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Biomedical subjects

B J Collins

Publications and source records attributed to B J Collins.

At least 91 records · Page 5Linked to original sources
PubMed1987

Application of microencapsulation for toxicology studies. II. Toxicity of microencapsulated trichloroethylene in Fischer 344 rats.

Gelatin-sorbitol microcapsules containing 44.1% trichloroethylene (TCE) were prepared and mixed in NIH-07 rodent meal diet and provided at microcapsule concentrations of 0 (untreated control group), 1.25, 2.5, 5.0, or 10% (equivalent to 0, 0.55, 1.10, 2.21, or 4.41% TCE, respectively) to groups of 10 male F344 rats for 14 days. An additional control group received diets containing 5% empty capsules. For comparisons, TCE dissolved in corn oil was administered by gavage to different groups of 10 male rats for 14 consecutive days at dose levels adjusted to correspond to those in the feed study. Treatment-related deaths occurred only in the highest dose group of the gavage study. Body weight gain and feed consumption were reduced in high-dose groups of both the feed and gavage studies. There was no measurable loss of TCE in feed sampled from the cages during the study. Dose-related increases in organ (liver and kidney) weight/body weight ratios, individual cell necrosis in the liver, and hepatic microsomal NADPH cytochrome c reductase and peroxisomal palmitoyl-CoA oxidase and catalase activities were found in both the dosed-fed and gavage groups. Induction of cytochrome P-450 occurred only in the dosed-feed study. There were no significant compound-related pathologic lesions observed in the kidneys, the only other organ examined microscopically. Differences in lethality, cytochrome P-450 levels, and induction of microsomal or peroxisomal enzyme activities were attributed to differences in the method of dosing (gavage versus dosed-feed). The demonstration of no significant loss of TCE from the feed and of similar toxic effects produced by microencapsulated TCE via feed and TCE in corn oil via gavage indicate that microencapsulation can provide an excellent alternative exposure route for studying the oral toxicological properties of volatile chemicals, such as TCE, in rats.

Animal Feed↗
PubMed1987

Cisapride: influence on oesophageal and gastric emptying and gastro-oesophageal reflux in patients with reflux oesophagitis.

A preliminary, double-blind placebo controlled trial of cisapride in reflux oesophagitis was conducted. Eighteen patients were allocated to treatment with either placebo or cisapride, 10 mg three times daily, orally, before meals. Gastric emptying of a scrambled egg meal, oesophageal transit of a liquid bolus and ambulatory monitoring of oesophageal pH were assessed before and after four weeks' therapy. Overall, gastric emptying rates were not influenced by cisapride, although a small but significant reduction in gastric isotope retention, 20 minutes after meal ingestion was observed in patients on the active drug. Oesophageal transit times were not altered by cisapride. A small but significant reduction in the duration of gastro-oesophageal reflux followed cisapride therapy when compared with placebo.

Adult↗
PubMed1986

Ethanol induced conformational changes of the peptide ligands for the opioid receptors and their relevance to receptor interaction.

The FT-IR (Fourier Transform Infrared) Spectrum of [Met 5]-enkephalinamide in aqueous solution shows the presence of both the beta-turn and beta-sheet conformations. The beta-turn and beta-sheet conformations of enkephalins have been proposed to play a role in receptor selectivity. Addition of ethanol alters these secondary structural features and hence the effect of ethanol on ligand-receptor interaction may be mediated primarily through conformational changes of the ligand rather than those of the receptor.

Animals↗
PubMed1986

A mathematical model for assessing risk of postoperative wound infection.

A mathematical model for predicting the risk of acquisition of postoperative wound infection in individuals or groups of patients is described. It is based on data from prevalence surveys of 41 hospitals and includes 1980 wounds. The factors included in the model, i.e., age, sex, length of pre-operative stay, type of operation, wound drainage, number of occupied beds in ward, and special factors, e.g., diabetes, steroid therapy, were obtained by stepwise regression analysis of the original data. Most of the ward facilities and practices were excluded as non-significant. The model has been modified for use with incidence studies and its accuracy confirmed in a further 1331 patients by comparing predicted and recorded infection rates.

Age Factors↗
PubMed1986

Endocrine and exocrine pancreatic function in treated coeliac disease.

Pancreatic function was assessed prospectively in a group of 18 treated adult coeliac patients, most of whom were asymptomatic. The para-aminobenzoic acid (PABA) test indicated exocrine pancreatic insufficiency in three patients, all of whom had persisting gastrointestinal symptoms. Arginine, 5 g intravenously, was used to stimulate pancreatic islet cells; basal and stimulated concentrations of plasma insulin, C-terminal glucagon, N-terminal glucagon, and blood glucose did not differ from asymptomatic nondiabetic control subjects. After gluten withdrawal, coeliac patients who responded clinically had no evidence of significant pancreatic impairment, but consideration of exocrine pancreatic insufficiency is worthwhile in those patients with persisting symptoms.

4-Aminobenzoic Acid↗
PubMed1986

Gastric emptying of a solid-liquid meal and gastro-intestinal hormone responses in patients with erosive oesophagitis.

Abnormal gastric motility has been recognised recently in some patients with excessive gastro-oesophageal reflux. The cause of this motility disturbance is unknown. A dual isotope study has been used to assess gastric emptying of solid and liquid components of a test meal in 16 patients with erosive oesophagitis and in 16 control subjects. The release of insulin, gastrin, pancreatic polypeptide, gastric inhibitory polypeptide and neurotensin in response to the test meal was monitored in all subjects. A significant delay in both solid and liquid emptying was observed in patients with erosive oesophagitis. However, they demonstrated no alteration in the pattern of hormone release in response to the test meal.

Adult↗
PubMed1986

Dietary history and nutritional state in treated coeliac patients.

The gluten content and nutritional adequacy of the diet of a group of adult coeliac patients supposedly following a gluten-free diet for at least one year were assessed. Results were considered in relation to the nutritional state of these patients, determined by anthropometric measurement, and the histological appearance of jejunal biopsies taken at the time of nutritional assessment. Imperfect gluten avoidance, mild malnutrition and mild histological abnormalities on jejunal biopsy were frequent findings. A careful dietary and nutritional assessment when considered in light of histological findings at jejunal biopsy helps to identify the causes of persisting symptoms or malnutrition in treated coeliac patients. A normal jejunal biopsy in a malnourished patient whose dietary compliance is good should prompt a search for an alternative diagnosis.

Adolescent↗
PubMed1986

Molecular mechanisms of ligand binding to opioid receptors: selective inhibition by ethanol?

Effects of varying concentrations of ethanol on the conformations of DAGO, a mu-specific opioid ligand were monitored by FT-IR spectroscopy. The binding of 3H-labeled DAGO (mu-agonist) and DSLET (delta-agonist) to opioid receptors in the presence of varying concentrations of alcohol was also determined. The results indicate that the conformational features of the ligands are altered and conformational factors may play a role in ligand-receptor interaction.

Animals↗
PubMed1986

Investigation of non-cardiac chest pain--which oesophageal test?

Five different tests were used to evaluate oesophageal function in 22 patients who presented to a cardiac unit with acute chest pain but whose cardiological investigations were negative. Eight patients had an abnormality on oesophagoscopy, 10 had an abnormal pH monitoring study, six had a positive acid infusion test, 10 had an abnormal manometric study and six had an abnormal oseophageal transit scintiscan. Concordance for the three tests of gastro-oesophageal reflux disease was low at 28%, and for the two tests of oesophageal motility only 55%. Only two patients had normal results in all five tests.

Adult↗
PubMed1985

Bile acid concentrations in the gastric juice of patients with erosive oesophagitis.

Intragastric total bile acid concentrations were measured before and after a corn oil test meal in 16 patients with erosive oesophagitis and symptoms of gastro-oesophageal reflux. Sixteen age and sex matched control subjects were also studied. No significant difference was detected between fasting or postprandial gastric bile acid concentrations in patients and in control subjects although a wide range of bile acid concentrations was detected among individuals in both groups. Gastric juice pH was less than 3.5 in seven patients when intragastric bile acid concentrations were greater than 200 mumol/l. These results do not support a role for abnormal duodenogastric reflux in the pathogenesis of erosive oesophagitis. The detection of acid reflux in such patients during intra-oesophageal pH monitoring, however, does not exclude the presence of bile acids which may contribute to the cytotoxic potential of gastric juice.

Adult↗
PubMed1985

Does age influence normal gastro-oesophageal reflux?

Prolonged oesophageal pH monitoring is being used increasingly to detect abnormal gastro-oesophageal reflux. To assess the influence of age on normal reflux patterns, a group of 13 young asymptomatic subjects (mean age 22 years) was compared with a group of 14 middle aged asymptomatic subjects (mean age 49 years). An ambulatory system using a radiotelemetry capsule and a portable receiving system was used, oesophageal pH being recorded for at least 16 hours during an overnight hospital stay under standardised conditions. There was no significant difference in the duration or frequency of reflux episodes as defined by pH less than 5, less than 4, less than 3, or as a fall in pH of more than two units. It is concluded that it is an acceptable practice to use young volunteers to establish normal values in reflux studies of young and middle aged patients.

Adult↗
PubMed1985

Oesophageal histology in reflux oesophagitis.

Multiple specimens taken at oesophageal suction biopsy were obtained from 56 patients, of whom 44 had symptoms of gastro-oesophageal reflux and 24 had endoscopic evidence of erosive oesophagitis. Biopsies were examined independently by two histopathologists for the following criteria for reflux: epithelial hyperplasia, vascular dilatation and congestion, neutrophil infiltration, and eosinophil infiltration. The incidence of these criteria in patients with and without endoscopic evidence of oesophagitis or symptoms of reflux was investigated. It was concluded that vascular dilatation and epithelial hyperplasia, defined as basal zone thickness greater than or equal to 15% and papillary elongation greater than or equal to 66%, can be detected most reliably, but their diagnostic accuracy is limited unless multiple biopsies are examined.

Adolescent↗
PubMed1985

Clinical presentation of coeliac disease in adult gastroenterological practice.

Clinical features, complications and results of investigations are analysed in 50 patients diagnosed by jejunal biopsy as having coeliac disease at the Adult Gastroenterology Unit, Royal Victoria Hospital, Belfast, between 1969 and 1983. Only one patient was entirely asymptomatic, but 22% had no disturbance of bowel habit, and 50% had not lost weight. There were relatively few physical abnormalities on clinical examination. Screening tests using standard haematological and biochemical methods were positive only in between 8% and 52% of patients. More specific tests for malabsorption were positive in between 54% and 84% of patients. Jejunal biopsy remains the definitive procedure to identify patients with coeliac disease.

Adolescent↗