Serum factors

Ross, R, Glomset, J. and Kariya, B. (1974). A platelet-dependent serum factor that stimulates the proliferation of smooth muscle cells. Proc. Natl Acad. Sci. USA 71, 1207-1210. 

There is a long-standing hypothesis that the microvasculature plays a pathological role in forms of chronic inflammatory polyarthritis, particularly RA (Rothschild and Masi, 1982). One of the proposed mechanisms of vascular damage in connective tissue disease is the direct action of a cytotoxic serum factor inducing endothelial cell damage. Blake et al. (1985) have su ested that the vascular abnormalities associated with RA may be linked to oxidized lipoproteins because they are cytotoxic to endothelial cells. 

In addition, HIV-1 infection also induces the secretion of certain metallo-proteinases (MMP-2, MMP-9) that are capable of cleaving the N-terminus of SDF-1 but not that of the P-chemokines, and this decreases SDF-1 affinity for CXCR4 binding (227-229). Proteolytic modification of SDF-1 by a serum factor(s) that is different from CD26 and MMPs, which results in reduced anti-HIV activity, has been described as well (230). How SDF-1 proteolytic... 

Figure 1.15. Complement activation via the alternative pathway. Always present in serum are trace amounts of C3b, which may attach to recognition sites on, for example, yeast cell walls. C3b may combine with serum factor B to form C3bB, and this complex is acted upon by factor D to form C3bBb. This latter complex is a C3 convertase and may act upon C3 to form more C3b to amplify the process. The C3bBb-coated particles may activate other complement components (C4-C9) or be recognised by complement receptors on neutrophils.

Masui T, Wakefield LM, Lechner JF, LaVeck MA, Spom MB, Harris CC (1986) Type beta transforming growth factor is the primary differentiation-inducing serum factor for normal human bronchial epithelial cells. Proc Natl Acad Sci USA 83(8) 2438-2442. 

Imbra RJ. Karin M (1987) Metallothionein gene eiqjression is regulated by serum factors and activators of protein kinase C. Mol Cell Biol 7 1358-1363... 

Revisit the need for rat serum as the culmre medium. Characterize rat serum using modern proteomic techniques (e.g., MALDT mass spectrometry) to identify serum factors essential to normal in vitro embryonic growth and development. 

Egelrud and Olivecrona (1973) studied the catalytic activity against several substrates of bovine milk enzyme preparations that had been purified about 7000-fold to a purity higher than 80% (Egelrud and Olivecrona 1972). The enzyme catalyzed the hydrolysis of emulsified trioleate, trioctanoate, monooleate, Tween 20 (polyoxyethylene sorbitan monolaurate), and p-nitrophenyl acetate. It was concluded that the enzyme had rather low substrate specificity and that the presence of activating serum factors is not needed for catalysis to occur. 

Egelrud, T. and Olivecrona, T. 1973. Purified bovine milk (lipoprotein) lipase Activity against lipid substrates in the absence of exogenous serum factors. Biochem. Bio-phys. Acta 306, 115-127. 

The history of the development of antitoxins in combating bacterial infection dates back to the early beginnings of organized bacteriology. Belrring was tile first to show that animals that were immune to diphtheria contained, in their serum, factors which were capable of neutralizing the poisonous effect of the toxins derived from the diphtheria bacillus. While this work was earned out in 1890, prior to many of the great discoveries of mass immunization, and much later the antibiotics, there yet remains a place for antitoxins in medical treatment or prophylaxis for some diseases, such as tetanus and botulism,... 

The first discovery of serum factor in human lupus with affinity for tissue nuclei was from three laboratories almost simultaneously in 1957 (H14, Cl, Rll). 

Svensson, B. O., Serum factors causing impaired macrophage function in systemic lupus erythematosus. Scand. J. Immunol. 4, 145-150 (1975). 

Tomida, M., Koyama, H., and Ono, T., A serum factor capable of stimulating hyaluronic acid synthesis in cultured rat fibroblasts, J. Cell Physiol., 91, 323, 1976. 

It was observed that CHO cells which had entered a stationary phase in Ham s F10 medium could be stimulated to undergo a further round of division by changing the medium. The growth limitation was not a serum factor but was traced to a deficiency in isoleucine which is present in Ham s F10 medium at only about 5-10% its concentration in other media (Ley and Tobey, 1970 Tobey and Ley, 1970). 

C) Infect cells and plate out at a low density in low serum medium. Many cells may divide once or twice (abortive infection) but the stably transformed cells will form colonies in the absence of serum factors (Smith et al., 1970). 

Whilst these observations point to a potentially important cell-regulatory role for HNE, little is known about factors that control the rate of its production. Clearly a prerequisite is the formation of cellular lipid hydroperoxides, but although levels of those can apparently be modulated by serum factors there is a need to explore mechanisms, possibly enzymatic, whereby HNE levels might be tightly regulated. In this context it is known that HNE can serve as a substrate for glutathione transferase [64], or aldehyde dehydrogenase [66] ... 

Garswell, E. A., Old, L. J., Kassel, R. L., Green, S., Fiore, N., and Williamson, B. (1975). An endotoxin-induced serum factor that causes necrosis of tumors. Proc. Natl. Acad. Sci. USA 72, 3666-3670. 

Consideration may have to be given to using a supplemented medium during the initial stages of culture to aid cell attachment and to offset the effects of low cell density, which will be more critical in microcarrier than stationary culture. The supplementation may be simple, e.g. non-essential amino acids, pyruvate (0.1 mg mH), adenine (10 jxg mH), hypoxanthine (3 xg ml" ) and thymidine (10 xg mH). Other supplements include tryptose phosphate broth (1 mg mH), HEPES (5 mM), transferrin (10 mg T ) and fibronectin (2 xg mH). Serum, unless serum factors are added, may have to be used at 5-10% initially before being reduced after 1-2 days of culture. 

Masui, T., Wakefield, L.M., Lechner, J.F., LaVeck, M.A., Sporn, M.B. and Harris, C.C. (1986). Type jS transforming growth fector is the primary dififerentiation-inducing serum factor for normal human bronchial epithelial cells. Proc. Natl. Acad. Sci. USA 83, 2438-2442. 

Utter, F.M. and G.J. Ridgeway. A serologically detected serum factor associated with maturity in the English sole, Parophrys vetulus and Pacific halibut, Hippoglossus stenolepis. US Fish Wildl. Serv. Fish. Bull. 66 47-48, 1967. 

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