Heparin liberators

Heparin-liberators. Peptone and specific antigen in the sensitized animal are the most effective liberators of heparin from mast cells. Many histamine liberators also liberate heparin but since many are strongly basic amines, they may combine with and mask the liberated heparin. Commercial heparin may have some action as a heparin-liberator - . 

Proteolytic digestion of proteoglycans liberates the carbohydrate side-chains, which are known as glycosaminoglycans (also known as mucopolysaccharides). All the glycosaminogly-cans contain derivatives of glucosamine or galactosamine. Six major groups are known, one of which is heparin. 

Wolfrom and Rice hydrolyzed heparin in the presence of bromine in order to convert the uronic acids released into aldaric acids.24 The same method, oxidative hydrolysis, was used by Rees and coworkers in order to protect liberated 3,6-anhydrohexose residues. The... 

Some difficulty was experienced in establishing a strict correlation between liberation of amino group and sulfate release. For example, Wolfrom and McNeely, and Jorpes, Bostrom and Mutt, did not obtain correspondence between these when heparin was treated with hot, dilute acid. It was suggested that retention of the barium sulfate in the colloidal state (peptization) by the heparin might be responsible for inaccurate results in sulfate analysis. If, however, heparin was first treated with hot, dilute alkali, then, on subsequent acid treatment, correspondence between release... 

Berglund showed that sulfamic acid derivatives are relatively stable under alkaline conditions which cause hydrolysis of A-acetamido groups. Jorpes, Bostrom and Mannson, utilizing these data, found that less than 10% of the total amino groups is liberated when a 0.2% solution of heparin in N sodium hydroxide is heated at 100° for 2 hours, whereas 55 % of that in chondroitinsulfate is released. 

Mast cells may disrupt (clasmatosis) and release their granules into the ground substance, liberating heparin and other chondroitin sulfates. Thus, the mast cell may be a storage form of the fibroblast. This release of granules is similar to secretion of many substances by other cells and would be a merocrine type of secretory activity. 

To see whether heparin would be of help in infectious liberation of histamine, 10 cases of laryngotracheal bronchitis severe enough to require tracheotomy were also treated with 100-200 mg of heparin administered intravenously. Six of the children were boys and 4 were girls. They ranged in age from 1 to 9 years. All of them responded to heparin early. Tracheotomy was avoided in nine of the cases. The tenth patient developed a temper tantrum 18 hours after relief of symptoms and severe cyanosis appeared to develop. It was believed that if heparin did not produce relief immediately, there would not be time for surgery hence, an emergency tracheotomy was performed. 

Liberators of antithrombin and/or heparin cofactor. The latter proteins appear to be secreted by the liver, and result in hypocoagulability in thrombin titration tests and increase the sensitivity of the coagulation time and other tests to heparin. Papain releases antithrombin. ... 

The nature of the actual interaction cannot be established from con-ductimetry alone. In a discussion of the reaction between heparin and poly cations, Rembaum and Haack noted the associated liberation of sodium chloride, and inferred that changes in chain conformations must occur during the reaction. They suggest that the mechanism of the reaction involves an isoelectric jump, on which there has been a considerable amount of experimental and theoretical work, in order to elucidate the reaction thermodynamics. A similar mechanism may well be operative in the heparin-aminoglycoside interactions. 

The tests carried out for the evaluation of the blood anticoagulant activity of sulfated N-carboxymethyl chitosan are the same as those for the determination of heparin, i.e. the antithrombin test for the thrombin inhibition and the heparin test for the factor Xa inhibition. Both of these tests were done by spectrophotometry at 405 nm on the p-nitroaniline liberated from a chromo-genic substrate. 

The clinical symptoms are caused by the liberation of the pharmacologically active substances contained in the mastocytes (i.e. primarily histamine and heparin). A considerable in-... 

An enzyme with properties resembling those of the heparin-clearing factor lipase has been found in extracts of heart, adipose and other tissues (Korn 1955a Korn and Quigley 1957 Iselin and Schuler 1957). Perfusion of heparin through the circulation of many organs causes the liberation of clearing factor into the perfusate (Jeffries 1954 Robinson and Harris 1959 Swank and Levy 1952) while no activity is released from liver or brain. 

Chebkes, a., and R. S. Gobdon jr. The liberation of lipoprotein lipase by heparin from adipose tissue incubated in vitro. J. Lipid. Res. 1, 97 (1959). 

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