Biomedical subjects

K Cristiano

Publications and source records attributed to K Cristiano.

5 recordsLinked to original sources

PubMed1992

Prevalence of hepatitis C virus antibodies and hepatitis C virus-RNA in an urban population.

Several studies had been carried out on anti-hepatitis C virus (HCV) prevalence in populations with blood exposure risks and in blood donors. New tests are now available which allow the investigation to extend to other parameters such as antibody type and HCV-RNA. In this study the prevalence of anti-HCV c100-3 and the associated epidemiological, clinical, and virological markers were evaluated in subjects from an urban population located in central Italy. In positive cases the time persistence of HCV-RNA and anti-HCV antibody pattern was studied. For this purpose, sera from 1,484 randomly sampled individuals, aged 30-69 years, collected in 1985 and stored at -80 degrees C were retrospectively tested. The prevalence was 0.87% (i.e., 13 anti-HCV c100-3 positive cases). A significant association was observed with raised alanine transaminase (ALT) levels (P less than 0.001). Paired serum samples from 11 out of the 13 subjects collected in 1985 and 1991 were tested by nested polymerase chain reaction (PCR) using primers from the 5' non-coding region and by 4-RIBA. Concordant RIBA patterns between 1985 and 1991 were observed in the majority of positive paired sera (7/9) as well as for HCV-RNA (6/9). HCV-RNA was present in sera simultaneously positive to both types of antibody or to anti-c100-3 or anti-c22 alone. A wide spectrum of viral and antibody patterns in anti-HCV c100-3 positive sera was observed in this urban population and persisted for at least 6 years.

Adult↗

PubMed1992

Hepatitis C viral RNA in serum of patients with chronic non-A, non-B hepatitis: detection by the polymerase chain reaction using multiple primer sets.

The recently introduced antibody test for hepatitis C virus (HCV) infection has proven to have certain limitations. Since HCV itself is usually present in clinical specimens at very low titers, a useful assay for the virus must have very high sensitivity. We have developed a simple, highly sensitive assay for HCV RNA based on the polymerase chain reaction (PCR). In this test, RNA extracted from HCV infected serum or plasma is used as the template for double PCR with nested primers. Sensitivity studies demonstrate that this assay is able to detect HCV at or beyond the sensitivity level of chimpanzee infectivity. We tested, with several sets of nested primers, 40 patients with chronic non-A, non-B hepatitis (36 seropositive and 4 seronegative) and found that 35/40 were PCR positive including all 4 seronegative patients. Normal human plasma and plasma from hepatitis B infected patients did not react in this test. This assay has proven to be valuable for determining the presence of HCV in various samples; furthermore, it offers the possibility of diagnosis of HCV infection in seronegative patients.

Adult↗

PubMed1991

Decrease in serum hepatitis C viral RNA during alpha-interferon therapy for chronic hepatitis C.

OBJECTIVE: To assess the effect of alpha-interferon therapy on hepatitis C viral RNA in serum of patients with chronic hepatitis C. DESIGN: Retrospective testing for hepatitis C viral (HCV) RNA and antibody to the hepatitis C virus (anti-HCV) of stored serum samples from a randomized, double-blind, placebo-controlled trial of alpha-interferon therapy. SETTING: Warren Grant Magnuson Clinical Center of the National Institutes of Health, a tertiary referral center. PATIENTS: Forty-one patients with chronic non-A, non-B hepatitis were entered in this trial. INTERVENTIONS: Twenty-one patients were treated with alpha-interferon, and 20 patients were treated with placebo for 6 months. Seventeen placebo recipients were then treated with alpha-interferon for up to 1 year. METHODS: Samples were tested for anti-HCV by enzyme-linked immunosorbent assay. Hepatitis C viral RNA was detected in serum using the polymerase chain reaction. Titers of both antibody and RNA were determined by serial end-point dilution. MAIN RESULTS: At entry into the trial, 37 (90%) of 41 patients had anti-HCV and 39 (95%) had HCV RNA in serum. Anti-HCV titers decreased slightly with treatment. Serum levels of HCV RNA decreased in all patients who responded to alpha-interferon therapy with improvements in serum aminotransferases; in 17 of 21 responders (81%; 95% Cl, 58% to 95%) HCV RNA became undetectable. In contrast, in only 2 of 16 (12%; Cl, 2% to 38%) patients who did not respond to treatment did HCV RNA become undetectable. In 19 patients treated during the preliminary 6-month period with placebo, HCV RNA remained detectable. Finally, in the 11 patients who relapsed when treatment was stopped, HCV RNA reappeared in the serum, but in 4 of 7 patients with a sustained improvement in serum aminotransferases, HCV RNA remained undetectable. CONCLUSIONS: These results indicate that the clinical and serum biochemical response to alpha-interferon in chronic hepatitis C is associated with a loss of detectable HCV genome from serum.

Base Sequence↗

PubMed1991

Hepatitis C viral RNA in serum of patients with chronic non-A, non-B hepatitis: detection by the polymerase chain reaction using multiple primer sets.

The recently introduced antibody test for hepatitis C virus infection has already proved to be valuable in many situations such as screening blood donors and diagnosing chronically infected patients, but this antibody assay has certain limitations. Hepatitis C virus itself is usually present in clinical specimens at very low titers; therefore a useful assay for the virus must have very high sensitivity. We have developed a simple, highly sensitive assay for hepatitis C virus RNA based on the polymerase chain reaction. In this test RNA extracted from hepatitis C virus-infected serum or plasma is used as the template for double polymerase chain reaction with nested primers. Sensitivity studies demonstrate that this assay is able to detect hepatitis C virus at or beyond the sensitivity level of chimpanzee infectivity. Preliminary studies in chronic non-A, non-B hepatitis showed that 16 of 36 patients positive for antibody to hepatitis C virus and 2 of 4 patients negative for antibody to hepatitis C virus were positive in the polymerase chain reaction test. By retesting the polymerase chain reaction-negative patients with several sets of polymerase chain reaction primers, we found hepatitis C virus RNA in 35 of the 40 patients including all 4 seronegative patients. Normal human plasma and plasma from patients with hepatitis B infection did not react in this test. This assay has proved to be valuable for determining the presence of hepatitis C virus RNA in various samples. Furthermore, it offers the possibility of diagnosis of hepatitis C virus infection in patients who do not react in the presently available antibody tests.

Animals↗

PubMed1989

Co-amplification of multiple regions of the HIV-1 genome by the polymerase chain reaction: potential use in multiple diagnosis.

We have used the polymerase chain reaction (PCR) to detect by co-amplification, multiple regions of the HIV-1 genome in infected cells. Genomic RNA and DNA from productively infected H9 cells were independently extracted and amplified in reactions with and without reverse transcriptase respectively using primer pairs to the gag, env, tat and nef regions of the viral genome in the same reaction mixture. PCR-products were analysed by liquid hybridization with end labelled oligonucleotide probes followed by gel-electrophoresis (oligomer hybridization). The primer pairs were capable of detecting as few as 10 copies of RNA and 10-20 copies of integrated proviral DNA. The ability to co-amplify multiple target regions in the same incubation mixture provides a method for detecting and confirming the presence of HIV-1 in samples for which limited nucleic acid is available. In addition, in reconstitution experiments, the same method was used to detect HIV-1 and HTLV-I simultaneously with comparable sensitivity (20-40 gene copies each). This offers the possibility of simultaneous diagnosis of multiple viral infections, such as those that occur in AIDS, on the same sample preparation.

DNA, Viral↗