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1.
Seishi Nagamori Kiyotaka Fujise Satoshi Hasumura Sadamu Homma Hajime Sujino Haruo Kameda Hitoshi Endou 《In vitro cellular & developmental biology. Plant》1982,18(12):1017-1022
Summary Reuber H-35 hepatoma cells were examined for their ability to synthesize protein in vitro, especially to produce alpha-fetoprotein
(AFP). The presence of AFP in the culture supernatant solution was determined immunologically by the micro-Ouchterlony method.
Charge heterogeneity of AFP was examined electrophoretically in continuous gradient polyacrylamide microgels. With regard
to the duration of culture, there was no remarkable change in the ratio of two peaks of AFP, and which came out as a major
combined peak and a similar peak by PAS staining on the condition of added SDS. These findings indicated that Reuber H-35
hepatoma cells had potential to produce two charge variants of AFP in vitro.
A part of this study was performed in the Division of Biofunction Research, Biomedical Research Laboratories, The Jikei University
School of Medicine, with support by Grant-in-Aid for Scientific Research for 1981 of the Ministry of Education, Science and
Culture of Japan. 相似文献
2.
Lawrence E. Shapiro Neil Wagner 《In vitro cellular & developmental biology. Plant》1988,24(4):299-303
Summary Serum-free tissue culture medium consisting of a 1∶1 mixture of Dulbecco's modified Eagle's medium (DMEM) and Ham's F12 medium
is herein shown to support growth of Reuber H-35 cells over several days in culture. Cells were initially plated in serum
containing DMEM medium for 3 h. After cell attachment, serum is removed and replaced with a serum-free 1∶1 mixture of these
two commercially available tissue culture media. The doubling time of cell growth in this unsupplemented serum-free medium
was 46 h in lightly plated cultures over the first 5 d. The presence of transferrin (5 μg/ml) and insulin (3.3 nM) results in a cell doubling time of 17 h, which equaled the growth rate in medium containing 10% fetal bovine serum. In the
absence of transferrin, growth rates in serum-free medium were correlated with the cell density of cultures. Conditioned medium
from dense, serum-free cultures has growth-stimulating activity in recipient lightly plated cultures. This simple, serum-free
culture medium will facilitate studies on the growth regulation of H-35 rat hepatoma cells.
This work was funded by a feasibility grant from the American Diabetes Association, as well as by the National Institutes
of Health grants CA 24604-09 and CA 16463-14. 相似文献
3.
A perfusion culture of hybridoma cells in serum-free medium recycling transferrin was carried out, which greatly reduced the
level of transferrin that was needed. The culture was maintained even without supplying transferrin for nine days. IgG concentration
reached 1.1 mg ml−1 in a month of recycling and its ratio to the total protein was 45.8%. The affinity of the antibody did not decrease and no
degradation was observed after long recycling period. The cell density under recycling condition was 2≈3 times higher than
that without recycling. It was indicated that there was autocrine growth promoting activity in the culture supernatant. 相似文献
4.
García-Pelayo MC García-Peregrín E Martínez-Cayuela M 《Journal of cellular biochemistry》2003,90(3):586-591
There is controversy about the effect of saturated and polyunsaturated fats on 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, the main regulatory enzyme of cholesterogenic pathway. Results from dietary studies are difficult to interpret because diets normally contain a mixture of fatty acids. Therefore, we have used Reuber H35 hepatoma cells whose phospholipids were enriched in different individual fatty acids and have studied their effects on the cellular reductase activity. Lauric, myristic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids were supplemented to the culture medium coupled to bovine serum albumin. The four fatty acids were incorporated into phospholipids from cells grown in media containing whole serum or lipoprotein-poor serum (LPPS). Reductase activity of cells cultivated in a medium with LPPS was three to four times higher than those cultivated in medium with whole serum. Saturated fatty acids increased reductase activity of cells grown in medium with whole serum, whereas n-3 polyunsaturated fatty acids (PUFA) decreased it. However, both saturated and polyunsaturated fatty acids increased reductase activity when serum lipoproteins were removed. In conclusion, this is one of the first reports demonstrating that saturated and n-3 PUFA only show differential effects on HMG-CoA reductase activity in the presence of lipoproteins. 相似文献
5.
The recovery of serum-free medium proteins from poly-sulfone hollow fiber bioreactors (HFBRs) was investigated. More than 99% of the initial transferrin was adsorbed to the hydrophobic hollow fibers within 2 h of HFBR operation. A methodology to minimize transferrin adsorption by pre-adsorption of bovine serum albumin (BSA) was developed. BSA adsorption on suspended cut fibers was virtually complete within 1 h. BSA-coated fibers adsorbed only 5% of the transferrin within 10 days, whereas uncoated cut fibers adsorbed more than 99% of the transferrin within 1 h. An improved HFBR startup procedure, using a BSA-coating step before inoculation, resulted in substantially higher transferrin recovery. Additional factors influenced extracapillary space (ECS) transferrin concentrations. Pronounced downstream polarization of transferrin was observed in the ECS. In addition, the 30-kDa nominal molecular weight cutoff ultrafiltration membranes rapidly leaked transferrin from the ECS to the lumen. (c) 1993 John Wiley & Sons, Inc. 相似文献
6.
Yoshinobu Nagao Katsuzo Nishikawa 《In vitro cellular & developmental biology. Plant》1989,25(10):873-880
Summary Primary Rhodamine fibrosarcoma (RdF) cells from rats were shown to grow in serum-free medium supplemented with basic fibroblast
growth factor (bFGF), albumin, and transferrin, all of which were purified from RdF tissue. Their growth rate with these supplements
was similar to that of cells in medium supplemented with calf serum. bFGF purified from RdF tissue (Rd-bFGF), which was previously
designated as DNA synthesis factor, stimulated the growth of primary RdF cells maximally at 30 ng/ml in the presence of the
other two proteins. Albumin and transferrin were separated from partially purified tumor growth stimulating activity which
was previously shown to stimulate growth of primary RdF cells in serum-free medium. The albumin (RdA) and transferrin (RdT)
found in the extract of RdF tissue were not due simply to contamination of the tissue with blood, but to their accumulations
in the tissue. The growth stimulatory activities of RdA and RdT on primary RdF cells in serum-free medium were maximal at
30 and 10 μg/ml, respectively. These results suggest that Rd-bFGF, RdA, and RdT, all of which accumulate in the tumor tissue,
are essential for growth of RdF cells in the tissue.
This work was supported by a grant-in-aid for cancer research from the Ministry of Education, Science and Culture of Japan. 相似文献
7.
Terry L. Riss' David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1989,25(2):136-142
Summary The effect of 17β-estradiol (E2) on growth of GH4C1 rat pituitary tumor cells was investigated under serum-free conditions and with medium containing charcoal-extracted serum.
Serum-free TRM-1 medium was a 1∶1 (vol/vol) mixture of F12-DME supplemented with 50 μg/ml gentamicin, 15 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, 10 μg/ml insulin, 10 μg/ml transferrin, 10 ng/ml selenous acid, 10 nM 3,5,3′-triiodothyronine (T3), 50 μM ethanolamine, and 500 μg/ml bovine serum albumin. The cells grew continuously in TRM-1 but were E2 responsive only when growth was retarded by reducing the T3 concentration to 10 pM (TRM-MOD). Addition of 1 to 10 nM E2 to TRM-MOD increased growth by 0.3 to 0.9 cell population doublings over controls in 9 d. By using medium supplemented with
charcoal-extracted sera, basal growth became 1 to 1.5 cell population doublings in 9 d. Addition of 0.1 pM E2 to medium containing charcoal-extracted serum caused a significant increase in cell number whereas pM-nM concentrations stimulated 200 to 570% increases over controls. The effect of steroid hormone was the same in phenol-red-containing
and indicator-free medium. The data presented confirm that the major requirements for demonstration of estrogenic effects
in culture were optimum concentrations of thyroid hormones and the presence of yet-to-be-characterized serum factors.
This work was supported by National Cancer Institute (Bethesda, MD) grants CA-26617 and CA-38024, American Cancer Society
grant BC-255, and grant 2225 from The Council for Tobacco Research, U.S.A., Inc. 相似文献
8.
Masami Ogasawara David A. Sirbasku 《In vitro cellular & developmental biology. Plant》1988,24(9):911-920
Summary Growth of the MCF-7, T47D, and ZR-75-1 human breast cancer cells was established in a serum-free defined medium (MOM-1) composed
of a 1∶1 (vol/vol) mixture of Ham's F12 medium and Dulbecco's modified Eagle's medium containing 15 mM HEPES (pH 7.2), 2 mM 1-glutamine, 20 μg/ml glutathione, 10 μg/ml insulin, 10 μg/ml transferrin (Tf), 10 ng/ml selenous acid, 0.3 nM triiodothyronine, 50 μg/ml ethanolamine, 20 ng/ml epidermal, growth factor, 2.0 nM 17β-estradiol, and 1.0 mg/ml bovine serum albumin (BSA). Proliferation in MOM-1 was 50 to 70% of the serum stimulated rate.
Deletion of components from MOM-1 gave a medium (Tf-BSA) containing only HEPES, 10 μg/ml Tf, and 200 μg/ml BSA, which sustained
MCF-7 and T47D cells in a slowly dividing and mitogen responsive state; ZR-75-1 cells required Tf plus 1.0 mg/ml BSA. In Tf-BSA,
insulin and insulin-like growth factor I(IGF-I) were mitogenic with ED50 values of 2 to 3 ng/ml and 30 to 150 pg/ml, respectively, with MCF-7 cells. The T47D cells were responsive to these factors
in Tf-BSA but required 10-fold higher concentrations for ED50. At saturating concentrations, insulin and IGF-I promoted 1.5 to 3.5 cell population doublings over controls in 8 d. At≤ng/ml
concentrations, epidermal growth factor, insulin-like growth factor II, and basic fibroblast growth factor were mitogenic
for human breast cancer cells in Tf-BSA. Mitogen activities in uterus and pituitary extracts were assayed readily in Tf-BSA.
This new method offers a convenient means of comparing the potencies of growth-promoting factors on human breast cancer cells
without interfering activities known to be present in serum.
This work was supported by grants CA-38024 and CA-26617, from the National Cancer Institute, Bethesda, MD, and by American
Cancer Society grant BC-255 and grant 2225 from the Council for Tobacco Research, USA, Inc. 相似文献
9.
Michael H. Simonian Mark L. White David A. Foggia 《In vitro cellular & developmental biology. Plant》1987,23(4):247-252
Summary The life span and growth from clonal density of bovine adrenocortical cell cultures were studied in serum-supplemented medium
and a serum-free defined medium, which supported sustained cell proliferation and steroid production. The total culture life
span was 79 population doublings in serum-supplemented medium with fibroblast growth factor (FGF) and 36 population doublings
in the defined medium without serum. Older passage cell cultures grown in the defined medium progressively lost the ability
to produce 11β- and 21-hydroxylated steroids, which was observed previously for cultures in serum-supplemented medium, and
also had a decline of 17α-hydroxylated steroid production. The cloning efficiency in the defined medium was 12.2% as compared
to 24% in serum-supplemented medium with FGF. Five isolated clonal cell lines grown in the defined medium were characterized
for steroid function in response to steroidogenic agents. All five clonal cell lines had stimulated steroid production with
8-bromo-cAMP, but only four of the clonal lines were stimulated also by adrenocorticotropin. None of the clonal cell lines
produced 11β-, 21- or 17α-hydroxylated steroids in response to treatment with either steroidogenic agent, results that were
similar to data obtained from older mass cultures. The apparent deficiency of the defined medium as compared to serum-supplemented
medium for maximum support of the culture life span and cloning efficiency may be useful in studies of cellular aging and
its relation to differentiated function for this cell culture system.
This study was supported by the Iowa Diabetes and Endocrinology Research Center (grant AM25295 from the National Institutes
of Health, Bethesda, MD). D.A.F. was supported by a National Research Service Award from the National Institutes of Health
(grant HL07485). 相似文献
10.
Masatoshi Togami Daphne Blazka Jun Hayashi 《In vitro cellular & developmental biology. Plant》1988,24(7):699-704
Summary A serum-free, hormone and attachment factor supplemented culture for rat H4 hepatoma cells was established. In the defined
medium (Dulbecco's Modified Eagle's +Ham's F12+insulin, transferrin, fibronectin liver cell growth factor, and sodium selenite),
H4 cells grew equally well as in 10% fetal bovine serum supplemented medium. H4 cells in either defined or serum-containing
culture conditions produce transferrin but not albumin or alpha-fetoprotein. In this paper we have studied the effect of various
hormones and pressor peptides on the production of angiotensinogen by H4 cells cultured in defined conditions. Only glucocorticoid
hormone had a significant effect on the production of angiotensinogen, whereas other hormones previously reported to exert
their effect on angiotensinogen production had little or no effect.
This work was supported by grant P01 CA37589 from the National Institutes of Health, Bethesda, MD. 相似文献
11.
Di Lorenzo Teresa P. De Maro Joseph A. Pumo Dorothy E. 《In vitro cellular & developmental biology. Plant》1989,25(10):909-913
Summary A serum-free culture system was used to compare the nutritional requirements of mouse mammary cells transformed by bovine
papillomavirus type 1 (ID13 cells) and the uninfected parent line (C127 cells). The serum-free, chemically defined medium
used for this study was an MCDB 151-based medium (MCDB 151+S+I), supplemented with epidermal growth factor, transferrin, hydrocortisone,
ethanolamine, phosphoethanolamine, retinoic acid, trace metals, and insulin. Proliferation of either cell type in serum-free
culture required the addition of 250 μg/ml of insulin. ID13 cells have a doubling time of greater than 96 h in MCDB 151+S+I,
whereas C127 cells have a doubling time of 60 h. This is in sharp contrast to the growth characteristics of the two cell types
in 10% fetal bovine serum, where doubling times for the ID13 and C127 cells are 24 and 30 h, respectively. Culture of the
cells in a serum-free medium has therefore revealed that the papillomavirus-transformed cells have more stringent growth requirements
than the uninfected parent line.
This work was supported in part by grant #1-P01 NS19214 from the National Institutes of Health, Bethesda, MD, NSF grant #R11-8217798
from the National Science Foundation, Washington, DC, and by a grant from the Otolaryngology Foundation. 相似文献
12.
Although the sera used in animal cell culture media provide the macromolecules, nutrients, hormones, and growth factors necessary
to support cell growth, it could also be an obstacle to the production of recombinant proteins in animal cell culture systems
used in many sectors of the biotechnology industry. For this reason, many research groups, including our laboratory, have
been trying to develop serum-free media (SFM) or serum-supplemented media (SSM) for special or multi-purpose cell lines. The
Chinese hamster ovary (CHO) cell, for example, is frequently used to produce proteins and is especially valuable in the large-scale
production of pharmaceutically important proteins, yet information about its genome is lacking. Also, SFMs have only been
evaluated by comparing growth patterns for cells grown in SFMs with those grown in SSM or by measuring the titer of the target
protein obtained from cells grown in each type of medium. These are not reliable methods of obtaining the type of information
needed to determine whether an SFM should be replaced with an SSM. We carried out a cDNA microarray analysis to evaluate MED-3,
an SFM developed in our laboratory, as a CHO culture medium. When CHO cells were cultured in MED-3 instead of an SSM, several
genes associated with cell growth were down-regulated, although this change diminished over time. We found that the insulin-like
growth factor (IGF) gene was representative of the proteins that were down-regulated in cells cultured in MED-3. When several
key supplements-including insulin, transferrin, ethanolamine, and selenium-were removed from MED-3, theIGF expression was consistently down-regulated and cell growth decreased proportionately. Based on these results, we concluded
that when an SFM is used as a culture medium, it is important to supplement it with substances that can help the cells maintain
a high level ofIGF expression. The data presented in this study, therefore, might provide useful information for the design and development
of SFM or SSM, as well as for the design of genome-based studies of CHO cells to determine how they can be used optimally
for protein production in pharmaceutical and biomedical research. 相似文献
13.
Insulin-like growth factor I has similar mitogenic effects to insulin, a growth factor required by most cells in culture,
and it can replace insulin in serum-free formulations for some cells. Chinese Hamster Ovary cells grow well in serum-free
medium with insulin and transferrin as the only exogenous growth factors. An alternative approach to addition of exogenous
growth factors to serum-free medium is transfection of host cells with growth factor-encoding genes, permitting autocrine
growth. Taking this approach, we constructed an IGF-I heterologous gene driven by the cytomegalovirus promoter, introduced
it into Chinese Hamster Ovary cells and examined the growth characteristics of Insulin-like growth factor I-expressing clonal
cells in the absence of the exogenous factor. The transfected cells secreted up to 500 ng/106 cells/day of mature Insulin-like growth factor I into the conditioned medium and as a result they grew autonomously in serum-free
medium containing transferrin as the only added growth factor. This growth-stimulating effect, observed under both small and
large scale culture conditions, was maximal since no further improvement was observed in the presence of exogenous insulin.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
David G. Thomassen 《In vitro cellular & developmental biology. Plant》1989,25(11):1046-1050
Summary The colony-forming efficiency of rat tracheal epithelial (RTE) cells was determined in serum-free media containing different
types of commercially available bovine serum albumin (BSA): crude fraction V, essentially globulin-free, essentially fatty-acid-free,
and essentially globulin- and fatty-acid-free BSA. RTE cells exhibited a concentration-dependent increase in colony-forming
efficiency in response to crude fraction V BSA. Similar results were obtained using essentially globulin-free BSA. However,
deletion of cholera toxin from the medium resulted in a decrease in the colony-forming efficiency for cells plated in high
concentrations (>2 mg/ml) of globulin-free, but not one type of fraction V, BSA. Essentially fatty-acid-free or essentially
fatty-acid- and globulin-free BSA stimulated RTE cell colony formation at low concentrations (less than 2.5 to 5 mg BSA/ml)
but resulted in concentration-dependent decreases in colony-forming efficiency at higher concentrations. The response of cells
to these BSAs was not dependent on cholera toxin. Finally, commerically available fraction V BSA prepared by heat shock, dialysis,
charcoal treatment, and deionization was stimulatory at low concentrations but inhibitory at high concentrations. These data
suggest that impure preparations of BSA can, under different conditions, stimulate or inhibit cell proliferation and that
the expression, of these activities is affected by the method of BSA preparation, the concentration of BSA used, and, in some
cases, by the presence or absence of cholera toxin.
Research conducted with support from the Office of Health and Environmental Research, U.S. Department of Energy, Washington,
DC, under contract no. DE-AC04-76EV01013 in facilities fully acredited by the American Association for Laboratory Animal Care. 相似文献
15.
Transferrin is a major mouse milk protein and is synthesized by mammary epithelial cells 总被引:5,自引:0,他引:5
Eva Y. -H. Lee Mary Helen Barcellos-Hoff Li -How Chen Gordon Parry Mina J. Bissell 《In vitro cellular & developmental biology. Plant》1987,23(3):221-226
Summary We have identified a major mouse milk protein as transferrin (Tf) using immunoprecipitation, 2-dimensional electrophoresis,
Ouchterlony diffusion and V-8 protease digests. We show that Tf is synthesized by mammary epithelial cells themselves and
that its synthesis and secretion is regulated distinctly from that of other milk proteins. In culture, the kinetics of Tf
synthesis and secretion are distinct from that of β-casein; furthermore, Tf is relatively insensitive to lactogenic hormones
whereas β-casein is hormone-dependent.In vivo, however, Tf is regulated by pregnancy. While the virgin gland produces small amounts of Tf, its production is greatly increased
during pregnancy and lactation. Thus, Tf synthesis in the mammary gland is modulated by as yet unknown factorsin vivo. These observations are discussed in terms of Tf’s possible role in mammary gland growth, differentiation and function.
This research was supported by the OHER office of U. S. DOE, contract DE-AC 03-76S F00098, and NIH grant BRSG RR05918.
Editor’s Statement This study combines cultured cells and direct analytical approaches to show that authentic transferrin
is a major mouse milk protein and is regulated differently than beta-casein in mammary epithelium. Wallace L. McKeehan 相似文献
16.
In order to establish a simple and scaleable transfection system we have used the cationic polymer polyethylenimine (PEI)
to study transient transfection in HEK293 and 293(EBNA) cells grown in serum-free suspension culture. The transfection complexes
were made directly within the cell culture by consecutively adding plasmid and PEI (direct method). Alternatively, the DNA-PEI
transfection complexes were prepared in fresh medium (1/10 culture volume) and then added to the cells (indirect method).
The results of this study clearly show that the ratio of PEI nitrogen to DNA phosphate is very important for high expression
levels. The precise ratio is dependent on the DNA concentration. For example, using 1 μg/ml DNA by the indirect method, the
ratio of optimal PEI:DNA was about 10–13:1. However, the ratio increases to 33:1 for 0.1–0.2 μg/ml DNA. By testing several
different molecular weights of the polycationic polymer we could show that the highest transfection efficiency was obtained
with the PEI 25 kDa. Using PEI 25 kDa the indirect method is superior to the direct addition because significantly lower DNA
concentrations are needed. The expression levels of the soluble human TNF receptor p55 are even higher at low DNA compared
to 1 μg/ml plasmid. The EBV-based pREP vectors gave better transient gene expression when used in 293(EBNA) cells compared
to HEK293 cells in suspension culture. No differences in expression levels in the two cell lines were observed when the pC1
(CMV)-TNFR was used. In conclusion, PEI is a low-toxic transfection agent which provides high levels of transient gene expression
in 293(EBNA) cells grown in serum-free suspension culture. This system allows highly reproducible, cost-effective production
of milligram amounts of recombinant proteins in 2–5 l spinner culture scale within 3–5 days. Fermentor scale experiments,
however, are less efficient because the PEI-mediated transient tranfection is inhibited by conditioned medium.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Michel Moenner Elissavet Hatzi Josette Badet 《In vitro cellular & developmental biology. Animal》1997,33(7):553-561
Summary The requirement of serum in cell culture is a major limitation for studies on secreted ribonucleases (RNases) because serum
contains a high amount of ribonucleolytic activity. Defined culture condition is thus of interest to improve our knowledge
of the RNase biology. We report here that cells from three different types and origins, Chinese hamster lung fibroblasts,
bovine smooth muscle cells, and human endothelium-derived EA.hy926 cells, proliferate consistently in the presence of a basal
medium supplemented with bovine serum albumin, high-density lipoproteins, basic fibroblast growth factor, insulin, and transferrin.
Using a new quantitative radio-RNase inhibitor assay, two distinct ribonucleolytic assays, and a radioimmunoassay against
angiogenin, it is shown that RNases became apparent in media conditioned by cell monolayers. Both the hamster lung fibroblast
and the EA.hy926 cell lines secreted larger amounts of RNase inhibitor-interacting factors and RNase activity than normal
smooth muscle cells. The serum-free medium represents an alternative way to grow these cells and allows investigation of biosynthesis
and functions of RNases in culture. It should be useful to identify and quantitate unambiguously specific members of the RNase
family secreted by normal versus tumor cells in culture. 相似文献
18.
Supernatant proteolytic activities of High-Five insect cells grown in serum-free culture 总被引:2,自引:0,他引:2
L. Ikonomou C. Peeters-Joris Y.-J. Schneider S.N. Agathos 《Biotechnology letters》2002,24(12):965-969
The proteolytic activity of High-Five insect cell culture supernatants was analysed using substrate gel electrophoresis (zymography). During growth in serum-free media, High-Five cells constitutively expressed and secreted proteases that were active on casein gel but not on gelatin or bovine serum albumin gels. Two main protease bands were visible at about 41–42 kDa and 32–33 kDa. By addition of various protease inhibitors in the incubation buffer, the proteases were identified as metalloproteases as complete and specific inhibition of the proteolytic activities was only obtained by 1,10-phenanthroline. 相似文献
19.
Polypeptide growth factors, including members of the fibroblast growth factor (FGF) family, play an important role in the growth and maintenance of the normal prostate. We have found that FGF9 is expressed at high levels in the normal peripheral and transition zone of the human prostate. Analysis of FGF9 production by primary cultures of prostatic epithelial and stromal cells has shown that FGF9 is produced and secreted by the prostatic stromal cells. Neither of these processes appears to be modulated by androgens. Production of FGF9 by stromal cells in vivo was confirmed by immunohistochemistry. FGF9 is a potent mitogen for both prostatic epithelial and stromal cells in culture and is a more potent mitogen for these cells than either FGF2 or FGF7, two other FGFs expressed in the human prostate. FGF9 is an abundant secreted growth factor that can act as both a paracrine mitogen for epithelial cells and an autocrine mitogen for stromal cells. Western blot analysis of tissue extracts from the normal and hyperplastic transition zone shows that FGF9 is present at two to threefold higher levels in the hyperplastic transition zone. Overexpression of this paracrine and autocrine growth factor may play an important role in the epithelial and stromal proliferation in benign prostatic hyperplasia. J. Cell. Physiol. 180:53–60, 1999. © 1999 Wiley-Liss, Inc. 相似文献
20.
Adaptation of mammalian cells to growth in serum-free media 总被引:5,自引:0,他引:5
A three-step protocol is described for adapting an anchorage-dependent, serum-dependent recombinant mammalian cell lineage
to high density serum-free suspension culture. The objective is a cell lineage that is well-suited for the manufacture of
a recombinant protein. The first step of the protocol generates an anchorage-independent cell lineage by culturing trypsin-treated
cells in spinner flasks using serum-containing medium. The second step adapts the lineage to serum-free medium through a series
of serum reduction steps in the presence of defined growth-promoting additives. The third step adapts the lineage to high-cell-density
conditions by culturing the cells in a bioreactor in a manner that allows development of tolerance to growth-inhibiting substances
released by the cells. Examples are presented for the use of this protocol for recombinant CHO cells. 相似文献