Chitin heparinoid

The molecular weights of chitin heparinoids were estimated from viscosity measurements with a Ubbelohde-type viscometer and using the viscosity equation proposed for heparin [26]. 

Table 2 Effect of Chitin Heparinoids on Experimental Lung Metastasis by Intravenous Injection of B16-BL6 Melanoma Cells ...

Five C57BL/6 mice per group were injected IV with B16-BL6 (5 x 10 ) with or without chitin heparinoids. Mice were killed 2 weeks alter tumor inoculation and lung colonies were measured. 

Five C57BL/6 mice per group were administered chitin heparinoids IV at the indicated times after tumor inoculation. Primary tumors were surgically removed on day 21, and mice were killed 2 weeks after tumor excision. 

Figure 7 Lung retention of [ l]IUdR-labeled tumor cells coinjected with chitin heparinoid into mice. [ IJIUdR-labeled B16-BL6 cells (3 X 10 ) were inoculated with PBS (o) 250 JLg SCM-chitin III ( ) CM-chitin (A) heparin (A) into C57BL/ 6 mice. The radio activity in the lungs was measured at various time intervals after the injection.

Pancreatic ribonuclease is markedly inhibited by heparinoids but not by mucopolysaccharides, with sulphated polyvinyl alcohol >sulphated corn amylosOsulphated cellulose > sulphated corn amylopectin> sulphated dextran, sulphated pectic acid, polyvinyl sulphonate with 2 T 7 per cent sulphur>sulphated nitro chitin, sulphated nitro chitosan and heparin . Single injections of heparin in mice result in significant inhibition of the acid alkaline ribonuclease of the liver after the injection. This probably explains the accumulation of ribonucleic acid in tissue culture cells in the presence of heparin. Heparin also inhibits rat acid phosphatase, glucuronidase , catalase , fumarase and elastase. 

A complete list of semi-synthetic heparinoids is outside the scope of this article. Products of sulfation of neutral polysaccharides include sulfates of starch, cellulose, - - xylan, dextran, " guaran, and synthetic polymers of o-glucose. A somewhat closer simulation of the structure of heparin was attempted by sulfating polysaccharides containing amino sugars or uronic acids or both, such as chitin and chitosan, " and the corresponding N-formyl, N-(car-boxymethyl), O-(carboxymethyl), and 5-carboxylated - deriva-... 

It can be said that chitin is most relevant to our health and welfare, because of the very important interactions between human life and chitin-based life 1. To explain the importance of the knowledge of the chemistry of chitin for the biomedical sciences, we could mention the well-known investigation on structure and function of lysozyme carried out with chitin oligomers lysozyme is present in human body fluids as a defence against chitinous organisms on which it exerts hydrolytic action. A further example is the research on heparin and heparinoids heparin is probably the polysaccharide most closely related to chitin that can be found in the human body, where it reacts specifically with blood components to control blood fluidity and coagulation. 

Selective -sulfation of CM-chitosan was carried out by the method of Whistler and Kosic [8]. In brief, 7.0 g CM-chitosan (degree of carboxy-methylation, 0.60 degree of deacetyiation, about 70%) was dissolved in water and the sulfating reagent (sulfur trioxide-pyridine, 3 Eqmol/NH2) was added dropwise over 3 h at pH 9-10 (adjusted by 4 M NaOH aqueous solution). The reaction mixture was dialyzed against deionized water to remove impurities and then lyophilized yield, 8.1 g. Only a small amount of the free amino group was observed by the ninhydrin test. The O-sulfations of CM-chitin and -sulfated CM-chitosan were successively followed by the use of the SO -dimethylformamide (DMF) system [9]. The chemical and physicochemical properties of heparinoids are listed in Table 1, together with those of A -sulfated chitosan (S-DAC). 

To clarify the mechanism of inhibition of tumor cell invasion by SCM-chitin III, the influence of heparinoids on tumor cell migration through laminin and on the matrix-degrading enzymes (heparanase and type IV col-lagenase) was investigated in tumor cells in vitro. The inhibition of hapto-tactic migration of B16-BL6 cells through laminin-coated filters is shown in... 

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