Search PubMed⌕ Search

Biomedical subjects

J A Gibson

Publications and source records attributed to J A Gibson.

At least 73 records · Page 4Linked to original sources
PubMed1976

The diarrhoeas.

Explore the source record for details and available documents.

Celiac Disease↗
PubMed1976

The role of the colon in urea metabolism in man.

1. The urea content of ileostomy effluent has been measured by the urease method as an indirect estimate of the urea concentration in the lumen of the normal ileum. 2. The plasma disappearance of intravenously administered[14C]urea was used to study intestinal urea breakdown. Normal subjects on high and low protein diets and patients with either excised (i.e. with ileostomies) or excluded colons were studied. 3. The 24 h intestinal urea breakdown was considerably greater than the quantity of urea estimated to be entering the colon from the ileum and across the colonic mucosa. 4. Intestinal urea breakdown increased with increase in dietary protein and decreased with, but was not abolished by, exclusion or excision of the colon. 5. Our results suggest that the colonic lumen is not the only site of intestinal ureolysis and that significant quantities of urea must be broken down either at a juxtamucosal site or in the ileum.

Body Weight↗
PubMed1976

Protein absorption and ammonia production: the effects of dietary protein and removal of the colon.

1. The effect of increasing dietary protein content on the amount of faecal nitrogen was measured in six normal subjects and five subjects without functioning colons (three with ileostomy and two with ileo-rectal anastomosis). 2. There was a significant inontent in the subjects without functioning colons. 3. In normal subjects with intact colons, faceal N content was found to be lower than that in subjects without colons, and furthermore there was no significant variation with diet. 4. The source of the increase in faecal N with increased dietary protein content in subjects without functioning colons is discussed and the significance of these findings in relation to the efficiency of protein absorption is considered.

Ammonia↗
PubMed1975

Ammonia and urea transport by the excluded human colon.

1. Ammonia and urea transport across the colonic mucosa was studied by a perfusion technique in four subjects with colonic exclusion for chronic hepatic encephalopathy. 2. Reduction of luminal pH inhibited net and unidirectional transport of ammonia from lumen to plasma, but net absorption from high luminal concentrations persisted at low pH. 3. Neither addition of urea to the perfusate nor intravenous infusion of urea produced a consistent increase in the colonic excretion of ammonia when ammonia-free solutions were perfused. 4. In one subject intravenous infusion of (15N)-ammonium chloride produced rapid labelling of colonic effluent ammonia and within 60 min the specific enrichments of ammonia in effluent and in arterial plasma were approximately equal. 5. During perfusion of nitrogen-free solutions, only small amounts of urea appeared in the effluent, suggesing limited permeability of the colonic mucosa to urea. 6. These results are discussed in relation to the equilibration of ammonia across the colonic mucosa by both ionic and non-ionic diffusion. The lack of evidence of 'juxtamucosal' (as opposed to luminal) ureolysis is in contrast to other observations on the intact colon. The possible reasons for and implications of this discrepancy are discussed.

Ammonia↗
PubMed1975

Comparison of the sensitivity of human embryo kidney cells, HeLa cells, and WI38 cells for the primary isolation of viruses from the eye.

A comparison has been made of the efficiency of human embryo kidney (HEK) cills, HeLa cells, and WI38 cells for the isolation of viruses from the eyes of patients suffering from acute conjunctivitis or keratoconjunctivitis. From a total of 99 specimens 21 adenoviruses (serotypes 3, 4, 7, 8, and 13) were isolated in HEK cells, eight (serotypes 3 and 8) in HeLa cells, and four (serotype 3) in WI38 cells. Of the ten herpes simplex viruses isolated nine were recovered in HEK cells, seven in WI38 cells, and none in HeLa cells. The combination of HeLa cells and WI38 cells is not considered an adequate alternative to the difficult-to-obtain HEK cells for the isolation of viruses from the eye.

Adenoviridae↗
PubMed1974

Effects of lactulose and other laxatives on ileal and colonic pH as measured by a radiotelemetry device.

Using a pH-sensitive radiotelemetering device the effect of lactulose on luminal pH in the ileum, colon, and rectum has been compared with that of two other laxative agents. Lactulose produced marked acidification of proximal colonic contents but this effect was not consistently maintained into the distal colon. Sodium sulphate acidified distal rather than proximal colonic contents. However, for a similar degree of laxation it was not possible to produce a significantly more uniform reduction of pH along the length of the colon by combining these laxatives compared with lactulose alone. Magnesium sulphate had little effect upon luminal pH except in the rectum where a significant rise occurred. These results are discussed in relation to both normal colonic physiology and to their possible relevance to the treatment of chronic hepatic encephalopathy by colonic acidification.

Adult↗