RESUMO
Tissue engineering has typically been such an approach that relies on isolation and culture of primary cells (seed cells), seeding these cells onto porous scaffolds, maintaining under static or flow condition (Bioreactor) for a period of time prior to implantation. However, experience of almost thirty years in this research field tells us that the typical tissue engineering approach relies on autologous cells, expensive and time consuming. Tissue engineering products do not function very well and are difficult to get FDA approval. In recent years biomaterial scientists created a new concept "Tissue Inducible Biomaterials". The concept is based on designing of microstructure of scaffolds, chemical modification and incorporation of bioactive molecule to scaffolds. Thus the scaffolds gain tissue induction activity, and will facilitate tissue regeneration and repair in vivo. The concepts of "In Vivo Tissue Engineering" and "Tissue Inducible Biomaterials" are been recognized by the Society, and are becoming the new approaches in tissue engineering: Based on the research of the related references within the past three years, the present paper summarized the strategy of tissue inducible biomaterials.
Assuntos
Animais , Humanos , Materiais Biocompatíveis , Química , Regeneração Tecidual Guiada , Engenharia Tecidual , Alicerces TeciduaisRESUMO
273 spine apparatus were observed under electron microscope. The results were as follows: 1.The flat-type sac of 5 types of the sac which constituted the spine apparatus covered the majority. Most of them were arranged parallelly and a few dispersively. The horseshoe or braid shaped arrangement was also seen in some cases. 2.The number of the sac varied from 3 to 6 in most of the cases, and a few over 10. Sometimes 2 or 3 spine apparatus can be seen within a single dendritic spine. 3.The spine apparatus often locates in the dendritic spine. In some cases the spine apparatus can be seen within the dendrites or in the juncture of dendritic trunk and dendritic spine 4.The morphological structure of the dense bands is comparatively complex. Most of the bends are narrow, some are broad, fine granular or mist-like in shape. The dense bends are located in between the adjacent sacs mostly and in few cases on one side of the spine apparatus. In some cases, one end of the dense band is fused with the sac.
RESUMO
Objective To research the effect of exogenous estradiol(E-2) on transcriptional activity of regenerating hepatocytes in rats. Methods The E-2 levels in serum were measured using RIA and the numbers of argyrophil nucleolar organizer regions(AgNORs) were investigated. Results Rat serum E-2 level gradually declined after ovariectomy,and no E-2 could be measured after the 15th day.Exogenous E-2 could promote transcriptional activity of regenerating rat hepatocytes,particularly during the first 24h after PH,there was a dose-dependent increase in numbers of AgNORs 24-36h after PH,the exogenous E-2 cause a dose-dependent decrease in numbers of AgNORs,but all of the values were higher than that of control group.Conclusion E-2 can regulate the transcriptional activity of regenerating hepatocytes in rats.