Search PubMed⌕ Search

Biomedical subjects

A Ponzetto

Publications and source records attributed to A Ponzetto.

At least 55 records · Page 3Linked to original sources
PubMed1997

Gastric B-cell clonal expansion and Helicobacter pylori infection in patients with autoimmune diseases and with dyspepsia. A follow-up study.

BACKGROUND: It is not clear whether gastric B-cell clonal expansion, a possible precursor of mucosa-associated lymphatic tissue (MALT) lymphoma, is exclusively linked to Helicobacter pylori infection and virulence. METHODS: In this study we followed up, for up to 33 months, 16 VDJ polymerase chain reaction-positive patients (4 with dyspepsia, 9 with Sjögren's syndrome, and 3 with other autoimmune diseases). Of these, 12 were H. pylori-positive. In addition, in H. pylori-positive patients we tested whether the serum anti-cag-A (a potential marker of virulence) was preferentially associated with B-cell clonality. RESULTS: In all but one patient clonality appeared temporally unrelated to H. pylori infection. The prevalence of anti-cagA was not higher in H. pylori/VDJ-positive patients than in controls. CONCLUSIONS: These data indicate that, in addition to H. pylori, gastric B-cell clonality may be sustained by other agents/mechanisms. Anti-cag-A does not appear to be involved in the pathogenesis of clonality.

Adult↗
PubMed1997

[Recurring duodenal ulcer. Evaluation of previous complications as a predictive factor of ulcer recurrence after eradication of Helicobacter pylori].

Duodenal ulcer is a chronic disease, punctuated by acute relapses. The pathogenic mechanism in 90-100% of cases is infection by Helicobacter pylori. Two major strains exist of this bacterium: I strain, which secretes a vacuolating cytotoxin (Vac-A), and another protein named cytotoxin-associated (Cag-A) and type II strain, unable to produce both proteins and unable to produce duodenal pathology. We sought to identify the natural history of relapsing duodenal ulcer after cure of the bacterial infection. In particular, we followed the outcome of patients who repeatedly had bled from their recurrent ulcer disease, after success in eliminating the microorganism from the stomach. None of 12 repeated bleeders had an ulcer recurrence after the cure of Helicobacter pylori infection. Only 3 (5%) of 60 frequent relapser had a new episode of duodenal ulcer during a follow-up reinfection by Helicobacter pylori. We demonstrated that the cure of bacterial infection is also the cure of duodenal ulcer recurrence, but for a few cases, in the latter, event one could hypothesize a defect in the production of growth factors (Epidermal Growth Factor, Fibroblast Growth Factor) or of cellular polyamines synthesis. It is important to improve the diagnosis of reinfection by implementing the urea breath test.

English Abstract↗
PubMed1997

Family treatment of symptomatic children with Helicobacter pylori infection.

BACKGROUND: Familial clustering of Helicobacter pylori infection has been reported. We tested the hypothesis that simultaneously treating all Helicobacter pylori positive family contacts of infected symptomatic children results in lower treatment failure. METHODS: Relatives of 47 children (index) with Helicobacter pylori gastritis had endoscopy to assess prevalence of infection in first degree cohabiting relatives. Controls included 60 children with dyspepsia and Helicobacter pylori gastritis whose infected family contacts were not treated. Index children, siblings younger than 18 years of age and control children received a 2-week course of amoxicillin and tinidazole. Parents of index children and their siblings over 18 years of age received a 2-week course of Colloidal Bismuth Subcytrate and tinidazole. The eradication rate in index children and their relatives was compared to controls whose infected family contacts were not treated. RESULTS: Helicobacter pylori was found in 67% of 31 siblings younger than 18, in 82% of 22 siblings older than 18 years, and in 87% of 92 parents. Endoscopy, repeated four to six weeks after the end of treatment, showed Helicobacter pylori eradication in 94% of children and siblings younger than 18, and in 70% of parents and siblings over 18 years in the family treatment group, compared with 75% of control children (p < .01). CONCLUSIONS: The high prevalence of the infection in family members suggests that person-to-person spread of Helicobacter pylori takes place. Furthermore our results show that if (or when) required, simultaneous treatment given to the whole family results in lower treatment failure, since it may promote compliance to treatment.

Adolescent↗
PubMed1996

Adenine arabinoside monophosphate coupled to lactosaminated human albumin administered for 4 weeks in patients with chronic type B hepatitis decreased viremia without producing significant side effects.

A conjugate of adenine arabinoside monophosphate (ara-AMP) with the liver-targeting molecule lactosaminated human serum albumin (L-HSA) was administered by intravenous infusion for 28 days to eight patients with chronic type B hepatitis. The daily dose varied among the patients, ranging from 34 mg/kg to 53 mg/kg (equal to 1.5 and 2.3 mg/kg ara-AMP, respectively). Pharmacokinetic analysis indicated that, at every dose tested, the conjugate was disposed of without accumulation. Viral DNA serum levels fell markedly during treatment; values rose again when treatment was ceased. The L-HSA-ara-AMP conjugate did not cause either the neurotoxic side effects of free ara-AMP or other adverse clinical reactions. It produced a significant increase both in serum alkaline phosphatase activity and platelet number, and a small but significant decrease in erythrocyte number. These laboratory parameters returned to normal levels within 2 months after treatment. The conjugate induced the production of small amounts of antibodies (approximately 20 pmol of conjugate bound by 1 mL of serum) in one patient only. In conclusion, the present results indicate that the L-HSA-ara-AMP conjugate can exert the antiviral activity of ara-AMP in chronic type B hepatitis patients without producing the neurotoxic side effects which hamper a 4-week period of treatment with the free drug.

Adult↗
PubMed1996

Liver hepatocyte growth factor does not always correlate with hepatocellular proliferation in human liver lesions: its specific receptor c-met does.

Increased levels of expression of hepatocyte growth factor (HGF) and its specific receptor c-met have been shown in the liver of several benign and malignant pathologies, both in experimental models and humans. We investigated by immunohistochemistry the presence of both HGF and c-met protoocogene product (c-met pp) in 20 hepatocellular carcinomas (HCCs), 5 focal nodular hyperplasias (FNHs), 4 cases of fulminant hepatitis (FH), and 1 case of regenerated liver. The c-met protooncogene product was expressed in all cases with marked overexpression in the HCCs and in ductular metaplasia. HGF was detected in the Ito cells of all cases and in neoplastic hepatocytes of 9 of 20 HCCs (45%). The proliferative index of each lesion was evaluated by means of the polyclonal antibody anti-cyclin A. When the level of expression of HGF and c-met protooncogene product with the percentage of cyclin A+ nuclei were compared, the closest relationship was between c-met protooncogene product and cyclin A+ nuclei were compared, the closest relationship was between c-met protooncogene product and cyclin A. In 11 of 20 HCCs (55%), there wa no correlation between HGF positivity and cyclin A. This seems to suggest that, independently of the levels of native liver HGF, c-met protooncogene product is the most active modulator of liver cell proliferation.

Biomarkers↗
PubMed1996

Histogenesis of primary liver carcinomas: strengths and weaknesses of cytokeratin profile and albumin mRNA detection.

To assess the utility of cytokeratin (CK) profile and albumin mRNA detection (as revealed by in situ hybridization) in the differential diagnosis of primary liver carcinomas (PLCs) we evaluated a series of surgically resected PLCs, comprising 20 "pure" hepatocellular carcinomas (HCCs) (10 well-differentiated, 10 poorly differentiated), 15 cholangiocarcinomas (CCs) (6 peripheral, 5 hilar, and 4 major duct ones) and 10 hepatocholangio-carcinomas (HCC-CCs). 11 of 20 (55%) of the pure HCCs expressed CKs of pure hepatocytic lineage (CK 8 and CK 18); 2 of 10 (20%) of the HCC-CCs displayed only hepatocytic profile, whereas 12 of 15 (80%) of the CCs evidenced mature bile duct cell phenotype (CK 8, CK 18, CK 7, CK 19). All HCCs expressed varying distributions of albumin mRNA, whereas 4 of 6 (67%) peripheral CCs showed cells with focal positivity for albumin mRNA. This suggests that the phenotypic expression of PLC cells are often not fixed, and in particular: (1) peripheral CCs have a different phenotype from hilar and large duct ones; (2) the CK profile and albumin mRNA expression in peripheral CCs show many similarities with those of some HCCs. Furthermore, the results show that a mixed biological phenotype (ie, CK 8, CK 18 and CK 7 and/or CK 19) can be found both among morphologically pure HCCs and peripheral CCs, suggesting that these two forms could share a common histogenesis. We think that special attention should be given to cases in which CK profile and albumin mRNA reveal mixed phenotype, as these tumors could have different biological behavior and respond differently to therapy.

Aged↗
PubMed1996

Treatment of woodchuck hepatitis virus infection in vivo with 2', -3'-dideoxycytidine (ddC) and 2',-3'-dideoxycytidine monophosphate coupled to lactosaminated human serum albumin (L-HSA ddCMP).

Dideoxycytidine (ddC) is a nucleoside analogue active against human immunodeficiency virus and with in vitro activity against human hepatitis B virus. We investigated the ability of ddC to inhibit one of the Hepadnaviridae, the woodchuck hepatitis virus and compared the results with the effect obtained by a conjugate of lactosaminated human serum albumin 2',-3'-dideoxycytidine monophosphate (L-HSA ddCMP). This compound specifically enters the hepatocyte via the asialoglycoprotein receptor. We treated five chronic woodchuck hepatitis virus carriers with intravenous injections of 0.5 mg/kg body weight of ddC for 5 consecutive days, and under the same protocol five woodchucks with 10.4 mg/ kg L-HSA ddCMP, a dose equivalent to 0.25 mg/kg of free ddC. A reduction of serum woodchuck hepatitis virus DNA (5-125 fold) was observed during therapy in three out of five animals receiving ddC and in two of the five animals treated with L-HSA ddCMP. In responding woodchucks, virus DNA levels rebounded immediately after stopping therapy. No signs of toxicity were observed during or after the course of therapy. These preliminary results of short-term treatment indicate that ddC has anti-viral activity against woodchuck hepatitis virus. When the dose was reduced by 50%, L-HSA ddCMP showed anti-viral activity to an even lesser degree.

Animals↗
PubMed1995

Hepatotoxicity of intravenous cyclosporin A in patients with acute ulcerative colitis on total parenteral nutrition.

A group of 24 patients underwent a 7-14-day course of continuously infused Cyclosporin A (2 mg.kg-1.day-1) to treat a severe attack of ulcerative colitis. In 19 of them, including eight treated with total parenteral nutrition, we retrospectively analyzed the serum aminotransferase (AST/ALT) levels at the beginning and at the end of Cyclosporin infusion. The baseline levels of AST/ALT in the group were 19.9 +/- 3.2 and 31.4 +/- 6.4; on stopping Cyclosporin infusion, they were 43 +/- 15.8 and 119 +/- 56, respectively. Six patients showed an ALT change above 1.5 times the upper limit of reference. They included five of the eight patients treated with total parenteral nutrition (62.5%). In one of six, ALT rose to 1000 U/l and was accompanied by full-blown febrile cholangitis (proven by liver biopsy). This episode was preceded by excessive accumulation of Cyclosporin in blood. The development of liver toxicity was independent of the length of Cyclosporin treatment, nor did it impair drug efficacy. Thus, in these patients total parenteral nutrition and Cyclosporin were synergistic, causing twice the frequency of liver damage (62.5%) reported for ulcerative colitis patients on total parenteral nutrition alone (37%). Total parenteral nutrition should not be used to support patients needing Cyclosporin for autoimmune disease. However, too high a dose of Cyclosporin may cause liver disease per se.

Acute Disease↗
PubMed1995

Overexpression of c-met protooncogene product and raised Ki67 index in hepatocellular carcinomas with respect to benign liver conditions.

The c-met protooncogene encodes a 190-kd transmembrane tyrosine kinase. This molecule is the receptor for the hepatocyte growth factor (HGF), which is an important mitogen for hepatocytes both in vitro and in vivo. In experimental models, the c-met transcripts appeared strongly expressed by actively proliferating oval cells (OCs). We evaluated the phenotypic modulation of the c-met protooncogene product (c-met pp), in 10 hepatocellular carcinomas (HCCs), 5 focal nodular hyperplasias (FNHs), 4 cases of fulminant hepatitis (FH), and 1 regenerated liver, selected to include the different biological states of hepatocyte (mature normal hepatocytes, transformed ones, and OCs). The supposed mitogenic effect of HGF was analyzed by comparing c-met pp overexpression with the Ki67 index, whereas anti-OV-6 antibody was used for comparison with the presence of OCs. The anti-c-met pp showed a typical plasma membrane-specific staining in all cases. The signal was much stronger in the HCCs than in the benign conditions. The anti-OV-6 monoclonal antibody showed positive immunostaining in many of the cells expressing c-met pp. The percentage of Ki67+ nuclei in high-grade HCCs paralleled c-met protooncogene overexpression. The c-met pp in OV-6+ cells suggests that the paracrine mechanism postulated in experimental models could also apply to human liver.

Biomarkers, Tumor↗
PubMed1995

Liver targeting of adenine arabinoside monophosphate (ara-AMP) by coupling to lactosaminated human serum albumin.

Adenine arabinoside monophosphate (ara-AMP) is a potent antiviral agent against hepadnaviruses but its use in the treatment of chronic hepatitis B is hampered by severe neurotoxic side effects, which are dose dependent. In order to reduce these adverse reactions and to adopt the lysosomotropic approach to antiviral chemotherapy, ara-AMP was coupled to lactosaminated human serum albumin (L-HSA), a neoglycoprotein which specifically penetrates hepatocytes. In mice with Ectromelia virus hepatitis, ara-AMP coupled with L-HSA was selectively delivered to liver cells in which it was released in a pharmacologically active form. Moreover in woodchucks with WHV hepatitis and in patients with chronic HBV infection, coupled ara-AMP inhibited hepadnavirus replication at a dose (1.5 mg/kg/day) 3-6 times lower than the free drug. A clinical study using a 28-day period of treatment with conjugated ara-AMP at 1.5 mg/kg/day has now been started. In the first 6 patients the treatment has been completed. The conjugate inhibited virus growth without producing any side effects. L-HSA-ara-AMP conjugate must be given by intravenous infusion. New hepatotropic conjugates of ara-AMP have been recently prepared which could be administered by bolus intravenous injection or by intramuscular route. These complexes might assure a better compliance in patients with hepatitis B virus infection for a long lasting liver targeted antiviral treatment.

Amino Sugars↗
PubMed1993

Susceptibility of human liver cell cultures to hepatitis C virus infection.

To develop a cell culture system susceptible to infection by hepatitis C virus (HCV), human fetal hepatocytes, grown in serum-free medium, were inoculated with serum samples from two HCV-infected patients. Viral RNA sequences were detected by polymerase chain reaction, using primers specific for the 5' noncoding region of HCV, in extracts prepared from the hepatocyte cultures as early as 5 days after inoculation. Virus was also released from the infected cells into the medium. The HCV strains could be serially passaged three times into fresh liver cell cultures using intracellular virus as inoculum. Evidence that HCV replication really took place in primary human fetal hepatocytes was also obtained by detection of minus-strand viral RNA (replication intermediate) in cell extracts and of viral antigens in the infected cells.

Base Sequence↗