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Biomedical subjects

A S McIntyre

Publications and source records attributed to A S McIntyre.

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

Double-blind crossover trial of metronidazole versus placebo in chronic unremitting pouchitis.

Metronidazole has been used to treat pouchitis, but there are no controlled data that show it is effective. Chronic unremitting pouchitis is a form of the disorder particularly difficult to manage. Diarrhea is the main symptom of pouchitis, which results from acute inflammation of the mucosa of an ileal reservoir. To test the hypothesis that metronidazole (400 mg thrice daily for seven days) is no better than placebo at reducing stool frequency in chronic unremitting pouchitis, a double-blind placebo-controlled crossover study has been performed. Thirteen patients who had undergone restorative proctocolectomy for ulcerative colitis were studied. The diagnosis of pouchitis was based on clinical, endoscopic, and histological criteria. At entry all patients had symptomatic pouchitis and were passing more than six stools/24 hr or had consistently bloody stools with at least four of six endoscopic criteria of mucosal inflammation. The median frequency of defecation decreased by 3 bowel actions/24 hr (conservative 95% confidence intervals 0-4/24 hr) on metronidazole but increased by a median of 1/24 hr on placebo. The difference between the median number of bowel motions, when treatment with metronidazole was compared to placebo, was 4 motions/24 hr (P < 0.05) in favor of metronidazole. There was no significant change in the endoscopic or histological grade of inflammation, in the serum C-reactive protein level, or symptomatic scores. In a parallel study, metronidazole did not alter stool frequency in asymptomatic patients without pouchitis who had endoscopically normal reservoirs (six polyposis, six colitis).(ABSTRACT TRUNCATED AT 250 WORDS)

C-Reactive Protein↗
PubMed1993

Audit of outcome of long-term enteral nutrition by percutaneous endoscopic gastrostomy.

Percutaneous endoscopic gastrostomy (PEG) is the preferred method for administration of long-term enteral tube feeding. However, most published studies describe only short-term follow-up in any detail. We report the long-term outcome and complication rate after PEG insertion in 49 patients (mean [SE] age 64 [2] years) whose mean length of PEG feeding was 175 days (range 30-560). Data were collected prospectively. PEG insertion was technically successful in all cases, with a procedure-related mortality of 2%. Early (< 30 days) mortality and morbidity were 8% and 22%, respectively. Of 45 patients surviving for more than 30 days, 76% were able to return home and 6 patients were eventually able to revert to oral feeding. There were 27 late complications: 2 site infections, 17 mechanical problems, and 8 episodes of gastrointestinal dysfunction. 51% of patients had no problems at all and 22% had 2 or more complications. 47% of complications required a hospital visit for resolution. Long-term enteral feeding by PEG was safe, effective, and had a low complication rate. Our patients were managed by a specialist nutrition team, a policy that may reduce the complication rate and hospital visits for patients being fed at home, and allow early discharge of dysphagic patients, thereby reducing costs.

Aged↗
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↗
PubMed1993

Prospective survey of investigations in outpatients referred with iron deficiency anaemia.

Recent evidence has suggested that colonic neoplasm may be missed in patients presenting with iron deficiency anaemia unless colonic investigations are performed on all patients even when an alternative cause has been found. This study prospectively surveyed 114 consecutive patients referred from family practitioners to an outpatient clinic for the investigation of iron deficiency anaemia to determine the diagnoses contributing to the anaemia, the usefulness of certain clinical features, and the role of colonic and other investigations in obtaining the diagnosis. Upper gastrointestinal lesions contributing to anaemia were identified in 45 patients while colonic lesions were found in 18. Twenty three patients had a non-gastrointestinal cause for anaemia and in 12 patients no cause was found. Only two patients were identified as having colonic neoplasia (a small adenomatous polyp in each case) coexisting with upper gastrointestinal lesions. Symptoms and signs had a sensitivity and specificity of upper gastrointestinal disease of 50% and 83% respectively, and 44% and 80% for colonic disease. Endoscopy had a high yield (42%) and duodenal biopsy identified coeliac disease in three patients (two were aged > 70 years) each of whom had normal folate values. Barium enema had a yield of 13%. All colonic carcinomas occurred in patients > 65 years. The coexistence of colonic cancer or large polyps with an upper gastrointestinal lesion identified at endoscopy was rare in outpatients referred from family practitioners. Clinical symptoms and signs were poor indicators of the investigations that will detect a cause for the anaemia. Endoscopy (with duodenal biopsy) should be performed on all patients. The yield from barium enema is so low in young patients that if an upper gastrointestinal cause is found and there are no clinical indicators it would seem unnecessary.

Adenoma↗
PubMed1993

A clinical audit of cardiopulmonary resuscitation.

The structure, process and outcome of cardiopulmonary resuscitation (CPR) at one hospital have been reviewed to determine where failings in the system could be improved, whether the existing training programme was adequate and well directed, and whether survival rates were reasonable. In the first seven months 143 reports were received; 49% of them were cardiac, 17% respiratory, and 24% mixed cardiorespiratory arrests. Overall, immediate survival was 43% of those with cardiorespiratory arrests. Seventy per cent of the immediate survivors were alive at 24 hours, and 69% of them survived to six weeks or beyond. The most important indicator for a successful outcome was the heart rhythm at the time of the resuscitation team's arrival, with 71% surviving from ventricular fibrillation, 20% surviving from apparent asystole, and only 9% surviving from electromechanical dissociation. No patient with the latter two rhythms survived to six weeks or left hospital. Neither the location or time of the arrest, nor the patient's age influenced the immediate survival. The audit revealed a need to improve telephone connections to the hospital switchboard, modify some equipment, and improve knowledge of the geography of the hospital site. Changes in emphasis in the training programme will alter the process of resuscitation. Outcome measures indicate that survival figures are comparable with published data, including recent data which act as a benchmark for quality control.

Cardiopulmonary Resuscitation↗
PubMed1992

Review article: adrenergic control of motor and secretory function in the gastrointestinal tract.

The role that the sympathetic nervous system plays in modulating physiological processes in the gastrointestinal tract is becoming clearer. It is now known that motor, secretomotor and vasomotor activity are all modulated independently by the system. Adrenoreceptor stimulation appears to reduce intestinal contraction (except at sphincters), both via alpha-receptors which inhibit neurotransmitter release and also by a direct beta-receptor mediated action on smooth muscle. There is also evidence for tonic activity in the beta-adrenergic pathway, since beta-antagonists tend to increase contraction pressures. In animals alpha-receptor-mediated pathways modulate fluid and electrolyte absorption, and alpha-adrenergic agonists enhance net absorption and reduce net secretion. In man there is also evidence for a beta-adrenergic pathway which controls secretomotor function. Carbohydrate absorption appears to be dependent on activity in a beta-adrenergic pathway, although this may be an indirect effect of changes in motor function. The time course of changes of both secretomotor and motor activity, induced by modulating sympathetic or adrenergic input, differ from the vascular changes indicating that the effects occur independently of each other. The gastrointestinal response to stressors is mediated, in part at least, by the sympathetic nervous system. Differences between individuals are likely to prove important. Since the sympathetic nervous system regulates gastrointestinal function both in the basal state and under stressful conditions, it will have effects on pathophysiological responses. Modification of such responses is likely to ameliorate symptoms, as has already been found for alpha-2-adrenergic agonists which have an antidiarrhoeal action.

Animals↗
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↗
PubMed1992

Fatal fulminant hepatic failure in a 'solvent abuser'.

The case of a 17 year old abuser of butane aerosols who developed fulminant hepatic failure after taking a proprietary engine or carburetor cleaner is described. Fatalities as a result of liver failure due to volatile hydrocarbons or solvents have not previously been reported. The likely toxins included isopropyl alcohol, methyl amyl alcohol, butylated hydroxytoluene as well as petroleum products, and evidence for their toxicity is reviewed. The possibility of increased susceptibility to hepatotoxins after enzyme induction by abuse of volatile agents is discussed. Hepatic dysfunction should be sought in patients who abuse solvents or volatile hydrocarbons and supportive measures instituted promptly when required.

Adolescent↗
PubMed1991

The practice of rectal examination.

Rectal (both digital and rigid sigmoidoscopic) examination is an important part of the clinical examination. The aim of this study was to find out the opinions of the patients to this routine examination at the time of referral by their general practitioner and during their first hospital interview. Assessment of the value for the rectal examination was also examined. We questioned 103 patients attending their second out-patient interview through a simple questionnaire. We discovered that patients considered awareness and explanation important: patients preferred to be told of the possibility of rectal examination prior to hospital consultation. Explanation of the method and reason was expected from hospital doctors. Formal consent was expected; informed verbal consent should be sufficient. Where logistically possible, a chaperone should always be present. Rectal examination would have facilitated the diagnosis in 47% of the patients examined. Thus, rectal examination should be performed on all patients where symptoms are referable to the lower gastrointestinal tract and where a possible diagnosis may be made or facilitated.

Adolescent↗
PubMed1990

Long-term parenteral nutrition: problems with venous access.

Long-term parenteral nutrition requires central venous access, often difficult in patients who have had several central venous catheterizations. Therapy may be complicated by thrombosis and sepsis which may further compromise central access. We report five cases illustrating such difficulties and suggest that these patients be referred early to specialist centres where experienced catheter insertion and management results in a greatly reduced incidence of complications.

Adult↗
PubMed1989

Motor responses of the upper esophageal sphincter and body to intraluminal acid.

1. It is known that contraction of the upper esophageal sphincter (UES) and secondary peristalsis protect the airway and clear the esophagus of refluxed gastric contents. However, the exact nature of the stimulus and the role of acid remain controversial. 2. Secondary peristalsis and UES responses were measured following the intraluminal infusion of 0.1 N hydrochloric acid and equiosmolar NaCl solutions in seven normal volunteers. The protocol consisted of three phases: infusion of increasing volumes (1, 3, 5 and 7 ml per min), infusion of a given volume (7 ml per min) at different stimulation sites and balloon distension. 3. At the proximal esophagus the UES response to both solutions was similar, rising from a basal resting pressure of 30 mmHg to 70 mmHg for both HCl (range 60-85 mmHg) and NaCl (55-85 mmHg). The magnitude of the response decreased as the distance from the UES increased. The level of response decreased to 40 mmHg for both NaCl and HCl (range 30-60 mmHg) at the distal esophagus. These responses were also volume dependent. When the solutions were infused at 7 ml/min into either the proximal or distal esophagus, the sphincter pressure increased with increased volume to 65 mmHg for HCl (range 50-85 mmHg) and 60 mmHg for NaCl (range 50-80 mmHg). Secondary peristalsis was also induced by the two solutions. The level of response again decreased as the distance from the UES increased. This response was also volume dependent. Esophageal distension by a balloon positioned 10 cm below the sphincter induced secondary peristalsis and sphincter response identical to those induced by the infusion of fluid. 4. These results indicate that the principal stimulus for recruitment of the esophageal motor clearance mechanism is intraluminal distension and not necessarily the pressure of intraluminal acid.

Adult↗
PubMed1988

Studies of the oesophageal clearance responses to intraluminal acid.

Contraction of the upper oesophageal sphincter combined with secondary peristalsis clears the oesophagus of refluxed gastric contents and protects the trachea, but the nature of these reflex stimuli remains controversial. Secondary peristaltic and sphincteric responses were measured during intraluminal infusion of 0.1 N hydrochloric acid and equiosmolar saline solutions in seven normal volunteers. Responses to a single volume infused at varying sites in the oesophagus and to progressively increasing volumes of test solution were measured. In addition oesophageal responses to similar degrees of distension induced by inflation of an intraluminal balloon were also recorded. The sphincteric responses to both stimuli were similar, decreasing in value with distance from the sphincter from values of 70 (68-85) mmHg (median (range] for HCl; and 70 (55-85) mmHg for NaCl at 5 cm below the sphincter to 40 (30-60) mmHg for both HCl and NaCl at 20 cm. As the volume of the solution infused into the proximal oesophagus was increased, the sphincter pressure also rose from a median basal value of 30 (25-50) mmHg to 40 (30-50) mmHg for HCl and NaCl after 1 ml, while after 7 ml infusion, the responses were greater, 65 (45-85) mmHg for HCl, and 60 (45-80) mmHg for NaCl. In the more distal oesophagus, responses were qualitatively similar but quantitatively smaller than proximally, being 30 (25-40) mmHg for HCl and 30 (25-50) mmHg for NaCl following 1 ml and 45 (40-55) mmHg for HCl and NaCl after 7 ml. Secondary peristalsis was also induced equally by both solutions and varied with volumes infused and site of infusion in a manner similar to the sphincter responses. After a 7 ml/min acid infusion 14 (1- 40) secondary contractions/three min were recorded at 5 cm and eight (2 - 18)/three min were recorded at 20 cm. Values for saline were similar, 13 (1- 38)/three min at 5 cm and eight (4 - 25)/three min at 20 cm. Oesophageal distension by a balloon positioned 10 cm below the sphincter induced identical clearance responses to those seen after similar volumes of either acid or saline infused at the same site. These results suggest that the principal stimulus for upper oesophageal clearance is intraluminal distension and do not support the idea that the oesophagus is pH sensitive.

Adult↗
PubMedDate not supplied

Palliative therapy of malignant esophageal stricture with the bipolar tumor probe and prosthetic tube.

Patients with malignant esophageal stricture and dysphagia were prospectively randomized to receive palliative therapy with the bipolar tumor probe (17) or prosthetic tube insertion (13). Both treatments gave good relief of dysphagia compared with pretreatment values on a dysphagia score, the results being statistically significant (p less than 0.005). However, there was no difference in the improvement achieved by one method compared with the other. The tumor probe was not difficult to use and complication rates were comparable. In the Atkinson tube group, two patients developed complications related to the position of the prosthesis and in three others food blocked the tube. Treatment with the tumor probe needed repeating at intervals (median, 28 days; range, 2 to 86 days) in all but four individuals to maintain palliation, with each patient needing a median of two treatments (range, 1 to 8). The probe may have advantages in very high esophageal lesions and may facilitate the treatment of tumor overgrowth or undergrowth of a tube. The prosthetic tube may give long-lasting relief of dysphagia and remains the treatment of choice for bronchopulmonary fistulas.

Adenocarcinoma↗
PubMedDate not supplied

The endoscopic appearance of duodenal folds is predictive of untreated adult celiac disease.

The loss of duodenal folds visible endoscopically has recently been reported as being a marker for celiac disease. We have investigated the sensitivity and specificity of this finding with a prospective study in 75 patients with symptoms or results of investigations compatible with celiac disease. Reported duodenal fold appearance was compared with histological findings, disaccharidase levels, and clinical diagnosis. Fifteen patients were found to have celiac disease and 11 had reduced or absent duodenal folds compared with only 2 of 60 patients who did not have celiac disease (p less than 0.0001). This finding has a sensitivity of 73%, specificity of 97%, and positive predictive value of 85%. Duodenal folds were not reported as being abnormal in seven patients with hypolactasia or two with giardiasis and did not appear to be influenced by age. A reduction in the number or height of duodenal folds as seen endoscopically in the second part of the duodenum is a specific and sensitive sign of celiac disease. Endoscopists should biopsy the duodenum for celiac disease whenever the duodenal folds appear to be reduced or absent.

Adult↗