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Biomedical subjects

P Millard

Publications and source records attributed to P Millard.

45 records · Page 3Linked to original sources
PubMed1984

Glycosidic linkages of swede cell walls and their residues recovered from the terminal ileum of the pig.

The glycosidic linkage pattern of unfractionated swede cell walls was determined by methylation analysis. The main linkages in descending order of concentration were: (1----4)-linked glucose, (1----4)-linked xylose, terminal galactose, (1----4)-linked mannose, terminal arabinose and (1----2)-linked rhamnose. The major branch points were to the O-2 or O-3 atoms of xylose, O-4 of rhamnose and O-6 of glucose. The subsequent degradation of swede cell walls by passage through the small intestine of the pig was studied by quantitative methylation analysis of material recovered from animals cannulated 150 mm before the ileo-caecal junction. In addition to a substantial loss of uronic acid and phenolic material, the proportions of the different glycosidic linkages recovered from the digesta varied greatly from those of the parent material. Pectic polysaccharides had apparent digestibilities in the range of 0.60-0.75 while those of hemicellulosic components varied between 0.15 and 0.57. Glucose units linked 1----4 (with an apparent digestibility of 0.24) accounted for the greatest weight loss of neutral sugars from the cell wall, followed by terminal galactose, terminal arabinose and 2-linked arabinose.

Animals↗
PubMed1984

Modifications to swede (Brassica napus L.) anterior to the terminal ileum of pigs: some implications for the analysis of dietary fibre.

The degradation of a swede (Brassica napus L., cv. Danestone) diet anterior to the terminal ileum was studied in two pigs fitted with T-shaped cannulas 150 mm before the ileo-caecal junction. Digestibility was calculated with reference to chromic oxide and polyethylene glycol. In addition to the total loss of free glucose and fructose, there were substantial modifications to cell-wall material recovered in digesta. These included the apparent loss of 46-50% of uronic acid residues, 72-78% of phenolic material and 10-24% of cellulose initially present in the feed, and a partial solubilization of some hemicellulose components. Since 'fibre' recovered at the terminal ileum differed in a number of important respects from ingested fibre, a number of methods for the analysis of dietary fibre were examined to establish (1) the extent to which analysis of feed represented material recovered at the terminal ileum and (2) whether such methods could be applied directly to digesta samples. Results were compared with a complete analysis of water-soluble (620 g/kg dry matter) and water-insoluble (380 g/kg dry matter) fractions of feed. Chemical fractionation techniques gave more reliable quantitative estimates of fibre than in vitro enzymic digestion methods which overestimated fibre. Acid- and neutral-detergent methods both gave too low an estimate of fibre. As none of the methods could allow for the loss of components (particularly pectic polysaccharides) found by sampling at the terminal ileum, none gave an accurate qualitative or quantitative representation of fibre at this point in the gut. It is suggested that, as vegetable fibre recovered at the terminal ileum has already undergone partial hydrolysis, a more dynamic model of dietary fibre, in which the action of gut micro-organisms is considered, may be required to establish possible physiological roles of fibre or fibre components in the digestive tract. Recovery of digesta from sites of interest may be the only way of reliably estimating fibre or specific fibre components at different levels of the gut. This approach to dietary fibre may be impractical when applied directly to humans but the digestive tract of the pig may be a suitable alternative model.

Animal Feed↗
PubMed1980

Studies on the effects of cyclosporin A upon renal allograft rejection in the dog.

Dose and time response studies of the new immunosuppressive agent, cyclosporin A, have been performed in a dog renal allograft model. Rejection of a renal allograft only occurred in one of six dogs receiving 20 mg/kg/day continuously, but in 10 of 11 dogs receiving 10 mg/kg/day. Doses of 10 or 20 mg/kg/day given for 2 or 3 weeks delayed rejection, but rejection occurred in all animals when the drug was stopped. This suggests that the drug does not produce clonal deletion of the lymphocytes engaged in the immune reaction against the graft, but merely their suppression. The histological picture of rejection was markedly improved by therapeutic doses of cyclosporin A. No consistent histological or biochemical evidence for heptatoxicity or nephrotoxicity was found even in the higher doses tested. One fatal and four non-fatal infectious complications were seen in 29 dogs receiving doses of 5 mg/kg/day or higher.

Animals↗