RESUMEN
This study investigates the temporal changes in development of technology convergence networks by institution type, i.e., public research institute (PRI), university and industry. Using the co-classification of technological domains of patents, we identified technology convergence of Korean patents, which were filed at Korea Intellectual Properties Office (KIPO) from 1997 to 2011. We conducted a network analysis at the technology level to search for the key technology fields and frequent instances of technology convergence. The results show that technology convergence networks have grown significantly in the recent period regardless of the institution type. While industries started to conspicuously engage in technology convergence in the late 1990s, universities or PRIs did not do so until the mid-2000s. This discrepancy in the phase of technology convergence is attributed to the temporal difference in R&D stage (e.g., basic research and commercial product development). Our findings imply that corporal and governmental R&D management decision on promising technology fields will be more effective if the decision makers carefully consider the type of R&D entity in analyzing technological landscapes.
Asunto(s)
Investigación , Tecnología , Patentes como Asunto , República de CoreaRESUMEN
P. gingivalis is a major pathogen that is involved in the onset and progression of periodontal disease. This study investigated the effect of resveratrol, a naturally occurring polyphenol, on P. gingivalis LPS-accelerated vascular inflammation, a key step in the progression of periodontitis. Resveratrol significantly inhibited the P. gingivalis LPS-induced adhesion of leukocytes to endothelial cells and to the aortic endothelium by down-regulating the cell adhesion molecules, ICAM-1 and VCAM-1. Moreover, the inhibition of the P. gingivalis LPS-induced cell adhesion molecules by resveratrol was mainly mediated by nuclear factor-kappaB (NF-kappaB). Resveratrol suppressed P. gingivalis LPS-stimulated IkappaBalpha phosphorylation and nuclear translocation of the p65 subunit of NF-kappaB in HMECs. Overall, these findings suggest that resveratrol significantly attenuates the P. gingivalis LPS-induced monocyte adhesion to the endothelium by suppressing the expression of the NF-kappaB-dependent cell adhesion molecules, suggesting its therapeutic role in periodontal pathogen-induced vascular inflammation.
Asunto(s)
Antiinflamatorios/farmacología , Células Endoteliales/efectos de los fármacos , Molécula 1 de Adhesión Intercelular/metabolismo , Lipopolisacáridos/farmacología , Porphyromonas gingivalis/patogenicidad , Estilbenos/farmacología , Factor de Transcripción ReIA/metabolismo , Molécula 1 de Adhesión Celular Vascular/metabolismo , Animales , Adhesión Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Células Endoteliales/inmunología , Humanos , Proteínas I-kappa B/metabolismo , Molécula 1 de Adhesión Intercelular/genética , Leucocitos/efectos de los fármacos , Leucocitos/inmunología , Lipopolisacáridos/aislamiento & purificación , Masculino , Inhibidor NF-kappaB alfa , Fosforilación , Porphyromonas gingivalis/química , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Resveratrol , Transcripción Genética/efectos de los fármacos , Células U937 , Molécula 1 de Adhesión Celular Vascular/genéticaRESUMEN
Porphyromonas gingivalis is a major periodontal pathogen. The lipopolysaccharide (LPS) secreted from P. gingivalis is implicated in the initiation and progression of periodontitis. Aberrant angiogenesis is often associated with lesion formation in chronic periodontitis. In this study, we report that P. gingivalis LPS activates angiogenic cascade, migration, invasion and tube formation in human umbilical vein endothelial cells (HUVECs). Furthermore, P. gingivalis LPS potently stimulated in vivo neovascularization in chick chorioallantoic membrane (CAM) and the mouse Matrigel plug assay. P. gingivalis LPS had no effect on the expression of vascular endothelial growth factor (VEGF) or its receptor, Flk-1, implying that P. gingivalis LPS-induced angiogenesis may result from its direct action on endothelial cells. P. gingivalis LPS evoked activation of the mitogen-activated protein kinase ERK1/2 in HUVECs, which is closely linked to angiogenesis. Taken together, these results strongly suggest P. gingivalis LPS plays an important role in the pathological angiogenesis for periodontal diseases, such as periodontitis.