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Biomedical subjects

M J Collen

Publications and source records attributed to M J Collen.

At least 55 records · Page 3Linked to original sources
PubMed1989

Abdominal pain in hereditary angioedema: the role of acid hypersecretion.

Hereditary angioedema is a familial disorder characterized by recurrent episodes of soft tissue swelling and abdominal pain. Whereas most patients are successfully treated with androgenic steroids, some have abdominal pain unresponsive to therapy. To determine whether acid-peptic disease could account for the abdominal pain unresponsive to androgen therapy, we performed upper gastrointestinal endoscopy and determined basal acid output in 21 consecutive patients with hereditary angioedema and abdominal pain. Mean basal acid output of this group was 6.0 +/- 5.9 mEq/h, with five patients having gastric acid hypersecretion (defined as a basal acid output of greater than 10.0 mEq/h). The abdominal pain in 18 responded to stanozolol, whereas the pain in three patients did not change. Acid-peptic mucosal disease (esophagitis or duodenal ulcer) was present in these three patients with abdominal pain unresponsive to androgen therapy, all of whom had gastric acid hypersecretion (basal acid outputs of 13.7, 19.1, and 21.5 mEq/h, respectively). These three patients were treated with ranitidine but required increased doses to control their gastric acid hypersecretion, and to promote complete relief of abdominal pain and healing of their esophagitis or ulcer disease. These results indicate that there is a subset of patients with hereditary angioedema whose abdominal pain may be secondary to acid-peptic disease and gastric acid hypersecretion. Such individuals may require increased therapeutic doses of antisecretory medication to promote complete healing of esophagitis or ulcer disease. Basal acid output and upper gastrointestinal endoscopy are important determinants when evaluating abdominal pain in patients with hereditary angioedema that fails to respond to standard therapy.

Abdomen↗
PubMed1989

Hyperplastic colonic polyps as a marker for adenomatous colonic polyps.

Hyperplastic colonic polyps are generally regarded as being of little or no clinical consequence. Recently, however, hyperplastic polyps have been found to share numerous functional similarities with colorectal carcinoma. To determine whether the presence of an isolated left-sided colonic hyperplastic (metaplastic) polyp could serve as a marker for more proximal synchronous adenomatous colonic polyps, we retrospectively analyzed all consecutive colonoscopic polypectomies performed over an 18-month period at two medical centers. It is the policy at both institutions to remove or biopsy all polyps, regardless of size. Indications for colonoscopy included known or previous colonic polyps or carcinoma, hemoccult positive stool, lower gastrointestinal bleeding, iron deficiency anemia, abnormal barium enema, inflammatory bowel disease, abdominal pain, and family history of colon cancer. The location of adenomatous polyps and hyperplastic polyps was recorded and compared. One hundred sixty-three of 845 consecutive patients (19.3%) had at least one colonic polyp. The prevalence of adenomatous polyps alone was 10.3%, hyperplastic polyps 9%, and both types 1.9%. The prevalence rate for an adenomatous polyp in patients without a hyperplastic polyp was 15%. In contrast, among patients with a hyperplastic polyp, 49% had a synchronous adenomatous polyp. Only 3.4% of patients had an adenomatous polyp proximal to the splenic flexure when no polyps were present in the left colon. Conversely, among the 29 patients in whom an isolated hyperplastic polyp was found in the left colon, there was a 32.5% prevalence of adenomatous polyps in the proximal colon (p less than 0.01). The results of this study suggest that left-sided hyperplastic colonic polyps (generally within the reach of a screening sigmoidoscopy) serve as a marker for neoplastic polyps.

Adolescent↗
PubMed1989

A marked guide wire facilitates esophageal dilatation.

Esophageal dilatation by endoscopists is a commonly performed procedure. The introduction of tapered polyvinyl dilators by Savary has made the procedure even more popular. In the United States, esophageal dilatation with guide wires has been traditionally performed with fluoroscopy. By using a marked guide wire and by adhering to specific safety guidelines, the passage of the guide wire can be precise, even without fluoroscopy, and radiographic definition is not always required. This study describes the new guide wire and the technique.

Dilatation↗
PubMed1988

Double-blind controlled trial of the Garren-Edwards gastric bubble: an adjunctive treatment for exogenous obesity.

Since its approval by the Food and Drug Administration in September 1985, the Garren-Edwards gastric bubble has been extensively used as an adjunct to diet and behavioral modification in the treatment of exogenous obesity. In an attempt to evaluate the efficacy of the Garren-Edwards gastric bubble, a double-blind crossover study was undertaken. Ninety patients were randomized into three groups: bubble-sham, sham-bubble, and bubble-bubble in two successive 12-wk periods. Sixty-one patients completed the entire 24-wk study. All groups participated in ongoing diet and behavioral modification therapy in a free-standing obesity program, the members of which were blinded to randomization arms. All patient groups lost weight during this study. The mean cumulative weight loss in pounds at 12 wk was as follows: bubble-sham = 19, sham-bubble = 12, and bubble-bubble = 8; and at 24 wk: bubble-sham = 23, sham-bubble = 16, and bubble-bubble = 18. The mean cumulative change in body mass index (kg/m2) at 12 wk was as follows: bubble-sham = -3.1, sham-bubble = -2.3, and bubble-bubble = -2.9; and at 24 wk: bubble-sham = -3.1, sham-bubble = -3.0, and bubble-bubble = -3.3. Although weight loss occurred more consistently in patients with a Garren-Edwards gastric bubble, there were no significant differences between any of the three groups at 12 or 24 wk with respect to weight loss or change in body mass index. The major part of the weight loss noted during this study occurred during the first 12-wk period, irrespective of therapy (bubble or sham). Side effects observed during this study included gastric erosions (26%), gastric ulcers (14%), small bowel obstruction (2%), Mallory-Weiss tears (11%), and esophageal laceration (1%). We conclude that, in this study, the use of a Garren-Edwards gastric bubble did not result in significantly more weight loss than diet and behavioral modification alone in the management of exogenous obesity, and it may result in significant morbidity.

Adolescent↗
PubMed1988

Gastric lipase: localization in the human stomach.

The aim of this study was to determine the range of activity and the location of lipase in the human stomach. The range of lipase activity in gastric mucosa of surgical specimens from the fundic area of 22 subjects was 594 to 3350 mU [mean, 1598 +/- 144 mU tri[3H]olein, (1 mU-1 nmol [3H]oleic acid released from tri[3H]olein per minute per milligram protein)]. For localization of activity, pinch biopsy specimens of gastric mucosa from 6 subjects were taken from the greater and lesser curvatures within 2 cm of the gastroesophageal junction (upper greater curvature and upper lesser curvature) and within 2 cm of the pylorus (lower greater curvature and lower lesser curvature). Lipase activity was higher in the upper greater curvature (405 +/- 92 mU) than in the upper lesser curvature (32 +/- 13 mU) and lowest in the antral area (16 +/- 9 mU in the lower lesser curvature and 10 +/- 2 mU in the lower greater curvature). The data show that in the human, lipase activity is localized primarily in the fundic area of the stomach. Comparison of the lipase activity levels in the gastric mucosa with lingual lipase activity levels in specimens of lingual serous glands indicates that in humans, gastric lipase is the main lipase active in the stomach.

Adult↗
PubMed1988

The effect of the Garren-Edwards Gastric Bubble on solid and liquid gastric emptying.

To determine the effect of the Garren-Edwards Gastric Bubble (GEGB) on gastric emptying, radionuclide solid and liquid gastric emptying in 12 obese patients prior to insertion of the GEGB was studied. Four were restudied at one and seven days and ten patients were restudied at twelve weeks with the GEGB in place. There were no significant differences in liquid gastric emptying at one and seven days nor in solid and liquid gastric emptying at twelve weeks. Solid gastric emptying was significantly decreased from a mean of 63% to 31% after one day (P less than 0.05) and returned to preplacement baseline by seven days. These results indicate that gastric emptying is not significantly changed after twelve weeks with the GEGB in place. Therefore, the mechanism of action for weight reduction with the GEGB is not likely to be mediated by an effect on gastric emptying. However, the solid food-induced dyspeptic symptoms commonly noted 1-3 days after placement of the GEGB, which resolve within seven days, are probably explained by transiently delayed solid gastric emptying.

Adolescent↗
PubMed1988

Basal gastric acid secretion in children with atypical epigastric pain.

We investigated basal acid output (BAO) by nasogastric aspiration in 28 children with atypical recurrent abdominal pain, defined as subxyphoid or epigastric pain of more than 3 months duration, associated with vomiting, anorexia, failure to thrive, and/or nocturnal awakening. Twenty-one children had normal upper endoscopies with no esophageal mucosal disease on biopsy, and seven had acid-peptic mucosal disease seen either on endoscopy or on esophageal biopsy. Mean BAO in the children with acid-peptic mucosal disease (6.8 +/- 4.3 mEq/h) was significantly higher than the mean BAO in the children with no mucosal disease (2.4 +/- 1.7 mEq/h) (p less than 0.02). Gastric volumes were also significantly greater in the children with acid-peptic mucosal disease than in children with no mucosal disease (p less than 0.001). There was no significant correlation between body weight and either BAO or basal volume output. Three of seven children with acid-peptic mucosal disease had a BAO greater than two standard deviations above the mean for the group with no mucosal disease. Two of these three had a BAO of more than 10.0 mEq/h (defined as gastric acid hypersecretion in adults), and required higher than usual doses of H2 blocker therapy. These results indicate that the values for BAO in children (greater than 2 yr) are comparable to values recorded in adults. Moreover, measurement of BAO may define a subgroup of children with atypical abdominal pain who are hypersecretors of acid and who require higher doses of antisecretory agents in order to achieve an optimal clinical response.

Abdomen↗
PubMed1987

Prospective study of the ability of computed axial tomography to localize gastrinomas in patients with Zollinger-Ellison syndrome.

The ability of routine computed tomography (CT) performed with oral and intravenous contrast to localize gastrinomas in 61 consecutive patients with Zollinger-Ellison syndrome was evaluated prospectively. The results of CT scanning were subsequently evaluated in all patients by either surgery, autopsy, or percutaneous biopsy. Thirteen of 14 patients with CT scans positive for hepatic metastases and 5 of 13 patients with CT scans negative for hepatic metastases were found to have gastrinoma in the liver. For gastrinoma metastatic to the liver, CT scanning had a specificity of 98%, a sensitivity of 72%, a positive predictive value of 93%, and a negative predictive value of 90%. Twenty-two of 23 patients with positive extrahepatic CT scans and 15 of 33 patients with negative extrahepatic CT scans were found to have extrahepatic gastrinomas. For extrahepatic gastrinoma, CT scanning had a specificity of 95%, a sensitivity of 59%, a positive predictive value of 96%, and a negative predictive value of 54%. The ability of CT scan to detect gastrinomas both in the liver and extrahepatically was directly related to tumor size, detecting 0% of tumors less than 1 cm and 83%-95% of tumors greater than 3 cm. The location of the extrahepatic gastrinoma was also an important determinant in that approximately 80% of pancreatic gastrinomas but only 35% of extrapancreatic gastrinomas were detected. The present results indicate that because of its convenience and accuracy, CT scanning with oral and intravenous contrast material should be the initial procedure to evaluate the extent of gastrinoma. A positive CT scan is almost always correct; therefore, a CT scan detecting metastatic gastrinoma to the liver would avoid unnecessary surgery and, if positive for extrahepatic gastrinoma, would assist the surgeon in finding the gastrinoma. A negative CT is less reliable; therefore, patients should undergo other localizing studies before exploratory laparotomy.

Biopsy↗
PubMed1987

Role of selective angiography in the management of patients with Zollinger-Ellison syndrome.

To determine the ability of selective abdominal angiography to localize gastrinoma in patients with Zollinger-Ellison syndrome, selective angiography was performed in 70 consecutive patients and the results were assessed prospectively by either surgery, autopsy, or percutaneous biopsy. In addition, to define the role of angiography in the management of patients with gastrinoma, we compared the results of angiography with those of computed tomography (CT) scanning in 58 patients who underwent both tests. For gastrinoma in the liver, angiography had a specificity of 100% and a sensitivity of 86% with a positive predictive value of 100% and a negative predictive value of 94%. For extrahepatic gastrinoma, angiography had a specificity of 94% and a sensitivity of 68%, a positive predictive value of 97% and a negative predictive value of 53%. Comparison of CT scanning and angiography demonstrated that for hepatic tumor CT demonstrated 72% and angiography 89% of tumors, and the combination detected all tumors with no false-positive results. Outside the liver, CT scanning detected 57%, angiography 70%, and the combination 73% of tumors with a false-positive rate of 7%. These results indicate that if a CT scan is performed first, then the addition of selective angiography will detect a further 28% of hepatic tumors and a further 16% of extrahepatic tumors, but that 24% of extrahepatic tumors will still be missed. Angiography is a useful adjunct to CT particularly in patients in whom surgery is contemplated.

Abdomen↗
PubMed1986

Prospective study of gastrinoma localization and resection in patients with Zollinger-Ellison syndrome.

In 1982, a prospective study was initiated of 52 consecutive patients with proven Zollinger-Ellison syndrome (ZES), involving surgical exploration with the goal of removing the gastrinoma after an extensive protocol to localize the tumor. Each patient underwent ultrasound, computed tomography (CT) with oral/intravenous (IV) contrast, and selective arteriography. Eighteen patients had metastatic disease identified by imaging studies and confirmed by percutaneous biopsies, and two patients had multiple endocrine neoplasia type I (MEN-I) with negative imaging studies; therefore, these 20 patients did not undergo laparotomy. Each of the remaining 32 patients (3 with MEN-I and positive imaging studies) underwent laparotomy, and gastrinomas were removed in 20 patients. Preoperative ultrasound localized tumors in 20% of patients, CT in 40%, arteriography in 60%, and any of the modalities in 70% of patients. Infusion CT and arteriography were 100% specific. In 18 patients with either negative imaging (17) or false-positive imaging (1 ultrasound), gastrinomas were found and removed in six patients (33%). Twenty-four gastrinomas were found in 20 patients at laparotomy: eight in lymph nodes around the pancreatic head, four in the pancreatic head, one in the pancreatic body, three in the pancreatic tail, three in the pyloric channel, one in the duodenal wall, two in the jejunum at the ligament of Treitz, one in the ovary, and multiple liver metastases in one patient. If one excludes patients with MEN-I or liver metastatic disease, 12/28 (43%) of patients were biochemically "cured" immediately after operation. This result decreased to 7/23 (30%) with greater than 6 months follow-up. No patients with gastrinomas resected have developed recurrent gastrinoma on follow-up imaging studies (longest follow-up: 4 years). This study indicates that 95% of metastatic gastrinoma can be diagnosed before operation and that, by a combination of careful imaging studies and thorough exploration at surgery, 30% of patients with gastrinomas may be curable.

Adult↗
PubMed1986

Selective venous sampling for gastrin to localize gastrinomas. A prospective assessment.

In 27 consecutive patients with Zollinger-Ellison syndrome, we prospectively evaluated the ability of selective venous sampling for gastrin to localize gastrinomas, then compared the results with those from imaging studies and with findings at surgery. All patients had a gastrin gradient, but in only 20 patients was it significant. Neither the magnitude of the gastrin gradient nor its presence or absence correlated with the frequency with which gastrinoma was found at surgery. A gastrinoma was found at surgery in 15 patients, of whom 12 had positive imaging studies, 11 had a significant gastrin gradient, 14 had both tests positive, and 1 had both tests negative. A gastrinoma was not found at surgery in 12 patients, of whom 8 had a significant gradient and none had a positive imaging study. Gastrin sampling has equal sensitivity with imaging studies in localizing gastrinoma, but imaging studies have higher positive and negative predictive values and higher specificity. Thus, selective venous sampling for gastrin is much less useful in localizing gastrinoma than has been suggested and should not be routinely done preoperatively in patients with Zollinger-Ellison syndrome.

Adult↗
PubMed1985

Omeprazole: effective, convenient therapy for Zollinger-Ellison syndrome.

The acute and long-term effects of omeprazole on gastric acid secretion were examined in 11 patients with Zollinger-Ellison syndrome. Basal gastric acid secretion was inhibited by 50% 3 h after a single 60-mg dose of omeprazole and 78% 4 h after administration of omeprazole. Patients were treated with a single daily dose of omeprazole, and the dose requirement was defined as the lowest dose of omeprazole that would reduce gastric acid secretion to less than 10 mEq/h during the last hour before the next dose. The mean daily dose requirement was 70 mg (range 20-160 mg). Ten of the 11 patients were given omeprazole once a day and 1 patient required omeprazole every 12 h. When omeprazole was discontinued after several months of therapy, mean basal gastric acid secretion was inhibited by greater than 50% 48 h after administration of omeprazole. Omeprazole continued to inhibit gastric acid secretion during 1-9 mo of therapy and patients remained free of toxicity or side effects related to omeprazole. Omeprazole is a highly effective inhibitor of gastric acid secretion in patients with Zollinger-Ellison syndrome. Because of its potency and long duration of action, omeprazole offers an advance in convenient medical therapy for Zollinger-Ellison syndrome compared with the histamine H2-receptor antagonists.

Adult↗
PubMed1985

Famotidine, a new, potent, long-acting histamine H2-receptor antagonist: comparison with cimetidine and ranitidine in the treatment of Zollinger-Ellison syndrome.

Famotidine, a new, potent, long-acting histamine H2-receptor antagonist was compared with cimetidine and ranitidine in 9 patients with Zollinger-Ellison syndrome. The mean minimum daily requirement of famotidine to control gastric acid hypersecretion was 0.24 g (range 0.08-0.48 g) compared with 2.1 g (range 0.6-3.6 g) for ranitidine and 7.8 g (range 1.2-13.2 g) for cimetidine. Equally potent doses of the three drugs had similar onsets of action, but the duration of action of famotidine was 30% longer than the duration of action of either ranitidine or cimetidine (p less than 0.05). Eight patients were treated for up to 9 mo (mean 6 mo) with good control of gastric acid hypersecretion and with no evidence of biochemical or hematologic toxicity. These studies demonstrate that famotidine is nine times more potent than ranitidine and 32 times more potent than cimetidine, has a longer duration of action than ranitidine or cimetidine, and is both safe and effective in the long-term therapy of Zollinger-Ellison syndrome.

Aged↗
PubMed1984

Comparison of the effectiveness of ranitidine and cimetidine in inhibiting acid secretion in patients with gastric hypersecretory states.

The H2-histamine receptor antagonists ranitidine and cimetidine were compared for their abilities to control gastric acid hypersecretion on a short- and long-term basis in 22 patients with gastric acid hypersecretory states. Nineteen patients had Zollinger-Ellison syndrome, one patient had systemic mastocytosis, and two patients had idiopathic hypersecretion. The rates of onset of the action of cimetidine and ranitidine were the same. The actions of both drugs were increased by anticholinergic agents, and there was a close correlation between the daily maintenance dose of each drug needed to control acid secretion. However, ranitidine was threefold more potent than cimetidine both in acute inhibition studies and in the median maintenance dose needed (1.2 g per day for ranitidine and 3.6 g per day for cimetidine). Sixty percent of the males developed breast changes or impotence while taking cimetidine and in all cases these changes disappeared when cimetidine was replaced by ranitidine. Treatment with high doses of cimetidine (one to 60 months; median, 11 months) or ranitidine (two to 31 months; median, 14 months) was not associated with hepatic or hematologic toxicity or alterations of serum gastrin concentrations, but ranitidine therapy was associated with a significantly lower serum creatinine level than seen with cimetidine therapy. The results show that both drugs can adequately inhibit acid secretion in patients with gastric hypersecretory states. Both are safe at high doses, but ranitidine is threefold more potent and does not cause the antiandrogen side effects frequently seen with high doses of cimetidine.

Adult↗
PubMed1984

Receptors for vasoactive intestinal peptide and secretin on rat pancreatic acini.

In dispersed acini from rat pancreas, binding of 125I-labeled vasoactive intestinal peptide and 125I-labeled secretin was relatively rapid, reversible, saturable, and temperature dependent. The rate of dissociation of bound 125I-labeled peptide was not a function of the concentration of free vasoactive intestinal peptide or secretin, indicating that the apparent affinities of these labeled peptides for their binding sites do not depend on the extent of receptor occupation. Four classes of receptors are required to account for the actions of vasoactive intestinal peptide and secretin on enzyme secretion, cellular cAMP, and binding of 125I-vasoactive intestinal peptide and 125I-secretin. One class has a high affinity for vasoactive intestinal peptide, and occupation of this class of receptors causes increased cellular cAMP and stimulation of amylase secretion. A second class has a low affinity for vasoactive intestinal peptide and for secretin, and occupation of these receptors does not cause changes in cAMP or amylase secretion. A third class of receptors has a high affinity for secretin, and occupation of these receptors causes increased cAMP and stimulation of amylase secretion. A fourth class of receptors has a low affinity for secretin, and occupation of these receptors causes stimulation of amylase secretion by a non-cAMP-mediated mechanism.

Amylases↗
PubMed1984

Localization of islet cell tumors by dynamic CT: comparison with plain CT, arteriography, sonography, and venous sampling.

Ten patients with suspected islet cell tumors (seven with possible gastrinomas, three with insulinomas) underwent diagnostic evaluation with dynamic CT scanning, routine CT scanning, angiography, and sonography. Venous sampling was also performed in selected instances. Nine sites of gastrinoma and three insulinomas were confirmed surgically in eight patients. Two patients had negative surgical explorations. Routine CT demonstrated five of the nine gastrinomas and one of two insulinomas. Angiography was positive in six of nine gastrinomas and all three insulinomas. Sonography showed only two of the nine gastrinomas and two of the three insulinomas. Dynamic CT scanning demonstrated three additional lesions (two gastrinomas, one insulinoma) not visible on routine CT scanning. Although most of these lesions were visible arteriographically, dynamic CT scans at the appropriate level localized the pathology in the transverse plane and greatly aided in surgical resection of these lesions. Dynamic CT scanning is a useful adjunct to routine angiographic and CT workup of patients with islet cell tumors.

Adenoma, Islet Cell↗