Cholestyramine alters bile acid amounts and the expression of cholesterol-related genes in rabbit intestinal and hepatic tissues.

OBJECTIVE: Cholestyramine (CHO), as a bile acid sequestering exchange resin, has been widely used to treat hypercholesterolemia. The aim of this study was to explore how CHO regulated serum cholesterol amounts and bile acid levels in animal models. METHODS: New Zealand White rabbits were randomly assigned to the control (given distilled water) and CHO-treated (given CHO solution 1 g/kg per day for 2 weeks) groups. To assess bile acid pool size, bile fistulas were constructed in five rabbits in each group. Serum cholesterol levels and biliary and fecal bile outputs were determined. Liver cholesterol 7α-hydroxylase ( CYP7A1 ), small heterodimer partner ( SHP ), bile salt export pump ( BSEP ), ileal bile acid-binding protein ( IBABP ) and LDL receptor ( LDL-R ) mRNA expressions were assessed by real-time polymerase chain reaction. CYP7A1 activity was also determined. RESULTS: CHO treatment decreased serum cholesterol levels by 12.1%. Although CHO did not change the bile acid pool size and biliary bile acid output, it significantly increased fecal bile acid output. Interestingly, CHO also significantly increased the expression and activity of CYP7A1, as well as IBABP and LDL-R mRNA expressions, but decreased hepatic SHP and BSEP gene expressions. CONCLUSION: CHO markedly alters bile acid and cholesterol amounts in rabbit intestinal and liver tissues, downregulating genes responsible for cholesterol homeostasis.

Does Helicobacter pylori infection play a role in iron deficiency anemia? A meta-analysis.

AIM: To perform a meta-analysis of observational studies and randomized controlled trials (RCTs) on the association between Helicobacter pylori (H. pylori) and iron deficiency anemia (IDA). METHODS: A defined search strategy was used to search Medline, Embase, the Cochrane Library, Clinical Trials, Cochrane Central Register of Controlled Trials, Premedline and Healthstar. Odds ratio (OR) was used to evaluate observational epidemiology studies, and weighted mean difference (WMD) was used to demonstrate the difference between control and intervention groups. RESULTS: Fifteen observational studies and 5 RCTs were identified and used for calculation. The pooled OR for observational studies was 2.22 (95% CI: 1.52-3.24, P < 0.0001). The WMD for hemoglobin (HB) was 4.06 g/L (95% CI: -2.57-10.69, P = 0.01), and the WMD for serum ferritin (SF) was 9.47 mug/L (95% CI: -0.50-19.43, P < 0.0001). Results were heterogeneous for all comparisons. CONCLUSION: This meta-analysis on observational studies suggests an association between H. pylori and IDA. In RCTs, eradication of H. pylori can improve HB and SF levels but not significantly.

Interventional effect of Ginkgo biloba extract on the progression of gastric precancerous lesions in rats.

OBJECTIVE: To investigate the effect of Ginkgo biloba extract on gastric precancerous lesions in rats. METHODS: 80 4-week-old Wistar rats were randomly divided into four groups: a control group, a model group, a low and a high dose Ginkgo biloba extract intervention group; 20 in each group. Gastric precancerous lesions were induced by giving them 100 mg/L N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) solution to drink ad libitum for 20 weeks. In addition to the MNNG, the intervention groups were lavaged with Ginkgo biloba extract (0.5 mg/kg/d in the low dose group, 1.5 mg/kg/d in the high dose group) for 20 weeks. Starting from week 21 all the rats were fed with normal rat chow and tap water. At the end of week 30 the rats were killed. The histopathological changes of their gastric mucosa, ISA, NGI, the serum and gastric mucosal SOD/MDA and the expressions of oncogenes were studied. RESULTS: The incidence of mild to severe intestinal metaplasia and dysplasia were significantly lower in the intervention groups than those in the model group (P < 0.01). The ISA and NGI in the intervention groups were significantly lower than those in the model group (P < 0.01). In the intervention groups the activity of SOD was increased and the concentration of MDA was decreased (P < 0.01). Expressions of Bcl-2, c-myc and FasL decreased in the intervention groups, whereas the expression of Fas increased. When compared with the model group, the differences were statistically significant (P < 0.01, P < 0.05, respectively). CONCLUSION: Ginkgo biloba extract can increase anti-oxidative activity and inhibit the progression of gastric precancerous lesions via the regulation of cell proliferation and apoptosis.

Bioconcentration kinetics of PCBs in various parts of the lifecycle of the tadpoles Xenopus laevis.

Polychlorinated biphenyls (PCBs) in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors (BCFs) of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgK(ow) relationship. The relationship between lgBCFs and lgK(ow) followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgK(ow), suggesting that a metabolism of the higher K(ow)' PCB congeners occurred. These results support the author's conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners.

L-[1-13C] phenylalanine breath test results reflect the activity of phenylalanine hydroxylase in carbon tetrachloride acute injured rat liver.

L-[1-13C] phenylalanine breath tests (PheBTs) have been used to determine the hepatocyte functional capacity of patients. This study investigated the relationship between the PheBT parameter 13C excretion rate constant (PheBT-k) and activity of the phenylalanine metabolic rate-limiting enzyme phenylalanine hydroxylase (PAH) in rat liver. We noted that the time-course curves of 13C excretion presented as a single peak, which appeared 2 min after administration of L-[1-13C] phenylalanine (13C-Phe). 13C excretion during exhalation can be divided into a slow phase and a rapid phase. The PheBT-k in rats with carbon tetrachloride acute liver injury was.significantly lower than that of control rats. The rapid phase 13C disposition constants of the acute liver injured rats did not differ from that of the controls. The peak value of 13C abundance in the breath of the acute liver injured rats was markedly higher than that of the control group. Total liver PAH activity in the acute liver injured rats was significantly lower than that in the control group. PheBT-k was highly correlated with the total activity of liver PAH (r = 0.92, P < 0.001). The present findings indicate that PheBT results reflect PAH activity levels. The PheBT-k parameter is a sensitive index that can be used to evaluate PAH function in the liver. In addition we demonstrated that the rodent model used in this study is a valuable tool for basic research studies of the breath test.

[Expressions of aquaporin-1 on peritonea in hepatic cirrhotic rats with ascites].

OBJECTIVE: To investigate the changes of aquaporin (AQP-1) expressions on peritonea in liver cirrhotic rats with ascites, and to study the correlation between AQP-1 expressions and ascites form. METHODS: 32 healthy Sprague-Dawley (SD) rats were divided into two groups randomly, 20 rats were used to produce liver cirrhotic models induced with phenobarbitol sodium and CCl(4). The distribution and protein expressions of AQP-1 on the rats' peritonea were measured with immunohistochemistry assay, and the expressions of APQ-1 mRNA were tested with relative GAPDH quantitative RT-PCR. RESULTS: (1) The expressions of AQP-1 were mainly on the endothelial cells of capillary vessels and venules on the rats' peritonea, and also on mesothelial cells. (2) There was no statistically significant difference between the expressions of AQP-1 protein and mRNA in the two groups on the early stage of liver cirrhosis. (3) Downregulations of the expressions of AQP-1 protein and mRNA were observed in B group on the advanced cirrhotic stage. CONCLUSION: Expressions of AQP-1 were downregulated on the peritonea of rats with decompensated liver cirrhosis, which may play a role in the formation of ascites. The changes of AQP-1 Expressions on peritoneal mesothelial cells which were fewer than those on the endothelial cells may be few relations to ascites form.

Clinical application of 13C-Hiolein breath test in assessing pancreatic exocrine insufficiency.

OBJECTIVE: To examine the feasibility and significance of 13C-Hiolein breath test in evaluating chronic pancreatitis-related exocrine insufficiency and efficacy of enzyme treatment. METHODS: The 13C-Hiolein breath test was used in 8 healthy volunteers (group 1), 8 chronic pancreatitis (CP) patients without steatorrhea (group 2), and 8 CP patients with steatorrhea (group 3). To evaluate the function of pancreatic exocrine, 13CO2 was determined following 13C-Hiolein diet. The 13C-Hiolein test was repeated in group 3 after enzyme supplement therapy. RESULTS: Administration of 13C-Hiolein diet resulted in significantly higher cumulative percent dose of 13C recovery per 6 h (cPDR/6 h) and maximal PDR (PDR(peak)) in the healthy controls (group 1) than the CP patients with steatorrhea (group 3) (11.22%+/-1.22% and 6.11%+/-0.59% vs 2.87%+/-0.73% and 1.53%+/-0.36%, respectively, both P<0.01). In the CP patients with steatorrhea (group 3), a repeated test after enzyme supplementation therapy showed a significant elevation of both cPDR/6 h and PDR(peak) (9.03%+/-0.84% and 2.33%+/-0.47%, both P<0.01 compared with those before enzyme treatment), but cPDR/6 h remained significantly lower than that in the healthy volunteers (group 1, P<0.05). Both cPDR and PDR(peak) in the CP patients without steatorrhea (group 2) were similar to those in the healthy controls (group 1, both P>0.05). CONCLUSION: The results of 13C-Hiolein breath test well reflect fat metabolism status in CP patients, and the test can be used to monitor the efficacy of pancreatic enzymes therapy.