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Biomedical subjects

A Smedile

Publications and source records attributed to A Smedile.

At least 55 records · Page 3Linked to original sources
PubMed1994

Advances in hepatitis D virus biology and disease.

Studies over the last decade have defined the natural history and diagnostic features of hepatitis D. Whereas hepatitis D encompasses a wide spectrum of clinical manifestations, patients usually have severe and progressive liver disease. In areas of high endemicity such as Italy, hepatitis D accounts for a significant proportion of requests for liver transplantation. Research interest is now focused on the underlying mechanisms of HDV pathogenesis and identification of the specific interactions of HDV/HBV/host that influence the clinical outcome. Much has been learned about the virology of HDV and its interactions with its helper, HBV. However, little is known about the host response to HDV infection and whether certain immune responses to HDV gene products can modulate the disease course, although there has been some evidence in an animal model that this might be the case. The unique characteristics of HDV replication, eg, autocatalytic self-cleavage and editing of the viral RNA, may influence the disease course and the heterogeneity of HDV genome sequence found in various geographic settings may in part account for the spectrum of disease outcomes by influencing the efficiency of any number of complex interactions. Fortunately, in vitro and in vivo experimental systems are available to address many of these issues and, indeed, further research may identify specific and novel targets for therapeutic intervention. Current medical therapy for hepatitis D is unsatisfactory. The only drug of proven benefit, recombinant interferon, brings relief to only a small proportion of hepatitis D patients. Other antiviral drugs have failed in clinical trials, although studies with some drugs are currently in progress. Fortunately, liver transplantation provides a valid option, because HDV reinfection of the graft occurs much less frequently than does HBV reinfection of HBV transplants and can be adequately prevented by the administration of anti-HBs immunoglobulin. Because of the critical contribution of HBV to the life cycle of HDV, universal immunization against HBV infection represents the ultimate solution for the eradication of hepatitis D. Mass vaccination for HBV and other public health measures for the control of blood-borne pathogens have already resulted in a dramatic decrease in hepatitis D in Italy.

Antigens, Viral↗
PubMed1993

Accumulation of a cellular protein bearing c-myc-like antigenicity in hepatic and non-hepatic delta antigen expressing cells.

Patients with chronic but not acute hepatitis delta virus infection undergo a strong accumulation of a protein of cellular origin which specifically reacts with a panel of anti-c-myc antibodies and which is expressed in the same nuclei that express the delta antigen. In this paper we report on the in vitro characterization of this phenomenon. The delta antigen induced c-myc antigen accumulation can occur in vitro upon transfection of HBsAg positive and negative cell lines with HDAg expression vectors. Using recombinant vaccinia viruses expressing only p24 or p27 we demonstrate that structures common to the two isoforms of HDAg are responsible for the phenomenon, which is not restricted to cells of hepatic origin.

Antigens, Viral↗
PubMed1992

Orthotopic liver transplantation for chronic viral hepatitis: an overview.

The aim of this review is to discuss the problem of orthotopic liver transplantation in patients suffering from chronic viral liver disease due to hepatitis B, C and D viruses. The decision to operate these patients is often controversial, as the risk of a recurrence of viral infection is very high and reinfection may be severe enough to require a second or even multiple grafts. However, the quality of life and the survival rate improve after transplantation in chronic viral hepatitis patients.

Chronic Disease↗
PubMed1991

Adenine arabinoside monophosphate and acyclovir monophosphate coupled to lactosaminated albumin reduce woodchuck hepatitis virus viremia at doses lower than do the unconjugated drugs.

The woodchuck was selected to study the efficacy of liver-targeted antiviral drugs on hepadnavirus replication. Nineteen woodchucks chronically infected with woodchuck hepatitis virus were treated with adenine arabinoside monophosphate or acyclovir monophosphate, either free or conjugated with the liver-targeting molecule lactosaminated human serum albumin. Circulating woodchuck hepatitis virus DNA levels remained unchanged in untreated animals and in those receiving the carrier lactosaminated human serum albumin alone; in contrast, they were consistently lower after 5 days of treatment with the antiviral drugs. Free and conjugated adenine arabinoside monophosphate were active at doses of 10 and 0.75 mg/kg, respectively, and free and coupled ACVMP were active at doses of 20 and 2.6 mg/kg, respectively. These results indicate that the dosages of adenine arabinoside monophosphate and acyclovir monophosphate required to inhibit hepadnavirus growth can be sharply reduced by coupling the drugs to lactosaminated human serum albumin.

Acyclovir↗
PubMed1991

Patterns of hepatitis delta virus reinfection and disease in liver transplantation.

Twenty-seven carriers of the hepatitis B surface antigen who underwent liver transplantation in Italy and Belgium for terminal Hepatitis delta virus (HDV) cirrhosis were investigated. In 22 of the patients, HDV infection recurred. Two patients died of coexisting HDV and hepatitis B virus (HBV) reactivation. Four patients who died of unrelated causes were found to have HDV without signs of HBV reactivation. Five patients (18%) cleared both HBV and HDV after transplantation with no evidence of hepatitis (mean follow-up, 29 months). In many surviving patients. HDV infection recurred early without signs of HBV reactivation. Disease returned in the 11 HDV-infected patients in whom HBV also recurred. Histological hepatitis did not recur during an interim of 12-33 months in the 5 HDV-infected patients in whom HBV did not return. The overall medium-term survival in patients with HDV who underwent transplantation was 77.7%. Liver transplantation offers patients with HDV a hope of cure from disease despite a high risk of reinfection. In the transplantation setting. HDV can cause subclinical infections without any apparent assistance from HBV; these infections become symptomatic only if and when HBV reactivates. Thus, HDV may not be in itself pathogenic but requires cooperation from HBV to cause the appearance of the disease.

Adolescent↗
PubMed1991

Rabbit-derived anti-HD antibodies for HDAg immunoblotting.

We studied the sensitivity and specificity of two rabbit-derived antibodies (W2 and W3) raised against two synthetic peptides of the HDAg: the C-terminus of the p24 protein (W2) and the C-terminus of the p27 protein (W3) (Chiron Co., Emeryville, CA, U.S.A.). The results were compared with those obtained with a human polyclonal anti-HD (W1). We have tested W2 and W3 against blotted serum samples from 25 patients (20 HBsAg positive anti-HD positive, three HBsAg positive anti-HD negative and two HBsAg negative anti-HD negative) and liver extracts from five HBsAg seropositive patients, two anti-HD positive and three anti-HD negative. In serum samples W3 sporadically reacted with a p31 protein present in both anti-HD positive and negative sera; W2 identified the p24 protein in 7/10 W1 positive samples but in none of 10 W1 negative; the p27 protein was captured by W2 only in one highly viremic serum. In every sample of liver extract W3 recognized a 48-kDa band. W1 and W2 stained 5 bands at 45, 27, 24, 16 and 12 kDa. The p45, p27 and p24 proteins were peculiar of HDV-infected livers; p16 and p12 were also detected in HDV free livers. W2 identified an additional 54-kDa protein in 4/5 liver extracts. For diagnostic purposes human polyclonal anti-HD represents the most sensitive probe for HDAg immunoblotting, with a specificity similar to that of rabbit-derived antibodies. The affinity of W2 and W3 antibodies for serum and liver HDAg appears to be lower than for HDAg recombinant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Serological diagnosis of hepatitis B and delta virus (HBV/HDV) coinfection.

Diagnosis of acute hepatitis B virus/hepatitis delta virus (HBV/HDV) coinfection is currently based on detection of anti-HD, however this antibody may be undetectable during the acute phase of hepatitis. To evaluate the entity of misdiagnosis of HBV/HDV coinfection in acute HBsAg-anti-HBc IgM positive hepatitis we examined sera from 245 consecutive patients obtained at admission and day 30, 60, 120, 210 and 400 of their follow-up. Anti-HD was detected in the serum of 26 out of 245 patients (10.6%). In 15% of cases it was present at admission, while in 92% it was found after 30 days. The combined detection of HDV-RNA, HDAg and IgM anti-HD in acute phase sera allowed a correct etiologic diagnosis in 69% of the cases. These findings suggest that the prevalence of HBV/HDV coinfection is underestimated when anti-HD is the only marker to be detected during the acute phase of disease. A correct etiologic diagnosis can only be made by testing acute phase sera for all the available markers of HDV. However, the best cost-effective procedure is to test any patient with HBV markers at presentation for anti-HD, 30-40 days after the onset of symptoms.

Adult↗
PubMed1991

Hepatitis B virus replication modulates pathogenesis of hepatitis D virus in chronic hepatitis D.

Hepatitis D virus and hepatitis B virus nucleic acids were detected by Northern and Southern blot hybridization in the sera and livers of 85 chronic carriers of HBsAg and anti-hepatitis D followed up for a mean of 10 yr. We identified three subsets of patients: 13 with hepatitis D virus and hepatitis B virus viremia, 53 with serum hepatitis D virus RNA, but without hepatitis B virus DNA and 19 negative for both nucleic acids. Genomic and subgenomic forms of hepatitis D virus RNA were detected only in patients with hepatitis D virus and hepatitis B virus viremia. Histological findings and disease activity at admission were comparable in the three groups of patients, but the outcome was significantly worse in patients with active replication of both viruses; two of them died of terminal liver failure and hepatocellular carcinoma developed in two; the remaining patients had an uneventful course. These results suggest that active hepatitis B virus replication represents an important previously unrecognized determinant of severe liver damage in patients with chronic hepatitis D virus infection. Since hepatitis B virus provides the means for hepatitis D virus secretion and release from infected cells, active hepatitis B virus multiplication favoring the spread of hepatitis D virus from cell to cell may increase the pathogenetic potential of the defective agent.

Adolescent↗