Uses of heparin as an anticoagulant

This means the clinical use for treatment of thrombosis (in 25 patients) during this period was only 20 per cent of the total used, and 80 per cent was used in patients as an anticoagulant adjunct to diagnosis, irrigation or surgical repair. 

Purified heparin is used as a substitute for oxalate and citrate. The amounts of common anticoagulants required to prevent coagulation effectively in vitro in mg/ml. are potassium oxalate, 0-5 sodium and ammonium oxalates, 

0-5 lithium oxalate, 0-3 Heller and Paul mixture, 0-5 sodium citrate, 

Heparin is well known for its usefulness in the pharmacology laboratory in many animal experiments for preventing clotting during recording of blood pressure. The many manifold effects of heparin on hormones, cell permeability, activation of various enzymes, and uptake of P by brain tissue, must be controlled in animal experiments when heparin is used as an anticoagulant. 

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Interactions of heparinoids with the most diverse proteins such as enzymes and enzyme inhibitors, cytokines, and adhesion molecules have been described. To date, many more than a hundred heparin binding proteins are known. A number of heparin binding proteins are members of the serpin family of serine protease inhibitors. The best described example is antithrombin [4]. Antithrombin III (AT III) is able to inhibit various serine proteases involved in the blood coagulation process by formation of stable, equimolar complexes. Binding of heparin to AT III accelerates the kinetics of this complex formation by several orders of magnitude. This has been the basis for the successful clinical use of heparin as an anticoagulant for nearly sixty years. 

The author is indebted to Miss Sylvia Hoffer of the Pharmaey Department, University Hospital, Saskatoon for collecting the data on Uses of Heparin as an Anticoagulant (p. 164). 

Despite its widespread use in therapy as an anticoagulant and antilipe-mic agent, several aspects of the structure and physiological function of heparin remain obscure. However, active reseach has now contributed to a better understanding of the molecular basis for the pharmacological activity of this polysaccharide. 

Heparin is clearly an extraordinarily complex substance with many highly polar groups, and its mode of action as an anticoagulant is not clear. At present, because of increases in the use of artificial kidney machines, heparin is in rather short supply. 

The inadvertent use of lithium heparin as an anticoagulant in the collection tube will lead to a spuriously high serum lithium determination. 

The choice of container for samples is important, since contamination from rubber, cork, and colored plastics can be a problem. For blood plasma, collection plastic tubes with lithium heparin as an anticoagulant are suitable for most analyses. For blood serum, plain glass containers can be used. For the uitratrace metals (Mn, Cr), special arrangements have to be made to collect blood via plastic cannulae or silanized steel needles, and then the sample is placed into acid-washed containers. Trace metal vacutainers are avahabie commercially. It is good practice to run dilute acid blanks through all the containers and collection systems to ensure that all batches remain as free from contamination as possible. 

Serum or plasma (with heparin as an anticoagulant) can be used. No special handling procedures are necessary, and specimens may be stored refrigerated overnight at 2 °C to 8 °C. Freezing is preferred for long-term stability. Urinary free cortisol is determined on a 24-hour urine collection with or without boric acid preservative. If collected without preservative, the specimen should be refrigerated between collections and an aliquot frozen immediately after completion of the 24-hour collection. 

Briem et al. [33] also describe the use of a liquid handler to perform the sample preparation steps in an automated manner. The sample preparation consisted in taking a 25 pL aliquot of the plasma sample and adding 150 pL of acetonitrile (ACN) containing the internal standard (IS) and then following typical protein precipitation (PPT) procedure steps. The authors noted that the 1 6 ratio of plasma to ACN worked well for the liquid handler and exceeded the 1 3 criterion reported by Poison et al. [34] as the minimum ratio of plasma to ACN needed to remove at least 96% of the proteins from the plasma sample. The authors also noted that use of EDTA (instead of heparin) as the anticoagulant helped to avoid clots in plasma as has been reported previously by other authors [35-37], The authors also stated that the robotic method... 

Gervin, C.A., Gervin, A.S., Nichols, W. and Corrigan, J.J. (1983) Problems in the measurement of zinc using heparin as an anticoagulant. Life Sciences, 33, 2643. 

Hematologic Numerous papers on heparin-induced thrombocytopenia continue to appear, including a systematic review of the use of argatroban as an alternative anticoagulant [16 ]. Two prospective, multicenter, non-randomized, open studies of the use of argatroban... 

Heparin, as an anticoagulant, displays a potent inhibitory effect on PCR, affecting both Taq Pol and DNA (13). Note that heparin is used in enzymology as an efficient trap for free DNA polymerases. DNA samples from the blood long stored in heparinized tubes have often been found to be unsuitable for PCR amplification, even after removal of the heparin. EDTA or citrate can be used as the substitute anticoagulant to store the whole blood with no deleterious effects on DNA. 

Post laser atherectomy and percutaneous transluminal angioplasty of popliteal artery as well as tibioperoneal trunk, IV heparin used as an anticoagulant with pretreatment with aspirin and clopidogreh... 

PRP and PPP preparation. If rats or mice are used, they are anaesthetized by an i.p. injection of sodium pentobarbital (50 mg/Kg), and blood is drawn into heparin (5 units/ml final) or citrate/dextrose (final concentration 0.38% and 0.48% (wt/vol), respectively) anticoagulant from the dorsal aorta or by heart puncture, with a 22-gauge needle (the choice of heparin as anticoagulant appears to be more appropriate, because chelation of divalent cations by trisodium citrate or EDTA might affect platelet-tumor cell interaction). Blood is then diluted with an equal volume of 0.9% NaCl, and centrifuged for 7 min at 400 x g on preformed gradients of 70% Percoll containing 0.9% NaCl. The yellowish supernatant is the PPP, while PRP forms a white band between PPP and the percoll layer. Platelets in PRP are counted with a Coulter counter and diluted with PPP to a concentration of 10 /ml. PPP is a source of prothrombin, and should thus be included in the assay. 

Comments (S42, S75).- Sera of plasmacytoma patients and newborn show differences of over 100% compared to the wet chemistry method. Due to their high viscosity, these samples must be diluted in a ratio of 1 15. If water or common salt solution are used as solvents, bilirubin concentrations occur that are 1 to 3 times higher. It is therefore recommended to dilute with a serum having a very low bilirubin concentration. This method, however, is very questionable and should therefore be rejected. Heparin is mentioned as an anticoagulant EDTA is unsuitable for plasma separation. 

Heparin is used as an anticoagulant for prophylaxis and treatment of various thromboembolic disease processes. It is used to maintain relatively anticoagulated states in patients on extracorporeal circulation or hemodialysis and to help maintain patency of indwelling vascular catheters. 

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