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Biomedical subjects

M B Kimmey

Publications and source records attributed to M B Kimmey.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Appendiceal US scans: histologic correlation.

High-resolution in vitro ultrasonography (US) of 20 surgical appendiceal specimens was performed to compare appearances of appendiceal tissue at US with corresponding histologic features. With an articulated-arm system and micropositioner, precise spatial correlation was achieved. As elsewhere in the gastrointestinal tract, five distinct echo layers were observed. Normal and inflamed specimens demonstrated these layers, but the architecture became disorganized and indistinct in cases of appendicitis. Three measurements were made for each specimen: (a) overall cross-sectional diameter, including the lumen, (b) thickness of the submucosal echo layer, and (c) the combined thickness of both walls, excluding the lumen. For the inflamed specimens, a substantial increase in the thickness of the summed wall measurements was found. Wall US appearance alone may be misleading in differentiation of normal and abnormal appendices.

Adolescent↗
PubMed1992

NSAID, ulcers, and prostaglandins.

The pathogenesis of nonsteroidal antiinflammatory drug (NSAID) induced gastrointestinal (GI) injury is complex and includes contributions from direct topical injury and reduced mucosal resistance due to indirect or systemic inhibition of mucosal prostaglandin (PG) synthesis. Some NSAID that cause less inhibition of gastroduodenal PG synthesis appear to cause less GI injury. NSAID induced GI complications include adverse symptoms, endoscopically observable mucosal damage, and ulcer complications. Ulcers are common in patients taking NSAID and are often asymptomatic; however, they may bleed or perforate. Prevention of GI complications can be approached by concomitant administration of a protective drug or by developing a safer NSAID. However, limitations of concomitant therapy with existing protective drugs suggest that new NSAID should be developed that are less harmful to the GI tract.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1990

Prevention of further recurrences of Clostridium difficile colitis with Saccharomyces boulardii.

A patient with six documented episodes of recurrent Clostridium difficile colitis over an eight-month period is described. Relapses of colitis occurred despite treatment with vancomycin, metronidazole, bacitracin, and cholestyramine. Each recurrence appeared to begin successively closer to the end of the previous course of treatment. Four episodes were sufficiently severe to require hospitalization for rehydration. Saccharomyces boulardii, a nonpathogenic yeast, was begun prior to discontinuing vancomycin therapy for the last recurrence and was continued for three months. Serial stool cultures and assays for C. difficile showed persistence of the organism but rapid reduction of high titers of cytotoxin. No further recurrences of diarrhea or colitis were encountered while the patient was taking Saccharomyces boulardii and for 18 months of follow-up after the yeast was discontinued.

Aged↗
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↗
PubMed1989

Reduction of indomethacin induced gastroduodenal mucosal injury and gastrointestinal symptoms with cimetidine in normal subjects.

A study was performed in 57 healthy volunteers to determine the effectiveness of cimetidine on reducing gastrointestinal (GI) mucosal lesions and symptoms induced by indomethacin. Endoscopic evidence of gastroduodenal injury and various GI symptoms appeared within 4 days after initiation of indomethacin therapy (50 mg TID) alone. Concomitant therapy with cimetidine, either 200 mg QID or 400 mg BID reduced the incidence of gastric erosions by up to 25% and duodenal erosions by up to 44% (gastric erosions from 81 to 61 and 78%, and duodenal erosions from 90 to 50 and 61%). The incidence of gastric ulcers was reduced from 24 to 0 and 6%, and of duodenal ulcers from 14 to 0 and 11%). The occurrence of moderate or severe pain was also significantly less with coadministration of cimetidine. Results from our study suggest that cimetidine may provide an effective prophylactic therapy against both NSAID related symptoms and gastroduodenal mucosal lesions.

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

Colorectal neoplasms: accuracy of US in demonstrating the depth of invasion.

Six normal and 16 neoplastic colorectal specimens were examined with 8.5-MHz ultrasound (US). An articulated system facilitated precise spatial correlation between US and histologic sections. Images were blindly interpreted and then compared with histologic results. All six normal specimen showed five distinct echo layers and were distinguished from neoplastic specimens by all the observers. The central echogenic layer, corresponding to the submucosa, is useful in determining the depth of origin of a neoplasm and the presence of submucosal invasion. US had an accuracy of 92.5% in demonstrating invasion of the submucosa and 77% for invasion of the muscularis externa. For mucosal neoplasms with invasion through the muscularis externa and extension into the subserosal tissues, nearly 90% of US interpretations were correct. High-frequency US may be useful in determining the depth of invasion of mucosal tumors with respect to the submucosa and in differentiating mucosal from extramural masses.

Biopsy↗
PubMed1986

Gastric protection by misoprostol against 1300 mg of aspirin. An endoscopic study.

Misoprostol, a synthetic prostaglandin E1 analog, is being evaluated in the treatment of peptic ulcer. It has been reported to have both antisecretory and cytoprotective properties. In this placebo-controlled, double-blind study, pretreatment with 200-micrograms doses of misoprostol was evaluated in the prevention of gastric injury caused by aspirin. Five oral doses of misoprostol or placebo were administered over 24 hr followed by a single oral 1296-mg dose of aspirin 30 min after the fifth dose of test agent. Two hours later the gastric mucosa was examined with a small-caliber fiberendoscope. Protection was defined as no more than 10 petechiae and no more than two hemorrhagic streaks in the gastric mucosa. Twenty of 30 (67%) subjects who received misoprostol was protected, whereas only one of 30 (3%) subjects receiving placebo was protected. The difference between the effects of misoprostol and placebo was highly significant (P less than 0.001). We concluded that five 200-micrograms doses of misoprostol given over 24 hr protects the gastric mucosa from the injurious effect of a single dose of aspirin.

Adolescent↗
PubMedDate not supplied

Endoscopic ultrasonographic findings in benign and malignant diseases of the stomach.

Endoscopic ultrasonographic (EUS) imaging was performed to examine the depth, extent and tissue character of gastric lesions in nine patients. Two patients with linitis plastica had endoscopically normal gastric mucosa, but a thickened gastric wall showing loss of normal layer structure on examination with EUS. In four patients the internal structure of gastric polyps could be imaged, showing the relationship to the gastric wall layers. EUS demonstrated the depth of gastric ulcers in three patients. Abnormalities in the echogenicity of the gastric wall adjacent to the ulcers were observed. EUS provides a three-dimensional endoscopic and ultrasonographic picture of the gastric mucosal surface and underlying wall, providing structural information not otherwise obtainable without examining the resected tissue.

Adult↗