Conditioned medium factor

CbfA C-module-binding factor CMF conditioned medium factor... 

L3. Lyons, R. M., Keski-Oja, J., and Moses, H. L., Proteolytic activation of latent transforming growth factor-beta from fibroblast conditioned medium. J. Cell Biol. 106, 1659-1665 (1988). 

Numerous modifications of in vitro culture systems have been developed for the estimation of BBB transfer [52]. Culture systems in use are either primary cultures of brain microvessel endothelial cells (BMEC) or immortalized endothelial cell hues. BMEC may be grown in co-culture with astrocytes or in astrocyte-conditioned medium. Astrocyte-derived factors increase the tightness of the barrier as measured by transendothelial electrical resistance (TEER) and by the permeability of hydrophUic markers such as sucrose. They also up-regulate the expression of BBB-enriched enzymes such as y-glutamyl transpeptidase (y-GTP) and alkaline phosphatase. A setup of the in vitro technique in a transwell system for transport studies is depicted in Figure 2.5. 

The number of cytokines known to influence hematopoiesis is steadily growing. The most recently identified cytokines are SDF-1 [38], VEGF2 [39] and SCEPF [40],but there are still growth factors in the stromal environment to be identified. This has been proven by the additional growth-supportive effects of stroma-conditioned medium on the proliferation of hematopoietic stem cells. 

Amber, 1. J., Hibbs, J. B., Jr., Parker, C. J., Johnson, B. B., Taintor, R. R., and Vavrin, Z. (1991). Activated macrophage conditioned medium Identification of the soluble factors inducing cytotoxicity and the L-arginine dependent effector mechanism. J. Leukocyte Biol. 49, 610-620. 

Bone marrow cell first time stimulation medium 77% (v/v) DMEM, 15% (v/v) heat inactivated FBS, 5% (v/v) WEHI-3B conditioned medium, penicillin-streptomycin, 1.0 m g/mL ciprofloxacin, 200 mM L-glutamine, 6 ng/mL recombinant murine IL-3 (Peprotech, Cat 213-13), 10 ng/mL recombinant murine IL-6 (Peprotech, Cat 216-lb), and 50-100 ng/mL recombinant murine stem cell factor (SCF Peprotech, Cat 250-03). The total volume is 10 mL for each sample. For the second round stimulating medium, the volume is 4 mL for each sample. 

S. L. Friedman and M. J. P. Arthur, Activation of cultured rat hepatic lipocytes by Kupffer cell conditioned medium. Direct enhancement of matrix synthesis and stimulation of cell proliferation via induction of platelet-derived growth factor receptors, J. Clin. Invest. 84 1780-1785 (1989). 

Cell growth factors may also be produced by a distant cell or tissue and travel to the responding cell via the blood stream (an endocrine response as shown by insulin). These factors are classically known as hormones. Although endocrine factors are present in serum, conditioned medium is frequently a better source of autocrine and paracrine factors. 

Factors such as multiplication stimulatory activity (MSA) are produced by foetal rat liver explants and can be obtained from conditioned medium as follows (Nissley et al., 1979) ... 

Count the cells and distribute into dishes (106 cells/5 cm dish). Macrophages will attach within 30 min and contaminating lymphocytes and fibroblasts may be removed. Peritoneal macrophages do not normally grow in vitro unless conditioned medium is used. A macrophage growth factor is considered in 2.5. 

Calculate the amount of under layer medium required to carry out the experiment and pipet this into a bottle. Add the growth factors to this (usually 10% of the vol of the under layer of each of them if the source is conditioned medium). Return the bottle of medium containing growth factors to the water bath at 37°C. 

The CFU-A colonies derived from murine bone marrow are composed mainly of macrophages (90-95%) when conditioned media are used as sources of growth factors. Using recombinant growth factors (rGFs) increases the percentage of neutrophils in the colonies with a resultant decrease in macrophages. This appears to be linked to the amount of CSF-1 in the conditioned medium or the concentration of rCSF-1 used. 

Colony scattering is probably the easiest assay for detecting factors able to induce cell movement. It was originally described by Stoker and Perryman (1985), to detect a scattering activity for MDCK cells present in fibroblast conditioned medium. 

Burgess, A.W., Camakaris, J. and Metcalf, D. (1977). Purification and properties of colony-stimulating factor from mouse lung-conditioned medium. J. Biol. Chem. 252, 1998-2003. 

END-2 cells secrete mostly unknown cardiac-inducing differentiation factors, and therefore the END-2-conditioned medium can also be used in cardiomyocyte differentiation [100], END-2 cells stimulate differentiation towards mesodermal derivatives. The molecular pathways leading to terminal differentiation of cardio-myocytes are still unclear. 

Mixed leukocyte (or thymocyte) culture-conditioned medium Thymocytes produce lymphokines which stimulate and support growth of B cells (Andersson et al., 1977). These factors may be non-specific (NSF) or specific for the immunogen (Kilburn and Levy, 1980). These NSF represent a heterogeneous group of molecules... 

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