Showing papers on "Breath test published in 1988"

Carbon-14 Urea Breath Test for the Diagnosis of Campylobacter Pylori Associated Gastritis

Abstract: Urease in the human gastric mucosa is a marker for infection with Campylobacter pylori (CP), an organism suspected of causing chronic gastritis and peptic ulceration. To detect gastric urease, we examined 32 patients who were being evaluated for possible peptic ulcer disease. Fasting patients were given 10 microCi (370 kBq) of 14C-labeled urea. Breath samples were collected in hyamine at intervals between 1 and 30 min. The amount of 14C collected at these times was expressed as: body weight X (% of administered dose of 14C in sample)/(mmol of CO2 collected). The presence of C. pylori colonization was also determined by examination of multiple endoscopic gastric biopsy specimens. On average, patients who were proven to have C. pylori infection exhaled 20 times more labeled CO2 than patients who were not infected. The difference between infected patients and C. pylori negative "control" patients was highly significant at all time points between 2 and 30 min after ingestion of the radionuclide (p less than 0.0001). The noninvasive urea breath is less expensive than endoscopic biopsy of the stomach and more accurate than serology as a means of detecting Campylobacter pylori infection. Because the test detects actual viable CP organisms, it can be used to confirm eradication of the bacterium after antibacterial therapy.

Jejunal mucosal architecture and fat absorption in male homosexuals infected with human immunodeficiency virus.

Abstract: Diarrhoea and weight loss are common features of human immunodeficiency virus (HIV) disease. The mechanism of diarrhoea occurring in the absence of known enteropathogens is currently unknown. We have measured fat absorption, using the 14C triolein breath test, and quantitatively assessed jejunal villous architecture in 20 male homosexuals at various clinical stages of HIV disease. Enteropathogens were not detected in any subject at the time of jejunal biopsy in stool or jejunal mucosa. Partial villous atrophy was the sole histological abnormality and was detected at any clinical stage of HIV disease. The 14C triolein breath test quantitatively correlated with the degree of jejunal villous atrophy. In addition subjective presence of diarrhoea was related to the detection of fat malabsorption. Thus diarrhoeal disease in HIV infected patients in the absence of enteropathogens may be due to jejunal enteropathy and may be present at early clinical stages of HIV disease.

Acidic colonic microclimate--possible reason for false negative hydrogen breath tests.

Abstract: About 5% of normal subjects fail to produce increased hydrogen breath concentration after ingestion of the non-digestible carbohydrate lactulose (low hydrogen producers). The existence of low hydrogen producers limits the diagnostic use of hydrogen (H2) breath tests. We studied the effects of lactulose and of magnesium sulphate (MgSO4) pretreatment on stool-pH and on hydrogen exhalation after oral loading with lactulose or lactose in 17 hydrogen producers and 12 low hydrogen producers. In seven hydrogen producers acidification of stool pH by lactulose pretreatment (20 g tid) decreased hydrogen exhalation and three of seven (43%) became low hydrogen producers. In contrast, after pretreatment of eight low hydrogen producers with magnesium sulphate (5 g twice daily) all eight produced hydrogen after a lactulose load. Similarly four lactose intolerant low hydrogen producers had abnormal lactose hydrogen breath tests after MgSO4 pretreatment. MgSO4 pretreatment neither resulted in false positive lactose hydrogen breath tests in five lactose tolerant hydrogen producers, nor increased the hydrogen exhalation in five additional hydrogen producing controls after ingestion of lactulose. The results of these studies confirm that hydrogen production from lactulose decreases when the colonic pH is lower (lactulose pretreatment), and increases when colonic pH is higher (MgSO4 pretreatment). In low hydrogen producers the lacking increase of H2 exhalation after ingestion of non-digestible carbohydrates can be overcome by MgSO4 pretreatment, thus increasing the sensitivity of the test by avoiding false negative hydrogen breath tests in low hydrogen producers with disaccharide malabsorption or maldigestion. The underlying mechanism of this remarkable effect of MgSO4 pretreatment warrants further investigation.

Maturation of caffeine N-demethylation in infancy: a study using the 13CO2 breath test.

Abstract: Four premature neonates and eight infants 1–19 months old received caffeine for apnea The usual morning oral dose was substituted by 1,3,7 13C-trimethylxanthine (13C-tri CAF) as the citrate salt Five breath samples were collected the day before (day 1) and the day of 13C-tri CAF administration (day 2) Plasma (after each breath collection) and urine were collected on day 213C-CO2 exhalation was determined by isotope ratio mass spectrometry Caffeine and its metabolites were measured using high-pressure liquid chromatography Assessment of the labeled CO2 in the breath revealed no detectable 13C-tri CAF N-demethylation activity in infants before 45 wk postconceptional age However, demethylation (as urinary metabolites) has been detected before that age Two-, 4-, and 6-h cumulative excretion of 13C-tri CAF as 13C-CO2 increased with postnatal age and correlated with caffeine plasma clearance (r = 0840, p < 001) These results were consistent with those obtained for urinary metabolites In one infant (19 months old) the cumulative excretion of 13C-CO2 while crying was 65% of the value observed during quiet breathing The measurement of caffeine demethylation using the caffeine CO2 breath test is feasible in infants and is a safe and noninvasive method to determine age related changes in P4501-dependent N-demethylase activity

The 30-Minute Aminopyrine Breath Test: Optimization of Sampling Times after Intravenous Administration of 14C-Aminopyrine

Abstract: In a retrospective analysis of 78 well-defined patients, the procedure of the aminopyrine breath test was evaluated. After intravenous administration of 14C-aminopyrine (1.5 μCi, 1 mg)

A carbon-13 breath test to characterize glucose absorption and utilization in children.

Abstract: Summary After the administration of a 59% glucose-water solution that contained tracer amounts of the stable non-radioactive isotope 13C, breath samples were collected from five children with congenital glucose-galactose malabsorption and five with severe small bowel villous atrophy and chronic diarrhea. The 13CO2, breath test curves of the children with the congenital malabsorption and chronic diarrhea were compared with each other and with those from three healthy children and four infants with severe malnutrition but no diarrhea. The breath test curves from the children with glucose-galactose malabsorption and from those with diarrhea were significantly different from those of the other two groups, a finding consistent with impairment of glucose absorption. The [13C]glucose breath test clearly identified the children with severe glucose malabsorption. Further studies are required to determine whether less severe cases of carbohydrate malabsorption also can be identified using the parameters described in our study.

Repeatability of lactulose hydrogen breath test in subjects with normal or prolonged orocecal transit.

Abstract: The within-subject repeatability of orocecal transit assessed with lactulose hydrogen breath test was evaluated in 15 healthy volunteers and 16 constipated or obese patients. The test was repeated twice in each subject. Mean (sd) transit time was 105 (63) and 103 (60) min in the first and second series of tests, respectively, showing that the first measurement did not affect the second. The within-subject repeatability of the test was related to the length of transit, the scatter of the differences between the first and second test being greater with the increase of the mean gastrointestinal transit time. The 95% coefficient of repeatability was 84 min for all measurements and 30 and 118 min, respectively, for transit times under and over 100 min. The lowest reproducibility of the test was found in constipated patients with prolonged orocecal transit.

Method to prevent neonatal jaundice

Abstract: Disclosed herein is an effective and safe method for preventing the onset of neonatal jaundice through the reduction of bilirubin production. This method can be applied to populations of infants based on mass screening procedures predictive of development of the disease. The most effective of these screening methods measures carbon monoxide production by the infants using a simple breath test.

Abnormal 13C-Fatty Acid Breath Tests in Patients Treated With Valproic Acid

Abstract: Breath tests using fatty acids labeled with a stable isotope (carbon 13) were carried out on epileptic patients treated with valproic acid in order to detect abnormal fatty acid metabolism. The patients were given 13C-octanoic acid or 13C-palmitic acid orally, and expired air was collected at appropriate intervals for the analysis of 13CO2 content by a mass spectrometer. Eight patients were tested in the palmitic acid breath test and nine patients in the octanoic acid breath test. Controls for these tests were patients treated with antiepileptic drugs other than valproic acid and unmedicated cerebral palsy patients. In the valproic acid-treated group, 13C recovery was reduced by 56% in seven hours on the 13C-palmitic acid breath test, while the octanoic acid breath test showed a 52% reduction in one hour. This suppression of fatty acid oxidation was significantly correlated with dose of valproic acid in both tests. No influence of other drugs was detected, and the effect of administered carnitine was not conclusive. This study demonstrates the usefulness of 13C-labeled fatty acid breath tests in clinical practice.

Developmental changes of lactose malabsorption in normal Chinese children: a study using breath hydrogen test with a physiological dose of lactose.

Abstract: The malabsorption of a physiological dose of lactose (0.5 g/kg body weight) was studied in 726 healthy Chinese children, ranging in age from 3 to 18 years, using the breath hydrogen test. The prevalence of lactose malabsorption was found to increase with age; it occurred in less than 15% of preschool-age children and in approximately 45% of younger school-age and 60% of older school-age children. Approximately 70% of adolescents measured showed malabsorption. The critical period of change was from 6 to 7 years of age, with the lactose malabsorption rate rising abruptly from 12 to 43%. The incidence of lactose intolerance in teenagers and adolescents was 27 and 33%, respectively. The great majority of them had only dull abdominal pain. No case of lactose intolerance was seen in children less than 9 years of age. These results indicated that preschool Chinese children can absorb a physiological dose of lactose (equivalent to the average amount of milk consumed daily) without any adverse effects. In contrast, one half of school-age children and two thirds of adolescents were malabsorbers.

Measurement of 13C-glucose oxidation rate using mass spectrometric determination of the CO2: Ar ratio and spirometry

Abstract: A new method was developed and validated for measuring the CO2 concentration in the breath by mass spectrometric analysis. Argon, an inert gas that is present in air in a constant concentration of 0.923%, was used as an internal standard. By determining the ratio of CO2 (mass 44) to Ar (mass 40) in a breath sample, it was possible to read the CO2 concentration from a standard curve, relating CO2 concentration to CO2: Ar ratio. By combining mass spectrometric determination of CO2 concentration in breath with spirometric measurement of expired volumes, the CO2 production was determined in 67 subjects at rest. The mean value was 8.86 mmol kg-1 h-1, but there was considerable interindividual variation. This new method was applied to glucose oxidation studies in 10 normal subjects, 10 post-gastrectomy patients and 7 obese type II diabetic subjects. Measurement of the 13CO2 exhalation with quantitative determination of CO2 production allowed more accurate determination of the CO2 excretion rate in relation to blood levels of glucose, insulin and free fatty acids than assuming the constant CO2 production of 300 mmol unit body surface -1 h-1 or 9 mmol kg-1 h-1. It also resulted in a better discrimination between normal subjects and diabetics.

The aminopyrine breath test for the evaluation of liver function in alcoholic patients: drug pharmacokinetics and environmental factors.

Abstract: Drug pharmacokinetics and environmental factors contribute to the selection of an ideal drug substrate for the determination of liver function via the carbon dioxide breath test. An ideal drug should be rapidly absorbed, and have an hepatic extraction ratio between 0.2 and 0.5. Its metabolism should not be induced by ethanol or be affected by cigarette smoking. The relative promise of caffeine and methacetin are compared to aminopyrine.

The Effect of MCT Oil Supplement in Very Low Birth Weight Infants, with Evaluation by the 13C-Labeled MCT Breath Test

Abstract: We studied the efficacy of medium-chain triglyceride (MCT) as an energy source in premature infants. Infants who were given 3 g/kg/day of MCT oil gained body weight better than the control group in spite of a smaller water intake. This is advantageous to premature infants who need water restriction due to patent ductus arteriosus (PDA), bronchopulmo nary dysplasia (BPD), etc. We also proved that MCT oil is rapidly absorbed and digested, by means of the 13C-trioctanoin breath test.

Synthesis of [13C]phenacetin and its application to the breath test for the diagnosis of liver disease.

Abstract: N-(4-([1-13C]Ethoxy)phenyl)acetamide (13C-phenacetin) was prepared by two methods. In the first method, p-nitrophenol was alkylated with [1-13C]iodoethane and reduced to give 4-([1-13C]ethoxy)aniline (13C-p-phenetidine), which was acetylated with acetic anhydride to give 13C-phenacetin. In the second method, N-acetyl-p-aminophenol was alkylated with [1-13C]iodoethane. By using an excess amount of the starting material, [1-13C]iodoethane was convrted to 13C-phenacetin in high yield. The 13C-phenacetin thus obtained was applied to the breath test, and could be detected by 13CO2 analyzer. Thus, the 13C-phenacetin breath test should be applicable to the diagnosis of liver disease.

Metabolic and nutritional parameters in patients after colonic polypectomy.

Abstract: Breath methane and hydrogen, plasma acetate, serum selenium, vitamin A and beta-carotene were measured in 47 patients from whom colonic polyps had been removed by endoscopic polypectomy between 3 months and 2 years previously. Patients were compared with 39 control subjects in whom no abnormality was detected during colonoscopy. The proportion of methane exhalers was significantly (p less than 0.0005) higher in patients after polypectomy (66.0%) than in controls (28.2%). Mean plasma acetate was lower (p less than 0.025) in post-polypectomy patients (70.5 microM) than in control subjects (97.1 microM) while breath hydrogen was similar in both groups. The serum concentrations of the antioxidants selenium and beta-carotene showed no differences between the groups whereas vitamin A was higher (p less than 0.01) in serum samples of patients after polypectomy than of controls. These findings indicate that the colonic environment in post-polypectomy patients exhibits certain characteristics which may be related to the formation of benign tumors and possibly colon cancer.

Triolein breath test of fat absorption in patients with chronic liver disease.

Abstract: We have compared the [14C]triolein breath test for fat malabsorption with fecal fat excretion corrected for marker pellet recovery in 23 subjects with chronic liver disease. The breath test identified 15 of the 17 subjects with abnormal fecal fat excretion (sensitivity 88%). However, four of the six subjects with normal fecal fat excretion gave abnormal breath test results (specificity 33%). While three of the four subjects with falsely abnormal breath tests had alcoholic liver disease, the explanation for the low specificity is unclear and may not be confined to patients with alcohol-related disease. We are therefore unable to recommend the breath test as a screen for steatorrhea in patients with chronic liver disease.

Experience with 14C-Urea Breath Test in Detecting Campylobacter pylori

Abstract: Campylobacter pylori has been isolated world-wide from gastric mucosal biopsies of patients with non-ulcer dyspepsia, duodenal or gastric ulcer and those of asymptomatic individuals, virtually exclusively when chronic active gastritis was present [1–10]. Although the precise role of C. pylori in any of these conditions remains unclear, there is growing evidence for a direct causal relationship to gastritis [11–14].

The antipyrine breath test in the rat: a pharmacokinetic model.

Abstract: Breath tests have been widely advocated for use as non-invasive probes of mixed function oxidase activity in vivo. A catenary sequence of events begins with demethylation and results in the exhalation of14CO2. Intermediates in this chain include formaldehyde and formate. In this current study [14C]-antipyrine, [14C]-formaldehyde and [14C]-formate have been administered to rats. The data from these one carbon intermediates lead to the conclusion that demethylation is not the rate-limiting step in the antipyrine breath test in the rat. The resultant14CO2 exhalation rate time profiles have been used to derive a compartmental pharmacokinetic model for the antipyrine breath test in the rat. The simplest catenary model (Antipyrine → formaldehyde formate → CO2) did not adequately describe the observed data. A compartment in equilibrium with the central compartment for formate was needed to characterize fully the observed data. The derived compartmental model was able to predict qualitatively the effects of phenobarbitone induction on the antipyrine breath test. The quantitative agreement between the model prediction and the observed data could be improved by incorporating the changes in one carbon metabolism produced by phenobarbitone.