Comparative study of the microtensile bond strength of three different total etch adhesives with different solvents to wet and dry dentin: in vitro test

El objetivo de esta investigación fue comparar la resistencia adhesiva en micro-tensión del sistema adhesivo de grabado total XP Bond (Caulk-Dentsply) vs. Excite (Ivoclar/Vivadent) y Prime & Bond NT (Caulk-Dentsply). Cuarenta y dos (42) terceros molares humanos fueron cortados exponiendo la superficie dentinaria. Se dividieron en 3 grupos de 14 dientes (G1 XP Bond, G2 Excite, G3 Prime & Bond NT) y a su vez en 2 grupos de 7 dientes para cada condición de dentina húmeda (GH) y/o seca, (GS). Se empleo la técnica de grabado total con la respectiva variación de humedad, siguiendo las instrucciones del fabricante se colocaron los adhesivos y la resinas compuestas restauradoras color A3 (Ceram Duo G1, G3 y Tetric Ceram G2). Los dientes fueron seccionados con una sierra ISOMET 1000 (Buehler Ltd.) hasta obtener barras de 1mm² x 10 mm, que fueron sometidas a tracción a una velocidad de 5 mm/min en la máquina de pruebas universales (Adamel Lhomargy DY 36). Los datos colectados fueron grabados y analizados utilizando un diseño experimental para el estudio dos factores de efectos fijos utilizando el software Statgraphics versión 5.1. La variable tipo de adhesivo obtuvo un valor p=0,000, para la variable condición del sustrato p=0,0012 y las interacciones entre ambos factores p=0,0457 lo que indica diferencias estadísticas significativas. Los valores de resistencia a la tracción obtenidos fueron G1h=55,0642 MPa Desviación Estándar (DE) 3,09768; G1s=39,115 MPa DE 2,86789; G2h=34,1607 MPa DE 2,86789; G2s=32,7373 MPa DE 2,77065; G3h=37,3407 MPa DE 2,86789; G3s=31,0593 MPa DE 2,77065. En las condiciones en que se realizó esta investigación, XP Bond presentó los mayores valores de resistencia adhesiva en ambas condiciones. La condición de sustrato húmedo aumenta los valores de resistencia adhesiva para los adhesivos evaluados; sin embargo el adhesivo Excite presenta una menor susceptibilidad a la variación de la humedad dentinal.

Factors influencing the content of residual tert-butyl alcohol in cyclodextrin complex prepared by lyophilization cosolvent system / 药学学报

In order to minimize the residual tert-butyl alcohol (TBA) level in cyclodextrin complex prepared by freeze drying TBA/water cosolvent system, the formulation and lyophilization procedure that may influence the residual TBA was studied. Residual TBA in freeze dried cyclodextrin complex was determined by gas chromatography. The significant formulation and processing factors that influence residual TBA were identified by adjusting the initial TBA concentration in cosolvent, selecting cyclodextrin type (beta-cyclodextrin or hydroxypropyl beta-cyclodextrin), changing sample volume in flasket, altering freezing mode (fast freezing or slow freezing) and modifying the duration of secondary drying. The results show that the amorphous cyclodextrin material (hydroxypropyl beta-cyclodextrin), initial low TBA concentration in cosolvent and fast freezing would lead to high TBA residue in cyclodextrin complex, annealing was effective in reducing the residual TBA. The duration of secondary drying had no distinct effect on residual TBA. It is concluded that in order to reduce residual TBA in cyclodextrin complex prepared by lyophilization monophase solution, the initial TBA concentration in cosolvent should be higher than the crystal formation concentration, the appropriate cyclodextrin type and freeze drying processing should be choosen.

Trp-Lys-Tyr-Met-Val-Met stimulates phagocytosis via phospho-lipase D-dependent signaling in mouse dendritic cells

Dendritic cells (DCs) play a key role in activating the immune response against invading pathogens as well as dying cells or tumors. Although the immune response can be initiated by the phagocytic activity by DCs, the molecular mechanism involved in this process has not been fully investigated. Trp-Lys-Tyr-Met-Val-Met-NH2 (WKYMVM) stimulates the activation of phospholipase D (PLD) via Ca2+ increase and protein kinase C activation in mouse DC cell line, DC2.4. WKYMVM stimulates the phagocytic activity, which is inhibited in the presence of N-butanol but not t-butanol in DC2.4 cells. Furthermore, the addition of phosphatidic acid, an enzymatic product of PLD activity, enhanced the phagocytic activity in DC2.4 cells. Since at least two of formyl peptide receptor (FPR) family (FPR1 and FPR2) are expressed in DC2.4 as well as in mouse bone marrow-derived dendritic cells, this study suggests that the activation of FPR family by WKYMVM stimulates the PLD activity resulting in phagocytic activity in DC2.4 cells.

Effect of Ethanol on the Regulation of Smooth Muscle Tone in Rat Aorta

BACKGROUND AND OBJECTIVES: The aim of this study was to determine the effect of ethanol on the regulation of vascular tone. MATERIAL AND METHODS: Using rat aorta ring, isometric contraction and 45Ca uptake were measured. Phorbol 12,13-dibutyrate (PDBu), phenylephrine, KCl were used for the regulation of smooth muscle tone. RESULTS: Ethanol induced transient contraction in rat aorta ring by dose-dependent manner. Ethanol suppressed the dose dependent contractile responses of vascular strip by phenylephrine, KCl and PDBu. Endothelium-dependent relaxation by acetylcholine was inhibited by ethanol. Ethanol depressed 45Ca uptake by high KCl but not by phenylephrine or PDBu in rat aorta. n-butanol selectively suppressed tonic contraction by high KCl, but t-butanol did not at the same concentration of butanol in rat aorta. PDBu-induced contraction was selectively suppressed by n-butanol but not by t-butanol. CONCLUSIONS: These findings suggest that the action of ethanol on phospholipase D is involved in the decreased response of rat aorta strip by vasoconstrictors.