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Results for “Hyaluronic Acid”

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At least 19 recordsLinked to original sources
PubMedDate not supplied

Sulfhydryl-dependent thermal aggregation of human gamma globulin: augmentation by hyaluronic acid.

Hyaluronic acid (4 mg/ml) augmented elevenfold the copper-catalyzed (7 muM) thermal (63 degrees C, 2 hours) aggregation of human gamma globulin (2 mg/ml) in 0.075 M phosphate buffer, pH 7.4. Almost no augmentation of aggregation occurred with hyaluronidase-treated hyaluronate. Hyaluronate-augmented copper-catalyzed thermal aggregation was inhibited by L-histidine, gold thiomalate, N-ethylmaleimide, p-chloromercuribenzoic acid, and ethylenediaminetetraacetic acid. Together with previous reports of a decreased blood histidine concentration in rheumatoid arthritis, these studies provide a possible explanation for the affinity of this disease for joints.

Catalysis↗
PubMed1977

Interaction of cartilage proteoglycans with hyaluronic acid. The role of the hyaluronic acid carboxyl groups.

Hyaluronic acid-derived oligomers of five to fifteen repeat dissaccharides effectively bind to bovine nasal-cartilage proteoglycan and inhibit the interaction between proteoglycans and high-molecular-weight hyaluronic acid. If, however, the hyaluronic acid oligosaccharides are modified by reaction with diazomethane to form the carboxyl methyl esters of the glucuronic acid residues, their inhibitory activity is abolished. The binding capacity can be fully restored by saponification. The amide derivative, which is formed by condensation of the oligosaccharide carboxyl groups with glycine methyl ester, is also ineffective in blocking the proteoglycan-hyaluronic acid interaction. In this case, binding activity is not restored when the amidated oligomers are subjected to saponification to yield the free carboxylate groups on the glycine residues. Thus the displacement of the carboxylate groups on the polysaccharide chain by the interposition of a glycine residue blocks the interaction between the proteoglycans and the hyaluronic acid oligomers. When the oligosaccharide methyl ester is reduced with NaBH4, the resultant glucose-containing oligomers exhibit decreased binding to proteoglycans. Thus it appears that the hyaluronic acid carboxylate anion in a specific spatial orientation is required for hyaluronic acid-proteoglycan interaction.

Animals↗
PubMed1975

Studies on hyaluronic acid. V. Relationship between the protein content and viscosity of rooster comb dermis hyaluronic acid.

Protein accounted for an average of 8.7% w/w of the hyaluronic acid obtained from rooster comb dermis extracts and three types of peptide constituents appeared to be present. A few collagen-like fibers were closely associated with the hyaluronic acid when samples were examined in the electron microscope and collagenase treatment decreased the intrinsic viscosity from 7000-5000 ml/g to 3900-2700 ml/g. The quantities of collagen present, however, were too small to detect chemically with the methods employed. The major peptide consituent was readily separated from the hyaluronic acid by fractionation in a cesium chloride gradient or by treatment with pronase. The viscosity was decreased by the density gradient procedure but not by the pronase digestion. Repeated fractionation in a cesium chloride gradient decreased the intrinsic viscosity still further and a small peptide constituent with a high glycine and serine content remained associated with a hyaluronic acid. The data suggest that an interaction or entanglement with collagen fibers is responsible for the high viscosity of hyaluronic acid in this tissue extract and that the viscosity of purified hyaluronic acid preparations is dependent upon interactions between adjacent polysaccharide chains. Interactions between the major peptide constituent and polysaccharide chains or the small residual peptide component remaining with hyaluronic acid after extensive purification procedures, however, appear to be involved in some organized structure because the presence of the major peptide constituent minimized the decrease in viscosity that occurred when hyaluronic acid samples were lyophilized.

Amino Acids↗
PubMedDate not supplied

Hyaluronic acid produced by human synovial fibroblasts. Effect of polyinosinic-polycytidylic acid (poly I:C) and interferon.

Poly I:C (polyinosinic-polycytidylic acid) stimulated hyaluronic acid production by rheumatoid and non-rheumatoid human synovial fibroblasts. Stimulation was dose dependent and was inhibited by acetylsalicyclic acid and indomethacin. Poly I and Poly C, when separately added, had no stimulatory effect on hyaluronic acid production, and Poly A:U had only a slight effect on this parameter. Cells grown with Poly I:C were virus resistant and interferon was detected in their medium. Human interferon had also a dose-dependent stimulatory effect on hyaluronic acid production by synovial cells. A possible interferon-mediated relationship between virus infection and pathologic accumulation of joint fluid is suggested.

Arthritis, Rheumatoid↗
PubMed1979

Biosynthesis of hyaluronic acid by Streptococcus.

Synthesis of hyaluronic acid was investigated in a cell-free system derived from a strain of Group A streptococci. Preparative procedures were improved so that an enzyme system 70 times more active than that previously reported was obtained. The hyaluronic acid synthesized could be separated into trichloroacetic acid-soluble and -insoluble fractions. On the basis of pulse-chase experiments, it was shown that the trichloroacetic acid-insoluble fraction is a precursor of the soluble fraction. The release of the trichloroacetic acid-insoluble hyaluronic acid is specifically blocked with p-chloromercuribenzoate, without inhibition of chain elongation. The addition of butanol to trichloroacetic acid resulted in solubilization of all of the hyaluronic acid. No detectable difference in molecular size was observed between the two hyaluronic acid fractions, both of which were estimated to be more than one million daltons in size. Testicular hyaluronidase digestion of either one of the two types of hyaluronic acid yielded no high molecular weight fragments, indicating that hyaluronic acid is not bound covalently to protein. However, following incubation of enzyme assay mixtures with UDP-[14C]GlcUA, even in the absence of UDP-GlcNAc, radioactive high molecular weight hyaluronic acid was obtained which suggests that the enzyme system elongates rather than initiates hyaluronic acid chains. Tunicamycin did not inhibit hyaluronic acid synthesis, indicating lack of participation of an intermediate of pyrophosphorylpolyisoprenol type. The results obtained are consistent with the hypothesis that chain elongation of hyaluronic acid proceeds by alternate addition of monosaccharides from UDP-sugars by a membrane-bound synthesizing system followed by release of completed hyaluronic acid chains.

Carbohydrates↗
PubMed1977

Molecular weight of hyaluronic acid from rabbit skin.

Hyaluronic acid was prepared from adult rabbit skin. Defatted skin powder suspended in 0.5 M NaCl was homogenized, and total glycosaminoglycans were precipitated from this 0.5 M NaCl extract with cetylpyridinium chloride, then redissolved successively with increasing concentrations of NaCl and finally 0.5 N NaOH. Hyaluronic acid, the major acid glycosaminoglycan in the 0.5 M NaCl extract, was purified and fractionated by DEAE-Sephadex chromatography. The molecular weights ranged from 1 X 10(4) to 7.2 X 10(4). Alternatively, hyaluronic acid was obtained from adult rabbit skin without mechanical powdering and homogenizing. Defatted skin pieces were suspended in water and heated at 100 degrees, then the extract was digested with pronase followed by DNase [EC 3.1.4.5]. Glycosaminoglycans were excluded in gel filtration with Sephadex G-75. Hyaluronic acid and dermatan sulfate, the two major glycosaminoglycans of this tissue, were separated by gel chromatography on Sepharose 4B. The molecular weight of this hyaluronic acid ranged from 1.6 X 10(5) to 1.3 X 10(6). Yields of hyaluronic acid by these two methods were similar. Hyaluronic acid was probably degraded by the mechanical treatments in the first method. Other factors affecting the viscosity of the tissue extract were examined.

Animals↗
PubMed1976

Inhibition of proteoglycan biosynthesis by hyaluronic acid in chondrocytes in cell culture.

The depression of proteoglycan synthesis in ten-day-old high density chondrocyte cultures was shown to be dependent on both the concentration and time of exposure of the cells to hyaluronic acid. Hyaluronic acid had no effect on the overall protein synthesis by the cultured cells. Using benzyl-beta-D-xyloside an exogenous acceptor, it was shown that glycosaminoglycan biosynthesis by the chondrocytes was not affected by hyaluronic acid. It was concluded that hyaluronic acid was effecting glycosaminoglycan chain initiation, hence proteoglycan biosynthesis, either by specifically depressing the synthesis of the core protein or by repressing the activity of the xylosyltransferase.

Acetates↗
PubMed1977

Effects of adenosine 3':5'-cyclic monophosphate and serum on synthesis of hyaluronic acid in confluent rat fibroblasts.

A small amount of hyaluronic acid is synthesized in confluent cultures of rat fibroblasts, which have a high content of cyclic AMP. Addition of calf serum caused a rapid decrease in the cellular cyclic AMP content and large increases in hyaluronic acid synthetase activity and hyaluronic acid production. Addition of cyclic AMP also caused a marked increase in hyaluronic acid synthetase activity within 2h and then increased hyaluronic acid production. The effects of cyclic AMP and serum on hyaluronic acid synthesis were additive. Prostaglandin E2, which increased the cyclic AMP by stimulating adenylate cyclase, was as effective as cyclic AMP in increasing hyaluronic acid synthetase activity, but AMP was far less effective than cyclic AMP. These results indicate that cyclic AMP itself stimulates the mucopolysaccharide synthesis and that the effect of serum is not due to a decrease in cyclic AMP in the cells.

Animals↗
PubMed1976

Streptococcal bacteriophage 12/12-borne hyaluronidase and its characterization as a lyase (EC 4.2.99.1) by means of streptococcal hyaluronic acid and purified bacteriophage suspensions.

Hyaluronic acid was obtained from filtrates of heat-killed cultures of Streptococcus pyogenes group A, strain K56, by simple ethanol precipitation and treatment with an adsorbent. The hyaluronic acid is pure as judged from chemical and sedimentation analyses. Particles of streptococcal bacteriophage 12/12 were isolated from phage-lysed group A streptococci by polyethylene glycol precipitation and isopyenic centrifugation. Electron micrographs of negatively stained preparations showed a typical Bradley group B virus with a long, flexible, cross-striated tail and a knob- or star-like structure at the distal tip of the tail. The hyaluronic acid is depolymerized upon incubation with the phage 12/12 virions. After extensive digestion, a mixture of at least four oligosaccharides is formed, the two smallest of which are a tetra- and octasaccharide terminating in reducing N-acetyl-D-glucosamine. The tetrasaccharide shows an absorption maximum at 231.5 nm with a molar extinction coefficient epsilon = 4820 litres X mole-1 X cm-1, and it is therefore concluded that the bacteriophage-borne hyaluronidase catalyses a beta-elimination. Accordingly it is classified as a hyaluronate lyase (EC 4.2.99.1).

Bacteriophages↗
PubMed1979

Cell-free synthesis of hyaluronic acid in Marfan syndrome.

The cell-free synthesis of hyaluronic acid has been demonstrated in extracts of cultured human fibroblasts. Preparations from fibroblasts of normal individuals as well as those from patients with Marfan syndrome incorporate glucuronic acid and N-acetylglucosamine from their UDP derivatives into hyaluronic acid. Extracts from Marfan fibroblasts demonstrate 3 to 10 times more total and specific hyaluronic acid synthetase activity than do preparations from normal fibroblasts. All synthetic activity was found in particulate fractions with the bulk of activity localized in material sedimenting as large membrane fragments. Marfan and normal preparations exhibited similar properties with respect to substrate, cofactor, pH requirements, and heat stability. Neither the Marfan nor normal enzyme systems could be stimulated by exogenous acceptors, nor did either preparation contain a soluble factor which stimulated or inhibited the enzymic activity of the other. The genetic defect in Marfan syndrome appears to result in increased activity of hyaluronic acid synthetase without demonstrable changes in properties of the particulate enzymes involved.

Cell-Free System↗
PubMed1979

Hyaluronic acid vitreous substitute. A six-year clinical evaluation.

Hyaluronic acid vitreous substitute (HYVISC) was used during 347 operations performed on 294 eyes of 286 patients. It was injected intraocularly in 266 operations (73 scleral bucklings, 175 open-sky vitrectomies, among others) on eyes with complex retinal detachments that were considered inoperable by ordinary surgical techniques. During 81 closed vitrectomies, it was applied extraocularly between the surgical contact lens and the cornea. Hyaluronic acid was found to be well tolerated by human eyes. In eyes that had been given a poor prognosis, scleral buckling with hyaluronic acid tamponade produced reattachment in 16% of the eyes; open-sky vitrectomy, scleral buckling, and hyaluronic acid salvaged 18%. It also appeared helpful in the preservation of corneal epithelial integrity and clarity during closed vitrectomy.

Adolescent↗
PubMed1976

[Conformational changes of hyaluronic acid in acid medium (author's transl)].

Both vitreous body homogenate and a fibrous product containing hyaluronic acid and collagen isolated from vitreous humor by acetone precipitation were investigated to elucidate the liquefaction of vitreous body by acids. Graphic evaluation of the titration with hydrochlorid acid and viscosity measurements suggest a changed of the hyaluronic acid molecule in the pH-range between 5.2 and 4.1. Between these pH-values the ionization of carboxyl groups is decreased accompanied by conformational changes of the hyaluronic acid molecule. These results are in agreement with the conclusion of other authors that by lowering the pH of hyaluronic acid solutions a random coil to double helix transition of hyaluronic acid occurs.

Animals↗