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P E O'Brien

Publications and source records attributed to P E O'Brien.

At least 73 records · Page 4Linked to original sources
PubMed1990

Evaluation of putative cytoprotective properties of antiulcer drugs using quantitative histological techniques.

The capacity for cytoprotection has been claimed for a number of drugs that may have a place in the treatment of peptic ulcer disease. In this study we have used quantitative histological criteria to evaluate the ability of these drugs to be cytoprotective and have compared their effects with that of natural prostaglandin E2 (PG). The standard rat model, with injury by instillation of 1 ml of absolute ethanol, has been used. Putative cytoprotective agents were administered 15 min prior to ethanol. Each animal was sacrificed 15 min after ethanol exposure. The stomach was removed and studied using an established quantitative histological technique. This technique provides a measure of the surface area of mucosa damaged and of the volume of mucosa damaged. Ethanol alone caused damage to 76% of the area of the rat stomach and 14% of the volume of the rat gastric mucosa. Pretreatment by PG (25 micrograms/ml) resulted in reduction of the area of damage to 45% and reduction of the percentage volume damage to 2.2%. The synthetic analog of PGE2, Enprostil (1 microgram/ml) achieved similar protective effects. With pretreatment with colloidal bismuth subcitrate (10 mg/kg) or sucralfate (25 mg/kg), no protection against the surface area damaged by ethanol was seen, but there was a marked reduction of the volume of mucosa damaged. Indomethacin pretreatment augmented the damage caused by ethanol. The protective effects of colloidal bismuth subcitrate and sucralfate were not blocked by pretreatment with indomethacin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Gastric surgery for morbid obesity. The Adelaide Study.

The efficacy of three gastric restriction operations were compared in a prospective randomized study of 310 morbidly obese subjects. The median patient age was 34 years (range, 18 to 62 years). They were predominantly female (13:1) and had a median pre-operative weight that was 198% of their ideal weight (range, 160% to 318%). There was an equitable dispersion of perceived risk factors between the groups under study and there were no deaths during the perioperative period. Compliance with follow-up at 3 years was 91%. When success was defined as a loss of more than 50% of excess weight or a current pregnancy, the success rates at 3 years were 17% for gastrogastrostomy, 48% for vertical gastroplasty, and 67% for Roux-en-Y gastric bypass (p less than 0.001). Although the gastric bypass operation took longer to perform, there were similar outcome patterns for the three groups during the postoperative period. We conclude that the Roux-en-Y gastric bypass is the preferred procedure for the surgical treatment of morbid obesity.

Adult↗
PubMed1987

Abnormalities of peptide-containing nerve fibers in infantile hypertrophic pyloric stenosis.

The distributions of nerve cells and fibers with immunoreactivity for the peptides enkephalin, gastrin-releasing peptide, neuropeptide Y, somatostatin, substance P, and vasoactive intestinal peptide were examined in specimens of myenteric plexus and external muscle from the pylorus of 20 infants with hypertrophic pyloric stenosis. These were compared with peptide distributions in pyloric samples from unaffected infants and adults. In the normal pylorus the circular muscle was richly supplied with fibers reactive for enkephalin, neuropeptide Y, substance P, and vasoactive intestinal peptide. In pyloric stenosis, these immunoreactive fiber bundles were either missing or less than 5% of normal. In contrast, there were reactive cell bodies and nerve fibers in the myenteric plexuses of both normal and affected specimens. In the samples from cases of stenosis, swollen nerve fibers that appeared to be in the process of degeneration were frequently encountered. It is concluded that infantile hypertrophic pyloric stenosis is associated with a loss of peptide immunoreactivity in nerve fibers in the circular muscle, although the same peptides are still revealed in fibers and in nerve cell bodies in the myenteric plexus.

Enkephalin, Leucine↗
PubMed1987

Distributions of neuropeptides in the human esophagus.

The distributions of nerve cells and fibers with immunoreactivity for the peptides substance P, somatostatin, enkephalin, vasoactive intestinal peptide, gastrin-releasing peptide, and neuropeptide Y and the enzyme tyrosine hydroxylase were examined in 25 samples of human esophagus. These were compared with samples of stomach and intestine. In the smooth muscle of the muscularis externa, the muscularis mucosae, and beneath the epithelium, the most abundant nerve fibers contained vasoactive intestinal peptide and neuropeptide Y, in contrast to the scarcity of substance P, enkephalin, somatostatin, and gastrin-releasing peptide. Gastric and intestinal samples contained dense populations of fibers containing vasoactive intestinal peptide, neuropeptide Y, substance P, and enkephalin in the equivalent layers, but somatostatin- and gastrin-releasing peptide-immunoreactive fibers were scarce. Complete coexistence of vasoactive intestinal peptide and neuropeptide Y in nerve fibers within the muscle layers was demonstrated in the esophagus, but not in gastric and intestinal samples. The myenteric plexus along the length of the esophagus contained cell bodies and fibers reactive for vasoactive intestinal peptide, neuropeptide Y, enkephalin, and substance P. Somatostatin-immunoreactive cell bodies were very rare in the myenteric plexus, no gastrin-releasing peptide-immunoreactive cell bodies were seen, and both somatostatin and gastrin-releasing peptide-immunoreactive fibers were rare. In the upper esophagus, striated muscle bundles did not contain nerve fibers reactive for these peptides but immunoreactive fibers were seen in the muscularis mucosae and subepithelium. It is concluded that the esophagus has a different pattern of innervation by peptide-containing neurons than the stomach and intestines. Esophageal neurons can be classified into separate classes on the basis of their peptide content.

Adult↗
PubMed1987

Management of diffuse peritonitis by prolonged postoperative peritoneal lavage.

Prolonged postoperative peritoneal lavage has been used as a part of the management of 55 patients with diffuse peritonitis. The lavage technique consisted of 60 min cycles of instillation and drainage of a lavage fluid into the peritoneal cavity via a peritoneal dialysis catheter. The lavage fluid was a slightly hypertonic salt solution containing antibiotics, usually cefotaxime and metronidazole. The overall mortality rate in the series was 11% (6/55). Only one of these patients had residual abdominal sepsis present at post-mortem, the remaining deaths being due to a progression of the pre-existing disease. Five patients showed evidence of further intra-abdominal sepsis. In three of these patients this was associated with the presence of a previously well established abscess cavity. The overall results indicate that, for this group of patients recognized to be at high risk of mortality or further sepsis, the use of prolonged postoperative peritoneal lavage is associated with an improved outcome.

Adolescent↗
PubMed1984

On the possible role of prostaglandin E2 in intestinal stasis in the gastric brooding frog Rheobatrachus silus.

Responses of isolated intestinal preparations from the anurans Bufo marinus and Limnodynastes tasmaniensis to various agents have been studied, as models for the intestinal stasis reported in the rare gastric brooding frog, Rheobatrachus silus. It is inferred from the responses that the preparations possessed excitatory muscarinic and histamine receptors and inhibitory adrenergic receptors, conforming to the typical vertebrate pattern. The circular muscle was unresponsive to prostaglandin E2, whereas longitudinal muscle relaxed to prostaglandin E2. Some of the longitudinal preparations exhibited a biphasic response to arachidonic acid, i.e. contraction followed by relaxation. Indomethacin prevented the relaxation phase, indicating that the intestine synthesised a prostaglandin E-like substance from arachidonic acid. These results draw attention to the possibility that PGE2 may be responsible for the intestinal stasis associated with gastric brooding in the gastric brooding frog.

Animals↗
PubMed1984

Substance P-containing nerves in the human small intestine. Distribution, ultrastructure, and characterization of the immunoreactive peptide.

Light and electron microscopic immunocytochemical techniques were used to examine the distribution and ultrastructure of substance P-immunoreactive nerves in human jejunum and distal ileum. The organization of human enteric substance P-containing nerves closely resembled that in other species. Dense arrays of varicose immunofluorescent fibers occurred in myenteric and submucous ganglia (which contained immunoreactive nerve cell bodies) and in the mucosa. There were fibers in both muscle layers, in the muscularis mucosae, and around blood vessels. Fibers in the myenteric plexus contributed to both ascending and descending pathways. Substance P-immunoreactive axon profiles contained small round and large round vesicles and were apposed to nerve cell bodies, and nonimmunoreactive and immunoreactive axon profiles. Synapselike contacts were occasionally observed on nerve cell bodies and processes. The substance P-like material was characterized by high pressure liquid chromatography and radioimmunoassay and found to be indistinguishable from the authentic undecapeptide. These results suggest that enteric nerves containing substance P may play similar roles in humans as in other species.

Adult↗
PubMed1984

Noradrenergic nerves in human small intestine. Distribution and ultrastructure.

Noradrenergic nerves in human jejunum and distal ileum were identified at the light microscopic level by fluorescence histochemistry and at the ultrastructural level by 5-hydroxydopamine loading in vitro and by the chromaffin reaction. The myenteric and submucous ganglia contained dense arrays of varicose noradrenergic fibers; the muscularis externa, muscularis mucosae, intestinal glands, and villi were sparsely supplied. Enteric axon profiles that had taken up 5-hydroxydopamine contained variable proportions of flattened, small round, and pleomorphic large vesicles all containing electron-dense material. Chromaffin-reactive enteric axon profiles and some enteric profiles in conventionally fixed untreated intestine contained similarly shaped vesicles. After 5-hydroxydopamine loading, noradrenergic nerves supplying blood vessels contained large round and small round vesicles with dense cores. Noradrenergic varicosities were concentrated near the edges of myenteric ganglia and were randomly distributed in submucous ganglia. Noradrenergic axons occasionally formed synapses on nerve processes in both myenteric and submucous ganglia, and on rare occasions, on nerve cell bodies in myenteric ganglia. Nonnoradrenergic axon profiles containing small round vesicles with granular inclusions (ring vesicles) were also found in human small intestine. The distribution and ultrastructure of noradrenergic nerves in human small intestine is similar to that in other mammals except for the occurrence of synapses in human ganglia.

Adrenergic Fibers↗
PubMed1983

Patient well-being after gastric bypass surgery for morbid obesity.

The physical and psychosocial consequences of gastric bypass surgery were observed in 30 morbidly obese patients. Twenty-seven of these patients were satisfied with the results of surgery. Satisfaction was associated with improved health, a better self-image, and greater social activity. Dissatisfaction occurred when an appreciable amount of weight was not lost, or when the patient's expectations about the results of surgery were unrealistic.

Adult↗
PubMed1975

Effect of gastric secretory inhibitors on the gastric mucosal barrier.

The effects of the synthetic prostaglandin 16, 16 dimethyl-E2 methyl ester (16-diMe-PGE2) and the histamine H2-receptor antagonist metiamide on the gastric mucosal barrier have been studied using the Heidenhain pouch dog model. The 16-diMe-PGE2 caused significant change in the ionic permeability of the mucosa when instilled into the pouch in a concentration of 300 mug/20 ml. Intravenous administration of 16-diMe-PGE2 did not alter the barrier nor did it alter the response of the mucosa to sodium taurocholate. Metiamide given into the pouch did not affect the mucosa barrier and the response to taurocholate was not affected when metiamide was given locally or intravenously.

Animals↗
PubMed1971

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Allied Health Personnel↗