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Biomedical subjects

B Krevsky

Publications and source records attributed to B Krevsky.

At least 19 recordsLinked to original sources
PubMed1992

Effect of verapamil on human intestinal transit.

Although constipation is a well-known side effect of calcium channel blockers such as verapamil, this side effect has not been evaluated in a quantitative manner. In a double-blind, randomized, crossover trial, the effect of verapamil (240 mg/day) was compared to placebo in 15 normal male volunteers. Subjects recorded their bowel movements and any side effects. Scintigraphy was used to quantitate gastric emptying, small intestinal transit, and colonic transit. In the study period of four days, verapamil did not change the frequency, consistency, or passage of bowel movements. A significantly increased number of side effects was noted during verapamil treatment--notably abdominal pain and dry mouth. The slope of gastric emptying was not significantly different for verapamil (0.012 +/- 0.02) than for placebo (0.013 +/- 0.001). Distal ileum filling was also not different for verapamil (0.41 +/- 0.13%/min) than placebo (0.33 +/- 0.05%/min). Progression of the colonic geometric center was significantly delayed at 48 hr by verapamil (5.2 +/- 0.4 vs 6.2 +/- 0.23; P less than 0.01). This study suggests that the constipating effect of verapamil is due to a delay of colonic transit and not due to an effect on upper gastrointestinal transit.

Adult↗
PubMed1992

Gastrointestinal bleeding: improved localization with cine scintigraphy.

Studies of gastrointestinal bleeding, done with technetium-99m-labeled red blood cells were performed in 52 consecutive patients to determine whether cinematic acquisition and display localized sites of bleeding more accurately than did conventional static imaging. Computerized images were obtained for 15 seconds per image in 15-minute sets. Interpretations based on a cinematic display were compared with those based on standard 1-minute images obtained every 5 minutes. Pathologic confirmation of a site of bleeding was obtained in 21 patients. The cinematic display demonstrated bleeding not seen on static images and yielded either more accurate localization or increased sensitivity in eight of 21 patients (38%). Linear regression showed that the cinematic correlation (r = .98) to the actual site of bleeding was better than either of two readers' interpretations of the static display (r = .93, P less than .02; and r = .88, P less than .0004). The mean error for cinematic localization of bleeding (0.4 anatomic segments +/- 0.6 [standard deviation]) was less than that for the static interpretations (1.1 anatomic segments +/- 1.4) (P less than .01). It is concluded that computerized cinematic acquisition and display of scintigrams improves localization and detection of gastrointestinal bleeding.

Adult↗
PubMed1992

Effect of ethyl alcohol on motor function in canine stomach.

The aim of this study was to elucidate the effects of ethanol on gastric emptying and the trituration of solid food. With the use of a noninvasive physiological imaging technique, gastric processing of a radiolabeled solid meal was evaluated in unanesthetized dogs which ingested 6-8% ethanol solutions or received intravenous alcohol before the meal. Oral alcohol (resulting in blood levels up to 174 mg/dl) decreased the amplitude of antral contractions or completely abolished them. Alcohol did not significantly affect the fundamental frequency of contractions except at high doses, at which contractions were abolished. Alcohol lengthened the mean time to 50% of gastric emptying in a dose-dependent manner, from 132 +/- 3 min without alcohol to 160 +/- 10 min with oral alcohol at blood levels of 80-120 mg/dl (P less than 0.05). This was manifested by a lengthening of the lag phase, but there was no effect on the terminal slope of emptying (emptying rate) of the processed meal. At equal blood levels up to 120 mg/dl, orally administered alcohol had a more pronounced effect than intravenous alcohol. These data suggest that even low doses of dilute alcohol affect the ability of the antrum to process solid food and thereby contribute to impairment of gastric emptying.

Administration, Oral↗
PubMed1992

Flexible sigmoidoscopy screening in an industrial setting.

Little is known about the yield of colorectal cancer screening programs in an industrial setting. We therefore established a flexible sigmoidoscopy screening program at a chemical manufacturing plant and offered testing to all employees over the age of 40. After a Fleet enema preparation had been administered, a digital rectal examination and sigmoidoscopy were performed on each volunteer worker in the medical office of the plant. The plant had an average census of about 650 workers; 202 were screened during a 2-yr period. The mean (+/- SEM) age of participants was 52 +/- 0.4. Sixty-four employees had polyps (31.7%); data on follow-up colonoscopy were available in 69%. Colonoscopy revealed adenomatous polyps in 23 workers (53.5%), hyperplastic polyps in 10 (23%), and no evidence of neoplasia in 10 (23%). Seven workers did not arrange for follow-up colonoscopy and 12 individuals could not be contacted. No cancers were detected. In the 40- to 50-yr age group, polyps were detected in 19.5% of employees (25% adenomatous). Incidental findings were common, and included prostatic nodules, hemorrhoids, diverticulosis, and proctitis, among others. We conclude that screening sigmoidoscopy can be conveniently and economically performed at the workplace, with a high yield and good worker acceptance. The high yield suggests a possible association between polyp formation and work in a chemical plant. The finding of adenomatous polyps in the younger patients suggests that the threshold for flexible sigmoidoscopy at age 50 needs to be reassessed.

Adult↗
PubMed1991

Effects of selective opioid agonists on feline colonic transit.

The mu agonist morphine and the non-specific opioid antagonist naloxone both may accelerate feline colonic transit; the effects of morphine are dose dependent. Kappa and delta receptor function was studied in the present work. Colonic transit of a radionuclide marker instilled into the cecum was quantitated for 6 hr in a crossover study. The delta agonist [D-Pen2,D-pen5]enkephalin (1 mg/kg, i.m.) prolonged the cecum and ascending colon half-emptying time by 337% (P less than 0.05), and delayed the progression of the geometric center over time. The kappa agonist U-50,488 (1 mg/kg, i.m.) had no apparent effect on the cecum and ascending colon, but delayed filling of the descending colon. Loperamide, an antidiarrheal agent, also delayed colonic transit. Thus, selective opioid agonists have both site and functional differences in their effect on feline colonic transit.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1991

The effect of endoscopic laser therapy on survival in patients with squamous-cell carcinoma of the esophagus. Further experience.

Although endoscopic laser therapy is effective for symptom palliation in esophageal cancer, few studies have investigated its effect on survival. We previously reported a 300% improvement in survival in 10 patients with squamous-cell carcinoma of the esophagus after endoscopic Nd:YAG laser energy. We now report a study to determine if the survival advantage persisted after treating an additional 26 patients. Thirty-six patients with squamous-cell carcinoma of the esophagus treated with endoscopic laser therapy were compared to 20 controls identified by our hospital Tumor Registry. There was no difference between the groups with respect to age, sex, race, location of tumor, or clinical stage. More control patients (25%) had previously undergone surgery than laser patients (0%) (p less than 0.05). Survival analysis demonstrated a significant improvement in overall survival (p less than 0.05), with an improvement in median survival from 5.7 to 9.7 months (p less than 0.05). One-year survival was 38% in laser patients, compared to 20% in control patients. Our experience continues to demonstrate that endoscopic laser therapy is effective in prolonging life as well as palliating the symptoms of patients with squamous-cell esophageal carcinoma.

Carcinoma, Squamous Cell↗
PubMed1991

Comparison of left anterior oblique and geometric mean gastric emptying.

A left anterior oblique image (LAO) and the geometric mean of anterior and posterior counts have both been proposed as methods for acquiring gastric emptying data. Both approaches are used to correct for the changes in attenuation that occur as the depth of radiolabeled solids changes during gastric emptying. These two methods were compared by using a power exponential curve fit to calculate a lag phase, an equilibrium emptying rate, and a half-time for gastric emptying in 20 patients. There were no significant differences (mean +/- 1 s.e.m.) in the measured half-emptying time (115 +/- 10 versus 104 +/- 7 min) (p = 0.08) or rate of gastric emptying (0.015 +/- 0.002 versus 0.015 +/- 0.002 min-1) (p = 0.56) for LAO imaging versus the geometric mean. However, the LAO measurements of the lag phase were significantly higher (69 +/- 7 min) than the geometric mean (53 +/- 6 min) measurements (p = 0.004). This resulted in 4/20 (20%) of patients with normal geometric mean lag phase measurements who would have been reclassified as abnormal using the LAO method.

Female↗
PubMed1991

Idiopathic gastroparesis is associated with a multiplicity of severe dietary deficiencies.

UNLABELLED: Idiopathic gastroparesis (IG), a disorder characterized by abnormally delayed emptying of food from the stomach, is associated with many symptoms that could have an impact on dietary intake. The intake of dietary protein, carbohydrate, fat, fiber, vitamins, and minerals was prospectively evaluated in patients with symptomatic IG and compared with asymptomatic controls. Twenty-four patients and 24 age- and sex-matched controls completed a detailed 7-day diet record while consuming a self-selected diet. Dietary information was entered into a computer and analyzed using the Nutranal program. Results were expressed as daily intake and percent recommended dietary allowance (%RDA) when applicable. Patients consumed a diet containing fewer calories than would have been predicted based on age, height, sex, frame, and weight (85% of calculated energy expenditure vs 100%) for controls. Although patients with IG consumed significantly fewer calories than controls (1112 kcal vs 1431 kcal), the proportion of fat (32% vs 34%), carbohydrate (49% vs 48%), and protein (17% vs 16%) was similar in the two groups. Intake of vitamins B6, vitamin C, folate, niacin, riboflavin, thiamine, calcium, copper, iron, magnesium, phosphorus, and zinc were below the %RDA. Intake of vitamin B12, vitamin C, folate, thiamine, niacin, magnesium, phosphorus, and zinc were significantly less than controls. Vitamin A intake was above the RDA and not different from that of controls. Prolonged t1/2 of solids correlated with diminished intake of protein, iron, niacin, and potassium. They correlated inversely with serum albumin in patients with idiopathic gastroparesis. CONCLUSION: Although eating less, patients with IG do not consistently alter the proportion of fat, carbohydrate, and protein in their diets. Because their diet is markedly deficient in a number of essential vitamins and minerals, dietary evaluation and counseling is suggested for all patients with idiopathic gastroparesis.

Adult↗
PubMed1990

Evaluation of hematochezia.

Although etiologies are diverse, diagnosis can usually be made with a careful history and physical examination, plus selected radiographic or endoscopic studies. Colonoscopy also sometimes allows prompt, definitive therapy.

Diagnosis, Differential↗
PubMed1990

Failure of (+)-naloxone to accelerate feline colonic transit.

To determine whether the colonic transit accelerating effect of (-)-naloxone (0.3 mg/kg, i.m.) is due to an action at opioid receptors or a direct pharmacologic effect, its enantiomer, (+)-naloxone (0.3 mg/kg, i.m.), was administered to cats and compared to saline control using colonic transit scintigraphy. Transit was not accelerated by (+)-naloxone. The effects of naloxone on colonic transit are thus stereospecific, and are probably mediated by opioid receptors.

Animals↗
PubMed1990

Feline cholescintigraphy. Studies on role of cholecystokinin in regulation of gallbladder function.

Quantitative cholescintigraphy using technetium-99m-disofenin was employed to study the kinetics of gallbladder filling and emptying in cats. The radionuclide rapidly visualizes the gallbladder, with activity continuing to rise during the 60 minutes after injection. The gallbladder emptied in a dose-response manner to the intravenous administration of the octapeptide of cholecystokinin (CCK-OP). An infusion of 10 ng/kg/min of CCK-OP resulted in 75% emptying of the gallbladder at 30 min compared to control. This was significantly greater emptying than with an infusion of either 0.1 or 1.0 ng/kg/min. After administration of a fatty meal, the 30-min gallbladder emptying was 73% of control, similar to the response to CCK-OP at a dose of 10 ng/kg/min. Intravenous administration of 1 mg/kg of L-364,718 (a CCK-receptor antagonist) completely inhibited the gallbladder response to a fatty meal but had no effect on gallbladder filling in the fasting state. These results suggest that feline cholescintigraphy can be used for the quantitative study of gallbladder emptying. While CCK appears to be the primary modulator of gallbladder contraction after a fatty meal, no influence of CCK was detected in the interdigestive (fasting) state.

Animals↗
PubMed1989

Effects of morphine and naloxone on feline colonic transit.

The effects of endogenous and exogenous opioid substances on feline colonic transit were evaluated using colonic transit scintigraphy. Naloxone (0.3 mg/kg, i.m.) accelerated emptying of the cecum and ascending colon, and filling of the transverse colon. Endogenous opioid peptides thus appear to play a significant role in the regulation of colonic transit. At a moderate dose of morphine (0.1 mg/kg, i.m.), cecum and ascending colon transit was accelerated, while at a larger dose (1.0 mg/kg, i.m.) morphine had no effect. Since naloxone, a relatively nonspecific opioid antagonist, and morphine, a principally mu opioid receptor agonist, both accelerate proximal colonic transit, a decelerating role for at least one of the other opioid receptors is inferred.

Animals↗
PubMed1989

Scintigraphic evaluation of gastric emptying: are radiolabeled solids necessary?

A standard, dual-isotope meal (Tc-99m-egg sandwich and In-111 DTPA in water) was administered to 14 normal volunteers and 37 patients, who had not undergone gastric surgery, to determine if the emptying characteristics of the liquid phase alone could accurately predict delayed solid emptying. Delayed gastric emptying was defined clinically as a solid half-emptying time more than two standard deviations greater than the mean for normal volunteers. Linear regression analysis was performed on the natural logarithm of liquid fractional retention at each time interval to yield a slope and y-intercept for each subject. There was no significant difference (0.6 less than P less than 0.8) between volunteers and patients with normal solid emptying for the liquid slope. In patients who exhibited delayed gastric emptying for solids, the liquid slopes were significantly different from the normal values (P less than .001). There was a high correlation of liquid slope to solid half-emptying time in all patients and volunteers (r = -0.80, P less than .001). Comparison of the liquid slope measurement to solid half-emptying time criteria revealed a sensitivity of 96%, a specificity of 100%, and a predictive value of 100% for the slope test. These results suggest that delayed gastric emptying can be accurately detected with a liquid-solid meal using only a single-liquid label.

Adult↗