Umbilical cord, hyaluronic acid from

Hyaluronic acid. From a water extract of human umbilical cords hyaluronic acid was purified by the metnod originally reported for bovine synovial fluid ( ). The preparation was practically free of protein and sulfated glycosaminoglycans. 

Hyaluronic acid (from vitreous humor, umbilical cord, synovial fluid, ovarian tumor, Group A hemolytic streptococcus and skin)... 

The infrared absorption spectra of hyaluronic acids from different sources are essentially similar. " Identical infrared absorption spectra are given by hyaluronate from Rous sarcomas and from umbilical cords. Shght quantitative differences between the spectra of hyaluronic acid from umbilical cord and of those from both myxoedemal " and streptococcal hyaluronate may be due to impurities. 

Meyer K, Palmer JW, Smyth EM. Glycoproteins. II. The polysaccharides of vitreous humor and of umbilical cord. J Biol Chem 1936 114 689-703. Weissman B, Meyer K. The structure of hyalobiuronic acid and of hyaluronic acid from umbilical cord. J Am Chem Soc 1954 76 1753-1757. 

Hyaluronan was identified by Karl Meyer11 in 1938 as a hexuronic acid-containing material that also provided the turgor for the vitreous of the eye. The name hyaluronic acid was proposed from the Greek hyalos (glassy, vitreous) and uronic acid. It required 20 years however before the chemical structure of HA was established.12 It was later found to be a present in virtually every vertebrate tissue, the highest concentrations occurring in the vitreous of the eye, in the synovial fluid in the joint capsule, and in the umbilical cord as Wharton s jelly. However, over 50% of total body HA is present in skin.13... 

Chondroitin 4- and 6-sulfates were originally designated as chondroitin sulfate A and C, respectively, and the close similarity in structure between them is demonstrated by the fact that both mucopolysaccharides yield the same disaccharide (chondrosine) on controlled, acidic hydrolysis together with sulfuric and acetic acids. Chondroitin 4-sulfate or chondroitin 6-sulfate, or both, occur in cartilage and adult bone, and the former mucopolysaccharide is a minor constituent of ligamentum nuchae and cornea (M17). Chondroitin 6-sulfate is a minor constituent of umbilical cord and occurs with dermatan sulfate (chondroitin sulfate B) and hyaluronic acid in heart valves and adult connective tissue (M17). An acid mucopolysaccharide isolated from human plasma resembles chondroitin 4-sulfate in its properties (S4). 

Hyaluronic acid was first isolated by Karl Meyer from vitreous humor (30) and later from umbilical cord, synovial fluid, skin, cock s comb, certain fowl tumors, groups A and C hemolytic streptococci, and other sources 31). Historically, it has been a major and frequent if not universal component of Levene s so-called mucoitin sulfates. The polysaccharide acts in animal tissue presumably as an integral part of the gel-like ground substance of connective tissue (and other tissues). Another important function of hyaluronic acid in animals is serving as a lubricant and shock ab-sorbant in the joints. 

Hyaluronic acid is generally prepared from umbilical cords. Most of the protein is removed by digestion with pepsin and trypsin, and the residual protein is separated by the chloroform - amyl alcohol procedure. Hyaluronic acid may be precipitated by fractionation with ammonium sulfate in the presence of pyridine (32). This step also removes a contaminating polysaccharide sulfate. 

Similarly, the protein of funis (umbilical cord) mucin was precipitated by formaldehyde at pH 7, and the hyaluronic acid remained in solution. Other known sulfate esters (limacoitin sulfate and heparin) dissociated from the mucoproteins under similar conditions (4). 

Over the next 10 years, Meyer and other authors isolated hyaluronan from various animal organs. For example, the polysaccharide was found in joint fluid, the umbilical cord and recently it has become possible to extract HA from almost all vertebrate tissues. In 1937, F. Kendall isolated hyaluronan from the capsules of streptococci groups A and C. This work had great scientific and practical importance, as today streptococci groups are the most economical and reliable source for the industrial production of hyaluronic acid [3]. 

Preparation from Umbilical Cord. Human cords are usually collected under acetone. Dried cords contain between 6 and 8% of hyaluronic acid (58). A number of preparations, especially the older ones, have been obtained by solvent purification (10). K. H. Meyer et al. (135) isolated hyaluronic acid by several alcohol fractionations, Sevag treatments, dialysis, and electrodialysis. Electrophoretic analysis showed that the final product contained 70% hyaluronic acid, 19% chondroitin sulfuric acid, and 11% of a third component. A similar study of a carefully prepared hyaluronate has been presented by Kay and Stacey (94). 

Several methods allow the preparation of purified hyaluronate from umbilical cords in a matter of a day or two (88,188). The procedure of Jensen (88) is a model of simplicity. Minced, alcohol-dried cords are washed with 90% acetic acid, and extracted with water at pH 7. Potassium hyaluronate is obtained from the extract by two successive alcohol precipitations according to McClean. Preparations of high viscosity are obtained in good yields (89). 

Fig. 9 Migration of hematopoietic stem cells isolated from umbilical cord blood on various collagen samples. Concentration was 1.2mg/ml for collagen and 0.4mg/ml for heparin and hyaluronic acid, respectively...

The molecule is probably not branched, or only slightly so. The molecular weight is very great (several million). Hyaluronic acid is a principal component of the ground substance of connective tissue. It is found, among other places, in the synovial fluid, in the vitreous humor of the eye, and in skin, usually in combination with protein. Frequently it is prepared from umbilical cord. 

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