Assessment of the (14C) aminopyrine breath test in liver disease.

Galizzi, J; Long, Richard; Billing, Barbara H.; Sherlock, Sheila

doi:10.1136/gut.19.1.40

Cited by 73 publications

(22 citation statements)

References 11 publications

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“…Introduction of the stable isotope 13C was a further advantage in its application to h u m a n metabolic studies. We could show that the ]3C-AP breath test in children above the age of 2 years yields the same results as in adults with the 14C or 13C-Ap breath test, when the different approaches to analyse breath data are considered (maximal production rate of 13CO2, 2 or 3 h, cumulative excretion of 13C in percent of the administered dose and evaluation of a single 2-h 13CO2 excretion measurement) [5,8,24,25].…”

Section: Discussionmentioning

confidence: 96%

“…The 14C-or 13C-aminopyrine breath test has been shown to provide reliable quantitative information about microsomal hepatocellular function [4,5,8,[11][12][13]. This test is based on the hypothesis that aminopyrine (AP) demethylation is the first and rate limiting step in AP biotransformation, and measurement of specifically labelled CO2 in expired breath therefore reflects N-demethylase activity (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Development of N-demethylase activity measured with the 13C-aminopyrine breath test

et al. 1982

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The 13C-aminopyrine (AP) breath test was used to measure the normal development of N-demethylase activity in 25 children, aged 2 days to 14 years, with normal liver function. Five mg of 13C-AP per kg body weight were administered orally. After AP-demethylation by the hepatic mixed function oxidase system 13CO2 excess was analysed in expired breath by mass spectrometry. In the first days of life no 13C excretion could be detected in unstimulated newborns. N-demethylase activity then slowly increased and reached adult levels by two years of life. Though the range of normal values showed considerable scattering, patients with liver disease or with enzyme induction following anticonvulsant therapy could be well discriminated. This study of the 13C-aminopyrine breath test in children provides evidence for the assumption that hepatocellular function and development of specific enzymatic activities can be measured by such non-invasive methods. It may be expected that breath tests making use of a broader spectrum of 13C-labeled substrates will prove applicable to study prenatal inducibility and other aspects of developing hepatocellular and intestinal function of children in health and disease.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Development of N-demethylase activity measured with the 13C-aminopyrine breath test

et al. 1982

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“…4, No. 5,1984 UREA SYNTHESIS 907 determinations were done in quadruplicate with appropriate controls and blanks.…”

Section: Urea Synthesis Measurementsmentioning

confidence: 99%

Urea Synthesis After Protein Feeding Reflects Hepatic Mass in Rats† ‡

et al. 1984

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Urea synthesis is an exclusive biosynthetic function of the liver. Since the exact relationship between urea synthesis in vivo and functional liver mass remains unclear, we established an animal model using oral protein loading and measurement of resultant urea synthesis in rats. We studied rats subjected to sham operation, 40% hepatectomy, 66% hepatectomy, portacaval shunt and CCl4-induced cirrhosis. Urea synthesis was calculated as the sum of urinary urea excretion and accumulation of urea in body water during the 6-hr period after oral administration of a casein protein load equivalent to 20 gm per kg body weight. Peak urea synthesis rate in the sham-operated group of rats was 142 +/- 11 mumoles per hr per gm wet liver weight (mean +/- 1 S.D.), 473 +/- 34 mumoles per hr per gm liver protein and 80 +/- 5 mumoles per hr per mg liver DNA. This rate closely matched those of the other groups for each type of liver mass measurement. Marked reduction (p less than 0.01) of urea synthesis on a DNA basis was noted only in the CCl4-cirrhotic livers, related to the significantly higher (p less than 0.01) DNA content of the cirrhotic livers. Similarly, increased (p less than 0.05) liver protein content of the sham-operated rats when compared with the other groups was reflected in slightly lower urea synthesis rates expressed on the basis of liver protein (p less than 0.05) when compared to that of all other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Aminopyrine is rapidly and completely absorbed from the small bowel and is then homogeneously distributed in the total body water. Microsomal demethylation, predominant in the liver, accounts for at least 50-60% of its metabolism, so that measurement of the expired 13 CO 2 after an oral dose of 13 C 2 -aminopyrine accurately reflects the liver functioning mass [14].…”

Section: Introductionmentioning

confidence: 99%