Biomedical subjects

Eva Herrmann

Publications and source records attributed to Eva Herrmann.

At least 19 recordsLinked to original sources

PubMed2006

CD8 T-cell recognition of multiple epitopes within specific Gag regions is associated with maintenance of a low steady-state viremia in human immunodeficiency virus type 1-seropositive patients.

The importance of HLA class I-restricted CD8 T-cell responses in the control of human immunodeficiency virus (HIV) infection is generally accepted. While several studies have shown an association of certain HLA class I alleles with slower disease progression, it is not fully established whether this effect is mediated by HIV-specific CD8 T-cell responses restricted by these alleles. In order to study the influence of the HLA class I alleles on the HIV-specific CD8 T-cell response and on viral control, we have assessed HIV-specific epitope recognition, plasma viral load, and expression of HLA class I alleles in a cohort of HIV-seropositive bar workers. Possession of the HLA class I alleles B5801, B8101, and B0702 was associated with a low median viral load and simultaneously with a broader median recognition of Gag epitopes compared to all other HLA alleles (twofold increase) (P = 0.0035). We further found an inverse linear relationship between the number of Gag epitopes recognized and the plasma viral load (R = -0.36; P = 0.0016). Particularly, recognition of multiple epitopes within two regions of Gag (amino acids [aa] 1 to 75 and aa 248 to 500) was associated with the maintenance of a low steady-state viremia, even years after acute infection.

CD8-Positive T-Lymphocytes↗

PubMed2006

The level of CD81 cell surface expression is a key determinant for productive entry of hepatitis C virus into host cells.

Recently a cell culture model supporting the complete life cycle of the hepatitis C virus (HCV) was developed. Searching for host cell determinants involved in the HCV replication cycle, we evaluated the efficiency of virus propagation in different Huh-7-derived cell clones. We found that Huh-7.5 cells and Huh7-Lunet cells, two former replicon cell clones that had been generated by removal of an HCV replicon by inhibitor treatment, supported comparable levels of RNA replication and particle production, whereas virus spread was severely impaired in the latter cells. Analysis of cell surface expression of CD81 and scavenger receptor class B type I (SR-BI), two molecules previously implicated in HCV entry, revealed similar expression levels for SR-BI, while CD81 surface expression was much higher on Huh-7.5 cells than on Huh7-Lunet cells. Ectopic expression of CD81 in Huh7-Lunet cells conferred permissiveness for HCV infection to a level comparable to that for Huh-7.5 cells. Modulation of CD81 cell surface density in Huh-7.5 cells by RNA interference indicated that a certain amount of this molecule (approximately 7 x 10(4) molecules per cell) is required for productive infection with a low dose of HCV. Consistent with this, we show that susceptibility to HCV infection depends on a critical quantity of CD81 molecules. While infection is restricted in cells expressing very small amounts of CD81, susceptibility rapidly rises within a narrow range of CD81 levels, reaching a plateau where higher expression does not further increase the efficiency of infection. Together these data indicate that a high density of cell surface-exposed CD81 is a key determinant for productive HCV entry into host cells.

Antigens, CD↗

PubMed2006

Dynamics of CD81 expression on lymphocyte subsets during interferon-alpha-based antiviral treatment of patients with chronic hepatitis C.

CD81 is a hepatitis C virus (HCV) coreceptor with important functions in lymphocytes. During treatment, CD81 expression may be changed directly by the antiviral therapy or indirectly by reduction of the HCV serum level. The regulation of CD81 on lymphocyte subtypes has not been investigated so far and may be relevant for the control of viral infection and treatment response. CD81 was analyzed by flow cytometry in CD8(+), CD4(+), CD19(+), and CD56(+) lymphocyte subtypes from 20 patients with chronic hepatitis C before, during, and after antiviral treatment with pegylated interferon-alpha (IFN-alpha) and ribavirin. A sustained virologic response (SVR) was achieved in 11 patients. Dynamics of CD81 were investigated in correlation with HCV-RNA dynamics and the outcome of therapy. During treatment, the following typical patterns of CD81 regulation were observed: down-regulation on CD8(+) T cells (P = 0.022) and most significantly, on CD56(+) natural killer cells (P < 0.001), transient up-regulation on CD19(+) B cells (P = 0.006), and weak and late down-regulation on CD4(+) T cells (P = 0.028). During treatment, CD81 expression was not associated with the HCV-RNA serum level on all lymphocyte subtypes. After end of treatment, CD81 increased again in CD8(+) and CD56(+) cells (P = 0.001, P = 0.002). On CD8(+) T cells post-treatment, CD81 remained lower in patients who achieved a SVR compared with patients who failed to eliminate HCV after treatment (P = 0.033). Lymphocyte subsets show different patterns of CD81 response before and during antiviral treatment, which are associated with administration of IFN-alpha and antiviral response.

Adult↗

PubMed2006

The kinetics of hepatitis C virus.

The kinetics of hepatitis C virus (HCV) RNA during the first weeks of interferon-based antiviral therapy can be analysed by specific mathematical models. Those models have been inspired by previous work on the kinetics of human immune deficiency virus (HIV) and hepatitis B virus (HBV) during antiviral therapy and are able to summarize important features of early response to antiviral therapy in patients chronically infected with HCV. Kinetic parameters of the underlying biological processes as viral clearance and infected cell loss as well as an efficiency factor of therapy on viral production can be obtained when fitting frequent quantifications of HCV RNA with such models. The main aims of analysing hepatitis C viral kinetics include the efficient comparison of different treatment regimens, prediction of virological response, and conclusions on antiviral mechanisms of therapy.

Antiviral Agents↗

PubMed2006

Viral kinetics in patients with chronic hepatitis C treated with the serine protease inhibitor BILN 2061.

We analysed viral kinetics from a 2-day treatment with BILN 2061, a serine protease inhibitor of hepatitis C virus, in patients chronically infected with genotype 1 hepatitis C virus. The efficiency (E), describing inhibition of viral production, was above 99.45% in all patients with minor or moderate fibrosis receiving doses of 200mg and 500 mg twice daily and larger than in previous studies for interferon-based treatments. However, epsilon was slightly smaller in patients with cirrhosis given 200mg and markedly smaller in patients given 25 mg. Estimates of viral clearance and infected-cell loss support conclusions on these rates and on treatment mechanisms from previous studies on interferon-alpha-based treatments.

Adult↗

PubMed2006

Amino acid variations in hepatitis C virus p7 and sensitivity to antiviral combination therapy with amantadine in chronic hepatitis C.

BACKGROUND: Formation of transmembrane ion channels by hepatitis C virus (HCV) p7 and abrogation of channel function by amantadine was demonstrated in vitro. The relevance of HCV p7 amino acid (aa) variations for response to antiviral therapy with amantadine is unknown. METHODS: HCV p7 was sequenced in 86 individuals who were infected with HCV genotype 1. Thirty-six of 86 patients received amantadine within an interferon-alpha (IFN-alpha)-based antiviral therapy. Helical wheel modelling for HCV p7 was performed. RESULTS: No significant correlation of overall aa variations within HCV p7 was observed with response to IFN-alpha-based therapy with amantadine in HCV genotype 1alpha/b infected patients. When analysis was restricted to non-conservative aa variations, a higher number of aa substitutions within complete HCV p7 and transmembrane helix 2 was associated with non-response in HCV-1b-infected patients receiving therapy with amantadine (P=0.015 and P=0.037, respectively), without amantadine (P=0.106 and P=0.118, respectively), and in the total cohort of HCV-1b-infected patients (P=0.00007 and P=0.011, respectively). Furthermore, substitution L20F was observed more often in non-responders than responders with HCV-1b infection and therapy with amantadine (P=0.099). By in silico modelling, aa 20 was located toward the p7 channel lumen. Substitution L20F may impair amantadine action by altering the shape of the ion channel pore. CONCLUSION: Substitution L20F within HCV p7 may be associated with non-response to combination therapy specifically with amantadine in HCV-1b-infected patients. Non-responders with HCV-1b infection showed higher numbers of non-conservative aa variations within HCV p7 than responders, irrespective of the application of amantadine.

Amantadine↗

PubMed2005

Treatment with daily consensus interferon (CIFN) plus ribavirin in non-responder patients with chronic hepatitis C: a randomized open-label pilot study.

BACKGROUND/AIMS: Therapeutic options for hepatitis C non-responder patients are limited. METHODS: We initiated an open-label pilot study to investigate the efficacy of CIFN plus ribavirin on viral kinetics, sustained virological response (SVR), and histological response in hepatitis C non-responder patients. Seventy-seven patients were enrolled to receive CIFN given daily in combination with 1000/1200 mg ribavirin. An 8-week induction-dosing regimen of 18 microg CIFN, followed by 9 microg for 40 weeks was compared to 9 microg CIFN for 48 weeks. 90% of patients were infected with HCV-genotype 1. RESULTS: Overall, 82% of the patients demonstrated an early virological response, 65% had an end-of-treatment response, and the SVR was 30%. Interferon/ribavirin non-responders demonstrated a SVR of 22%. Induction-dosing resulted in a greater first-phase HCV-RNA decay that, however, did not translate to better SVRs, presumably due to more dose modifications. High ALT, younger age, and second-phase viral kinetics were associated with SVR. Only sustained responders and relapse patients showed an improved liver histology. CONCLUSIONS: Daily dosing of CIFN plus ribavirin may be a promising concept for selected non-responder patients before considering therapies which are anti-viral but not curative. However, motivation and compliance are requisites and a CIFN induction is not required.

Adolescent↗

PubMed2005

Clinical significance of in vitro replication-enhancing mutations of the hepatitis C virus (HCV) replicon in patients with chronic HCV infection.

BACKGROUND: Mutations in nonstructural (NS) hepatitis C virus (HCV) proteins enhance replication in HCV-1a/b replicons. The prevalence of such mutations and their clinical significance in vivo are unknown. METHODS: Parts of HCV NS3 and NS4B-NS5B genes that included 31 in vitro replication-enhancing sites were sequenced for 26 patients with chronic HCV genotype 1 infection. RESULTS: Five patients showed specific mutations within NS3 at sites enhancing replication in the replicon. Those mutations were associated with a slower decrease in HCV RNA concentration during interferon (IFN)- alpha -based therapy (P = .007). Neither specific nor other mutations within NS3 and NS4B-NS5B were associated with baseline HCV RNA concentrations. Within NS5A, fewer mutations in the major HCV strain (P = .001) and increased quasi-species complexity (P = .02) and diversity (P = .02) correlated with increasing baseline HCV RNA concentrations. In silico analyses of NS3 protein structures suggested that the majority of observed mutations did not lead to major conformational changes. CONCLUSIONS: Specific mutations leading to enhanced replication in the replicon system were detected in 5 of 26 patients in vivo and were not associated with baseline HCV RNA concentrations but were associated with a slower decrease in HCV RNA concentration during IFN- alpha -based therapy. Quasi-species heterogeneity of NS5A correlated with baseline HCV RNA concentrations.

Adult↗

PubMed2005

Relationship between early HCV kinetics and T-cell reactivity in chronic hepatitis C genotype 1 during peginterferon and ribavirin therapy.

BACKGROUND/AIMS: To gain understanding of inter-individual differences of treatment response in hepatitis C virus genotype 1 (HCV-G1) patients, we investigated simultaneously the early HCV kinetics and virus-specific T-cell reactivity. METHODS: Thirty, treatment-naïve HCV-G1 patients received peginterferon-alfa2a 180 microg/week plus ribavirin 1000-1200 mg/day, with blood samples collected prospectively at protocol time-points. HCV RNA was quantitated with a TaqMan assay with mathematical modelling of HCV decay. Virus-specific CD4+/CD8+ T-cells were enumerated by Elispot assays. RESULTS: HCV kinetic analysis identified two subgroups: fast (18/30) and slow (12/30) treatment-responders. Although these subgroups did not differ in any baseline characteristics, fast responders (FR) showed greater antiviral efficacy (epsilon) than slow responders (SR) (84.5+/-3.2 vs. 65.2+/-7.0%, P=0.002), and a higher rate of infected cell loss (delta) (0.56+/-0.2 vs. 0.04+/-0.02, P=0.038). The viral load drop (baseline to treatment week 4) was higher in FR vs. SR group (3.5+/-1.1 vs. 1.4+/-0.6 log10IU/mL, P<0.001). T-cell reactivity to HCV increased only in FR (after the loss of viraemia), but not in SR patients. CONCLUSIONS: Assessment of early viral and T-cell kinetics during treatment reveals marked differences amongst HCV-G1 patients and may provide a basis for treatment individualization. Enhancement of antiviral T-cell reactivity requires rapid viraemia clearance, rather than immunostimulation alone.

Adult↗

PubMed2005

New kinetic models for the hepatitis C virus.

Viral kinetic modeling has played an important role in the analysis of HCV RNA decay after the initiation of antiviral therapy. Models have provided a means of evaluating the antiviral effectiveness of therapy, of estimating parameters such as the rate of virion clearance and the rate of clearance of hepatitis C virus (HCV)-infected cells, and they have suggested mechanisms of action for both interferon and ribavirin. Nevertheless, the models that were originally formulated were unable to explain all of the observed HCV RNA profiles. We provide an update on the state of HCV kinetic modeling and discuss new models that have taken into consideration the different pharmacokinetics of standard and pegylated forms of interferon, allow for changes in drug effectiveness as drug concentrations fall between dosing intervals, and that have incorporated alanine aminotransferase kinetics and aspects of immune responses to provide a more comprehensive picture of the biology underlying changes in HCV RNA during therapy.

Antiviral Agents↗

PubMed2005

Peginterferon-alpha-2a (40KD) and ribavirin for 16 or 24 weeks in patients with genotype 2 or 3 chronic hepatitis C.

BACKGROUND & AIMS: Standard therapy of patients with chronic hepatitis C virus (HCV) infected with HCV genotype-2 or -3 is the combination of pegylated interferon-alpha and ribavirin for 24 weeks. Whether shorter treatment durations are possible for these patients without compromising sustained virologic response rates is unknown. METHODS: Patients chronically infected with HCV-2 (n = 39), HCV-2/3 (n = 1), or HCV-3 (n = 113) were treated with peginterferon-alpha-2a (180 microg/wk) plus ribavirin 800-1200 mg/day. HCV RNA was quantitatively assessed after 4 weeks. Patients with a rapid virologic response (HCV RNA below 600 IU/mL) were randomized for a total treatment duration of 16 (group A) or 24 weeks (group B). All patients with HCV RNA > or =600 IU/mL at week 4 (group C) were treated for 24 weeks. End-of-treatment and sustained virologic response were assessed by qualitative RT-PCR (sensitivity 50 IU/mL). RESULTS: Only 11 of 153 patients (7%) were allocated to group C. End-of-treatment and sustained virologic response rates were 94% and 82%, (group A), 85% and 80% (group B), and 73% and 36% (group C), respectively. In patients infected with genotype HCV-3 and high viral load (>800,000 IU/mL), a significant lower sustained virologic response rate was found than in patients infected with HCV-3 and a viral load lower or equal to 800,000 IU/mL (59% vs 85%, respectively; P = .003). CONCLUSIONS: In HCV-2 and -3 (low viral load)-infected patients who have a rapid virologic response, treatment for 16 weeks with peginterferon-alpha-2a and ribavirin is sufficient. In patients infected by HCV-3 (high viral load), longer treatment may be necessary.

Adult↗

PubMed2005

Comparison of transcription mediated amplification (TMA) and reverse transcription polymerase chain reaction (RT-PCR) for detection of hepatitis C virus RNA in liver tissue.

BACKGROUND: Transcription mediated amplification (TMA) is known to be one of the most sensitive detection assays for hepatitis C virus (HCV) RNA in serum but has not yet been evaluated in liver tissue. It is unknown whether the higher sensitivity of TMA in comparison with polymerase chain reaction (PCR)-based assays is related to a higher efficiency of the extraction and/or amplification step. OBJECTIVES: The sensitivity of a TMA-based assay (Versant HCV RNA Qualitative assay, Bayer Diagnostics) and a standard RT-PCR-based assay (Cobas Amplicor HCV 2.0, Roche Diagnostics) was compared in formalin-fixed paraffin-embedded liver biopsy specimens of patients with chronic hepatitis C. STUDY DESIGN: After deparaffinization of 7.5 microm liver sections HCV RNA was extracted by standard phenol/chloroform. HCV RNA dilution panels were transferred in parallel to cDNA synthesis and amplification steps of PCR and TMA. Furthermore, TMA amplification from stepwise diluted HCV sera was performed following RNA extraction by either microcentrifuge colums (QIAmp Viral RNA spin Kit, Qiagen, Hilden, Germany) or magnetic microparticles (VERSANT HCV RNA Qualitative assay). RESULTS: The total number of HCV RNA positive liver specimens detected by TMA was higher compared with those detected by RT-PCR (P=0.032). The total number of TMA positive serum samples was higher when HCV RNA was extracted using magnetic microparticles in comparison with multicentrifuge column extraction (P=0.019). CONCLUSION: Our results suggest that both the extraction and amplification step of the TMA-based assay contribute to the higher sensitivity compared with standard RT-PCR.

Formaldehyde↗

PubMed2005

Viral kinetics in patients with lamivudine-resistant hepatitis B during adefovir-lamivudine combination therapy.

BACKGROUND/AIMS: Mathematical analysis of viral kinetics during lamivudine-adefovir combination therapy has not yet been performed in patients with lamivudine-resistant hepatitis B. METHODS: In 8 patients with lamivudine-resistant hepatitis B, adefovir dipivoxil (10 mg/day) was added to ongoing lamivudine. Viral decay during the first 8 weeks of combination therapy was described by a biphasic model to determine the efficacy: epsilon, of blocking viral production, the clearance: c, of free virus, and the loss of infected cells: delta. RESULTS: Median epsilon was 98%, median c was 0.7/day, and median delta was 0.07/day. No significant association was found between viral kinetic and baseline parameters and virologic and biochemical treatment response. When compared with viral kinetic constants reported for higher dose adefovir dipivoxil monotherapy, epsilon was lower (P=0.026) and delta was higher (P=0.008) in this study whereas c did not differ between both studies. CONCLUSIONS: Although a recent study did not show any differences in the reduction of HBV DNA comparing monotherapy with adefovir dipivoxil to adefovir-lamivudine combination therapy in patients with lamivudine-resistant chronic hepatitis B, mathematical analysis of early viral kinetics suggests an additional effect of lamivudine on the infected cell loss during adefovir-lamivudine combination therapy.

Adenine↗

PubMed2005

["Truth at the bedside"--continuing medical education and breaking bad news].

INTRODUCTION: Discussions with seriously-ill patients are part of the physicians' tasks. These discussions demand good communication skills. In this paper we present the concept of a postgraduate course for physicians on ethics and breaking bad news, as well as the results of the course evaluation. METHODS: Questionnaire distributed before and immediately after the course using closed-ended questions and Likert scales. RESULTS: 37 physicians (response rate: 84.1%) from seven specialties completed the questionnaires. Twenty-eight respondents (75.6%) had been involved in breaking bad news more than 5 times per month. Approximately half of the respondents (N = 18; 48.6%) rated the discussions on the limits of curative treatment as particularly difficult communication situations. With one exception, all physicians denied the existence of guidelines on breaking bad news in their institutions. Compared with the beginning of the course, the respondents rated their communication skills to be improved at the end of the course. Positive evaluations were obtained for practice relevance, teaching methods, and organisation of the course. CONCLUSION: The interest in this optional postgraduate course and the feedback of the participants indicate the necessity of professional training on difficult communication situations. The self-rating of improved communication skills may be interpreted as a positive effect of the course. Observational studies are required to confirm the effects of the training.

Education, Medical, Continuing↗

PubMed2004

Association of HCV-related mixed cryoglobulinemia with specific mutational pattern of the HCV E2 protein and CD81 expression on peripheral B lymphocytes.

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Antigens, CD↗

PubMed2004

Viral kinetics during antiviral therapy in patients with chronic hepatitis C and persistently normal ALT levels.

The aim of the present study was to compare viral kinetics between patients with chronic hepatitis C and persistently normal alanine aminotransferase (ALT) levels and those with elevated ALT levels. Kinetic parameters were derived from nonlinear, least square fitting of serum hepatitis C virus RNA quantifications collected from patients with chronic hepatitis C and persistently normal (n = 20) and elevated (n = 19) ALT levels before and during treatment with 180 mug pegylated interferon alpha-2a once weekly plus daily ribavirin. Patients with chronic hepatitis C and persistently normal ALT levels showed a trend to lower pretreatment infected cell loss (delta) (P = .13) but no differences in efficacy of blocking virus production (epsilon) and infected cell loss during treatment (mdelta) compared with patients with elevated ALT levels. Differences were significant for epsilon (P = .02) and delta (P = .04) when applying updated "healthy" levels for ALT (0.75 times and 0.63 times upper limit of normal for male and female patients, respectively). A significant reduction of the kinetic parameters epsilon, delta, and mdelta was observed in patients with elevated gamma-glutamyltranspeptidase (GGT) levels compared with patients with normal GGT levels (P = .02, P = .005, and P = .02, respectively). In conclusion, viral kinetics are similar in patients with chronic hepatitis C and persistently normal ALT levels and those with elevated ALT levels. However, in patients with elevated GGT levels, a major association with reduced efficacy of blocking virus production and lower infected cell loss was observed. These data show that virological response in patients with chronic hepatitis C is less associated with baseline ALT than with GGT levels.

Adult↗

PubMed2004

Association of serum interleukin-8 with virologic response to antiviral therapy in patients with chronic hepatitis C.

BACKGROUND/AIMS: Upregulation of interleukin-8 by the hepatitis C virus non-structural-5A-protein leads to inhibition of the antiviral activity of interferon-alpha in vitro. The clinical significance of interleukin-8 levels for virologic response to interferon-alpha-based treatment in patients with chronic hepatitis C is unknown. METHODS: We investigated serum interleukin-8 in 59 healthy controls and 214 patients with chronic hepatitis C (genotype 1, n=152; genotype 2, 3, n=62) and different outcome to interferon-alpha-based therapy. RESULTS: In patients with chronic hepatitis C higher interleukin-8 levels were observed compared with healthy controls (P<0.0001). Hepatitis C genotype 1-infected patients with early and overall virologic response to interferon-alpha-based therapy showed lower interleukin-8 levels than non-responders (P=0.025 and P=0.035, respectively). In all patients, elevated interleukin-8 levels were associated with cirrhosis (genotype 1, P=0.0003; genotype 2, 3, P=0.009). Interleukin-8 levels in sustained virologic responders were still higher 24 weeks after the end-of-therapy compared with healthy controls (P<0.0001). CONCLUSIONS: In genotype 1 infected patients, low pretreatment serum interleukin-8 is associated with virologic response to interferon-alpha-based therapy. Thus, the conclusion from in vitro studies that the upregulation of interleukin-8 by the hepatitis C virus contributes to the inhibition of the antiviral actions of interferon-alpha may also be applicable in vivo.

Adult↗

PubMed2004

Sleep deprivation in honey bees.

Rest at night in forager honey bees (Apis mellifera) meets essential criteria of sleep. This paper reports the effect of a 12-h total sleep deprivation (SD) by forced activity on the behaviour of these animals. The behaviour of sleep-deprived animals is compared with that of control animals under LD [periodic alternation between light (L) and darkness (D)] 12 : 12 hours. SD for 12 h during the first D period resulted in a significant difference with respect to the parameter 'hourly amount of antennal immobility' between sleep-deprived and control animals during the remaining L and D periods. This difference did not occur in the L period following the deprivation night, but rather it became obvious at the beginning of the following D period. The increase of the amount of antennal immobility in sleep-deprived bees was accompanied by an increase of the duration of episodes of antennal immobility. Moreover, the latency from 'lights off' to the first episode of antennal immobility lasting 20 s or longer ('deep sleep latency') tended to be shorter in sleep-deprived than in control animals. Disturbing the bees during the day (L period) did not result in such differences between disturbed and control animals. Highest reaction thresholds in sleeping honey bees occur during long episodes of antennal immobility. We therefore conclude that honey bees compensate a sleep deficit by intensification (deepening) of the sleep process and thus that sleep in honey bees, like that in other arthropods and mammals, is controlled by regulatory mechanisms.

Animals↗