共查询到20条相似文献,搜索用时 15 毫秒
1.
Kannan RY Salacinski HJ Sales KM Butler PE Seifalian AM 《Cell biochemistry and biophysics》2006,45(2):129-136
It has been recognized that seeding vascular bypass grafts with endothelial cells is the ideal method of improving their long-term
patency rates. The aim of this study was to assess the in vitro cytocompatibility of a novel silica nanocomposite, polyhedral
oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) and hence elicit its feasibility at the vascular interface
for potential use in cardiovascular devices such as vascular grafts. Using primary human umbilical vein endothelial cells
(HUVEC), cell viability and adhesion were studied using AlamarBlue assays, whereas cell proliferation on the polymer was assessed
using the PicoGreen dye assay. Cellular confluence and morphology on the nanocomposite were analyzed using light and electron
microscopy, respectively. Our results showed that there was no significant difference between cell viability in standard culture
media and POSS-PCU. Endothelial cells were capable of adhering to the polymer within 30 min of contact (Student's t-test, p<0.05) with no difference between POSS-PCU and control cell culture plates. POSS-PCU was also capable of sustaining good cell
proliferation for up to 14d even from low seeding densities (1.0×103 cells/cm2) and reaching saturation by 21 d. Microscopic analysis showed evidence of optimal endothelial cell adsorption morphology
with the absence of impaired motility and morphogenesis. In conclusion, these results support the application of POSS-PCU
as a suitable biomaterial scaffold in bio-hybrid vascular prostheses and biomedical devices. 相似文献
2.
L W Hayes C A Goguen S F Ching L L Slakey 《Biochemical and biophysical research communications》1978,82(4):1147-1153
The activity of angiotensin converting enzyme has been measured in endothelial cells cultured from hog aorta, and in serum-free culture medium taken from both endothelial cells and smooth muscle cells. Endothelial cells maintained in medium containing 20% fetal calf serum contained 43 pmol/min/106 cells of converting enzyme activity; freshly collected cells contained 518 pmol/min/106 cells. Endothelial cells held in serum-free medium release this activity into the medium in amounts up to 40 times that associated with the cells; at the same time the activity associated with the cells rises 2 fold. The rise in cell-associated activity and the appearance of activity in the medium are both blocked by cycloheximide. These observations provide direct evidence that endothelial cells can produce excess angiotensin-converting enzyme and release it in active form, and thus serve as the source of circulating converting enzyme activity. 相似文献
3.
R. Pörtner M. Matsumura T. Hatae K. Murakami H. Kataoka 《Bioprocess and biosystems engineering》1991,7(1-2):63-69
A recombinant CHO cell line producing human prorenin was cultivated on microcarriers in serum-free medium. Best growth was obtained when the cells were cultivated on a collagen coated microcarrier (Cytodex 3) using a serum-free medium (SF-02) supplemented with fibronectin. It was possible to reduce the necessary concentration of fibronectin in the feed medium from 10 g/cm3 to 2 g/cm3 during perfusion cultures in a spinner reactor equipped with an UF-membrane. Also in this system, the prorenin concentration increased up to 8 times higher compared to that in a conventional repeated-batch culture. The cells grew in multilayers on the microcarriers during the perfusion culture. The specific prorenin productivity was not significantly affected by the cell growth rate, and the secretion of prorenin continued even after the cells had ceased to grow. 相似文献
4.
Mohamadreza Baghaban Eslaminejad Samad Nadri 《In vitro cellular & developmental biology. Animal》2009,45(8):451-459
Marrow culture from mice has been reported to be overgrown by non-mesenchymal cells. In almost all protocols for isolation
of murine mesenchymal stem cells (MSCs), high density culture systems have been employed. Since MSCs are colonogenic cells,
the initiating cell seeding density may have significant impact on their cultures. This subject was explored in this study.
For this purpose, the bone marrow cells from NMRI mice were plated at 2.5 × 106 cells/cm2 and upon confluency were reseeded as either low density (50 cells/cm2) or high density (8 × 104 cells/cm2) cultures. The cells were expanded through an additional subculture and the passage 2 cells as a product of two culture systems
were statistically compared with respect to their surface antigen profiles and osteogenic culture mineralization. While low
density culture grew with multiple colony formation, there were no distinct colonies in high density cultures. In contrast
to high density cultures, passage 2 cells from low density system possessed typical homogenous fibroblastic morphology. Some
cells from high density system but not the low density cultures expressed hematopoietic and endothelial cell markers including
CD135, CD34, CD31, and Vcam surface antigens. Furthermore, osteogenic cultures from low density system displayed significantly
more mineralization than those from high density system. Taken together, it seems that low density culture system resulted
in more purified MSC culture than its counterpart as high density culture system. 相似文献
5.
Yang Lu Yiyi Gong Jie Lian Ling Wang James D. Kretlow Guangdong Zhou Yilin Cao Wei Liu Wen Jie Zhang 《PloS one》2014,9(9)
In vitro expansion of endothelial progenitor cells (EPCs) remains a challenge in stem cell research and its application. We hypothesize that high density culture is able to expand EPCs from bone marrow by mimicking cell-cell interactions of the bone marrow niche. To test the hypothesis, rat bone marrow cells were either cultured in high density (2×105 cells/cm2) by seeding total 9×105 cells into six high density dots or cultured in regular density (1.6×104 cells/cm2) with the same total number of cells. Flow cytometric analyses of the cells cultured for 15 days showed that high density cells exhibited smaller cell size and higher levels of marker expression related to EPCs when compared to regular density cultured cells. Functionally, these cells exhibited strong angiogenic potentials with better tubal formation in vitro and potent rescue of mouse ischemic limbs in vivo with their integration into neo-capillary structure. Global gene chip and ELISA analyses revealed up-regulated gene expression of adhesion molecules and enhanced protein release of pro-angiogenic growth factors in high density cultured cells. In summary, high density cell culture promotes expansion of bone marrow contained EPCs that are able to enhance tissue angiogenesis via paracrine growth factors and direct differentiation into endothelial cells. 相似文献
6.
Macrovascular endothelial cells isolated from the human umbilical vein and microvessel endothelium from the newborn foreskin dermis differ in their requirements for optimal growth in vitor. In the presence of 5 x 10?4 M dibutyryl cyclic AMP (Bt2cAMP), human dermal microvessel endothelial cell proliferation rate increased to give a cell number of 203% of control values by day 10 in culture. The cells retained their characteristic endothelial cell morphology, reached confluence, and could be serially passaged. Cells grown in the absence of Bt2cAMP did not proliferate readily and grew in a disorganized pattern. The effect of Bt2cAMP on microvascular endothelial cell proliferation rate and morphology could be duplicated by cholera toxin (CT) used together with isobutyl methyl-xanthine (IMX). These agents were found to elevate intracellular levels of cyclic AMP in microvascular endothelium over 40-fold. Human umbilical vein cells in culture failed to respond to either Bt2cAMP or CT together with IMX. The growth-promoting effect of dibutyryl cyclic AMP (Bt2cAMP) on human foreskin dermal microvascular endothelium in vitro is in marked contrast to the lack of response of human umbilical vein cells. These results provide further evidence of differences in the mechanisms that regulate macro and microvessel endothelial cell proliferation in vitro. 相似文献
7.
Taku Matsushita Hiromichi Hidaka Ken-ichi Kamihata Yasuhiko Kawakubo Kazumori Funatsu 《Applied microbiology and biotechnology》1991,35(2):159-164
Summary Monkey kidney cells (Vero) and Chinese hamster ovary cells (CHO-K1) attached to the internal surface of polyurethane foam (PUF) and grew to a high cell density (1.1 × 108 cells/cm3 PUF and 4.2 × 107 cells/cm3 PUF, respectively) in a PUF-plates packed-bed culture system. This density of Vero cells was twice that obtained previously with a PUF-particles packed-bed culture system. A maximum cell density of 6.7 × 107 cells/cm3 culture vessel volume was obtained in a PUF-disc packed-bed culture of Vero cells. From the cell density of CHO-K1, growing in a monolayer on the surface of PUF and a petri dish, per bulk volume of PUF, we estimated that a surface area to volume ratio of PUF plates effective for cell growth was about 109 cm2/cm3.Offprint requests to: K. Funatsu 相似文献
8.
Hydroxyapatite-pulp composite fiber sheet bed: A new material for the immobilization of CHO-K1 cells
A new immobilization material for cell culture, ahydroxyapatite-pulp composite fiber (HAPC) sheet bed, was usedto grow CHO-K1 cells. The sheet bed for cell culture wasprepared from HAPC fiber by paper-making techniques. Scanning electron microscopic analysis revealed that the HAPCsheet bed had a structure consisting of piled fibers with spaces 10–200 m in diameter and a pore surface area of 0.32 m2 g-1. Using a 25 × 25 mm2 squareHAPC sheet bed 0.41 mm in thickness (85 g m-2 basis weight) for cell culture, CHO-K1 cells grew to a cell densityof 3.7 × 107 cells cm-3 in a 60 mm plastic dish over a 6-day culture period. High-density culture of CHO-K1 cells was successfully performed using the HAPC sheet bed in a 500 ml spinner flask over a 21-day culture period. The HAPC sheet bed, wound around the stirrer paddle, was rotated in the spinner flask in order to supply nutrientsand remove waste products efficiently. The HAPC sheet bedhas a large surface area to support cell growth and there islarge diffusion space inside of the bed. This newautoclavable substrate for anchorage-dependent cells can be easily scaled-up. 相似文献
9.
Endothelial cells derived from human pulmonary arteries incorporate (3H)-glucosamine and 35SO4 into glycosaminoglycans and into the carbohydrate side chains of glycoproteins. These 3H/35S-carbohydrate chains were isolated from cells and culture medium after Pronase digestion. The 3H/35S-glycosaminoglycans were separated from the 3H/35S glycopeptides by chromatography on Sephadex G-50. The distribution of cellular glycosaminoglycans and glycopeptides indicated that 30–60% of the cellular 35S-glycopeptides may be associated with the matrix components that are synthesized by the cell and attached to a plastic substratum. Human pulmonary arterial endothelial cells were grown on collagen or on a matrix derived from vascular smooth muscle cells in order to investigate how smooth muscle cell extracellular matrix components may regulate the synthesis of endothelial cell glycoconjugates. Endothelial cells grown on plastic release various proportions of the glycoconjugates they synthesize into the culture medium. However, these same cells, when grown on substratum composed of extracellular matrix materials, synthesized altered proportions of cell-associated glycosaminoglycans and reduced the levels of total glycosaminoglycans they released into the culture medium. Thus the growth of endothelial cells on a matrix of smooth muscle cell components indicates that the glycosaminoglycan materials released into the culture medium by cells grown on a plastic substratum may not be an accurate reflection of the levels or composition of extracellular matrix materials made by endothelial cells in vivo. 相似文献
10.
Isolation and long-term serial cultivation of endothelial cells from the microvessels of the adult human dermis 总被引:1,自引:0,他引:1
P. M. Davison K. Bensch M. A. Karasek 《In vitro cellular & developmental biology. Plant》1983,19(12):937-945
Sumamry A method to isolate and maintain microvascular endothelial cells from the cutaneous vessels of adult human skin in long-term
culture has been developed. Endothelial cells lining the microvessels of the papillary dermis are released from surrounding
tissue during a brief trypsin incubation (0.3% trypsin, 1% EDTA). Cells are plated onto a fibronectin substrate and maintained
in Leibovitz (L15) culture medium containing pooled human serum (50%) and antibiotics. Proliferation is dependent upon the
presence of several additional growth factors, cholera enterotoxin (1×10−9
M), isobutyl methylxanthine (3.3×10−5
M), and medium conditioned by explant culture of the mouse EHS sarcoma. Using this supplemented medium, cells proliferate readily
and can be cultivated serially for more than 6 passages (3 months in vitro). These cells retain their characteristic endothelial
cell morphology, stain positively for Factor VIII antigen, and contain Weibel-Palade bodies.
This research was supported by grant AG 01312 from the U.S. Public Health Service, Washington, D.C. 相似文献
11.
Taku Matsushita Masayoshi Ketayama Ken-ichi Kamihata Kazumori Funatsu 《Applied microbiology and biotechnology》1990,33(3):287-290
Summary Anchorage-dependent mammalian cells were cultivated at high cell density in a novel culture system using polyurethane foam (PUF) as a substratum for cell attachment. PUF has a macroporous structure giving a high surface area to volume ratio. Monkey kidney cells (Vero) and Chinese hamster ovary cells (CHO-K1) attached to the internal surface of PUF and grew to a high cell density (1.04 × 108 cells/ cm3 PUF and 3.5 × 107 cells/ cm3 PUF, respectively) in PUF stationary cultures. In addition, we have designed a PUF-particle packed-bed culture system for high density mass cell culture. A maximum cell density of 2.4 × 107 cells/cm3 culture vessel volume was obtained in a packed-bed culture of Vero cells.
Offprint requests to: K. Funatsu 相似文献
12.
CD34+VEGFR‐3+ progenitor cells have a potential to differentiate towards lymphatic endothelial cells
Yu‐zhen Tan Hai‐jie Wang Mei‐hua Zhang Zhe Quan Ting Li Qi‐zhi He 《Journal of cellular and molecular medicine》2014,18(3):422-433
Endothelial progenitor cells (EPCs) play an important role in postnatal neovascularization. However, it is poorly understood whether EPCs contribute to lymphangiogenesis. Here, we assessed differentiation of a novel population of EPCs towards lymphatic endothelial cells and their lymphatic formation. CD34+VEGFR‐3+ EPCs were isolated from mononuclear cells of human cord blood by fluorescence‐activated cell sorting. These cells expressed CD133 and displayed the phenotype of the endothelial cells. Cell colonies appeared at 7–10 days after incubation. The cells of the colonies grew rapidly and could be repeatedly subcultured. After induction with VEGF‐C for 2 weeks, CD34+VEGFR‐3+ EPCs could differentiate into lymphatic endothelial cells expressing specific markers 5′‐nucleotidase, LYVE‐1 and Prox‐1. The cells also expressed hyaluronan receptor CD44. The differentiated cells had properties of proliferation, migration and formation of lymphatic capillary‐like structures in three‐dimensional collagen gel and Matrigel. VEGF‐C enhanced VEGFR‐3 mRNA expression. After interfering with VEGFR‐3 siRNA, the effects of VEGF‐C were diminished. These results demonstrate that there is a population of CD34+VEGFR‐3+ EPCs with lymphatic potential in human cord blood. VEGF‐C/VEGFR‐3 signalling pathway mediates differentiation of CD34+VEGFR‐3+ EPCs towards lymphatic endothelial cells and lymphangiogenesis. Cord blood‐derived CD34+VEGFR‐3+ EPCs may be a reliable source in transplantation therapy for lymphatic regenerative diseases. 相似文献
13.
《Cell Adhesion & Migration》2013,7(5):517-524
Endothelial cells lining blood vessels are exposed to various hemodynamic forces associated with blood flow. These include fluid shear, the tangential force derived from the friction of blood flowing across the luminal cell surface, tensile stress due to deformation of the vessel wall by transvascular flow, and normal stress caused by the hydrodynamic pressure differential across the vessel wall. While it is well known that these fluid forces induce changes in endothelial morphology, cytoskeletal remodeling, and altered gene expression, the effect of flow on endothelial organization within the context of the tumor microenvironment is largely unknown. Using a previously established microfluidic tumor vascular model, the objective of this study was to investigate the effect of normal (4 dyn/cm2), low (1 dyn/cm2), and high (10 dyn/cm2) microvascular wall shear stress (WSS) on tumor-endothelial paracrine signaling associated with angiogenesis. It is hypothesized that high WSS will alter the endothelial phenotype such that vascular permeability and tumor-expressed angiogenic factors are reduced. Results demonstrate that endothelial permeability decreases as a function of increasing WSS, while co-culture with tumor cells increases permeability relative to mono-cultures. This response is likely due to shear stress-mediated endothelial cell alignment and tumor-VEGF-induced permeability. In addition, gene expression analysis revealed that high WSS (10 dyn/cm2) significantly down-regulates tumor-expressed MMP9, HIF1, VEGFA, ANG1, and ANG2, all of which are important factors implicated in tumor angiogenesis. This result was not observed in tumor mono-cultures or static conditioned media experiments, suggesting a flow-mediated paracrine signaling mechanism exists with surrounding tumor cells that elicits a change in expression of angiogenic factors. Findings from this work have significant implications regarding low blood velocities commonly seen in the tumor vasculature, suggesting high shear stress-regulation of angiogenic activity is lacking in many vessels, thereby driving tumor angiogenesis. 相似文献
14.
In the present study we investigate the fibrin(ogen)-endothelial cell binding and the effect of thrombin on the endothelial cells in relation to fibrin(ogen) binding capacity. Endothelial cell fibrinogen binding was concentration and time-dependent, reaching saturation at 1.4 M of added ligand. At equilibrium, the number of fibrinogen molecules bound per endothelial cell in the monolayer was 5.8±0.7×106. When endothelial cells were activated by different concentrations of thrombin (0–0.1 NIH units ml–1), no increase in fibrinogen binding capacity was observed at all the thrombin concentration tested. Whereas disruption of endothelial cell monolayers was observed at thrombin concentrations higher than 0.05 NIH units ml–1, no increase in the amount of fibrinogen bound was observed. Therefore, resting and thrombin-activated endothelial cells show the same fibrinogen binding capacity.The adhesion of endothelial cells in suspension on immobilized fibrinogen or fibrin was studied to ascertain whether the behavior of fibrin is similar to that of fibrinogen. The extent of endothelial cell attachment to immobilized fibrinogen and fibrin was similar (4275±130 cells cm–2 for fibrinogen and 4350±235 cells cm–2 for fibrin) and represent approximately 40% of the added endothelial cells. However, endothelial cell adhesion to immobilized fibrin was significantly faster than endothelial cell adhesion to immobilized fibrinogen. The maximum binding rate was 66±9 and 46±8 cells cm–2 min–1 for fibrin and fibrinogen, respectively. Therefore, the fibrinopeptides released by thrombin from fibrinogen induce qualitative changes which enhance the fibrin interaction with the endothelial cells. 相似文献
15.
Separation and in vitro growth of mammalian corneal epithelial and endothelial cells 总被引:3,自引:0,他引:3
A double Rose chamber technique is described for simultaneously separating the endothelial and epithelial cells from the corneas of a variety of animals. Endothelial cells, although few in number at harvest, quickly grew into thriving cultures. Epithelial cells, although obtained in large numbers from the corneas, were more difficult to establish and grow. These two types of cells from one tissue differ greatly in culture and are useful materials for various comparative studies. Cells from X-irradiated animals produced multinucleated gaint cells and abnormal fibroblastic cells. 相似文献
16.
Growing evidence suggests that the phenotype of endothelial cells during angiogenesis differs from that of quiescent endothelial cells, although little is known regarding the difference in the susceptibility to inflammation between both the conditions. Here, we assessed the inflammatory response in sparse and confluent endothelial cell monolayers. To obtain sparse and confluent monolayers, human umbilical vein endothelial cells were seeded at a density of 7.3×103 cells/cm2 and 29.2×103 cells/cm2, respectively, followed by culturing for 36 h and stimulation with tumor necrosis factor α. The levels of tumor necrosis factor α-induced E-selectin protein and mRNA expression were higher in the confluent monolayer than in the sparse monolayer. The phosphorylation of c-jun N-terminal kinase and p38 mitogen-activated protein kinase or nuclear factor-κB activation was not involved in this phenomenon. A chromatin immunoprecipitation assay of the E-selectin promoter using an anti-acetyl-histone H3 antibody showed that the E-selectin promoter was highly and specifically acetylated in the confluent monolayer after tumor necrosis factor α activation. Furthermore, chromatin accessibility real-time PCR showed that the chromatin accessibility at the E-selectin promoter was higher in the confluent monolayer than in the sparse monolayer. Our data suggest that the inflammatory response may change during blood vessel maturation via epigenetic mechanisms that affect the accessibility of chromatin. 相似文献
17.
Various polypeptide growth factors, culture substrates, basal media, sera and further supplements were assayed for improvement of growth of human vascular endothelial cells from umbilical cord veins. The resulting optimized medium consisted of gelatinized culture substrates, a mixture (1:1) of Iscove's MDM and Ham's F12 basal media supplemented with 20% newborn calf serum, 500 ng/ml crude fibroblast growth factor, 20 ng/ml epidermal growth factor, 5 g/ml transferrin, 5 g/ml insulin and 10 g/ml heparin. The medium allowed long term cultivation of HUVEC up to 45 generations with maximal cell densities of about 105 cells per cm2 and a minimal doubling time of about 14 hours at low cell densities.Abbreviations HUVEC
Human Endothelial Cells From Umbilical Cord Veins
- FGF
Fibroblast growth factor
- EGF
Epidermal Growth Factor
- FCS
Fetal Calf Serum
- NCS
Newborn Calf Serum
- HBS
HEPES-Buffered Saline
- ECM
Extracellular Matrix
- LHM
Peptide PyroGlu-His-Ser-Phe-Thr-Ile-Lys-Ile-ThrCONH2
- IF
1:1 mixture of Iscove's MDM and F12 basal media 相似文献
18.
Koichi Hirata Tadashi Oku Aaron E. Freeman 《In vitro cellular & developmental biology. Plant》1982,18(9):789-799
Summary Twenty to twenty-two days postcoitum mouse fetal pancreas organ bits were cultured on the dermal surface of irradiated pigskin
as a substrate. The medium used for long term culture consisted of Eagle’s Minimum Essential Medium with the addition of 10%
bovine serum, 0.02 U/ml insulin, 0.025 μg/ml glucagon, 3.63 μg/ml hydrocortisone, 100 μg/ml soybean trypsin inhibitor or 10−8
M atropine. When the medium lacked trypsin inhibitor or atropine but contained the three hormones, the pigskin support began
to be destroyed after 2 to 4 wk in culture. Thereafter, the cultured cells could not grow and survive on the digested pigskin.
When 10−6
M atropine was added to the medium, amylase secretion from cultured cells and destruction of pigskin were inhibited completely
but pancreas cells could not grow or survive. In contrast, 100 μg/ml soybean trypsin inhibitor or 10−8
M atropine permitted cell growth, permitted amylase secretion from the cultured acinar cells, and prevented the destruction
of pigskin. Under these conditions pancreas cells migrated or grew or both from the organ bits onto the surface of the pigskin
dermis and organoid aggregations formed. Hydrocortisone was needed to permit growth for more than 2 wk. Glucagon and insulin
had additive effects. Light and electron microscopic observations indicated the culture of at least five kinds of cells, i.e.,
duct, acinar, centroacinar, endocrine, and mesenchymal. The majority of cultured cells were duct cells and acinar cells. There
were few mesenchymal cells. Mouse pancreas cells were cultured for at least 12 wk by this method.
This investigation was supported by PHS Grant CA 30220 awarded by the National Cancer Institute, DHHS, Grant 1203M awarded
by the Council for Tobacco Research, Inc., and Grant RD-65 (for equipment) awarded by the American Cancer Society. Nude mice
were provided by Dr. Wendall M. Farrow of Life Sciences, Inc., Resource Laboratory N01, CP6-1005 of the National Cancer Institute. 相似文献
19.
Analysis of lymphocytes reactive to histocompatibility antigens. II. Exponential alloantigen-dependent lymphocyte growth in vitro 总被引:1,自引:0,他引:1
Rat thoracic duct lymphocytes were maintained in continual blast transformation and cell division by repeated in vitro stimulation with allogeneic cells. This resulted in increases in responder cell numbers of up to 10,000-fold in 10-day periods. Growth of responder lymphocyte populations was dependent upon cell density, culture medium nutrients, and the presence of antigen in the form of allogeneic cells. A titration assay for mixed lymphocyte interactions (MLI) was used to relate absolute growth of cells in preparative cultures to [3H]thymidine incorporation in analytical MLI. Growth of lymphocyte populations derived by repeated stimulation with cells bearing a single foreign MHC haplotype was supported to lesser, variable degrees by stimulation with unrelated “third party” stimulator cells. The extent of this operational cross-reactivity was assessed by parallel line analysis of MLI titrations of responder lymphocytes enriched for specific alloreactivity. 相似文献
20.
Robert H. Whitehead Anthony Brown Prithi S. Bhathal 《In vitro cellular & developmental biology. Plant》1987,23(6):436-442
Summary Little is known concerning the biological factors that control the proliferation of the stem cells of the colonic mucosa.
In part this is due to a lack of systems suitable for studying the proliferation of this mucosa in vitro. We describe a simple
technique for the isolation of single viable intact crypts which are free of stroma and which can then be cultured for periods
of at least 16 d using a collagen gel culture method. This method of crypt isolation was efficient with the mean yield of
viable intact crypts being 1.4 ±1.2×104 (
± SD) crypts/cm2 of mucosa. In culture, mucosal cells only survived for extended periods when the crypts were cultured in collagen gels over
a feeder layer of bovine aortic endothelial cells. Cells containing mucus were present in the cultured crypts at all stages
of the culture; however we have not been able to demonstrate alkaline phosphatase activity in these crypts. Studies of DNA
synthesis after 7 d in culture, using a 18-h pulse label with bromodeoxyuridine (BUdR) has shown that DNA synthesis, as measured
by incorporation of BUdR into nuclei, is still occurring in these cultured crypts. 相似文献