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Biomedical subjects

E Moczar

Publications and source records attributed to E Moczar.

At least 55 records · Page 3Linked to original sources
PubMed1977

Structural glycoprotein from the media of pig aorta. Aggregation of the S-carboxamidomethyl subunits.

Media of pig aorta was extracted with 1 M NaCl and 2 M MgCl2 to remove most of the soluble collagen, proteoglycans and glycoproteins. The glycoproteins remaining in the residue were extracted with 6 M urea-0.1 M mercaptoethanol. The urea soluble proteins were precipitated by dialysis, redissolved in 4 M guanidine-0.05 M DTT and were S-carboxamidomethylated (CM-guanidine extract). This extract was further fractionated by a variety of methods in order to separate a glycoprotein from collagen and proteoglycans. Caesium chloride density-gradient ultracentrifugation of the CM-guanidine extract separated a minor proteoglycan peak from a major glycoprotein fraction still containing some hydroxyproline. This major glycoprotein fraction was excluded as a single peak from Sephadex G 100 and G 200 in 4 M guanidinium chloride or in 6 M urea-0.2 per cent SDS. Sodium dodecylsulphate gel electrophoresis separated this high molecular weight Sephadex fraction into a major low molecular weight (approximately 35000 daltons) component and a minor high molecular weight component. This glycoprotein fraction could also be separated from a collagenous fraction and from proteoglycans by ion exchange chromatography on DEAE cellulose or by gelfiltration on Sepharose 4 B in 6 M urea-0.02 M EDTA-0.2 per cent SDS at pH 7.0. The isolated glycoprotein fraction is rich in dicarboxylic amino acids, contains galactose, mannose, (glucose), N-acetylglucosamine and sialic acid. The S-carboxamidomethyl glycoprotein preparation interacts with acid soluble calf skin collagen on isoelectric focusing in sucrose gradient in urea. This interaction is in favour of the biological role claimed for structural glycoproteins during fibrogenesis and differentiation.

Amino Acids↗
PubMed1977

Comparative study on the composition of the organic matrix of the long bones of the "normal" rat and of the mutant Op/Orl.

The organic matrix of the long bones of the "normal" rat strain and of its mutant Op/Orl were investigated. This latter strain exhibits some anomalles similar to Albers-Schönberg disease as well as tooth retentions. Bones (tibia, femur) were incubated with 14C-glucose and also submitted to a fractional extraction procedure (EDTA, urea) to separate soluble and insoluble fractions. The proteins, hexoses, hexosamines, hydroxyproline content of these fractions was determined as well as the radioactivity of the soluble extracts Glycosaminoglycans were also studied by cellogel electrophoresis after pronase digestion of the EDTA-extracts. Male and female animals of each strain were studied separately. The relative amount of soluble proteins (EDTA + urea extracts) was the same in both strains, the mineral content of the final residue was however higher in the mutant Op/Orl strain. The hydroxyproline content of the mutant-extracts were lower than in the original strain suggesting a lower soluble collagen content. This may be due to a faster polymerisation, insolubillisation of freshly synthesised collagen. The hexosamine content of the mutant urea extracts and the final residue was higher than that found in the analogous extracts obtained from the normal "normal" strain, suggesting a higher proportion of structural glycoproteins in the mutant bone, uronic acid being low or absent. Some other parameters were identical between the mutant and original strains but differed between males and females. The radioactivity of the soluble extracts was higher in the males than in females. The glycosaminoglycans of the EDTA extracts are also different: male-extracts show two bands on cellogel electrophoresis, one corresponding to chondroitin-sulphate, the other to hyaluronate. Females showed only the chondroitin sulphate band. The aminoacid composition of the insoluble residue of males was higher in basic amino acids (lysine, histidine, arginine) than the female extracts. These results indicate the existence of discrete well defined differences between the organic matrix of the orginal and mutant strain on one side and between male and female bones on the other side.

Amino Acids↗
PubMed1976

[Condensation of D-glycosamines with proteins].

4-O-beta-D-Galactopyranosyl-alpha,beta-D-glucopyranosylamine (lactosylamine), beta-D-gluco-, alpha- and beta-D-galacto-, and beta-D-manno-pyranosylamines were bound to the carbodiimide-activated carboxyl groups of lysozyme. Of the 11 free carboxyl groups of the protein, approximately 3 were substituted by alpha,beta-lactosylamine, and approximately 2 by the monohexosylamines. One of the 4 glycopeptides isolated from the tryptic digest of the lysozyme-lactosylamine conjugate was identical to synthetic 1-N-L-leucinoyl-4-O-beta-D-galactopyranosyl-beta-D-glucopyranosylamine, indicating the substitution of the carboxyl group of the C-terminal leucine residue. The isolation of a glycopeptide containing the aspartic acid residue in position 117 indicates that the second alpha,beta-lactosylamine residue is linked to the carboxyl group of this amino acid. Both of the 2 other glycopeptides contain the same free carboxyl groups (one glutamic and two aspartic acid residues in positions 35, 48, and 52, respectively). The third alpha,beta-lactosylamine residue seems to be linked to one of these carboxyl groups.

Amino Acids↗
PubMed1976

Biochemical studies on dacron arterial prostheses.

Dacron arterial prostheses, treated or not with biopolymers (gelatin, glycosaminoglycans) were implanted in the abdominal aorta of dogs and the connective tissue synthetised inside and outside the prosthesis was studied. After 3 and 9 months of implantation the prosthesis, a joining portion and a piece of aorta were excised and put in organ culture with 14C-lysine for 3 days. Representative macromolecular extracts were then obtained by a "chemical dissection" procedure. The radioactivity and the chemical composition of these extracts was studied. The DNA content of the prosthesis was higher than that of the adjacent aorta showing a dense cellular repopulation of the prosthesis. This was confirmed by histology also which revealed the presence of a newly formed limiting elastic membrane and the presence of numerous elastic fibrils. Collagen, elastin and glycosaminoglycans could be detected in the macromolecular extracts showing that the cells which repopulated the prosthesis expressed a complete biosynthetic capacity as far as matrix macromolecules are concerned. The distribution of proteins in the extracts was as follows: 4% of total proteins were extracted in a 1M CaCl2-buffer 80% of total proteins in the collagenase extracts, 10% in the 6M urea extract. Only 0,2% of proteins were in the final elastase extract, 10 times less than in the joining aorta fragment. The proportion of the other proteins was similar in aorta and in the prosthesis as well as the chemical composition (hexosamine and hydroxyproline content) of the extracts. The proportion of collagenase-extractable proteins decreased with the time of implantation (from 3 to 9 months) and the proportion of urea-extractable proteins increased. This type of modification is similar to that found in aging aorta wall. 14C-lysine was actively incorporated in all macromolecular fractions studied. The incorporation pattern of the prothesis tissue was similar to that found for the joining host aorta, showing a similar regulatory tendency for matrix macromolecules. It appears therefore that a valid hemocompatible vascular type of connective tissue can be synthesised on the dacron arterial prosthesis and nature of this connective tissue can be influenced by previous biopolymer treatment of the synthetic prosthesis. The described procedure (incorporation of labelled precursors in organ culture) appears to be a valid method for the exploration of the regulatory processes underlying the synthetic capacity for matrix macromolecules of the newly formed tissue in the synthetic prosthesis.

Animals↗
PubMed1976

Heterosaccharides derived from structural glycoproteins of the skin of two isogenic mouse (Mus musculus) strains C3H/He and C57BL/6.

1) Glycopeptides were prepared by pronase digestion of the urea extract of dermis of two isogenic mouse strains C3H/He and C57BL/6. 2) The major glycopeptide fractions from both strains contain, glucosamine, galactose, mannose, fucose and sialic acid. 3) The sugar composition, the behaviour on gel filtration and yields of the glycopeptides with identical electrophoretic mobilities, isolated from the two strains, were identical.

Animals↗