Hyaluronidases reaction with

Even less is known about the effects of ozone on carbohydrates. Buell et al. observed a decrease in the depolymerization of hyaluronic acid after treatment of the lungs of ozone-exposed rabbits (1 ppm for 1 h) with hyaluronidase. B. Goldstein et al. reported a loss in membrane neuraminic acid of red cells exposed in vitro to high concentrations of ozone. It would be important to study the effects of ozone on respiratory tract mucus, which is rich in carbohydrates, including neuraminic acid. This could indude determination of foe extent to which ozone is able to penetrate mucus that is unaltered, whether foe reaction of ozone with mucus results in the formation of cytotoxic intermediates, and evaluation of the interaction in mucus of ozone with other air pollutants, particularly sulfur dioxide. Of possible pertinence is a study by Falk et who observed that ozone produced a loss in foe viral hemagglutinating ability of snail mucus. 

The acrosome reaction is the loss of the acrosomal and plasma membranes in the acrosome region and the release of acrosin, hyaluronidase and other enzymes that disperse the cumulus complex and allow the sperm to penetrate the zona pellucida. After capacitation and the acrosome reaction, sperm penetrate the extracellular cumulus matrix and bind with zona protein 3, a heavily glycosylated protein of the zona pellucida. The first segment of the sperm to make contact with the oolemma is usually the inner acrosomal membrane, followed by the postacrosomal region. The plasma membrane of the sperm attaches to microvilli on the oolemma. Sperm-egg fusion is apparent from reduced movement of the sperm tail (Yanagimachi, 1970,1988 Takano et al.,... 

Increased HA levels in the bloodstream decrease immune competence.153 Various mechanisms have been invoked. An HA coating around circulating lymphocytes may prevent ligand access to lymphocyte surface receptors.95 96 154 155 The increased HA may represent one of the mechanisms for the immunosuppression in the fetus. The reappearance of high levels of HA in old age may be one of the mechanisms of the deterioration of the immune system in the elderly. The increasing levels of HA with aging may be a reflection of the deterioration of hydrolytic reactions, including the hyaluronidases that maintain the steady state of HA. This is a far more likely mechanism than an increase in HA synthase activity. 

Histochemical methods will not differentiate between the isomeric chondroitin sulfates, and identification with any degree of certainty requires isolation of the mucopolysaccharide. A method has been reported (M8) that differentiates mucopolysaccharides sulfated at C-6 from other sulfated mucopolysaccharides, and depends on application of the Mor-gan-Elson reaction to the oligosaccharides released by the action of testicular hyaluronidase. It is well known that substitution at C-6 does not interfere with the Morgan-Elson determination of A -acetylhexo-samines, whereas the chromogens are not formed in significant amount if C-4 is substituted. 

Among several antidotes for the treatment of vinca alkaloid extravasation, hyaluronidase is the most effective (79). Seven patients with extravasation of vincristine, vinblastine, or vinorelbine received hyaluronidase 250 units diluted in 6 ml of 0.9% saline, through the indwelling needle or, when the needle had been already removed, as six subcutaneous injections around the extravasation site. None developed skin necrosis. Local mild skin warming in order to produce local vasodilatation may have an additional beneficial effect, but should be avoided when simultaneous extravasation of a vinca alkaloid and an anthra-cycline is suspected, because local warming can worsen the anthracycline-associated local reaction, whereas local cooling, which is generally beneficial in anthracycline-related extravasation alone, can worsen skin necrosis due to vinca alkaloids (76). 

Hyaluronidase has practically no serious side effects, although intravenous administration may be associated with severe allergic reactions. The use of highly purified preparations should reduce the likelihood of allergic complications. A clinical and histological study has investigated the safety of intravitreal... 

The current method for the hyaluronidase assay described in the United States Pharmacopeia (USP) [132] is based on the inability of hydrolyzed potassium hyaluronate to form a complex precipitate with proteins from added serum, reflected in a decreased turbidity of the reaction mixture (measured after 30 min). The method is, from the enzymological point of view, not well defined since it does not actually evaluate the kinetics of the hydrolysis of the substrate. An assay with end-point determination is only valid if the reaction rate does not change during this reaction time. We found that only with the two lowest test concentrations (0.15 and 0.3 IU) was this condition fulfilled, while with the three higher test concentrations the reaction is not linear. Commercially available hyaluronates can be contaminated with chondroitin sulfates. They are more acidic than hyaluronic acid itself and hence can form better protein complexes and influence the turbidity. In a suitability test of the USP [133], the substrate must pass both an inhibitor content test and a turbidity-production test. The assumption is made that... 

The response (a decrease of viscosity) is a direct consequence of the action of the enzyme on its substrate, since the splitting of the glycosidic bonds gives a decrease in the viscosimetric average molecular weight and hydrodynamic volume of the hyaluronan chains and hence a decrease in the intrinsic and relative viscosities. With this method the rate at different concentrations cannot be compared because the initial viscosities are different and rheological measurements do not coincide. To eliminate these problems, a kinetic dilution methodology for the viscosimetric study of the substrate concentration dependence of the action of hyaluronidase was proposed [135,136]. We were able to determine the rate of reaction, expressed as the number of moles of bonds broken per unit of time, from viscosimetric data [136]. 

The substrate for this assay consists of hyaluronan with the reducing terminals labeled with the fluorogenic reagent 2-aminopyridine [144], It should be noted that the reaction products by hyaluronidase also contain oligosaccharides that do not contain the fluorogenic end group. As these products are not detectable by this method, not all scissions occurring in the substrate are detected. 

Several investigations have reported the ability of some natural quinones to be therapeutically useful in the treatment of asthma. The natural anthraquinone chrysophanol-8-O-P-D-glucopyranoside has potent inhibitory activity on hyaluronidase, a enzyme released from mast cells and passive cutaneous anaphylaxis reactions [311], Cheng et al. [312] described the inhibitory effect of 9,10-anthraquinone 2-carboxylic acid on immunoglobulin E-mediated passive cutaneous anaphylaxis reaction. Furthermore, these compounds are promising for treating allergic diseases with chronic and severe pruritus. Lawsone, Fig. (12), 2-hydroxy-3-(2-hydroxyethyl)-l, 4-naphthoquinone and 2,2 -methylenebis(3-hydroxy )-l,4-naphthoquinone... 

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