymethyl-methacrylate (PMMA) rod with 4-META/MMA-TBB resin (Super Bond C & B) and miniaturized dumbbell-shaped bonded specimens were prepared. These specimens profiled for tensile bond testing and fractured surfaces were observed by scanning electron microscopy (SEM). Cross-sections of resin-dentine interface were also examined. The HEMA treatment following acid conditioned by 10-3 or 10-0 for both laser-irradiated and non-irradiated dentines was significantly higher than that without HEMA treatment. SEM view of a fractured specimen showed some cohesive failure in cured resin, but almost all of the fractured surface shows boundary failure between the penetrated resin and underlying dentine. A cross-sectional view of the interface showed a very thick hybrid layer between the hybridized dentine and underlying dentine. It was concluded that HEMA treatment following acid conditioning provided a slightly higher bond strength for both the Er:YAG laser-irradiated and non-irradiated dentines. However, the bond strength of Er:YAG laser irradiated dentine was significantly lower than that of the non-irradiated dentine.

Animals↗

PubMed2001

Resin bonding to Er: YAG laser-irradiated dentin: combined effects of pre-treatments with citric acid and glutaraldehyde.

The purpose of this study was to evaluate the combined effects of citric acid and glutaraldehyde (GA) on the resin bonding to Er: YAG laser-irradiated dentin. Bovine dentin was prepared with 180- to 600-grit SiC paper and then uniformly irradiated with an Er: YAG laser (laser-irradiated group) or immersed in water at 60 degrees C for 15 min (heated group). The samples were then acid-conditioned with 10% citric acid (10-0) or 10% citric acid/3% ferric chloride (10-3) for 15 s and treated with GA for 10 min before bonding to an acrylic rod with 4-META/MMA-TBB resin. These samples were trimmed to prepare miniaturized dumbbell-shaped specimens. After storage in water at 37C for 1 d, the tensile bond strength was measured, and the fractured surface was evaluated using a scanning electron microscope (SEM). In the laser-irradiated and heated groups, the 10-3+GA-treated specimen had higher bond strength than that of 10-0+GA. On the other hand, the tensile bond strength of 10-3 +GA in the non-irradiated group was lower that that of 10-0+GA. In conclusion, the combination of 10-3 and GA for bonding with 4-META/MMA-TBB resin was the most effective for Er: YAG laser-irradiated dentin and heated dentin, but it was not effective for the non-irradiated dentin.

Acid Etching, Dental↗

PubMed2001

Intestinal absorbability of wheat allergens, subunits of a wheat alpha-amylase inhibitor, expressed by bacteria.

Wheat CM2, CM3 and CM16 proteins are known as subunits of the tetrameric alpha-amylase inhibitor as well as major allergens to baker's asthma. The purpose of this study is to produce these CM proteins by bacteria in a quantity adequate for studying the penetration characteristics of the CM proteins through intestinal mucosa in rats and Caco-2 cells. cDNAs encoding the mature proteins were expressed in Escherichia coli and purified by an Ni2+-chelating column. The recombinant proteins were radioiodinated and admministered orally to rats or applied to the apical site of the Caco-2 cell monolayer. The radioactivity in the trichloroacetic acid-insoluble fraction, which was mainly composed of peptides with molecular mass less than that of the intact CM proteins, in the serum and the basolateral medium was highest in recombinant CM3. Accordingly, the intestinal absorption of these three proteins in the form present in wheat should be evaluated.

Allergens↗

PubMed2001

Application of sintered titanium alloys to metal denture bases: a study of titanium powder sheets for complete denture base.

The purpose of this study was the fabrication of titanium powder sheets to enable the application of sintered titanium alloys as metal denture bases. The effects of titanium particle shape and size, binder content, and plasticizer content on the surface smoothness, tensile strength and elongation of titanium powder sheets was investigated. To select a suitable ratio of powdered metal contents for application as a metal denture base, the effects of aluminum content in Ti sheets and various other powder metal contents in Ti-Al sheets on the density, sintering shrinkage, and bending strength were evaluated. Based on the results of the above experiments, we developed a mixed powder sheet composed of 83Ti-7Al-10Cr with TA45 titanium powder (atomized, -45 microm), and 8 mass% binder content. This titanium alloy sheet had good formability and ductility. Its sintered titanium alloy had a density of 3.2 g/cm3, sintering shrinkage of 3.8%, and bending strength of 403 MPa. The titanium alloy sheet is clinically acceptable for fabricating denture bases.

Aluminum↗

PubMed2001

Casting accuracy of experimental Ti-Cu alloys.

The purpose of the present study was to investigate the casting accuracy and the dimensional change of experimental titanium-copper alloys (3.0 and 5.0 mass% Cu; hereafter, only "%" will be used) and to compare the findings with those of pure titanium. Castings were made using an argon-arc melting/pressure difference-casting unit. The fit of the metals cast in both full crown and MOD inlay dies was evaluated by measuring the distance between the shoulder margin and the cervical shoulder of the die. The changes in the inner diameter of castings were determined. In addition, surface roughness measurements inside the castings were carried out using a conventional profilometer, and thermal expansion measurements were made on cast cylindrical specimens using a differential dilatometer. There were no significant differences in dimensional change between pure titanium and the titanium-copper alloys. The fit of the titanium-copper alloys was inferior to pure titanium. The results of surface roughness measurements showed significance differences between the roughness of the pure titanium and titanium-copper alloys.

Analysis of Variance↗

PubMed2001

Removal and decomposition of malodorants by using titanium dioxide photocatalyst supported on fiber activated carbon.

Effective and compact deodorization systems have been required for the measure of small-scale emission sources of offensive odors usually found in urban areas. We have developed a sheet material with titanium dioxide (TiO2) photocatalyst supported on fiber activated carbon (FAC) for a compact deodorization system. In the deodorization system using the TiO2/FAC sheet and a ultraviolet lamp, malodorants can be collected on the TiO2/FAC sheet by adsorption and then decomposed by photocatalysis with UV-irradiation. In this study, we obtained basic information about the removal and the decomposition of malodorants in the photocatalytic deodorization system using the TiO2/FAC sheet. The malodorants used in this study were methyl mercaptan, ammonia, and hydrogen sulfide. In addition, two kinds of light sources, a black light bulb (BLB; dominant wavelength: 365 nm) and an ultraviolet germicidal lamp (UV2; dominant wavelength: 254 nm) were used to analyze the effect on removal and decomposition characteristics by different dominant wavelengths. The removal rates of malodorants from the gas phase were determined in the deodorization system in the presence or absence of the TiO2/FAC sheet and UV-irradiation in order to study each removal effect due to adsorption onto the TiO2/FAC sheet, direct photolysis by UV-irradiation, and photocatalytic decomposition. The effect of adsorption onto the TiO2 /FAC sheet was pronounced in this batch-type experiment. The effect of photocatalysis was observed from the removal rates of methyl mercaptan. The percent oxidation of ammonia to nitrate and that of methyl mercaptan to sulfate were examined by determining products, i.e. nitrate and sulfate ions, with purified water after the reaction. The formation of nitrate or sulfate was not observed without UV-irradiation using the BLB, while the reactions progressed in the presence of the TiO2/FAC sheet. When the UV2 lamp was used, the oxidation of methyl mercaptan to sulfate occurred without the TiO2/FAC sheet. This suggests that the decomposition characteristics of malodorants were dependent on the wavelength of the light source.

Air Pollutants↗

PubMed2000

Influence of finishing on the electrochemical properties of dental alloys.

Dental alloy surface finishing procedures of may influence their electrochemical behavior, which is used to evaluate their corrosion resistance. We examined the polarization resistance and potentiodynamic polarization profile of the precious-metal alloys, Type 4 gold alloy and silver-palladium alloy, and the base-metal alloys, nickel-chromium alloy, cobalt-chromium alloy, and CP-titanium. Three types of finishing procedure were examined: mirror-finishing using 0.05 micron alumina particles, polishing using #600 abrasive paper and sandblasting. Dissolution of the alloy elements in 0.9% NaCl solution was also measured and compared with the electrochemical evaluation. The corrosion resistance of the dental alloys was found to relate to finishing as follows: The polarization resistance and potentiodynamic polarization behavior revealed that the corrosion resistance improved in the order of sandblasting, #600-abrasive-paper polishing, and mirror-finishing. While the corrosion potential, critical current density and passive current density varied depending on the type of finishing, the transpassive potential remained unchanged. The influence of finishing on the corrosion resistance of precious-metal alloys was less significant than on that of base-metal alloys. A mirror-finishing specimen was recommended for use in evaluation of the corrosion resistance of various dental alloys.

Alloys↗

PubMed2000

Influence of different acid conditioners on the tensile bond strength of 4-META/MMA-TBB resin to Er:YAG laser-irradiated bovine dentin.

PURPOSE: This study evaluated the effect of acid conditioners on resin bonding to dentin following irradiation with an Er:YAG laser and investigated the characteristics of resin bonding to the laser-treated dentin. MATERIALS AND METHODS: Extracted bovine teeth were cervically sectioned to expose a dentin surface. After polishing, the dentin was irradiated with an Er:YAG laser. Aqueous solutions of 10% citric acid (10-0) or 10% citric acid/3% ferric chloride (10-3) were then applied to the laser-treated surface as acid conditioners. After the acid treatment, a PMMA rod was bonded to the irradiated dentin using 4-META/MMA-TBB resin, and miniaturized dumbbell-shaped bonded specimens were prepared. These specimens were subjected to tensile testing, and fractured surfaces were observed with field-emission scanning electron microscopy (FE-SEM) to determine the mode of fracture. Additionally, the resin-dentin interfaces were observed under FE-SEM. RESULTS: The tensile bond strength of acid-conditioned bonded specimens was lower than that of specimens not subjected to acid treatment (11.1 MPa) in the laser-irradiated group. No significant difference was observed between 10-0 and 10-3 treatments. 10-3 treatment yielded the highest bond strength (24.6 MPa) in the nonirradiated group, as opposed to only 7.7 MPa in the laser-treated group. Cohesive failure in the dentin was observed in almost all specimens in the irradiated group. Furthermore, a 10- to 30-micron-thick resin-penetrated layer was observed at the interface between the dentin and resin. CONCLUSION: These results suggest that the effect of acid conditioners on resin bonding to dentin differs according to whether the dentin has been laser irradiated or not.

Acid Etching, Dental↗

PubMed1999

Primary nonsecretory plasma cell leukemia: a rare variant of multiple myeloma.

We report a patient with primary nonsecretory plasma cell leukemia. These cells resembled prolymphocytes and expressed only CD38 and CD56. Due to the atypical morphology and lack of monoclonal immunoglobulins in both serum and urine, it was difficult to make a correct diagnosis. Electron-microscopic and immunocytochemical cytoplasmic studies were useful.

Aged↗

PubMed1999

Microhardness evaluations of resin-dentin bonding areas by nano-indentation.

The purpose of this experiment was to determine the hardness values of the hybrid layer and its surroundings through the continuous use of a microhardness measuring device. Black's Class V cavities were prepared in nine dog teeth. The cavities were divided into four groups according to the dentin adhesive system applied. The adhesive systems were: "Bond One System", "Liner Bond II sigma System", "One Step System", and "Single Bond System". The treated teeth were observed at seven days post-application. Specimens were cross-sectioned perpendicularly or horizontally to the resin-dentin interface and embedded in epoxy resin. Their surfaces were polished. The microhardness of the resin-dentin bonding area was measured with a nano-indentation tester. The hardness values at a point of 10 microns distant from the interface in the direction of the dentin differed between systems. It appeared that this was influenced by the presence of the decalcified dentin not impregnated by resin, differences in the chemistry forming the hybrid layer, and the composition of the bonding resin. The hardness of the dentin-bonding interface and its surroundings was determined, and these areas were observed using SEM. Three layers were confirmed the healthy dentin layer, the composite resin layer, and the hybrid layer, (in which decalcified dentin impregnated by resin and that not impregnated by resin are considered to be mix). In the hybrid layer, no impression was found by SEM although the hardness in the bonding interface was significantly different. These layers appear to be more elastic and softer than the healthy dentin.

Animals↗

PubMed1999

[The role of protein kinases and phosphatases in erythroid colony formation of elderly].

Using H-7, HA1001, FK506, cyclosporin A (CsA) and okadaic acid (OA), which are protein kinase and phosphatase inhibitors, we examined qualitative changes in hematopoietic precursor cells due to aging from the viewpoint of the role of protein kinases and phosphatases. Though H-7 and OA suppressed erythroid colony formation both in the elderly (age: 72-92, median: 86) and the young (age: 22-39, median: 29), no change due to aging was noted. HA1001 did not affect erythroid colony formation either in the elderly or the young. Erythroid colony formation was enhanced by FK506 and CsA in the young, however, erythroid colony formation was suppressed in the elderly. Similar examinations using cell fractions of non-T, non-macrophage, non-T + T, and CD34 positive cells were performed in both groups. Enhancement of erythroid colony formation in the young and suppression in the elderly by FK506 using unseparated MNC disappeared after removal of T cells. Enhancement of colony formation in the young and suppression of colony formation in the elderly were recovered when T cells were added again. The effects of FK506 and CsA on erythroid colony formation were thought to be the results of T cell inactivation, and the different sensitivity to FK506 and CsA in the elderly and young seemed to be the result of changes in the control mechanisms of hematopoiesis, such as the regulation of cytokine production by T cells, caused by aging.

Adult↗

PubMed1998

The effects of retraction forces applied to the anterior segment of orthodontic arch wires: differences in wire deflection with wire size.

Orthodontic arch wire deflection was studied in relationship to retraction forces applied to arch wires during anterior retraction with sliding mechanics. Two different sizes of orthodontic stainless steel arch wires (SS wires) .016" x .022" and .019" x .025", were examined. Retraction forces were generated using an elastic polymer material to measure arch wire deflection and applied to the arch wires by a commonly-used anterior retraction device with power chains hooked from the first molar areas to the pre-welded posts at distal site of the lateral incisors. The force application caused both the .016" x .022" and the .019" x .025" arch wires to deflect. The amount of deflection increased almost in proportion to the retraction force applied. With the same retraction force applied, the amount of deflection of the .019" x .025" wire was approximately 47.1% of that of the .016" x .022" wire.

Dental Arch↗

PubMed1997

Possible involvement of protein kinase C in the aberrant regulation of erythropoiesis in polycythemia vera.

To examine the possible involvement of protein kinase C (PKC) in the regulation of aberrant erythropoiesis of polycythemia vera (PV), we investigated the effects of PKC inhibitors on in vitro burst-forming unit of erythroid (BFU-E)-derived colony formation by bone marrow (BM) and peripheral blood (PB) cells obtained from five PV patients. 1-(Isoquinoline-sulfonyl)-2-methylpiperazine dihydrochloride (H-7), an inhibitor of PKC, suppressed the colony formation by BM and PB cells of PV patients in a dose-dependent manner, similar to those in the normal individuals. However, the 50% inhibitory concentrations (IC50) of H-7 in PV BM and PB cells were significantly higher than those in normal BM and PB cells, respectively. The BFU-E-derived colony formation by PV BM and PB cells was also less affected by Staurosporine, another PKC inhibitor, than those in a normal subject. Furthermore, in the study of PV, the IC50 of endogenous colonies formed in the absence of erythropoietin was much higher than that of colonies formed by the stimulation of erythropoietin. By contrast, N-(2-guanidinoethyl)-5-isoquinolinesulfonamide dihydrochloride (HA1004), a cyclic AMP-dependent kinase inhibitor, did not have such inhibitory effects. These findings suggest that PKC, as a second messenger, is involved in the regulation of aberrant erythropoiesis of PV.

Adult↗

PubMed1997

Transient sick sinus syndrome associated with immunoblastic lymphadenopathy.

We describe a very rare case of immunoblastic lymphadenopathy (IBL) accompanied with a sick sinus syndrome (SSS) in a 64-year-old male. SSS presented with progression of the IBL and subsided with improvement of the IBL following high dose prednisolone (PSL) therapy. The clinical course of this patient strongly suggested cardiac involvement in IBL and being the cause of the transient SSS. To our knowledge, this is the first case of IBL demonstrating SSS as a possible complication of the disease. This case may provide further information for the treatment of similar patients with IBL.

Electrocardiography↗

PubMed1997

[A case of adult idiopathic thrombocytopenic purpura associated with atypical mumps virus infection].

A 30-year-old male admitted to out hospital complaing of petechiae. He had attack of fever 2 days before admission, without parotitis and orchitis. Laboratory data showed marked thrombocytopenia. Bone marrow showed normocellularity with an increase of megakaryocytes. Antimumps IgM was positive by the EIA. He was diagnosed as idiopathic thrombocytopenic purpura (ITP) associated with mumps virus infection. After the administration of oral prednisolone and 5 days-infusion of gamma-globulin, platelet count increased rapidly. Prednisolone discontinued within 35 days, as in acute ITP, and he maintained remission. In conclusion, the test for antiviral antibodies is indispensable to exclude acute ITP in adult ITP patients.

Adult↗