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Biomedical subjects

F E Silverstein

Publications and source records attributed to F E Silverstein.

At least 19 recordsLinked to original sources
PubMed1995

Misoprostol reduces serious gastrointestinal complications in patients with rheumatoid arthritis receiving nonsteroidal anti-inflammatory drugs. A randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To investigate whether concurrent administration of misoprostol reduces the occurrence of serious upper gastrointestinal complications, such as perforation, gastric outlet obstruction, or bleeding, in patients with rheumatoid arthritis who are receiving nonsteroidal anti-inflammatory drugs (NSAIDs). DESIGN: 6-month randomized, double-blind, placebo-controlled trial. SETTING: 664 clinical practices of family medicine, internal medicine, or rheumatology in the United States and Canada. PATIENTS: 8843 men and women (mean age, 68 years) receiving continuous therapy with any of 10 specified NSAIDs for control of symptoms of rheumatoid arthritis. Patients were enrolled between July 1991 and August 1993. INTERVENTION: Patients were randomly assigned to receive 200 micrograms of misoprostol or placebo four times a day. MEASUREMENTS: Development of serious upper gastrointestinal complications detected by clinical symptoms or findings (not by scheduled endoscopy). RESULTS: Serious upper gastrointestinal complications were reduced by 40% (odds ratio, 0.598 [95% CI, 0.364 to 0.982; P = 0.049]) among patients receiving misoprostol (25 of 4404 patients) compared with those receiving placebo (42 of 4439 patients). During the first month, more patients receiving misoprostol (20%) than placebo (15%) withdrew from the study, primarily because of diarrhea and related problems (P < 0.001). Risk factors for serious upper gastrointestinal complications were increasing age, history of peptic ulcer or bleeding, and cardiovascular disease. Patients with all four risk factors would have a 9% risk for a major complication in 6 months. CONCLUSIONS: In older patients with rheumatoid arthritis, misoprostol reduced serious NSAID-induced upper gastrointestinal complications by 40% compared with placebo.

Aged↗
PubMed1995

Future developments in endoscopic imaging.

Endoscopic imaging capabilities have significantly improved over the past 10 years. Improvements in fibreoptic technology have made possible the development of very thin endoscopes that can directly visualize the biliary and pancreatic ducts. The application of the CCD to endoscopy has made electronic endoscopy possible, and holds promise for stereoendoscopy. The ability to digitize endoscopic images can be developed to store, transmit, magnify, enhance and otherwise manipulate data obtained during endoscopy, and will probably be utilized routinely in the future. Laser and ultrasound technology are likely to enhance significantly our ability to examine ultrastructural aspects of gastrointestinal organs and surrounding tissues, and may play an important role in cancer surveillance programs. Vital staining techniques are likely to find widespread use in early cancer detection programmes, and may be useful to follow prospectively lesions observed or treated during endoscopy. Finally, the new developments in 'virtual imaging' may find applications in the field of gastrointestinal endoscopy and other 'minimally invasive' surgical procedures.

Diagnostic Imaging↗
PubMed1995

Simultaneous M-mode echoesophagram and manometry in the sheep esophagus.

We report the simultaneous measurement of esophageal wall layer thickness and intraluminal pressure in the sheep esophagus using a miniature suction device incorporating a high-frequency ultrasound transducer and a manometry system. Transnasal placement of the device into the distal esophagus of a conscious sheep allowed observation of 133 swallowing events during three trials, each lasting from 45 to 60 minutes. In a fourth trial, 11 sequential dry and 23 sequential wet swallows were compared. Maximum manometric pressure, esophageal wall layer thickness, and duration of contraction were measured. All swallowing events produced simultaneous increases in intraluminal pressure and esophageal wall thickness. Mean maximal pressures were lower for dry swallows (18 +/- 2.1 mm Hg) than wet swallows (22 +/- 3.0 mm Hg) (p < .01). Thickness of the inner (circular) muscle layer increased above baseline by 124% for dry swallows and 161% for wet swallows (p < .01). We conclude that thickening of the esophageal inner (circular) muscle layer may be important in the generation of intraluminal esophageal pressure in the sheep esophagus.

Animals↗
PubMed1994

Chemical- and radiation-induced esophageal injury.

The esophageal wall can only respond to injury in a limited fashion. This article explores some of the protective mechanisms involved as well as current approaches to diagnosis and management of chemical- and radiation-induced esophageal injury.

Burns, Chemical↗
PubMed1992

Use of ultrasound to detect intestinal wall ischemia in piglets.

To evaluate the use of ultrasound (US) to detect intestinal wall ischemia, we isolated segments of jejunum on single vascular pedicles in five piglets. We sequentially clamped these segments in intervals of 0 to 6 h, reperfused them for 24 h, and then examined them in vitro histologically and with an 8.5 MHz US scan. All segments were grossly viable except those with 6 h of ischemia. Histologically, mild submucosal edema developed after 1 to 2 h of ischemia; after 3 to 4 h, mucosal necrosis, loss of folds, worsening submucosal edema, and prominent neutrophilic infiltration occurred; after 5 to 6 h, severe mucosal necrosis with hemorrhage and submucosal edema was present. Ultrasonically, we saw five wall layers in the control group corresponding to mucosa, submucosa, muscularis propria, and subserosal fat. After mild (1 to 2 h) ischemia, all layers were present except for a discontinuity in layer 3. After moderate (3 to 4 h) ischemia, the five layers persisted but with a markedly thickened submucosal layer, reduced echogenicity, and flattened mucosal folds. With severe (5 to 6 h) ischemia, we observed a loss of all normal layers with no discernible architecture. Using these US criteria, blinded observers were able to differentiate normal/mild from moderate/severe ischemia with a sensitivity and specificity of 100%. These data suggest that US can differentiate, in vitro, normal from moderate and severe degrees of intestinal wall ischemia that correlates well with the histological appearance. Endoscopic US or surgically implantable US probes can potentially help diagnose clinical intestinal wall ischemia.

Animals↗
PubMed1992

Clinical application of linear ultrasound probes.

The linear ultrasound probe should be viewed as an adjunct to conventional endoscopic ultrasonography with combined ultrasound endoscopes. It certainly does not replace these instruments for staging neoplasms and imaging extraintestinal organs such as the pancreas. It can be a simpler alternative to these instruments when applied at the time of endoscopy to obtain more information about wall thickness and the cause of an intramural mass. It can add information when used to image within impassable malignant strictures. Further development of the linear probes with the addition of a balloon over the transducer and the advent of new probes that utilize other scanning mechanisms is anticipated and should make this imaging system even more useful.

Endoscopy↗
PubMed1992

Evaluation of a 20-MHz ultrasound transducer used in diagnosing porcine small bowl ischemia.

The authors have previously demonstrated the ability of an 8.5-MHz linear array to detect moderate or severe intestinal ischemia in a porcine model. This study compares the ability of the 8.5-MHz linear array with a prototype miniature 20-MHz ultrasound (US) imaging probe in detecting small bowel ischemia. Five piglets were studied in which vascular clamps were applied to isolated jejunal pedicles, then released sequentially at hourly intervals to induce ischemia from 0 to 6 hours. After 24 hours of reperfusion, the tissue was removed and examined with both the 8.5-MHz linear array and the 20-MHz probe. A histologic examination also was done. The acoustical criteria used for interpretation were presence or absence of folds, number of echo layers, relative thickness of layers and homogeneity and continuity of layers. The 8.5-MHz system predicted the duration of ischemia with a kappa value of 0.66 +/- 0.03, whereas the 20-MHz system had a kappa value of 0.49 +/- 0.03. Both systems were able to distinguish normal or mild ischemia from moderate or severe ischemia with sensitivity and specificity rates of at least 94%. Both 8.5- and 20-MHz US systems detected intestinal ischemia in vitro. Further studies are indicated to determine the ideal frequency and design for a US system that can be used clinically.

Animals↗
PubMed1990

Diagnosis of inflammatory bowel disease with ultrasound. An in vitro study.

Transabdominal ultrasound is frequently used to detect complications of inflammatory bowel disease. It has been proposed that ultrasound can distinguish between ulcerative colitis and Crohn's disease based on the degree of thickening and changes in the layered structure of the intestine. The authors evaluated the ability of ultrasound to distinguish between ulcerative colitis, Crohn's colitis, and normal colon by blindly comparing images made of resected colon specimens. The histologic interpretation of precisely the same area of tissue that was imaged was compared with the blinded image interpretation. Images from all 18 colitis specimens were correctly interpreted as being abnormal because of increased submucosal and overall wall thickness. Published ultrasound criteria for distinguishing between Crohn's disease and ulcerative colitis based on overall wall thickness and indistinctness of layers were inaccurate in 4 of 15 specimens and indeterminate in 3 cases. Ultrasound appears to be accurate in distinguishing normal from inflamed colon, but ultrasound findings alone should not be used to determine the cause of bowel inflammation.

Colitis, Ulcerative↗
PubMed1989

Histologic correlates of gastrointestinal ultrasound images.

Endoscopic ultrasound imaging has potential for improving the diagnosis of gastrointestinal disease. However, the anatomic correlates of gastrointestinal ultrasound images have not been precisely defined. We have compared ultrasound images with the corresponding histologic sections of 81 specimens of resected and postmortem, normal and diseased gastrointestinal tissue. The five layers seen on ultrasound images of the normal gastrointestinal tract correspond to (1) superficial mucosa, (2) deep mucosa, (3) submucosa plus the acoustical interface between the submucosa and muscularis propria, (4) muscularis propria minus the acoustical interface between the submucosa and muscularis propria, and (5) serosa and subserosal fat. This interpretation takes into consideration the echoes produced by the tissue layers and the echoes produced by the interfaces between layers. Abnormal findings on ultrasound images of neoplastic and inflammatory diseases correspond to histologic tissue structure. When properly interpreted, ultrasound images of the gastrointestinal wall can provide potentially useful diagnostic information.

Digestive System↗
PubMed1989

Experimental evaluation of an endoscopic ultrasound probe: in vitro and in vivo canine studies.

We developed an endoscopic echo probe that can be passed via the biopsy channel of a flexible fiberoptic or video endoscope with a 3.5-mm channel. The probe moves along the gastrointestinal wall under direct endoscopic vision. The translational scanning action is sensed by a position potentiometer and combines with the ultrasonic B-mode echoes to produce a cross-sectional image of the wall. The system uses an ultrasound frequency of 20 MHz to produce high-resolution images. The device was used to image canine gastrointestinal tissue in vitro and in vivo during endoscopy. Ultrasound images of the gut wall correlate with histologic structure. This probe overcomes some of the problems associated with the combined ultrasound endoscopes now in use. Use of the probe with video endoscopy allows the endoscopic and ultrasound images to be displayed side by side, simplifying coordination of application of the two techniques.

Animals↗
PubMed1989

A 20-MHz ultrasound system for imaging the intestinal wall.

An ultrasound system has been developed which uses high-frequency (20 MHz) ultrasound to provide high-resolution images of tissue. The system provides 0.21-mm range and 0.65-mm lateral resolution. The transducer aperture size is 1.8 mm maximum. Miniature probes have been developed which can image via the biopsy channels of standard fiberoptic endoscopes as well as probes for imaging in vitro. A commercially available video "frame grabber" is used in conjunction with a standard microcomputer for image acquisition. This allows images to be displayed and recorded on standard television equipment and be stored and manipulated digitally. The features of the system allow in vivo imaging, in vitro imaging after resection, and histological images of the same tissue region to be acquired and compared. This method is particularly useful in learning how to correctly interpret ultrasonic images of the intestinal wall. The use of 20 MHz is advantageous in achieving excellent resolution and small size probes. The system provides a unique approach to imaging the intestinal wall.

Analog-Digital Conversion↗
PubMed1989

Misoprostol reduces gastroduodenal injury from one week of aspirin: an endoscopic study.

Misoprostol is a synthetic prostaglandin E1 analogue that inhibits gastric acid production and may augment mucosal defense. A double-blind trial examined the effect of misoprostol on the endoscopic appearance of gastroduodenum at the end of 1 wk of aspirin ingestion. One hundred thirty healthy subjects were randomized to take either 50, 100, or 200 micrograms of misoprostol, or placebo along with 975 mg of aspirin four times daily. Fewer subjects developed acute endoscopic gastric ulcers in the group taking any dose of misoprostol compared with the placebo group (1% vs. 43%). No subject taking the 100- or 200-micrograms dose of misoprostol developed an acute endoscopic duodenal ulcer compared with 13% of subjects taking placebo (p less than 0.05). Significantly fewer subjects developed gastric erosions and significantly fewer subjects developed duodenal erosions in each of the three groups taking misoprostol compared with the placebo group (p less than 0.01). There were fewer subjects with a gastric erosion (p less than 0.05) and fewer subjects with a duodenal erosion (p less than 0.05) in the group taking the 200-micrograms dose compared with the group taking the 50-micrograms dose of misoprostol. Gastrointestinal symptoms causing a modification in usual activities were infrequent but there was significantly more diarrhea in the 200-micrograms misoprostol group. There was no correlation between endoscopic scores and symptoms in any group. We conclude that misoprostol can protect the normal gastroduodenum from acute ulceration and reduce the chance of erosion after 1 wk of aspirin ingestion.

Adolescent↗
PubMed1988

Role of H2-receptor blockers in the prevention of gastric injury resulting from nonsteroidal anti-inflammatory agents.

Nonsteroidal anti-inflammatory drugs (NSAIDs) can produce injury to the gastric and duodenal mucosa. The histamine (H2)-receptor blocker cimetidine was studied to determine whether protection of the gastric mucosa of normal volunteers could be provided against a single dose of aspirin, 1,300 mg. Gastric mucosal injury was assessed with gastroscopy performed two hours after aspirin intake. Three liquid cimetidine doses were administered over 24 hours prior to the aspirin dose, the last dose one hour before the aspirin. The 200-mg and 400-mg doses of cimetidine protected a sufficient number of subjects to warrant further study. In the second study, these two doses were further examined to determine whether three doses were necessary and whether the final dose could be coadministered with the aspirin instead of one hour before. Concomitant administration of a single dose of cimetidine with aspirin was found to protect the gastric mucosa from aspirin damage as effectively as the other cimetidine regimens employed. A final, double-blind comparison of cimetidine, 200 mg, with placebo administered with the aspirin, 1,300 mg, confirmed that cimetidine protected the gastric mucosa from the hemorrhagic effects of aspirin.

Aspirin↗
PubMed1987

Gastric protection by misoprostol against 1,300 mg of aspirin. An endoscopic dose-response study.

Misoprostol at a dose of 200 micrograms inhibits gastric acid secretion and protects the gastric mucosa against the injurious effects of a single 1,300-mg dose of aspirin. The purpose of this study was to determine whether lower subantisecretory doses of misoprostol protect the gastric mucosa in this single-dose aspirin model. Protection was defined as no more than 10 hemorrhagic spots and no more than two hemorrhagic streaks. A total of 140 men participated in the two phases of the study. In the first phase, groups of 10 subjects each received placebo or misoprostol in doses of 200 micrograms, 100 micrograms, 50 micrograms, or 25 micrograms in a double-blind design. All misoprostol doses protected 50 to 70 percent of subjects as compared with 20 percent of subjects in the placebo group. To expand the number of observations, 90 additional subjects in groups of 30 each were evaluated after receiving misoprostol 50 micrograms or 25 micrograms or placebo. Misoprostol 50 micrograms protected 14 of 30 subjects (47 percent), 25 micrograms protected 11 of 30 (37 percent), and placebo protected six of 30 (20 percent). The dose-response trend was statistically significant (p less than 0.05). It is concluded that misoprostol protects the gastric mucosa against a single 1,300-mg dose of aspirin and that there is a significant dose-response relationship.

Adolescent↗
PubMed1987

Reduction of endoscopically assessed acute aspirin-induced gastric mucosal injury with cimetidine.

We studied the influence of cimetidine on the gastroscopically visible effects of a single 1296-mg dose of aspirin. An initial dose-response study in 48 subjects showed that 200- and 400-mg doses of cimetidine conferred a sufficient reduction in gastric mucosal injury to warrant further study. A second study showed that coadministration of a single 200- or 400-mg cimetidine tablet with the aspirin conferred the same degree of injury reduction as when cimetidine was given before the aspirin. Reduction in mucosal injury by a 200-mg cimetidine tablet, coadministered with four aspirin tablets, was then compared to placebo in a double-blind trial. A reduction of mucosal injury was observed in 14 of 20 (70%) subjects receiving cimetidine and 0 of 10 subjects receiving placebo (P less than 0.001). Two hundred milligrams of cimetidine is therefore a rational dose for further studies of the reduction of chronic aspirin-induced gastric mucosal injury.

Acute Disease↗
PubMed1987

Cross-sectional imaging method. A system to compare ultrasound, computed tomography, and magnetic resonance with histologic findings.

Studies comparing imaging modalities require a precise knowledge of the type and location of tissue structures. When comparing cross-sectional techniques such as ultrasound, computed tomography, and magnetic resonance imaging, the images must be obtained through the same tissue section that is examined histologically. An experimental system that permits comparison of these modalities with histologic sections of precisely corresponding tissue is described. Application in 30 gastrointestinal tissue specimens shows a high degree of correspondence between cross-sectional images and histologic sections. This method should be useful in tissue imaging research for anatomic correlation and for comparisons between imaging modalities.

Digestive System↗