Heparin stability

KA Jandik, D Kruep, M Cartier, RJ Linhardt. Accelerated heparin stability studies. J Pharm Sci 85 45-51, 1996. 

Schwartz, L.B. and Bradford, T.R. (1986). Regulation of tryptase from human lung mast cells by heparin. Stabilization of the active tetramer. J. Biol. Chem. 261, 7372-7379. 

Carbonic 28 days with heparin stabilizer Adsorption, aggregation, and denaturation (24,25)... 

Most blood for Pb determination is collected by venipuncture. Polyvinylchloride (PVC) disposable syringes may add minute amounts of lead up to 0.01-0.05 p.mol/liter to the true content [55]. Skin puncture (fingertip, or earlobe) has also been used. However, severe contamination problems have been reported thus skin-cleaning procedures are necessary [12]. EDTA-stabilized whole blood is conveniently stored in polyethylene or polypropylene containers at-20°C for several years [15]. However, it should be noted that this anticoagulant is a matrix modifier in AAS determinations and contains trace elements. Hence it is recommended that EDTA is checked regularly for contamination. Heparin-stabilized blood appears to become unstable after several years of storage [15,56]. 

To cite a few examples, anticoagulants must nearly always be added to the blood sample. There are various anticoagulants, for example, heparin, citrates, or EDTA. Best quality of RNA and DNA samples may be obtained from citrate-stabilized blood, but it may lead to a higher yield of lymphocytes for culture. On the contrary, heparin-stabilized blood could influence T-cell proliferation, and moreover heparin binds to many proteins and may therefore compromise proteomic studies. EDTA is suitable for both DNA assays and proteomics, but it affects Mg" " concentration causing problems for cytogenetic analyses (e.g., decreases mitotic index). 

In viw PAI and antithrombin are stabilized in their active forms by binding to vitronectin and heparin, respectively. These two serpins seem to have evolved what Max Perutz has called "a spring-loaded safety catch" mechanism that makes them revert to their latent, stable, inactive form unless the catch is kept in a loaded position by another molecule. Only when the safety catch is in the loaded position is the flexible loop of these serpins exposed and ready for action otherwise it snaps back and is buried inside the protein. This remarkable biological control mechanism is achieved by the flexibility that is inherent in protein structures. 

Heparin sulfate proteoglycans (HSPGs) are heavily glycosylated proteins that are part of the extracellular matrix. Interaction with HSPGs help to stabilize and localize extracellular Wnts. 

Sample Collection and Enzyme Stability. Serum samples are collected with chemically clean, sterile glassware. Blood is allowed to clot at room temperature, the clot is gently separated from the test tube with an applicator stick, and the blood is centrifuged for 10 minutes at 1,000 g. If the red cells are known to contain the enzymes whose activity is being measured, as in the case of LD, even slightly hemolyzed serums must be discarded. When acid phosphatase is to be measured, the serum should be placed immediately in ice and processed as soon as possible, or it should be acidified by the addition of a small amount of sodium citrate. Anticoagulants such as EDTA, fluoride and oxalate inhibit some serum enzymes. However, heparin activates serum lipoprotein lipase. 

The benefit and necessity of adding heparin to PN are unclear. There are also concerns about the stability/compatibility of intravenous lipid emulsions with heparin added at concentrations above 1 unit/mL. Heparin should be omitted in patients with active bleeding, thrombocytopenia, heparin-induced thrombocytopenia (HIT), or heparin allergy. 

Sucrose octasulfate (23, Structures 6) bound to FGF and was able to induce, like heparin, a conformational change in the peptide, but showed very low mitogenic activity for an F32 cell line. The basic aluminium salt of sucrose octasulfate, which is used as a drug (Sucralfate, Carafate) for the treatment of duodenal ulcers was claimed to exert part of its activity through the stabilization of FGF... 

Recombinant human keratinocyte growth factor Heparin (0.5% w/v) Solution -50 fold increased stability at 37°C [21]... 

Heparin and heparin-like polyanions are known to have significant stabilizing effects on proteins. Heparin itself has been used as a constituent of the solution used to reconstitute lyophilized proteins (54) while enoxaparin is a low molecular weight... 

Stability. Some discussion regarding stability of milk lipases was presented in the preceding section. Egelrud and Olivecrona (1973) found that the enzyme fractions from heparin-Sepharose can be stored frozen at -20°C with less than 10% loss of activity in 2 weeks. The purified enzyme had only moderate stability at 4°C high concentrations of salt or a pH below 6.5 or above 8.5 increases the rate of inactivation. 

Table 1 demonstrates that high lytic activity is displayed by the complexes of thrombin and fibrinogen as well as by that of heparin and plasmin. These complexes, as was shown in Ref.35), affect the unstabilized fibrin only and supress simultaneously the activity of the fibrin-stabilizing factor. Qualitatively similar results were observed in in vivo experiments. 

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