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At least 1,513 records · Page 84Linked to original sources
PubMed1978

[The exhaled hydrogen test: its value in the quantitative diagnosis of carbohydrate malabsorption].

A study has been conducted to determine the accuracy of breath-H2 measurements for quantitating the malabsorption of small amounts of carbohydrate. H2 pulmonary excretion was measured after an overnight fast at 30-min intervals for 4 h in 7 healthy subjects after ingestion of 4 doses of lactulose (2.5,5,10 and 50 g). In 3 subjects the test was repeated without lactulose. The volume of H2 excreted was directly proportional to the amount of ingested lactulose: mean cumulative H2 excretion over a 2-h period after 5, 10 and 50 g was 2.9, 6.6 and 37.6 ml H2 respectively; H2 response after the 2.5-g dose was not perceptible. Individual H2 excretion before lactulose ingestion was highly variable: 0.096 +/- 0.075 mlH2 (mean +/- 1 SD); the individual base line rate over a fasting period showed marked fluctuations. It is concluded that the inter- and intraindividual variations of H2 excretion limit the accuracy of the H2 breath test for quantitating malabsorption of small amounts of carbohydrate.

Breath Tests↗
PubMed1981

In vivo lipid peroxidation: measurement via exhaled pentane and protection by vitamin E.

Lipid peroxidation occurs in animal tissue when antioxidant protective systems are lacking. Among the protective systems in animals are the biological antioxidant vitamin E and selenium-glutathione peroxidase, a decomposer of peroxides. Lipid peroxidation also occurs when a variety of chemical oxidants are introduced into a animal. The most recently developed technique for measurement of lipid peroxidation in vivo is the analysis of expired air for volatile hydrocarbon products of lipid hydroperoxide decomposition. Pentane is derived from the major fatty acids of the animal body, those of the omega 6-un-saturated fatty acid family, while ethane is derived from omega 3-unsaturated fatty acids. The technique of measuring volatile hydrocarbons has been used by a number of investigators to show increased lipid peroxidation in animals fed diets deficient in antioxidant nutrients and in animals exposed to ozone or injected with iron, halogenated hydrocarbons, or peroxides. Evidence that volatile hydrocarbons are produced during lipid peroxidation, the similarities of results obtained by different investigators who have measured lipid peroxidation by volatile hydrocarbon production, and the relative effects of nutritional and chemical treatments on production of volatile hydrocarbons by laboratory animals or humans are reviewed.

Fatty Acids, Unsaturated↗
PubMed1995

[Preliminary results using a combined xylose absorption/hydrogen exhalation test in horses].

In the present study the breath hydrogen (H2) excretion test was combined with the xylose absorption test in 4 normal horses and 9 clinical patients with chronic diarrhea (n = 3) or chronic weight loss without diarrhea (n = 6). All horses underwent a thorough clinical examination. Laboratory evaluations consisted of haematology and serum biochemistry as well as bacteriological and parasitological examination of feces. In addition, serum electrophoresis and abdominocentesis was performed in all the clinical patients. Gastroscopy was carried out in 6 patients and rectal biopsies were obtained from 4 animals. Two animals were euthanized within 4 weeks after the evaluation. The diagnosis of chronic granulomatous enteritis was confirmed in one of them at necropsy, the cause of weight loss in the other remained unexplained. In the remaining animals, specific causes such as management, parasites, chronic infections and diseases of liver, kidneys and heart were excluded, but no specific diagnosis could be obtained. For the combined xylose absorption/H2 excretion test, the animals were starved overnight and given 0.5/kg/bwt xylose as a 10% solution by stomach tube the next morning. Blood samples were collected for plasma xylose analysis at 30 min intervals for 4 hrs, and breath samples were also collected at 30 min intervals for 8 hrs. With the exception of the animal with granulomatous enteritis, the diseased horses showed only slight alterations in either peak concentrations or times to reach peak levels of plasma xylose. None of the healthy animals showed an increase in breath H2 production after xylose administration, whereas five of the diseased animals showed distinct increases of variable heights. In addition, the diseased horses showed higher fasting breath H2 levels (range 7.5-61.5 ppm) than normal horses (range 0-5 ppm). It is concluded that gastrointestinal disorders might be influenced or even induced by a change in intestinal microbial composition, as evidenced by an increased hydrogenic metabolism.

Animals↗
PubMed1996

[Acid-alcohol-resistant bacilli detected by microscopic analysis of exhaled air from HIV-infected patients: tuberculosis or mycobacteriosis?].

OBJECTIVES: The incidence of atypical mycobacterial infections has increased with the AIDS epidemic. To present, microscopic examinations of airway specimens positive for acid-fast bacteria were highly suggestive of tuberculosis. However, since the AIDS epidemic, certain authors have reported an increase in Mycobacterium avium intracellulare found in respiratory specimens. The aim of this work was to determine what factors might distinguish between these two infections revealed discovery of an acid-fact bacilli. METHODS: Hospital files of all HIV seropositive patients seen between November 1992 and March 1995 and with at least one airway specimen positive for acid-fast bacilli were studied retrospectively. RESULTS: Mycobacterium tuberculosis was isolated in 19 patients, Mycobacterium avium intracellulare in 8 and culosis and M. avium intracellulare. There was no difference for age, sex, geographical origin, transmission mode, antigen positivity, radiologic findings or clinical signs between patients with the different types of mycobacterium. The CD4 count was however significantly lower in patients with an atypical mycobacteriosis (14.5/mm3) than in patients with tuberculosis (91.7 +/- 83.7) (p = 0.004). CONCLUSION: These findings show that in HIV-infected patients with a CD4 count under 100/mm3, the presence of acid-fact bacilli can indicate either M. tuberculosis or M. avium intracellulare. Combined anti-tuberculosis and antimycobacteriosis therapy thus would appear to be justified until the germ can be identified.

AIDS-Related Opportunistic Infections↗