Blood substitute, dextran

Dextrans are particularly useful and are employed as a plasma substitute. A concentration of about 6% dextran (50,000-100,000 relative molecular weight) has equivalent viscosity and colloid-osmotic properties to blood plasma. Dextran can also be used as non-irritant absorbent wound dressings, an application also suited to alginate gels. 

The direct histamine release evoked by several substances (e.g. codeine, dextran in certain rat strains or gelatine blood substitutes) led to the development of the concept of pseudo-allergic reactions by Paul Kallos [10]. 

An extreme example of slime production is found in Leuconostoc dextranicum and L. mesenteroides where so much carbohydrate, called dextran, may be produced that the whole medium in which these cells are growing becomes almost gel-like. This phenomenon has caused pipe blockage in sugar refineries and is deliberately encouraged for the production of dextran as a blood substitute (Chapter 25). 

Dextran -hemoglobin -as blood substitute [BLOOD, ARTIFICIAL] (Vol 4)... 

Dextran Frozen sugar beet Chromatographic sorbent (Sephadex) blood substitute... 

Dextran is a polyglucose biopolymer characterized by preponderance of a-1,6 linkage, and generally produced by enzymes from certain strains of Leuconostoc or Streptococcus. While formerly its principal utility was as a blood plasma substitute, dextran is also used in various fields such as pharmaceutical, photographic,... 

Alexander B (1978) Effects of plasma expanders on coagulation and hemostasis dextran, hydroxyethylstarch, and other macromolecules revisited. In Blood substitutes and plasma expanders. Liss, New York, pp 293-326 Alexander CS, Zievel L (1961) Fat infusion. Arch Intern Med 107 514-528 Allardyce DB (1982) Cholestasis caused by lipid emulsions. Surg Gynecol Obstet 154 641-647... 

Thoren L (1978) Dextran as a plasma volume substitute. In Blood substitutes and plasma expanders. Liss, New York, pp 265-282... 

Dextran is used mostly in medicine as a blood substitute. In the food industry it is used as a thickening and stabilizing agent, as exemplified by its use in baking products, confections, beverages and in the production of ice creams. 

Because of the potential of Dextran polymers as blood substitutes, the oxygen affinity of hemoglobin coupled by the polymers are extensively studied. Reduced oxygen affinity of hemoglobin by Dextran polymers was reported by Nguyen [7] and Sacco [1]. Recently, Dubin et al. [44] found that the ligandbinding cooperativity of hemoglobin is affected by the complexation with PDMDAAC. 

Leuconostoc mesenteroides dextrans have acquired considerable importance during recent years following the discovery that, when suitably degraded, they can be used as a substitute for blood plasma. Dextran sulphate is also used as a blood anticoagulant. Other ethers and esters of dextran find widespread applications in industry. 

This method is universal for different polymers, and it can be used for MMD analysis of blood substitutes based on dextran instead of requiring a lengthy and complicated procedure recommended by EP. 

The validation results allow recommending including MALLS detector method for the MMD determination of blood substitutes based on HES and dextran in Russian Pharmacopoeia. 

Wong, J.T. RlghtshUted dextran-hemoglobln as blood substitute. Biomater Artif Cells Artif Organs 16 237-245,1988. 

A number of other polysaccharides, such as glycogen, dextran, chitin, etc., possess interesting structures for chemical modification [103,104]. Dextran has been used as a blood plasma substitute. Although it can be converted to films and fibers, chitin s relatively small resource restricts its commercialization. 

The IV solutions of plasma expanders include hetastarch (Hespan), low-molecular-weight dextran (Dextran 40), and high-molecular-weight dextran (Dextran 70, Dextran 75). Plasma expanders are used to expand plasma volume when shock is caused by bums, hemorrhage surgery, and otiier trauma and for prophylaxis of venous thrombosis and diromboembolism. When used in die treatment of shock, plasma expanders are not a substitute for whole blood or plasma, but tiiey are of value as emergency measures until die latter substances can be used. 

Other important examples are blood and blood products, which are collected and processed in sterile containers, and plasma substitutes, for example dextrans and degraded gelatin. Dextrans, glucose polymers consisting essentially of (1 - 6) a-links, are produced as a result of the biochemical activities of certain bacteria of the genus Leuconostoc, e.g. L. mesenteroides (see Chapter 25). 

Dextrans are produced commercially for use as plasma substitutes (plasma expanders) which can be administered by intravenous injection to maintain or restore the blood volume. They can be used in applications to ulcers or bum wounds where they form a hydrophilic layer which absorbs fluid exudates. 

Claims have recently been made61 that the dextran of L. mesenteroides may serve as an efficient substitute for blood plasma. Solutions of partially-hydrolyzed dextran in saline gave favorable results when injected intravenously into experimental animals. Preliminary clinical tests were promising. 

In addition to murein, bacterial polysaccharides include dextrans—glucose polymers that are mostly al 6-linked and al 3-branched. In water, dextrans form viscous slimes or gels that are used for chromatographic separation of macromolecules after chemical treatment (see p.78). Dextrans are also used as components of blood plasma substitutes (plasma expanders) and foodstuffs. 

On the positive side, dextran itself has been refined and employed as a therapeutic agent in restoring blood volume for mass casualties. Natural dextrans have very high molecular weight (on the order of 10 -10 Da) and are found to be unsuitable as a blood-plasma substitute. Lower molecular weight (about 10 Da) dextran is suitable and often referred to as clinical dextran. 

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