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Biomedical subjects

Mario Rizzetto

Publications and source records attributed to Mario Rizzetto.

At least 37 records · Page 2Linked to original sources
PubMed2005

Plasma adiponectin in nonalcoholic fatty liver is related to hepatic insulin resistance and hepatic fat content, not to liver disease severity.

Plasma levels of adiponectin are decreased in patients with nonalcoholic fatty liver disease (NAFLD), but the relationship among plasma adiponectin, insulin sensitivity, and histological features is unclear. In 174 NAFLD patients and 42 controls, we examined plasma adiponectin concentrations in relation to 1) lipid profile, indices of insulin resistance, and features of the metabolic syndrome (n = 174); 2) hepatic insulin resistance (clamp technique with tracer infusion) (10 patients); and 3) histological features at liver biopsy (n = 116). When the data from all subjects were combined, plasma adiponectin levels were positively associated with increased age, female gender, and plasma high-density lipoprotein levels, and negatively associated with waist circumference, body mass index, triglycerides, indices of insulin resistance, and aminotransferase levels, and also predicted the presence of the metabolic syndrome. In step-wise regression, increased age, female gender, waist circumference, triglyceride levels, and homeostasis model assessment independently associated with adiponectin (adjusted R(2), 0.329). In NAFLD, adiponectin was only associated with increased age, female gender, and triglycerides (adjusted R(2), 0.245). When the measured histological parameters were included in the model, plasma adiponectin levels were also inversely proportional to the percentage of hepatic fat content (adjusted R(2), 0.221), whereas necroinflammation and fibrosis did not fit in the model. Adiponectin was negatively correlated with insulin-suppressed endogenous glucose production during the clamp (P = 0.011). The results demonstrate that decreased levels of circulating adiponectin in NAFLD are related to hepatic insulin sensitivity and to the amount of hepatic fat content. Hypoadiponectinemia in NAFLD is part of a metabolic disturbance characterized by ectopic fat accumulation in the central compartment.

Adiponectin↗
PubMed2005

Randomized trial of different screening strategies for colorectal cancer: patient response and detection rates.

BACKGROUND: Although there is general consensus concerning the efficacy of colorectal cancer screening, there is a lack of agreement about which routine screening strategy should be adopted. We compared the participation and detection rates achievable through different strategies of colorectal cancer screening. METHODS: From November 1999 through June 2001 we conducted a multicenter, randomized trial in Italy among a sample of 55-64 year olds in the general population who had an average risk of colorectal cancer. People with previous colorectal cancer, adenomas, inflammatory bowel disease, a recent (< or =2 years) colorectal endoscopy or fecal occult blood test (FOBT), or two first-degree relatives with colorectal cancer were excluded. Eligible subjects were randomly assigned, within the roster of their general practitioner, to 1) biennial FOBT (delivered by mail), 2) biennial FOBT (delivered by general practitioner or a screening facility), 3) patient's choice of FOBT or "once-only" sigmoidoscopy, 4) "once-only" sigmoidoscopy, or 5) sigmoidoscopy followed by biennial FOBT. An immunologic FOBT was used. Participation and detection rates of the strategies tested were compared using multivariable logistic regression models that adjusted for age, sex, and screening center. All statistical tests were two-sided. RESULTS: Of 28 319 people sampled, 1637 were excluded and 26 682 were randomly assigned to a screening arm. After excluding undelivered letters (n = 427), the participation rates for groups 1, 2, 3, 4, and 5 were 30.1% (682/2266), 28.1% (1654/5893), 27.1% (970/3579), 28.1% (1026/3650), and 28.1% (3049/10 867), respectively. Of the 2858 subjects screened by FOBT, 122 (4.3%) had a positive test result, 10 (3.5 per 1000) had colorectal cancer, and 39 (1.4%) had an advanced adenoma. Among the 4466 subjects screened by sigmoidoscopy, 341 (7.6%) were referred for colonoscopy, 18 (4 per 1000) had colorectal cancer, and 229 (5.1%) harbored an advanced adenoma. CONCLUSIONS: The participation rates were similar for sigmoidoscopy and FOBT. The detection rate for advanced neoplasia was three times higher following screening by sigmoidoscopy than by FOBT.

Colonic Polyps↗
PubMed2005

Prophylaxis of hepatitis B virus recurrence after liver transplantation in carriers of lamivudine-resistant mutants.

The combination of lamivudine and hepatitis B immunoglobulin (HBIG) reduces the risk of hepatitis B virus (HBV) recurrence after liver transplantation (LT). However, the efficacy of this strategy and the need for combined therapy with adefovir dipivoxil (ADV) in patients who select lamivudine-resistant strains (YMDD) before surgery is still unknown. Twenty-two patients treated with lamivudine (LAM) who underwent LT after YMDD-mutant selection were studied. In 13 patients, YMDD mutants were associated with an HBV DNA breakthrough greater than 5 log10 (group A: phenotypic resistance), and 11 were treated with ADV to decrease viral load before LT. In the remaining 9 patients who did not experience the viral breakthrough, YMDD mutants were detected only retrospectively in sera stored at the time of LT (group B: genotypic resistance). During 35 months of post-LT follow-up, none of the 11 patients of group A treated with ADV before and after surgery (in addition to HBIG and LAM) had HBV recurrence, and neither did any of the 7 subjects of group B treated with LAM before and after transplantation (in addition to HBIG). HBV recurred in 2 patients of group A (untreated with ADV before surgery and transplanted with an HBV DNA exceeding 5 log10) and in 2 subjects of group B (who spontaneously stopped HBIG after surgery). In carriers of YMDD mutants, the risk of post-LT HBV recurrence is low, provided that preemptive and prophylactic ADV (in addition to LAM and HBIG) treatment is used in highly viremic patients and prophylactic LAM (or ADV) and HBIG therapy is continued in low viremic patients.

Adenine↗
PubMed2005

Viral load at the time of liver transplantation and risk of hepatitis B virus recurrence.

Hepatitis B virus (HBV) recurrence after liver transplantation is significantly reduced by prophylaxis with hepatitis B immune globulins (HBIG) or antiviral drugs in nonreplicating patients and by the combination of both drugs in replicating patients. However, the load of HBV DNA, which defines replicating status in patients undergoing liver transplantation, remains unclear. This study analyzes the correlation between the viral load, tested with a single amplified assay, at the time of liver transplantation, and the risk of hepatitis B recurrence in 177 HBV carriers who underwent transplantation in a single center from 1990 to 2002. Overall, HBV relapsed after surgery in 15 patients (8.5%) with a 5- and 8-year actuarial rate of recurrence of 8% and 21%, respectively. After liver transplantation hepatitis B recurred in 9% of 98 selected subjects treated only with immune globulins and in 8% of 79 viremic patients who received immune globulins and lamivudine (P = NS). A linear correlation was observed between recurrence and viral load at the time of surgery. In transplant patients with HBV DNA higher than 100,000 copies/mL, 200-99,999 copies/mL, and DNA undetectable by amplified assay, hepatitis B recurred in 50%, 7.5%, and 0% of patients, respectively. Overall, a viral load higher than 100,000 copies/mL at the time of liver transplantation was significantly associated with hepatitis B recurrence (P = .0003). In conclusion, spontaneous or antiviral-induced HBV DNA viral load at the time of surgery classifies the risk of HBV recurrence after liver transplantation and indicates the best prophylaxis strategy.

Adult↗
PubMed2005

Loss of tubuloglomerular feedback in decompensated liver cirrhosis: physiopathological implications.

In healthy subjects, arterial pressure reduction or renal ischemia produces renal artery dilatation through autoregulation and tubuloglomerular feedback (TuGF). Patients with decompensated cirrhosis have reduced kidney perfusion pressure but show renal vasoconstriction instead of autoregulation-mediated vasodilation. This study investigates the consequences of kidney autoregulation loss on renal perfusion, glomerular filtration rate, and tubular handling of electrolytes in both compensated and ascitic nonazotemic cirrhotic patients. Forty-two consecutive patients with diuretic-free liver cirrhosis (32 with preascitic and 10 with ascitic disease) and 10 controls were submitted to the following determinations: (a) basal plasma renin activity and aldosterone levels; (b) endogenous dopaminergic activity measured as incremental aldosterone responses during metoclopramide administration; and (c) renal clearances of sodium, potassium, inulin, para-aminohippurate and lithium. Compared with the other groups, ascitic patients showed lower renal plasma flow (P < 0.01) and lithium clearance (P < 0.05), a higher filtration fraction (P < 0.01), and secondary aldosteronism. Controls and preascitic patients displayed tubuloglomerular feedback (the mechanism increasing the glomerular filtration rate when a reduced sodium load reaches the distal tubule), as demonstrated by negative correlations between fractional excretion of lithium (an expression of fractional delivery of sodium to the distal nephron) and glomerular filtration rate (respectively, r = -0.73, P < 0.03, and r = -0.48, P < 0.01). Conversely, patients with ascites showed a positive correlation between lithium fractional excretion and glomerular filtration rate (r = 0.64, P < 0.05). Reduction in renal perfusion, increased filtration fraction, and TuGF derangement, as found in decompensated patients, are indicative of prevalent postglomerular arteriolar vasoconstriction, with ensuing stimulation of proximal tubular sodium reabsorption.

Adult↗
PubMed2005

Extended lamivudine treatment in patients with HBeAg-negative chronic hepatitis B.

BACKGROUND/AIMS: The histological and clinical outcome of lamivudine 100mg/day was assessed in 76 HBeAg-negative chronic hepatitis B patients previously randomised to a double-blind comparison study of lamivudine and placebo. METHODS: Paired liver biopsies were available before 1 year of randomised lamivudine treatment and after 2 years of further open-label treatment for 48 patients. Serum samples were analysed for hepatitis B markers and ALT levels (n=74). RESULTS: The histological activity index improved, remained unchanged and worsened in 64, 32 and 5%, respectively, for patients without YMDD-variant HBV compared to 15, 54 and 31% with the variant. None of the 42/48 patients without cirrhosis at baseline progressed to cirrhosis. Of 24/48 patients without bridging fibrosis at pre-treatment, 83% (20/24) did not progress to bridging fibrosis. Median HBV DNA remained below the lower limit of detection and ALT < or =1 times the ULN for patients without the variant whereas levels gradually increased to 11.3Meq/ml (bDNA assay) and 2 times the upper limit of normal by month 24 for patients with variant. CONCLUSIONS: The clinical benefit of lamivudine is greatest for patients without YMDD variants over 2 years of extended treatment. Additional therapies should be considered for patients with YMDD variants.

DNA, Viral↗
PubMed2005

A dose-ranging study of the efficacy and tolerability of entecavir in Lamivudine-refractory chronic hepatitis B patients.

BACKGROUND & AIMS: Entecavir is a nucleoside analogue with potent in vitro activity against lamivudine-resistant hepatitis B virus (HBV). This randomized, dose-ranging, phase 2 study compared the efficacy and safety of entecavir with lamivudine in lamivudine-refractory patients. METHODS: Hepatitis B e antigen (HBeAg)-positive and -negative patients (n = 182), viremic despite lamivudine treatment for > or =24 weeks or having documented lamivudine resistance substitutions, were switched directly to entecavir (1.0, 0.5, or 0.1 mg daily) or continued on lamivudine (100 mg daily) for up to 76 weeks. RESULTS: At week 24, significantly more patients receiving entecavir 1.0 mg (79%) or 0.5 mg (51%) had undetectable HBV DNA levels by branched chain DNA assay compared with lamivudine (13%; P < .0001). Entecavir 1.0 mg was superior to entecavir 0.5 mg for this end point (P < .01). After 48 weeks, mean reductions in HBV DNA levels were 5.06, 4.46, and 2.85 log(10) copies/mL on entecavir 1.0, 0.5, and 0.1 mg, respectively, significantly higher than 1.37 log(10) copies/mL on lamivudine. Significantly higher proportions of patients achieved normalization of alanine aminotransferase levels on entecavir 1.0, 0.5, and 0.1 mg (68%, 59%, and 47%, respectively) than on lamivudine (6%). One virologic rebound due to resistance occurred (in the 0.5-mg group). CONCLUSIONS: In HBeAg-positive and HBeAg-negative lamivudine-refractory patients, treatment with entecavir 1.0 and 0.5 mg daily was well tolerated and resulted in significant reductions in HBV DNA levels and normalization of alanine aminotransferase levels. One milligram of entecavir was more effective than 0.5 mg in this population.

Adult↗
PubMed2005

Signal transducers and activators of transcription 3 signaling pathway: an essential mediator of inflammatory bowel disease and other forms of intestinal inflammation.

Crohn's disease (CD) and ulcerative colitis (UC), the two major forms of chronic inflammatory bowel disease (IBD), are characterized by mucosal immune cell activation that is driven by a cytokine imbalance. Several cytokines involved in IBD act through the activation of the signal transducers and activators of transcription (STAT) family. We investigated the activation of STAT3 in the mucosa of CD and UC patients, and evaluated whether this event is specific for IBD patients. Using immunofluorescence and immunoblotting, total and phosphorylated STAT3 levels were assessed in biopsy specimens, isolated lamina propria mononuclear cells, and peripheral blood mononuclear cells from patients with CD, UC, other forms of intestinal inflammation, and control subjects. Immunoblotting revealed phosphorylated STAT3 in mucosal biopsy specimens from patients with CD, UC, celiac disease, and acute self-limited colitis, but not in the normal mucosa of control subjects. In IBD patients, STAT3 activation was confined to actively inflamed areas. Accordingly, activated STAT3 was detected in isolated lamina propria mononuclear cells from inflamed IBD tissues, but not in peripheral blood mononuclear cells from control subjects or IBD patients. Immunofluorescence demonstrated that the sources of activated STAT3 were macrophages and T lymphocytes, but not neutrophils. STAT3 activation also was detected in T cells infiltrating the duodenal mucosa of celiac disease patients. We conclude that STAT3 signaling occurs in both CD and UC, where it is strictly confined to areas of active inflammation and is limited to infiltrating macrophages and T cells. The occurrence of STAT3 signaling in other acute and chronic intestinal inflammatory conditions suggests that, rather than a specific feature of IBD, it represents a fundamental signaling pathway that is shared by multiple forms of gut inflammation.

Adult↗
PubMed2005

The first one thousand liver transplants in Turin: a single-center experience in Italy.

The first Italian liver transplant center to reach the goal of 1000 procedures was Turin. The paper reports this single-center experience, highlighting the main changes that have occurred over time. From 1990 to 2002, 1000 consecutive liver transplants were performed in 910 patients, mainly cirrhotics. Surgical technique was based on the preservation of the retrohepatic vena cava of the recipient. The veno-venous bypass was used in 30 cases only and abandoned since 1997. Operating time, warm ischemia time and length of hospital stay significantly decreased over the years, while operating room extubation became routine. Immunosuppression pivoted on cyclosporine A. Management of retransplantations, marginal grafts, and of HCV-positive, HBV-positive and hepatocellular carcinoma recipients were optimized. Median follow-up of the patients was 41 months. Overall survival rates at 1, 5 and 10 years were 87%, 78% and 72% respectively. Survival rates obtained in the second half of the cases (1999-2002 period) were significantly better than those obtained in the first half (1990-1998 period) (90% vs. 83% at 1 year and 81% vs. 76% at 5 years respectively). Increasing experience in liver transplant surgery and postoperative care allowed standardization of the procedure and expansion of the activity, with parallel improvement of the results.

Adolescent↗
PubMed2005

Hypoadiponectinemia predicts the severity of hepatic fibrosis and pancreatic Beta-cell dysfunction in nondiabetic nonobese patients with nonalcoholic steatohepatitis.

OBJECTIVES: The relationships between the adipokines tumor necrosis factor (TNF)-alpha and adiponectin and the parameters of glucose homeostasis and severity of liver disease were assessed in nonobese nondiabetic subjects with nonalcoholic steatohepatitis (NASH). METHODS: A frequently sampled intravenous glucose tolerance test, serum cytokine measurement, and 7-day alimentary record were performed in 20 biopsy-proven NASH patients and 45 age-, sex-, and BMI-matched controls (30 insulin sensitive and 15 insulin resistant). RESULTS: Patients with NASH had impaired pancreatic beta-cell function compared with both insulin-sensitive (adaptation index, AI: 97.7 +/- 17.7 vs 307.4 +/- 24.1 min(-2) mmol(-1) L; p= 0.00001) and insulin-resistant (adaptation index, AI: 97.7 +/- 17.7 vs 201.4 +/- 41.1 min(-2) mmol(-1) L; p= 0.001) controls. Serum adiponectin levels were also significantly lower in the NASH group than in the two control groups and correlated with adaptation index and with the severity of hepatic steatosis, necroinflammation, and fibrosis. When NASH patients were grouped according to the severity of histological liver damage, adiponectin was the only variable discriminating patients with higher necroinflammatory grade and fibrosis score from those with milder lesions. CONCLUSIONS: Beta-cell secretory impairment is present in nonobese patients with NASH before glucose intolerance appears and may contribute to their increased risk for developing diabetes. Hypoadiponectinemia is a feature of NASH and may have a pathogenetic role in beta-cell dysfunction and in hepatic necroinflammation and fibrosis, independently of insulin resistance, visceral fat accumulation, TNF-alpha axis activity, and dietary habits. Our findings provide further rationale for therapeutic approaches aimed at increasing adiponectin levels together with restoring beta-cell function and insulin sensitivity.

Adaptation, Physiological↗
PubMed2005

A randomized controlled trial of metformin versus vitamin E or prescriptive diet in nonalcoholic fatty liver disease.

OBJECTIVES: Metformin proved useful in the treatment of nonalcoholic fatty liver disease (NAFLD), but its superiority over nutritional treatment and antioxidants has never been demonstrated. We aimed to compare the usefulness of metformin versus prescriptive diet or vitamin E. METHODS: In an open label, randomized trial, nondiabetic NAFLD patients were given metformin (2 g/day; n = 55) for 12 months. The control cases were given either vitamin E (800 IU/day; n = 28) or were treated by a prescriptive, weight-reducing diet (n = 27). Outcome measures were liver enzymes, insulin resistance (homeostasis model assessment), parameters of the metabolic syndrome, and histology. RESULTS: Aminotransferase levels improved in all groups, in association with weight loss. The effects in the metformin arm were larger (p < 0.0001), and alanine aminotransferase normalized in 56% of cases (odds ratio (OR) versus. controls, 3.11; 95% confidence interval (CI), 1.56-6.20; p= 0.0013). In multivariate analysis, metformin treatment was associated with higher rates of aminotransferase normalization, after correction for age, gender, basal aminotransferases, and change in body mass index (OR, 5.98; 95% CI, 2.05-17.45). Differences were maintained when the two control groups were separately analyzed. The distribution of positive criteria for the metabolic syndrome was reduced only in the metformin arm (p= 0.001, signed rank test). A control biopsy in 17 metformin-treated cases (14 nonresponders) showed a significant decrease in liver fat (p= 0.0004), necroinflammation, and fibrosis (p= 0.012 for both). No side effects were observed during metformin treatment. CONCLUSIONS: Metformin treatment is better than a prescriptive diet or vitamin E in the therapy of NAFLD patients receiving nutritional counseling. Limited histological data support an association between improved aminotransferases and biopsy findings, which require confirmation in a double-blind trial with appropriate statistical power based on liver histology.

Adult↗
PubMed2005

Mesalamine-induced lung injury in a patient with ulcerative colitis and a confounding autoimmune background: a case report.

Two years after being diagnosed with ulcerative colitis, a 57-year-old man taking oral mesalamine experienced severe respiratory distress due to left lung pleuropneumonitis. Eight months later, severe respiratory distress recurred due to right lung pneumonitis. Extraintestinal manifestations of inflammatory bowel disease or mesalamine-induced pulmonary injury were considered in the differential diagnosis, which was complicated by a history of aseptic meningitis and evidence of an ongoing autoimmune response. The implications of the case are discussed.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

Lack of association between seroprevalence of Helicobacter pylori infection and primary biliary cirrhosis.

AIM: To determine the association between seroprevalence of Helicobacter pylori (H pylori) infection and primary biliary cirrhosis (PBC). METHODS: In this case-control study, 149 consecutive patients (10 males, 139 females, mean age 58.2+/-11 years, range 26-82 years) suffering from PBC and 619 consecutive healthy volunteer blood donors (523 males, 96 females, mean age 47+/-5.3 years, range 18-65 years) attending the Hospital Blood Bank and residing in the same area were recruited. A commercial enzyme linked immunosorbent assay was used to detect anti-H pylori (IgG) antibodies in serum. RESULTS: Antibodies to H pylori were present in 78 (52.3%) out of 149 PBC-patients and in 291 (47%) out of 619 volunteers (P = 0.24, OR 1.24, 95% CI 0.85-1.80). In the subjects less than 60 years old, the prevalence of H pylori infection among PBC-patients (40/79) was slightly higher than in controls (50.6% vs 46.2%) P = 0.46, OR = 1.19, 95% CI: 0.72-1.95). In those over 60 years, the prevalence of H pylori infection was similar between PBC-patients and controls (54.2% vs 57.8%, P = 0.7, OR 0.86, 95% CI 0.36-2.07). CONCLUSION: There is no association between seroprevalence of H pylori infection and primary biliary cirrhosis.

Adult↗
PubMed2004

Peginterferon-alpha2a and ribavirin combination therapy in chronic hepatitis C: a randomized study of treatment duration and ribavirin dose.

BACKGROUND: Treatment with pegylated interferon (peginterferon) and ribavirin for 48 weeks is more effective than conventional interferon and ribavirin in patients with chronic hepatitis C. OBJECTIVE: To assess the efficacy and safety of 24 or 48 weeks of treatment with peginterferon-alpha2a plus a low or standard dose of ribavirin. DESIGN: Randomized, double-blind trial. SETTING: 99 international centers. PATIENTS: 1311 patients with chronic hepatitis C. INTERVENTION: Peginterferon-alpha2a, 180 microg/wk, for 24 or 48 weeks plus a low-dose (800 mg/d) or standard weight-based dose (1000 or 1200 mg/d) of ribavirin. MEASUREMENT: Sustained virologic response: undetectable HCV RNA concentration at the end of treatment and during 12 to 24 weeks of follow-up. RESULTS: Overall and in patients infected with HCV genotype 1, 48 weeks of treatment was statistically superior to 24 weeks and standard-dose ribavirin was statistically superior to low-dose ribavirin. In patients with HCV genotype 1, absolute differences in sustained virologic response rates between 48 and 24 weeks of treatment were 11.2% (95% CI, 3.6% to 18.9%) and 11.9% (CI, 4.7% to 18.9%), respectively, between standard- and low-dose ribavirin. Sustained virologic response rates for peginterferon-alpha2a and standard-dose ribavirin for 48 weeks were 63% (CI, 59% to 68%) overall and 52% (CI, 46% to 58%) in patients with HCV genotype 1. In patients with HCV genotypes 2 or 3, the sustained virologic response rates in the 4 treatment groups were not statistically significantly different. CONCLUSION: Treatment with peginterferon-alpha2a and ribavirin may be individualized by genotype. Patients with HCV genotype 1 require treatment for 48 weeks and a standard dose of ribavirin; those with HCV genotypes 2 or 3 seem to be adequately treated with a low dose of ribavirin for 24 weeks.

Adult↗