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Biomedical subjects

W R Burnham

Publications and source records attributed to W R Burnham.

At least 37 records · Page 2Linked to original sources
PubMed1994

Reversible jaundice in primary biliary cirrhosis due to hyperthyroidism.

A patient with primary biliary cirrhosis had a dramatic deterioration in liver function with jaundice over 2 months as a result of development of Graves' disease. Clinical examination and radiological and cardiovascular investigations excluded heart failure and biliary obstruction as the cause of this deterioration. The patient's jaundice entirely reversed with treatment of hyperthyroidism, with bilirubin levels decreasing from 244 to 16 mumol/L (14.35 to 0.94 mg/dL). Deterioration in liver function in a patient with primary biliary cirrhosis as a result of hyperthyroidism has not previously been described.

Bilirubin↗
PubMed1993

The effect of beta-adrenoreceptor agonists and antagonists on fructose absorption in man.

To explore the effect of beta-adrenoreceptor stimulation and blockade on the extraction of monosaccharide from the upper gut, we first established the malabsorption threshold in 26 normal volunteers using a series of test meals containing varying proportions of fructose and glucose. Incomplete small intestinal extraction and consequent arrival of carbohydrate into the caecum was identified by a rise in exhaled breath hydrogen concentration. The malabsorption threshold varied between individuals from 30 to 80 g fructose (median 40 g) but was reproducible within individuals, with 90% agreement of repeat studies. The malabsorption threshold for an individual was unrelated to body height (tau = 0.007, P > 0.05) or weight (tau = 0.003, P > 0.05) but correlated closely with time to onset of the breath hydrogen rise of a standard meal (tau = 0.70, P < 0.001). Administration of the beta-adrenoreceptor antagonist propranolol (160 mg) reduced the quantity of fructose required to exceed the malabsorption threshold from 45, 30-60 (median and range) to 40, 30-50 g (P = 0.03); administration of the beta-adrenoreceptor agonist isoprenaline (0.015 micrograms.kg/min) increased the quantity of fructose required to exceed the malabsorption threshold by 10 g (55 (50-90) g; P < 0.02). The effect of both drugs correlated closely with their transit effect (tau = 0.79, P < 0.01). A beta-adrenoreceptor mediated pathway thus appears to be capable of influencing the extraction of monosaccharide from the small intestine in normal subjects both under resting and stimulated conditions, probably acting via an effect on upper gastrointestinal motility.

Adrenergic beta-Agonists↗
PubMed1992

Controlled trial of endoscopic injection treatment for bleeding from peptic ulcers with visible vessels.

Controlled trials have shown that bleeding peptic ulcers can be successfully treated by endoscopy and injection of adrenaline, with or without sclerosant. However, these trials have been done in major research centres, and endoscopic treatment of upper gastrointestinal bleeding has not yet become routine in general hospitals. We have done a prospective, randomised, controlled trial of injection treatment for bleeding peptic ulcers in a district general hospital. Between April, 1989, and June, 1991, all patients with acute upper gastrointestinal bleeding (n = 555) underwent endoscopy by an experienced endoscopist within 24 h of admission. 98 patients were found to have an ulcer with a visible vessel, of whom 93 were randomised to injection (n = 48) or standard treatment alone (n = 45). Injection treatment consisted of 1-2 ml of 1 in 10,000 adrenaline injected at four to six sites around the ulcer. Adrenaline and 5% ethanolamine oleate (1-2 ml) were then injected directly into the vessel. The medical team managing the patient was unaware of the endoscopic treatment given. The two groups were similar for age, initial haemoglobin concentration, shock, and ulcer site. Rebleeding (injected 8 [16.7%] vs control 21 [46.7%], p = 0.011) was significantly reduced in treated patients. The treated group also had lower mortality (4 [8.3%] vs 9 [20%]), requirement for surgery (4 [8.3%] vs 8 [17.8%]), and mean blood-transfusion requirement (5 vs 7.5 units). Endoscopic injection treatment in our patients significantly reduced rebleeding rate and may have other benefits. This cheap and widely applicable treatment can be used routinely in the management of patients with bleeding peptic ulcers who are at high risk of rebleeding.

Adolescent↗
PubMed1992

The effect of alpha-1-adrenoreceptor agonist and antagonist administration on human upper gastrointestinal transit and motility.

To explore the role of alpha-1-adrenoreceptor-mediated pathways on human upper gut motor function in vivo, we studied the effects of the alpha-1-agonist phenylephrine and the alpha-1-antagonist thymoxamine on oro-caecal transit and antroduodenal motor activity. Transit was measured using a standard exhaled-breath hydrogen method, and motility was measured by intraluminal manometry. Oro-caecal transit was unaffected by 80 mg thymoxamine [median 63 min (range 35-164 min) vs. control, 65 min (range 30-155 min), P greater than 0.1]. However, phenylephrine (2.4 micrograms/kg/min) consistently delayed oro-caecal transit time to 103 min (50-215 min), P greater than 0.005. Co-administration of thymoxamine abolished this phenylephrine-induced delay. The mean amplitude of antral postprandial contractions was reduced by phenylephrine from 29 (13-37) to 10 (3-13) mmHg (P less than 0.02). In contrast, neither the pattern nor the mean inter-contraction interval was altered. Responses to phenylephrine in the duodenum were similar to those in the antrum, with reduction in amplitude from 12 (3-18) to 6 (5-13) mmHg without alteration in the pattern or interval between contractions. Nutrient transit through the upper gut can thus be inhibited via activation of an alpha-1-adrenoreceptor-mediated pathway. Failure of alpha-1-antagonist administration to alter oro-caecal transit suggests that this pathway is not tonically active, and it is therefore unlikely to play a major role in nutrient passage under normal circumstances.

Adrenergic alpha-Agonists↗
PubMed1992

Modulation of human upper intestinal nutrient transit by a beta adrenoreceptor mediated pathway.

To explore the role played by beta adrenoreceptor mediated pathways on human upper gut function a series of studies were conducted into the effects of beta adrenoreceptor agonists and antagonists on orocaecal and duodenocaecal transit and on antral and duodenal motor activity. Under control conditions orocaecal transit was consistent within individuals (mean coefficient of variation (18.0%) but varied widely between individuals (median transit 63 minutes, range 33-164). Prior administration of the non-selective beta adrenergic antagonist propranolol consistently hastened orocaecal transit (median transit 51:25-93, v control p < 0.005). The selective beta-1 antagonist, atenolol, also hastened transit (median transit 50:35-93 minutes, v control p < 0.01). The magnitude of an individual's response to beta blockade correlated closely with the orocaecal transit (Tau = 0.54, p < 0.01). Duodenocaecal transit was also hastened by propranolol from control values of 66:45-107 minutes to 50:16-62 minutes, p < 0.025). In contrast neither duodenal nor antral motility were consistently altered by beta blockade. The beta adrenoreceptor agonist, isoprenaline, delayed both orocaecal transient (97:55-178 minutes, v control p < 0.005) and also duodenocaecal transit (160:45-215 minutes, v 73:40-133) (p < 0.025). Isoprenaline also reduced antral motility by an effect which appeared to occur predominantly through a reduction in contraction amplitude (from a median amplitude of 27:5.39 mm Hg to 14:3-24 mm Hg, p < 0.03) rather than an effect on the interval between contractions. No effect on either amplitude or frequency of duodenal motor activity was observed. A beta adrenoreceptor mediated pathway thus appears to exert a biologically relevant effect on gut function not only under conditions of sympathetic stimulation, but also at rest when a basal beta adrenergic tone appears to influence the speed of nutrient transit through the human upper gut.

Adult↗
PubMed1990

Short bowel syndrome.

Nine patients with short bowel syndrome and high intestinal output received octreotide either intravenously (50-100 micrograms t.i.d.) or subcutaneously (100 micrograms b.i.d.) on 2 test days. In the 6 patients with net secretory output, there was a reduction in mean daily intestinal output of 0.5-5.0 kg; total daily intestinal output of sodium and potassium was also reduced significantly. Of the 3 patients with a net absorptive state, there was a worsening of output in 2 and no improvement occurred in the other. Two patients with net secretory output received long-term octreotide therapy, allowing a reduction in daily intravenous fluid intake of 1.0-1.5 litres.

Administration, Oral↗
PubMed1989

Octreotide (a somatostatin analogue) improves the quality of life in some patients with a short intestine.

Six patients with short intestine (jejunal length 25-70 cm) on long-term parenteral nutrition, needing 4-5 L of intravenous fluid daily, were given octreotide (a somatostatin analogue, SMS 201-995) to investigate whether it would reduce beneficially their secretory diarrhoea (3.6-6.9 kg/day). They consumed the same diet for 2 control days, followed by 2 test days. Octreotide was given intravenously, initially in a dose of 50 micrograms b.d. through the central feeding line. There was a significant reduction of daily stomal output (0.5-5.0 kg) and daily sodium and potassium output; however there was no significant change in energy absorption. The response to octreotide was greatest in those patients who absorbed least nutrients. A dose increase to 100 micrograms t.d.s. gave no further measurable benefit though the patients found it smoothed-out the post-prandial rise in stomal output. Two patients were continued on long-term octreotide therapy, which allowed for a daily reduction in intravenous fluid of 1 and 1.5 L. Octreotide's anti-secretory effect was found to have been maintained when it was retested in one patient after a year of continuous therapy.

Diarrhea↗
PubMed1989

Perturbation of upper gastrointestinal transit and antroduodenal motility by experimentally applied stress: the role of beta-adrenoreceptor mediated pathways.

A series of three experiments were performed on healthy adult volunteers to investigate the possible role played by beta-adrenoreceptor mediated pathways in the disturbance of human upper intestinal motor function by hand immersion in cold water. In the first experiment, (an extended pilot study on one individual), orocaecal transit of a standard meal was measured on 36 occasions with and without cold water stimulation and with and without a series of alpha and beta blocking drugs. Cold water stimulation consistently delayed transit in this individual, an effect which was attenuated by prior beta-blockade. In a double blind trial of the effect of beta-blocker atenolol v placebo on transit in nine individuals, a consistent reduction in the cold water induced transit delay was observed (p less than 0.01) independent of any direct effect of beta-blockade. In the third experiment seven individuals underwent repeated studies of antroduodenal pressure activity comparing the effects of cold and warm water stimulation with and without beta blockade to determine whether the observed transit effect could be related to an action on gastrointestinal motility. Cold water stimulation reduced antroduodenal motility, but no consistent effects of previous beta blockade were noted. These studies indicate the presence of a beta-adrenoreceptor mediated pathway in the cold water induced delay of orocaecal transit but not in the inhibition of gastroduodenal motility. Further studies are indicated to determine the site and mode of action of this transit effect more precisely.

Adolescent↗
PubMed1988

Effect of codeine and loperamide on upper intestinal transit and absorption in normal subjects and patients with postvagotomy diarrhoea.

Patients with chronic severe diarrhoea after truncal vagotomy and pyloroplasty are often difficult to treat using conventional antidiarrhoeal drugs and remain severely disabled. We examined the effect of two drugs, codeine phosphate and loperamide, on upper intestinal transit and carbohydrate absorption, measured non-invasively by serial exhaled breath hydrogen monitoring, in patients with postvagotomy diarrhoea who had previously failed to gain relief from drug therapy. Orocaecal transit was consistently faster in these patients than a group of controls and was associated with malabsorption of glucose. Codeine phosphate 60 mg significantly delayed transit in patients and controls and was associated with a reduction in glucose malabsorption and improvement in symptoms. Loperamide also delayed transit and improved symptoms, but the doses required for this effect (12-24 mg) were higher than usually considered necessary in secretory diarrhoea. These studies indicate that rapid intestinal nutrient transit and associated malabsorption is a factor in the development of diarrhoea postvagotomy and that symptomatic relief can be achieved in most patients by more rational use of existing drugs.

Adult↗
PubMed1987

Action of centrally mediated autonomic stimulation on human upper gastrointestinal transit: a comparative study of two stimuli.

Two well established experimental stressors, hand immersion in cold water, and mental stimulation with dichotomous listening, were applied to 37 normal subjects after the ingestion of a standard meal. Orocaecal transit was measured by serial exhaled breath hydrogen sampling. Cold water significantly delayed transit compared with warm water control (warm water 71.8 +/- 3.6 mins v cold water 93.2 +/- 5.7 mins p less than 0.01), with significant rises in blood pressure pulse rate perceived discomfort and plasma catecholamines. In contrast mental stimulation was unaccompanied by any change in transit (control; 67.4 +/- 4.7 v test 64.3 +/- 5.3 mins p greater than 0.1) despite a significant rise in pulse rate, skin conductance and plasma catecholamines. Repeated cold water immersion studies in eight individuals produced consistent orocaecal transit and autonomic responses, whereas mental stimulation showed reduced autonomic responses on repeat testing, suggesting that tolerance to the stimulus had occurred. The results of these studies show stimulus specific gastrointestinal response patterns to autonomic stimuli, and appear to have important implications for the design of future studies of human gastrointestinal autonomic physiology and for the investigation of patients with stress related gut dysfunction.

Acoustic Stimulation↗
PubMed1986

Controlled trial of small bipolar probe in bleeding peptic ulcers.

204 of 460 patients with upper gastrointestinal bleeding admitted to a busy district hospital were found to be bleeding from peptic ulcers or to have signs of recent haemorrhage at endoscopy within 24 h of admission. To determine if the small bipolar probe could stop bleeding or rebleeding, patients were allocated to electrocoagulation (101) or not (103); other aspects of treatment were identical. Groups were stratified by ulcer site to give similar numbers in each. To allow for differences in sex, age, initial haemoglobin, presence of other diseases, and shock, data were analysed by logistic regression. Fewer patients in the treated group (17) continued to bleed or rebled compared with controls (34). Rebleeding and mortality rates in the treated group were higher early in the trial, suggesting the need for experience in application of the probe. Further improvements in technology and technique may result in significant reductions in mortality.

Clinical Trials as Topic↗
PubMed1986

In vitro and clinical studies on intravenous feeding mixtures comprising fat emulsion, amino acid and electrolytes.

This paper describes the effect of the amino acid mixture Freamine II on the physical stability of Intralipid fat emulsion. The amino acid-fat emulsion mixture was also administered to patients requiring intravenous nutrition and its clinical and biochemical effects were assessed. The amino acid-fat emulsion mixture was stable on storage for 48 hours as judged by flocculation and particle growth measurements made in the presence of 20 mmol/1 monovalent cations at 2 mmol/1 diavalent cations. Long-term storage of mixtures containing Freamine II is not recommended because of an interaction between the emulsifier and the amino acids. In a small open trial patients maintained their serum albumin concentrations. There was no evidence of impaired pulmonary function even in those subjects with impaired fat clearance.

Journal Article↗