Biomedical subjects

D Bresters

Publications and source records attributed to D Bresters.

8 recordsLinked to original sources

PubMed1992

Sensitivity of an anti-HCV core peptide ELISA.

A newly developed antibody assay based on a synthetic peptide of 15 amino acids derived from the core region of the hepatitis C virus (HCV) genome was evaluated in serum and plasma panels of (A) 225 haemophiliacs and (B) 44 patients with chronic non-A, non-B (NANB) hepatitis, and in (C) sequential serum samples of 9 patients with transfusion transmitted HCV infection. The new anti-core peptide ELISA was compared with the anti-C100 ELISA. For confirmation of HCV infection, samples were tested in a 4-antigen recombinant immunoblot assay (4-RIBA) and samples of panels B and C were also assayed in cDNA-polymerase chain reaction (PCR). In two panels with a high prevalence of HCV infection (88.4 and 70.5% in haemophilia and NANB hepatitis patients, respectively), the sensitivity of the anti-core peptide ELISA did not differ significantly from the sensitivity of the anti-C100 ELISA. The sensitivity of the new assay as compared with the anti-C100 assay was found to be 0.84 [95% confidence interval (CI): 0.78-0.89] versus 0.92 (95% CI: 0.87-0.95) in haemophilia patients and 0.71 (95% CI: 0.52-0.86) versus 0.84 (95% CI: 0.66-0.95) in NANB hepatitis patients. In sequential serum samples of patients with transfusion-transmitted HCV infection antibodies to the core peptide (in 6/9 patients) appeared later than antibodies to C100 (in 7/9 patients): 168 (range: 70-322) and 143 (range: 59-365) days after transfusion, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed1992

Detection of hepatitis C viral RNA sequences in fresh and paraffin-embedded liver biopsy specimens of non-A, non-B hepatitis patients.

In this study methods of HCV-RNA detection in fresh frozen and formalin-fixed, paraffin-embedded liver biopsies are described. Of 22 untreated chronic non-A, non-B hepatitis patients and 6 control patients, a plasma sample and part of a liver biopsy were freshly frozen for hepatitis C virus (HCV) cDNA-PCR. From 16 of the same non-A, non-B hepatitis patients and from 5 of the same control patients formalin-fixed, paraffin-embedded liver tissue from the same biopsy was available also for HCV cDNA-PCR. In 13 of 22 non-A, non-B hepatitis patients HCV-RNA could be detected in plasma as well as in liver tissue. In the other 9 non-A, non-B hepatitis patients and in 6 control patients, no HCV-RNA was detectable in either plasma or liver tissue. The comparison between HCV cDNA-PCR results in fresh frozen versus formalin-fixed, paraffin-embedded liver biopsies showed that although detection of HCV-RNA in both correlated 100% the quantity of HCV-RNA was lower in the formalin-fixed, paraffin-embedded liver biopsies of 5 of 8 patients for whom end-point dilution titration of liver RNA was performed. We conclude that using the procedures described HCV-RNA can be reliably detected in both fresh-frozen and formalin-fixed, paraffin-embedded liver biopsies and that HCV cDNA-PCR in liver tissue may become an important assay, especially for monitoring anti-viral therapy.

Biopsy↗

PubMed1992

Early antihepatitis C virus response with second-generation C200/C22 ELISA.

Detection of early antibody to hepatitis C virus (HCV) by a new second-generation C200/C22 anti-HCV enzyme-linked immunosorbent assay (ELISA) and a four-antigen recombinant immunoblot assay (4-RIBA) was compared with the first-generation anti-HCV C100 ELISA using sequential serum samples of 9 recipients who were infected with HCV, as detected by polymerase chain reaction after transfusion of blood products. Within 26 weeks after transfusion, 9/9 (100%) recipients seroconverted with C200/22 ELISA, and 6/9 (67%) seroconverted with C100 ELISA. Compared with C100 ELISA, C200/C22 ELISA seroconversion occurred simultaneously in 3 cases, 5-6 weeks earlier in 3 other cases, and 20 weeks earlier in 1 case. Seven of 9 (78%) recipients became positive, and 2/9 (22%) became indeterminate with 4-RIBA. In 8 cases with clinical posttransfusion hepatitis non-A, non-B (PTH-NANB), anti-HCV C200/C22 ELISA seroconversion occurred 2-17 (mean 6) weeks after the onset of hepatitis. In 6 cases of PTH-NANB, anti-HCV C100 ELISA seroconversion occurred 2-26 (mean 9) weeks after the onset of hepatitis. It is concluded that the second-generation C200/C22 ELISA is more sensitive than the C100 ELISA for the detection of antibody during early HCV infection. Indeterminate 4-RIBA results are found in the early phase of HCV infection.

Enzyme-Linked Immunosorbent Assay↗

PubMed1992

Enhanced sensitivity of a second generation ELISA for antibody to hepatitis C virus.

A second generation ELISA for combined detection of antibodies to three hepatitis C virus (HCV) recombinant proteins, i.e. C100, C33c and core, was compared with a first generation anti-HCV ELISA in which only antibodies to C100 are detected. The results of the ELISAs were evaluated in 225 haemophilia patients (panel A) and 44 patients with non-A, non-B (NANB) hepatitis (panel B). HCV infection was established by cDNA-polymerase chain reaction (PCR) (in panel B only) and by studying the anti-HCV reaction patterns in 4 separate ELISAs for detection of antibodies to the recombinant proteins C100, C33c, core and a combination of two synthetic peptides sp67/65 derived from the C100 region. The sensitivity for the detection of HCV infection had increased from 0.92[95% confidence interval (CI): 0.87-0.95] to 1.00 (95% CI: 0.89-1.00) in haemophiliacs and from 0.84 (95% CI: 0.66-0.95) to 1.00 (95% CI: 0.89-1.00) in NANB hepatitis patients when the second generation ELISA was used instead of the first generation ELISA. Concurrently the chance of a false negative result was reduced in panel A and B from 0.37 to 0 and from 0.28 to 0, respectively. Analysis of anti-HCV reaction patterns revealed that 172 of 206 (83.5%) anti-HCV ELISA-reactive haemophilia patients had antibodies to all 4 antigens tested. In the NANB hepatitis patients 18 of 31 (58.1%) anti-HCV ELISA-reactive subjects reacted with 4 antigens. In the PCR tested panel of NANB hepatitis patients 2 subjects who showed antibody reactivity to only one antigen and 5 patients with reactivity to 2 antigens were PCR-positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Viral↗

PubMed1992

Storage conditions of blood samples and primer selection affect the yield of cDNA polymerase chain reaction products of hepatitis C virus.

We have noticed that suboptimal specimen processing and storage conditions may cause false-negative results in the detection of hepatitis C virus (HCV) RNA in plasma or serum. To establish the influence of specimen handling in a serological laboratory on the rate of detection of HCV RNA by the cDNA polymerase chain reaction (cDNA-PCR), we tested routine serum samples and fresh-frozen plasma samples from the same bleeding from confirmed anti-HCV-positive blood donors. When primers from the NS3/NS4 region were used, HCV RNA was detected in fresh-frozen plasma from 67% of the donors, whereas positive results were obtained with only 50% of the serum samples that had been subjected to routine serological procedures. Analysis of the same samples with primers from the highly conserved 5'-terminal region (5'-TR) revealed an HCV RNA detection rate of 92% for both the routine and the fresh-frozen samples. However, the yield of the amplification product in routine samples was strongly reduced compared with that in fresh-frozen plasma. Comparison of both primer sets for cDNA-PCR showed that the 5'-TR primer set was 10- to 100-fold more effective in detecting HCV RNA. We also analyzed the effect of storage of whole EDTA-blood and serum at room temperature and at 4 degrees C on the yield of the amplification product. A rapid decline in detectable HCV RNA of 3 to 4 log units was observed within 14 days when whole blood and serum were stored at room temperature. By contrast, no perceptible reduction in the cDNA-PCR signal was found in freshly prepared serum stored at 4 degrees C.

Base Sequence↗

PubMed1992

Disappearance of hepatitis C virus RNA in plasma during interferon alpha-2B treatment in hemophilia patients.

To establish the effect of interferon alpha-2B (IFN-alpha) treatment on hepatitis C virus (HCV) viremia, rather than monitor the alanine aminotransferase (ALAT) values we measured HCV-RNA by cDNA-polymerase chain reaction (cDNA-PCR) in plasma before and during IFN-alpha treatment. Eight hemophilia patients with chronic hepatitis C were treated with IFN-alpha for 24 weeks: 5 MU daily for 2 weeks, 2.5 MU daily for 4 weeks, and 1.5 MU three times a week for 18 weeks. HCV-RNA, as measured by cDNA-PCR, was present in all patients before treatment. After 24 weeks of treatment HCV-RNA was no longer detectable in three of eight (37.5%) patients, whereas only one of eight (12.5%) patients showed complete ALAT normalization. In three of eight patients a transient response to IFN-alpha was seen, with renewed HCV-RNA detection after dose reduction. HCV-RNA measurement by cDNA-PCR appeared to be more sensitive in detecting relapse than ALAT measurement.

Alanine Transaminase↗

PubMed1992

New developments in hepatitis C.

Since the detection of hepatitis B virus (HBV) in the 1960s and hepatitis A virus in the 1970s, a considerable proportion of infections of (probably viral) hepatitis could not be classified. About 90% of transfusion-related hepatitis was identified as non-A/non-B. In 1988 investigators from the Chiron Company (USA) detected the non-A, non-B agent and named it hepatitis C virus (HCV). An anti-HCV antibody assay (ELISA) and subsequently confirmation tests (immunoblot and polymerase chain reaction) were developed. HCV infection results in a chronic carrier state of the virus in about 80%. Almost all HCV carriers have, irrespective of their liver function tests, histologic signs of chronic hepatitis and/or liver cirrhosis. Chronic HCV infection is, like HBV, also associated with the development of hepatocellular carcinoma. Most HCV carriers are infected by parenteral routes (intravenous drug use, blood transfusion, tattooing). Intravenous drug users and haemophilia patients have the highest risk (80-90%) of becoming infected. Sexual and perinatal transmission does not play an important role in spreading the infection. Antiviral therapy (alpha-interferon) in patients with chronic hepatitis C will normalize liver function tests in about 25% of the cases, but it is unclear if the HCV carrier state will disappear and if liver cirrhosis will be prevented. At present no specific immunoglobulin or vaccine preparations are available to prevent the HCV infection.

Carrier State↗

PubMed1991

[Congenital hypoplastic anemia in The Netherlands (1963-1989)].

Congenital hypoplastic anemia (CHA; syn: Diamond-Blackfan syndrome) is a rare disorder with one of two patients a year in the Netherlands. To get a better understanding of this disorder in the Netherlands we conducted a national retrospective study over a 25-year period (1963 till 1989). The medical reports of 19 patients who fulfilled the diagnostic criteria for CHA were studied. Almost all patients were diagnosed during the first three months of life. Dysmaturity was found in 50% of the patients and in 25% physical anomalies were observed. In 17 patients the bone marrow showed a hypoplastic erythropoiesis, but in 2 patients erythropoiesis was quantitatively normal. All patients were treated with prednisone and 74% of them responded initially. Five of these patients (26%) had a complete remission and 4 of them (21%) are in remission on low dose prednisone maintenance-treatment. Remarkably one patient went only into remission at the age of 17 years. Nine patients (47%) are transfusion-dependent and one patient has a stable hemoglobin level of about 5.0 mmol/l without treatment. This study further shows that the chance of achieving a remission was positively correlated with an early start of prednisone treatment and negatively with the manifestation of symptoms on the first day of life.

Clinical Laboratory Techniques↗