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Biomedical subjects

G Gerken

Publications and source records attributed to G Gerken.

At least 181 records · Page 10Linked to original sources
PubMed1994

Quantitation of HCV-replication using one-step competitive reverse transcription-polymerase chain reaction and a solid phase, colorimetric detection method.

A solid phase assay for the colorimetric detection of competitively amplified HCV-cDNA has been established and used to investigate clinical samples from patients with chronic hepatitis. The assay is based on the reduction in the amplification of an hepatitis C virus-related competitor molecule by wild-type hepatitis C virus during polymerase chain reaction. The internal standard contains a lac operator sequence, allowing the amount of amplified competitor to be determined using a lac I-repressor/beta-galactosidase fusion protein. The reduction in the amplification of competitor is dependent upon the concentration of HCV-RNA in the original sample. External hepatitis C virus wild-type standards are used to calibrate each concurrently tested set of patients. We present and discuss the potential benefit, but also the limitations of this new approach for quantifying hepatitis C virus viremia. In 47 serum samples from 28 patients with chronic hepatitis C virus infection, including five repeatedly tested alpha HCV positive patients under interferon therapy, viral titer was determined. Sera from nine healthy blood donors served as controls. The sensitivity and specificity of this procedure are identical to those of conventional nested polymerase chain reaction. As both internal and external standards are used in every assay and final detection of amplicons can be carried out in microtiter plates, this reliable and time-saving test system may be routinely applied for monitoring antiviral treatment or for studying the relation of plus- and minus-stranded HCV-RNA in infected tissues.

Colorimetry↗
PubMed1994

Detection of hepatitis C virus replication in ovarian metastases of a patient with hepatocellular carcinoma.

Hepatocellular carcinoma is one of the most common human cancers with an annual incidence of about 1,000,000 cases worldwide. Although hepatocellular carcinoma is predominant in hepatitis B virus endemic areas, it has also become a major problem in Europe, Japan and North America in close association with the increasing incidence of hepatitis C virus infection. The pathogenetic role of hepatitis C virus infection in the development of HBsAg-negative hepatocellular carcinoma needs to be clarified. In this paper the case of a 66-year-old HBsAg-negative and anti-HCV positive female who developed hepatocellular carcinoma in a cirrhotic liver is reported. After 1 year of follow up, urgent laparotomy had to be performed due to highly differentiated ovarian metastases of the hepatocellular carcinoma. Plus- and minus-stranded HCV-RNA was detected by reverse transcription and "nested" polymerase chain reaction in both the patient's serum and in the metastatic ovarian tissue.

Aged↗
PubMed1994

The asialoglycoprotein receptor mediates hepatic binding and uptake of natural hepatitis B virus particles derived from viraemic carriers.

As a putative mechanism of hepatitis B virus (HBV) uptake into hepatocytes the interaction between HBV and the hepatic, human-derived asialoglycoprotein receptor (ASGPR) was investigated. Sera from patients with different variations of hepatitis B surface antigen-(HBsAg) positive chronic hepatitis, HBV particles isolated from HBV carriers with high-titre viraemia and commercial HBsAg served as sources of HBV. ASGPR was affinity-purified from human liver. HBV that had bound to isolated ASGPR was either detected by radioimmunoassay using solid-phase bound ASGPR or enzyme immunoassay with biotin-ASGPR bound to immobilized HBV. Furthermore, binding and uptake of purified, 125I-labelled HBV particles into human hepatoma cell lines (HepG2 and HuH7), which constitutively express functional ASGPR molecules, were compared to that of ASGPR-negative COS cells. As a result HBV was found to bind to purified human ASGPR in two different assays. Circulating virus particles from sera with high titre viraemia showed the highest attachment activity to ASGPR. HBV binding to purified ASGPR was saturable and inhibitable by an excess of D-galactose-bearing ligands, by EDTA and anti-receptor immunoglobulin. Lysis of particles by adding detergent abolished immunodetectable HBV binding to purified ASGPR. Commercial HBsAg did not adhere to solid phase-immobilized ASGPR. Monoclonal anti-preS1 antibody (MA18/7) but not anti-preS2 antibody (Q19/10) inhibited virus attachment. Purified and radiolabelled HBV particles showed binding to HepG2 and HuH7 cells but to much lesser degree to COS cells. Cellular binding of HBV was significantly inhibited by blocking of ASGPR function. Both ASGPR ligands and rabbit anti-ASGPR immunoglobulin but not non-immune rabbit serum inhibited uptake of radiolabelled HBV particles into HepG2 cells or HuH7 cells, respectively. This study suggests that HBV virions may enter human hepatocytes via ASGPR molecules by attachment of viral preS1-related envelope binding sites to this receptor.

Acute Disease↗
PubMed1994

Phenotypical analysis and cytokine release of liver-infiltrating and peripheral blood T lymphocytes from patients with chronic hepatitis of different etiology.

Cytokines released by infiltrating T cells may contribute to the hepatic injury in chronic hepatitis. Therefore, we characterized peripheral blood- and liver-infiltrating T cells from patients with chronic hepatitis of different etiology and determined the T cell phenotypes and the cytokine release. Liver tissue and peripheral blood-derived T cells from patients with autoimmune hepatitis and primary biliary cirrhosis predominantly expressed CD4-molecules and the alpha- and beta-chains of the T cell receptor (TCR). In chronic viral hepatitis B and C, liver- and blood-derived T cells were preferentially CD8+ T cells expressing the alpha beta TCR. Mitogenic stimulation with irradiated Daudi lymphoma cells and phytohemagglutinin led to a strong release of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) by T cells in patients with chronic hepatitis and in healthy controls. T cells from patients with primary biliary cirrhosis and some patients with autoimmune hepatitis showed a significantly higher secretion of interleukin-4 (IL-4) and interleukin-10 (IL-10) than T cells from patients with chronic viral hepatitis or healthy controls. Histologic inflammatory activity did not correlate with the amount of cytokines released after mitogenic activation. In conclusion, liver tissue and peripheral blood T cells of patients with autoimmune hepatitis and primary biliary cirrhosis were dominated by CD4+ TCR alpha beta+ T helper/inducer cells, whereas in chronic viral hepatitis an enrichment of CD8+ TCR alpha beta + cytotoxic/suppressor T cells was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Helicobacter sp. strain Mainz isolated from an AIDS patient with septic arthritis: case report and nonradioactive analysis of 16S rRNA sequence.

A campylobacter-like organism was isolated from an effusion of the left knee joint of an AIDS patient 2 weeks after bacteremia with a morphologically identical organism. Amplified genomic 16S rRNA sequences were analyzed by a nonradioactive blotting technique. The closest match was found with Helicobacter fenelliae (97.7% homology). Sequence data and phenotype suggest that the isolate may represent a so far unrecognized species of the genus Helicobacter.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Epidemiology of hepatocellular carcinoma. Evaluation of viral and other risk factors in a low-endemic area for hepatitis B and C.

To assess whether hepatocellular carcinoma (HCC) in patients with cirrhosis of the liver is associated with particular risk factors, a retrospective, case-control study was performed. Eighty-six patients with HCC (90% had underlying cirrhosis of the liver) were compared with 86 controls who had cirrhosis but not hepatocellular carcinoma. Hepatitis B surface antigen (HBsAg), antibodies to hepatitis B core antigen (anti-HBc), and to hepatitis C virus (anti-HCV) were evaluated; and alcohol and nicotine abuse were assessed by history. The prevalence of HBsAg and anti-HBc was similar in both, case and control patients. Antibodies to hepatitis C virus were detected more frequently among patients with HCC and cirrhosis (37%) compared to cirrhosis alone (22%). Alcohol abuse was found more frequently in patients with cirrhosis alone. Smoking habits were comparable between the two groups. None of the tested variables were related to an increased risk for HCC. Using an ordinary logistic regression approach, none of the variables could be identified as an independent risk factor for HCC. However, the combination of hepatitis B virus infection and hepatitis C virus infection was more prevalent in the patients with hepatocellular carcinoma and cirrhosis (48%) when compared to patients with cirrhosis alone (13%) (odds ratio 6.364; CI 1.149-35.229). In conclusion, we failed to identify independent risk factors for the development of HCC in Germany. However, the combination of hepatitis B and C virus infection increases the risk for liver cancer. Molecular analyses have to be performed to elucidate viral hepatocarcinogenesis.

Aged↗
PubMed1993

Reliability of polymerase chain reaction for detection of hepatitis C virus.

The polymerase chain reaction (PCR) is used to detect hepatitis C virus (HCV) RNA, and the results of this assay may have a bearing on management of patients. We tested 31 laboratories for performance of HCV PCR with a coded panel that comprised 4 HCV-positive plasma samples, 6 HCV-negative samples, and two dilution series of HCV-positive plasma. 15 (48%) laboratories had faultless results with both dilution series, and 16 (52%) laboratories reported erroneous results with one or both series. 10 (32%) laboratories had faultless results when testing undiluted plasma samples, 11 (35%) produced a false-negative result with a weak-positive sample, and 10 (32%) produced false negative and/or false positive results. Only 5 (16%) laboratories performed faultlessly with the entire panel of samples. Reports of presence of HCV should be interpreted with care until reliable HCV-RNA detection becomes widely available.

Clinical Laboratory Techniques↗
PubMed1993

Significance and relevance of serum preS1 antigen detection in wild-type and variant hepatitis B virus (HBV) infections.

These studies assessed whether the serum expression of preS1 antigen could be a useful HBV marker for monitoring the progress of antiviral therapy in the treatment of chronic active hepatitis B (CAH-B) virus infections. Our findings indicate that: 1) the rearrangements we observed in the preS region of mutated HBV DNA molecules during chronic infection did not effect the preS1 sequence (21-47) critical for HBV infectivity; 2) the persistence or even the rebound of preS1 antigen expression during follow-up in responders to antiviral therapy may indicate virus persistence, suggesting the possibility of relapse through wild-type HBV or the emergence of HBV variants following the immunoelimination phase.

Carrier State↗
PubMed1993

Hepatitis C virus associated primary hepatocellular carcinoma in a noncirrhotic liver.

The case of a 71-year-old man with a primary hepatocellular carcinoma in a non-cirrhotic liver is reported. There were no risk factors of hepatocellular carcinoma (HCC)-like liver cirrhosis, alcohol drinking, tobacco smoking, exposure to vinyl chloride, thorotrast, aflatoxin or alpha 1-antitrypsin deficiency. Serologically, the patient was positive for antibodies to the hepatitis B virus (anti-HBc, anti-HBs) and for anti-hepatitis C virus (HCV) antibodies. Virologically, positive and negative strands of HCV RNA could be detected in the patient's serum and tumorous liver tissue by reverse transcription polymerase chain reaction as a sign of persistent HCV replication. Histologically, the HCC was completely surrounded by liver tissue which showed the signs of nodular regenerative hyperplasia. Indeed, the mechanism of hepatocarcinogenesis remains to be clarified. However, this case supports the observation that HCC may also develop in patients with HCV infection without preexisting liver cirrhosis.

Aged↗
PubMed1993

IL-2, IL-3, and IFN-gamma differently affect in vivo frequencies of circulating precursors of cytotoxic T lymphocytes (CTL-P).

Experimental animal and human in vivo studies have previously demonstrated the impact of exogenous administration of various cytokines on frequencies of circulating myeloid and LAK precursor cells. For the first time we investigated whether exogenous cytokines, in the absence of antigenic challenge, may also influence frequencies of circulating antigen-specific cytotoxic T-lymphocyte precursor cells. We further asked whether triggering of autoimmune pathways as has been reported for several cytokines can be confirmed on the cellular level by demonstration of induction of autoreactive CTL-p. Limiting dilution analysis was used to determine alloreactive CTL-p frequencies in 31 patients with nonhematologic diseases before and after short-term systemic treatment with either rIL-2 (4.8 x 10(6) IU/m2 bid), rIL-3 (2.5, 5.0 or 10.0 micrograms/kg qd), rGM-CSF (5 micrograms/kg qd), rIFN-gamma (200 or 400 micrograms qd), or IFN-alpha (3 or 5 x 10(6) IU qod). Simultaneously, autoreactive CTL-p frequencies were determined by split-well analysis in 25 of these patients. We found that rIL-2 significantly expands the circulating precursor pool of alloreactive CTL (p < 0.05). rIL-3 affected CTL-p frequencies in a dose-dependent fashion. Low and intermediate doses of rIL-3 did not exhibit significant effects, whereas 10 micrograms/kg rIL-3 led to expansion of alloreactive CTL-p in the same order of magnitude as did rIL-2. This effect was statistically significant when compared with rGM-CSF (p < 0.02), which apparently had no influence on alloreactive CTL-p frequencies. In contrast to rIL-2 and rIL-3, exogenous rIFN-gamma markedly reduced the circulating precursor pool of CTL. This again was statistically significant compared with rIFN-alpha (p < 0.03), which, like rGM-CSF, did not exhibit any effects on the level of alloreactive CTL-p. Frequencies of autoreactive CTL-p were invariably below the limit of detection in our system (< 1/300,000). In conclusion, these data demonstrate that (a) short-term systemic administration of rIL-2, rIL-3, and rIFN-gamma differently affects the clone size of circulating precursors of alloreactive CTL in man, while rGM-CSF and rIFN-alpha do not exhibit measurable effects, and (b) none of the cytokines administered is capable of uncovering detectable frequencies of autoreactive CTL-p.

Autoimmunity↗
PubMed1993

Autoantibodies against the human asialoglycoprotein receptor: effects of therapy in autoimmune and virus-induced chronic active hepatitis.

The hepatic asialoglycoprotein receptor (ASGPR) was recently identified as a target antigen for both humoral and cellular immune response in inflammatory liver diseases. Thereby anti-ASGPR autoantibodies directed against human substrate were closely associated with autoimmune chronic active hepatitis. The present study compares the occurrence, titer and immunoglobulin classification of anti-human(h-)-ASGPR antibodies in 23 patients with newly diagnosed autoimmune chronic hepatitis before and after initiation of immunosuppressive therapy to 22 patients with autoimmune hepatitis in remission. Additionally, 1-year follow-up examinations of 42 patients with HBsAg-positive chronic hepatitis and of 32 patients with chronic hepatitis C receiving recombinant interferon-alpha were included. Nineteen of 23 patients with newly diagnosed and 9/22 with autoimmune hepatitis in remission, 5/42 with untreated chronic hepatitis B and 5/32 patients with chronic hepatitis C exhibited anti-h-ASGPR at the beginning of the study. In autoimmune hepatitis anti-h-ASGPR were found in higher titers (median > 1:1000) than in viral hepatitis (maximum 1:400). After initiation of immunosuppressive therapy in autoimmune hepatitis anti-h-ASGPR decreased sharply. Eight of 19 patients eliminated anti-h-ASGPR within 18 months in contrast to 11 patients with persistent anti-h-ASGPR titer over 18 months and longer. Anti-h-ASGPR with maximum titer of 1:600 were detected in 5 patients with chronic hepatitis B (transiently in 4/5 patients) and in 2 patients with chronic hepatitis C during interferon-alpha. Anti-h-ASGPR were from immunoglobulin classes IgG and IgM in cases with untreated autoimmune hepatitis and chronic hepatitis B and C exhibiting mainly IgG2-subclass in autoimmune and IgG4 in viral hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Autoreactive liver-infiltrating T cells in primary biliary cirrhosis recognize inner mitochondrial epitopes and the pyruvate dehydrogenase complex.

Primary biliary cirrhosis (PBC) is characterized by lymphoid infiltrates in the portal tracts of the liver and the occurrence of antimitochondrial autoantibodies in serum directed against components of the pyruvate dehydrogenase complex and the other alpha-keto acid dehydrogenase complexes. These enzymes are located on the inner mitochondrial membrane. The destruction of the biliary tract in PBC is thought to be mediated by autoreactive liver-infiltrating T cells exerting cytotoxic activity or releasing certain lymphokines. In this study the reactivity of liver infiltrating T cells was shown to a bovine pyruvate dehydrogenase complex (PDH), a purified E2 subunit (PDH-E2) and a crude preparation of human liver mitoplasts (HLM), i.e. mitochondria depleted of their outer membranes. Peripheral blood lymphocytes (PBL) from 11 of 15 patients (73.3%) with PBC showed a HLA class II-restricted proliferative response to the PDH complex whereas PBL from patients with chronic viral hepatitis, autoimmune hepatitis or extrahepatic cholestatic icterus (n = 20) and healthy controls (n = 5) did not. In addition 13 of 15 PBL from patients with PBC (86.6%) and three of nine PBL from patients with autoimmune hepatitis (33.3%) reacted with the crude HLM preparation whereas no reactivity was found with PBL from eight patients with chronic viral hepatitis, three patients with extrahepatic cholestasis or five healthy controls. Clonal analysis of 115 liver-infiltrating T cells derived from two diagnostic liver biopsies of patients with PBC revealed a predominance of activated CD4+CD8- T helper cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗