Browsing by Author "Arrese, M"

Now showing 1 - 11 of 11
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    Accuracy of invasive and noninvasive tests to diagnose Helicobacter pylori infection after antibiotic treatment
    (WILLIAMS & WILKINS, 1997) Rollan, A; Giancaspero, R; Arrese, M; Figueroa, C; Vollrath, V; Schultz, M; Duarte, I; Vial, P
    Objectives: To compare the diagnostic accuracy of the most widely available tests for diagnosis of Helicobacter pylori infection after antibiotic treatment, Methods: A total of 59 H, pylori-positive, duodenal ulcer patients (mean age, 40.7 +/- 11.7 yr; 40 male and 19 female) were treated for 2 wk with either amoxicillin-metronidazole (n = 36) or omeprazole-amoxicillin-tinidazole (n = 23), and after 4 wk, were tested for H, pylori infection by [C-14]urea breath test (UBT), serum IgG antibody level, and multiple antral biopsies for rapid urease testing, histology, Warthin-Starry stain, and polymerase chain reaction to detect H, pylori DNA, Infection status was established by a concordance of test results, Results: H, pylori was eradicated in 47 patients (80%), UBT and rapid urease testing had the best sensitivity and specificity, although not statistically different to Warthin-Starry stain and polymerase chain reaction, Serology and histology had little diagnostic value in this setting due to high proportion of false-positive results, Conclusions: Noninvasive UBT is as accurate in predicting H, pylori status after antibiotic treatment as rapid urease testing and Warthin-Starry stain, Especially for duodenal ulcer patients, UBT could be considered the gold standard to confirm eradication of H, pylori.
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    Adaptive regulation of hepatic bile salt transport: Role of bile salt hydrophobicity and microtubule-dependent vesicular pathway
    (MUNKSGAARD INT PUBL LTD, 1997) Arrese, M; Pizarro, M; Solis, N; Accatino, L
    Background/Aims: The hepatic transport of bile salts can be regulated by changes in bile salt pool size and/ or in the flux of bile salts through the liver, Prolonged bile salt pool depletion is associated with down-regulation of maximum taurocholate transport and decreased canalicular membrane specific bile salt binding sites, This study was undertaken to investigate: a) whether adaptive down-regulation of maximum hepatic bile salt transport occurs to the same extent for bile acids of different hydrophobicity; and b) the role of microtubule-dependent vesicular pathway in the adaptive changes of bile salt transport capacity.
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    Bile secretory function after warm hepatic ischemia-reperfusion injury in the rat
    (WILEY, 2003) Accatino, L; Pizarro, M; Solis, N; Arrese, M; Koenig, CS
    Hepatic ischemia-reperfusion (I-R) injury frequently is associated with cholestasis. However, the underlying mechanisms are not fully understood. The aim of the study is to assess bile secretory function in vivo in rats subjected to warm lobar hepatic ischemia at different times during reperfusion. A model of lobar 70% warm hepatic ischemia for 30 minutes was used with studies conducted at 1 and 6 hours and 1, 3, and 7 days after reperfusion. Bile secretory function was assessed after selective cannulation of bile ducts of ischemic (ILs) and nonischemic lobes (NILs). Serum activity of hepatic alanine and aspartate aminotransferase was slightly increased in rats subjected to I-R, whereas serum bile salt levels increased early during reperfusion, returning to control values after 7 days. ILs; showed mild reversible leukocyte infiltration and no significant necrosis. Bile flow and bile salt excretion were significantly decreased in ILs during the first 24-hour reperfusion period compared with shamoperated rats and NILs. A marked reduction in glutathione (GSH) excretion occurred at I and 6 hours and I and 3 days, which returned to control values after 7 days. Total GSH and both reduced and oxidized GSH levels in liver homogenate and arterial blood GSH levels were unchanged at all times. Protein mass of multidrug resistance protein 2 and its function, assessed by the hepatic maximum secretory rate of ceftriaxone, did not show significant changes in ILs or NILs compared with shamoperated rats. Liver tissue gamma-glutamyl transpeptidase (GGT) and gamma-glutamylcysteine synthetase activities remained unchanged, whereas biliary GGT and cysteine secretory rates were significantly increased in ILs; and NILs. Administration of acivicin, a GGT inhibitor, resulted in decreased secretion of this enzyme into bile and a parallel marked increase in biliary GSH secretion compared with untreated ischemic rats. In conclusion, warm hepatic I-R induces reversible cholestatic changes in ILs. GSH secretory rates from both ILs and NILs were markedly decreased during reperfusion. The reversibility of this effect after GGT inhibition, as well as increased release of active GGT into bile and cysteine biliary secretory rates, suggest increased GSH degradation in bile. These findings might be relevant for the I-R-induced clinical cholestasis, as well as cholangiocyte injury, seen after hepatic ischemia.
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    Bile secretory function in the obese Zucker rat: evidence of cholestasis and altered canalicular transport function
    (BMJ PUBLISHING GROUP, 2004) Pizarro, M; Balasubramaniyan, N; Solis, N; Solar, A; Duarte, I; Miquel, JF; Suchy, FJ; Trauner, M; Accatino, L; Ananthanarayanan, M; Arrese, M
    Background: Obese Zucker rats (ZR) have been used as an experimental model for non-alcoholic fatty liver disease and are particularly susceptible to various types of liver injury. Bile secretory function has not been assessed in ZR.
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    Differential expression of canalicular membrane Ca2+/Mg2+-ecto-ATPase in estrogen-induced and obstructive cholestasis in the rat
    (MOSBY, INC, 2000) Accatino, L; Pizarro, M; Solis, N; Arrese, M; Vollrath, V; Ananthanarayanan, M; Chianale, J; Koenig, CS
    Extracellular adenosine triphosphate (ATP) may regulate hepatocyte and cholangiocyte functions, and under some conditions it may have deleterious effects on bile secretion and cause cholestasis. The canalicular membrane enzyme Ca2+/Mg2+-ecto-ATPase (ecto-ATPase) hydrolyzes ATP/adenosine diphosphate (ATP/ADP) and regulates hepatic extracellular ATP concentration. Changes in liver ecto-ATPase in estrogen-induced cholestasis were examined in male rats receiving 17 alpha-ethinylestradiol (E groups) for 1, 3, or 5 days (5 mg/kg/day, sc) and compared with changes in rats subjected to obstructive cholestasis (O groups) for 1, 3, or 8 days. Activity of ecto-ATPase, protein mass in canalicular membranes and bile (estimated by Western blotting), steady state mRNA levels (by Northern blotting), and cellular and acinar distributions of the enzyme (histochemistry and immunocytochemistry) were assessed in these groups. Activity of ecto-ATPase, protein mass in isolated canalicular membranes, and enzyme mRNA levels were significantly increased in E group rats as compared with controls. In contrast, these parameters were markedly decreased in O group rats, and the enzyme protein was undetectable in bile. The ecto-ATPase histochemical reaction was markedly increased in the canalicular membrane of E group rats, extending from acinar zone 2 to zone 1,whereas it decreased in the O group. The ecto-ATPase immunocytochemical reaction was present in the canalicular membrane and pericanalicular vesicles in control and E group hepatocytes, but it decreased in obstructive cholestasis and was localized only to the canalicular membrane. Thus, significant changes in liver ecto-ATPase were apparent in 17 alpha-ethinylestradiol-induced cholestasis that were opposite to those observed in obstructive cholestasis. Assuming that the alterations observed in obstructive cholestasis are the result of the cholestatic phenomenon, we conclude that changes in ecto-ATPase in 17 alpha-ethinylestradiol-treated rats might be either primary events or part of an adaptive response in 17 alpha-ethinylestradiol-induced cholestasis.
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    Down-regulation of the Na+/taurocholate cotransporting polypeptide during pregnancy in the rat
    (ELSEVIER SCIENCE BV, 2003) Arrese, M; Traumer, M; Ananthanarayanan, M; Pizarro, M; Solis, N; Accatino, L; Soroka, C; Boyer, JL; Karpen, SJ; Miquel, JF; Suchy, FJ
    Background: Experimental studies have shown decreased bile acid (BA) uptake and reduced excretion of cholephilic compounds in pregnant rodents.
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    Hepatic overexpression of caveolins increases bile salt secretion in mice
    (WILEY, 2003) Moreno, M; Molina, H; Amigo, L; Zanlungo, S; Arrese, M; Rigotti, A; Miquel, JF
    Caveolins are cholesterol-binding proteins involved in the regulation of several intracellular processes, including cholesterol transport. Because hepatocytes express caveolin-1 and caveolin-2, these proteins might modulate hepatic lipid metabolism and biliary lipid secretion. Our aim was to investigate the potential physiologic role of caveolins in hepatic cholesterol and bile salt (BS) metabolism and transport using adenoviral gene transfer. C57BL/6 mice were infected with recombinant human caveolin-1 and caveolin-2 adenoviruses. Mice infected with adenovirus lacking the transgene were used as controls. Hepatic caveolin expression was evaluated by immunochemical methods. Reverse-transcription polymerase chain reaction (RT-PCR) and immunoblotting were used to assess messenger RNA (mRNA) levels and protein mass of BS transporters (sodium taurocholate cotransporting polypeptide [Ntcp] and bile salt export pump [Bsep]). Serum, liver, biliary, and fecal biochemical determinations and BS maximal secretory rate (SRm) were performed by standard methods. Ad.Cav-1- and Ad.Cav-2-infected mice exhibited a 10- and 7-fold increase in hepatic caveolin-1 and caveolin-2 protein expression, respectively. Caveolin-1-overexpressing mice had a significant increase in plasma high-density lipoprotein (HDL) cholesterol and hepatic free cholesterol content, whereas total plasma cholesterol and triglyceride levels remained unchanged. Hepatic caveolin-1 and/or caveolin-2 overexpression significantly increased bile flow and secretion of all biliary lipids. Caveolin-1-overexpressing mice showed a 2.5-fold increase in taurocholate (TC) SRm, indicating increased canalicular BS transport capacity. BS pool size and fecal BS excretion remained within the normal range in mice with Cav-1 overexpression. No changes were seen in the protein mass of BS transporters NtcP and Bsep. In conclusion, our findings indicate that caveolins may play an important role in regulating hepatic BS and cholesterol metabolism.
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    Ileal bile acid transport regulates bile acid pool, synthesis, and plasma cholesterol levels differently in cholesterol-fed rats and rabbits
    (LIPID RESEARCH INC, 2000) Xu, GR; Shneider, BL; Shefer, S; Nguyen, LB; Batta, AK; Tint, GS; Arrese, M; Thevananther, S; Ma, L; Stengelin, S; Kramer, W; Greenblatt, D; Pcolinsky, M; Salen, G
    We investigated the effect of heal bile acid transport on the regulation of classic and alternative bile acid synthesis in cholesterol-fed rats and rabbits. Bile acid pool sizes, fecal bile acid outputs (synthesis rates), and the activities of cholesterol 7 alpha-hydroxylase (classic bile acid synthesis) and cholesterol 27-hydroxylase (alternative bile acid synthesis) were related to heal bile acid transporter expression (ileal apical sodium-dependent bile acid transporter, ASBT). Plasma cholesterol levels rose 2.1-times in rats (98 +/- 19 mg/dl) and 31-times (986 +/- 188 mg/dl) in rabbits. The bile acid pool size remained constant (55 +/- 17 mg vs. 61 +/- 18 mg) in rats but doubled (254 +/- 46 to 533 +/- 53 mg) in rabbits. ASBT protein expression did not change in rats but rose 31% (P < 0.05) in rabbits, Fecal bile acid outputs that reflected bile acid synthesis increased 2- and 2.4-times (P < 0.05) in cholesterol-fed rats and rabbits, respectively. Cholesterol 7 alpha-hydroxylase activity rose 33% (24 +/- 2.4 vs. 18 +/- 1.6 pmol/mg/min, P < 0.01) and mRNA levels increased 50% (P < 0.01) in rats but decreased 68% and 79%, respectively, in cholesterol-fed rabbits. Cholesterol 27-hydroxylase activity remained unchanged in rats but rose 62% (P < 0.05) in rabbits. Classic bile acid synthesis (cholesterol 7 alpha-hydroxylase) was inhibited in rabbits because an enlarged bile acid pool developed from enhanced ileal bile acid transport. In contrast, in rats, cholesterol 7 alpha-hydroxylase was stimulated but the bile acid pool did not enlarge because ASBT did not change. jlr Therefore, although bile acid synthesis was increased via different pathways in rats and rabbits, enhanced ileal bile acid transport was critical for enlarging the bile acid pool size that exerted feedback regulation on cholesterol 7 alpha-hydroxylase in rabbits.
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    Molecular analysis of the adaptive response of intestinal bile acid transport after ileal resection in the rat
    (W B SAUNDERS CO-ELSEVIER INC, 1998) Coppola, CP; Gosche, JR; Arrese, M; Ancowitz, B; Madsen, J; Vanderhoof, J; Shneider, BL
    Background & Aims: The apical sodium-dependent bile acid transporter is critical for intestinal reclamation of bile salts, Its expression and activity, along with the ileal lipid-binding protein, were studied before and after intestinal resection in the rat. Methods: The effects of surgical resection and bile acid feeding on the expression of ileal bile acid transport were assessed by a combination of functional (taurocholate uptake into crude brush border membrane vesicles) and molecular assays (Northern and Western blotting), Results: Transport, apical sodium-dependent bile acid transporter and ileal lipid-binding protein messenger RNA and protein expression were restricted to the distal 30 cm of ileum. After resection, transport and expression were limited to the remaining portions of this segment, Limited ileal resection increased protein mass and, therefore, transport in the terminal 5 cm of ileum without a specific increase in transporter gene expression, increased bile acid presentation to the terminal ileum did not induce ileal hyperplasia. Eighty-five percent intestinal resection led to ileal hypertrophy and a specific repression in bile acid transport activity. Conclusions: Native and compensatory bile acid transporter gene expression occur predominantly in the terminal 30 cm of ileum. The specific ileal responses to intestinal resection are dependent on the extent of resection.
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    Saccharomyces cerevisiae fungemia after Saccharomyces boulardii treatment in immunocompromised patients
    (LIPPINCOTT WILLIAMS & WILKINS, 2003) Riquelme, AJ; Calvo, MA; Guzman, AM; Depix, MS; Garcia, P; Perez, C; Arrese, M; Labarca, JA
    Saccharomyces boulardii is widely used as a probiotic compound. Clinical data suggest that this agent is safe and effective. We report two cases of fungemia caused by S. cerevisiae occurring in immunosuppressed patients treated orally with S. boulardii. Molecular typing confirmed clonality in isolate strains from patients and the S. boulardii capsule. Physicians caring for immunosuppressed patients must be aware of this potential serious complication of probiotic use.
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    Successful liver transplantation and delivery in a woman with fulminant hepatic failure occurring during the second trimester of pregnancy
    (WILEY, 2006) Jarufe, N; Soza, A; Perez Ayuso, RM; Poblete, JA; Gonzalez, R; Guajardo, M; Hernandez, V; Riquelme, A; Arrese, M; Martinez, J
    Background: Severe liver dysfunction occurring during pregnancy is an unusual but dramatic event that poses special technical and ethical issues because it involves two lives. Methods an Results: We report the case of a 35-year-old woman with cryptogenic fulminant hepatic failure who underwent successful orthotopic liver transplantation at 22 weeks of pregnancy. After a relatively uneventful post-operative course she delivered a normal offspring at the 27th week of gestation. There were no obstetrical complications and neonatal outcome was excellent. After a year of follow-up, the patient is doing well,and the newborn has exhibited normal psychomotor and weight/height development. Conclusions: This case illustrates the challenge of treating fulminant hepatic failure during pregnancy and demonstrates that liver transplantation is a feasible therapeutic option for treatment of patients with this condition, allowing successful completion of pregnancy.