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Biomedical subjects

G Embery

Publications and source records attributed to G Embery.

At least 91 records · Page 5Linked to original sources
PubMed1985

Glycosaminoglycans in human gingival crevicular fluid as indicators of active periodontal disease.

The glycosaminoglycans (GAG) in gingival crevicular fluid (GCF) were investigated by cellulose-acetate electrophoresis of samples from individual sites of defined conditions variously affecting the tissues of the periodontium. The non-sulphated GAG, hyaluronic acid, was present in all samples and was the only major band from sites of chronic gingivitis. An additional sulphated GAG band identified by enzymic digestions as chondroitin-4-sulphate, was detected in GCF from sites of untreated-advanced periodontitis. Initial samples from sites of early periodontitis and juvenile periodontitis yielded a similar additional band which was not detected, however, in samples collected after either surgery to eliminate deep pockets or daily subgingival irrigation with a chlorhexidine solution. Sulphated GAG was also present in fluid from the control situations, i.e. of teeth either undergoing orthodontic movement or showing evidence of trauma from occlusion, and from healing tooth-extraction wounds. Thus the presence of such a component in GCF correlates with those clinical conditions in which degradative changes are occurring in the deeper-periodontal tissues. The electrophoretic profile of GAG in a sample of GCF may be a sensitive laboratory method of indicating active phases of destructive periodontal disease at individual sites.

Chronic Disease↗
PubMed1985

Glycosaminoglycan-depolymerizing enzymes produced by anaerobic bacteria isolated from the human mouth.

A number of obligately anaerobic bacteria, some implicated in periodontal disease, were screened for their ability to produce enzymes capable of degrading hyaluronic acid and chondroitin-4-sulphate. Two screening methods were used following anaerobic incubation at 37 degrees C for 7 days. One involved incorporating the respective substrates and bovine-serum albumin into agar plates and, after incubation, flooding the plates with 2 M acetic acid. Clear zones were produced around colonies which produced enzymes capable of depolymerizing the substrates. The second was a sensitive spectrophotometric procedure based on the ability of certain bacteria to produce eliminase enzymes, which degrade the substrates to unsaturated products having a characteristic u.v. absorption at 232 nm. Strains of Bacteroides gingivalis and Bacteroides melaninogenicus degraded both substrates whereas Bacteroides asaccharolyticus degraded neither substrate by either method. Some bacteria gave negative results with the plate method whereas the more sensitive spectrophotometric assay proved positive. The number of anaerobic bacteria capable of degrading hyaluronic acid and chondroitin-4-sulphate in vitro may therefore have been underestimated in previous studies.

Bacteria, Anaerobic↗
PubMed1985

Structural studies on a sulphated glycoprotein preparation isolated from human saliva.

The identity of the sulphated component in a high-molecular-weight glycoprotein preparation (GP) from human whole saliva was investigated. A t0.5 of 96 min for inorganic sulphate release in 0.25 M HCl indicated the presence of O-substituted sulphate, probably associated with hydroxyl groups of sugar residues. This possible association of ester was also inferred from infra-red data of the intact GP, where major absorption bands were detected at 1230-1250 and 828 cm-1. Further a sulphated-monosaccharide derivative was released during acid hydrolysis in 0.1 M HCl at 100 degrees C for 75 min and isolated by gel-filtration on Sephadex G-15. This derivative was separated from a range of non-sulphated sugars by thin-layer chromatography in various solvent systems and possessed the chromatographic characteristics of N-acetylgalactosamine-6-O-sulphate.

Acetylgalactosamine↗
PubMed1984

Molecular size distribution of proteoglycans in human inflamed gingival tissue.

Proteoglycans were extracted from human gingiva with 2 M CaCl2. The extracts were examined by gel filtration on Sephacryl S-400 in 2 M CaCl2 under dissociative conditions. The 280 nm absorbance profiles of clinically uninflamed, inflamed and severely-inflamed tissues showed that material was present with molecular weights of between 2 X 10(6) or greater, and 16,000. Proteoglycans were examined by cellulose-acetate electrophoresis with subsequent identification of the constituent glycosaminoglycans after protease digestion, and finally by chondroitinase AC digestion of the liberated glycosaminoglycans. The relative proportion of each glycosaminoglycan was calculated by scanning each cellulose-acetate sheet on an integrating densitometer. Heparan sulphate was found only in fraction I (mol. wt 2 X 10(6) or greater), together with hyaluronic acid and chondroitin-4-sulphate, these being present in all of the glycosaminoglycan-containing fractions (I-IV). Dermatan sulphate was absent from fraction I, but present in II-IV, apparently existing on the same protein core as chondroitin-4-sulphate. The relative proportions of these two glycosaminoglycans was related to molecular size, and with the degree of inflammation for a given molecular species.

Chondroitin Sulfates↗
PubMed1984

Partial chemical characterization and biological activities of sulphated glycoproteins isolated from in-vivo pilocarpine-stimulated secretions of rat minor salivary glands.

Following the incorporation of [35S]-sulphate into rats, 35S-labelled sulphated glycoproteins were isolated from the minor salivary gland secretions of pilocarpine-stimulated, immobilized animals. The secretory products were initially resolved on Sepharose 4B into two major radioactive fractions, one of which appeared at the void volume and represented only 7 per cent by weight of the applied fraction. The bulk of the products were of lower molecular weight and were further resolved by DEAE-Sephacel anion-exchange chromatography. Four distinct radioactive fractions were obtained all of which possessed blood-group A reactivity and aggregated Streptococcus sanguis NCTC 7864 but not Streptococcus mutans OMZ61. The radioactive fractions possessed protein/carbohydrate ratios in the range 1.6:1-5.8:1. Ester-sulphate contents ranged from 2.5 to 5.3 per cent with a higher value of 14.0 per cent being obtained for the most anionic fraction. Sialic acid was in the range 5.1 to 21.6 per cent. None of the fractions tested contained sulphated glycosaminoglycans.

Animals↗
PubMed1984

Incorporation of inorganic [35S]-sulphate into glycoproteins of rat buccal and palatal minor salivary glands in vivo and in vitro.

The incorporation of sodium [35S]-sulphate into the buccal and palatal minor glands of the albino rat was studied in vivo and in vitro. The biosynthesis of 35S-labelled macromolecules possessing the characteristics of sulphated glycoproteins was evident in both. Uptake of [35S]-sulphate into the palatal tissue in vivo was more rapid (approx. 10-fold at 2 h) and produced compounds of higher specific activity by comparison with buccal extracts. Following in-vitro culture in the presence of [35S]-sulphate, the 35S-labelled glycoproteins secreted into the medium contained a greater proportion of lower molecular-weight products and were of higher specific activity (in the range 10-20-fold greater) than those in the tissue fraction. No sulphated glycosaminoglycans were apparent in any of the products isolated.

Animals↗
PubMed1982

Blood-group-reactive glycoprotein from human saliva interacts with lipoteichoic acid on the surface of Streptococcus sanguis cells.

[3H]-Glycerol-labelled lipoteichoic acid (LTA) was extracted from Streptococcus sanguis cells using aqueous phenol. Chemical analysis of the LTA yielded phosphate:glycerol:glucose:fatty acids in the mole ratio 1.0:0.97:0.76:0.03. The LTA inhibited the interaction between Strep. sanguis cells and a high mol. wt blood-group-reactive glycoprotein (BGR-glycoprotein) isolated from human saliva and reduced Strep. sanguis-mediated haemagglutination activity. Purified LTA from Strep. mutans strains OMZ61 and HS6, which have been shown not to interact with the BGR-glycoprotein, also inhibited the BGR-glycoprotein mediated aggregation of Strep. sanguis, as did an antiserum prepared against Lactobacillus casei LTA. It is proposed that the binding of the salivary glycoprotein to Strep. sanguis cells in achieved through LTA associated with bacterial surface fibrils.

Binding Sites↗
PubMed1980

The influence of fluoride administration on the structure of proteoglycans in the developing rat incisor.

1. 35S-labelled chondroitin 4-sulphate proteoglycan was isolated from the mineralized elements of the developing incisor teeth of Harvard rats receiving intraperitoneal administration of Na235SO4. 2. The chondroitin 4-sulphate proteoglycan underwent a decrease in molecular size in fluorotic teeth as judged by gel filtration on Sepharose 2B. 3. When examined by anion-exchange chromatography on DEAE cellulose-52, the proteoglycan from fluorotic teeth resolved into four peaks in comparison with the material from non-fluorotic teeth, which exhibited only a single major peak. 4. Both the single peak from non-fluoridated teeth and the four peaks from the fluorotic teeth were further resolved on cellulose acetate electrophoresis. 5. Isolated chondroitin 4-sulphate chains obtained from fluorotic teeth also were of smaller molecular size as judged by gel filtration on Sephadex G-150. 6. Some possible influences of fluoride on the metabolism of these connective-tissue components in the developing rat incisor are discussed.

Amino Acids↗
PubMed1980

Interaction between sulphated macromolecules and hydroxyapatite studied by infrared spectroscopy.

Transmission infrared spectroscopy has been used to study some aspects of the mechanism of binding of chondroitin-4-sulphate to hydroxyapatite. The disappearance of absorption maxima characteristic of the covalently bound sulphate groups indicates that these groups may be involved in bridging the chondroitin sulphate molecule to the crystal lattice of the hydroxyapatite. The technique may be valuable, both in studying the formation of organic films on tooth surfaces and the mechanisms of endogenous mineralisation.

Adsorption↗
PubMed1979

Interaction of acid glycosaminoglycans (mucopolysaccharides) with hydroxyapatite.

Selected acidic glycosaminoglycans (GAG) have been used as a model series to study some binding properties of hydroxyapatite. The order of binding was heparin, heparin sulfate, dermatan sulfage/chondroitin-4-sulfate/chondroitin-6-sulfate (all similar) and hyaluronic acid, indicating that the negative charge on the molecules is a major determinant in the binding process. Both calcium and saliva pretreatment led to an increase in uptake of selected GAG whereas fluoride even at 1 and 3 parts/106 levels led to a graded reduction in uptake. The clinical significance of these findings may be related to the presence of certain GAG in the dental integuments and to the interaction of a chemically defined group of compounds at a specific solid surface. Such findings may also have an application in studies on endogenous mineralization. The results are in accord with the generally held view that polyanions may interact electrostatically with calcium sites present in the crystal lattice of the hydroxyapatite.

Adsorption↗
PubMed1979

Possible origin of sulfated glycosaminoglycans in human dental calculus.

The sulfated glycosaminoglycans present in human dental calculus have been shown to be dermatan sulfate and chondroitin-4-sulfate. The composition suggests that the glycosaminoglycans present in calculus, particularly subgingival material, could originate as a result of associated periodontal disease since closely similar compounds have previously been identified in normal and inflamed human gingiva.

Dental Calculus↗
PubMed1977

A sulphated glycopeptide in human supragingival calculus extracts.

A method is described for the isolation and purification of a sulphated glycopeptide from human supragingival calculus. The compound was isolated after using EDTA treatment, 2 M CaCl2 extraction, proteolytic digestion, ethanol precipitation, and finally purified by DEAE cellulose chromatography. It migrated as a single component of cellulose acetate electrophoresis, and chemical and infrared spectral analysis showed the presence of covalently attached sulphate groups. The sulphated glycopeptide was distinguished from being a sulphated glycosaminoglycan.

Calcium Chloride↗