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S B Benjamin

Publications and source records attributed to S B Benjamin.

At least 37 records · Page 2Linked to original sources
PubMed1995

Dietary fat modulates gastric lipase activity in healthy humans.

The aim of this study was to determine whether the amount of dietary fat modulates the activity of gastric lipase in humans. Gastric juice was collected from six healthy subjects after 2-wk periods of either a high-fat (50% of energy as fat) or low-fat (25% of energy as fat) diet. The collection period lasted 2 h, the first hour under baseline conditions and the second hour after pentagastrin stimulation (6 micrograms/kg body wt). Gastric lipase and pepsin activities were quantitated at 15-min intervals and total enzyme outputs were calculated. Under baseline conditions there was a tendency for higher output of gastric lipase and pepsin after the high-fat diet than after the low-fat diet (gastric lipase: 745 compared with 446 U/h, pepsin: 107,677 compared with 78,505 U/h). The difference in output between diet groups was significant after pentagastrin stimulation (gastric lipase: 1323 compared with 875 U/h, pepsin: 191,751 compared with 128,961 U/h, for high-fat compared with low-fat diet, respectively, P < 0.05). This study is the first to report that a high-fat diet leads to an increase in the activity of gastric enzymes in humans.

Adaptation, Physiological↗
PubMed1995

Esophageal function and occurrence of Barrett's esophagus in Zollinger-Ellison syndrome.

Manifestations of esophageal disease are present in up to 60% of patients with Zollinger-Ellison syndrome (ZES), although esophageal function has been studied in only a few patients and the prevalence of Barrett's mucosa is unknown in these patients. It is unclear whether the high prevalence of esophageal disease is related to gastric acid hypersecretion alone or to abnormalities of esophageal motility or lower esophageal sphincter (LES) function in addition. To address these issues in the present study esophageal function was evaluated prospectively in 92 consecutive patients with ZES (66 with active disease, 26 disease-free after curative resection) seen during a 1-year period after controlling acid hypersecretion. In the patients with active disease the mean basal acid output (BAO) was 33 +/- 3.0 mEq/h, the maximal acid output (MAO) was 56 +/- 4.0 mEg/h, fasting serum gastrin was 8,736 +/- 4,813 pg/ml and duration of disease prior to study was 12.5 +/- 2.0 years. At the time of manometry, gastric acid secretion was controlled in all patients and no patient had evidence of gastroesophageal reflux disease at upper gastrointestinal endoscopy. Esophageal manometry revealed normal motility in 85% of patients. Eleven percent had low LES pressures, and only 1% of patients had an elevated LES pressure. The frequency of Barrett's mucosa (3%) was similar to that found in the general population but much less than that reported in patients with idiopathic GERD. No correlation was noted between LES pressures or manometric abnormalities and the fasting serum gastrin, BAO, MAO or the presence or absence of multiple endocrine neoplasia type I or previous vagotomy. Esophageal manometric results and LES pressure were similar in disease-free patients and those with active ZES. In conclusion, these results suggest that hypergastrinemia or other disease-specific abnormalities are not contributing to the high incidence of esophageal disease in patients with ZES because esophageal function in patients with ZES is similar to normals. Specifically, motility disorders in patients with ZES occur in similar frequency to normals, and LES pressure is normal in most patients. Despite the high levels of acid secretion and prominence of symptoms, the occurrence of Barrett's mucosa was uncommon (3%) raising the possibility of additional protective mechanisms in patients with ZES.

Adult↗
PubMed1992

Microvascular angina and the sensitive heart: historical perspective.

As our understanding of the etiology of chest pain of undetermined origin has evolved, the focus for studying this problem has switched from individual subspecialties to a multidisciplinary approach. In the subspecialties of gastroenterology and cardiology, the focus has shifted from organ-specific diagnoses to concepts of altered pain thresholds. Cardiologists began to look for functional causes of ischemia following the recognition that many patients with chest pain had normal coronary arteries. Abnormal responses of the coronary microcirculation to stress were identified in this population, and the concept of "microvascular angina" originated. Further evaluation, however, demonstrated that many of these patients did not have evidence of ischemia. In addition, a significant overlap with esophageal motility disorders was shown, and multiple sensitivities to otherwise nonirritating stimuli, whether in the heart or the esophagus, could be elicited in these patients. This finding led to the concept of abnormal visceral nociception, that is, the "sensitive heart" and the "tender esophagus," both the focus of ongoing clinical research.

Angina Pectoris↗
PubMed1992

Intraoperative bile duct sonography during laparoscopic cholecystectomy: experience with a 12.5-MHz catheter-based US probe.

During elective laparoscopic cholecystectomy, 20 patients underwent intraoperative evaluation of the biliary tract with a commercial 6.2-F, 12.5-MHz catheter-based ultrasound (US) probe. The study tested the feasibility of this technology for mapping the anatomy of the hepatoduodenal ligament and Calot triangle, assessing bile duct integrity, and detecting choledocholithiasis. The duct was studied with a transmural approach, the catheter being placed parallel to, but remaining outside, the bile duct. The common hepatic duct and common bile duct in the vicinity of the cystic duct were seen in all 20 patients; the junction of the cystic duct with the common hepatic duct was seen in nine patients (45%). After the cystic duct was clamped, no sonographic evidence to suggest bile duct injury was noted in any patient. The transmural imaging approach was tested in four pigs in whose common bile duct a single human calculus had been placed. In all instances the size and location of the calculus were accurately detected. Intraoperative US with a catheter-based system is a safe and effective means for interrogation of the extrahepatic biliary tree during laparoscopic cholecystectomy.

Adult↗
PubMed1991

Islet cell carcinoma of the pancreas presenting as bleeding from isolated gastric varices. Report of a case and review of the literature.

Gastrointestinal hemorrhage from left-sided portal hypertension and gastric varices is an unusual presentation for islet cell carcinoma of the pancreas. Islet cell tumors of the pancreas themselves are rare. They present in a variety of ways. Those that elaborate functional hormones cause specific neuroendocrine syndromes. Nonfunctional tumors characteristically present later with symptoms of metastatic disease or as a result of local enlargement. We present a case of islet cell carcinoma of the pancreas presenting with recurrent gastrointestinal bleeding from gastric varices and review the literature for this rare presentation. We emphasize the importance of a careful initial diagnostic work-up that may enable curative surgery.

Adenoma, Islet Cell↗
PubMed1991

Lipase and pepsin activity in the gastric mucosa of infants, children, and adults.

The range of activity and the location of lipase and pepsin were determined in the stomach and duodenum of infants, children, and adults. The range of lipase activity in biopsy specimens from the gastric body, in 29 subjects aged from 3 months to 26 years, was 1.8-5.3 U/mg protein (1 U is 1 mumol [3H]oleic acid released from tri-[3H]olein per minute). There were no significant differences among age groups (5-19 months, 2-4 years, 6-10 years, 11-13 years, and 15-26 years). Lipase activity was low or undetectable in the gastric antrum of all subjects. Pepsin activity in specimens from the gastric body ranged from 180 to 780 pepsin units/mg protein (using hemoglobin as substrate). The antrum had significantly lower pepsin activity (P less than 0.001) than the gastric body. As with lipase activity, there were no statistically significant differences in pepsin activity among age groups. Lipase and pepsin activity was also quantified in pinch biopsy specimens from the duodenum and duodenal bulb in 13 subjects. Contrary to lipase activity, which was almost completely absent from the duodenum or duodenal bulb, these sites contained low pepsin activity (9-78 pepsin units/mg protein). The data show that in infants and children, as previously reported in adults, gastric lipase is localized primarily in the gastric body. Tissue pepsin levels and localization, reported here for the first time, are similar to those of lipase, although, contrary to lipase, the gastric antrum has considerable pepsin activity. The identical levels of lipase and pepsin activities in infants, children, and adults indicate that the gastric phase of nutrient digestion is well developed at birth.

Adolescent↗
PubMed1990

Coronary flow reserve, esophageal motility, and chest pain in patients with angiographically normal coronary arteries.

PURPOSE AND METHODS: To ascertain the relative prevalence of abnormalities of coronary flow reserve and esophageal function in patients with chest pain despite angiographically normal coronary arteries, 87 patients underwent invasive study of coronary flow reserve and, during the same week, esophageal testing. RESULTS: Sixty-three of the 87 patients (72%) demonstrated abnormalities of coronary flow reserve, as evidenced by an increase in coronary resistance during the stress of rapid atrial pacing after administration of ergonovine 0.15 mg intravenously (1.33 +/- 0.36 mm Hg.minute/mL), compared with pacing at the same heart rate before ergonovine administration (1.10 +/- 0.33 mm Hg.minute/mL). This higher coronary vascular resistance occurred in the absence of significant epicardial coronary artery luminal narrowing. Fifty-seven of these 63 patients (90%) with a coronary vasoconstrictor response to ergonovine described their typical chest pain during pacing stress, compared with only six of 24 patients (25%) who demonstrated no coronary flow abnormality (p less than 0.001). After administration of dipyridamole 0.5 to 0.75 mg/kg intravenously to 65 patients, the 48 patients with ergonovine-induced vasoconstriction had a significantly higher minimum coronary resistance, compared with the 17 patients without a coronary vasoconstrictor response to ergonovine (0.65 +/- 0.21 versus 0.47 +/- 0.13 mm Hg.minute/mL, p less than 0.03). Twenty of 87 patients (23%) had abnormal esophageal motility [nutcracker esophagus (11), nonspecific motility disorder (seven), and diffuse esophageal spasm (two)], including 16 of the 63 patients (25%) with abnormal coronary flow reserve. Twenty-four (28%) patients experienced their typical chest pain during motility testing, but only five of these patients met criteria for abnormal esophageal motility. Nine of 75 patients tested (12%) had their typical chest pain during Bernstein testing, and 18 of 38 patients (47%) tested had their typical chest pain provoked by intraesophageal balloon distention. CONCLUSIONS: Seventy-one of 87 patients (82%) with anginal-like chest pain and normal epicardial vessels in our series had a disorder of either coronary flow reserve, esophageal motility, and/or reproduction of typical chest pain during acid infusion. Of interest, chest pain was commonly encountered during cardiac and esophageal testing (85% of patients), regardless of the ability to demonstrate an abnormality of coronary flow reserve or abnormal esophageal function. This suggests that pain experienced by these patients may be a consequence of myocardial ischemia, esophageal dysfunction, abnormal visceral nociception, or a combination of any or all of these entities.

Adult↗
PubMed1990

Gastric acid hypersecretion in refractory gastroesophageal reflux disease.

We prospectively evaluated gastric acid output (mEq/h), gastric volume output (ml/h), ambulatory 24-h esophageal pH monitoring, and the endoscopic appearance of the esophagus in 23 patients undergoing treatment of chronic long-standing pyrosis. Twelve of these 23 individuals (52%) remained symptomatic after 3 mo of standard antisecretory treatment with ranitidine, 150 mg twice daily. When compared with initial responders, those patients who did not experience complete symptomatic relief on therapy had significantly higher basal acid output (p less than 0.001), basal volume output (p less than 0.02), and basal upright (but not supine) reflux time (p less than 0.05). Nine of the 12 patients who did not respond to initial treatment had gastric acid hypersecretion (basal acid output greater than 10 mEq/h), and 10 of the 12 had Barrett's epithelium compared with only 1 patient in the initial-responder group (p less than 0.001). All 12 nonresponders were treated for an additional 3 mo with increased doses of ranitidine (mean, 1280 mg/day; range, 600-1800 mg/day), and complete disappearance of pyrosis occurred in 10 of the 12, although no significant endoscopic regression was observed in the extent of the underlying columnar mucosa in those with Barrett's esophagus over the 6-mo duration of the study. A significant correlation was shown between the daily ranitidine dose required to eliminate symptoms and the pretreatment basal acid output (r = 0.81, p less than 0.001); gastric acid output had to be almost totally suppressed (i.e., less than 1 mEq/h) for pyrosis to disappear completely. No side effects occurred with any of these high doses of ranitidine. We conclude that a subgroup of patients with long-standing symptomatic gastroesophageal reflux disease who do not respond to standard ulcer-healing doses of histamine2-receptor antagonists are hypersecretors of basal gastric acid and require increased acid-suppressive therapy. Many of these individuals also have underlying Barrett's epithelium.

Adolescent↗
PubMed1990

Histopathologic analysis of suspected amiodarone hepatotoxicity.

This analysis of the morphology of suspected amiodarone (AD) liver disease is based on a study of liver specimens from 17 individuals. Changes similar to alcoholic liver injury were commonly seen. Steatosis, both macrovesicular and microvesicular, was the most frequent histopathologic feature. Ballooning of hepatocytes, Mallory bodies, and fibrosis were also common. Other changes included nuclear unrest, acidophilic bodies, foam cells, glycogenated nuclei, and portal inflammation. Characteristic lamellar lysosomal inclusion bodies representing phospholipidosis were found in two of 14 specimens studied ultrastructurally. These changes of pseudoalcoholic hepatitis and/or phospholipidosis were present in liver specimens from asymptomatic, anicteric patients with mild elevations in serum aminotransferase or alkaline phosphatase values with or without hepatomegaly, as well as in patients with clinically overt symptoms of hepatotoxicity. Phospholipidosis appears to be a generalized systemic effect of cationic amphophilic compounds, such as AD. The cytotoxic pseudoalcoholic changes appear to be an independent phenomenon in susceptible patients, whom we speculate may have been unable or less able to metabolize AD through normal pathways. The true incidence of hepatic injury from AD remains to be determined from prospective evaluations of pretreatment and follow-up liver biopsies.

Adolescent↗
PubMed1990

Solid and papillary epithelial neoplasm of the pancreas: clinical findings of a rare tumor.

A young woman presented with a large pancreatic mass that was found to be a solid and papillary epithelial neoplasm. The endoscopic, radiologic, and gross appearance of this tumor is described. The origin of the tumor is probably from a multipotential stem cell of the pancreas. Surgical resection is usually curative, although radiotherapy and chemotherapy have been successfully used. This unusual tumor should be considered in the differential diagnosis of a young female with a pancreatic mass.

Adult↗
PubMed1990

Overview of monitoring in endoscopy.

Gastrointestinal endoscopy has evolved rapidly over the past 30 years and has become one of the larger specialities in medicine. An increasing number of diagnostic and therapeutic procedures are being performed with the aid of the flexible endoscope. With this expansion in the use of endoscopy came the routine administration of premedication. The endoscopist thus became a part-time anaesthetist. The lack of proper studies to evaluate the untoward effects of diazepam and, later, midazolam, at their introduction led to an unfortunate increase in reports of fatalities after the introduction of midazolam. Later studies showed the safety of these agents when properly administered, but the affair served to focus attention on monitoring in gastrointestinal endoscopy. The benefits of using extracorporeal monitoring equipment during endoscopy has not been proved in clinical trials, and because of this those bodies that issue guidelines on medical practice, such as the American Society for Gastrointestinal Endoscopy, have not mandated the use of these devices. The guidelines issued have emphasized the importance of training and recertification in advanced cardiac life support. Many endoscopists are reluctant to recognize their role as anaesthetist, and to adopt new practices recommended in the guidelines. However, these changes represent the evolution of medicine and reflect the desire to ensure a uniform high quality of care and as such should not be resisted.

Anesthesia↗
PubMed1990

Intraesophageal balloon distention versus drug provocation in the evaluation of noncardiac chest pain.

Intraesophageal balloon distention (IEBD) has been advocated as an effective provocative test for the evaluation of chest pain and dysphagia. The normal esophageal response to intraesophageal balloon distention is to generate a sustained contraction proximal to the balloon while showing a distinctive absence of activity distal to the balloon. We evaluated intraesophageal balloon distention in 62 patients with noncardiac chest pain and compared the diagnostic results to those obtained by using a combination of acid infusion, edrophonium (80 micrograms/kg iv) and bethanechol (80 micrograms/kg sq). These 62 patients were also compared with 10 normal volunteers who underwent intraesophageal balloon distention. Abnormal distal manometric activity consistent with spasm and was seen in 38/62 (61%) patients. Distal manometric activity was not seen in any normal volunteer. Diagnostic results (symptom reproduction with manometric changes but without EKG changes) were seen in 26/62 (42%) patients, but in nine of the 62 (14%) patients with combined drug provocation (p less than 0.05). Intraesophageal balloon distention is superior to a combination of provocative drugs in evaluating noncardiac chest pain symptoms. The presence of abnormal manometric activity distal to the balloon may represent regulation of esophageal motility.

Bethanechol↗