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Regenerative medicine is a burgeoning field that is important to combat challenging diseases and functional impairments. Compared with traditional cell therapies with evident shortcomings (e.g., cell suspension injection or tissue engineering with scaffolds), scaffold-free cell sheet technology enables transplanted cells to be grafted and fully maintain their viability on target sites. Clinical and experimental studies have advanced the application of cell sheet technology to numerous tissues and organs (e.g., liver, cornea and bone). However, previous reviews have failed to discuss vital aspects of this rapidly developing technology, and many new challenges are gradually emerging. This review aims to provide a comprehensive introduction to cell sheet technology from cell selection to the ultimate applications of cell sheets, and challenges and future visions are also described. 相似文献
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C O'Neill 《Journal of reproduction and fertility》1985,75(2):375-380
The platelet-activating factor (PAF) produced by mouse embryos showed similar kinetics of action and dose-response curve, in a bioassay, as did 1-0-alkyl-2-acetyl-sn-glyceryl-3-phosphocholine (PAF-acether). The activity of the embryo-derived PAF was not affected by inhibitors of the ADP (pyruvate kinase with phosphoenol pyruvate) or cyclo-oxygenase (indomethacin) pathways of platelet activation. Chlorpromazine, an inhibitor of the PAF-acether pathway of platelet activation, caused a significant inhibition of the effects of embryo-derived PAF. Phospholipases A2, C and D significantly inhibited the activity while lipase had no effect, suggesting a phospholipid structure. All the embryo-derived PAF was found in the chloroform fraction after chloroform:methanol (2:1 v/v) extraction, as was PAF-acether. Both factors migrated at a similar rate (Rf 0.10-0.12) on silica thin-layer chromatography (chloroform:methanol:water; 65:35:4 by vol.). The embryo-derived PAF therefore displays chemical, biochemical and physiological properties similar to those of PAF-acether. 相似文献
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Matthew J O'Neill 《BMJ (Clinical research ed.)》1980,281(6244):869-870
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The abundance of an mRNA encoding an HMG1/2 protein from Pharbitis nil (HMG1) has been previously shown to be regulated by light and an endogenous rhythm in cotyledons. A second Pharbitis nil HMG cDNA (HMG2) was characterized. The sequence of HMG2 was 82% and 86% identical to HMG1 at the nucleotide and amino acid level, respectively. As with HMG1, HMG2 mRNA was detected in all vegetative tissues and was most abundant in roots. However, unlike HMG1, HMG2 mRNA abundance did not increase upon transfer of cotyledons to darkness and did not exhibit regulation by an endogenous circadian rhythm when maintained in continuous darkness over a 68 h period. Similarly, while the abundance of HMG1 mRNA during a dark period that induced photoperiodically controlled flowering was dramatically affected by brief light exposure (night break), this treatment had no effect on HMG2 mRNA abundance. Collectively, these data are consistent with a role of HMG1 in contributing to the circadian-regulated and/or dark-regulated gene expression with constitutive expression of HMG2 playing a housekeeping role in the general regulation of gene expression in Pharbitis nil cotyledons. 相似文献