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Biomedical subjects

W E Green

Publications and source records attributed to W E Green.

At least 19 recordsLinked to original sources
PubMed1979

Tracheal collapse after thyroidectomy.

Tracheal collapse after thyroidectomy is uncommon; when it occurs, complete airway obstruction is often sudden, unexpected and fatal. In this paper a patient treated for tracheal collapse by tracheostomy and followed up for 1 year is described and, from a review of the literature, a further 9 cases are presented. The aetiology of the condition, the patient at risk and the technique of management are discussed.

Adult↗
PubMed1978

Gastric emptying of ingested acid and its effects on plasma gastrin and secretin in duodenal ulcer subjects.

Abnormal acid production or handling is thought to be involved in duodenal ulceration. Gastric emptying of 25 mmol hydrochloric acid (250 ml 0.1 M solution) was studied by using an isotopic method in control and ulcer subjects. Plasma gastrin and secretin levels were simultaneously measured. Gastric emptying was significantly faster in ulcer subjects using several parameters. Plasma gastrin levels were suppressed in both groups, with equivocal differences between them. Mean plasma secretin levels showed no significant elevation in controls and at only one point in ulcer subjects. Mean elevation in plasma secretin levels during intermediate phase of gastric emptying (T30-70) correlated with rate of acid loss from stomach in both groups. Regression lines were significantly different in position, however, and indicated a higher threshold for secretin release in ulcer subjects. The significance of this in the pathogenesis of duodenal ulcer is discussed.

Adult↗
PubMed1977

The gastrointestinal myoelectric response to 13-Nle-motilin infusion during interdigestive and digestive states in the conscious dog.

Gastrointestinal myoelectric activity was studied in three conscious fasted dogs with electrodes surgically implanted in the stomach and small intestine, during separate and combined intravenous infusions of 13-norleucine motilin (13-nle-motilin) and pentagastrin (PG). Basal recordings confirmed the presence of regular interdigestive myoelectric complexes (MC's). 13-nle-motilin infusion below 50 ng/kg-h was without effect: higher doses up to 400 ng/kg-h resulted in the interpolation of one or more MC's in the spontaneous sequence. The rate of aboral transit of 13-nle-molitin-induced MC's did not differ significantly from that of spontaneous MC's. When MC's were abolished by feeding or PG infusion, simultaneous 13-nle-motilin administration was without effect on spike activity, but slightly attenuated the accelerating effect of gastrin on the gastric pacemaker frequency. The myoelectric events triggered by 13-nle-motilin suggest that in the conscious dog the polypeptide may not act directly on the smooth muscle cell, as it does in vitro, but through an extra-enteric neural control mechanism which is uncoupled by gastrin.

Aminocaproates↗
PubMed1976

Metabolism of histamine in secreting and isolated canine stomach.

Total 14C activity in juice secreted by gastric pouches of six dogs and seven isolated canine stomachs was determined in response to intravenous and intra-arterial infusions of histamine and [14C]histamine. The proportions of 14C attributable to histamine, Nalpha-methylhistamine (NalphaMeH), Nalpha,Nalpha-dimethylhistamine (NalphaNalphaMe2H), N-telle-methylhistamine (NtauMeH), imidazole acetic acid (ImAA), N-methylimidazole acetic acid (NtauMeImAA), acetylhistamine (AcH), and histaminol (HOH) were defined using thin-layer chromatography. Similar estimates were made at the end of infusions on blood, gastric mucosa, and gastric muscle. Methylation was the major, or sole, route of metabolism of histamine in the gastric mucosa, and the major product was inactive NtauMeH. Small quantities of the active NalphaMe derivatives, particularly NalphaNalphaMe2H, were identified in both the juice and mucosa. Little or no ImAA, NtauMeImAA, AcH, and HOH were present in juice from isolated stomachs while they did occur in the juice from intact dogs, demonstrating they are extragastric metabolites of histamine. A major mucosal function of methylation of histamine is inactivation, although NalphaMe derivatives formed may play a role in the secretagogue action of histamine.

Acetates↗
PubMed1976

Motilin-induced electrical activity in the canine gastrointestinal tract.

Myoelectric activity induced by a synthetic analogue of the duodenal polypeptide motilin, was studied in isolated vascular-perfused canine duodenum and stomach, and in conscious dogs with serosal electrodes implanted in the stomach and the small intestine. In the isolated preparation, the duodenum was found to be four times as sensitive as the antrum to the polypeptide, showing a dose-dependent increase in spike activity within two minutes after administration of the polypeptide. By contrast, in the conscious fasted animal, the only response to motilin, above a threshold dose, was the interpolation of a premature migrating myoelectric complex in the spontaneous interdigestive sequence, appearing fifteen to twenty minutes after the start of infusion. Since the essential difference between the ex vivo and the intact intestine was the preservation of efferent and afferent nervous connections in the latter, it seems that in the conscious animal, the response to exogenous motilin is modulated by the innervation of the intestine, or, alternatively, motilin interacts with the centre controlling the pattern of motor activity in the small intestine rather than directly with smooth muscle. The latter hypothesis is supported by the observation that motilin had no effect on the motor activity of the small intestine during the infusion of pentagastrin which abolishes spontaneous migrating myoelectric complexes.

Action Potentials↗
PubMed1976

Effects of 13-nle-motilin on the electrical and mechanical activity of the isolated perfused canine stomach and duodenum.

Synthetic 13-norleucine-motilin (13-nle-motilin), structural and biological analogue of the naturally-occurring duodenal polypeptide, motilin, is known to stimulate antral and duodenal motor activity in vitro, but delays gastric emptying in man. In this study the direct actions of the synthetic polypeptide on myoelectrical activity and intraluminal pressure have been studied in the isolated vascular-perfused canine stomach and duodenum. 13-nle-motilin increased intraluminal pressure in the pylorus and duodenum, and dose-response analysis showed the duodenum to be twice as sensitive as the pylorus to the polypeptide. Pressure changes in the antrum were small and not dose-related, but, whereas the basic electrical rhythm in the duodenum was not altered, slow wave frequency, rhythm, and propagation in the antrum were disturbed. Electronic analysis of the duodenal spike increase which accompanied pressure rises demonstrated correlations between increases in spikes, intraluminal pressure, and dose. These results show that the direct effect of the polypeptide on adjacent organs may explain the combination of increased motor activity with delayed gastric emptying as a consequence of disturbance in the co-ordination between antrum, pylorus, and duodenum.

Animals↗
PubMed1975

13-norleucine motilin versus pentagastrin: contrasting and competitive effects on gastrointestinal myoelectrical activity in the conscious dog.

In conscious fasted dogs, with chronically-implanted electrodes in stomach and small intestine, typical aborally-propagated interdigestive myoelectric complexes were induced by the infusion of 13-nor-leucine motilin (13-Nle-M); whereas when the normal interdigestive activity was abolished by the infusion of pentagastrin, the resulting 'postprandial' pattern of activity was not significantly modified by the administration of 13-Nle-M. Results from this study provide further evidence that Motilin as well as Gastrin may be involved in the control of gastrointestinal motility in dogs.

Animals↗
PubMed1970

The effect of dialysates and ultrafiltrates of plasma of saline-loaded dogs on toad bladder sodium transport.

In order to obtain direct evidence for the existence of a natriuretic hormone, dialysates and ultrafiltrates of plasma of dogs expanded with saline were tested for effects on sodium transport by the toad urinary bladder. Dialysate was obtained by dialysis of blood in vivo in a clinical dialyzer and by dialysis in vitro of small volumes of blood using a miniature model of the clinical dialyzer. Ultrafiltrates were prepared using selective molecular filters which permit passage of substances on the basis of molecular weight and three dimensional configuration. Dialysates and ultrafiltrates of hydropenic dogs caused a change in toad bladder potential difference of + 1% and in short circuit current of - 5%. In contrast, dialysates and ultrafiltrates from expanded dogs caused a change in potential difference of - 23% and in short circuit current of - 32%, a highly significant difference. Onset of reduction of short circuit current occurred within 3-5 min, reaching a maximum in 10-20 min. The effect was rapidly reversible, was specific for the serosal surface of the bladder, and could not be explained on the basis of nonspecific alterations in ionic composition or by dilutional effects. Ultrafiltrates of jugular vein plasma caused significantly more reduction of short circuit current than ultrafiltrates of femoral vein plasma. The data indicate the presence in plasma of saline-loaded dogs of a dialyzable inhibitor of toad bladder sodium transport. Ultrafiltrate studies using membranes of appropriate selectivity suggest the factor has a molecular weight of less than 3000.

Animals↗