ABSTRACT
Transforming growth factor beta (TGF-beta) has well-documented roles in chondrocyte maturation and endochondral ossification, but the mechanisms of TGF-beta activation during these processes remain unclear. In this study, we analyzed TGF-beta activation in chick embryo resting, proliferating, and hypertrophic chondrocytes in culture. We found that both levels and activation of TGF-beta increased substantially with maturation. The majority of TGF-beta produced by resting cells over culture time remained latent, but a larger portion produced by proliferating and hypertrophic cells was activated with increasing maturation. Zymography of gelatin gels revealed that matrix metalloprotease 2 (MMP-2) and MMP-9 were expressed by each population and that MMP-13 characterized hypertrophic chondrocytes and to a lesser extent proliferating chondrocytes in late cultures. Treatment with pharmacologic agents revealed that both MMPs and serine proteases are involved in activation. However, because inhibition of MMPs almost completely prevented TGF-beta activation, MMPs appear crucial for activation. During culture, inclusion of the tetracycline-derived, collagenase/gelatinase inhibitor chemically modified nonantimicrobial tetracycline (CMT-8) at concentrations specific for MMP-13 inhibition resulted in complete inhibition of TGF-beta activation by proliferating and hypertrophic chondrocytes. These results show that TGF-beta production, release, and activation are regulated developmentally in chondrocytes. Our findings point to a strict mode of regulation of this potent factor to elicit diverse and highly specific effects during chondrocyte maturation and ossification.
Subject(s)
Chondrocytes/metabolism , Collagenases/metabolism , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/metabolism , Transforming Growth Factor beta/metabolism , Animals , Cells, Cultured , Chick Embryo , Chondrocytes/cytology , Collagenases/genetics , Matrix Metalloproteinase 13 , Matrix Metalloproteinase Inhibitors , Osteogenesis , Protease Inhibitors/pharmacology , Tetracyclines/pharmacologyABSTRACT
Se presentan 3 pacientes con aneurismas de las arterias gastroduodenal y pancreaticoduodenal. Se hacen algunas consideraciones respecto a las modalidades tecnicas que el cirujano puede utilizar en el tratamiento de la afeccion
Subject(s)
Middle Aged , Aged , Humans , Male , Female , Aneurysm , Duodenum , Pancreas , Surgical Procedures, OperativeABSTRACT
Se analizan los resultados obtenidos en una serie de 132 intervenciones efectuadas sin "shunt" interno en la que solo fallecio 1 enfermo (hipertension arterial incontrolable). Tuvieron deficit neurologico transitorio 3 pacientes (2,2%) y definitivo 2 (1,5%). El tiempo de oclusion carotidea vario entre 3 y 9 en el 85% de las operaciones y entre 9 y 19 en el 15% restante. De acuerdo a estos resultados los autores consideran que la endarterectomia carotidea realizada con anestesia general, ligera hipertension arterial, en normocarbia, sin "shunt" intraarterial, permite sostener la opinion que el procedimiento es sencillo, pudiendo efectuar minuciosa correccion de la patologia presente, con indice de seguridad simulares o mejores que con otras tecnicas, incluindo el "shunt" interno, aun en pacientes en que este estaria teoricamente indicado
Subject(s)
Adult , Middle Aged , Aged , Humans , Male , Female , Carotid Artery Diseases , EndarterectomyABSTRACT
Se presentan y analizan 25 pacientes sometidos a 26 anastomosis mesentericocavas;en 6 casos se realizo la tecnica de Marlon Claworthy y en 19 la de Drapanas con interposicion de protesis en H. Se aboga por esta ultima tecnica en indicaciones electivas, entre las cuales los autores tienen 2 decesos en 17 casos. Se discuten los factores que permiten aseverar que la tecnica comentada satisface de similar manera que otras la derivacion portosistemica
