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M Gregor

Publications and source records attributed to M Gregor.

At least 109 records · Page 6Linked to original sources
PubMed1991

Evaluation of endosonography in sclerotherapy of esophageal varices.

During intravariceal sclerotherapy of esophageal varices with polidocanol in 32 patients with portal hypertension due to liver cirrhosis of various etiologies, endosonographic assessment of both esophageal and gastric intramural vessels was carried out in order to evaluate the usefulness of endosonography in the follow-up of the variceal status. In all cases endosonography demonstrated esophageal and gastric varices; in contrast, only five cases of gastric varices could be demonstrated by endoscopy. Furthermore, different stages of variceal obliteration following sclerotherapy could be demonstrated by means of endosonography, and it was possible to identify incomplete obliteration in about one-third of the patients in whom inadequate sclerotherapy was suspected endoscopically. In addition, the status of gastric varices during sclerotherapy was demonstrated by means of endosonography. Only in cases of adequate sclerotherapy of esophageal varices, as assessed by both endoscopic and endosonographic criteria, were gastric varices plugged. On the basis of these findings endosonography would appear to be a useful technique for the diagnosis and follow-up of esophageal and gastric varices during intravariceal sclerotherapy.

Esophageal and Gastric Varices↗
PubMed1990

Endosonographic appearance of the esophagus in achalasia.

Primary motility disorders of the esophagus require the exclusion of intramural tumors. The procedures currently used for the differential diagnosis of achalasia such as endoscopy with biopsy, esophageal and gastric radiography, abdomino-thoracic computed tomography and intraluminal esophageal manometry, are unsatisfactory when a tumor growing intramurally is suspected. A more recent method of studying the integrity of the gastrointestinal wall and its surrounding tissue is endoscopic ultrasonography. In 16 patients suspected of having achalasia, endosonography was performed in addition to the above-mentioned conventional examinations. Fifteen of them showed a normal ultrasonic structure of the wall of the gastro-esophageal junction, with no sign of hypertrophy of the smooth muscle layer. In the remaining case endoscopic ultrasonography was able to detect an intramural tumor, as evidenced by the inhomogeneous ultrasonic structure of the esophageal wall. Computed tomography and all the other conventional diagnostic procedures used failed to demonstrate this tumor. In conclusion, the findings presented strongly suggest that endosonography can contribute to the differential diagnosis of achalasia and intramural tumors.

Adult↗
PubMed1990

The role of gut-glucagon-like immunoreactants in the control of gastrointestinal epithelial cell renewal.

In vitro and in vivo studies have provided considerable information on the possible physiologic function of circulating gastrointestinal hormones as well as locally acting regulatory peptides in the multifactorial control of adaptive gastrointestinal epithelial cell proliferation and cell renewal. It has been suggested by circumstantial evidences that enteroglucagon (EG; G-GLI I) may act as a trophic factor on the intestinal mucosa which may account for adaptive changes of the small intestine following various stimuli. However, we have shown that there are experimental conditions (germ-free rats after conventionalisation; jejunal self-filling blind loops) in which intestinal hyperplasia does not correspond to an increase in the concentrations of enteroglucagon in plasma or intestinal mucosa. Furthermore, despite a continuous immunoneutralisation of circulating endogenous enteroglucagon by monoclonal antibodies there was an adaptive, hyperplastic response of the ileal remnants after a 70% proximal small bowel resection which was of the same magnitude as in the control group but was even greater considering the increased number of mitoses per crypt. In order to gain additional insight into the putative role of enteroglucagon as an enterotrophic regulatory peptide, an in vitro model was used to investigate the effect of highly purified rat G-GLI I on the proliferative response of primary small intestinal epithelial cells of fetal rats. Whereas there was a well known growth-promoting action of EGF, the proliferation of rat fetal intestinal epithelial cells was inhibited by the addition of purified G-GLI I. These results indicate that enteroglucagon does not act as an enterotrophic factor but provide the first direct evidence consistent with an antitrophic role of enteroglucagon in the small intestine.

Adaptation, Physiological↗
PubMed1989

[Abdominal colic].

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Abdomen, Acute↗
PubMed1988

[Endosonographic findings of benign and malignant lesions in the stomach wall. A prospective comparison with conventional imaging study procedures].

The results of endoscopic ultrasonography in the diagnosis and differentiation of benign and malignant lesions of the stomach was prospectively compared with those obtained by upper endoscopy with biopsy, double-contrast radiography and computed tomography in 15 patients with benign and 26 with malignant gastric lesions. The validity of the methods was established by comparing the results obtained with the long-term course observed clinically in conjunction with an endoscopic-histological follow-up or with the findings on histopathological examination of the operative specimen. Precise diagnosis of the lesion was made by endoscopic ultrasonography in about 90% of cases, a result better than that obtained with radiography or computed tomography. Furthermore, endoscopic ultrasonography had good sensitivity for demonstrating perigastric lymph node enlargement; in this respect it was better than computed tomography, but was not able to distinguish whether the enlargement was benign or malignant: this will only become possible with technical improvement of the instruments.

Adenocarcinoma↗
PubMed1988

Electroencephalographic sleep profiles in recurrent depression. A longitudinal investigation.

The electroencephalographic sleep profile of a group of recurrent depressives who had been depressed for less than four weeks was compared with their sleep profile in a prior episode of depression. The findings in these 19 cases indicate that early in the episode, rapid eye movement (REM) sleep findings are more abnormal, including shortened REM latency, REM sleep percent, and REM activity. Other sleep variables, such as sleep continuity measures and decreased delta-wave sleep, are abnormal in a similar fashion in both episodes. The results are not explainable on the basis of clinical severity or number of episodes and call for increased attention to the potential relationships between the psychobiological pattern and duration and course of the depressive episode.

Adult↗
PubMed1987

[Campylobacter pylori in the stomach, duodenum and colon of gastroenterological patients. An epidemiologic study of 120 subjects].

In a prospective study of 120 gastroenterological patients in Berlin, Germany, the prevalence of Campylobacter pylori was determined. When the gastric mucosa was normal, the prevalence was one in 19 patients (5.3%). In 101 patients with chronic gastritis it was cultured in 55 (54.5%). In 31 patients with chronic atrophic gastritis the organism was cultured in 25 (81%); in 60 patients with severe gastritis it was present in 75%, in 35 with moderate or severe chronic active gastritis in 82.8%. The diagnosis of gastric ulcer (9) or duodenal ulcer (12) was associated with the isolation of Campylobacter pylori in 55.6 and 91.7%, respectively. The prevalence of this organism in antral mucosa of this group of patients thus corresponds to that in Australia, England and North America. The organism was also demonstrated in the duodenum of 10 among 25 patients examined. But in none of 25 patients was it demonstrated in the sigmoid colon.

Berlin↗
PubMed1987

Immunocytochemical characterization of glucagon-immunoreactive cells using monoclonal antibodies to pancreatic glucagon.

Monoclonal antibodies raised to pancreatic glucagon were tested for their ability to detect glucagon-containing endocrine cells in material processed for light and electron microscopy. Samples from man, baboon and rat were used in this investigation. Two antibodies were specific for the pancreatic islet A cells, the remainder detected both pancreatic and enteric endocrine cells. In man and baboon the glucagon-containing cells were confined to the pancreas, lower small intestine and colon. In the rat the distribution was extended to include the corpus of the stomach and the jejunum. The cells identified in the ileum and colon were of three morphological types endocrine, paracrine (type 1) with a single basal process and paracrine (type 2) with multiple small cytoplasmic processes. These antibodies also detected cells in material fixed by conventional methods for electron microscopy. The ultrastructural appearance of the baboon pancreatic glucagon-containing ultracellular secretory granules were demonstrated to be clearly distinct from those described previously in man and rat. The secretory granules averaged 330 +/- 23 nm and lacked the characteristic clear outer halo seen in the other two species.

Animals↗
PubMed1987

Aneurysm of the right ovarian vein--an unusual cause of pulmonary embolism.

This case reports a 23-year-old female who experienced a massive bilateral pulmonary embolism. The source of thrombi was found to be in a large saccular aneurysm of the right ovarian vein. The pulmonary emboli were treated by local infusion of streptokinase. The patient was cured after removal of the aneurysm by surgery.

Aneurysm↗
PubMed1987

Morphologic and physiologic studies of canine ileal enteroglucagon-containing cells in short-term culture.

Enteroglucagon-containing cells have been maintained in short-term culture, and the morphologic characteristics of these cells and their response to selected agents have been determined. After 48 h in culture the ultrastructural appearance of the enteroglucagon-immunoreactive cells showed evidence of polarization with re-formation of apical microvilli and the secretory granules concentrated at the opposite pole of the cell. The size of the intracellular secretory granules was 370 +/- 15 nm. The release of enteroglucagonlike immunoreactivity was stimulated in a dose-dependent manner by the adrenergic agonists epinephrine and isoproterenol. The response to epinephrine was competitively inhibited by propranolol, producing a rightward shift of the dose-responsive curve. The alpha-adrenergic agonists methoxamine and clonidine did not stimulate enteroglucagon release above basal. The adenyl cyclase activator forskolin also stimulated release of the peptide in a dose-dependent manner. Carbachol and somatostatin produced a dose-dependent inhibition of epinephrine-stimulated release, indicating direct inhibitory modulation of enteroglucagonlike immunoreactive cells. Somatostatin also inhibited forskolin-stimulated release. These data indicate that canine ileal enteroglucagon cells in short-term culture respond to a number of specific stimuli.

Animals↗
PubMed1987

Effect of monoclonal antibodies to enteroglucagon on ileal adaptation after proximal small bowel resection.

On the basis of circumstantial clinical and experimental evidence, it has been suggested that enteroglucagon (EG) may act as an enterotrophic factor. This study was undertaken to evaluate the effects of long term in vivo immunoneutralisation of EG, using monoclonal antibodies to EG, on the hyperplastic ileal response after small bowel resection. Nineteen rats had a 70% proximal resection. A group of 10 rats was given iv 0.5 ml of undiluted hybridoma ascites immediately after the operation and on the 7th day postoperatively. Furthermore 0.025 ml/day of the same hybridoma ascitic fluid was continuously delivered ip for 14 days via mini-osmotic pumps. The hybridoma ascites was prepared from the clone 23.6B4 synthesising a monoclonal antibody directed toward the N-terminal to central region of the glucagon molecule which showed a marked crossreaction with EG. A control group of 9 rats was given a corresponding amount of antibody-free plasmacytoma ascites (Ag 8.653) by the same technique. Seven and 14 days postoperatively there was a plasma anti-EG-antibody excess with an excess binding capacity of 84.9 glucagon eq nM and 88.5 glucagon eq nM respectively. The three dimensional architecture and the proliferative activity of the ileal remnant were evaluated two weeks postoperatively. Despite a continuous immunoneutralisation of circulating endogenous EG by monoclonal antibodies, the adaptive response of the ileal remnants was of the same magnitude as that seen in the control group. These data do not support the hypothesis that EG is a circulating enterotrophic regulatory peptide.

Adaptation, Physiological↗
PubMed1987

Somatostatin and muscarinic inhibition of canine enteric endocrine cells: cellular mechanisms.

Using a recently developed canine primary enteric endocrine cell culture system, we have investigated the role of adenosine 3',5'-cyclic monophosphate (cAMP) in mediating the release of neurotensin and enteroglucagon. Epinephrine-stimulated peptide release was concomitant with an increase in cAMP accumulation. Carbachol and somatostatin (SRIF) markedly inhibited the epinephrine effect on both peptide release and cAMP content. The addition of 3-isobutyl-1-methylxanthine potentiated epinephrine-stimulated peptide release without altering the relative inhibition by carbachol and SRIF, suggesting that these agents did not inhibit endocrine cell function by increasing phosphodiesterase activity. To determine the role of cAMP production in mediating inhibition of peptide release, cells were incubated with the bacterial toxin, pertussis toxin (PT). In cultures pretreated with PT, carbachol inhibition of both peptide release and cAMP accumulation was completely reversed. In contrast, SRIF inhibition of cAMP content was completely reversed after PT treatment, but inhibition of peptide release was only partially reversed. Additionally, toxin treatment only partially reversed SRIF inhibition of forskolin- and calcium ionophore-stimulated peptide release. These data suggest that muscarinic cholinergic inhibition of neurotensin and enteroglucagon release is mediated entirely through the guanine nucleotide-binding protein (Ni) or a similar toxin-sensitive, GTP-binding protein. SRIF-inhibited peptide release is mediated partially through a toxin-sensitive substrate, as evidenced by PT reversal of reduced cAMP levels. SRIF may also inhibit neurotensin and enteroglucagon release by a cAMP-independent pathway that is not coupled to Ni or a similar PT-sensitive, GTP-binding protein.

1-Methyl-3-isobutylxanthine↗