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Biomedical subjects

N W Read

Publications and source records attributed to N W Read.

284 records · Page 16Linked to original sources
PubMed1976

Electrogenic glucose absorption in untreated and treated coeliac disease.

Using a method for measuring changes in transmural potential difference across the human jejunum in vivo, the operational kinetic parameters of 'Apparent Km' and PD max for the active electrogenic component of glucose absorption were estimated in a group of healthy volunteers and in patients with coeliac disease. Both the 'Apparent Km' (17+/2mM; mean +/SEM) and the PD max (8.6+/0.7 mV) in nine patients with untreated coeliac disease were significantly lower (p less than 0.005) than in the control group ('Apparent Km' = 74+/5mM; PD max 12.8+/0.9mV, n=20). Treatment of five coeliac patients by gluten withdrawal for less than three months increased significantly the values of both the "Apparent Km (35+/6mM) and the TPD max (11.4+/1.2mV). Treatment of five patients for more than six months caused a further increase in the values of both kinetic parameters ('Apparent Km' = 108+/13mM; PD max =15.6+/2.7mV) to levels which exceeded those in healthy subjects. The possible interpretations of the differences in the kinetic characteristics of electrogenic glucose transport between coeliac patients and healthy subjects are discussed.

Celiac Disease↗
PubMed1973

Effect of cigarette smoking on competence of the pylorus: preliminary study.

The competence of the pylorus was studied in 13 normal volunteers and nine dyspeptic patients by means of a radiological technique involving intubation of the duodenum. The pylorus was found to be competent in most normal individuals and in fewer than half of the dyspeptic patients. However, on smoking a cigarette, appreciable increase in duodenogastric reflux was seen in nine out of the 13 normal volunteers and in seven out of the nine dyspeptic patients. Such induced pyloric incompetence and the resultant regurgitation of duodenal juices may explain the increased incidence of gastritis and gastric ulceration in heavy smokers.

Adult↗
PubMedDate not supplied

The importance of 5-hydroxytryptamine receptors in the gut.

Most of the 5-hydroxytryptamine (5-HT) present in the adult human body is located in the gastrointestinal tract. The vast majority is contained in enteroendocrine cells, the rest exists mainly in myenteric interneurons separated from the mucosa by an intraenteric barrier. Physiological studies suggest that 5-HT plays a vital role in mediating both sensory and reflex responses to gastrointestinal stimuli and, thus, this transmitter is closely implicated in gut reactions. This review outlines some of the evidence for different 5-HT receptors, summarizes the role of 5-HT in mediating gut sensitivity and motor activity, secretion and more complex activities, such as emesis and diarrhoea and identifies the clinical role of drugs acting on 5-HT receptors in the treatment of emesis, diarrhoea, the control of abdominal pain and discomfort and the rectification of gastrointestinal motility.

Abdominal Pain↗
PubMedDate not supplied

Cerebral evoked potentials after rectal stimulation.

We obtained reproducible cortical evoked potentials (EPs) in response to electrical stimulation of the rectum with 1 Hz frequency. We found 2 distinctly different EPs in response to rectal stimulation. In 5 females, the EP had an early onset latency (mean 26 msec) with multiple positive and negative peaks. In 10 females, the EP had a later onset latency (mean 52 msec) and a trifid configuration, having a very prominent negative peak. The early onset EPs after rectal stimulation appeared very similar to the wave form of the cortical EPs recorded after pudendal nerve stimulation. Finding similar interpeak latencies in the early onset EP after rectal stimulation and the EP after pudendal nerve stimulation suggests that either the same pathway was used or that rectal stimulation also stimulated the pudendal nerve. It appears that we stimulated visceral afferents when we recorded late onset EPs, because the large EP amplitude declined rapidly with faster stimulation rates and also with greater number of averaging, and the sensation threshold was very unstable, all different to somatosensory EPs.

Adult↗
PubMedDate not supplied

An examination of the effects of isoenergetic intragastric infusions of pure macronutrients on cold pain perception in healthy human volunteers.

Our previous study demonstrated that meals, particularly when rich in fat, significantly reduced the pain induced by the cold pressor stimulus in healthy human subjects. To determine the mechanisms involved, the aim of this study was to bypass the taste and cognitive component of food and to investigate the scope of these analgesic effects with direct intragastric infusion of pure macronutrients in a group of 16 healthy human volunteers (eight male and eight female) on the response to cold-induced pain. All subjects underwent the cold pressor test (CPT) on three occasions in a counterbalanced order: before and after intragastric intubation and infusion of isoenergetic fat (10% intralipid), carbohydrate (CHO-maltodextrin), and a control infusion of isotonic saline. All solutions were of equal volume and administered at room temperature. The CPT was carried out four times on each test day, once before intubation, and 0.5, 1.5, and 2.5 h after intragastric infusion. Radial pulse and blood pressure measurements and visual analogue scales of mood/emotional state were carried out before and after each CPT. There were no significant differences in pain scores between the three test conditions, suggesting that by bypassing the cognitive and taste component of eating, the trigger for any postingestive analgesic effects of food are lost.

Adolescent↗
PubMedDate not supplied

Motor mechanisms associated with slowing of the gastric emptying of a solid meal by an intraduodenal lipid infusion.

The aim of this study was to define better the motor phenomena associated with the slowing of gastric emptying by a duodenal lipid infusion. Antral, pyloric and duodenal motility were recorded in 10 healthy subjects with a manometric assembly which incorporated multiple perfused side-holes and a sleeve sensor positioned astride the pylorus. The gastric emptying of a standard solid meal and the distribution of the ingesta between the proximal and distal stomach were monitored with a radionuclide technique. A triglyceride emulsion was infused into the duodenum for 45 min once 25% of the meal had emptied. The infusion caused significant slowing in the rate of gastric emptying (P less than 0.01). This slowing in gastric emptying was associated with the suppression of pressure waves in the distal antrum (P less than 0.01) and proximal duodenum (P less than 0.01), the induction of pressure waves isolated to a narrow pyloric segment (P less than 0.01), and a redistribution of ingesta from the distal to proximal stomach. These findings suggest that pressure waves isolated to the pylorus, changes in the intragastric distribution of ingested food, and changes in proximal duodenal motility may all act in concert with changes in antral motility to regulate the gastric emptying of solids.

Adult↗