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Biomedical subjects

A R Moore

Publications and source records attributed to A R Moore.

At least 73 records · Page 4Linked to original sources
PubMed1986

Degradation of cartilage in contact with soft tissue.

Observations have been made on histological changes in femoral-head articular cartilage transplanted into soft tissue in rats under a variety of conditions. Articular cartilage was implanted either whole or minced. Implants were made into deflated subcutaneous air pouches with or without an inflammatory irritant and into normal subcutaneous tissue. Cartilage-matrix loss occurred in four patterns: marginal zone encroachment, loss of metachromatic staining without loss of tissue mass, surface invasion and lacunar enlargement and coalescence. The presence of an inflammatory reaction had no discernible effect on loss of cartilage matrix. Changes at the marginal zone preceded changes at the centre. Loss of metachromatic staining without loss of tissue mass occurred in areas of chondrocyte death. Surface invasion was not affected by the viability of the underlying chondrocytes. Surface invasion occurred earliest in cartilage transplanted into subcutaneous tissue, and latest in cartilage implanted into air pouches inflamed with carrageenan. The onset of surface invasion appeared to be dependent on soft-tissue adhesion to the cartilage surface. Mincing of cartilage was associated with an increase in surface invasion in the deeper cartilage zone with large lacunae but not in the superficial zone with small lacunae. Occasional cut surfaces showed outgrowth of new cartilage matrix. These observations on artefactual modes of cartilage degradation may assist in analysing the critical steps in cartilage degradation in arthritic joints.

Air↗
PubMed1985

Studies into the association between leucocyte accumulation and oedema formation.

We have treated rats with methotrexate to reduce their circulating leucocyte numbers and in particular their polymorphonuclear leucocytes. Injection of zymosan, calcium pyrophosphate dihydrate crystals, carrageenan or dextran into rat pleural cavities induced leucocyte accumulation and oedema formation both of which were reduced by prior methotrexate treatment. The observation that the depletion of circulating leucocytes reduces both inflammatory cell accumulation and oedema formation suggests that these two processes are closely linked. In contrast treatment of animals with the anti-complementary agent K76COONa blocked leucocyte accumulation but had no effect on oedema formation indicating the two processes can occur independently. This conflicting data suggests that the association between leucocyte accumulation and oedema formation is complex.

Animals↗
PubMed1985

Studies into the influence of carrageenan-induced inflammation on articular cartilage degradation using implantation into air pouches.

We describe a novel system for examining the degradation of articular cartilage in vivo. Implantation of rat femoral head cartilage into six day old subcutaneous air pouches allows the examination of the degradation of cartilage in contact with a synovial lining-like structure. Femoral head cartilage was removed 1, 2 or 3 weeks after implantation and the proteoglycan content measured using 1,9-dimethyl methylene blue. Chondrocyte viability was confirmed using 35S sulphate incorporation. Increasing proteoglycan loss was observed over 3 weeks. Loss was similar in transplants between inbred and between outbred animals, suggesting that allograft rejection did not contribute significantly. Introduction of the irritant carrageenan into pouches produced a massive and prolonged inflammatory response characterized by exudation of leucocyte-rich fluid. Induction of inflammation with carrageenan did not alter the profile of proteoglycan loss from whole, minced, live or dead cartilage, as compared to that seen in non-inflamed pouches. These results indicate that when the relationship between articular cartilage and its normal tissue surroundings is disturbed, rapid proteoglycan loss may occur. The conditions induced by carrageenan inflammation have, in comparison, little or no effect on cartilage degradation. This raises the possibility that the direct effects of inflammatory products are of relatively minor importance to cartilage destruction in human arthritis.

Animals↗
PubMed1985

The immune response to pertussis in the 6-day air pouch: a model of chronic synovitis.

We have developed a model of prolonged immunological inflammation in the rat which has a structural resemblance to the synovial changes in rheumatoid arthritis. Pertussis vaccine was injected into 6-day-old subcutaneous air pouches in animals previously sensitized with pertussis vaccine. The resulting inflammatory response persisted up to 30 days. Examination of exudates showed a wave of polymorphonuclear leucocytes over a 13-day period followed by a mononuclear cell predominance up to 30 days. Histologically, an early polymorphonuclear cell infiltration was followed by the formation of a lining layer of large eosinophilic mononuclear cells, together with deep collections of lymphocytes and plasma cells. Concentrations of the acute-phase reactant alpha 1-glycoprotein, in both serum and exudate, peaked at 3 days. This suggests that the local production of interleukin I in this type of tissue reaction is more closely related to the acute inflammatory phase than to more chronic interactions between monocyte derived cells and lymphocytes.

Air↗
PubMed1984

The frequency of matching sequences in DNA.

Equations are presented which allow prediction of the number of direct or indirect matching sequences in DNA. Predicted match frequencies can be calculated for any match length, DNA strand length and DNA base composition, assuming only that the DNA sequence is random. The effect of varying these parameters is described, and match frequency is related to the total frequency of repeats. Equations were verified by computer search of randomly generated DNA sequences. A group of published DNA sequences was searched for matches and the results compared to the calculated predictions for random DNA. In general, natural DNA was found to be similar to random DNA with respect to frequency of matching sequences.

Base Composition↗
PubMed1984

The effect of therapeutic agents on cartilage degradation in-vivo.

Implantation of minced autologous cartilage into inflamed air pouches in mice allows the study of therapeutic agents on both the inflammatory process and cartilage degradation. Non-steroidal anti-inflammatory agents were found to reduce cell accumulation in response to carrageenan, but were unable to prevent proteoglycan loss from cartilage. In contrast, D-penicillamine had no effect on the inflammatory process but significantly reduced proteoglycan loss. Our findings suggest that the autologous cartilage transplantation model in the mouse may be useful for studying novel anti-arthritic agents.

Animals↗
PubMed1984

Effects of local administration of hydrocortisone on cartilage degradation in vivo.

The effect of corticosteroid on autologous minced cartilage transplanted into facsimile synovial cavities has been studied. The soluble form of hydrocortisone, as the sodium succinate, reduced proteoglycan loss from cartilage in a dose-dependent manner. In contrast, insoluble hydrocortisone acetate, if given directly into the cartilage-containing cavity, enhanced proteoglycan loss. Injection of the same dose of drug into the inflamed lining tissue reversed this effect. These findings suggest that intra-articular steroid injection may enhance cartilage damage if insoluble preparations are used, but that this may be overcome by injecting into the inflamed lining tissue rather than into the cavity itself.

Air↗
PubMed1984

Studies into the effects of the iron chelator desferrioxamine on the inflammatory process.

We have examined the effect of the iron chelating agent, desferrioxamine on different models of acute inflammation initiated by the irritants carrageenan or calcium pyrophosphate crystals. Depending on the dose of drug used and the time at which the lesion is examined both pro- and anti-inflammatory effects were observed as judged by measurement of leucocyte accumulation and oedema formation. The anti-inflammatory effects of desferrioxamine were supported by a decrease in concentration of the acute phase reactant alpha 1 glycoprotein. Our findings suggest that iron has a complicated relationship with the inflammatory process.

Animals↗
PubMed1983

Three new strains of infectious pancreatic necrosis virus isolated in Canada.

Three new samples of infectious pancreatic necrosis virus (IPNV) isolated in Canada were compared with known serotypes by phenotypic properties, immunofluorescence, and protein and RNA molecular weights. The three new isolates were each found to be unique by these parameters. The most convincing physical difference used to distinguish the new isolates from known serotypes was their RNA molecular weights. Thus, the new CB, NASRC, and Char isolates of IPNV represent three new strains of the virus.

Animals↗
PubMed1980

Coming of age.

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Aged↗
PubMed1979

Doctors and the media.

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Attitude of Health Personnel↗
PubMed1979

Comparison of EC broth and medium A-1 for the recovery of Escherichia coli from frozen shucked snow crab.

Two variations of the multiple-tube fermentation technique were used to enumerate fecal coliforms in commercially processed, frozen crab meat. These were the EC confirmation test and a more rapid method that requires medium A-1. The method with medium A-1 was more specific than the EC confirmation test for detecting Escherichia coli type 1. E. coli was isolated from 84% of the positive medium A-1 tubes, whereas it was isolated from only 64% of the positive tubes of EC broth. When samples of crab meat were inoculated with known amounts of E. coli, better estimates of the known numbers were obtained by the medium A-1 method. Several species of nonfecal coliforms were isolated from cultures in EC broth. These belonged to the genera Klebsiella, Citrobacter, Enterobacter, and Serratia. Apparently these strains were naturally adapted to growth at an elevated temperature because the majority were able to grow at 44.5 degrees C when retested in EC broth. Fewer species of nonfecal coliforms were isolated from medium A-1. Those that were isolated belonged to the genera Citrobacter and Enterobacter.

Brachyura↗