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Biomedical subjects

J W Hamilton

Publications and source records attributed to J W Hamilton.

At least 91 records · Page 5Linked to original sources
PubMed1988

Sleeping on a wedge diminishes exposure of the esophagus to refluxed acid.

In a randomized crossover study, we compared the effect on gastroesophageal reflux of three sleeping positions: elevation of the head of the bed on standard eight-inch bed blocks; elevation by a foam wedge; or a flat position. Fifteen subjects with moderate to severe reflux symptoms were studied in each position on consecutive nights using continuous intraesophageal pH monitoring. We found no difference in reflux frequency among the positions. The wedge caused a statistically significant decrease in the time that distal esophageal pH was less than 4 as compared to the flat position. The wedge also decreased the longest episode experienced by the subjects. Elevation on blocks caused a similar improvement in parameters but failed in this study to achieve statistical significance. Both elevation by a wedge and on blocks showed a trend towards a decrease in clearance time as compared to the flat position. The patients did not always prefer elevation on a wedge, but for some it is a valuable alternative to elevation by bed blocks.

Aged↗
PubMed1988

Isolation of alligator gar (Lepisosteus spatula) glucagon, oxyntomodulin, and glucagon-like peptide: amino acid sequences of oxyntomodulin and glucagon-like peptide.

Oxyntomodulin, glucagon, and a glucagon-like peptide (GLP) have been isolated from the endocrine pancreas of the alligator gar (Lepisosteus spatula), a ganoid fish. The three peptides were isolated by gel filtration and HPLC and were identified by size, composition, and glucagon-like immunoreactivity. The amino acid sequences of the oxyntomodulin and GLP were determined. The oxyntomodulin contains 36 amino acid residues and its sequence is H S Q G T F T N D Y S K Y L D T R R A Q D F V Q W L M S T K R S G G I T. The composition of the glucagon is identical to the N-terminal 29 residues of the gar oxyntomodulin. The single form of GLP found contains 34 amino acid residues in the following sequence: H A D G T Y T S D V S S Y L Q D Q A A K K F V T W L K Q G Q D R R E. These findings suggest that all three peptides are derived from a common precursor.

Amino Acid Sequence↗
PubMed1988

A new technique and catheter design for assessing capacity and compliance characteristics of ileal reservoirs.

Ileal pouch reconstruction has become a preferred treatment for ulcerative colitis and familial polyposis in selected patients. Various pouch designs have been advocated with good functional results dependent upon preservation of excellent continence and a reasonable stool frequency pattern. Objective data are needed to recognize pouch designs that offer the best functional results. It is important to have a method of accurately measuring pouch volume and compliance characteristics of the pouch. We have described the construction and use of an inexpensive and easily assembled condom tipped catheter, which is useful for early and long term follow-up study of ileal pouch reconstructions.

Catheterization↗
PubMed1988

Human electrogastrograms: comparison of techniques of recording.

There are different methods for recording physiologic electrical signals cutaneously. Monopolar recording has been used, by us and by others, to record the basic electrical rhythm of the stomach. In an effort to improve our ability to routinely obtain a recording of the basic electrical rhythm of the stomach, using cutaneous electrodes (electrogastrography), we have investigated different electrode recording techniques, and compared them with monopolar recording. We studied 10 healthy asymptomatic volunteers who were fasting, using each of the techniques while simultaneously monitoring a monopolar electrogastrogram. Three different recording techniques were studied: a Wilson central terminal, comparing alternative placements of the reference electrodes; a Wilson central terminal with a single placement of the reference electrodes, but alternative placements of the active exploratory electrode; and, last, a differential recording technique. We found all of the studied techniques to be superior to monopolar recording in the amount of time a recognizable three/min basic electrical rhythm could be recorded. However, the differential recording arrangement yielded an improvement in percent of recording time so significant that the electrogastrographic signal could be visually discerned to greater than 80%, compared with 37%, of the monopolar recording. Thus, the differential recording technique is far superior for recording the electrogastrogram.

Electrodes↗
PubMed1987

Management of chronic ulcerative colitis and rectovaginal fistula by simultaneous ileal pouch construction and fistula closure. Report of a case.

Persistent rectovaginal fistulas occurring with ulcerative colitis are unusual manifestations that complicate surgical or medical treatment of the primary disease. Prior to the development of ileal pouch procedures, many cases were traditionally managed with a total colectomy and permanent ileostomy. The authors are aware of no previous study using concurrent fistula repair combined with ileal pouch construction to manage this complex problem. The successful simultaneous repair of a chronic rectovaginal fistula with ileal pouch reconstruction in a patient with intractable ulcerative colitis is reported.

Adult↗
PubMed1987

Isolation and structures of alligator gar (Lepisosteus spatula) insulin and pancreatic polypeptide.

Insulin and a 36-residue peptide with homology to pancreatic polypeptide (PP) were isolated from the endocrine pancreas of the alligator gar (Lepisosteus spatula), a ganoid fish, by gel filtration and HPLC. Heterologous radioimmunoassays were used to detect insulin-like and PP-like immunoreactivities during purification of the two peptides. The sequence of the 36-amino acid peptide containing a C-terminal tyrosinamide was identical at 31 of 36 positions to porcine neuropeptide Y (NPY). The amino acid sequence of this peptide is YPPKPENPGEDAPPEELAKYYSALRHYINLITRQRY-NH2. The second peptide, gar insulin, contains 52 amino acid residues and is composed of a 21-residue A chain and a 31-residue B chain. The sequence of the A chain is GIVEQCCHKPCTIYELENYCN. The sequence of the B chain is AANQHLCGSHLVEALYLVCGEKGFFYNPNKV.

Amino Acid Sequence↗
PubMed1987

gamma-Glutamyltransferase activity in atypical acinar cell nodules of rat pancreas.

The biochemical and histochemical measurement of the enzyme gamma-glutamyltransferase (GGT) was undertaken in normal rat pancreas and in rat pancreas containing azaserine-induced preneoplastic nodules. A steady decrease in pancreatic GGT activity was observed in the normal animals as they aged from 5 to 34 weeks. The azaserine-induced nodules contained a lower average GGT activity than the control pancreas although a 10-fold variation was noted in the GGT activity of individual nodules. A significant increase in concentrations of both reduced glutathione and oxidized glutathione was noted in pancreatic nodules from azaserine-treated rats compared to concentrations found in both control pancreas from untreated rats and internodular pancreas from azaserine-treated rats. A pancreatic acinar cell carcinoma contained low GGT activity--similar to that found in large nodules and about 10% of the level found in control pancreas. Pancreatic GGT levels were higher in 5- and 7-week-old rats fed chow than in rats fed a purified diet, but this effect of chow was not observed at 34 weeks of age. Feeding a purified diet supplemented with a retinoid, N-2-hydroxyethylretinamide (2-HER), for a period of 2 weeks did not influence the GGT activity level in either normal pancreas or in the azaserine-induced nodules. While decreased GGT activity does not serve as a marker for all atypical acinar cell nodules, deficient activity with concomitant increased glutathione levels appears to correlate generally with increased growth potential.

Animals↗
PubMed1987

Eugene O'Neill and Addison's disease.

A detailed review of hospital records, physician's notes, diaries, letters, and autopsy reports offers sufficient clinical grounds to establish that Eugene O'Neill developed adrenal insufficiency, secondary to tuberculosis, in later life--a fact hitherto unknown--the condition not becoming manifest until after he had abdominal surgery in 1936.

Addison Disease↗
PubMed1987

Quadruple-loop (W) ileal pouch reconstruction after proctocolectomy: analysis and functional results.

This report analyzes experience with a modified four-limb W-shaped ileal pouch that has a larger initial capacity than do J- or S-shaped pouch designs. Fifteen patients (median age: 35 years) underwent W pouch reconstruction after proctocolectomy for ulcerative colitis and familial adenomatous polyposis. Follow-up on each patient averaged 14 months (range: 6 to 24 months). All procedures were performed without death and with minimal morbidity. Assessment of functional results showed 24-hour stool frequency (mean +/- SEM) decreasing from 6.0 +/- 0.39 initially to 4.8 +/- 0.43 at 1 year (p less than 0.005). Night evacuation decreased from 1.1 +/- 0.2 at 1 month after surgery to 0.25 +/- 0.12 at 1 year (p less than 0.025), with 10 of 15 patients having no nocturnal pouch evacuation. Continence was excellent in all patients with the exception of three of 15 patients who had occasional minimal nighttime seepage. Pouch volume determined at surgery by saline solution infusion was 200 +/- 21 ml. Pouch volume and compliance (pressure/volume) were measured before ileostomy closure and at 6 months after surgery via a special pressure-monitored balloon catheter. Maximal pouch volume increased from 190 +/- 21 ml (at time of ileostomy takedown) to 470 +/- 85 ml at 6 months. Ileal reservoir construction with a W pouch design resulted in a low 24-hour and nighttime stool frequency and excellent compliance and evacuation characteristics.

Adenomatous Polyposis Coli↗
PubMed1987

Balloon dilation for the treatment of stomal stenosis complicating gastric surgery for morbid obesity.

In a retrospective analysis, we evaluated our results with endoscopic dilation of enterostomy stenoses that complicated gastric procedures performed for the treatment of morbid obesity. Of 541 patients who underwent a gastric procedure for treatment of morbid obesity, we found 19 patients in whom endoscopic dilations of stenoses had been attempted. We also include three patients who had surgery elsewhere but who underwent dilations at our institution. Fourteen had stenoses complicating gastric bypass with Roux-en-Y anastomoses, and eight had stenoses complicating a gastroplasty (gastrogastrostomy). Two different types of dilation were attempted during the interval reviewed--Fogarty balloon dilations and Grüntzig balloon dilations. None of the eight patients with gastroplasties benefited from the attempted dilation, but 10 of the 14 patients with stenoses complicating gastric bypasses have done well. We found no significant difference between Fogarty and Grüntzig balloon dilations. We conclude that balloon dilation is an effective means of treating stenosis that complicates gastric bypass performed with Roux-en-Y anastomoses in cases of morbid obesity.

Adult↗
PubMed1986

Structure of a peptide from coho salmon endocrine pancreas with homology to neuropeptide Y.

The amino acid sequence of a peptide isolated from the Pacific salmon (Oncorhynchus kisutch) endocrine pancreas has been determined. This simple 36 residue peptide is a member of the pancreatic polypeptide family. It contains a C-terminal tyrosinamide and is more homologous with porcine neuropeptide Y (NPY) (83%) and peptide YY (75%) than any of the previously characterized pancreatic polypeptides (PP). This peptide appears to be the major but not the only representative of this family of peptides present in the endocrine pancreas of this fish. This peptide is referred to as salmon pancreatic polypeptide (salmon PP).

Amino Acid Sequence↗
PubMed1986

Formation and secretion of fragments of parathormone. Identification of cleavage sites.

Monolayer cultures of bovine parathyroid cells or fresh gland slices were incubated with radioactive amino acids in order to study the formation and metabolism of parathormone (PTH). PTH, secretory protein I, and COOH-terminal fragments of PTH were all released into media within 30 min, most strongly in the first hour after synthesis. Peptides in tissue, cells, and media were separated using reverse-phase high performance liquid chromatography. In eluates of media, six radioactive peaks were prominent. The first four and the sixth were immunoreactive in a COOH-terminal specific PTH radioimmunoassay, but only the sixth was reactive in an NH2-terminal specific assay. Under conditions where recovery of PTH(1-34) was quantitative, gel filtration of media was used to show that no NH2-terminal fragments of PTH were secreted. Sequence analyses of secreted COOH-terminal peptides indicated that the NH2 termini of the first three peaks corresponded to residues 43, 37, and 34 of PTH. The fourth peak contained a mixture of two peptides with NH2 termini at residues 24 and 28 of PTH. The fifth could not be identified; the sixth was PTH. Cleavages at the 23-24 bond of PTH occurred within minutes of the formation of PTH itself, and the other peptides were formed more slowly. Mandatory cleavage of PTH at the 23-24 peptide bond would destroy the biological activity of the hormone on kidney and bone, a situation consistent with the possibility that intracellular PTH metabolism participates in secretory regulation. The results showed that different peptides were generated in parathyroid cells than were previously shown to be produced by cathepsin B or D. The results suggest that the proteolytic pathway which results in the secretion of PTH fragments is nonlysosomal in nature.

Amino Acid Sequence↗
PubMed1986

Ah receptor for 2,3,7,8-tetrachlorodibenzo-p-dioxin: ontogeny in chick embryo liver.

Aryl hydrocarbon hydroxylase (AHH, cytochrome P1-450) is induced in chick liver very early during embryonic development if embryos are treated with 3-methylcholanthrene-type compounds such as 3,4,3'4'-tetrachlorobiphenyl. In mammals, AHH induction is known to be mediated by the Ah receptor. Liver from embryonic and newly hatched chicks was found to contain a cytosolic receptor for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) which has properties that are very similar to properties of the Ah receptor previously characterized in mammalian tissues. In chick embryo liver, cytosolic binding sites for TCDD were of high affinity (Kd for [3-H]-TCDD = 0.2 nM) and were specific for 3-methylcholanthrene-type inducers. The specific binding component sedimented at about 9S on sucrose density gradients prepared at low ionic strength. A high level of Ah receptor was detected in chick embryo liver by the fifth day of incubation (5 DI); this is at least 24 hours prior to the onset of AHH inducibility. The Ah receptor concentration increased from 5 DI to 8 DI, the period when chick liver is undergoing early morphological differentiation. After 8 DI, Ah receptor levels dropped substantially and remained low into the posthatching period. In contrast, AHH inducibility was high by 7 DI and remained high throughout embryonic development and into the posthatching period. The discrepancy between Ah receptor levels and the degree of AHH inducibility suggests that only a small fraction of the Ah receptor population is required for maximal AHH induction.

Animals↗
PubMed1986

Symptomatic ectopic gastric epithelium of the cervical esophagus. Demonstration of acid production with Congo red.

Four patients were found with patches of gastric fundal type epithelium just distal to the cricopharyngeus, separated from the gastroesophageal junction by 15-20 cm of normal squamous epithelium. Three of the four had symptoms of dysphagia localized to the area of the esophagus containing the epithelium. Congo red dye (a pH indicator) applied to the mucosa during endoscopy revealed acid production by the mucosa after stimulation with pentagastrin. Interestingly, the patients' symptoms decreased during treatment with cimetidine only to return on cessation of therapy.

Adult↗
PubMed1986

Human electrogastrograms. Comparison of surface and mucosal recordings.

A method to record the gastric basic electrical rhythm (BER) using skin electrodes is described. Correlation is made with mucosal suction electrodes in 20 volunteers. Successful simultaneous recording from surface electrodes and mucosal electrodes is made in 16/20 subjects (80%). An increase in amplitude of the recorded gastric BER with gastric contractions is demonstrated and discussed. Five patients with gastric motility disturbances and chronic nausea are also investigated. Four of these patients had diabetic gastroparesis. Each had preservation of the gastric BER. The rate was usually normal at three per minute, but during acute nausea episodes which occurred in three of the four, an abnormally increased rate of the BER (tachygastria) was seen. This finding was also seen in a subject with atrophic gastritis and delay of gastric emptying. The surface electrogastrogram may prove to be a useful tool for the investigation of patients with suspected gastric arrhythmias.

Abdominal Muscles↗