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Biomedical subjects

D J Shearman

Publications and source records attributed to D J Shearman.

At least 109 records · Page 6Linked to original sources
PubMed1973

Studies on the quantitation of immunoglobulin in human intestinal secretions.

There is increasing evidence for the importance of the secretory immune system in the gut. In studies of local antibody production it is important to have satisfactory methods for measuring immunoglobulin concentrations and to be aware of the errors which may occur. Studies on immunoglobulin measurement in intestinal secretion by the radial immunodiffusion method are reported, showing the effects of proteolytic digestion, IgA molecular size, and sampling and storage conditions. Because of the presence of monomeric IgA in addition to secretory IgA, there is no satisfactory standard for IgA in gastrointestinal secretions, and only semi-quantitative results can be given. With radial immunodiffusion, IgG and IgM when subjected to tryptic digestion, and IgA when subjected to peptic digestion, may be overestimated because of the presence of fragments of immunoglobulins. In addition, pepsin rapidly destroys IgM and IgG. Both IgM and IgG are unstable in storage. The findings suggest that immunoglobulin concentration measurements in small intestinal aspirates should be interpreted with caution. These problems are also relevant to the detection of specific antibodies in gastrointestinal secretions.

Chromatography, Gel↗
PubMed1972

Intestinal bacterial flora and bile salt studies in hypogammaglobulinaemia.

Five patients with adult acquired hypogammaglobulinaemia, four of whom were achlorhydric, were studied. Jejunal bacterial counts were much higher than those in a control group of acid secretors, but were similar to those in a control group of patients with pernicious anaemia; Giardia lamblia were isolated from the jejunal content of all patients with hypogammaglobulinaemia. The concentration of conjugated bile acids in the fasting state was lower in hypogammaglobulinaemia than in pernicious anaemia, but in the two hypogammaglobulinaemic patients with steatorrhoea there was a normal bile salt response to a fatty meal.

Adult↗
PubMed1972

Bacterial agglutination studies with secretory IgA prepared from human gastrointestinal secretions and colostrum.

The function of human purified colostral and gastrointestinal IgA has been studied by its ability to agglutinate common gastrointestinal organisms. Agglutinating activity was unaffected by trypsin or acid but it was abolished rapidly by pepsin. Both colostral and gastrointestinal IgA agglutinated a wide range of enteric organisms. Variations in this activity occurred between different individuals, and between different gastrointestinal sites in the same individual. In preliminary studies, saliva and IgA prepared from gastric and jejunal secretions in patients with pernicious anaemia showed a more uniform agglutination pattern than IgA prepared from the same sites in other patients. The agglutinin activity of IgA prepared from a particular site may be determined by the bacterial flora at that site. Agglutination methods for assessing the function of gastrointestinal antibody may be of value in the study of the possible roles of antibodies in inflammatory bowel disease.

Agglutination Tests↗