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Biomedical subjects

J C Anderson

Publications and source records attributed to J C Anderson.

At least 199 records · Page 11Linked to original sources

Interaction between proteoglycan subunit and type II collagen from bovine nasal cartilage, and the preferential binding of proteoglycan subunit to type I collagen.

We studied the interaction of proteoglycan subunit with both types I and II collagen. All three molecular species were isolated from the ox. Type II collagen, prepared from papain-digested bovine nasal cartilage, was characterized by gel electrophoresis, amino acid analysis and CM-cellulose chromatography. By comparison of type I collagen, prepared from papain-digested calf skin, with native calf skin acid-soluble tropocollagen, we concluded that the papain treatment left the collagen molecules intact. Interactions were carried out at 4 degrees C in 0.06 M-sodium acetate, pH 4.8, and the results were studied by two slightly different methods involving CM-cellulose chromatography and polyacrylamide-gel electrophoresis. It was demonstrated that proteoglycan subunit, from bovine nasal cartilage, bound to cartilage collagen. Competitive-interaction experiments showed that, in the presence of equal amounts of calf skin acid-soluble tropocollagen (type I) and bovine nasal cartilage collagen (type II), proteoglycan subunit bound preferentially to the type I collagen. We suggest from these results that, although not measured under physiological conditions, it is unlikely that the binding in vivo between type II collagen and proteoglycan is appreciably stronger than that between type I collagen and proteoglycan.

Amino Acids↗

Experimental mycoplasma mastitis in mice.

Thirteen strains of mycoplasma representing six different species, Acholeplasma laidlawii, Mycoplasma dispar, M. bovirhinis, M. bovigenitalium, M. agalactiae subsp. bovis, and M. mycoides subsp. mycoides, were inoculated into the mammary glands of mice, and the number of mycoplasmas present in the glands three days after inoculation was determined. The predominant response included involution of inoculated glands and a neutrophil infiltration. With the exception of M. dispar, the pathogenicity of the six species for mice was found to be similar to their pathogenicity for cattle.

Acholeplasma laidlawii↗

Routine freezing of red blood cells for transfusion in Western Australia.

Experience with preservation of red cells for transfusion since 1971 has shown that refrigeration with liquid nitrogen is simple and reliable. It allows the use of a concentration of glycerol (20%) which can reasonably be removed by batch-washing if automated washing is not possible. It is possible to transport cells frozen in liquid nitrogen over long distances. This appears the method of choice for preserving rare blood, and once adopted for this purpose it is logical to use it for storage of red cells for other patients. Red cells so stored are similar in many respects to fresh cells, and more than 600 units have been transfused since 1971 without any adverse reaction.

Australia↗

The increased resistance of mice to experimental staphylococcal mastitis following inoculation of endotoxin.

Intramammary inoculation of endotoxin in mice three days before intramammary challenge with staphylococci induced resistance to the staphylococci. Endotoxin given by the intraperitoneal route also induced resistance when inoculated three days before challenge. Resistance was not induced, however, if the mice were allowed to continue lactating during the induction period. Histological examination of mammary glands following different combinations of lactation/involution and endotoxin treatment indicated that endotoxin given by either the intramammary or the intraperitoneal route caused an accelerated involution of the mammary gland and suggested that the involuted gland was inherently more resistant. This was confirmed by demonstrating the same resistance in mice after five days of natural involution when the mammary glands had reached the degree of involution produced by endotoxin in three days.

Animals↗

Isolation of a glycoprotein and proteodermatan sulphate from bovine achilles tendon by affinity chromatography on concanavalin A-Sepharose.

A fraction was isolated from a 3 M MgCl2 extract of bovine achilles tendon on the basis of its affinity for collagen. Affinity chromatography of this material on concanavalin A-Sepharose yielded a mixture which comprised a glycoprotein of approximate molecular weight 60 000 and two constituents containing hexuronic acid. The existence of a complex between the glycoprotein and material containing hexuronic acid was demonstrated by chromatography on Sephadex G-200 and by equilibrium sedimentation in CsCl density gradients. The complex was completely dissociated in 4 M guanidinium chloride. One of the constituents containing hexuronic acid was identified as a proteodermatan sulphate of low molecular weight and which had an abnormally high protein content (45-50%) and low buoyant density (1.46 g/ml) for a proteoglycan. The denser of the two molecules containing hexuronic acid appeared to be a normal proteoglycan, with a low protein content (11%). Analyses are given for the glycoprotein and the proteodermatan sulphate.

Achilles Tendon↗

The isolation of collagen-associated proteoglycan from bovine nasal cartilage and its preferential interaction with alpha2 chains of type I collagen.

A collagen complex from bovine nasal cartilage was prepared by extraction of the tissue with 3M-MgCl2 solutions, by using two different procedures. When it was compared with calf skin acid-soluble tropocollagen by polyacrylamide-gel electrophoresis, the 3M-MgCl2-soluble cartilage collagen in the complex appeared to be predominantly type I in nature, consisting of both alpha1 and alpha2 chains. The soluble cartilage collagens were digested with purified bacterial collagenase, and the soluble digests were fractionated on Sepharose 4B. Hydroxyproline-free proteoglycan was isolated in the excluded volume of the column eluate, and this was found to be an aggregate which could be dissociated to link proteins and proteoglycan subunit by equilibrium-density-gradient centrifugation in a CsCl-4M-guanidinium chloride gradient. Interaction with calf skin-soluble tropocollagen was studied by CM-cellulose chromatography. The link-protein system did not interact, but proteoglycan from the bottom of the gradient did interact. In addition, when proteoglycan subunit was allowed to interact with collagen, there was a preferential binding to the alpha2 and beta12 components, and this effect was also observed with the proteoglycan material obtained from the collagenase digests of 3M-MgCl2-soluble cartilage collagen complexes. However, specificity for alpha2 and beta12 chains was not exhibited by chondroitin sulphate glycosaminoglycan, and it is therefore concluded that preference for alpha2 and beta12 chains is a function of the intact proteoglycan structure.

Animals↗

The preparation of a bacterial collagenase containing negligible non-specific protease activity.

A three stage procedure for the purification of crude bacterial collagenase is described. The three stages were ion exchange chromatography on SP-Sephadex and DEAE-cellulose, followed by molecular sieve chromatography on Sephadex G-200. The end product was eluted from Sephadex G-200 as a single peak of absorbance at 280 nm, and a single zone of activity against gelatin. The active eluate was divided into two halves, designated fraction 1 and 2 collagenase. Their activities were greater than those of commercially available collagenases when assayed viscometrically against pepsin solubilized collagen from guinea-pig skins. The non-specific protease activities in both fractions were much less than in the commercially available purified collagenases, and fraction 1 collagenase liberated only 2.6% of a [3H]-tryptophan label from a substrate of 2 mg of labelled chick embryo proteins, after an 18 hour incubation. When polymeric collagen was incubated with fraction 1 collagenase, at a final enzyme : substrate ratio of 1:160, the collagen was digested, resulting in the loss of 99.8% hydroxyproline as dialysable material.

Animals↗

Production of mastitis in mice with human and bovine ureaplasmas (T-mycoplasmas).

Five ureaplasmas (T-mycoplasmas) of human origin and four of bovine origin were inoculated into the mammary glands of mice. The strains multiplied and neutrophils were observed in sections of infected glands. Some of the glands were macroscopically inflamed, albeit slightly, at necropsy but none of the mice showed any sign of disease during the course of the experiments. All nine ureaplasma strains produced mastitis in BSVS mice and the mammary glands of mice appear more susceptible to ureaplasmas than the udders of cows or goats. Mouse mastitis is suggested as being a suitable small animal model for studying ureaplasma infections.

Animals↗