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Dive into the research topics where Gaby Knecht is active.

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Featured researches published by Gaby Knecht.


BMC Gastroenterology | 2012

Assessment of liver fibrosis and associated risk factors in HIV-infected individuals using transient elastography and serum biomarkers

Johannes Vermehren; Annika Vermehren; Axel Mueller; Amina Carlebach; Thomas A. Lutz; Peter Gute; Gaby Knecht; Christoph Sarrazin; Mireen Friedrich-Rust; Nicole Forestier; Thierry Poynard; Stefan Zeuzem; Eva Herrmann; Wolf Peter Hofmann

BackgroundLiver fibrosis in human immunodeficiency virus (HIV)-infected individuals is mostly attributable to co-infection with hepatitis B or C. The impact of other risk factors, including prolonged exposure to combined antiretroviral therapy (cART) is poorly understood. Our aim was to determine the prevalence of liver fibrosis and associated risk factors in HIV-infected individuals based on non-invasive fibrosis assessment using transient elastography (TE) and serum biomarkers (Fibrotest [FT]).MethodsIn 202 consecutive HIV-infected individuals (159 men; mean age 47 ± 9 years; 35 with hepatitis-C-virus [HCV] co-infection), TE and FT were performed. Repeat TE examinations were conducted 1 and 2 years after study inclusion.ResultsSignificant liver fibrosis was present in 16% and 29% of patients, respectively, when assessed by TE (≥ 7.1 kPa) and FT (> 0.48). A combination of TE and FT predicted significant fibrosis in 8% of all patients (31% in HIV/HCV co-infected and 3% in HIV mono-infected individuals). Chronic ALT, AST and γ-GT elevation was present in 29%, 20% and 51% of all cART-exposed patients and in 19%, 8% and 45.5% of HIV mono-infected individuals. Overall, factors independently associated with significant fibrosis as assessed by TE (OR, 95% CI) were co-infection with HCV (7.29, 1.95-27.34), chronic AST (6.58, 1.30-33.25) and γ-GT (5.17, 1.56-17.08) elevation and time on dideoxynucleoside therapy (1.01, 1.00-1.02). In 68 HIV mono-infected individuals who had repeat TE examinations, TE values did not differ significantly during a median follow-up time of 24 months (median intra-patient changes at last TE examination relative to baseline: -0.2 kPa, p = 0.20).ConclusionsChronic elevation of liver enzymes was observed in up to 45.5% of HIV mono-infected patients on cART. However, only a small subset had significant fibrosis as predicted by TE and FT. There was no evidence for fibrosis progression during follow-up TE examinations.


Antimicrobial Agents and Chemotherapy | 2011

Comparison of Drug Resistance Scores for Tipranavir in Protease Inhibitor-Naïve Patients Infected with HIV-1 B and Non-B Subtypes

Martin Stürmer; Christoph Stephan; Peter Gute; Gaby Knecht; Markus Bickel; Hans-Reinhard Brodt; Hans Wilhelm Doerr; Lutz Gürtler; Pierre Lecocq; Margriet Van Houtte

ABSTRACT Genotypes of samples from protease inhibitor-naïve patients in Frankfurts HIV Cohort were analyzed with five tipranavir resistance prediction algorithms. Mean scores were higher in non-B than in B subtypes. The proportion of non-B subtypes increased with increasing scores, except in weighted algorithms. Virtual and in vitro phenotype analyses of samples with increased scores showed no reduced tipranavir susceptibility. Current algorithms appear suboptimal for interpretation of resistance to tipranavir in non-B subtypes; increased scores might reflect algorithm bias rather than “natural resistance.”


International Journal of Molecular Sciences | 2016

Persistence of HCV in Acutely-Infected Patients Depletes C24-Ceramide and Upregulates Sphingosine and Sphinganine Serum Levels

Georgios Grammatikos; J. Dietz; Nerea Ferreirós; Alexander Koch; G. Dultz; Dimitra Bon; Ioannis Karakasiliotis; Thomas Lutz; Gaby Knecht; Peter Gute; Eva Herrmann; Stefan Zeuzem; Penelope Mavromara; Christoph Sarrazin; Josef Pfeilschifter

Hepatitis C virus (HCV) substantially affects lipid metabolism, and remodeling of sphingolipids appears to be essential for HCV persistence in vitro. The aim of the current study is the evaluation of serum sphingolipid variations during acute HCV infection. We enrolled prospectively 60 consecutive patients with acute HCV infection, most of them already infected with human immunodeficiency virus (HIV), and serum was collected at the time of diagnosis and longitudinally over a six-month period until initiation of antiviral therapy or confirmed spontaneous clearance. Quantification of serum sphingolipids was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Spontaneous clearance was observed in 11 out of 60 patients (18.3%), a sustained viral response (SVR) in 43 out of 45 patients (95.5%) receiving an antiviral treatment after follow-up, whereas persistence of HCV occurred in six out of 60 patients (10%). C24-ceramide (C24-Cer)-levels increased at follow-up in patients with spontaneous HCV eradication (p < 0.01), as compared to baseline. Sphingosine and sphinganine values were significantly upregulated in patients unable to clear HCV over time compared to patients with spontaneous clearance of HCV infection on follow-up (p = 0.013 and 0.006, respectively). In summary, the persistence of HCV after acute infection induces a downregulation of C24Cer and a simultaneous elevation of serum sphingosine and sphinganine concentrations.


Virology | 2015

Evolution and function of the HCV NS3 protease in patients with acute hepatitis C and HIV coinfection

J. Dietz; Thomas A. Lutz; Gaby Knecht; Peter Gute; Caterina Berkowski; Christian Lange; Pavel Khaykin; Christoph Stephan; Hans-Reinhard Brodt; Eva Herrmann; Stefan Zeuzem; Christoph Sarrazin

Little is known about the importance of the hepatitis C virus (HCV) NS3 protease in acute hepatitis C. In this prospective study, 82 consecutive patients with acute hepatitis C and human immunodeficiency virus (HIV) coinfection were enrolled. Individuals were infected with highly related HCV strains and the baseline NS3 quasispecies diversity and complexity was higher compared to a chronic hepatitis C control group (P<0.0001). Both parameters were comparable in patients with spontaneous clearance (n=6) versus treatment-induced SVR (n=5) or development of chronic hepatitis C (n=9). Longitudinal NS3 quasispecies kinetics showed a trend to a decreasing diversity and complexity (P<0.05) within 4 weeks in patients with spontaneous clearance compared to the other groups. The innate immune signalling protein CARDIF was cleaved to a similar extent independent of the outcome. Together with a more pronounced viral load decline (P<0.05), an early decreasing NS3 quasispecies evolution indicates spontaneous clearance of acute hepatitis C.


Journal of Antimicrobial Chemotherapy | 2009

Once-daily treatment with saquinavir mesylate (2000 mg) and ritonavir (100 mg) together with a fixed-dose combination of abacavir/lamivudine (600/300 mg) or tenofovir/emtricitabine (245/200 mg) in HIV-1-infected patients

Markus Bickel; A. Bodtländer; Gaby Knecht; Christoph Stephan; N. von Hentig; Michael Kurowski; Peter Gute; Stephan Klauke; Thomas Lutz

OBJECTIVES To investigate the feasibility and pharmacokinetics of a once-daily regimen of 2000 mg saquinavir mesylate boosted with 100 mg ritonavir. PATIENTS AND METHODS Patients successfully treated with 1000 mg saquinavir boosted with 100 mg ritonavir twice daily together with two nucleoside or nucleotide reverse transcriptase inhibitors [N(t)RTIs] who were switched to 2000 mg saquinavir with 100 mg ritonavir once daily with unchanged N(t)RTI therapy were analysed. CD4 cells, HIV-RNA PCR and metabolic parameters were compared between baseline and 3, 6, 9 and 12 months after the switch. Saquinavir and ritonavir drug levels were measured before and a median of 3 weeks after switching from twice to once daily at 0, 1, 2, 4, 6, 9, 12 and 24 h after intake of the medication. The area under the serum concentration-time curve from 0 to 24 h (AUC(0-24)) was calculated using the trapezoidal rule. RESULTS Eighteen patients (16 males, median age of 41 years) with a median CD4 cell count of 464 cells/mm(3) were analysed. HIV-RNA PCR remained <500 copies/mL for all patients. After switching from 100 mg twice daily to 100 mg once daily, the AUC(0-24) for ritonavir decreased significantly [21 874 to 10 267 ng.h/mL, geometric mean ratio (GMR) = 0.47; P < 0.001], whereas the AUC(0-24) for saquinavir decreased only marginally from 35 000 to 34 490 ng.h/mL (GMR = 0.99; P = 0.426). The CD4 cell count and the fasting metabolic parameters remained unchanged. CONCLUSIONS Once-daily treatment with ritonavir-boosted saquinavir was well tolerated and resulted in similar saquinavir drug exposure despite much lower ritonavir concentrations when compared with a twice-daily dosing schedule.


Journal of the International AIDS Society | 2008

Lipometabolic side-effects of three ritonavir-boosted double protease inhibitor regimens without reverse transcriptase inhibitors

A Wendig; Christoph Stephan; Pavel Khaykin; Markus Bickel; Tessa Lennemann; Gaby Knecht; Thomas Lutz; N von Hentig; Schlomo Staszewski

of results Median baseline characteristics were a patient age of 42 years, male gender (n = 139; 80.4%) and 10.1 years from first HIV-positive test. 158 patients were ART-experienced and received a boosted double PI regimen due to previous RTI-resistance and/or toxicity. Among these, 68 patients previously had a structured treatment interruption and 90 patients have been treated with a PI-sparing ART regimen; 15 patients were ART-naive. Differences for metabolic parameters between groups were not significant. Fiftyeight out of 173 patients received a lipid-lowering agent (LLA) (LOPSAQ n = 42, ATSAQ n = 11, FOSAQ n = 5) and seven (4%) were initiated on a new LLA during the study. Total cholesterol significantly increased over 48 weeks for all groups: 166 mg/dL to 213 mg/dL (LOPSAQ), 168 mg/ dL to 216 mg/dL (ATSAQ) and 161 mg/dl to 235 mg/dl (FOSAQ) after 48 weeks (for all, p < 0.01; ITT-analysis), whereas median triglyceride levels significantly increased only for the LOPSAQ-group (195 mg/dl to 283 mg/dl; p < 0.01), but not for the other two groups (ATSAQ: 161 mg/ dL to 202 mg/dL, p = 0.2; FOSAQ: 130 mg/dl to 220 mg/ dl, p = 0.6). HDLand LDL-cholesterol increased non-significantly in all groups. See Figure 1.


Journal of the International AIDS Society | 2008

Once-daily saquinavir (SAQ)/ritonavir (RTV) (2000/100 mg) with abacavir/lamivudine (600/300 mg) or tenofovir/emtricitabine (245/300 mg) in naïve patients

Markus Bickel; A Bodtlaender; Gaby Knecht; M Kurowski; Stephan Klauke; Thomas Lutz

Poster presentation: Background In the past years, once-daily (QD) dosing of antiretroviral combination therapy has become an increasingly available treatment option for HIV-1+ patients. Methods Open label study in which HIV-1+ patients treated with SAQ/RTV (1000/100 mg BID) and two NRTIs with HIV-RNA-PCR < 50 copies/ml were switched to SAQ/RTV(2000/100 mg QD) with unchanged NRTI-backbone. CD4-cells, HIV-RNA-PCR, SAQ and RTV drug-levels and metabolic parameters were compared. Summary of results 17 patients (15 male, 42 years), median CD4 456 ± 139/micro l were included so far. The median follow-up time is 4 months. The HIV-RNA-PCR remained <50 copies/ml for all patients. Fasting metabolic parameters remained unchanged. The SAQ AUC 0–12 h were significantly higher when given QD vs. BID (median 29,400 vs. 18,500 ng*h/ml; p = 0.009), whereas the Cmin, Cmax and AUC was lower for RTV when given QD vs. BID (7,400 vs. 11,700 ng*h/ml; p = 0.02). Conclusion In this ongoing study SAQ/RTV (2000/100 mg QD) was well tolerated and demonstrated higher SAQ and lower RTV drug levels as compared to the BID dosing schedule. (Table 1 and Figure 1.)


British Journal of Clinical Pharmacology | 2006

A comparison of the steady-state pharmacokinetics of nevirapine in men, nonpregnant women and women in late pregnancy

Nils von Hentig; Amina Carlebach; Peter Gute; Gaby Knecht; Stefan Klauke; Maren Rohrbacher; Hartmut Stocker; Michael Kurowski; Sebastian Harder; Schlomo Staszewski; Annette Haberl


Antiviral Therapy | 2007

Evolution of resistance mutations during low-level viral replication in HIV-1-infected patients treated with zidovudine/lamivudine/abacavir as a first-line regimen

Martin Stürmer; Brenda Dauer; Manfred Moesch; Annette Haberl; Axel Mueller; Leo Locher; Gaby Knecht; Nora Hanke; Hans Wilhelm Doerr; Schlomo Staszewski


Medical Microbiology and Immunology | 2014

Improved virological and immunological efficacy of resistance-guided switch in antiretroviral therapy: a Frankfurt HIV cohort analysis

Timo Wolf; B. Fuß; Pavel Khaykin; Annemarie Berger; Gaby Knecht; Peter Gute; Hans-Reinhard Brodt; S. Goepel; Markus Bickel; M. Stuermer; Christoph Stephan

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Peter Gute

Goethe University Frankfurt

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Christoph Stephan

Goethe University Frankfurt

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Markus Bickel

Goethe University Frankfurt

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Eva Herrmann

Goethe University Frankfurt

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Pavel Khaykin

Goethe University Frankfurt

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Christoph Sarrazin

Goethe University Frankfurt

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Martin Stürmer

Goethe University Frankfurt

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Schlomo Staszewski

Goethe University Frankfurt

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Stefan Zeuzem

Goethe University Frankfurt

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