Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.6.4 (chondroitinase)
 2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An in vitro model is presented for the study of glycosaminoglycans in human skin. The synthesis of six glycosaminoglycan species in both dermis and epidermis was measured by D-[3H]glucosamine labelling. Punched biopsies (epidermis + entire dermis) of 3 mm in diameter were cultured at 37 degrees C in 5% carbon dioxide-95% air. When the label was added 18 h after explantation, the incorporation started immediately, and for all glycosaminoglycans the time-dependent incorporation was linear for 16 h. The experimental variation was minimized by expressing the measurements in epidermis "per explant" and in dermis "per mg of wet explant". A ratio to dermal hydroxyproline did not improve the precision. Most of the variation arose "before" isolation and separation of the glycosaminoglycans. The labelled products were macromolecules and were converted to small molecules by chondroitinase ABC + heparinase. The total incorporation in dermis was 2 1/2 times higher than in epidermis. Hyaluronic acid was the predominant synthesized product in dermis, and hyaluronic acid and heparan sulphate were the predominant products in epidermis. The proportions (%) in dermis/epidermis were as follows: hyaluronic acid, 61/44; heparan sulphate, 18/31; dermatan sulphate, 5/8; chondroitin 4/6-sulphate, 10/7 and heparin-like glycosaminoglycan, 1/2. The same species were also demonstrated as native constituents of uncultured human skin. Hyaluronic acid and dermatan sulphate predominated in dermis, whereas no single species predominated in epidermis. Their concentrations in uronic acid equivalents per mg of wet skin (pmol/mg of epidermis + dermis) were as follows in dermis/epidermis: hyaluronic acid, 243/0.48; heparan sulphate, 22/0.44; dermatan sulphate, 170/0.56; chondroitin 4/6-sulphate, 72/0.50; and heparin-like glycosaminoglycan, 5/0.22. Thus, only 0.4% of the in vivo synthesized glycosaminoglycan was present in epidermis.
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PMID:D-[3H]glucosamine labelling of epidermal and dermal glycosaminoglycans in cultured human skin. 338 61

Cartilage resurfacing by chondrocyte transplantation, using porous collagen matrices as a vehicle to secure the cells in cartilage defects, has been used experimentally in animals. This in vitro study evaluated the temporal morphologic features and proteoglycan synthesis of chondrocyte-laden collagen matrices. Forty-two porous collagen disks were implanted with a minimum of 6 x 10(6) viable chondrocytes, covered by a polymerized collagen gel layer, and 6 disks were harvested after 0, 3, 7, 10, 14, 18, or 22 days of incubation in supplemented Ham's F12 medium at 37 C and 5% CO2. Histologic and histochemical evaluation of formalin-fixed segments of the cultured disks indicated that the chondrocytes proliferated in the implant, producing small groups and linear segments of cells by day 14. The collagen framework remained intact over the course of the study with thick areas attributable to depositions of matrix material after day 10. Alcian blue-stained matrix was evident in the pericellular region of chondrocytes in sections of disks harvested on days 14, 18, and 22. Glycosaminoglycan (GAG) assay by dimethylmethylene blue dye binding after papain digestion of the disk segments revealed negligible amounts of GAG at day 0. Significant (P < or = 0.0001) increase in total GAG content was observed by day 3 (0.329 micrograms/mg of disk) and further increases were observed until a plateau in GAG quantity was seen on day 14. Mean peak GAG content was 0.553 +/- 0.062 micrograms/mg. Secondary treatment of the papain-digested implants with keratanase and chondroitinase ABC yielded similar trends in chondroitin sulfate (CS) and keratan sulfate (KS) concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Temporal matrix synthesis and histologic features of a chondrocyte-laden porous collagen cartilage analogue. 843 Sep 45

Using an in vitro rat incisor odontoblast system, the effect of fluoride on proteoglycans was investigated at both the metabolic and structural level. Incisors were removed from 4-week-old rats, split longitudinally, and the pulps removed. Teeth were incubated at 37 degrees C, 5% CO2 in Eagle's Minimum Essential Medium containing 35S-sulfate for 7 hours in the presence of 0 mM, 3 mM, or 6 mM sodium fluoride. Teeth were demineralized in EDTA, proteoglycan was extracted from the residue with 4 M guanidinium chloride, and further purified by anion exchange chromatography. Uptake of radiolabel was monitored by liquid scintillation counting. The resultant products were examined by cellulose acetate electrophoresis, SDS-PAGE, chondroitinase digestion, and amino acid analysis. Differential effects of fluoride were observed in both metabolism and biochemical characterization of proteoglycans following incubation at the two concentrations. Fluoride decreased uptake of the radiolabel but led to an accumulation of glycosaminoglycan within the proteoglycan of the matrix. Chondroitin sulfate was the predominant glycosaminoglycan identified, with the additional presence of dermatan sulfate and heparan sulfate identified. Dermatan sulfate levels increased in 3 mM-treated teeth. Fluoride-treated proteoglycans had a reduced molecular weight (200-90K to 180-79K); this reduction is primarily a result of smaller glycosaminoglycan chains, with limited reduction in the size of the core protein of 6 mM-treated teeth occurring. Such alterations in the biochemical metabolism and hence structure and function of proteoglycan may be implicated in the hypomineralization seen in fluorosis.
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PMID:The influence of fluoride on proteoglycan structure using a rat odontoblast in vitro system. 850 77