Showing papers on "Breath test published in 1994"

Interpatient heterogeneity in expression of CYP3A4 and CYP3A5 in small bowel. Lack of prediction by the erythromycin breath test.

Abstract: The CYP3A subfamily of cytochromes P450 metabolize many medications and environmental contaminants. CYP3A4 and, in 25% of patients, CYP3A5 seem to be the major CYP3A genes expressed in adult liver. Hepatic levels of CYP3A4 can be estimated by the erythromycin breath test and vary at least 10-fold among patients. CYP3A4 has also been shown to be present in small bowel where it is responsible for significant "first-pass" metabolism of orally administered substrates. However, it is not known whether there is significant interindividual variability in the intestinal expression of CYP3A4, or whether the liver and intestinal catalytic activities of CYP3A4 correlate within an individual. It is also not known whether CYP3A5 is expressed in the small intestine. To address these questions, we administered the erythromycin breath test to 20 patients and obtained biopsies from their small bowel. There was a 6-fold variation in CYP3A catalytic activity (midazolam hydroxylation), an 11-fold variation in CYP3A4 protein content, and an 8-fold variation in CYP3A4 mRNA content in intestinal biopsies. There was an excellent correlation between intestinal CYP3A4 protein level and catalytic activity (r = 0.86; p = 0.0001); however, neither parameter significantly correlated with hepatic CYP3A4 activity as measured by the erythromycin breath test result (r = 0.27; p = 0.24 and r = 0.33; p = 0.15, respectively). We also found that CYP3A5 protein was readily detectable in biopsies from 14 (70%) of the patients, indicating that CYP3A5 is commonly expressed in human small intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Simple and reliable CYP1A2 phenotyping by the paraxanthine/caffeine ratio in plasma and in saliva

Abstract: Several procedures to monitor CYP1A2 activity in vivo by the use of caffeine as a probe have been proposed. They comprise caffeine clearance, based on both plasma and saliva concentrations, urinary metabolite ratios, the 13C-caffeine breath test, and the paraxanthine/caffeine ratio in plasma. The la

Combined Carbon-13-Glycine/Carbon-14-Octanoic Acid Breath Test to Monitor Gastric Emptying Rates of Liquids and Solids

Abstract: UNLABELLED The aim of the present study was to develop a dual-carbon-labeled breath test for simultaneously measuring gastric emptying rates of liquids and solids with significantly less radiation burden to the patient than the radioscintigraphic technique. METHODS A test meal was used in which the liquid phase was labeled with two markers, i.e., 3.7 MBq of 111In-DTPA and 100 mg of 13C-glycine; the solid phase also was dually labeled with 110 MBq of 99mTc-albumin colloid and 74 kBq of 14C-octanoic acid. Simultaneous radioscintigraphic and breath-test measurements were performed in 27 subjects, 10 normal controls and 17 patients with dyspeptic symptoms. Mathematic analysis of the excretion rate of labeled CO2 allowed the definition of four parameters, i.e., the gastric emptying coefficient, the gastric half-emptying time, the peak excretion time and the lag phase. RESULTS There was a good to excellent correlation between the gastric emptying coefficient and the scintigraphic half-emptying time (r = 0.74 for liquids and r = 0.88 for solids), between the half-emptying time determined by breath test and the scintigraphic half-emptying time (r = 0.91 for liquids and r = 0.92 for solids), between the peak excretion time and the scintigraphic half-emptying time (r = 0.91 for liquids and r = 0.96 for solids) and between the lag phase of solid emptying determined by both techniques (r = 0.89). CONCLUSION The dual carbon-labeled breath test is a valid, minimally invasive technique to measure the gastric emptying rate of both liquids and solids.

Accelerated caffeine metabolism after omeprazole treatment is indicated by urinary metabolite ratios: coincidence with plasma clearance and breath test.

Abstract: Background Omeprazole has previously been shown to induce hepatic cytochrome P4501A2 activity, as evidenced by an accelerated N-3-demethylation in the 13C-[N-3-methyl]-caffeine breath test. In this study we investigated whether the inducing potency of omeprazole can be quantified by the determination of urinary caffeine metabolite ratios, which are based on the urinary excretion of N-3-demethylated metabolites. These data were also compared with changes in plasma clearance. Methods Twelve healthy volunteers were phenotyped as extensive metabolizers of S-mephenytoin and received seven daily doses of 40 mg omeprazole; eight of these were also treated with 120 mg/day. Moreover, six poor metabolizers were treated with 40 mg/day omeprazole. Three different urinary caffeine metabolite ratios were evaluated from urine samples collected between 5 and 8 hours after caffeine intake. Results The extensive metabolizers had a slight and nonsignificant acceleration between 7.8% and 17.0% after 40 mg omeprazole by the urinary ratios. However, treatment with 120 mg/day led to highly significant increases ranging from 25.0% to 32.1% (p < 0.002) in this group. Poor metabolizers responded with the highest increases of 40.2% to 41.2%. There was a good correlation between these parameters and the caffeine breath test, as well as the plasma caffeine clearance. Conclusion The study showed an equivalent caffeine N-3-demethylation activity by all evaluation methods. The three urinary caffeine metabolite ratios sampled at the convenient interval of 5 to 8 hours after administration showed the dependence of CYP1A2 induction by omeprazole on the dose and genetic trait of S-mephenytoin hydroxylase. Clinical Pharmacology and Therapeutics (1994) 55, 402–411; doi:10.1038/clpt.1994.49

Evolution of Helicobacter pylori positivity in infants born from positive mothers

Abstract: To evaluate the mother-child transmission of anti-Helicobacter pylori antibodies, we investigated 562 pregnant women by means of a commercially available second-generation enzyme-linked immunosorbent assay for the detection of anti-H. pylori IgG (Malakit Helicobacter pylori). One hundred twenty-eight of the 562 women had a positive serology for H. pylori. 13C-Urea breath tests were performed in 85 seropositive and in 65 randomly selected seronegative subjects. These breath tests were positive in 82 of the 85 (96.5%) seropositive and in none of the seronegative subjects, reflecting the actual presence of H. pylori in the gastric mucosa of the seropositive women. Cord blood levels for the Malakit Helicobacter pylori were positive in all infants born to seropositive mothers and negative in those born to seronegative mothers. In all infants the previously positive titers had turned negative by the age of 3 months. At the age of 12 to 15 months 13C-urea breath tests were performed in 67 infants born to seropositive mothers. These breath tests were positive in only one infant. By the time the 13C-urea breath tests were performed, the serology had turned negative in all infants with the exception of the one with the positive breath test. We conclude that the IgG antibodies against H. pylori cross the placental barrier and that, despite the present H. pylori infection in the mothers, infants born to these H. pylori-positive women do not appear to have an increased risk of developing a H. pylori-associated gastritis during the first year of life.

Pharmacological modulation of gastric emptying rate of solids as measured by the carbon labelled octanoic acid breath test: influence of erythromycin and propantheline.

Abstract: The *C (13C or 14C) labelled octanoic acid breath test was recently developed to measure the gastric emptying rate of solids. This study aimed to investigate whether it is sensitive enough to detect pharmacologically induced changes in the gastric emptying rate. Nine healthy volunteers were studied in basal condition, after intravenous administration of 200 mg erythromycin, and after peroral administration of 30 mg propantheline. Erythromycin significantly enhanced gastric emptying in all subjects, with an increase of the gastric emptying coefficient (p = 0.0043) in eight of nine and a fall in both the gastric half emptying time (p = 0.0020) and the lag phase (p = 0.0044) in all nine. Propantheline significantly reduced the gastric emptying rate, with a decreased gastric emptying coefficient (p = 0.0007) and an increased gastric half emptying time (p = 0.0168) in all subjects, but no change in the lag phase (p = 0.1214). Further mathematical analysis showed that breath sampling at 15 minutes intervals over a four hour period is recommended to guarantee accuracy and the discriminative value of the breath test in various gastric emptying patterns. In conclusion the *C labelled octanoic acid breath test is sufficiently sensitive to show pharmacologically induced changes of gastric emptying rates of solids.

More convenient 13C-urea breath test modifications still meet the criteria for valid diagnosis of Helicobacter pylori infection.

Abstract: AIMS AND METHODS 13C-Urea breath tests (UBT) were performed in 217 patients with epigastric symptoms to assess (a) the validity of shorter intervals of breath sample collection and (b) of the non-fasting state on diagnosing H. pylori infection and to evaluate (c) a more simple sampling method. (a) In 186 patients, breath samples were taken before and at 10, 20, 30, 40, 50, 60, 90, and 120 minutes after ingestion of 75 mg 13C-urea. 13C-enrichment was measured by isotope ratio mass spectrometry [delta/1000] and the cumulative recovery rate (CRR) was calculated. (b) 31 patients performed 13C-UBTs on two occasions, i.e. fasted and in the postprandial state collecting breath before and 30 min after substrate ingestion. (c) 61 breath samples were obtained in duplicate, i.e. both with an aluminium foil breath bag using evacuated glass tubes, and by exhalation into open vials via straw. RESULTS (a) DOB-responses at 10, 20, 30, and 40 minutes after dose showed a linear correlation with the 120 min-CRR. Referring to a CRR > 3% at 120 min (criterion of H. pylori-infection), DOB-responses at 20 min with a cut off-value at 5/1000 (ROC-analysis) were shown to be valid for diagnosing H. pylori status in man (sensitivity 99.0%, specificity 100%). (b) Postprandially, mean DOB-responses of H.pylori positive patients were lower than in the fasting state (17.46/1000 vs. 27.63/1000; p < 0.01). With the cut-off at 5/1000, however, sensitivity still was 94.4% and specificity was 100%. (c) The straw and breath bag method gave equivalent results (r = 0.98, p < 0.0001). CONCLUSIONS (a) A two sample measurement using the DOB at 20 min and a cut-off value of 5/1000 can replace the CRR-calculation over 120 minutes. (b) Although quantitative DOB-responses are significantly affected, 13C-UBT can be performed in the postprandial state with no significant effect on the detection of the H. pylori infection. (c) The sample collection by a simple straw method meets precision requirements < 1.5 delta/1000. Thus, the 13C-UBT can be performed cheaper, faster and more conveniently.

Gastric emptying of liquid meals measured noninvasively in humans with [13C]acetate breath test.

Abstract: The aim of the present study was to develop a breath test to measure liquid gastric emptying rates that would be without radiation exposure and applicable to field testing. Four different test meals were investigated: a glucose meal, an amino acid meal, a fat meal, and a mixed meal (Ensure). The test meals were labeled with two markers, [13C]acetate and PEG-4000 (polyethylene glycol 4000). Gastric emptying rates were measured simultaneously by both breath test and the double-indicator technique in eight healthy male subjects. The appearance of13CO2 in the breath closely reflected gastric emptying of the four test meals as measured by the double-indicator technique. It is concluded that the [13C]acetate breath test is a reliable, noninvasive test to measure gastric emptying rates of liquid test meals.

[*C]octanoic acid breath test to measure gastric emptying rate of solids.

Abstract: We have developed a breath test to measure solid gastric emptying using a standardized scrambled egg test meal (250 kcal) labeled with [14C]octanoic acid or [13C]octanoic acid. In vitro incubation studies showed that octanoic acid is a reliable marker of the solid phase. The breath test was validated in 36 subjects by simultaneous radioscintigraphic and breath test measurements. Nine healthy volunteers were studied after intravenous administration of 200 mg erythromycin and peroral administration of 30 mg propantheline, respectively. Erythromycin significantly enhanced gastric emptying, while propantheline significantly reduced gastric emptying rates. We conclude that the [*C]octanoic breath test is a promising and reliable test for measuring the gastric emptying rate of solids.

Clinically feasible stable isotope technique at a reasonable price: analysis of 13CO2/12CO2-abundance in breath samples with a new isotope selective-nondispersive infrared spectrometer.

Abstract: Up to now, stable isotope analysis of carbon dioxide in breath samples is carried out with sensitive but very expensive and complex isotope ratio mass spectrometry (IRMS) Aiming at a more widespread application of breath tests in gastroenterological diagnostic routine, we tested a newly developed isotope selective non-dispersive infrared spectrometer (NDIRS) in comparison to IRMS 13C-urea breath tests were performed in 63 patients as the routine screening method for Helicobacter pylori infection Breath samples at baseline and (15) 30 min after administration of the test solution containing 13C-urea were analysed both by NDIRS and conventional IRMS The correlation between the delta values of both devices was linear and in good agreement (r = 096; p < 00001; Y = 101 X -094) Comparing the delta over baseline-values, the correlation was Y = 111 X -036 (r = 098; p < 00001) Referring to the diagnosis of Helicobacter pylori infection with IRMS we calculated a sensitivity of 950% and an unchanged specificity (100%) for NDIR analysis In conclusion, NDIRS appears a promising, easy to operate, and low cost potential alternative to conventional IRMS thus encouraging further detailed investigation and more widespread application of the noninvasive stable isotope technique in breath tests for gastrointestinal function testing

Metabolism of cytochrome P4503A substrates in vivo administered by the same route: lack of correlation between alfentanil clearance and erythromycin breath test.

Abstract: Because there is considerable interindividual variation in both microsomal CYP3A4 activity and CYP3A4 substrate disposition, an established probe of in vivo CYP3A4 activity would represent an important advance in clinical practice. In a previous study, no correlation was found between the 14C-erythromycin breath test and urinary dapsone recovery ratio. However these drugs were administered by different routes, with the orally administered dapsone being exposed to presystemic metabolism by the gut and renal metabolism before the measurement of the urinary ratio. To overcome the variable of route of administration, the aim of this study was to determine whether the elimination of two intravenously administered CYP3A4 substrates (alfentanil and erythromycin) correlate. We compared the metabolism of alfentanil to its CYP3A4-dependent metabolite, noralfentanil, with the erythromycin breath test in 14 young healthy white men. No significant correlation was found between alfentanil metabolism and the erythromycin breath test: alfentanil clearance versus erythromycin breath test, r = 0.45, p = 0.1; partial metabolic clearance to noralfentanil versus erythromycin breath test, r = 0.35, p = 0.23. Because these two CYP3A4 substrates were administered by the same (intravenous) route, we conclude that differences in the route of administration do not explain the lack of correlation between the erythromycin breath test and other probes of CYP3A4 metabolism.

One week's anti-Helicobacter pylori treatment for duodenal ulcer.

Abstract: This open study tested whether eradication of Helicobacter pylori (H pylori) heals duodenal ulcers as well as decreasing recurrence. H pylori was detected in patients with endoscopic duodenal ulcers by histology, CLO-test, culture, and 13C-urea breath test (13C-UBT). Tripotassium dicitrato bismuthate (120 mg) and amoxycillin (500 mg) each four times daily, were given for seven days, with 400 mg metronidazole five times a day on days 5-7. The 13C-UBT was repeated immediately after treatment and endoscopy repeated within 21 days. After treatment unhealed ulcers were reinspected one month later and healed ulcers followed up by 13C-UBT alone for 12 months. Of 45 patients, 44 were available for follow up. Mean pretreatment excess delta 13CO2 excretion was 25.6 per mil, which fell to 2.4 per mil immediately after finishing treatment, indicating clearance of H pylori in every patient. At the second endoscopy (median interval 20 days from start of treatment) 33 of 44 (75%) duodenal ulcers had healed. Ten of the remaining 11 duodenal ulcers were smaller and those 10 healed in the next two weeks with no further treatment. Two patients' ulcers that initially healed with clearance of H pylori recurred three weeks later (both had metronidazole resistant H pylori). H pylori was eradicated in 28 of 44 (64%) patients (13C-UBT negative for median follow up 10.2 months). Overall 41 of 43 (93%, 95% confidence intervals 81%-99%) duodenal ulcers were healed at one month. This study suggests that one week of anti-H pylori triple treatment is effective in healing duodenal ulcers.

Mitochondrial Function Reflected by the Decarboxylation of [13C]Ketoisocaproate Is Impaired in Alcoholics

Abstract: Mitochondria of patients with alcoholic liver disease exhibit structural abnormalities, and mitochondria isolated from animals exposed to ethanol are functionally deficient when studied in vitro. To assess possible functional consequences of these ethanol-associated alterations in vivo, we measured mitochondrial function in alcoholics noninvasively with a breath test. A mitochondrial function, the decarboxylation of ketoisocaproate (KICA), was assessed by measuring the exhalation of 13CO2 following the administration of 1 mg/kg 2-keto[1-13C]isocaproic acid, the decarboxylation of which occurs in mitochondria. The results of the KICA breath test in 12 alcoholic subjects were compared with the results in healthy controls and patients with nonalcoholic liver disease. The peak exhalation of 13CO2 and the fraction of the administered dose decarboxylated in 120 min were both significantly lower in alcoholics than in healthy controls and patients with nonalcoholic liver disease. In alcoholics, KICA decarboxylation was impaired in the presence of normal quantitative liver function tests such as the aminopyrine breath test and galactose elimination capacity, indicating that KICA decarboxylation does not simply reflect a decreased functional hepatic mass. The enrichment of circulating KICA with [13C]KICA was similar in alcoholics and controls, indicating that a decreased bioavailability or an increased dilution of labeled KICA cannot account for the decreased exhalation of 13CO2 It is concluded that mitochondrial function as reflected by KICA decarboxylation is impaired in chronic alcoholics. The functional impairment is specific for ethanol abuse and not a reflection of decreased global hepatic function. KICA decarboxylation could thus be useful as a marker for excessive ethanol consumption.

Carbohydrate Malabsorption: Quantification by Methane and Hydrogen Breath Tests

Abstract: Rumessen JJ, Nordgaard-Andersen I, Gudmand-Hoyer E. Carbohydrate malabsorption: quantification by methane and hydrogen breath tests. Scand J Gastroenterol 1994;29:826-832.Background: Previous studies in small series of healthy adults have suggested that parallel measurement of hydrogen and methane resulting from gut fermentation may improve the precision of quantitative estimates of carbohydrate malabsorption. Systematic, controlled studies of the role of simultaneous hydrogen and methane measurements using end-expiratory breath test techniques are not available. Methods: We studied seven healthy, adult methane and hydrogen producers and seven methane non-producers by means of end-expiratory breath test techniques. Breath gas concentrations and gastrointestinal symptoms were recorded at intervals for 12 h after ingestion of 10,20, and 30 g lactulose. Results: In the seven methane producers the excretion pattern was highly variable; the integrated methane responses were disproportional and not reliably rep...

Dependence of the utilization of a phenylalanine-free amino acid mixture on different amounts of single dose ingested: A case report

Abstract: For patients with phenylketonuria the daily ingested phenylalanine-free amino acid mixture is the most important source of nitrogen. It is recommended to ingest one third of the total amount combined with main meals. Some patients, especially the older ones, do not follow this recommendation; they ingest the entire daily amount of amino acid mixture in one portion. This intake mode leads to an increased oxidative utilization of the amino acids. To set up an example for this metabolic phenomenon, a13C-leucine breath test was performed in one female phenylketonuric patient. She ingested a third of her daily amount of the amino acid mixture combined with an oral tracer of 3 mg13C-leucine/kg body weight at breakfast. The breath test was carried out by a standardized time schedule over 5 h. Three days later the breath test was repeated when she ingested the total amount of amino acid mixture in only one portion at breakfast. Total daily caloric intake and food composition were not changed. On both days a 24 h urine was collected to determine total nitrogen loss. The13C-content of expired air was analysed by gas isotope ratio mass spectrometry, the total nitrogen content was determined using a combustion unit. The13C-elimination rate as a percentage of the applied13C-tracer was 9.5% on the first test day as compared to 19.6% on the 2nd day. The corresponding total nitrogen excretion was increased (4.3–6.9 g/24 h). This single case study showed the expected results and confirmed the hypothesis that the ingestion of high amounts of amino acid mixtures is accompanied by a significantly increased oxidative utilization.

The lactulose hydrogen breath test as a measure of orocaecal transit time

Abstract: OBJECTIVE: To establish normal values and assess the reproducibility of the lactulose hydrogen breath test in measuring orocaecal transit time in control subjects, and to report results in a group of patients with chronic constipation as a result of colonic inertia. DESIGN: Open study. SETTING: Academic clinic. SUBJECTS: 42 Control subjects (29 women and 13 men) in 25 of whom the test was repeated within 2-4 weeks, and 19 patients. INTERVENTIONS: Lactulose hydrogen breath test. MAIN OUTCOME MEASURES: Sustained increase in hydrogen production of 3 ppm or more. RESULTS: Coefficient of variation within subjects was 8% compared with 38% between subjects; 3 of the control subjects (7%) and 3 of the patients (16%) did not ferment lactulose, the the incidence was similar in men (1/13, 8%) and women (2/29, 7%). Mean (SD) orocaecal transit time was significantly shorter among the 29 women (60 (27) minutes) than among the 11 men (89 (24) minutes) (p < 0.005). There were no significant differences between men in the control group and those with constipation. CONCLUSIONS: The lactulose hydrogen breath test is valuable to assess orocaecal transit time. It is simple, non-invasive, and reproducible, and may be of value in differentiating between generalised hypomotility and colonic inertia.

Lactulose hydrogen breath test in orocecal transit assessment. Critical evaluation by means of scintigraphic method.

Abstract: Orocecal transit time can be studied easily using the hydrogen breath test with lactulose, but the method has some important limitations. The orocecal transit time of 10 patients suffering from irritable bowel syndrome was measured twice, at a one-week interval, by breath test and scintigraphy simultaneously using an aqueous solution of 20 g lactulose containing 74 MBq of [99mTc]DTPA. Abdominal radioactivity and alveolar hydrogen values obtained every 5 min were noted and used to obtain the following: orocecal transit time by the two methods; ileocecal lactulose flow; total and per gram of lactulose hydrogen production; mean hydrogen concentration during the right colon filling; and measurement error of the breath test with respect to the scintigraphy. In the case of the breath test, the orocecal transit time intrapatient reproducibility was better (coefficient of variation =13.5%) when a hydrogen threshold increment of 5 ppm was used; the best correlation with the scintigraphic measurement was observed at this threshold (r=0.90,P<0.001). The breath test overestimated orocecal transit time with the error correlating negatively and significantly with the total hydrogen production and, particularly, the mean hydrogen concentration (r=0.79,P<0.01): for a mean hydrogen concentration of more than 15 ppm, the error was negligible, while within this value there was a noticeable overestimation. To conclude, the lactulose hydrogen breath test is capable of giving an accurate measurement of orocecal transit time if a hydrogen threshold increment of 5 ppm is chosen and if the mean hydrogen concentration in the first 30 min of the right colon filling is taken into account.

Helicobacter pylori in patients with systemic sclerosis : detection with the 13c-urea breath test and eradication

Abstract: In patients with systemic sclerosis peristaltic abnormalities may delay gastric emptying, giving rise to bacterial overgrowth, including possibly Helicobacter pylori (HP). Infection with Helicobacter is an important risk factor for esophageal and gastric diseases, including esophagitis, gastritis and gastric cancer. The purpose of this prospective study was to assess gastric HP infection in patients with systemic sclerosis. In 12 patients with systemic sclerosis the newly introduced breath test with 13C-labelled urea was used for indirect detection of gastric urease activity due to HP infection. Five out of 12 patients gave Helicobacter-positive results (42%); 7 patients were negative for Helicobacter colonization (58%). Thus, the risk for gastric diseases caused by HP infection is enhanced in patients with systemic sclerosis compared with white healthy, asymptomatic persons examined in other studies. Helicobacter-positive patients were treated with 2 x 20 mg omeprazole and 4 x 500 mg amoxicillin over 14 days. Afterwards the 13C-urea breath test was repeated and showed negative results for Helicobacter in all systemic sclerosis patients treated. Dual therapy with omeprazole and amoxicillin therapy effectively eradicated HP. The 13C-urea breath test did not cause any side-effects and is therefore considered to be a non-invasive, non-toxic and safe method for the diagnosis and therapeutic control of Helicobacter-status.

Inhibition of caffeine metabolism by ciprofloxacin in children with cystic fibrosis as measured by the caffeine breath test.

Abstract: The caffeine breath test was carried out in six children with cystic fibrosis, before and during a course of ciprofloxacin. There was a significant decrease in the 2 h cumulative labelled CO2 exhaled during ciprofloxacin treatment, mean difference (s.d.) -5.2(3.3)%, P < 0.02. The results suggest an inhibition of 3-N-demethylation of caffeine (CYP1A2 enzyme activity) by ciprofloxacin. Ciprofloxacin may cause significant drug interactions in children with cystic fibrosis. The caffeine breath test can be used to study drug interactions involving CYP1A2 in children.

Liver function breath test using aromatic amino acids

Abstract: A test for determining hepatic function has been developped. This test uses oral administration of isotope labeled phenylalanine or tyrosine, particularly 13C-phenylalanine, in a rapid breath test. In the preferred mode, the breath sample is analysed using a mass spectrometer and compared with a standard. The breath test provides a dynamic rather than static determination of hepatic function and can be used for both early and late stage liver problems.

Difficulty in eradicating Helicobacter pylori in a population at high risk for stomach cancer in Venezuela.

Abstract: The bacteriumHelicobacter pylori (HP) has been implicated in the etiology of precancerous lesions of the stomach and there is evidence suggesting that it may influence the efficacy of chemoprevention of gastric cancer with vitamin C. Eradication seldom has been attempted in populations from developing countries, with a high prevalence of HP frequently resistant to metronidazole. A randomized, double-blind, controlled trial to evaluate the efficacy of colloidal bismuth subcitrate (120 mg q.i.d.) and amoxycillin (500 mg q.i.d.) in eradicating HP was conducted in 220 subjects drawn from a population with a high prevalence of metronidazole-resistant HP in Tachira state, Venezuela. One month after completion of two weeks' treatment, eradication rates of 6.5 percent in the treatment group and two percent in the placebo group were estimated on the basis of HP diagnosis in biopsies, and of 13.9 percent compared with 3.9 percent on the basis of a14C-urea breath test, although the negative predictive value of the breath test was very low compared with HP diagnosis in biopsies. In the treatment group, particularly among males, a significant decrease in bacterial load was detected. Reasons for failure of treatment in high HP-prevalence areas are discussed, and it is suggested that primary prevention of HP infection may be the optimal approach to reducing levels of stomach cancer in these high-risk groups.

The aminopyrine breath test.

Abstract: The metabolic basis and clinical application of the aminopyrine breath test (ABT) as a measure of liver function is reviewed in this article. Several papers have been published in the 20 years that have elapsed since the test was validated in man by Hepner and Vesell. Nevertheless, even if the aminopyrine breath test has been shown to be a non-invasive, reliable and semiquantitative liver function test with diagnostic and prognostic accuracy, it is not yet extensively used in clinical practice, probably because it is not widely known to clinicians. The aminopyrine breath test, like other newer tests (phenacetin, caffeine and erythromycin breath tests), allows the effects of drugs on hepatic cytochrome P-450 to be explored both in normal subjects and in liver patients. This interesting field of application is sure to expand the appeal of the aminopyrine breath test in the future.