Influencia de los inhibidores de las metaloproteinasas, agentes reticuladores y remineralización biomimética en la longevidad de la unión adhesiva. Parte 1: Inhibidores de las metaloproteinasas / Mtelloproteinase inhibitors, cross-linking agents and biomimentic remineralization influence in the adhesive bond longevity. Part 1

La capa híbrida es lograda mediante la desmineralización superficial de la dentina a través de la aplicación de acondicionadores acídicos y su posterior infiltración con resinas adhesivas, para conseguir una estructura compuesta por fibras de colágeno tipo I y proteoglicanos envueltos por cadenas de polímeros (Toledano et al, 2012). La matriz de colágeno parcialmente desmineralizada constituye un andamio adecuado para la remineralización en presencia de materiales bioactivos (Osorio et al, 2012). Sin embargo, en la base de la capa híbrida yace una capa de volumen reducido de colágeno desprotegido -dada la inadecuada infiltración resinosa así como también la ausencia de minerales intrafibrilares- y desmineralizado -tanto por acción del ácido fosfórico como por acción del ácido etilen diamino tetra acético (EDTA) - que puede sufrir degradación hidrolítica (Toledano et al, 2012; 2014 b) por acción de metaloproteinasas endógenas de la matriz (MMP) (Hebling et al, 2005). Esta actividad degradativa enzimática reduce el éxito clínico de las restauraciones adheridas debido a la pérdida de integridad en la interfaz de adhesión (Toledano et al, 2014 a).La barrera crítica al progreso en la adhesión a dentina, esto es el agua entrampada en los compartimentos intrafibrilares de las fibras de colágeno, no puede ser eliminada luego que éste es impregnado con resinas polimerizadas....

The hybrid layer is accomplished by the application of acidic conditioners to achieve a demineralized dentin surface that is subsequently infiltrated with adhesive resins, to obtain a type I collagen and proteoglycans polymer enveloped structure (Toledano et al, 2012).The partially demineralized collagen matrix provides a suitable scaffold for remineralization in the presence of bioactive materials (Osorio et al, 2012). However, at the hybrid layer’s bottom lies a reduced volume of unprotected -given the inadequate resin infiltration and also the absence of intrafibrillar minerals- and demineralized collagen –by the effect of both phosphoric and ethylene diamine tetra acetic acids (EDTA) - that can undergo hydrolytic degradation (Toledano et al, 2012; 2014 b) due to the activity of endogenous matrix metalloprotei-nases (MMPs) (Hebling et al, 2005). This degradative enzymatic activity reduces the clinical success of bonded restorations because of the loss of integrity at the adhesion interface (Toledano et al, 2014 b).The critical barrier to progress in dentine bonding, that is the water trapped in intrafibrillar collagen fiber compartments, cannot be elimi-nated after dentine is impregnated with polymerized resins...

Efficient amplification of melanoma-specific CD8+ T cells using artificial antigen presenting complex

In vitro large amplification of tumor-specific cytotoxic T lymphocytes (CTLs) and adoptive transfer of these cells is one of the most promising approaches to treat malignant diseases in which an effective immune response is not achieved by active immunization. However, generating sufficient numbers of tumor-specific CTLs stimulated with autologous antigen presenting cells (APCs) in vitro is one of the most problematic steps in the adoptive cell transfer (ACT) therapy. To circumvent this problem, we have developed an artificial antigen presenting complex (aAPCs) using MHC class I molecules loaded with a melanoma-specific TRP-2 peptide epitope. Our results show that TRP-2-specific CD8+ T cells elicited by immunization with recombinant adenovirus expressing the mini-gene epitope are efficiently stimulated and amplified in vitro to a greater extent by aAPCs than by natural splenic APCs. These aAPC-induced CTLs recognized endogenously processed antigens present on B16F10 melanoma cells. Efficient stimulation and proliferation of antigen- specific T cells was also confirmed using ovalbumin peptide-loaded aAPCs and OT-I TCR transgenic cells. These results demonstrate that prior in vivo immunization, which increases the precursor frequency, simplifies posterior expansion of tumor- specific CD8+ T cells, and aAPCs is superior to autologous APC for in vitro amplification. This prime and expand regimen can be an alternative method for large amplification of rare tumor-specific CTLs and aAPCs should be a useful tool for ACT immunotherapy.