Human activity, viii

PCCs contain the vitamin K-dependent factors II, VII, IX, and X. These agents represent another attempt to bypass the factor at which the antibody is directed (see Fig. 64-2). However, PCCs carry the risk of serious thrombotic complications. Porcine factor VIII is most useful when the inhibitor titer is less than 50 BU (see Fig. 64-2 for dose and frequency). Owing to its similarity to human factor VIII, porcine factor VIII participates in the coagulation cascade. However, most inhibitors have very weak neutralizing activity against it. Porcine factor VIII is a third-line agent (only after factor Vila and a PCC have failed) owing to a 15% incidence of cross-reactivity.15... 

Along with the production of insulin, many other medical uses have been achieved for recombinant DNA. This includes the production of erythropoetin, a hormone used to stimulate production of red blood cells in anemic people tissue plasminogen activator, an enzyme that dissolves blood clots in heart attack victims and antihemophilic human factor VIII, used to prevent and control bleeding for hemophiliacs. These three important genetically engineered proteins were all cloned in hamster cell cultures. 

Balague, C., Zhou, J., Dai, Y., Alemany, R., Josephs, S. F., Andreason, G., Hariharan, M., Sethi, E., Prokopenko, E., Jan, H. Y., Lou, Y. C., Hubert-Leslie, D., Ruiz, L. and Zhang, W. W. (2000). Sustained high-level expression of full-length human factor VIII and restoration of clotting activity in hemophilic mice using a minimal adenovirus vector. Blood 95, 820-828. 

Chemical standards are widely used to protect the environment and human health from substances released by human activity. Generally, standards relate to doses or concentrations in the environment for specific chemicals, below which unacceptable effects are not expected to occur. Many standards are legally enforceable numerical limits, such as Environmental Quality Standards for List 1 chemicals in water or Annex X and VIII standards under the European Water Framework Directive. Others are not mandatory but are contained in guidelines, codes of practice, or sets of criteria for deciding individual cases. Some standards are not set by governments but carry authority for other reasons, especially the scientific eminence or market power of those who set them (e.g., World Health Organization guidelines). 

Nesheim, M., Pittman, D. D.,Giles, A Pass, D, N Wang,). H.,Slonosky D., and Kaufman, R. J. fl99l. The effect of plasma von Willebrand factor on the binding of human factor VIII to thrombin-activated human platelets. Biol. Ciicm. 266,17815-17820. 

Fll. Fulcher, C. A., Gardiner, J. ., GrifBn, J. H., and Zimmerman, T. S., Proteolytic inactivation of human Factor VIII procoagulant protein by activated human protein C and its analogy with Factor V. Blood 63, 486-489 (1984). 

Human factor VIII Antibody to factor VIII CNBr-activated Sepharose 4B 221... 

Antihemophilic factor, Factor VIII, a protein (Mr 265 kDa) acting as component of the blood clotting cascade in humans. Activated Factor VIIT acts as an accessory factor during the activation of Factor X Stuart factor) by activated Christmas factor IXa. Factor VIII forms a complex with the Willebrandt factor during circulation in blood [T. Halkier, Mechanisms in Blood Coagulation, Fibrinolysis and the Complement System, Cambridge University Press, 1991]. 

The complete 7 kb protein-coding sequence of human factor VIII was assembled from portions of overlapping cDNA and genomic clones and Introduced into appropriate mammalian expression vectors (9,10). Following transformation into either hamster kidney cells (9) or COS-1 monkey cells (11) factor VIII expression in transfected cell lines was characterized. The recombinant protein was shown to be biologically active, demonstrating the ability to activate factor IX and to reduce clotting time in plasma derived from patients affected with hemophilia A. Additionally, factor VIII activity of transfected cells was inhibited by a factor Vlll-specific antibody. 

Purified and reduced human Factor VIII exhibits an eight band sub-unit structure (mol. wt. 3.0 X 10 —2.3 x 10 ) as shown by polyacrylamide gel electrophoresis. Rabbit antibody to Factor VIII reacts with all of the sub-units whereas haemophilic antibody reacts with low-molecular-weight sub-units only. Sub-units derived from the largest Factor VIII multimers have a higher binding affinity for D-galactose-specific lectins than have those obtained after reduction of smaller oligomers. Ristocetin cofactor activity of purified Factor VIII is competitively inhibited by two Ricinus communis lectins and by concanavalin A. 

Y. Kurono, T. Furukawa, T. Tsuji, K. Ikeda, Esterase-Like Activity of Human Serum Albumin. VI. Reaction with p-Nitrophenyl Glycinate , Chem. Pharm. Bull. 1988, 36, 4068-4074 Y. Kurono, I. Kushida, H. Tanaka, K. Ikeda, Esterase-Like Activity of Human Serum Albumin. VIII. Reaction with Amino Acid p-Nitrophenyl Esters , Chem. Pharm. Bull. 1992, 40, 2169-2172. 

Y. Kurono, I. Kushida, H. Tanaka, K. Ikeda, Esterase-Like Activity of Human Serum Albumin. VIII. Reaction with Amino Acid p-Nitrophenyl Esters , Chem. Pharm. Bull. 1992, 40, 2169-2172. 

Two examples where metal ions confer stability or increased activity in proteins are human deoxyribonuclease (rhDNase, Pulmozyme ), and Factor VIII. In the case of rhDNase, Ca2+ ions (up to 100 mM) increased the stability of the enzyme through a specific binding site (64). In fact, the removal of calcium ions from the solution with EGTA caused an increase in deamidation and aggregation. However, this effect was observed only with Ca+2 ions other divalent cations, Mg2+, Mn2+, and Zn2+, were observed to destabilize rhDNase. Similar effects were observed in Factor VIII. Ca2+ and Sr2+ ions stabilized the protein, whereas others such as Mg2+, Mn2+ and Zn2+, Cu2+, and Fe2+ destabilized the enzyme (65). In a separate study with Factor VIII, a significant increase in the aggregation rate was observed in the presence of Al3+ ions (66). The authors note that other excipients like buffer salts are often contaminated with Al3+ ions and illustrate the need to use excipients of appropriate quality in formulated products. 

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