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Biomedical subjects

O B de Muckadell

Publications and source records attributed to O B de Muckadell.

10 recordsLinked to original sources

[Antibiotic treatment of travellers' diarrhea].

UNLABELLED: This review should be cited as: De Bruyn G, Hahn S, Borwick A. Antibiotic treatment for travellers' diarrhoea (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. A substantive amendment to this systematic review was last made on 21 May 2000. Cochrane reviews are regularly checked and updated if necessary. BACKGROUND: Traveller's diarrhoea is a syndrome frequently encountered in persons crossing an international boundary. Diarrhoea can lead to significant discomfort and interference with travel plans. Bacterial pathogens are a frequent course of this syndrome. Several antibiotics have been tested for efficacy in reducing the duration and severity of the illness. OBJECTIVES: The aims of the review were to access the effects of antibiotics on traveller's diarrhoea in relation to the duration of illness, severity of illness, and adverse effects of medications. SEARCH STRATEGY: The Cochrane Collaboration Trials Register, MEDLINE, and EMBASE were searched. Additional trials were identified by hand searching. Content experts were contacted. SELECTION CRITERIA: All trials in any language in which travellers older than five years were randomly allocated to treatment for acute non-bloody diarrhoea with antibiotics and where the causative organism is not known at allocation. DATA COLLECTION AND ANALYSIS: Two reviewers assessed trial quality and extracted data. MAIN RESULTS: Twenty published studies met inclusion and quality criteria for inclusion. Twelve studies were placebo-controlled. A meta-analysis for the primary outcome was not feasible. All of the ten trials reported a significant reduction in duration of diarrhoea in participants treated with antibiotics compared with placebo. Data from two trials demonstrated a small reduction for antibiotic treated patients in the number of unformed stools passed per each 24 hour period from randomisation up to 72 hours. Data from six trials demonstrated a greater number of participants being cured of diarrhoea by 72 hours (odds ratio [OR] 5.9, 95% confidence interval [CI] 4.06 to 8.57). Data regarding side effects were available from five trials. There was wide variation in the prevalence of side effects reported in different trials. Persons taking antibiotics experienced more side effects than those taking placebo (OR 2.37, 95% CI 1.5 to 3.75). REVIEWERS' CONCLUSION: Antibiotic treatment is associated with shorter duration of diarrhoea but higher incidence of side effects. Trials generally do not report duration of post-treatment diarrhoea using time-to-event analyses, and should do.

Anti-Bacterial Agents↗

Secretin, its discovery, and the introduction of the hormone concept.

The English physician E. H. Starling discovered in collaboration with the physiologist W. M. Bayliss secretin, the first hormone, in 1902. Three years later they introduced the hormone concept with recognition of chemical regulation, early regulatory physiology took a major step forward. The isolation and subsequent synthesis of secretin in the 1960s prepared the way for immunological techniques. Radioimmuno assays in the 1970s enabled demonstration of a direct endocrine role of secretin. Cloning and molecular hybridisation in the 1990s identified production site structure, precursor and evolutionary relation to other gastrointestinal peptides and to the secretin receptor. Although secretin was the first substance to be established as a hormone, even today our understanding is far from complete.

Amino Acid Sequence↗

Endoscopic sphincterotomy for common bile duct stones in younger patients.

BACKGROUND AND STUDY AIMS: Most follow-up studies of patients with common bile duct stones treated with endoscopic sphincterotomy include older patients. Therefore, the aim of the present study was to do a medium-term follow-up of patients under the age of 60 years, who underwent endoscopic sphincterotomy and removal of common bile duct stones. METHODS: Eighty-six (68 women) consecutive patients less than 60 years of age (median age 47 years) were evaluated. The median observation time after endoscopic sphincterotomy was 27.1 months. Complete follow-up was accomplished in 80 patients. RESULTS: Twenty-five patients had undergone cholecystectomy prior to the endoscopic sphincterotomy. Sixty-one patients were discharged after endoscopic sphincterotomy with gallbladder left in situ. Cholecystectomy was not needed in 27 patients, of whom 23 had gallbladder stones. In 13 of 61 patients subsequent elective cholecystectomy was planned at the time of endoscopic sphincterotomy. Recurrent attacks of biliary colic required elective cholecystectomy in another thirteen patients. Acute cholecystectomy was undertaken in eight patients due to acute cholecystitis (n = 4) or biliary colic (n = 4). Seven of eight acute cholecystectomies were performed within 152 days after the endoscopic sphincterotomy. The overall median time until cholecystectomy was 51 days (25-75 percentiles, 23-103 days). CONCLUSIONS: One third of the patients had been cholecystectomized prior to the endoscopic treatment of their common bile duct stones. Nearly half of the young patients discharged after endoscopic sphincterotomy for common bile duct stones with the gallbladder left in situ at the time of endoscopic sphincterotomy managed well without any need for cholecystectomy.

Adult↗

Gastroenteropancreatic hormonal changes during exercise.

Peripheral plasma concentrations of gastroenteropancreatic peptides were measured during a 3-h period of bicycle exercise at 40% of maximal oxygen uptake in six normal men. Marked increases (P < 0.02) were found in vasoactive intestinal polypeptide (VIP) [1.8 +/- 0.7 (rest) vs. 22.3 +/- 5.4 pmol x l-1 (mean +/- SE) (3 h)], secretin (0.5 +/- 0.5 vs. 11.1 +/- 2.7 pmol x l-1), pancreatic polypeptide (PP) (4.0 +/- 1.5 vs. 46.3 +/- 11.5 pmol x l-1), somatostatin (SRIF) (12.8 +/- 1.2 vs. 17.7 +/- 0.6 pmol x l-1), whereas no changes occurred in gastric inhibitory polypeptide (37.3 +/- 5.9 vs. 39.2 +/- 9.8 pmol x l-1). Immunoreactive insulin and C-peptide decreased from 0.08 +/- 0.004 and 0.39 +/- 0.03 pmol x l-1, respectively, to 0.04 +/- 0.003 (P < 0.005) and 0.13 +/- 0.02 (P < 0.001). The significant decrease in C-peptide and in the C-peptide-to-insulin molar ratio indicate decreased insulin secretion and clearance, respectively, during exercise. Plasma glucose decreased [5.0 +/- 0.1 (rest) vs. 4.2 +/- 0.3 mmol.l-1 (3 h)] (P < 0.01). During 3 h of rest, none of the measured parameters had changed. The marked exercise-induced changes in plasma concentrations of PP, secretin, VIP, and SRIF are provocative. We know in detail neither the stimuli for the release of these peptides nor their physiological role during exercise.

Adolescent↗

Serum cholinesterase variants in the Danish population.

A total of 1278 adult patients were screened for serum cholinesterase (E.C. 3.1.1.8) variants. The following were used for phenotyping of variants: dibucaine, fluoride, chloride, and urea. The observed incidence of cholinesterase variants in the Danish population was similar to that found in other European countries.

Cholinesterases↗

Nervous release of vasoactive intestinal polypeptide in the gastrointestinal tract of cats: possible physiological implications.

1. The release of vasoactive intestinal polypeptide (VIP) into blood from the gastrointestinal tract was studied when eliciting autonomic nervous effects known to be mediated via non-adrenergic, non-cholinergic nerve fibres. All studies were performed on animals given atropine. 2. Electrical stimulation of the low threshold vagal fibres to the stomach did not significantly change gastric volume or VIP concentration in the venous effluent from the stomach. Stimulating the high threshold fibres, on the other hand, produced a gastric relaxation concomitant with a significant increase of venous plasma VIP concentrations. When eliciting a similar vagal relaxation of the stomach by distending a balloon the oesophagus a significant increase of venous plasma VIP concentration was also recorded. 3. Mechanical stimulation of the mucosa of the small bowel increased intestinal blood flow and a significant increase of venous plasma VIP concentration was observed. 4. Stimulation of the pelvic nerves to the colon produced a transient vasodilation and a significant increase of VIP in the venous effluent from the large bowel. A maintained vasodilation in the colon was induced by mechanically stimulating the rectal mucosa. This vascular response was accompanied by a significant raise of venous plasma VIP concentration. 5. The results demonstrate that all the studied nervous effects known to be mediated via non-adrenergic, non-cholinergic nerve fibres were accompanied by significant increases of the VIP concentration in the venous effluent. The possible physiological implications of these findings are discussed and it is proposed that VIP may be a neurotransmitter in the gastrointestinal tract.

Adrenergic Fibers↗

Vagal, cholinergic regulation of pancreatic polypeptide secretion.

THE EFFECT OF EFFERENT, PARASYMPATHETIC STIMULATION UPON PANCREATIC POLYPEPTIDE (PP) SECRETION WAS STUDIED IN THREE WAYS: (a) Plasma PP concentrations increased in response to insulin-induced hypoglycemia in both normal subjects, from 11 pM (9.5-12.5) to 136 pM (118-147), n = 8 (median and interquartile range) and in duodenal ulcer patients, from 33 pM (21-52) to 213 pM (157-233), n = 7. The PP response to hypoglycemia was diminished by atropine in normal subjects (P < 0.005) and completely abolished by vagotomy in the duodenal ulcer patients. (b) Electrical stimulation, 8 Hz, of the vagal nerves in anesthetized pigs induced an increase in portal PP concentrations within 30 s from 32 pM (28-39) to 285 pM (248-294), n = 12. Minimal stimulatory frequency was 0.5 Hz and maximal stimulatory frequency 8-12 Hz. Atropine inhibited the PP response to electrical stimulation. Median inhibition with 0.5 mg of atropine/kg body wt was 74%, range 31-90%, n = 6. The response was eliminated by hexamethonium. Adrenergic alpha and beta blockade did not influence the release of PP in response to vagal stimulation. (c) Acetylcholine stimulated, in a dose-dependent manner, the secretion of PP from the isolated perfused porcine pancreas, half-maximal effective dose being 0.19 muM; maximal PP output in response to 5 min stimulation was 228 pmol, range 140-342 pmol, n = 5. Atropine completely abolished this response.The results of the present study together with the previously demonstrated poor PP response to food in vagotomized patients, indicate that vagal, cholinergic stimulation is a major regulator of PP secretion.

Acetylcholine↗

Plasma insulin concentration during physiological variations in immunoreactive plasma secretin.

The effect of endogenous and exogenous secretin on fasting plasma insulin and glucose concentrations in peripheral venous blood was studied. In 10 non-diabetic subjects intragastric instillation of 300 ml 0.1 mol/l hydrochloric acid increased the plasma secretin concentration significantly. This increment did not influence insulin or glucose concentration. Control experiments with intragastric instillation of 300 ml of isotonic saline did not influence the plasma concentration of secretin, insulin or glucose. In four other non-diabetic persons no significant changes were found in plasma insulin or glucose concentration during an i.v. infusion of pure natural porcine secretin in doses of 0.1, 0.3, 1.0 and 3.0 clinical units/kg/h. The results suggest that secretin is without effect on insulin secretion in the fasting normal subject.

Adult↗

Preparation of 125I-labeled synthetic porcine secretin for radioimmunoassay.

Synthetic porcine secretion was labelled by the conjugation-labelling method of Bolton & Hunter, the lactoperoxidase method, the gaseous diffusion method, and the chloramine-T method. The chloramine-T technique was adapted as routine method. Ten mug (3.27 nmol) peptide was reacted with 5 mCi of Na125I at a concentration of chloramine-T of 1.3 mmol/l. Synthetic secretin was suitable for labelling for at least eight months when stored as dry matter in nitrogen-filled glass ampoules. Purification and separation of labelled from unlabelled hormone was carried out by gel-permeation chromatography on Sephadex G-50 superfine. The labelled preparation had a specific radioactivity of 405 +/- 33 muCi/nmol (mean +/- SEM., n = 9) and was unable for six days. 6-tyrosyl-secretin took more iodine compared to porcine synthetic secretin but had lower immunoreactivity with all antisera tested.

Animals↗