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Biomedical subjects

D Wingate

Publications and source records attributed to D Wingate.

At least 19 recordsLinked to original sources

Guidelines for adults on self-medication for the treatment of acute diarrhoea.

Acute uncomplicated diarrhoea is commonly treated by self-medication. Guidelines for treatment exist, but are inconsistent, sometimes contradictory, and often owe more to dogma than evidence. An ad hoc multidisciplinary group has reviewed the literature to determine best practice. In general it is recognized that treatment of acute episodes relieves discomfort and social dysfunction. There is no evidence that it prolongs the illness. Self-medication in otherwise healthy adults is safe. Oral loperamide is the treatment of choice. Older anti-diarrhoeal drugs are also effective in the relief of symptoms but carry the risk of unwanted adverse effects. Oral rehydration solutions do not relieve diarrhoea, and confer no added benefit for adults who can maintain their fluid intake. Probiotic agents are, at present, limited in efficacy and availability. Antimicrobial drugs, available without prescription in some countries, are not generally appropriate for self-medication, except for travellers on the basis of medical advice prior to departure. Medical intervention is recommended for the management of acute diarrhoea in the frail, the elderly (> 75 years), persons with concurrent chronic disease, and children. Medical intervention is also required when there is no abatement of the symptoms after 48 h, or when there is evidence of deterioration such as dehydration, abdominal distension, or the onset of dysentery (pyrexia > 38.5 degrees C and/or bloody stools).

Acute Disease↗

[Motility disorders of the small intestine in functional intestinal disorders].

Functional digestive disorders have their origin in disturbances of the digestive motility control. This control ensured primarily by the "gut brain", which is able to integrate sensitive information from mucosal receptors and to organize an appropriate motor response from a choice of predetermined "programs". The gut brain is in close relationship with the central nervous system (CNS) which collects in fact most of the information and modulates the sensitive integration and the motor response of the enteric nervous system (ENS). Thus, a perturbation of the CNS, such as stress, may induce a dysfunctioning of the ENS, resulting in motor disturbances and finally functional digestive disorders. In a first study involving fasting healthy volunteers, we showed that stress produces a significant reduction of the intestinal migrating motor complexes (MMC). In a second study, patients with irritable bowel syndrome (IBS) were subjected to stress and compared to patients with inflammatory bowel disease and to healthy controls. All subjects exhibited a decrease of MMC; however, total depletion was observed in numerous IBS patients, together with a characteristic irregular motor activity which was associated with symptoms. Finally, 24-hour recordings of the intestinal motility in these patients showed an entirely normal pattern during sleep and when abnormalities just awakening in association with symptoms. Stress-induced perturbation of the CNS in IBS patients seems to provoke an inappropriate modulation of the motor activity programmed by the ENS, resulting in motor disturbances and finally in the symptoms of the disease.

Central Nervous System↗

Circadian variation in the propagation velocity of the migrating motor complex.

Using twin intraluminal pressure-sensitive radiotelemetric capsules for prolonged monitoring of proximal small bowel motility in healthy volunteers, we observed a significant (p less than 0.001) variation between daytime (6.44 +/- 0.74 cm/min, mean +/- SD) and nocturnal (2.90 +/- 0.35 cm/min) propagation velocities of the migrating motor complex. An identical variation in propagation velocity was observed in patients suffering from the irritable bowel syndrome. These data suggested a circadian variation, but did not exclude alternative hypotheses. Data were therefore compiled from healthy sheep and pigs supplied with ad libitum rations each morning and adapted to a 12 h light, 12 h dark schedule. Recording from implanted electrodes showed a significant (p less than 0.01) reduction in migrating motor complex velocity from 27.8 +/- 5.1 cm/min by day to 16.7 +/- 3.1 cm/min at night in sheep, and from 20.6 +/- 2.4 to 13.4 +/- 1.9 cm/min in pigs. The nocturnal reduction remained when the animals were fed in the evening. These observations suggest a circadian variation in mammalian migrating motor complex propagation velocity that is not merely a function of variation in intraluminal content.

Animals↗

Use of pentagastrin test as a combined teaching and research project for medical students.

The pentagastrin acid-secretion test was used to teach medical students gastric investigation, the structure of a controlled trial, and the application of non-parametric statistics to the analysis of imperfect data. This teaching project also yielded considerable original data from 150 subjects on the extra-gastric effects of pentagastrin and histamine-receptor antagonists. Some, but not all, of the somatic symptoms induced by pentagastrin were abolished by cimetidine; however, the combination of pentagastrin and cimetidine induced a significant (p < 0.02) incidence of dizziness.

Cimetidine↗

Effect of metoclopramide on interdigestive myoelectric activity in the conscious dog.

The effect of two-hour infusions of metoclopramide at five different doses on interdigestive intestinal electrical activity was studied in four conscious fasting dogs. Spike activity during the infusions was quantitatively compared with activity during preceding and following periods of saline infusion. The effect of the drug was the enhancement of spike activity during migrating myoelectric complexes (MMC) without disruption of the fasting pattern; the effect was most marked in the proximal small intestinal and diminished distally. As in other published studies with metoclopramide, its effects were variable and not dose dependent. The enhancement of the MMC by an exogenous stimulus, not previously reported, provides indirect evidence for cholinergic mediation of cyclical motor activity, and also suggests a rational basis for therapy.

Animals↗

Quantitative effect of oral feeding on gastrointestinal myoelectric activity in the conscious dog.

Gastrointestinal myoelectric activity was recorded in seven studies in five dogs during two hours of fasting immediately followed by feeding and subsequent recording for four hours. In four studies serial plasma samples were taken for radioimmunoassay of insulin and gastrin. In all animals there was a significant reduction (P less than 0.01) in gastric basic electrical rhythm (BER) frequency on feeding which was sustained throughout the postprandial period. There was no change in the duodenal BER. Feeding induced a significant (P less than 0.01) increase in overall jejunal and ileal (but not duodenal) spike activity. Ileal (but not jejunal) spike activity again increased significantly (P less than 0.05) after the first two post-prandial hours. The changes in serum gastrin or in serum insulin did not appear to account for most of the observed changes in myoelectric activity, suggesting that other humoral and/or neural factors mediate the response to food.

Animals↗

Automated high-speed analysis of gastrointestinal myoelectric activity.

The value of myoelectric recording in the gastrointestinal tract has been limited by the difficulty of analyzing the prolonged recordings which are required to demonstrate integrated physiological activity. This problem has been solved by the use of a tape recording system with accelerated replay, originally developed for cardiac monitoring. Rapid replay not only reduces the time required for data retrieval but also increases the frequency of the recorded signals to allow electronic separation of fast and slow wave activity for on-line conversion into digital pulses suitable for computer analysis. The technique is illustrated by the analysis of an imperfect prolonged multichannel recording of cannine gastrointestinal myoelectric activity, demonstrating some of the possibilities for data analysis and error detection inherent in the system.

Animals↗

The eupeptide system: A general theory of gastrointestinal hormones.

Increasing knowledge of gastrointestinal "hormones" suggests a system which differs in many, if not most, respects from other endocrine systems. The established model of endocrine function, derived from studies of the hormones regulating growth, metabolism, and sexual function, is inappropriate; attempts to apply concepts such as the importance of plasma-hormone concentrations to the digestive tract have met with limited success. A new model of the gastrointestinal polypeptide system is proposed in which local "paracrine" action may be no less important, or more important, than distant "endocrine" action, and in which modulation of integrated neural control is a major function. The application of the word "hormone" to this polypeptide system is a devaluation of the term and an obstacle to the design of relevant physiological studies; an alternative nomenclature is proposed.

Cholecystokinin↗

Luminal distension as a possible consequence of experimental intestinal perfusion.

In an experimental jejunal perfusion study, distress in healthy subjects occurred during eight out of 16 perfusions in which intestinal secretion was provoked. Calculation demonstrates the volumetric consequences of inadequate recovery of secretory perfusates, and analysis of the perfusion studies shows that distress was significantly associated with poor recovery of the perfusate. These observations are pertinent to increasing interest in the phenomenon of intestinal fluid secretion.

Carbon Radioisotopes↗