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Biomedical subjects

M Rizzetto

Publications and source records attributed to M Rizzetto.

At least 73 records · Page 4Linked to original sources
PubMed2002

Use of arterial conduit as an alternative technique in arterial revascularization during orthotopic liver transplantation.

BACKGROUND: The risk of hepatic artery thrombosis after orthotopic liver transplantation is higher in cases of poor hepatic arterial inflow, small or anomalous recipient hepatic arteries, unsafe native hepatic arteries. AIMS: To assess the use of arterial conduits as alternative technique for graft revascularization. PATIENTS: At the Liver Transplant Center of the "S. Giovanni Battista" Hospital in Torino, a review has been made of 600 consecutive orthotopic liver transplantations in 545 adult patients from 1990 to 1999. METHODS: In 95 orthotopic liver transplantations (15.8%) in 88 patients, the graft was supplied by infrarenal conduit, while in 505 orthotopic liver transplantations (84.2%) in 457 patients, a direct anastomosis was used. RESULTS AND CONCLUSIONS: The overall incidence of hepatic artery thrombosis in our series was 3.5% (21/600): 5.3% (5/91) for conduits and 3.2% (16/505) for standard technique (p=ns, chi2 test). The actuarial 5-year graft survival was 67.7% for conduits and 68.6% for the standard technique; p (log rank): ns. The iliac prosthesis torsion was the only complication related to the use of infrarenal iliac conduit. The arterial conduit, performed with donor iliac artery, is an effective and safe revascularization technique in patients at high risk of arterial thrombosis.

Adolescent↗
PubMed2002

Systemic nitric oxide production and renal function in nonazotemic human cirrhosis: a reappraisal.

OBJECTIVES: Several studies in human cirrhosis have demonstrated increased nitric oxide (NO) production. In experimental animals, intracerebroventricular administration of NO donors causes a marked depression of the endogenous dopaminergic activity, a function known to be physiologically recruited and exerting a natriuretic function in patients with compensated cirrhosis. The aim of this study is to evaluate the interaction between the systemic plasma levels of NO, the endogenous dopaminergic activity and the main parameters of renal function in patients with liver cirrhosis of differing degrees of severity. METHODS: A total of 21 patients (11 with preascitic and 10 with nonazotemic diuretic-free ascitic cirrhosis) and 10 healthy control subjects underwent the following tests: a) basal plasma renin activity (PRA) and aldosterone levels; b) renal clearances of sodium, potassium, inulin, para-minohippurate and lithium (the latter being a measure of the fluid delivery to the distal nephron); c) NO systemic plasma levels measured through paramagnetic resonance spectroscopy as nitrosylhemoglobin complexes; d) endogenous dopaminergic activity, evaluated by means of the incremental prolactin and aldosterone plasma levels after dopaminergic blockade with i.v. metoclopramide. RESULTS: NO plasma values and endogenous dopaminergic activity, although significantly increased with respect to healthy controls, were not different in the two groups of patients. The plasma NO/PRA ratio was significantly higher in the group of compensated patients with respect to ascitic cirrhotics (respectively, 18.3 +/- 11.8 vs 3.5 +/- 2.6 A.U./ng/ml/h, p < 0.001). Compared with compensated cirrhotics, patients with ascites showed significantly lower values of glomerular filtration rate (GFR) and renal plasma flow (RPF). Interestingly, GFR values were substantially the same in the ascitic patients and the control subjects. Compensated patients displayed a significant positive correlation between metoclopramide-induced incremental aldosterone plasma levels (i.e., endogenous dopaminergic tone) and fractional excretion of sodium (r = 0.58; p < 0.05). In the group of compensated patients, NO levels correlated inversely with creatinine plasma concentrations (r = -0.85; p < 0.001) and directly with inulin clearance (r = 0.65; p < 0.05). CONCLUSIONS: These data show that, at least in compensated cirrhotic patients, the stimulation of systemic NO production and the increased dopaminergic function may be mechanisms preventing renal perfusion, GFR, and fractional excretion of sodium from precocious reductions.

Adult↗
PubMed2002

Renal tubular events following passage from the supine to the standing position in patients with compensated liver cirrhosis: loss of tubuloglomerular feedback.

BACKGROUND AND AIMS: Patients with preascitic liver cirrhosis display significant renal sodium retention in the upright posture and an exaggerated natriuresis during recumbency. To date, intrarenal sodium handling in these patients has not been studied using lithium clearance and fractional excretion techniques during recumbency and orthostatism. METHODS: Ten patients with preascitic (Child-Pugh A) liver cirrhosis and 10 healthy subjects underwent the following measurements during recumbency and then after four hours of standing: (a) active renin and aldosterone plasma levels; and (b) renal clearance of creatinine, sodium, potassium, and lithium (an index of fluid delivery to the loop of Henle). RESULTS: Unlike the control group, in the upright posture patients had significantly lower values of lithium clearance and fractional excretion compared with recumbency (21.6 (8.6) v 30.5 (10.2) ml/min (p<0.03) and 12.8 (4.4)% v 20.8 (4.9)% (p<0.01), respectively). Our patients showed maintenance of the glomerular-tubular balance-that is, the correlation between creatinine clearance and proximal tubular reabsorption of fluid-during both recumbency and in the upright posture (r=0.96, p<0.001; r=0.97, p<0.001, respectively). In contrast, patients displayed tubuloglomerular feedback only in the supine position. This was demonstrated by the observation of a negative correlation between lithium fractional excretion (a measure of the fractional delivery of sodium to the distal nephron) and filtered sodium load only in recumbency (r=-0.73; p< 0.03) and not during standing (r=0.22; p> 0.05). CONCLUSIONS: This study suggests that both the reduction in fluid and sodium delivery to the distal nephron and loss of tubuloglomerular feedback (the mechanism increasing glomerular filtration rate when the distal tubule is reached by a reduced sodium load) contribute towards the tendency to sodium retention in compensated cirrhosis during prolonged upright posture.

Adult↗
PubMed2002

Treatment of chronic hepatitis B.

Infection with the hepatitis B virus has switched over the last 20 years from the classical HBeAg positive serologic pattern to a HBeAg negative form that is linked, in the Mediterranean basin, with the epidemiologic replacement of the causative wild-type of virus B with mutant variants, whereby mutations in the core-promoter and in the pre-core region prevent the secretion of HBeAg. The wild-type pattern of infection (characterized by relatively high steady level ALT, high HBV-DNA levels and clinically overt liver disease) responds relatively well to Interferon: 3 to 5 mega units daily or 10 mega units every other day for 16 weeks induce anti-HBe seroconversion, normalize the ALT and possibly also eliminate the HBsAg in some 40% of the adults with a minimal (7%) risk of relapse. However, the mutant type infection (anti-HBe positive / HBe Ag negative) is less responsive to Interferon; this has led to the search for novel nucleoside analogues which has currently culminated in the advent of Lamivudine. This competitor of cytidine is 80% bioavailable and devoid of side-effects at the oral dose of 100 mg daily; tolerance continues for therapies up to 3 years. Lamivudine therapy shares with Interferon a rapid decline of ALT accompanied by improvement of histology; at variance with Interferon there is a delayed accumulating seronconversion to anti-HBe and the switch to anti-HBs is rare. Over the long term its activity is abolished by the emergence of specific viral mutations (YMDD mutants) that rekindle the disease. The indications to Lamivudine therapy in HBeAg negative chronic hepatitis B are currently under investigation. Lamivudine is highly efficacious in preventing HBV reinfection in liver transplants.

Antiviral Agents↗
PubMed2002

Eradication of Helicobacter pylori infection with proton pump inhibitor-based triple therapy. A randomised study.

BACKGROUND: Helicobacter pylori (H. pylori) infection plays an important role in the pathogenesis of duodenal ulcer (DU) disease. Low DU recurrences and reinfection rates were universally described, when treatment was effective. It has been suggested that short-term triple therapy, comprising a proton pump inhibitor plus 2 antibiotics (clarithromycin, amoxycillin or a nitroimidazole), should be used as first choice in treating H. pylori infection. Nevertheless, conflicting results have been reported on using these treatment regimens in different countries. Our aim was to compare cure rates of H. pylori infection, with a 1-week triple therapy versus 10 and 15 day triple schedules, in patients with DU. METHODS: A total of 172 patients (91 males, mean age 56.2+/- 3.2 years) were randomly treated with a triple therapy including a standard dose of proton pump inhibitor, amoxicillin at a dose of 1 g twice daily and clarithromycin 500 mg twice a day. Sixty-six patients received a 1-week triple therapy (group I), 42 subjects were treated with a 10-day triple therapy (group II) and 64 others with a 14-day triple therapy (group III). H. pylori infection at entry and after eradication, at least 4 weeks after therapy had ended, were assessed by 13C urea breath test and histology on biopsies from the antrum and the corpus. RESULTS: At the end of the course of treatment, the overall H. pylori eradication rate was 68.2% (45/66) in group I, 76.2% (32/42) in group II and 71.9% (46/64) in group III, without any statistically significant difference between the 3 differing period regimens, although a trend for better results with the 10-day triple therapy was observed. Compliance was good and side effects infrequent and mild. CONCLUSIONS: None of the 3 periods of triple therapy achieved 80% eradication rate recommended by the Maastricht Consen-sus Conference. The 10-day triple therapy, although not significantly, provided a satisfactory treatment against H. pylori infection.

Adult↗
PubMed2002

Surgery for carcinoma of the gallbladder. Our experience.

BACKGROUND: Carcinoma of the gallbladder is a gastrointestinal malignancy with a very poor prognosis. The 5-year survival rate amounts to less than 5% in most series. In this study we reviewed the results of surgical treatment for gallbladder carcinoma with special reference to extended radical procedures. METHODS: Between 1995 and 2000 we enrolled 36 patients (17 males and 19 females), 24 of whom were treated with simple cholecystectomy and 12 with radical resection (partial hepatectomy, regional lymphadenectomy, and common bile duct resection). The tumours were classified by stage using the criteria of the American Joint Committee on Cancer (AJCC). Stages, operative procedures, results of pathologic examinations and the outcome of the resected cases were reviewed. RESULTS: There were 2 postoperative deaths (0.55%). The mean follow-up period was 19.1 months (range 1-60). For stage I and II disease extended cholecystectomy had a better result than simple cholecystectomy: the 5-year survival rates were 38.4 versus 19%, respectively. For the patients with advanced stage III or IV gallbladder carcinoma, a significant advantage of survival resulted in case of liver resection as compared to surgical treatment without liver resection: the 5-year survival rates were 20 and 0%, respectively. CONCLUSIONS: The survival of stage I-II patients was good. For the patients in higher stages the prognosis was significantly worse. In these cases more aggressive surgery may be needed.

Aged↗
PubMed2002

The role of gastroesophageal reflux disease in chest pain.

Gastroesophageal reflux disease (GERD) is thought to play an important role in the pathogenesis of non-cardiac, unexplained, chest pain. The physiopathological mechanism of this extraesophageal manifestation, remains unclear but it is supposed that the ache could be triggered by the stimulation of acid-sensitive nociceptors of the mucosa. The esophageal origin of the symptom may be identified by an empiric trial of high-dose antisecretory drugs or an abnormal prolonged ambulatory pH monitoring study. Less important is the role of endoscopy especially in subjects without typical symptoms of GERD. The use of manometry or provocative tests can consent to evaluate for esophageal motility abnormalities. It is generally accepted that in clinical practice, in patients with non-cardiac chest pain, the administration of proton pump inhibitors, could serve as a first approach. It is cost-effective in the short-term period, when compared with investigation for gastrointestinal causes, with cost savings persisting beyond a year. In conclusion, patients with non-cardiac chest pain of unknown origin should be carefully screened for the occurrence of GERD, but further research is needed to clarify the role of the latter on the pathogenesis of this symptom.

Chest Pain↗
PubMed2002

Infection by Helicobacter pylori and acute myocardial infarction. Do cytotoxic strains make a difference?

The classical risk factors for acute myocardial infarction (AMI) fail to explain all the epidemiological variations of the disease. Among the risk factors recently reported, several infectious agents appear to increase the risk of AMI. Helicobacter pylori (H. pylori) infection, a bacterium involved in duodenal and gastric ulcer, gastric cancer and MALT-lymphoma, seems to be strongly associated with AMI. More virulent (anti-CagA positive) strains of the bacterium are almost exclusively the causative agents of such diseases. To determine the prevalence of H. pylori infection and of virulent strains, a case-control study was conducted in a group of male patients with AMI. A group of patients consecutively admitted to the Emergency Care Unit served as controls. We studied 223 consecutive male patients, mean age 60.2 (range 40-79) years, admitted for AMI to the Coronary Care Units at Hospitals in two towns of Northern Italy, 223 age matched male patients (mean age 61.8, range 40-79 years) admitted to the Emergency Care Unit, served as control. H. pylori seroprevalence was assessed by presence of antibodies (IgG) against H. pylori and anti-CagA in circulation. Among the patients we investigated the presence of hypertension, levels of cholesterol and glucose in serum, fibrinogen in plasma and smoking habits. H. pylori infection was present in 189/223 (84.7%) of the patients and in 138/223 (61.8%) of the control population (p < 0.0001 OR 3.42 [IC 95% 2.12-5.54]). The anti-CagA antibodies were detected in 33.8% of infected patients with AMI (64/189) versus 26.8% in the control subjects (37/138) (p:0.17, OR 1.40 [IC 95% 0.84-2.33]). Classical risk factors for AMI did not differ among patients with and without H. pylori infection. Patients admitted to the Coronary Care Unit for acute myocardial infarction had a notably higher prevalence of anti-H. pylori not restricted to virulent strains, when compared to a population of patients referred to the Emergency Care Unit. The classical risk factors for coronary disease were present in the patients with AMI irrespective of H. pylori status.

Adult↗
PubMed2002

Extragastric manifestations of Helicobacter species infection. Do these bacteria act as triggers?

Since the latest decade, several studies have reported on the association between chronic Helicobacter pylori (H. pylori) or Helicobacter species (H. species) infection and a variety of extragastric manifestations. These include ischaemic heart disease (IHD), liver diseases, skin diseases, blood disorders and others. However, the hypothesis of an aetiological role has not yet been fully investigated. The epidemiological studies have frequently involved control selection bias, population of small sizes, and presence of confounders, like age and socio-economic conditions. Randomised, long-term and large studies on the follow-up of H. pylori eradication in extragastric diseases are lacking. The present paper attempts to highlight both the epidemiological source of the actual controversies and the biological plausibility for a causal role of H. pylori or H. species infection, in the pathogenesis of some of the most debated extragastric manifestations. Although currently available data do not provide proof of the role of H. pylori infection in the pathogenic mechanism of extragastric diseases, a potential relationship cannot be ruled out. Thus, the need for extensive studies with appropriate epidemiological and clinical approaches is evident.

Journal Article↗
PubMed2002

Decreasing eradicaton rate of Helicobacter pylori infection with metronidazole-based triple therapy. A randomised study.

BACKGROUND: Helicobacter pylori (H. pylori) infection plays an important role in the pathogenesis of duodenal ulcer (DU) disease. Low DU recurrences and reinfection rates were universally described, when treatment was effective. It has been suggested that short-term triple therapy, comprising a proton pump inhibitor plus two antibiotics (clarithromycin, amoxicillin or a nitroimidazole), should be used as first choice in treating H. pylori infection. Nevertheless, conflicting results have been reported on using these treatment regimens in different countries, due to the resistance of H. pylori against one or more antibiotics. Our aim was to compare the efficacy, for H. pylori eradication, of 1-week triple therapy versus 10 and 14-day triple schedules, in patients with a history of recurrent DU. METHODS: A total of 159 patients (85 males, mean age 59.2+/-3.2 years) was randomly treated with a triple therapy including a standard dose of omeprazole twice daily, amoxicillin 1 g twice daily and metronidazole 500 mg twice daily. Fifty-three patients received 1-week triple therapy (Group I), 53 subjects were treated with 10-day triple therapy (Group II) and 53 others with 14-day triple therapy (Group III). H. pylori infection at entry and eradication, at least 4 weeks after therapy had ended, was assessed by 13C urea breath test and histology on biopsies from the antrum and the corpus. RESULTS: Of the 159 subjects randomised into the study, 6 (3 in group II and 3 in group III) were excluded from the per protocol (PP) analysis because of discontinuations. At the end of the course of treatment, the overall H. pylori eradication rate in the intention-to-treat analysis, was 73.5% (39/53) in group I, 71.6% (38/53) in group II and 73.5% (39/53) in group III, without any statistically significant difference. Moreover, the PP analysis also showed no statistical differences, with an eradication rate of 73.5% (39/53) in group I, 76% (38/50) in group II and 78% (39/50) in group III. The reported frequency of side-effects was evenly distributed between the groups, but 6 patients (3.7%) stopped because of adverse events only in groups II and III. CONCLUSIONS: The present study shows that there is no significant difference between the three regimens although the 14-day triple therapy shows a slightly higher H. pylori eradication rate. There is a strong need, in our region, to put forward surveillance programmes to monitor the prevalence of local resistant strains and to guide treatment on the basis of resistance patterns.

Journal Article↗
PubMed2001

Postprandial triglyceride-rich lipoprotein metabolism and insulin sensitivity in nonalcoholic steatohepatitis patients.

Nonalcoholic steatohepatitis (NASH) is a syndrome frequently associated with obesity, diabetes mellitus, and dyslipidemia. Increased fasting insulinemia and blood glucose levels may trigger a reduced catabolism of lipoproteins rich in triglycerides by lipoprotein lipase (LPL) and an increase in their fasting and postprandial levels. An association between postprandial lipemia and coronary heart disease has been observed, and many studies now support this concept. The most important result of our study is the increase in triglyceride-rich lipoproteins response after a fat load in NASH patients, the increase of incremental area under the postprandial curve, and the duration of the hypertriglyceridemic peaks. The persisting postprandial plasma triglyceride elevation in NASH patients was mostly due to the elevated plasma level of large triglyceride-rich particles. These data are coupled with lower plasma HDL2-cholesterol levels. As for lipoprotein analyses, the number of apolipoprotein B100 (ApoB100) particles is not significantly different between the two groups, and the higher content of triglycerides in NASH very low density lipoproteins (VLDL) increases the triglyceride-to-ApoB ratio and the particle size. A decreased enzymatic activity of LPL or a defective assembly and secretion of VLDL from hepatocytes due to a moderate reduction in microsomal triglyceride transfer protein could be involved in the overloading of VLDL. Moreover, the undetectable levels of ApoB48 in triglyceride-rich lipoproteins fraction A could be related to the synthesis of smaller and denser chylomicrons. NASH patients not only are insulin resistant but also tend to present alterations in fatty meal delivery, suggesting that an increase in fasting plasma insulin and glucose, with insulin resistance, joins with depressed metabolism of triglyceride-rich lipoproteins. An increase in postprandial triglyceride levels with production of large VLDL suggests an atherogenic behavior of lipid metabolism, in accordance with the high prevalence of the metabolic syndrome in NASH patients. This paper suggests that a fat load may be useful in early detection of atherogenic risk in the presence of otherwise normal fasting plasma lipids.

Adult↗
PubMed2001

Prevention of hepatitis B virus recurrence after liver transplantation in cirrhotic patients treated with lamivudine and passive immunoprophylaxis.

BACKGROUND/AIMS: Treatment with hepatitis B virus immune globulins (HBIG) or lamivudine has reduced the rate of hepatitis B recurrence after liver transplantation to approximately 50%. METHODS: To further decrease hepatitis B recurrence, 33 hepatitis B virus (HBV)-related cirrhotic patients were treated with lamivudine before liver transplantation and with lamivudine together with low-dose HBIG (46 500 IU the first month followed by 5,000 lU/monthly) after surgery. RESULTS: While on lamivudine, serum HBV DNA level decreased significantly in all patients and in 11 (33%) the Child-Pugh score improved. Twenty-six patients were transplanted. Among the 25 who survived for longer than 12 months, only one (4%) experienced a hepatitis B recurrence over an average follow-up of 31 months, a rate significantly lower (P = 0.0002) than the 50% recurrence rate among a historical control group of 12 patients. However, low-level HBV replication was detected sporadically throughout the follow-up in 64% of patients. CONCLUSIONS: Over the medium-term, combined prophylaxis with lamivudine and HBIG significantly decreases the risk of hepatitis B recurrence after liver transplantation. Though low-level HBV infection recurred in two thirds of patients, the pathogenic expression of HBV was prevented.

Adult↗
PubMed2001

Interferon and amantadine in combination as initial treatment for chronic hepatitis C patients.

BACKGROUND/AIMS: To evaluate the efficacy and tolerance of amantadine in combination with interferon in the treatment of chronic hepatitis C. METHODS: Multi-centre trial including 180 chronic hepatitis C patients without cirrhosis, randomly enrolled to receive interferon 6 MU every other day for 6 months followed by 3 MU for further 6 months (group A, 90 patients), or the same schedule plus amantadine 200 mg/day (group B, 90 patients). Primary end-point was a sustained virological and biochemical response, secondary end-points were on-treatment (third month) and end-of-treatment response rates. RESULTS: The two groups had similar demographic, biochemical and virological characteristics. A sustained response after 6 months follow-up was observed in 17% of group A and 24% of group B patients (P not significant), an end-of-treatment response was observed in 37% in group A and 47% in group B (P not significant), an on-treatment response was observed in 46% in group A and 61% in group B patients (P < 0.05). No major side effects due to amantadine administration were observed. CONCLUSIONS: Adding amantadine to interferon did not improve the sustained treatment efficacy. However, the rate of early response at the third month of therapy was significantly higher in the combination therapy group.

Adult↗