Relationship between sintering temperature and transformation of phase for Y2O3 partially stabilized zirconia

The objective of this study was to verify the stability of Y2O3 partially stabilized zirconia (zirconia) sintered at 1,350℃ and 1,450℃ in a simulated oral environment over a long period of time. After sintering, zirconia was immersed in physiological saline, 1% lactic acid solution, and 1% malic acid solution which can be produced in the oral cavity for 3 or 6 months. The amount of yttrium released, and transformation from the tetragonal phase to monoclinic phase by X–ray diffraction were evaluated. Using X–ray diffraction, the monoclinic phase hardly existed for zirconia sintered at 1,350℃; however, for zirconia sintered at 1,450℃, the monoclinic phase existed. The amount of yttrium released was small after exposure to both 1% lactic acid solution and 1% malic acid solution for zirconia sintered at 1,350℃. In contrast, it showed a maximum relase after exposure for 6 months form zirconia sintered at 1,450℃. Based on the X–ray diffraction, the monoclinic phase did not increase for zirconia sintered at 1,350℃ after exposure to 1% lactic acid solution and 1% malic acid solution for 3 and 6 months. However, there was marked transformation for zirconia sintered at 1,450℃ after exposure for 6 months. The frequency of the monoclinic crystal structures increased with the release of yttrium, as confirmed by the results of X–ray diffraction and measurement. As a result of structural observation, the crystal grain size of zirconia sintered at 1,350℃ was finer than that sintered at 1,450℃. It was clarified that zirconia sintered at 1,350℃ was more suitable than that sintered at 1,450℃ as an implant material

冠動脈内圧測定により得られる病変重症度の新しい生理学的指標Epicardial Resistance Indexの基礎理論

冠動脈狭窄性病変の機能的重症度を評価するため,我利よ独自に,病変に特異的な新たな指標であるepicardial resistance index(ERI)を考案した.本論文ではERIの概念および理論的基礎を論説する.ERIは,薬物による最大充血状態(hyperemia)下において,心外膜に存在する冠動脈の狭窄性病変の血管抵抗と狭窄以下の末梢心筋部の抵抗の比で表される指標である.ERIは先端に圧センサーチップを有する圧測定ワイヤーを用いて,狭窄病変前後の冠動脈内圧を測定することで得られる病変部の圧較差を,末梢部血管内圧-中心静脈圧(末梢部心筋での圧較差)で除することにより計算される.測定を最大充血状態で行うのは,冠動脈内圧の自己調整機構の影響を排除するためである.冠動脈内圧の測定による狭窄病変の評価としては,従来fractional flow reserve(FFR)が指標として用いられていたが,同一冠動脈内に複数の病変を有する場合,個々の病変の重症度を個別に評価することは不可能であった.今回我々が考案した新たな指標であるERIは,個々の病変の抵抗を表す指標であるため,病変特異的に重症度評価を行うことが可能となった.単一病変において,虚血が生じえる病変の重症度の閾値は,FFRではcut-off値0.33であることを証明した.さらにFFRと異なり,同一血管に複数の病変がある場合もこのERI値が個々に計算可能で,重症度評価の指標となることを明らかにした.実臨床90病変において,PCI前後で病変のERI測定および定量的冠動脈造影を比較した結果,ERIと血管造影上の狭窄度はr=0.67と良好な正相関を示した.我々の考案したERIは,実際の臨床上問題となる複数の病変を有する複雑病変の治療に際し,どの病変を治療すれば虚血を解除することが可能か事前に判別することができ,不要な治療を避け,必要な病変のみ選択治療を施行できるという点で,特にカテーテルによる冠動脈治療上大きな意義があると考えられる.To assess functional severity of the coronary stenotic lesion, we introduce a novel lesion-specific parameter, the epicardial resistance index (ERI), and describe its concept and theoretical basis. The ERI is defined as the ratio of the resistance of an epicardial coronary stenosis to that of downstream myocardium under hyperemic condition. The ERI is calculated as the trans-lesional pressure gradient divided by (Pd-Pv) at maximum hyperemia, where Pd represents the mean distal coronary pressure in the absence of any stenosis and Pv represents the central venous pressure. Based on theoretical conversion of fractional flow reserve (FFR) to ERI, the reported FFR cut-off value of 0.75 for inducible ischemia corresponds to an ERI of 0.33. This new parameter allows the resistance of the each coronary stenosis to be assessed separately even in the presence of multiple lesions in a coronary artery tree. Using the 170 measurements performed in the 90 lesions, the correlation of ERI with the anatomical parameters obtained from QCA was analyzed. By polynomial regression analysis, the ERI showed a significant positive correlation with the QCA-derived %DS (r=0.67, p<0.001). ERI may have wide application in routine clinical practice especially in the setting of complex catheter-based coronary intervention

冠動脈内圧測定により得られる病変重症度の新しい生理学的指標Epicardial Resistance Indexの基礎理論

冠動脈狭窄性病変の機能的重症度を評価するため,我利よ独自に,病変に特異的な新たな指標であるepicardial resistance index(ERI)を考案した.本論文ではERIの概念および理論的基礎を論説する.ERIは,薬物による最大充血状態(hyperemia)下において,心外膜に存在する冠動脈の狭窄性病変の血管抵抗と狭窄以下の末梢心筋部の抵抗の比で表される指標である.ERIは先端に圧センサーチップを有する圧測定ワイヤーを用いて,狭窄病変前後の冠動脈内圧を測定することで得られる病変部の圧較差を,末梢部血管内圧-中心静脈圧(末梢部心筋での圧較差)で除することにより計算される.測定を最大充血状態で行うのは,冠動脈内圧の自己調整機構の影響を排除するためである.冠動脈内圧の測定による狭窄病変の評価としては,従来fractional flow reserve(FFR)が指標として用いられていたが,同一冠動脈内に複数の病変を有する場合,個々の病変の重症度を個別に評価することは不可能であった.今回我々が考案した新たな指標であるERIは,個々の病変の抵抗を表す指標であるため,病変特異的に重症度評価を行うことが可能となった.単一病変において,虚血が生じえる病変の重症度の閾値は,FFRではcut-off値<0.75と報告されている.我々は,数学的変換によりこの虚血閾値がERIでは,ERI値>0.33であることを証明した.さらにFFRと異なり,同一血管に複数の病変がある場合もこのERI値が個々に計算可能で,重症度評価の指標となることを明らかにした.実臨床90病変において,PCI前後で病変のERI測定および定量的冠動脈造影を比較した結果,ERIと血管造影上の狭窄度はr=0.67と良好な正相関を示した.我々の考案したERIは,実際の臨床上問題となる複数の病変を有する複雑病変の治療に際し,どの病変を治療すれば虚血を解除することが可能か事前に判別することができ,不要な治療を避け,必要な病変のみ選択治療を施行できるという点で,特にカテーテルによる冠動脈治療上大きな意義があると考えられる.To assess functional severity of the coronary stenotic lesion, we introduce a novel lesion-specific parameter, the epicardial resistance index (ERI), and describe its concept and theoretical basis. The ERI is defined as the ratio of the resistance of an epicardial coronary stenosis to that of downstream myocardium under hyperemic condition. The ERI is calculated as the trans-lesional pressure gradient divided by (Pd-Pv) at maximum hyperemia, where Pd represents the mean distal coronary pressure in the absence of any stenosis and Pv represents the central venous pressure. Based on theoretical conversion of fractional flow reserve (FFR) to ERI, the reported FFR cut-off value of 0.75 for inducible ischemia corresponds to an ERI of 0.33. This new parameter allows the resistance of the each coronary stenosis to be assessed separately even in the presence of multiple lesions in a coronary artery tree. Using the 170 measurements performed in the 90 lesions, the correlation of ERI with the anatomical parameters obtained from QCA was analyzed. By polynomial regression analysis, the ERI showed a significant positive correlation with the QCA-derived %DS (r=0.67, p<0.001). ERI may have wide application in routine clinical practice especially in the setting of complex catheter-based coronary intervention

Novel monoclonal antibody recognizing triglyceride-rich oxidized LDLs associated with severe liver disease and small oxidized LDLs in normal subjects

Background: Triglyceride-rich low-density lipoproteins (TG-rich LDLs) in the plasma of patients with severe liver disease are reported to change macrophages into foam cells in vitro. Methods: Male BALB/c mice were immunized with TG-rich LDLs isolated from the plasma of a patient with severe liver disease. The resulting monoclonal antibody (G11-6) was used in a sandwich enzyme-linked immunosorbent assay (ELISA) in combination with polyclonal anti-apolipoprotein B antibodies. The time course of copper-mediated LDL oxidation was monitored using this ELISA. The results were compared to those of the two commercial ELISAs for oxidized LDL using DLH or ML25, thiobarbituric acid reactive substances (TBARS), and the optical absorbance for the conjugated dienes generated in lipid peroxides. Further, the lipoprotein fractions separated by gel filtration were tested with this ELISA in healthy volunteers (n = 11) and patients (n = 3) with liver disease. Results: G11-6 reacted with oxidized LDLs during only the early phase of copper-oxidation, being distinct from the other monoclonal antibodies and methods. G11-6 was confirmed to react with TG-rich LDLs in patients, while it reacted with small LDL particles in normal controls. Conclusions: The monoclonal antibody G11-6 is useful for detecting oxidized small LDLs in normal controls and oxidized TG-rich LDLs in patients with severe liver disease