共查询到20条相似文献,搜索用时 31 毫秒
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Dependence of hepatocyte-specific gene expression on cell-cell interactions in primary culture. 总被引:13,自引:0,他引:13
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J M Fraslin B Kneip S Vaulont D Glaise A Munnich C Guguen-Guillouzo 《The EMBO journal》1985,4(10):2487-2491
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Persistence of liver-specific messenger RNA in cultured hepatocytes: different regulatory events for different genes 总被引:14,自引:1,他引:13
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《The Journal of cell biology》1987,105(6):2877-2885
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Hormonal regulation of myosin heavy chain and alpha-actin gene expression in cultured fetal rat heart myocytes 总被引:8,自引:0,他引:8
T A Gustafson J J Bahl B E Markham W R Roeske E Morkin 《The Journal of biological chemistry》1987,262(27):13316-13322
Thyroid hormone regulates the expression of ventricular myosin isoenzymes by causing an accumulation of alpha-myosin heavy chain (MHC) mRNA and inhibiting expression of beta-MHC mRNA. However, the mechanism of thyroid hormone action has been difficult to examine in vivo because of its diverse actions. Accordingly, hormonal control of expression of six MHC isoform mRNAs and cardiac and skeletal alpha-actin mRNAs was studied in primary cultures of fetal rat heart myocytes grown in defined medium. The results indicate that in the absence of thyroid hormone, cultured heart cells express predominantly beta-MHC and cardiac alpha-actin mRNAs. Addition of 3,5,3'-triiodo-L-thyronine (T3) caused a rapid induction of alpha-MHC mRNA and decreased beta-MHC mRNA levels without affecting the skeletal muscle MHC mRNAs. There was an almost parallel change in the myosin isoenzymes. Cardiac alpha-actin mRNA levels were transiently increased by T3 treatment, but skeletal alpha-actin was unaffected. Elimination of insulin and epithelial growth factor from the medium did not alter the effects of T3 on cardiac MHC mRNA expression. Addition of various adrenergic agents to the medium had no appreciable effect on cardiac MHC mRNA expression despite the presence of functionally coupled alpha- and beta-adrenergic receptors. Addition of steroid hormones, muscarinic agents, and glucagon to the medium also had no effect. Thus, under defined conditions, T3 is able to regulate MHC gene expression at a pretranslational level without the need for other exogenous factors. 相似文献
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Modulation of beta-adrenergic response in rat brain astrocytes by serum and hormones 总被引:1,自引:0,他引:1
Purified astrocyte cultures from neonatal rat cerebrum respond to isoproterenol, a beta-adrenergic agonist, with a transient rise in cAMP production. This astroglial property was regulated by serum, a chemically defined medium (serum-free medium plus hydrocortisone, putrescine, prostaglandin F2 alpha, insulin, and fibroblast growth factor) and epidermal growth factor. Compared to astrocytes grown in serum-supplemented medium, astrocytes grown in the chemically defined medium were nonresponsive to isoproterenol stimulation, and this difference did not appear to be due to selection of a subpopulation of cells by either medium. The data suggest that a decreased beta-adrenergic receptor number and an increased degradation of cAMP may account for the reduced response to beta-adrenergic stimulation. The nonresponsive state of astrocytes in the defined medium was reversible when the medium was replaced with serum-supplemented medium. An active substance(s) in serum was responsible for restoring the responsiveness of astrocytes. Each of the five components of the defined medium had little effect by itself; however, together they acted synergistically to desensitize astrocytes to beta-adrenergic stimulation. On the other hand, epidermal growth factor, a potent mitogen for astrocytes, was very competent by itself in reducing the cAMP response of astrocytes to beta-adrenergic stimulation. Thus purified astrocytes grown in the chemically defined medium appear to be a good model for the study of hormonal interactions and of serum factors which may modulate the beta-adrenergic response. 相似文献
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Regulation of levels of specific Sertoli cell mRNAs by vitamin A 总被引:4,自引:0,他引:4
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P Galéra D Vivien S Pronost J Bonaventure F Rédini G Loyau J P Pujol 《Journal of cellular physiology》1992,153(3):596-606
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David G. Chilton Betty H. Johnson Laurence Danel-Moore Simon Kawa E. Brad Thompson 《In vitro cellular & developmental biology. Plant》1990,26(6):561-570
Summary CEM-C7, a human leukemic CD4+ T-lymphocyte cell line and three of its subclones, CEM-4R4, CEM-3R43, and ICR-27, previously
cultured in a medium supplemented with 5 to 10% fetal bovine serum, have been adapted to serum-free media. The best medium
of those tested was RPMI 1640 supplemented with 5 μg/ml each transferrin and insulin + 5 ng/ml sodium selinite ± 0.1% bovine
serum albumin. While growing either with or without albumin, the several clonal lines of CEM cells displayed growth similar
to serum-supplemented cultures. Cell proliferation of CEM-C7 cells cultured in both serum-free media has been sustained for
3 mo, with culture doubling times of about 25 h for both serum-supplemented and serum-free cultures (viability ≥ 90%). Cell
morphology remained essentially the same in serum-free or serum containing media. The expression of CD4, a marker for T-derived
lymphoid cells, was not significantly different in serum-free medium. When grown in serum-free medium, CEM-C7 cells exhibited
increased steroid responsiveness as evidenced by increased glucocorticoid receptor binding sites, increased induction of glutamine
synthetase, and cell lysis at lower concentrations of steroid. Receptor mutant subclones of CEM-C7, which are proven to be
completely unresponsive to micromolar concentrations of dexamethasone when grown in serum-supplemented medium, become partially
sensitive to the hormone after growth in defined medium. The increased sensitivity of CEM-C7 cells and its subclones to dexamethasone
in serum-free medium returned to previous levels when these cells were recultured in serum-containing medium. Our results
suggest that substances in serum influence steroid effects on these cells and that the molecular details of glucocorticoid
hormone action may be pursued more precisely in a clearly defined culture medium.
This work was conducted in conjunction with the Walls Medical Research Foundation. 相似文献
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Mechanical and biochemical characterization of cartilage explants in serum-free culture 总被引:10,自引:0,他引:10
Bian L Lima EG Angione SL Ng KW Williams DY Xu D Stoker AM Cook JL Ateshian GA Hung CT 《Journal of biomechanics》2008,41(6):1153-1159
Allografts of articular cartilage are both used clinically for tissue-transplantation procedures and experimentally as model systems to study the physiological behavior of chondrocytes in their native extracellular matrix. Long-term maintenance of allograft tissue is challenging. Chemical mediators in poorly defined culture media can stimulate cells to quickly degrade their surrounding extracellular matrix. This is particularly true of juvenile cartilage which is generally more responsive to chemical stimuli than mature tissue. By carefully modulating the culture media, however, it may be possible to preserve allograft tissue over the long-term while maintaining its original mechanical and biochemical properties. In this study juvenile bovine cartilage explants (both chondral and osteochondral) were cultured in both chemically defined medium and serum-supplemented medium for up to 6 weeks. The mechanical properties and biochemical content of explants cultured in chemically defined medium were enhanced after 2 weeks in culture and thereafter remained stable with no loss of cell viability. In contrast, the mechanical properties of explants in serum-supplemented medium were degraded by ( approximately 70%) along with a concurrent loss of biochemical content (30-40% GAG). These results suggest that long-term maintenance of allografts can be extended significantly by the use of a chemically defined medium. 相似文献
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