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Biomedical subjects

D S Jackson

Publications and source records attributed to D S Jackson.

At least 91 records · Page 5Linked to original sources
PubMed1968

Carbohydrate content of bovine collagen preparations.

Collagen preparations from bovine tissues were analysed for their carbohydrate content. Crude preparations of tropocollagen and polymeric collagen were found to be contaminated with considerable amounts of mannose, fucose and hexosamine, sugars known to be present in the mucoprotein of the interfibrillar material with which collagen is associated in vivo. A pure preparation of tropocollagen obtained by ethanol precipitation procedures contained only galactose and glucose in the approximate ratio of 7:3 residues/3000 amino acid residues. Purification of crude polymeric collagen by EDTA extraction or by crude bacterial amylase extraction considerably decreased the mucoprotein contamination, particularly in the enzymic treatment, which yielded a preparation containing predominantly galactose and glucose in the ratio of 4:2 residues/3000 amino acid residues. The results confirm previous work that demonstrated the purity of these collagen preparations as inferred by amino acid analysis. The results also indicate the suitability of the pure tropocollagen and the amylase-extracted polymeric collagen for studies on the role of the carbohydrate residues in intramolecular and intermolecular cross-linking in collagen.

Amylases↗
PubMed1967

Purification and amino acid composition of monomeric and polymeric collagens.

The preparations and amino acid compositions of highly purified tropocollagen and insoluble polymerized collagen are described. These collagens appear to be very suitable for comparative studies in an investigation of the cross-linkages that are introduced into tropocollagen during the formation of polymerized collagen.

Achilles Tendon↗
PubMed1967

The changes in chemical composition during development of the bovine nuchal ligament.

Whole bovine nuchal ligaments, or portions thereof (in the case of commercially valuable animals), were obtained from 45 animals (28 fetal and 17 postnatal) ranging in age from 110 days of gestation to 10 yr. Insoluble elastin was quantitatively prepared from the fresh ligaments by extraction with hot alkali and by a combination of multiple extractions with alkaline buffer and then repeated autoclaving. When adult samples were examined, the yields of insoluble residue by these two methods were very similar, but with young fetal samples the second method gave significantly higher values, because of incomplete purification of the elastin residue. The changes in the concentration of collagen, alkali-insoluble elastin, and DNA have been examined. DNA concentration, and, thus, cell population density, fell progressively during the fetal period of development, to reach a steady value soon after birth. Collagen appeared in appreciable quantities before elastin, but its concentration was rapidly halved at about the time of birth. Insoluble elastin concentration was low until the end of the 7th fetal month, at which time it began to rise rapidly. The rate of increase in elastin concentration remained high throughout the next 10-12 wk, by which time the adult value had been reached. Quantitative studies, on the basis of the whole ligament, showed that the total cell content rises to a maximum at birth, but falls soon after to a level about half that at birth. Total collagen production and elastin deposition continue at a steady, maximal rate over the interval from 235 days of gestation to the end of the 1st postnatal month. It is concluded that the immediate postnatal period would be the most favorable phase in which to attempt the isolation of the soluble precursor elastin.

Amino Acids↗