Biomedical subjects

W J Fitzpatrick

Publications and source records attributed to W J Fitzpatrick.

6 recordsLinked to original sources

PubMed1987

Bile acid binding to dietary casein: a study in vitro and in vivo.

1. Studies were carried out in vitro using an ultracentrifugation method to quantify bile acid binding to the different components of a Lundh test meal, and to determine what factors influence bile acid binding to one of the components (casein). We validated the ultracentrifugation method by showing good agreement with the equilibrium dialysis method. Studies were carried out in vivo on jejunal aspirate from 10 ileal resection patients in order to determine whether bile acid binding to casein could be demonstrated, and whether this influenced aqueous-phase bile acid and fatty acid concentrations. 2. In vitro, the Lundh test meal was found to adsorb bile acid. The protein content of the meal (casein) alone accounted for this binding, which was abolished by use of casein hydrolysate. The binding to casein was a saturable process. Both binding affinity and binding capacity were significantly greater for taurocholate at pH 4.5 than at pH 6.5, and for dihydroxylated than for trihydroxylated bile acid, suggesting that hydrophobic bonding was involved. 3. In vivo, jejunal samples aspirated at pH greater than 6 from 10 ileal resection patients showed 25% binding of bile acid to protein. On substitution of amino acids for casein, mean binding was reduced to 16% (P less than 0.05), residual binding being attributed to endogenous protein. This was associated with an increase in fatty acid solubilization from 28% to 60% (P less than 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1986

Ileal resection: effect of cimetidine and taurine on intrajejunal bile acid precipitation and lipid solubilisation.

We have investigated whether pH-dependent bile acid precipitation limits lipid solubilisation after ileal resection, and whether treatment with cimetidine, or taurine improves solubilisation. Nine ileal resection patients were treated with placebo, cimetidine and taurine in random order for two weeks each. Upper jejunal content was aspirated and pooled according to pH for three hours after a standard Lundh test meal. On placebo, 50% of the bile acids were precipitated at pH less than 5, compared with only 26% at pH greater than 6, whilst aqueous-phase lipid concentration tended to be lower at pH less than 5 than at pH greater than 6 (5.1 vs 8.2 mmol/l). On cimetidine mean pH rose, particularly during the third hour (6.6 vs 5.8, p less than 0.05), associated with a reduction in bile acid precipitation (13.9 vs 33.1%, p less than 0.05), and an increase in aqueous-phase lipid concentration (10.4 vs 6.6 mmol/l, p less than 0.05). On taurine, the proportion of taurine conjugated bile acids increased (67 vs 22%, p less than 0.01), but there was no significant change in bile acid precipitation or lipid solubilisation. Lower jejunal samples were aspirated similarly from five of these patients on no treatment, and all were at pH greater than 6; apparent 'precipitation' was reduced (16.4 vs 28.1%), but lipid solubilisation did not improve. These findings suggest that pH dependent bile acid precipitation can limit lipid solubilisation within the jejunum after ileal resection, and that these effects can be reduced by cimetidine but not by taurine. Cimetidine may have a role in ileal resection patients with severe steatorrhoea unresponsive to dietary fat restriction.

Adult↗

PubMed1984

Hyperthyroidism and acute bronchial asthma.

Asthma may be very mild, at times hard to diagnose; beta blockade should be used only with great caution. An asthmatic who becomes thyrotoxic should be closely monitored for deterioration of the asthma.

Adult↗

PubMed1984

Effect of intrajejunal acidity on lipid digestion and aqueous solubilisation of bile acids and lipids in health, using a new simple method of lipase inactivation.

We have investigated whether acid-mediated bile acid precipitation, pancreatic enzyme inactivation, and fatty acid partitioning occur in health when intraluminal pH falls below 5. In order to assess lipolysis and aqueous solubilisation of lipid, we first developed a new technique for inactivating lipase in jejunal aspirate (acid inactivation), and showed it to be more effective and simpler than the established technique (heat inactivation). We then studied 14 healthy subjects, aspirating jejunal content for three hours after a liquid meal, and pooling according to pH. Eighteen per cent of the total aspirate was collected at pH less than 5 compared with 56% at pH greater than 6 (p less than 0.01). Forty eight per cent of the bile acids were precipitated at pH less than 5 compared with 18% at pH greater than 6 (p less than 0.01), leading to a reduction in aqueous phase bile acid concentration at low pH (2.1 mmol/l at pH less than 5 vs 5.8 mmol/l at pH greater than 6, p less than 0.01). Lipase activity was reduced at low pH (133 IU/l at pH less than 5 vs 182 IU/l at pH greater than 6, p less than 0.01), leading to reduced lipolysis at low pH (14% at pH less than 5 vs 32% at pH greater than 6, p less than 0.01). Aqueous phase lipid concentration was reduced at low pH (3.5 mmol/l at pH less than 5 vs 12.5 mmol/l at pH greater than 6, p less than 0.01). This reduction was less dependent on bile acid precipitation than on lipase inactivation and fatty acid partitioning. We conclude that intraluminal acidity influences aqueous solubilisation of bile acids and lipid in health.

Adult↗

PubMed1984

Effect of intrajejunal acidity on aqueous phase bile acid and lipid concentrations in pancreatic steatorrhoea due to cystic fibrosis.

We have investigated whether jejunal hyperacidity leads to bile acid precipitation and thus limits lipid solubilisation in patients with pancreatic steatorrhoea. Jejunal contents from 12 adults with steatorrhoea due to cystic fibrosis were aspirated for three hours after a liquid test meal, and pooled according to their pH. Thirty eight per cent of the total aspirate was collected at pH less than 5 in cystic fibrosis, compared with 18% in healthy controls (p less than 0.05). Forty six per cent of the bile acids were precipitated at pH less than 5, compared with 15% at pH greater than 6 (p less than 0.01), leading to reduced aqueous phase bile acid concentration at low pH (4.7 mmol/l at pH less than 5 vs 12.5 mmol/l at pH greater than 6, p less than 0.01). Aqueous phase lipid concentrations were reduced at low pH (5.6 mmol/l at pH less than 5 vs 10.2 mmol/l at pH greater than 6, p less than 0.01). Lipolysis and total fatty acid concentrations were greatly reduced and did not vary with pH. We therefore conclude that jejunal hyperacidity leads to bile acid precipitation in pancreatic steatorrhoea due to cystic fibrosis, and imposes a further limitation on lipid solubilisation over that of lipase deficiency.

Adult↗

PubMed1982

Bedtime cimetidine maintenance treatment: optimum dose and effect on subsequent natural history of duodenal ulcer.

Sixty patients, whose duodenal ulcers had healed endoscopically after six weeks of treatment with cimetidine 1 g/day in divided doses, were treated with maintenance cimetidine 800 mg at bedtime for six months. Eighteen relapsed endoscopically (30%). Of the 42 still in remission, 36 then completed a six month double-blind comparison of bedtime cimetidine 400 mg and placebo. Twelve of the 19 (63%) cimetidine-treated patients and 10 of 17 (59%) placebo-treated patients relapsed within six weeks (NS). This high relapse rate on cimetidine contrasts with our earlier trial, in which the six week relapse rate was only two out of 21 (10%) on bedtime cimetidine 800 mg and 16 out of 24 (66%) on placebo (P less than 0.0005). Apart from the difference in the dose of cimetidine, both our trials used the same experimental protocol during the double-blind part of the trial. In the earlier trial, however, there was no period of pretreatment with maintenance cimetidine as in the present trial. The pattern of placebo relapse was similar in both trials. We conclude that bedtime cimetidine maintenance treatment does not alter the long-term natural history of duodenal ulcer once it has been withdrawn; and that either tolerance to cimetidine develops during long-term maintenance treatment, or that bedtime cimetidine maintenance treatment in the conventional dose of 400 mg is not as effective as 800 mg in prevention of endoscopic relapse, although it does reduce symptoms.

Cimetidine↗