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排序方式: 共有105条查询结果,搜索用时 15 毫秒
41.
When mesenchymal precursor cells from bone marrow are cultured in the presence of dexamethasone, the existence of distinct non-adherent and adherent populations can be demonstrated. The addition of PGE2, forskolin, or dibutyryl-cAMP can induce a transition from the former to the latter and this may be an important mechanism in the bone anabolic effects of PGE2. On the other hand, phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C, and sulprostone, an agonist for the PGE2 receptor EP1/EP3 subtypes, had no effect. The phosphodiesterase inhibitor, isobutylmethylxanthine (IBMX), had a synergistic effect in combination with PGE2, whereas neomycin, an inhibitor of inositol phosphate activity, had no effect, and LiCl, an inhibitor of inositol triphosphate metabolism, had an inhibitory effect on the PGE2-induced transition. Consistent with this, the addition of PGE2 to non-adherent bone marrow cells caused a 100% increase in cAMP synthesis. These results suggest that the induction of the transition from non-adherent to adherent osteoblast precursor is mediated by the EP2-PGE2 receptor subtype via an increase in intracellular cAMP synthesis. 相似文献
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Charles P. Scutt Phillip J. Gates John A. Gatehouse Donald Boulter Ronald R. D. Croy 《Molecular & general genetics : MGG》1990,220(3):409-413
Summary A cDNA sequence homologous to the Brassica self-incompatibility locus specific glycoprotein (SLSG) sequence was isolated from stigmas of B. oleracea plants homozygous for the S5 allele. The nucleotide sequence of this cDNA was obtained and compared with the S6 allelic form of the SLSG. Evidence is presented which indicates that this sequence does not specify the self-incompatibility response of pollen.Abbreviations SDS
sodium dodecyl sulphate
- PVP
polyvinylpyrrolidone
- BSA
bovine serum albumin
- SLSG
self-incompatibility locus specific glycoprotein 相似文献
43.
We have studied the effect of leukotrienes, (LT): B4, C4, D4 and E4 and the hydroxyeicosatetraenoic acids (HETEs) 5-HETE and 12-HETE on bone resorption in vitro. Resorption was measured by colorimetric assay of calcium released from neonatal mouse calvaria maintained in organ culture for 72h. All the LTs and HETEs stimulated bone resorption, with optimum responses at picomolar or nanomolar concentrations. The responses were biphasic, with a decreasing effect at higher concentrations. In contrast, prostaglandin E2 (PGE2) stimulated resorption only at 10nM and above. Indomethacin partially inhibited resorption by LTB4, LTC4 and LTD4, but did not affect resorption stimulated by LTE4, 5-HETE and 12-HETE. These results indicate that lipoxygenase products of arachidonic acid are highly potent bone resorbing factors and may play an important role in the localised bone loss associated with inflammatory lesions. 相似文献
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Lucas A Smolders Bj?rn P Meij David Onis Frank M Riemers Niklas Bergknut Richard Wubbolts Guy CM Grinwis Martin Houweling Marian JA Groot Koerkamp Dik van Leenen Frank CP Holstege Herman AW Hazewinkel Laura B Creemers Louis C Penning Marianna A Tryfonidou 《Arthritis research & therapy》2013,15(1):R23
Introduction
Early degeneration of the intervertebral disc (IVD) involves a change in cellular differentiation from notochordal cells (NCs) in the nucleus pulposus (NP) to chondrocyte-like cells (CLCs). The purpose of this study was to investigate the gene expression profiles involved in this process using NP tissue from non-chondrodystrophic and chondrodystrophic dogs, a species with naturally occurring IVD degeneration.Methods
Dual channel DNA microarrays were used to compare 1) healthy NP tissue containing only NCs (NC-rich), 2) NP tissue with a mixed population of NCs and CLCs (Mixed), and 3) NP tissue containing solely CLCs (CLC-rich) in both non-chondrodystrophic and chondrodystrophic dogs. Based on previous reports and the findings of the microarray analyses, canonical Wnt signaling was further evaluated using qPCR of relevant Wnt target genes. We hypothesized that caveolin-1, a regulator of Wnt signaling that showed significant changes in gene expression in the microarray analyses, played a significant role in early IVD degeneration. Caveolin-1 expression was investigated in IVD tissue sections and in cultured NCs. To investigate the significance of Caveolin-1 in IVD health and degeneration, the NP of 3-month-old Caveolin-1 knock-out mice was histopathologically evaluated and compared with the NP of wild-type mice of the same age.Results
Early IVD degeneration involved significant changes in numerous pathways, including Wnt/β-catenin signaling. With regard to Wnt/β-catenin signaling, axin2 gene expression was significantly higher in chondrodystrophic dogs compared with non-chondrodystrophic dogs. IVD degeneration involved significant down-regulation of axin2 gene expression. IVD degeneration involved significant down-regulation in Caveolin-1 gene and protein expression. NCs showed abundant caveolin-1 expression in vivo and in vitro, whereas CLCs did not. The NP of wild-type mice was rich in viable NCs, whereas the NP of Caveolin-1 knock-out mice contained chondroid-like matrix with mainly apoptotic, small, rounded cells.Conclusions
Early IVD degeneration involves down-regulation of canonical Wnt signaling and Caveolin-1 expression, which appears to be essential to the physiology and preservation of NCs. Therefore, Caveolin-1 may be regarded an exciting target for developing strategies for IVD regeneration. 相似文献48.
Vialette-Guiraud AC Alaux M Legeai F Finet C Chambrier P Brown SC Chauvet A Magdalena C Rudall PJ Scutt CP 《Annals of botany》2011,108(4):589-598
BACKGROUND: The angiosperms, or flowering plants, diversified in the Cretaceous to dominate almost all terrestrial environments. Molecular phylogenetic studies indicate that the orders Amborellales, Nymphaeales and Austrobaileyales, collectively termed the ANA grade, diverged as separate lineages from a remaining angiosperm clade at a very early stage in flowering plant evolution. By comparing these early diverging lineages, it is possible to infer the possible morphology and ecology of the last common ancestor of the extant angiosperms, and this analysis can now be extended to try to deduce the developmental mechanisms that were present in early flowering plants. However, not all species in the ANA grade form convenient molecular-genetic models. SCOPE: The present study reviews the genus Cabomba (Nymphaeales), which shows a range of features that make it potentially useful as a genetic model. We focus on characters that have probably been conserved since the last common ancestor of the extant flowering plants. To facilitate the use of Cabomba as a molecular model, we describe methods for its cultivation to flowering in the laboratory, a novel Cabomba flower expressed sequence tag database, a well-adapted in situ hybridization protocol and a measurement of the nuclear genome size of C. caroliniana. We discuss the features required for species to become tractable models, and discuss the relative merits of Cabomba and other ANA-grade angiosperms in molecular-genetic studies aimed at understanding the origin of the flowering plants. 相似文献
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The clinical potential of mesenchymal stem cells (MSC) in tissue engineering and regenerative medicine is due to their self-renewal, proliferation and multi-lineage differentiation potential. Clinical use requires large cell numbers; which can, theoretically, be generated by ex vivo expansion of plastic adherent, MSC subpopulation, of bone marrow cells (BMC). Effects of serial culture on MSC phenotype were investigated using non-gel based quantitative proteomic methodology for static monolayer cultures of rat BMC. In total, 382 proteins were relatively quantified (≥ 2 peptides). Nine proteins were up-regulated and seven down-regulated at passage 4 relative to passage 2 (p ≤ 0.05). We propose that serial culture impacts on MSC expansion (observed decline in colony forming potential and colony size) is through a combination of osteogenic differentiation and ageing/senescence and propose six novel protein biomarkers as candidates for quality control purposes in bioprocessing. 相似文献