Evaluation of the lactulose/mannitol and 51Cr-ethylenediaminetetraacetic acid/14C-mannitol methods for intestinal permeability.

BACKGROUND: We earlier compared the lactulose/mannitol and 51Cr-ethylenediaminetetraacetic acid (EDTA)/14C-mannitol methods for intestinal permeability We have now investigated an increased number of control subjects, with special regard to the influence of urinary volume, sex, age, and smoking on marker excretion, and patients with intestinal disorders, with special regard to correlations between markers. METHODS: The 0- to 6-h urinary excretion of orally administered markers was measured in 65 control subjects and in 70 patients. RESULTS: In the control group excretion of mannitol and 14C-mannitol (small-pore permeability markers) was strongly correlated to urinary volume, whereas such correlation was weak for lactulose and absent for 51Cr-EDTA (large-pore permeability markers). No sex difference in marker excretion was found, but correlation to urinary volume was more pronounced in males. There was a slightly decreasing excretion of markers with increasing age, reaching significance for 51Cr-EDTA and 14C-mannitol; their excretion ratio was unaffected. Smoking did not significantly affect marker excretion. In the patient group the excretion of large-pore markers tended to be higher and that of small-pore markers to be lower than in the control group; correlation between the large-pore markers, between the small-pore markers, and between the large-pore/small-pore marker ratios was higher than in the control group. CONCLUSIONS: Correction for urinary volume substantially reduces variability in small-pore marker excretion. Excretion of both types of markers tends to decrease with age, the large-pore/small-pore marker ratio remaining unchanged. Smoking does not affect small-intestinal permeability. 14C-mannitol is preferred to chemically determined mannitol owing to lower test variability.

Faecal bile acid excretion during detoxification in patients with alcohol abuse.

BACKGROUND: We wanted to ascertain whether alcohol abuse is associated with a changed faecal bile acid excretion. METHODS: Faecal bile acid excretion was studied in seven chronic alcoholic subjects when admitted to hospital for detoxification. Bile acids in faeces and serum were quantified by gas-liquid chromatography and identified by mass spectrometry. RESULTS: Daily faecal bile acid excretion was on average 948 mumol in the patients at admission, compared with 400 mumol in eight healthy controls (P < 0.01). The daily faecal bile acid excretion decreased slowly during the detoxification period but was still higher in the patients than in controls after 9 days of detoxification (P < 0.05). Faecal bile acid excretion varied greatly between the different patients, with poor correlation to diarrhoea. In one patient the faecal bile acid excretion was remarkably high, amounting to an average of 6800 mumol day-1 during the first 3 days. The percentage metabolites of total faecal bile acids in the patients did not differ significantly from that of controls. The faecal wet weight was higher in the patients than in the controls, although significantly so only after the first 3 days of detoxification. CONCLUSIONS: Faecal bile acid excretion is increased after alcohol abuse. A gradual decrease in faecal bile acid excretion was observed during the 9-day observation period when the subjects abstained from alcohol.

Inhibition of the migrating motor complex by duodenal drainage in man.

The effect of varying bile acid output on fasting small intestinal motility was investigated in healthy male volunteers. Biliary output was manipulated by jejunal infusion of isotonic mannitol, which resulted in increased output, and by prolonged drainage of duodenal contents, which resulted in decreased output. Intestinal motility was measured by manometric recordings performed at four levels in the proximal small intestine. A marker dilution technique was used to measure pancreatico-biliary output. There were three experimental groups: duodenal drainage, non-drainage and control. Both duodenal drainage and non-drainage groups underwent jejunal saline infusion, followed by mannitol infusion. The control group did not receive drainage or infusions. In the drainage group, 0.41 (0.13-0.68) activity fronts of the migrating motor complex (MMC) per hour were recorded during saline infusion, but only 0.06 (0-0.19) activity fronts per hour were observed during mannitol infusion. In the non-drainage group, 0.71 (0.61-0.81) activity fronts per hour were observed during saline infusion and 0.50 (0.18-0.82) activity fronts per hour were recorded during mannitol infusion. In the control group, 0.58 (0.33-0.84) activity fronts per hour were recorded during the first 4-h session and 0.58 (0.45-0.71) activity fronts per hour during the second session. There was no difference between the number of activity fronts per hour observed in the control group and those observed in the saline infusion of the drainage group.(ABSTRACT TRUNCATED AT 250 WORDS)

Liver function tests and urinary albumin in house painters with previous heavy exposure to organic solvents.

The serum activities or concentrations of aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), alkaline phosphatase (ALP), albumin, gamma-glutamyl transpeptidase (GGT), bilirubin (BIL), cholic acid (CHOL), chenodeoxycholic acid (CHENO), and transferrin with isoelectric point 5.7, and the urinary excretion of albumin were determined among male current or former house painters (n = 135) and house carpenters (n = 71) who had worked in their trades for at least 10 years before 1970. Workers who showed a value above the 90th percentile among the carpenters in at least one of the tests ASAT, ALAT, GGT, BIL, CHOL, or CHENO were regarded as showing "possible signs of liver dysfunction". Each participant's lifetime solvent exposure was evaluated by interview. The painters were divided into categories with low, intermediate, and heavy cumulative exposure during life (LTSE) or during the most exposed year (MEYSE). All participants stated none or slight recent exposure. The prevalence of possible signs of liver dysfunction increased with solvent exposure category according to LTSE as well as MEYSE with a numerically higher risk estimate in the heavy exposure category for MEYSE than for LTSE. ALP activity increased with exposure category according to both exposure estimates. This increase seemed to be due to an interaction between exposure to solvents and current or previous long term intake of medicines potentially toxic to the liver. None of these results was affected by whether or not the subjects had been exposed to solvents during the year before the investigation. The exposure to solvents was not significantly related to any other outcome variable. It is concluded that long term heavy exposure to solvents may elicit changes in conventional liver function tests indicative of a mild chronic effect on the liver. The findings also suggest that heavy solvent exposure during short time periods is a more likely cause of the findings than lifetime cumulative solvent exposure and that an interaction between solvent exposure and medicines potentially harmful to the liver may be important in the causation of the effects.

Comparison between the lactulose/mannitol and 51Cr-ethylenediaminetetraacetic acid/14C-mannitol methods for intestinal permeability. Frequency distribution pattern and variability of markers and marker ratios in healthy subjects.

Urinary excretion of lactulose and mannitol, determined by gas-liquid chromatography, was compared with that of 51Cr-ethylenediaminetetraacetic acid (EDTA) and 14C-mannitol for measurement of intestinal permeability in 28 healthy humans. The 0- to 6-h excretion values for unlabelled and labelled mannitol (marker of transcellular permeability) were normally distributed, whereas excretion values for lactulose and 51Cr-EDTA (markers of paracellular permeability) were skewly distributed, as were the lactulose to mannitol and 51Cr-EDTA to 14C-mannitol ratios. Excretion of the transcellular markers but not of the paracellular markers was significantly correlated to urinary volume; correction for urinary volume resulted in decreased test variability. Significant correlation was found between lactulose and 51Cr-EDTA excretion (p < 0.01) and between mannitol and 14C-mannitol excretion (p < 0.001) but not between the lactulose to mannitol and 51Cr-EDTA to 14C-mannitol ratios (p = 0.11). Inter- and intraindividual test variability was greater for each chemically determined marker than for the corresponding isotope-labelled marker. Similarly, variability was greater for each paracellular marker than for the corresponding transcellular marker and for each paracellular/transcellular marker ratio than for the transcellular marker alone. Variability of mannitol excretion was increased by the frequent presence of food-derived mannitol in the urine.

Pancreaticobiliary juice releases motilin during phase I of the migrating motor complex in man.

The effect of duodenal perfusion with pancreaticobiliary juice on plasma motilin was investigated in eight fasting subjects. The study was undertaken with recording of gastrointestinal motility, to predict spontaneous fluctuations in plasma motilin levels. Duodenal perfusion with pancreaticobiliary juice or saline at a rate of 5 ml/min for 10 min was performed in random order after the second or third activity front. The 30-min integrated plasma motilin response was significantly greater after perfusion with pancreaticobiliary juice: 1.5 (0.7-2.3) nmol x min/l (mean and 95% confidence interval), compared with 1.0 (0.5-1.5) nmol x min/l after saline (p < 0.05). Although perfusion with pancreaticobiliary juice was followed by endogenous plasma motilin peaks after about 20 min in six of eight subjects, the mean interval to the next activity front was not significantly different. In conclusion, duodenal perfusion with pancreaticobiliary juice in phase I of the migrating motor complex releases plasma motilin without affecting the fasting motility pattern.

Long-term double-blind study on the influence of dietary fibres on faecal bile acid excretion in juvenile ulcerative colitis.

A double-blind cross-over long-term trial (18 months) with randomized supplementation with wheat fibre or ispaghula for two periods of six months, separated by a six-month wash-out period with placebo, was performed in ten patients with juvenile ulcerative colitis to study the effect on faecal bile acid (BA) excretion. All patients were in remission since 0.5-2 years and orally treated with sulphasalazine. The average intake of either fibres was 16 g day-1. Faecal samples were collected (72 h) before and after each fibre period. Faecal water were prepared by centrifugation of faeces at 15,000 g for 2 h. BA in faeces and faecal water were studied using capillary column gas-liquid chromatography-mass spectrometry. Faecal excretion of total BA were not significantly changed by the two fibres. Supplementation with wheat fibre, but not with ispaghula, decreased the faecal concentration of total BA by 43% (p < 0.05), unconjugated BA by 41% (p < 0.01), and taurine conjugated BA by 58% (p < 0.05). Addition of wheat fibre decreased the concentration of chenodeoxycholic acid by 66% (p < 0.05) and isomers of cholic acid by 51% (p < 0.05) in faeces. The mean faecal water concentration of taurine-conjugated BA decreased by 55% when wheat fibre was added (p < 0.05) and the concentration of isomers of deoxycholic acid increased by 39% when ispaghula was supplemented (p < 0.05). The ratio isomeric deoxycholic acid to deoxycholic acid in faecal water increased significantly when wheat fibre was added (p < 0.05). The percentage distribution of secondary and ketonic BA was not influenced by the dietary fibre supplementation. The concentration of BA in faeces and faecal water decreased only by wheat fibre, suggesting that it is superior in obtaining an affect on faecal BA concentration.

Serum concentrations and excretion of bile acids in cirrhosis.

Bile acid concentrations in serum, and urinary and faecal excretion of bile acids have been studied in ten patients with liver cirrhosis as a consequence of alcohol abuse. Eight of the patients were categorized as Child group A, whereas the remaining two patients comprised Child group C. Individual bile acids were isolated and identified by gas chromatography coupled to mass spectrometry. Total fasting serum bile acid concentrations were elevated in all patients, but not correlated to conventional tests of liver function. Eight of the patients had increased urinary excretion of bile acids. Faecal bile acid-excretion was highly variable between patients, and also between Child's group A and C patients. Total fasting serum bile acid concentrations were not correlated to either urinary, faecal, or total bile acid excretion (= synthesis of bile acids) or to the ratio between urinary and faecal excretion of bile acids. The daily synthesis of bile acids showed a large overlap between Child's group A and C patients. The percentage of chenodeoxycholic acid and its metabolites relative to total daily excretion of bile acids did not correlate, indicating that the synthesis pathways for the primary bile acids does not systematically change in relation to the rate of synthesis. We conclude that even in mild cirrhosis, serum bile acid concentrations are elevated. However, no consistent changes in synthesis of bile acids or synthesis pathways was observed in such patients.

Presence of bile acid metabolites in serum, urine, and faeces in cirrhosis.

Studies have been made of the presence of bile acid metabolites in ten patients with liver cirrhosis as a consequence of alcohol abuse. Eight of the patients were categorized as Child group A, indicating only mild impairment of liver function, whereas the remaining two patients comprised Child group C. A complex mixture of bile acids was isolated from serum, urine, and faeces, and 26 bile acids were identified by gas-liquid chromatography coupled to mass spectrometry. Identification was made of the primary bile acids, cholic (C) and chenodeoxycholic (CDC) acid, and metabolites of these bile acids converted through 7-dehydroxylation, keto-formation, 6-hydroxylation, 1 beta-hydroxylation, allo-formation or nor-formation. All of the bile acids have previously been described either in healthy humans or patients with hepatobiliary disease. With the exception of C, CDC, and deoxycholic acid, all of the bile acids were present only infrequently, and none of the bile acids was pathognomonic for liver cirrhosis. The proportion of metabolites of the primary bile acids C and CDC was similar to that previously reported in healthy humans, the lowest proportion being recorded in the Child group C patients. Repeated determinations of the metabolite pattern in two patients showed large variations, indicating that the bile acid metabolism varies from time to time. We conclude that in mild cirrhosis, no significant alterations in microbial or hepatic transformation of bile acids seem to occur.

Blood pressure reduction during hemodialysis correlates to intradialytic changes in plasma volume.

Blood pressure alterations during hemodialysis were related to changes in body fluid in 14 patients with chronic renal failure. Changes in plasma volume (PV) and extracellular volume (ECV) were calculated from determinations of fluid volumes before and after hemodialysis, using 125I-albumin and 51Cr EDTA respectively. Reduction in body water was estimated from body weight changes. Weight loss was 3.3 +/- 0.3 kg (range 1.8-6.0 kg). The relative reduction of fluid was greater in the ECV, 21.6 +/- 3.2%, compared to plasma volume, 6.9 +/- 1.8%. The reduction in systolic blood pressure was related to both absolute (r = 0.66, p less than 0.05) and relative PV reduction (r = 0.72, p less than 0.02). There was no correlation between blood pressure reduction and weight loss or ECV changes. Only minor alterations were found in diastolic blood pressure. Plasma volume maintenance relates to blood pressure changes. Plasma volume monitoring could be useful for improving intradialytic hemodynamic control.

Equilibration of labelled and endogenous bile acids in patients with liver cirrhosis after administration of (24-14C)cholic and chenodeoxycholic acids.

On separate occasions (24-14C)cholic acid and (24-14C)chenodeoxycholic acid were administered intravenously to patients with liver cirrhosis and the isotope excretion in urine and faeces monitored. Bile acids in serum, urine and faeces were extracted and separated into unconjugated bile acids, glycine- and taurine conjugates, glucuronides and sulphates. Individual bile acid conjugates were separated by high-performance liquid chromatography (HPLC) and the unconjugated bile acids were separated by gas-liquid chromatography (GLC) and identified by gas chromatography-mass spectrometry (GC-MS). Individual bile acid conjugates were quantified and their isotope contents determined. In serum, isotope contents declined rapidly during the first day, followed by a markedly slow rate of reduction. In accordance with this, the excretion of isotope from the patients was found to be very slow and the routes of bile acid excretion were changed, which resulted in an increased ratio of urine/faeces isotope excretion. Studies of the ratio of labelled to endogenous bile acid conjugates indicated that a continuous transformation of the labelled compounds occurred during the period of study. As judged from serum bile acids, conjugation to glycine- or taurine conjugates was rapid. The specific activities of labelled sulphate esters were consistently lower than for other conjugates during the 300-min observation period. During the first day, the urinary bile acids contained a high proportion of unconjugated labelled bile acids, which gradually disappeared. Labelled primary bile acids were slowly converted into microbial products, mainly 7-alpha dehydroxylated derivatives. The observed slow transformations resulted in a much delayed equilibration of labelled and endogenous bile acid derivatives, which invalidates isotope techniques for calculation of kinetic data of bile acid turnover. However, the observed very slow turnover of labelled bile acids in cirrhosis, owing to the persistent high rate of intestinal absorption and low capacity for urinary excretion, makes it possible for the intestinal flora to markedly change the composition of the bile acids in the pool. Studies of endogenous urinary and faecal bile acid excretion revealed the changed route of bile acid excretion with a high urinary/faeces ratio and the decreased synthesis of bile acids in cirrhosis.

Whole body impedance measurements reflect total body water changes. A study in hemodialysis patients.

Fluid volume changes during hemodialysis was monitored by continuous whole body impedance measurements. The fluid changes recorded using this method was compared to fluid volume changes measured in plasma water (PV) using 125I-albumin, and extracellular volume (ECV) using 51Cr-EDTA before and after treatment, and total body water (TBW) changes reflected by continuous bed scale monitoring. Changes in impedance correlated to TBW changes, r = 0.80, p less than 0.001, while correlations to changes in ECV and PV were: r = 0.57 and r = 0.55, respectively, p less than 0.05. Alterations in body fluid volumes recorded with whole body impedance is best correlated to total body water changes. The use of continuous whole body impedance monitoring has been shown to offer a simple non-invasive method for recording total body water changes during hemodialysis.

Excretion of [24-14C] glycochenodeoxycholate-3-sulphate in patients with liver cirrhosis.

[24-14C] glycochenodeoxycholate-3-sulphate (GCDC-3S) was given intravenously to seven patients with liver cirrhosis and the elimination of the isotope from blood and the isotope excretion in urine and faeces followed. The bile acid conjugates in serum and urine were separated by HPLC and the change in specific activity in isolated conjugates determined. [24-14C] GCDC-3S was rapidly eliminated either by urinary excretion or faecal excretion and the half-life of the labelled conjugates varied between 76-198 min. No deamination or desulphation of the isotope occurred prior to urinary excretion. Only small amounts of GCDC-3S excreted in bile were absorbed from the intestine, as no isotope was recovered in other bile acid conjugates in serum.

Transport of serum bile acids in patients with liver cirrhosis and hyperbilirubinaemia.

From 12 patients with liver cirrhosis and hyperbilirubinaemia, the different conjugates of bilirubin and bile acids in the serum were separated and determined. The serum of the patients contained varying amounts of unconjugated bilirubin, which was not correlated to total serum bilirubin. No correlation between bilirubin conjugates and different conjugates of bile acids could be found, indicating different elimination processes for these substances. To examine whether a changed plasma transport of bile acids, which may contribute to the different excretion pattern of bilirubin and bile acids, occurs in liver cirrhosis, the bile acids in the different serum lipoprotein fractions were determined in seven of the patients. It was found that 40% of serum bile acids were bound to serum lipoproteins, despite decreased serum lipoprotein levels. The degree of lipoprotein binding of bile acids was not correlated to total serum bile acid concentrations. Cholic acid conjugates were present to a higher extent in the lipoprotein fractions than those of chenodeoxycholic acid or of deoxycholic acid. Determination was made of the distribution of individual conjugates between different lipoproteins and it was found that most of the glycine conjugates were present in high density lipoprotein, whereas the main part of sulphates and taurine conjugates were present in low density lipoprotein. These results indicate that a higher fraction of bile acids in liver cirrhosis is transported by lipoproteins in plasma, which may be of importance for the hepatic elimination of bile acids in cases with this disease.

Bile constituents in ascitic fluid.

Bile acids and other bile constituents were determined in serum and ascites from eight patients with liver cirrhosis and in ascites secondary to malignancy in six patients. In cirrhotic ascites, total bile acid levels averaged 53% of the serum levels. A positive correlation was evident between ascites and serum levels for both cholic and chenodeoxycholic acid. For cholic acid, the ascites to serum ratio was higher in all patients compared with the corresponding ratio for chenodeoxycholic acid. The ascites to serum ratios for glycine, taurine and sulphate conjugates were similar, no tendency being shown by any of the conjugates to leak more easily into ascites. The high levels of bile acids in cirrhotic ascites suggests that the abdominal cavity harbours a fraction of the bile acid pool, which should be taken into account when studying bile acid turnover in liver cirrhosis. Bilirubin levels in cirrhotic ascites averaged 24% of the serum values. A positive correlation between ascites and serum levels for unconjugated bilirubin was recorded, whereas the occurrence of bilirubin conjugates in ascites was variable. Albumin levels in cirrhotic ascites were 25% of the serum levels. The ascites to serum ratios for other proteins such as IgG, IgA and IgM and also cholesterol and phospholipids were lower than that for albumin. In malignant ascites, a pattern different from that in liver cirrhosis was seen, low bile acid levels being found. No difference between bilirubin levels was observed, while albumin and cholesterol levels were higher in malignant ascites, with no overlap between the patient groups. These results indicate that the complex mechanisms of ascites formation result in variable levels of bile constituents in ascitic fluid, which are further dependent on the underlying disease.

Serum bilirubin subfractions in patients with alcohol abuse during detoxication.

Sera were obtained from 41 alcohol abusers consecutively admitted for detoxication. Blood samples were withdrawn on the second, fourth and seventh days of abstention. Initial bilirubin values were moderately elevated in 10 patients. Determination of the bilirubin subfractions by high performance liquid chromatography showed elevated values of unconjugated (alpha), monoconjugated (beta), diconjugated (gamma) and albumin-bound (delta) bilirubin, in 8, 15, 4 and 15 patients, respectively. During abstention, the total bilirubin value normalized rapidly, only three patients still had values above the upper reference limit after 7 days. In patients with initially elevated values of bilirubin subfractions, only a few had elevated beta and gamma levels on the seventh day, whereas delta levels decreased at a slower rate and remained virtually unchanged. On admission, 27 patients exhibited elevated levels of serum bile acids; these values decreased during abstention and after 7 days only six patients had slightly elevated values. Only five patients had initially elevated levels of alkaline phosphatase (ALP). These became normalized in all but two patients during abstention. The results suggest that mild cholestasis is common among alcohol-abusers without clinically evident liver disease and that these changes are reversible on abstention.

Lipoprotein-bound bile acids in serum from healthy men, postprandially and during fasting.

Individual bile acids were determined by gas-liquid chromatography in, very low density, low density and high density lipoprotein fractions obtained by sequential ultracentrifugation of serum from normal adults, both postprandially and during fasting. The lipoproteins were found to contain 22-34% of fasting serum bile acids. The observed postprandial increase in bile acids did not exhibit any shift in the ratio between lipoprotein bound- and non-lipoprotein-bound bile acids. Bile acids were present in all isolated lipoprotein fractions, high density lipoproteins containing the highest amounts. In the lipoprotein fraction, a higher percentage of cholate than of chenodeoxycholate was found.

Bile acids in serum, ultrafiltrate of serum and saliva from patients with cholestatic jaundice.

Individual bile acid conjugates in serum, the ultrafiltrate of serum and in saliva from patients with cholestatic jaundice were determined by gas-liquid chromatography. The bile acid concentration in the ultrafiltrate was 4-20% of that in serum and had also a different composition, with higher ratio of cholic to chenodeoxycholic acid. In saliva, the bile acid concentration was 1-8% of that in serum and the composition was different due to a higher proportion of unconjugated cholic acid. The results indicate that neither the bile acid concentration in the ultrafiltrate, nor that in saliva corresponds to the non-protein-bound bile acids in serum.

Bile acid transport by serum lipoproteins in patients with extrahepatic cholestasis.

Individual bile acid conjugates were determined by gas-liquid chromatography in very low density (VLDL), low density (LDL) and high density (HDL) lipoprotein fractions obtained by sequential ultracentrifugation of serum from cholestatic patients. In the lipoproteins were found 16-48% of the serum bile acids. In LDL, the amount found was twice that in VLDL and HDL together. More cholic than chenodeoxycholic acid was detected in the lipoproteins. The occurrence of bile acids in lipoproteins might be of importance for the transport of bile acids from blood to peripheral tissues during cholestasis.

Bile acid conjugates present in tissues during extrahepatic cholestasis.

Bile acid concentrations in the muscle, subcutaneous fat and skin of patients with extrahepatic cholestasis were compared to those in serum. High concentrations were found in most tissue samples. In tissues from patients administered [24-14C]chenodeoxycholic acid, the specific activity was lower than that in serum, indicating a storage of bile acids in these tissues. In some patients, higher concentrations of bile acids were found in tissue samples than in serum. This was mainly due to increased concentrations of cholic acid. Monohydroxy bile acids were not found in increased concentrations. Bile acids covalently bound to tissues were not detected.