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Biomedical subjects

Y Peled

Publications and source records attributed to Y Peled.

At least 73 records · Page 4Linked to original sources

Is human methane production affected by long-term occupational exposure to a methanogenic flora?

The factors determining human methane production or nonproduction are unknown. Exposure at a young age to a methanogenic flora is thought to be of significance. We examined whether long-term occupational exposure to methanogenic flora in adult life affects methane production. Among 38 subjects who worked in a cowshed for a mean period of 14 +/- 15 years, the proportion of methane producers was identical to that found in well-matched controls. The length of work in the cowshed had no effect on methane production.

Adolescent↗

Lactose malabsorption is not a cause of diarrhea during phototherapy.

Lactose malabsorption is not a cause of diarrhea during phototherapy. Jaundiced neonates under phototherapy develop diarrhea or loose stools during the treatment. These phenomena were attributed to an induced lactase deficiency caused by bilirubin breakdown products. We investigated lactose malabsorption in 59 neonates--29 normals and 30 jaundiced under phototherapy. Five-hour hydrogen breath tests were performed. Preprandial and postprandial (at 30, 60, 120, 180, 240, and 300 min) expired air samples were analyzed for hydrogen. Ten controls and five jaundiced neonates had positive hydrogen breath tests. Eighteen controls and 16 neonates under phototherapy had preprandial hydrogen (concentrations above 5 ppm). In our hands, lactase deficiency and lactose malabsorption were not induced by phototherapy. Lactase deficiency is therefore not the cause of diarrhea associated with phototherapy.

Breath Tests↗

The development of methane production in childhood and adolescence.

Methane concentration in the expired air was analyzed in 393 infants, children, and adolescents. There was no methane production below the age of 3 years. In the age group 3-4 years, 6.4% of the children produced methane. The percentages were 14.3-18.2% in children aged 7-14. A rise in methane production to 39.4-45.9% was recorded from age 14 to 18, as compared with 49.4% in adults in Israel. The reasons for these changes in methane production with age are not known. Alterations in the colonic flora or the production of a specific substrate(s) are the main possibilities. In our opinion, the latter possibility deserves further investigation.

Adolescent↗

Measurement of intestinal permeability using 51Cr-EDTA.

Intestinal permeability tests are a new class of tests of which the 51Cr-EDTA seemed the easiest to perform. We have evaluated the 8- and 24-h urinary excretion of ingested 51Cr-EDTA in 38 subjects. Twenty-seven patients with diseases not affecting the integrity of the small bowel served as controls. The test group consisted of two patients with celiac, six with Crohn's disease, and three with ulcerative colitis. Nineteen (70.37%) of the control patients had an abnormal test (more than 2.6% in 24 h). The patients with ulcerative colitis had normal excretion (mean 1.95% in 24 h). The patients with celiac disease had an elevated excretion (mean 3.62% in 24 h) and five out of six patients with Crohn's disease also had an increased excretion (mean 6.2% in 24 h). The elevated 51Cr-EDTA excretion in the control patients casts serious doubts on the validity of the test. Possible causes for abnormal excretion in the controls include various medications used by the patients as well as changes in the chromatographic mobility of 51Cr-EDTA, demonstrated by us after incubation with gastric juice.

Adolescent↗

Lactose malabsorption in Israeli children.

Lactose malabsorption during childhood was studied in 110 Jewish children in Israel, using the lactose hydrogen breath test. Sixty-eight subjects (61.8%) were lactose malabsorbers, 41 (60.3%) of whom were lactose-intolerant with symptoms evidenced during or following the tests, whereas 27 (39.7%) were symptom-free (tolerant malabsorbers). In the youngest age-group (4 months to 3 years), no lactose malabsorption was detected, whereas in the higher age-groups the prevalence of lactose malabsorption increased with age. The percentages of lactose malabsorption in the age-groups 3 to 6, 6 to 12 and 12 to 16 years were 56.5, 65.2 and 75.0%, respectively. The percentages of lactose-intolerant subjects also increased in the same age-group, to 26.5, 39.1 and 65.0%. There were no significant differences in lactose malabsorption and tolerance between the various ethnic groups tested. The peak values of breath hydrogen were higher in lactose-intolerant than in lactose-tolerant malabsorbers.

Adolescent↗

The cholyl glycine-1-14C breath test in various gastrointestinal disorders.

The cholyl glycine-1-14C breath test was evaluated in a variety of gastrointestinal disorders. 138 tests were performed in 106 patients. Methods of data expression were evaluated and the cumulative 8-hour value was used. In 27 control patients the upper limit of the normal was found to be 78. A good correlation was found between the peak values and the cumulative 8-hour values (r = 0.95, p less than 0.01). The reproducibility of the test was good (r = 0.985, p less than 0.05). Abnormal results were found in 12 out of 13 cases with resection of the ileum and 11 out of 14 cases with Crohn's disease of the distal small bowel. The test was normal in cases with diseases of the proximal small bowel (celiac, Whipple's and Chron's diseases). The test was also normal in patients with colitis. It was abnormal in some of the cases after cholecystectomy and in most cases with carcinoma of the pancreas. The breath test was useful in monitoring the results of treatment in bacterial overgrowth of the small bowel. False negative results were observed after antibiotic treatment. The method seems to be more sensitive than the Schilling test in diagnosing disease of the distal small bowel.

Adolescent↗

Alterations of the colonic flora and their effect on the hydrogen breath test.

The hydrogen breath test was performed by ingestion of 20 g lactulose and analysis of end-expiratory air. Eighteen patients undergoing colonoscopy, 17 receiving antibiotics, 12 prepared for colon surgery, and 15 controls were examined. The test was repeated under control conditions in the treated patients. Eleven of 55 subjects failed to produce significant amounts of hydrogen under control conditions. This 20% proportion of non-hydrogen producers is much higher than that reported by other investigators. The hydrogen production was very markedly depressed after preparation for colonscopy and antibiotic therapy. The effect of neomycin and enemata as used in preparation for colon surgery was less marked. Hydrogen production by the colonic flora is thus subject to individual variations and may be affected by various therapeutic regimens. All these may cause false negative results when using the hydrogen breath test to evaluate carbohydrate absorption. The test should therefore not be performed for a considerable time after therapeutic manipulation of the colonic flora.

Adolescent↗

Is the fat breath test effective in the diagnosis of fat malabsorption and pancreatic disease?

An attempt was made to evaluate the diagnostic effectiveness of the 14CO2-tripalmitin breath test in the screening or diagnosis of fat malabsorption. The differential absorption of 14C-tripalmitin and palmitic acid was evaluated in the diagnosis of pancreatic insufficiency. 24 controls, 13 patients with steatorrhea and 6 with pancreatic disease (4 of them with sufficiency) were studied. 81 breath tests were performed using 75 ml sour cream as a carrier. In 11 cases the 14C-tripalmitin test was repeated using 27 g corn oil as carrier. Both the 14C-tripalmitin and 14C-palmitic acid breath tests failed to provide any discrimination between normals and patients with fat malabsorption. Variation in type and amount of the carrier fat did not alter these results. 14C-tripalmitin absorption was distinctly abnormal in the patients with pancreatic insufficiency. The differential absorption of 14C-tripalmitin and 14C-palmitic acid provided an even better separation between patients with and without pancreatic disease. In contrast to some other investigators we did not find the 14C-tripalmitin and/or palmitic acid breath tests useful in the diagnosis or screening of fat malabsorption. These tests appear promising in the diagnosis of pancreatic disease.

Adolescent↗