scholarly journals Effect of Growth Factors on Bovine Blastocyst Development in a Serum-Free Medium

1994 ◽  
Vol 35 (2) ◽  
pp. 141-147
Author(s):  
M. Shamsuddin
Keyword(s):  
Growth Factors ◽  
Serum Free Medium ◽  
Free Medium ◽  
Blastocyst Development ◽  
Serum Free ◽  
Bovine Blastocyst

scholarly journals The effects of various hormones and growth factors on the growth of human insulin-producing cell line in serum-free medium

1997 ◽  
Vol 29 (4) ◽  
pp. 209-216 ◽  
Author(s):  
Jae-Jeong Lee ◽  
Jai-Hyun Kwon ◽  
Yong Keun Park ◽  
Ohoak Kwon ◽  
Tai-Wook Yoon
Keyword(s):  
Growth Factors ◽  
Cell Line ◽  
Human Insulin ◽  
Serum Free Medium ◽  
Free Medium ◽  
Serum Free

Effect of Growth Factors on Growth of Bovine Parathyroid Cells in Serum-Free Medium

1996 ◽  
Vol 20 (7) ◽  
pp. 822-829 ◽  
Author(s):  
Gregory P. Sadler ◽  
Derek L. Jones ◽  
J. Stuart Woodhead ◽  
Kieran Horgan ◽  
Malcolm H. Wheeler
Keyword(s):  
Growth Factors ◽  
Serum Free Medium ◽  
Free Medium ◽  
Serum Free

Orientation and directed migration of cultured corneal epithelial cells in small electric fields are serum dependent

1996 ◽  
Vol 109 (6) ◽  
pp. 1405-1414 ◽  
Author(s):  
M. Zhao ◽  
A. Agius-Fernandez ◽  
J.V. Forrester ◽  
C.D. McCaig
Keyword(s):  
Growth Factors ◽  
Electric Field ◽  
Electric Fields ◽  
Single Cells ◽  
Serum Free Medium ◽  
Free Medium ◽  
Corneal Epithelial ◽  
Serum Free ◽  
Directed Migration ◽  
Serum Dependent

Reorientation and migration of cultured bovine corneal epithelial cells (CECs) in an electric field were studied. Electric field application was designed to model the laterally directed, steady direct current electric fields which arise in an injured corneal epithelium. Single cells cultured in media containing 10% foetal bovine serum showed significant galvanotropism, reorienting to lie perpendicular to electric field vector with a threshold field strength of less than 100 mV/mm. Cells cultured in serum-free medium showed no reorientation until 250 mV/mm. Addition of EGF, bFGF or TGF-beta 1 singly or in combination to serum free medium significantly restored the reorientation response at low field strengths. Both the mean translocation rate and directedness of cell migration were serum dependent. Cultured in medium with serum or serum plus added EGF, single cells showed obvious cathodal migration at 100 mV/mm. Increasing electric field strength enhanced the cathodal directedness of single cell migration. Supplementing serum free medium with growth factors restored the cathodal directed migration of single cells and highest directedness was found for the combination of EGF and TGF-beta 1. Corneal epithelial sheets also migrated towards the cathode in electric fields. Serum or individual growth factors stimulated CEC motility (randomly directed). Applied fields did not further augment migration rates but added a vector to stimulated migration. Electric fields which are present in wounded cornea interact with other environmental factors and may impinge on CECs migration during wound healing. Therapies which combine the application of growth factors and electric fields may be useful clinically.

Expression of PRV-1 Decreases Dependency of Cells on Growth Factors for Proliferation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 655-655
Author(s):  
Vahid Afshar-Kharghan ◽  
Jun Li ◽  
Zakar Mnjoyan
Keyword(s):  
Growth Factors ◽  
Cho Cells ◽  
Growth Media ◽  
Maximal Effect ◽  
Serum Free Medium ◽  
Free Medium ◽  
Transfected Cells ◽  
Serum Free ◽  
Cell Lysate ◽  
Cpg Dinucleotide

Abstract Polycythemia rubra vera-1 (PRV-1) is a GPI-linked protein expressed on surface of neutrophils. Polycythemia vera and essential thrombocythemia were found to be associated with an increase in the level of PRV-1 mRNA; however, the function of PRV-1 remains unknown. We have studied the functional effect of expression of PRV-1, both in heterologous cell line and in neutrophils. cDNA encoding PRV-1 was subcloned from a leukocyte cDNA library and expressed in Chinese hamster ovary cells (CHO). After seeding equal numbers of CHO cells stably transfected with PRV-1 or empty plasmid, cell count was conducted at different time intervals and under different concentration of fetal bovine serum (FBS) in growth media. The numbers of PRV-1 transfected cells were higher than sham-transfected cells at 24, 48, 96 and 144 hrs after seeding, and this difference was enhanced with cells growing in a medium with a reduced concentration of serum with the maximal effect seen in serum-free medium. The percentage of apoptotic cells was similar between PRV-1 and sham-transfected cells. These results are suggestive of that CHO cells expressing PRV-1 proliferate faster than sham-transfected cells. The difference in proliferation rate was more significant at lower concentrations of serum and was the highest in serum-free medium. An immunoblot analysis with anti-phosphotyrosine antibody on the whole cell lysate demonstrated that the presence of PRV-1 alters cell signaling. A 60kDa protein band that disappeared after removal of serum in growth medium of sham-transfected cells continued to be present in the PRV-1 transfected cell lysate regardless of the presence or absence of FBS in the media. In order to understand the function of PRV-1 in neutrophils, we used the fact that in 85% of individuals PRV-1 is expressed only by a subgroup of neutrophils. We separated PRV-1 expressing neutrophils of an individual from those lacking this protein in the same donor, using anti-PRV-1 monoclonal antibody. We then compared the gene expression profile of the two groups of neutrophil using DNA microarray technique. Expression of PRV-1 was associated with several folds increase in expression of growth factors (fracture callus-1, X 14.9 times; Insulin-like 3, X 6.7; neural proliferation differentiation, and control-1 or NPDC1, X 3.4 times) and post-translational modifying enzyme of cell surface protein (N-acetylase N sulfotransferase-1, X 18.9 times). Under physiologic conditions, transcriptional regulation of the PRV-1 gene limits its expression to only a certain percentage of neutrophils. In order to investigate the role of epigenetic factors in regulation of transcription of the PRV-1 gene, we analyzed methylation of CpG dinucleotide in promoter of the PRV-1 gene in the genomic DNA obtained from neutrophils expressing PRV-1 to those that don’t express this protein in the same individual. Expression of PRV-1 was associated with a decrease in methylation of the CpG dinucleotide located 2937 bp before initiation codon (45% methylated in PRV-1 negative neutrophils compared to 30% methylated in PRV positive neutrophils). We are currently studying the methylation pattern of CpG islands inside the PRV-1 gene. Studying the effect of DNA methylation on expression of PRV-1 in physiologic conditions, may shed light to the mechanism of overexpression of PRV-1 in MPD.

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