Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.36 (hyaluronidase)
 4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We compared the distribution of fibronectin and chondronectin within the matrix of canine articular cartilage. Fibronectin was found throughout the matrix as well as pericellularly. In contrast, chondronectin was observed predominantly associated with the cell or pericellular matrix. Interactions of these molecules with matrix components in the pericellular matrix probably differs, however, since concentrations of hyaluronidase which prevented detection of pericellular fibronectin allowed detection of chondronectin. Chondronectin and fibronectin were detected in osteoarthritic cartilage as well as in disease-free cartilage. Penetration of biotinylated fibronectin into cartilage from the external medium occurred only in osteoarthritic cartilage and proceeded only from the articular surface. Disease-free cartilage appeared to maintain a barrier to fibronectin penetration from the articular surface which was sustained even after the proteoglycan content was markedly depleted by incubation of cartilage with catabolin or lipopolysaccharide. In cartilage that was proteoglycan-depleted, the only detectable penetration of external fibronectin was from the cut surface.
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PMID:Immunohistochemical localization of fibronectin and chondronectin in canine articular cartilage. 328 48

The use of a hyaluronic acid-binding proteoglycan (hyaluronectin) as a probe for the detection of hyaluronic acid has facilitated the development of an indirect enzymo-immunological assay for hyaluronidase. Plastic microtest ELISA plates were coated with hyaluronic acid. Incubation with hyaluronidase led to the destruction of insolubilized hyaluronic acid in proportion to the hyaluronidase concentration of samples. Residual hyaluronic acid was assayed by its capacity to bind immune complexes made up of hyaluronectin supplemented with alkaline phosphatase-conjugated anti-hyaluronectin antibodies. The technique was very sensitive and permitted the detection of as little as 10(-10) NFU of bovine testicular hyaluronidase. Hyaluronidase was detected by this technique in human sera, bee venom and culture medium of human hepatoma cell lines.
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PMID:An indirect enzymoimmunological assay for hyaluronidase. 331 96

The endothelium of the rabbit thoracic aorta was removed from the vessel wall by one of two procedures, and the freshly exposed subendothelial surface was used for 125I-antithrombin III binding studies. Pretreatment of the subendothelium with either heparitinase or thrombin diminished the uptake of 125I-antithrombin III by up to 80%, whereas pretreatment with plasmin, hyaluronidase or FPR thrombin had little effect. Morphometric analysis of the subendothelium from enzyme-treated and -untreated tissues showed that, whereas plasmin, thrombin and heparitinase each caused a dramatic reduction of the large proteoglycan granules of the extracellular matrix, only exposure to heparitinase and thrombin caused a reduction in the small proteoglycans which populate the basement membrane of smooth muscle cells. Of the subendothelium-bound 125I-antithrombin III, more than 80% was efficiently removed by excess thrombin or by excess heparin. Evidence was obtained for the formation of high molecular weight thrombin-antithrombin III complexes. We conclude that antithrombin III binds largely to proteoheparan sulphate located in the basement membrane of the intimal smooth muscle cells for the purpose of inactivating certain proteases which arise during haemostatic change.
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PMID:Evidence that rabbit 125I-antithrombin III binds to proteoheparan sulphate at the subendothelium of the rabbit aorta in vitro. 333 2

Proteoglycans were extracted from 14-day chick embryo brains, which had been labelled in vitro with [35S]sulfate or 3H-labelled amino acids. 4.0 M guanidinium chloride (containing proteinase inhibitors) extracted 94% of the 35S-labelled glycoconjugates. Following cesium chloride equilibrium centrifugation, the proteoglycans in each fraction were characterized by chromatography on Sepharose CL-2B. The most dense fraction (D1), which contained no detectable non-proteoglycan proteins, contained a large, aggregating chondroitin sulfate proteoglycan in addition to small chondroitin sulfate and heparan sulfate proteoglycans. The less dense fractions (D2-D6) contained both small chondroitin sulfate and heparan sulfate proteoglycans. Removal of hyaluronate from the D1 sample by digestion with Streptomyces hyaluronidase in the presence of proteinase inhibitors showed that aggregation of the large chondroitin sulfate proteoglycan is hyaluronate-dependent. Aggregation was restored by re-addition of hyaluronate. Reduction and alkylation, which blocked aggregation of a cartilage A1 proteoglycan, did not interfere with aggregation of the large brain proteoglycan.
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PMID:Distribution in cesium chloride gradients of proteoglycans of chick embryo brain and characterization of a large aggregating proteoglycan. 334 55

Pseudoxanthoma elasticum is a genetic disease characterized by progressive mineralization of elastic fibers. Previous studies suggested that other components, apart from elastin, might be involved in the alterations of this connective tissue disorder (Martinez-Hernandez and Huffer, 1974; Pasquali Ronchetti et al., 1981; 1986). Evidence is presented that proteoglycan metabolism is altered in PXE-affected patient. Urinary GAGs suggests an increased degradation of glucosamine-containing GAGs in the patient. Pulse and chase experiments on in vitro skin fibroblasts indicated a decreased rate of synthesis of [35SO4] containing GAGs or an increase of their turnover rate in PXE. Moreover, when PGs produced from skin fibroblasts were identified by ultracentrifugation and gel filtration in associative conditions, PXE fibroblasts produced a significantly higher amount of the high molecular weight fraction of sulfated PGs. This high molecular weight material was present both in the medium and in the matrix and disappeared under dissociative conditions or after treatment with hyaluronidase or with pancreas elastase. By electron microscopy, PXE fibroblasts appeared to produce and secrete an enormous amount of toluidine blue 0 positive material organized as filaments and amorphous masses. These data are in agreement with previous observations of the presence of abnormal masses of microfilaments, in the dermis of PXE patients, which were sensitive to hyaluronidase and partially to trypsin and elastase (Pasquali Ronchetti et al., 1986). The results seem to confirm that at least some of the alterations of connective tissues in PXE are due to abnormal PGs metabolism and to their tendency to form abnormal aggregates in the extracellular space.
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PMID:Pseudoxanthoma elasticum (PXE): ultrastructural and biochemical study on proteoglycan and proteoglycan-associated material produced by skin fibroblasts in vitro. 334 48

The present study reports on the fine structure of human costal cartilage at different ages in order to obtain information on the morphogenesis of amianthoid fibers. Our results reveal an overall increase of collagen fibril diameter with increasing age, even in areas with no signs of amianthoid transformation. Ultrastructural evidence is presented that this increase in diameter is due to a gathering of the preexisting collagen fibrils. The age-related change in collagen fibril diameter is paralleled by changes in the composition and ultrastructural appearance of cartilage proteoglycans (as revealed by acridine orange staining). Acridine-orange-positive filaments indicative for proteoglycans are markedly reduced in size with advancing age in centrally located regions of costal cartilage. Treatment with testicular hyaluronidase previous to acridine-orange staining leaves these small proteoglycan filaments unaffected. By contrast, the filaments visible after acridine-orange staining in the extracellular matrix near to the perichondrium are susceptible to hyaluronidase treatment. Infrequently, a sharp increase in collagen fibril diameter can be observed in territorial matrix areas of degenerating chondrocytes. This observation is conspicuous at ages of 10 and 20 years. Amianthoid transformation is characterized by the appearance of collagen fibrils strictly arranged in parallel. These amianthoid fibers are embedded in a matrix rich in small acridine-orange-positive filaments similar to the proteoglycan filaments observed in centrally located matrix regions. It can be concluded that extensive remodelling not only of the collagen fibrils but also of the cartilage proteoglycans is involved in the development of amianthoid transformation.
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PMID:Amianthoid (asbestoid) transformation: electron microscopical studies on aging human costal cartilage. 334 45

Primary and first passage rabbit chondrocyte cultures synthesized a "free" form of hyaluronic acid (HA-f) previously characterized in rabbit cartilage. HA-f was isolated from the [3H] glcN/35SO4-labelled cell-associated-fraction (CAF) and from the culture medium by successive equilibrium centrifugations in Cs2SO4/CsCl/Cs2SO4 under low salt conditions. The culture medium HA-f appeared in the void volume of Sepharose CL-2B eluted with low salt, (0.5M sodium acetate), and was susceptible to digestion with Streptomyces hyaluronidase. HA-f aggregated purified rabbit cartilage proteoglycan monomer. These results indicated that HA-f probably subserves hyaluronic acid already complexed with proteoglycan monomer. Newly synthesized HA-f may be required for the continual formation of proteoglycan aggregates.
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PMID:Synthesis of a "free" form of hyaluronic acid by articular chondrocytes in monolayer culture. 345 99

The role of hyaluronic acid in limb morphogenesis (chondrogenesis) has been well defined. In the present study, we found that hyaluronic acid synthesis in somite explants steadily increased until day 6, then decreased, and inclusion of notochord did not accelerate the rate of synthesis. Analysis of hyaluronidase activity in the somite explants indicated an increase in the enzyme level in day-6 cultures. Again, inclusion of notochord did not alter this pattern. The decrease in hyaluronic acid after day 6 and the increase in sulfated proteoglycan synthesis from day 6 resemble the pattern described during limb development. Subsequent studies showed that, with time, the size of the hyaluronic acid synthesized by somites increased and, again, inclusion of notochord did not influence this pattern. The results indicate that unstimulated somites are capable of synthesizing cartilage-specific proteoglycans in a relatively restricted manner, and the inclusion of notochord resulted in accelerated synthesis of stable proteoglycan aggregates typical of differentiated chondrocytes. Metabolic events in somites related to hyaluronic acid are not influenced by the notochord.
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PMID:Somite chondrogenesis in vitro: 2. Changes in the hyaluronic acid synthesis. 348 39

A solid-phase assay for detecting the binding of cartilage proteoglycan (PG) to hyaluronic acid (HA) is described. In the assay, HA is immobilized on protamine-treated microtiter wells, the wells are incubated with PG monomer and antibody to PG monomer, and then an ELISA system is used to detect binding of the PG to HA. The specificity of the assay is indicated by the failure to detect PG binding to chondroitin sulfate or albumin-coated microtiter wells, the absence of binding with tryptic fragments of PG monomer other than the HA-binding segment, the loss of binding after reduction and alkylation of PG monomer, and the inhibition of binding by preincubation of PG monomer with small amounts of HA. In contrast to the HA-PG interaction in solution, hyaluronidase digestion of HA does not affect its ability to inhibit the reaction of PG monomer with immobilized HA. The microtiter well-based assay appears to be a rapid, simple, and potentially versatile method for studying interactions with HA.
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PMID:A solid-phase immunoassay for the binding of cartilage proteoglycan to hyaluronic acid. 357 71

The method of human gallbladder epithelial cell culture has been developed successfully with active mucus secretory function. Human gallbladder epithelial cells were dissociated by Dispase digestion from the specimens obtained by cholecystectomy for uncomplicated gallbladder stone cases. The dissociated cells formed a monolayer in Eagle's minimum essential medium supplemented with 10% fetal bovine serum within 24 h after the inoculation. These cells were maintained for at least 2 wk without fibroblastic overgrowth. Cultured cells contained periodic acid Schiff-positive material in cellular cytoplasm for 3 d. On transmission electron microscopy these materials were identified as mucous secretory granules. Mucous secretory function was determined by [3H]glucosamine incorporation. Sixty percent of the secreted glycoproteins labeled with [3H]glucosamine was eluted in excluded fractions of Sepharose 4B gel filtration, which were considered to be mucous glycoprotein, because they were found to be resistant to proteoglycan-specific enzymes such as hyaluronidase, chondroitinase ABC, heparitinase, and heparinase. The mucous glycoprotein secretion was maintained for 3 d and found to be inhibited in a dose-dependent manner by monensin (10(-7) to 10(-5) M) which is a known blocker of secretory function.
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PMID:Demonstration and maintenance of mucus secretion in cultured human gallbladder epithelial cells. 362 58


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