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Biomedical subjects

N W Read

Publications and source records attributed to N W Read.

At least 73 records · Page 4Linked to original sources
PubMed1995

Constipation and incontinence in the elderly.

We summarize the prevalence and causes of constipation and incontinence in an elderly, drawing particular attention to the roles of immobility, dietary fiber, and dehydration. The physiology of fecal impaction is described in detail, and neurological and mechanical causes (rectal prolapse, rectocele, and hemorrhoids) of constipation are discussed. Consideration is also given to constipation associated with diverticular disease and ulcerative colitis. We also discuss the pathogenesis of fecal incontinence in the elderly, paying particular attention to fecal impaction and neurological causes that result in both constipation and incontinence. The importance of previous obstetric trauma and pudendal enuropathy is emphasized. We conclude with detailed guidelines of the clinical assessment and management of an elderly patient with a disorder of defecation.

Aged↗
PubMed1995

Abnormal sensitivity to duodenal lipid infusion in patients with functional dyspepsia.

BACKGROUND AND OBJECTIVES: Patients with functional dyspepsia exhibit increased sensitivity to gastric distension (mechanoreceptors) and to meals rich in fat (chemoreceptors). The aim of this study was to test whether these patients were abnormally sensitive to intraduodenal lipid, and whether this stimulus altered gastric mechanosensitivity. METHODS AND DESIGN: Experiments were conducted on 10 patients and 10 healthy controls. The stomach was distended with a flaccid bag during duodenal infusion of either 10% Intralipid or 0.9% saline. Intragastric pressure was recorded continuously, and the participants were asked to report gastric sensations of fullness and discomfort. RESULTS: Intragastric pressure profiles during distension were similar in patients and controls. Lipid decreased intragastric pressure and reduced phasic contractility. Patients showed enhanced sensitivity to gastric distension compared with controls during both saline and lipid infusions. In the controls, threshold volumes for fullness and discomfort were higher during lipid than saline infusion. In the patients, the sensation of fullness occurred at lower volumes during lipid infusion, whereas discomfort occurred at similar volumes but lower intragastric pressures. Most patients experienced nausea and bloating and three patients vomited during lipid infusion, but remained asymptomatic during saline infusion. Controls reported no symptoms during either infusion. CONCLUSION: Dyspeptic patients have increased sensitivity to both gastric distension and intraduodenal lipid. In contrast to controls, lipid sensitizes their stomachs to distension.

Abdominal Pain↗
PubMed1995

The effect of oral vancomycin on chronic idiopathic constipation.

BACKGROUND: A case study reporting the efficacy of oral vancomycin in a patient with chronic idiopathic constipation prompted this prospective trial of oral vancomycin in eight female patients (aged 21-61 years) with severe constipation resistant to the action of dietary fibre. METHODS: The trial was divided into two consecutive 14-day periods. During the first period, each patient was given ispaghula, 3.5 g twice a day, and during the subsequent period they took 250 mg vancomycin t.d.s. per os, as well as the fibre supplement. During both periods they collected stools and recorded daily bowel symptoms (stool frequency, straining, stool consistency, subjective stool volume) in a diary. At the end of each period whole gut transit time and the breath hydrogen response to a standard meal, giving oro-caecal transit time, were measured along with gastrointestinal symptoms which were assessed on visual analogue scales. RESULTS: Vancomycin caused a significant improvement in stool frequency, consistency, ease of defecation and the amount of stool patients felt they produced (all P < 0.05), but objective measures of daily stool weight and whole gut or oro-caecal transit time were not significantly different. Basal breath hydrogen levels were higher after vancomycin treatment in seven out of eight patients. One patient experienced a complete remission of symptoms when she took vancomycin and remains in remission after 14 months. This patient showed no elevation in basal breath hydrogen level. CONCLUSION: Although this study does not support the use of vancomycin for most patients with constipation, the results suggest that modification of the intraluminal flora may be of value in the treatment of the occasional case of idiopathic constipation.

Administration, Oral↗
PubMed1995

Hereditary proctalgia fugax and constipation: report of a second family.

A second family with hereditary proctalgia fugax and internal anal sphincter hypertrophy associated with constipation is described. Anorectal ultrasonography, manometry, and sensory tests were conducted in two symptomatic and one asymptomatic subjects within the same family and further clinical information was obtained from other family members. The inheritance would correspond to an autosomal dominant condition with incomplete penetration, presenting after the second decade of life. Physiological studies showed deep, ultraslow waves and an absence of internal anal sphincter relaxation on rectal distension in the two most severely affected family members, suggesting the possibility of a neuropathic origin. Both of these patients had an abnormally high blood pressure. After treatment with a sustained release formulation of the calcium antagonist, nifedipine, their blood pressure returned to normal, anal tone was reduced, and the frequency and intensity of anal pain was suppressed. These together improved the quality of the patients' sleep, which had previously been very troubled because of night time attacks of anal pain.

Adult↗
PubMed1995

Gastric emptying and the symptoms of vection-induced nausea.

OBJECTIVES: To examine the hypothesis that nausea during vection arises directly from an underlying alteration in gastric motility. DESIGN: The simultaneous application of vection and assessment of gastric emptying of a liquid, non-nutrient test meal allowed the examination of the interaction between changes in gastric motility and symptoms. METHODS: Studies were conducted in 14 volunteers. Vection was induced by seating the subject inside a rotating circular drum, which was painted with vertical black and white stripes. In the control study (n = 8) the drum was not rotated. Gastric emptying was measured by gamma scintigraphy of a radiolabelled isosmotic saline test meal. RESULTS: Vection induced upper abdominal sensations (epigastric awareness) in 10 subjects, eight of whom subsequently reported nausea; autonomic symptoms of sweating and pallor were experienced by 12 subjects. Two subjects remained completely asymptomatic during vection. None of the subjects experienced any sensations during the control study. Gastric emptying was significantly delayed during vection (P < 0.01). There was a highly significant correlation between gastric emptying and the intensity of nausea. However, examination of the gastric emptying profiles did not support any direct association between altered gastrointestinal motor activity and symptoms. Two subjects with slowing of gastric emptying exhibited no nausea or upper abdominal symptoms, while another two experienced nausea when the underlying rate of gastric emptying was similar to that of the control period. CONCLUSIONS: The delay in gastric emptying of a liquid test meal induced by vection appears to be a variable epiphenomenon of nausea. A cause and effect relationship between gastric emptying and nausea therefore appears unlikely.

Adult↗
PubMed1994

Anorectal function after restorative proctocolectomy and low anterior resection with coloanal anastomosis.

Anorectal manometry and electromyography were studied in 17 patients before and after restorative proctocolectomy with stapled pouch-anal anastomosis, in ten patients before and after low anterior resection with stapled coloanal anastomosis, and in 35 normal controls. More than 80 per cent of patients in both groups developed abnormal oscillation of anal pressure after operation (amplitude 15-60 (median 25) cmH2O, frequency 4-10 (median 8) per min) and showed no anal relaxation in response to intermittent neorectal distension. All patients lost discriminative rectal sensation and none could perceive a normal desire to defaecate. Patients with postoperative soiling had a greater amplitude of anal pressure oscillation and lower minimum basal pressure, although those who underwent coloanal anastomosis had a greater risk of incontinence because of large asynchronous oscillations in neorectal pressure. The common pathophysiological features after restorative proctocolectomy and coloanal anastomosis probably relate to damage to the autonomic and enteric nerve supplies. The presence of an unstable internal anal sphincter may be an important cause of postoperative nocturnal incontinence.

Adult↗
PubMed1994

Evaluation of the motor and sensory components of the pudendal nerve.

Extensive neurophysiological investigations consisting of different techniques to evaluate the efferents and afferents of the pudendal nerve were carried out in 27 healthy subjects. These investigations included motor evoked potential recordings from the external anal sphincter in response to magnetic stimulation of the cortex and lumbosacral roots, measurement of sacral reflex latency to magnetic and electrical stimulation, and cortical sensory evoked potential recording after stimulation of the dorso-genital nerve and anal canal. Motor latencies after transcranial magnetic stimulation to the anal sphincter were 25.1 +/- 2.9 msec at rest and 20.9 +/- 2.0 msec with voluntary sphincter contraction (facilitation). Motor latency after lumbosacral root stimulation was 3.7 +/- 1.0 msec. Mean sacral reflex latency after magnetic stimulation was 43.8 +/- 11.2 msec and was significantly longer than after electrical stimulation (37.0 +/- 7.2 msec; P < 0.05). P1 latency of the sensory evoked potentials after dorso-genital nerve stimulation was 40 +/- 3 msec and was significantly shorter than after anal stimulation 46 +/- 3 msec (P < 0.01). Evoked potential recording allows us to study both upper and lower motor neuron components to the anal sphincter. The present study paves the way for the combined application of these tests in the evaluation of disorders of the pelvic floor.

Adult↗
PubMed1994

Effect of guar gum on hunger and satiety after meals of differing fat content: relationship with gastric emptying.

To determine whether the satiating effects of fiber are due to delaying gastric emptying or slowing absorption of meals, 3% guar gum was added to high- and low-fat soups and gastric emptying rate, hunger, and satiety were measured in eight male volunteers. Guar gum delayed the emptying of the low-fat soup but the small delays in the return of hunger and decline of fullness were significantly correlated with the gastric emptying, suggesting mediation by gastric mechanoreceptors. The high-fat soup also emptied more slowly but this had no effect on the return of hunger or the decline in fullness. The delays in the return of hunger and decline of fullness were far greater when guar gum was added to the fatty soup; these delays were not correlated with the small additional delay in gastric emptying. This is more compatible with slowed absorption and prolonged contact of nutrients with intestinal chemoreceptors.

Adult↗
PubMed1994

Gastrointestinal adaptation to enhanced small intestinal lipid exposure.

Studies were performed on 20 male adult rats to investigate the effects of chronic intermittent infusion of lipid and physiological emulsifier into the distal small intestine on stomach to caecum transit time (SCTT) of the head of a test meal. SCTT was measured using environmental hydrogen analysis. Ileal lipid infusion normally delays gastric emptying and small intestinal transit (p < 0.001), but chronic intermittent infusion of lipid, given three times a week gradually reduced the delay in transit time until by four weeks it was no longer than control values. The lipid induced delay did not return during the four weeks after the chronic infusion had finished. Intermittent infusion of physiological emulsifier into the distal small intestine for four weeks did not change the control SCTT or the acute response to an ileal lipid infusion. SCTT of the head of the meal did not change in the four weeks after the physiological emulsifier infusion had stopped. In conclusion these results show that infusing rats intermittently with lipid for four weeks results in desensitisation of the mechanisms by which distal small intestinal lipid regulate SCTT of the head of a meal. This adaptation is not reversed within four weeks of withdrawal of the lipid infusion. These results emphasise the importance of assessing recent dietary history when assessing gastric emptying and small bowel transit times.

Animals↗
PubMed1994

The effects of loxiglumide on food intake in normal weight volunteers.

The aim of this paper was to investigate the effects of the CCK, a receptor antagonist loxiglumide on food intake, hunger and fullness in humans. A double blind, placebo controlled, cross-over test was carried out, with subjects taking one loxiglumide or one placebo tablet three times a day, 15 min before main meals or at comparable intervals. The work was carried out at the Centre for Human Nutrition, Northern General Hospital, University of Sheffield, on 11 healthy, normal weight, male and female volunteers. The following were measured: weighted-intake measurement of food intake during drug and placebo treatment; laboratory test of food intake on day three of each treatment; hunger and fullness ratings throughout this meal. A small, non-significant, increase in food intake as measured by the weighed intake diaries (8577 +/- 636 vs 7895 +/- 569 kJ (2049 +/- 152 vs 1886 +/- 136 kcal); P = 0.17) was seen during loxiglumide treatment, but no effect on food consumption from the evening test meal was observed and no effect on feelings of hunger and fullness before or after this meal was seen. These results do not support the hypothesis that, in the free feeding situation, endogenously released CCK is involved in the reduction of food intake or inhibition of hunger. However, a different dose of route of administration or a larger group of subjects may reveal an effect of loxiglumide on feeding in humans.

Adolescent↗
PubMed1994

Feedback regulation and sensation.

The gut is a long tube; food goes down it and across it. Its purpose is to process the food that is consumed in order to optimize absorption of nutrients. It works rather like the reverse of an assembly line in a manufacturing plant with different regions of the gastrointestinal tube specialized sequentially for storage, acid digestion, alkaline digestion, absorption, fermentation, and disposal of waste products. Like an assembly line, it will only work efficiently if the delivery of material to the next process in coordinated closely with the optimum rate of that process. In the gut, the delivery of material is achieved by the propulsive activity of the gastrointestinal smooth muscle, which is in turn programmed by the enteric nervous system and orchestrated by neurohumoral responses to the content of the digesta. It is a finely tuned system; any disturbance can impair absorption and give rise to abdominal discomfort. The stomach is a key organ in the "gastrointestinal dissembly line," It not only commences the digestive process under highly acidic conditions, it stores the masticated food as in a hopper, delivering the acidic digesta or chyme into the duodenum at a rate that is commensurate with the rate at which it can be digested and the products of digestion can be absorbed. The rate at which material enters the small intestine is crucial to achieving optimum nutrition; too fast, and it overwhelms the functional capacity of the small intestine, causing malabsorption and diarrhoea; too slow, and it inhibits the consumption of another meal. The gastrointestinal tract can normally process three medium-sized meals a day.

Animals↗
PubMed1993

The effect of preliminary bowel preparation on a simple test of colonic transit in constipated subjects.

The abdominal distribution of orally ingested radioopaque markers is used to assess total and segmental colonic transit in constipated patients, but interpretation may depend on whether studies are carried out on a full colon or one cleared of faeces. We asked 25 severely constipated patients (age 18-74; 22 F, 3 M) to ingest 50 polyethylene markers (4 mm x 2 mm) at breakfast on 2 occasions 1 month apart. No bowel preparation was used for study 1 but for the second study 2 doses of Sodium Picosulphate (2 x 10 mg) were taken 3 days before ingestion of the markers. All subjects reported a good result which had ceased a day before taking the markers. Marker distribution was assessed by a plain abdominal film taken 72 hours after ingestion. All 25 subjects had more than 50% of markers present at 72 h in study one. Of these 4 showed evidence of outlet obstruction with more than 50% of ingested markers in the rectum. In the remaining 21 subjects markers were distributed throughout the colon in a pattern indicating colonic inertia. Following the administration of purgative there was no significant change in the mean number of markers retained but patterns of marker distribution for individual subjects did alter. Of the 21 patients who previously had colonic inertia, 3 showed outlet obstruction and 1 showed no evidence of delayed transit. Of the 4 patients with a pattern of outlet obstruction in the first study, 2 showed no evidence of delayed transit after Picolax.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

The effect of posture on gastric emptying and intragastric distribution of oil and aqueous meal components and appetite.

BACKGROUND: It is uncertain whether gastric emptying of fat is determined mainly by its physical characteristics or chemical composition. In particular, the intragastric distribution of extracellular fat and the importance of that distribution to gastric emptying of fat is controversial. The effects of posture on gastric emptying, intragastric distribution, and appetite after ingestion of a meal containing oil and aqueous phases was evaluated. METHODS: Eleven volunteers consumed 60 mL 99mTc-(V)-thiocyanate-labeled olive oil and 290 mL 113mIn-labeled soup while sitting and while lying in the left lateral decubitus position. Hunger before and after the meal was recorded. RESULTS: In the sitting position, oil emptied from the stomach more slowly (P < 0.01) whereas in the decubitus position oil emptied faster (P < 0.01) than the aqueous phase. Oil was preferentially retained in the proximal stomach when sitting (P < 0.01), and more oil was retained in the distal stomach in the decubitus position (P < 0.05). The amount of oil that emptied in the first 180 minutes was not different between the two postures. The aqueous phase emptied much more slowly (P < 0.01) in the decubitus position. At 120 minutes and 180 minutes, subjects were less hungry (P < 0.05) in the decubitus position. In the decubitus position, hunger at 120 minutes and 180 minutes was related to the retention of oil (r > or = 0.79; P < 0.01) in the stomach. CONCLUSIONS: These results indicate that (1) gravity has a major effect on the intragastric distribution and relatively little effect on total stomach emptying of oil, and (2) postprandial hunger is affected by posture and, in the decubitus position, is inversely related to the amount of oil that has entered the small intestine.

Adolescent↗
PubMed1993

Is cholecystokinin a satiety hormone? Correlations of plasma cholecystokinin with hunger, satiety and gastric emptying in normal volunteers.

This study was designed to test the putative role of plasma cholecystokinin (CCK) in eating behaviour by examining the relationships between bioassayed plasma CCK concentrations and rated sensations of satiety and hunger following the ingestion of an appetizing nutrient-dense meal and between plasma profiles of CCK and scintigraphically determined gastric emptying in nine healthy male volunteers. Mean plasma CCK levels from the whole group showed a significant negative correlation with mean hunger ratings (r = -0.64) and a positive correlation with fullness (r = +0.68). However, there was considerable interindividual variation and negative correlations with hunger were only seen in three out of nine subjects and positive correlations with fullness in four out of nine subjects. In contrast, there was a strong relationship between the plasma CCK produced over the first 2 h after the meal and the half time for gastric emptying of the meal (r = -0.81). These data do not support a direct role for circulating levels of CCK in the control of hunger and satiety following a meal. Instead, the strong correlation with gastric emptying is compatible with release of CCK in response to nutrient delivery into the small intestine.

Cholecystokinin↗