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Composition and concentration of bile acid reflux into the esophagus of patients with gastroesophageal reflux disease.

BACKGROUND: Reflux of duodenal contents into the esophagus of patients with gastroesophageal reflux disease has been suggested by pH and bilirubin monitoring but is rarely directly measured. A portable device has been developed and was used to collect and quantitate material refluxed into the esophagus under ambulatory conditions during a prolonged time period. The objective of this study was to use this device to quantitate the composition and concentration of bile acids refluxed into the esophagus of patients with gastroesophageal reflux disease. METHODS: Esophageal aspiration was performed on 43 normal subjects and 37 patients with reflux disease during a 17-hour period. Aspiration was performed through a modified 16F Salem sump tube, positioned 5 cm above the lower esophageal sphincter and connected to a portable, battery powered pump that aspirated continuously at 100 mm Hg pressure. Validation studies showed that minimal amounts of saliva and swallowed liquids were aspirated and that gastric pressure was not altered. Postprandial, upright, and supine collections were performed. Total bile acids were assayed by a standard enzymatic assay; specific conjugated bile acids were analyzed by high-performance liquid chromatography. RESULTS: There was no difference in the total aspiration volume between normal volunteers and patients with gastroesophageal reflux disease, although patients tended to have a higher volume in the supine and postprandial periods. Bile acids could be detected in 58% of normal subjects and 86% of patients (p < 0.003). The mean concentration of bile salt exposure (micromole per liter) was higher in patients during the postprandial and supine periods. The mean bile acid reflux rate (micromole per hour) during all three aspiration periods was significantly higher in patients. On a molar basis the composition of the bile acids was 60% glycocholic acid, 16% glycodeoxycholic acid, and 15% glycochenodeoxycholic acid. Taurocholic, taurodeoxycholic, taurochenodeoxycholic, and glycolithocholic acid constituted the remaining 10%. CONCLUSIONS: Patients with reflux disease have an increased concentration of bile acids in their esophageal aspirates. Most of the exposure occurs during the postprandial and supine periods. A variety of bile acids were detected, most of which were in their glycine conjugated form.

Adult↗

Comparison of the binding of various bile acids and bile salts in vitro by several types of fiber.

The binding in vitro of the sodium salts of cholic acid, chenodeoxycholic acid, deoxycholic acid, taurocholic acid, taurochenodeoxycholic acid, taurodeoxycholic acid, glycocholic acid, glycochenodeoxycholic acid, and glycodeoxycholic acid by alfalfa, bran, cellulose, lignin, and cholestyramine was measured. Cholestyramine bound an average of 81.3% of all the bile acids and salts tested whereas cellulose bound only negligible amounts (1.4%). Of the other substances tested, lignin bound 29.2%, alfalfa, 15.9% and bran, 9.0%. No distinct pattern of binding was discerned. It is therefore apparent that the validity of statements concerning the effect of fiber on bile salf metabolism rests upon the specificity of the composition of the fiber involved and the bile acids or salts tested.

Bile Acids and Salts↗

Prevention of gallstone formation in rabbits by the oral administration of kanamycin.

Rabbits fed a diet containing 40 per cent casein, 15 per cent oleic acid and 45 per cent laboratory pellets developed glycoallodeoxycholic acid and glycodeoxycholic acid gallstones. The oral administration of kanamycin prevented allo bile acid stone formation in the oleic acid fed rabbit without leading to cholesterol gallstone formation. Kanamycin reduced the concentration of allodeoxycholic acid in the bile of oleic acid fed rabbits from 16.6+/-4.1 per cent of total bile acids to 1.1+/-1.1 per cent, with a reciprocal increase in deoxycholic acid concentration. The allodeoxycholate concentration was far below that found in control bile samples, 10.2+/-2.3 per cent. If the effect of kanamycin on the bile composition is by its antibiotic action, this eliminates the importance of a hepatic contribution to allodeoxycholate stone formation.

Administration, Oral↗

Comparison of the effects of bile acids on cell viability and DNA synthesis by rat hepatocytes in primary culture.

Bile acid-induced inhibition of DNA synthesis by the regenerating rat liver in the absence of other manifestation of impairment in liver cell viability has been reported. Because in experiments carried out on in vivo models bile acids are rapidly taken up and secreted into bile, it is difficult to establish steady concentrations to which the hepatocytes are exposed. Thus, in this work, a dose-response study was carried out to investigate the in vitro cytotoxic effect of major unconjugated and tauro- (T) or glyco- (G) conjugated bile acids and to compare this as regards their ability to inhibit DNA synthesis. Viability of hepatocytes in primary culture was measured by Neutral red uptake and formazan formation after 6 h exposure of cells to bile acids. The rate of DNA synthesis was determined by radiolabeled thymidine incorporation into DNA. Incubation of hepatocytes with different bile acid species - cholic acid (CA), deoxycholic acid (DCA), chenodeoxycholic acid (CDCA) and ursodeoxycholic acid (UDCA), in the range of 10-1000 microM - revealed that toxicity was stronger for the unconjugated forms of CDCA and DCA than for CA and UDCA. Conjugation markedly reduced the effects of bile acids on cell viability. By contrast, the ability to inhibit radiolabeled thymidine incorporation into DNA was only slightly lower for taurodeoxycholic acid (TDCA) and glycodeoxycholic acid (GDCA) than for DCA. When the effect of these bile acids on DNA synthesis and cell viability was compared, a clear dissociation was observed. Radiolabeled thymidine incorporation into DNA was significantly decreased (-50%) at TDCA concentrations at which cell viability was not affected. Lack of a cause-effect relationship between both processes was further supported by the fact that well-known hepatoprotective compounds, such as tauroursodeoxycholic acid (TUDCA) and S-adenosylmethionine (SAMe) failed to prevent the effect of bile acids on DNA synthesis. In summary, our results indicate that bile acid-induced reduction of DNA synthesis does not require previous decreases in hepatocyte viability. This suggests the existence of a high sensitivity to bile acids of cellular mechanisms that may affect the rate of DNA repair and/or proliferation, which is of particular interest regarding the role of bile acids in the etiology of certain types of cancer.

Animals↗

Dietary inulin lowers plasma cholesterol and triacylglycerol and alters biliary bile acid profile in hamsters.

The mechanisms by which inulin may elicit its lipid-lowering effect are not well elucidated. To examine the lipid-lowering potential of inulin and especially its effect on bile acid metabolism, male golden Syrian hamsters were fed semipurified diets containing 20 g/100 g fat, 0.12 g/100 g cholesterol and 0 (control), 8, 12 or 16% inulin for 5 wk. Plasma total cholesterol concentrations were significantly lowered by 18, 15 and 29% in hamsters fed 8, 12 and 16% inulin, respectively. Dietary inulin specifically decreased VLDL cholesterol, which was significantly lower in hamsters fed 16% inulin compared with controls (1.1 +/- 0.3 vs. 2.9 +/- 0.6 mmol/L). LDL and HDL cholesterol were not significantly affected by dietary inulin. Plasma triacylglycerol was significantly reduced by 40 and 63% in hamsters fed 12 and 16% inulin, respectively. Hepatic total cholesterol and particularly esterified cholesterol accumulation were significantly lower in hamsters fed 8% inulin compared with controls. All three levels of dietary inulin caused distinct alterations in the bile acid profile of gallbladder bile. Taurochenodeoxycholic acid was significantly lower, whereas glycocholic and glycodeoxycholic acid were greater in hamsters fed inulin. Daily fecal bile acid excretion (micromol/d) tended to be greater (P = 0.056) in inulin-fed hamsters compared with controls, whereas daily neutral sterol excretion was not affected. These data demonstrate that the lipid-lowering action of inulin is possibly due to several mechanisms, including altered hepatic triacylglycerol synthesis and VLDL secretion and impaired reabsorption of circulating bile acids.

Animals↗

Effect of epidermal growth factor on growth and postnatal development of the rabbit liver.

The effect of epidermal growth factor (EGF) on the postnatal development of the liver was examined. New Zealand White rabbits received 40 micrograms.kg-1.day-1 EGF from days 3 to 17 of age either intraperitoneally or orogastrically, whereas controls received saline. At days 18-20, animals underwent cannulation of the common duct using halothane anesthetic. Biliary output was measured directly for three 1-h periods: under basal conditions and in response to intravenous infusion of exogenous glycodeoxycholic acid at 0.75 and 1.5 mumol.min-1.kg-1, respectively. The bile salt pool size was measured by isotope dilution. Final mean body weight of intraperitoneal and orogastric groups did not differ from controls. Liver we weight, DNA, and protein content were significantly increased in intraperitoneally treated animals without morphological or biochemical evidence of fat deposition. Both intraperitoneal and orogastric EGF significantly increased bile salt secretion in the basal period and as a response to exogenous bile acid infusion. Bile flow was significantly increased in response to 1.5 mumol.min-1.kg-1 infusion of glycodeoxycholic acid. The bile salt pool was increased by both intraperitoneal and orogastric EGF. Administration of EGF resulted in a precocious development of glucokinase (EC 2.7.1.2) activity in the liver. EGF had no effect on serum cortisol, corticosterone, triiodothyronine, thyroxine, or free thyroxine levels. These findings suggest that in the neonatal period EGF can promote hepatic growth and maturation.

Animals↗

Effects of dual inhibitor of cyclooxygenase and 5-lipoxygenase on acute necrotizing pancreatitis in rats.

BACKGROUND/AIMS: The aim of this study was to investigate the influence of dual inhibitor of cyclooxygenase and 5-lipoxygenase (ER-34122) on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. METHODOLOGY: ANP was induced in 96 rats by standardized intraductal glycodeoxycholic acid infusion and intravenous cerulein infusion. Rats were divided into six groups (6 rats in each group): Sham + saline, sham + ER-34122, which was dissolved in hydroxypropylmetylcellulose (TC-5RW), sham + TC-5RW, ANP + saline, ANP + ER-34122 and ANP + TC-5RW. Six hours after ANP induction ER-34122 (30 mg/kg), saline or TC-5RW was given by feeding tube. At the 12th hour, routine cardio-respirator, renal parameters were monitored to assess organ function. Serum amylase, alanine amino transferase (ALT), interleukin 6 (IL-6), lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid, serum concentration of urea, tissue activity of myeloperoxidase (MPO) and malondialdehyde (MDA) in pancreas and lung were measured. Pancreas histology was examined. In the second part of the study 60 rats were studied in four groups similar to first part. Survival of all rats was monitored for 24 hours. RESULTS: The induction of ANP resulted in significant increase in mortality rate, pancreatic necrosis and serum activity of amylase, ALT, IL-6, LDH in BAL fluid, serum concentration of urea, tissue activity of MPO and MDA in pancreas and lung, and significant decrease of serum concentrations of calcium, blood pressure, urine output and pO2. NAC did not change serum activity of amylase. The use of ER-34122 inhibited the changes in blood pressure, pO2, serum activity of ALT, pancreatic MPO and MDA levels, partially urine output, LDH level in BAL fluid and pancreatic damage. But ER-34122 could not effect the changes, such as serum activity of amylase, IL-6, serum concentration of urea and calcium, MPO and MDA levels in lung and the mortality rate. CONCLUSIONS: The use of ER-34122 has a limited value on the course of ANP. It has no role in the treatment of ANP.

Animals↗

Feedback regulation of bile acid synthesis in primary human hepatocytes: evidence that CDCA is the strongest inhibitor.

Primary human hepatocytes were used to elucidate the effect of individual bile acids on bile acid formation in human liver. Hepatocytes were treated with free as well as glycine-conjugated bile acids. Bile acid formation and messenger RNA (mRNA) levels of key enzymes and the nuclear receptor short heterodimer partner (SHP) were measured after 24 hours. Glycochenodeoxycholic acid (GCDCA; 100 micromol/L) significantly decreased formation of cholic acid (CA) to 44% +/- 4% of controls and glycodeoxycholic acid (GDCA) decreased formation of CA to 67% +/- 11% of controls. Glycoursodeoxycholic acid (GUDCA; 100 micromol/L) had no effect. GDCA or glycocholic acid (GCA) had no significant effect on chenodeoxycholic acid (CDCA) synthesis. Free bile acids had a similar effect as glycine-conjugated bile acids. Addition of GCDCA, GDCA, and GCA (100 micromol/L) markedly decreased cholesterol 7alpha-hydroxylase (CYP7A1) mRNA levels to 2% +/- 1%, 2% +/- 1%, and 29% +/- 11% of controls, respectively, whereas GUDCA had no effect. Addition of GDCA and GCDCA (100 micromol/L) significantly decreased sterol 12alpha-hydroxylase (CYP8B1) mRNA levels to 48% +/- 5% and 61% +/- 4% of controls, respectively, whereas GCA and GUDCA had no effect. Addition of GCDCA and GDCA (100 micromol/L) significantly decreased sterol 27-hydroxylase (CYP27A1) mRNA levels to 59% +/- 3% and 60% +/- 7% of controls, respectively, whereas GUDCA and GCA had no significant effect. Addition of both GCDCA and GDCA markedly increased the mRNA levels of SHP to 298% +/- 43% and 273% +/- 30% of controls, respectively. In conclusion, glycine-conjugated and free bile acids suppress bile acid synthesis and mRNA levels of CYP7A1 in the order CDCA > DCA > CA > UDCA. mRNA levels of CYP8B1 and CYP27A1 are suppressed to a much lower degree than CYP7A1.

Adult↗

The influence of bile salts and mixed micelles on the pharmacokinetics of quinine in rabbits.

The bioavailability of orally administered drugs can be influenced by interactions with food components and by physico-chemical conditions in the upper gastrointestinal tract. Normally, bile salts enhance the transport of lipophilic drugs across mucosal membranes. Bile salts are able to form stable mixed micelles consisting of fatty acids and phospholipids. Conventional micellar systems are known to solubilize lipophilic drugs having a low bioavailability. The influence of bile salts and mixed micelles on the pharmacokinetics of the lipophilic drug quinine was investigated in rabbits. Female rabbits were given intraduadenally quinine (5 mg/kg body weight) without and with incorporation into the micellar or mixed micellar systems. Blood was collected every 30 min for 6 h. In plasma, concentration of quinine was measured using HPLC. The plasma concentration-time profiles of quinine were significantly lower within the first 2 h after administration in presence of both the sodium salt of glycodeoxycholic acid (above the critical micellar concentration) as well as of mixed micellar systems consisting of glycodeoxycholic acid and palmitic acid and/or lecithin. The pharmacokinetic parameters AUC (relative bioavailability) and c(max) of quinine were significantly decreased by micellar systems in rabbits. These mixed micellar systems lower and not as expected, increase the absorption of quinine in vivo. Therefore, quinine should be orally administered at least 1h before food intake, particularly before fat intake.

Animals↗

Effects of octreotide on acute pancreatitis of varying severity in rats.

OBJECTIVE: To find out the effects of the octreotide on the course of acute pancreatitis in rats. DESIGN: Prospective laboratory study. SETTING: Medical school, Turkey ANIMALS: 184 Sprague-Dawley rats, 120 of which were randomly allocated into 8 groups of 15 each for the survival study, and the remainder of which were randomly allocated into 8 groups of 8 rats each for assessment of biochemical variables and histological score. INTERVENTIONS: The same 8 groups were used for the two parts of the study: saline alone (control), octreotide alone (control), oedematous pancreatitis induced by cerulein with and without octreotide, moderate pancreatitis induced by low-dose glycodeoxycholic acid and cerulein with and without octreotide, and severe pancreatitis induced by high-dose glycodeoxycholic acid and cerulein with and without octreotide. MAIN OUTCOME MEASURES: Mortality, results of biochemical tests, and histological score. RESULTS: No rats in the control groups died. Of those with oedematous pancreatitis 1 died that had not been given octreotide (7%) and 2 that had (13%). In the moderate pancreatitis groups 4 that had not been given octreotide died (27%) compared with one that had (7%). In the severe pancreatitis group 7 that had not had octreotide died (46%) compared with 6 that had (40%). Octreotide caused a reduction in serum amylase and lactate dehydrogenase activity in all groups, but reduced aspartate aminotransferase only in those rats with moderate pancreatitis. It prevented hypocalcaemia in rats with severe pancreatitis, but had no effect on serum electrolyte concentrations, alkaline phosphatase activity, or blood gas analyses. Rats with moderate pancreatitis that had been given octreotide had less tissue oedema, acinar necrosis, and inflammatory cell infiltration. In those with severe pancreatitis there was less tissue oedema but more acinar necrosis. CONCLUSION: If octreotide is given early in the course of the disease it may result in improved outcome, but it seems to be ineffective in severe pancreatitis in which acinar necrosis is already established.

Acute Disease↗

Combined use of Lactobacillus reuteri and soygerm powder as food supplement.

AIMS: The survival of Lactobacillus reuteri when challenged with glycodeoxycholic acid (GDCA), deoxycholic acid (DCA) and soygerm powder was investigated. Moreover, the impact of Lact. reuteri on the bioavailability of isoflavones present in soygerm powder was examined. METHODS AND RESULTS: The strain experienced a die-off when adding 2 or 3 mmol l-1 bile salts, with more pronounced effects in the case of DCA. By means of a haemolysis test it was shown that toxicity could be due to membrane damage. When 4 g l-1 soygerm powder was added, the Lactobacillus strain survived the bile salt burden better (P < or = 0.05) and the membrane damage in the haemolysis test decreased (P < or = 0.05). The Lact. strain cleaved beta-glycosidic isoflavones during fermentation of milk supplemented with soygerm powder. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: The interactions between the Lactobacillus strain and soygerm powder suggest that combining both in fermented milk can exhibit advantageous probiotic effects. The relevance of the combination of the strain and the soygerm powder should be studied under more relevant physiological conditions.

Animals↗

Evaluation and optimisation of separation buffers for the determination of corticosteroids with micellar electrokinetic capillary chromatography (MECC).

Separation buffers for the determination of the corticosteroids cortisone, hydrocortisone, prednisone and prednisolone with micellar electrokinetic chromatography were developed with respect to separation efficacy and the migration times, depending on the type and the concentration of the organic modifier acetonitrile as well as on the addition of gamma-cyclodextrin. The buffer containing 50 mM SDS and 16% (v/v) acetonitrile enables the rapid profiling of prednisolone together with cortisone and prednisone. Addition of gamma-cyclodextrin alters the elution sequence, but does not further enhance resolution of the corticosteroids. Baseline separation at long migration times for cortisone, hydrocortisone, prednisone and prednisolone is achieved with a buffer containing 50 mM each of SDS, dehydrocholic acid sodium salt and glycodeoxycholic acid sodium salt.

Acetonitriles↗

Effect of tamoxifen and raloxifene on cholesterol transformation to bile acids in ovariectomized rats.

Tamoxifen is used as adjuvant therapy for prevention and treatment of metastatic breast cancer, whereas raloxifene is approved for osteoporosis and is being investigated for breast cancer prevention. The most important aspects of these therapies are focused on their influence on bone and lipid metabolism. Several studies have reported the effect of tamoxifen and raloxifene on plasma lipids. Approximately 40% of total cholesterol removal occurs by conversion to bile acids, a process that takes place in the liver. The aim of the present study was to evaluate the influence of tamoxifen and raloxifene on the conversion of cholesterol to bile acids in estrogen-deficient in rats. The study included 40 female Wistar rats, divided into four groups: sham-operated controls, ovariectomized controls, ovariectomized rats treated with tamoxifen and ovariectomized rats treated with raloxifene. After 42 days of drug administration, bile was collected under anesthesia following administration of radioactive [4-(14)C]cholesterol and assayed for total (14)C radioactivity; (14)C-labeled bile acids were determined by the use of isotopic techniques after initial separation by thin-layer chromatography. Ovariectomy caused decreased excretion of bile and bile acids. Administration of tamoxifen and raloxifene significantly reduced the excretion of (14)C-labeled bile and bile acids compared with ovariectomized controls. Tamoxifen therapy significantly reduced the excretion of taurocholic acid and glycochenodeoxycholic plus glycodeoxycholic acids, and excretion of cholic, litocholic and chenodeoxycholic plus deoxycholic acids was increased. Raloxifene significantly reduced the excretion of taurocholic, glycocholic and litocholic acids, taurochenodeoxycholic plus taurodeoxycholic acids, as well as chenodeoxycholic plus deoxycholic acids. The results of the present study suggest that tamoxifen and raloxifene did not reverse the changes in bile composition induced by estrogen deficiency. The decreased concentration of trihydroxy bile acids during therapy with raloxifene might decrease the risk of gallstone formation, although this hypothesis requires further investigation.

Animals↗

Pulmonary injury in acute experimental pancreatitis correlates with elevated levels of free fatty acids in rats.

Since some authors have stated a certain role for so-called "free fatty acids" (FFA) in the pathogenesis of AP and the subsequent systemic complications we tried to find possible correlations between FFA, pancreatitis and lung injury using a rat model. AP was induced by intraductal infusion of two different concentrations of glycodeoxycholic acid (GDOC 17 mmol and 34 mmol). An equal number of animals had only cannulation of the pancreatic duct without infusion and served as controls (GDOC-control). In another experimental model iv.-infusion of oleic acid (OA) was used to create severe lung injury comparable to human ARDS. In this model control animals received iv.-infusion of saline solution only (SAL). At 2, 6, 12, 24 and 48 hours the animals were sacrificed and blood was collected for determination of FFA, amylase and pO2. The pancreas and lungs were removed for histologic examination and the lungs were weighed. GDOC-34 animals developed severe pancreatitis with hemorrhage and necrosis. Histology of the lungs showed edema, inflammatory infiltrates, hemorrhage and thickening of the alveolar membrane in GDOC-34 rats as well as in OA-animals. In contrast, there was only pancreatic edema until 24 hours in the GDOC 17 group and less severe histological changes in the lungs. Amylase, FFA, pO2 and lung weight were directly influenced by the different kinds of treatment. Furthermore, FFA correlated positively with the levels of amylase and lung weight and negatively with pO2. Infusion of OA alone also caused an increase in levels of amylase with pancreatic edema and focal necroses in some animals. These results show that it was possible to create different degrees of severity of AP which was in concordance with different degrees of morphologic changes and dysfunction in the lungs. FFA values correlated significantly with the clinical course as well as with increasing amylase, lung weight and decreasing pO2.

Acute Disease↗

Hypocalcemia in experimental pancreatitis occurs independently of changes in serum nonesterified fatty acid levels.

Hypocalcemia and lipid abnormalities commonly occur in acute pancreatitis. Experimentally, increased plasma concentrations of free fatty acids (NEFA) can lower the serum calcium (Ca). We hypothesized that changes in blood-ionized calcium might parallel changes in NEFA concentration in pancreatitis. This hypothesis was tested in a model of severe necrotizing pancreatitis and a model of mild edematous pancreatitis. Adult male Sprague-Dawley rats (300-400 g) were randomized to receive: 100 microL sodium glycodeoxycholic acid (GDOC 34 mmol/L) infused into the pancreatic duct to produce severe necrotizing pancreatitis (Group 1); 100 microL 0.9% NaCl (NS) infused into the pancreatic duct (Group 2); Sham laparotomy (Group 3); A 6 h IV infusion of cerulein (5 mucg/kg/h) to produce mild edematous pancreatitis (Group 4); and a 6 h IV infusion of NS (Group 5). A significant time dependent decrease in blood-ionized Ca concentration, compared to normal rats, was observed in both GDOC-pancreatitis (0.836 +/- .057 vs 1.069 +/- .038 mmol/L p less than 0.001) and cerulein pancreatitis (0.988 +/- .028 vs 1.069 +/- .038 p less than 0.05), which was maximal 24 h after induction of pancreatitis. The degree of hypocalcemia correlated with the severity of pancreatitis (GDOC 0.836 +/- .057 vs cerulein 0.988 +/- .028 p less than .001). Hypocalcemia was not observed in any of the control groups. All experimental and control groups had significantly increased baseline NEFA concentrations compared with normal rats (p less than 0.001); however, no further increase in NEFA concentration occurred in conjunction with the observed time-dependent decline in ionized calcium concentrations. Although the NEFA concentrations observed in these experiments were comparable to those measured in human acute pancreatitis (exclusive of hyperlipemic pancreatitis), the time course of the changes suggests that increases in serum NEFA concentrations in experimental pancreatitis are not the primary factor mediating hypocalcemia.

Acute Disease↗

A better model of acute pancreatitis for evaluating therapy.

Existing models of acute pancreatitis have limitations to studying novel therapy. Whereas some produce mild self-limited pancreatitis, others result in sudden necrotizing injury. The authors developed an improved model providing homogeneous moderately severe injury by superimposing secretory hyperstimulation on minimal intraductal bile acid exposure. Sprague-Dawley rats (n = 231) received low-pressure intraductal glycodeoxycholic acid (GDOC) at very low (5 or 10 mmol/L) concentrations followed by intravenous cerulein. Cerulein or GDOC alone caused only very mild inflammation. However, GDOC combined with cerulein was uniformly associated with more edema (p less than 0.0005), acinar necrosis (p less than 0.01), inflammation (p less than 0.006), and hemorrhage (p less than 0.01). Pancreatic injury was further increased and death was potentiated by increasing volume and duration of intraductal low-dose GDOC infusion. There was significant morphologic progression between 6 and 24 hours. The authors conclude that (1) combining minimal intraductal bile acid exposure with intravenous hyperstimulation produces homogeneous pancreatitis of intermediate severity that can be modulated at will; (2) the injury is progressive over at least 24 hours with finite mortality rate; (3) the model provides superior opportunity to study innovative therapy.

Acute Disease↗

High performance liquid chromatography-mass spectrometry for metabonomics: potential biomarkers for acute deterioration of liver function in chronic hepatitis B.

Metabonomics methods have been successfully applied to the drug discovery, toxicology, phytochemistry, and clinical fields. Here, we report a self-developed metabonomics platform which is based on high performance liquid chromatography-mass spectrometry (HPLC-MS) technique and applied to the investigation of acute deterioration of liver function in chronic hepatitis B to find the potential biomarkers. Sera from 50 healthy persons and 37 patients with acute deterioration of liver function in chronic hepatitis B were analyzed by HPLC-MS after removal of proteins. After de-noise, peak detection and peak alignment, the data of metabolites were fed to partial least squares discriminant analysis (PLS-DA) to find the potential biomarkers. According to the corresponding tandem mass results, several potential biomarkers were identified: Lysophosphatidyl Choline (LPC) C18:0, LPC C16:0, LPC C18:1, LPC C18:2, and glycochenodeoxycholic acid (GCDCA) (or its isomer glycodeoxycholic acid (GDCA)). On the basis of the relevant literature and pathway databases, the biological significance of the present study is discussed.

Adult↗

Isolation and characterization of a Lactobacillus amylovorus mutant depleted in conjugated bile salt hydrolase activity: relation between activity and bile salt resistance.

Growth experiments were conducted on Lactobacillus amylovorus DN-112 053 in batch culture, with or without pH regulation. Conjugated bile salt hydrolase (CBSH) activity was examined as a function of culture growth. The CBSH activity increased during growth but its course depended on bile salts type and culture conditions. A Lact. amylovorus mutant was isolated from the wild-type strain of Lact. amylovorus DN-112 053 after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. An agar plate assay was used to detect mutants without CBSH activity. In resting cell experiments, the strain showed reduced activity. Differences between growth parameters determined for wild-type and mutant strains were not detected. Comparative native gel electrophoresis followed by CBSH activity staining demonstrated the loss of proteins harbouring this activity in the mutant. Four protein bands corresponding to CBSH were observed in the wild-type strain but only one was detected in the mutant. The specific growth rate of the mutant strain was affected more by bile salts than the wild-type strain. Nevertheless, bile was more toxic for the wild-type strain. In viability studies in the presence of nutrients, it was demonstrated that glycodeoxycholic acid exerted a higher toxicity than taurodeoxycholic acid in a pH-dependent manner. No difference was apparent between the two strains. In the absence of nutrients, the wild-type strain died after 2 h whereas no effect was observed for the mutant. The de-energization experiments performed using the ionophores nigericin and valinomycin suggested that the chemical potential of protons (ZDeltapH) was involved in Lactobacillus bile salt resistance.

Amidohydrolases↗