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Biomedical subjects

W D Mitchell

Publications and source records attributed to W D Mitchell.

At least 55 records · Page 3Linked to original sources
PubMed1975

Bile acids and colonic motility in the rabbit and the human.

Colonic motor activity was initiated by infusions of bile salts into the caecum or rectum of the anaesthetized rabbit. Primary bile acids were examined proximally and distally in the colon and elicited marked motor responses. Sinc dihydroxy bile acids are known to be potent inhibitors of electrolyte and water absorption in the colon, the secondary bile acid deoxycholic acid, the dihydroxyl compound most related to cholic acid which is the main bile acid in the rabbit, was examined distally and was also active, but to a lesser extent than cholic acid conjugates in this species. In man, a relationship was found between the faecal bile acid excretion and colonic motility: the introduction of bile acids directly into the human sigmoid colon and rectum also stimulated colonic motility. In man, the dihydroxy compound chenodeoxycholic acid was slightly more active than conjugates of cholic acid.

Animals↗
PubMed1974

Action of different bran preparations on colonic function.

Two different types of commercially available bran were studied. One of these was composed of flake-like particles (coarse bran) whereas the other had smaller, finer particles with a floury component (fine bran). The effectiveness of the two preparations in lowering intraluminal pressure and decreasing transit time in patients with constipation and diverticular disease was assessed. Only coarse bran promoted changes at the dose used. The physical properties of the brans were examined in an effort to explain their differing effects. It is concluded that water-holding capacity, upon which the beneficial effect of bran may depend, is a function of particle size. The greater water-holding capacity of coarse bran makes it preferable for the treatment of colonic disorders.

Constipation↗
PubMed1974

Intestinal streaming patterns in cholerrhoeic enteropathy and diverticular disease.

Streaming of gastrointestinal contents depends on the demonstration of differential rates of recovery of equal doses of two synchronously fed markers. There was no significant difference in the rate of throughput of polyethylene glycol (a liquid phase marker) and chromium sesquioxide (a solid phase marker) in healthy volunteers (n = 7) and hospital inpatients (n = 5) with normal bowel habit, so that streaming does not usually occur. In cholerrhoeic enteropathy (n = 5), however, the rate of throughput of polyethylene glycol was increased. In colonic diverticular disease (n = 7) the rate of throughput of polyethylene glycol was significantly lower. In cholerrhoeic enteropathy the liquid phase marker was excreted 1.5 times faster than the solid phase, but in the diverticular disease group the liquid phase was excreted 0.75 times more slowly than the solid phase marker. This may reflect the effects of colonic hypersegmentation on the relative distribution of the liquid and solid phases.

Adult↗
PubMed1973

Effects of dietary supplements of wheat bran and cellulose on faeces and bowel function.

In a study of bowel function in normal subjects wheat bran or cellulose was added to the diet for four weeks (16 g/day). Stool weight increased. Intestinal transit time did not significantly alter. Faecal bile acids did not increase but were diluted. It seems that the effect of these materials is to produce a bulky stool and that any symptomatic benefit they produce is secondary to this.

Adult↗
PubMed1973

The physical state of bile acids in the diarrhoeal stool of ileal dysfunction.

A method is described for the separation of a diarrhoeal stool into solid and liquid phases. The seven patients studied had varying degrees of ileal resection. Faecal bile acids were measured in supernatant and pellet. Freeze-dried pellet of the patients had significantly higher bile acid content than freeze-dried faeces of the eight controls (patients mean = 55.8 mg bile acids/g freeze-dried faeces; normals = 8.3 mg bile acids/g freeze-dried faeces; P < 0.005). The presence of bile acids in the supernatant of these patients is discussed with regard to the binding capacity of the dietary residue in the colon. The faecal excretion of bile acids throughout the day in three patients was studied using the centrifugation method.

Adult↗
PubMed1973

Bile acids in the diarrhoea of ileal resection.

Twenty individual diarrhoeal stools from three patients with ileal resection were centrifuged at 14 000 g for one hour at 10 degrees C to separate the stool into pellet and supernatant. Bile acids and electrolytes were measured in each phase. Relationships were examined between chenodeoxycholic acid and cholic acid in each phase and in toto to electrolyte and water loss. Chenodeoxycholic acid was associated with electrolyte and water loss whether present in solid or liquid phase. The association varied between individuals. The cholic acid content of the stool showed no association with electrolyte and water loss. It would appear that it is the total amount of chenodeoxycholic acid entering the colon, irrespective of its physical state, that is important in the diarrhoea of ileal dysfunction.

Adult↗