11 results on '"Stuyver L"'
Search Results
2. Line probe assay for rapid detection of drug-selected mutations in the human immunodeficiency virus type 1 reverse transcriptase gene
- Author
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Stuyver, L, primary, Wyseur, A, additional, Rombout, A, additional, Louwagie, J, additional, Scarcez, T, additional, Verhofstede, C, additional, Rimland, D, additional, Schinazi, R F, additional, and Rossau, R, additional
- Published
- 1997
- Full Text
- View/download PDF
3. Second-generation line probe assay for hepatitis C virus genotyping
- Author
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Stuyver, L, primary, Wyseur, A, additional, van Arnhem, W, additional, Hernandez, F, additional, and Maertens, G, additional
- Published
- 1996
- Full Text
- View/download PDF
4. Comparison of the FilmArray RP, Verigene RV+, and Prodesse ProFLU+/FAST+ multiplex platforms for detection of influenza viruses in clinical samples from the 2011-2012 influenza season in Belgium.
- Author
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Van Wesenbeeck L, Meeuws H, Van Immerseel A, Ispas G, Schmidt K, Houspie L, Van Ranst M, and Stuyver L
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Belgium, Child, Child, Preschool, Female, Humans, Infant, Infant, Newborn, Male, Middle Aged, Nasal Mucosa virology, Prospective Studies, Sensitivity and Specificity, Young Adult, Influenza, Human diagnosis, Molecular Diagnostic Techniques methods, Orthomyxoviridae isolation & purification, Virology methods
- Abstract
Respiratory tract infections (RTIs) are caused by a plethora of viral and bacterial pathogens. In particular, lower RTIs are a leading cause of hospitalization and mortality. Timely detection of the infecting respiratory pathogens is crucial to optimize treatment and care. In this study, three U.S. Food and Drug Administration-approved molecular multiplex platforms (Prodesse ProFLU+/FAST+, FilmArray RP, and Verigene RV+) were evaluated for influenza virus detection in 171 clinical samples collected during the Belgian 2011-2012 influenza season. Sampling was done using mid-turbinate flocked swabs, and the collected samples were stored in universal transport medium. The amount of viral RNA present in the swab samples ranged between 3.07 and 8.82 log10 copies/ml. Sixty samples were concordant influenza A virus positive, and 8 samples were found to be concordant influenza B virus positive. Other respiratory viruses that were detected included human rhinovirus/enterovirus, respiratory syncytial virus, parainfluenza virus type 1, human metapneumovirus, and coronavirus NL63. Twenty-five samples yielded discordant results across the various assays which required further characterization by sequencing. The FilmArray RP and Prodesse ProFLU+/FAST+ assays were convenient to perform with regard to sensitivity, ease of use, and low percentages of invalid results. Although the limit of sensitivity is of utmost importance, many other factors should be taken into account in selecting the most convenient molecular diagnostic assay for the detection of respiratory pathogens in clinical samples.
- Published
- 2013
- Full Text
- View/download PDF
5. A pragmatic approach to HIV-1 drug resistance determination in resource-limited settings by use of a novel genotyping assay targeting the reverse transcriptase-encoding region only.
- Author
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Aitken SC, Bronze M, Wallis CL, Stuyver L, Steegen K, Balinda S, Kityo C, Stevens W, Rinke de Wit TF, and Schuurman R
- Subjects
- Africa, Child, DNA Primers genetics, Developing Countries, Europe, Genotype, Humans, Microbial Sensitivity Tests methods, Plasma virology, RNA, Viral genetics, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA, Drug Resistance, Viral, HIV Infections virology, HIV Reverse Transcriptase genetics, HIV-1 genetics, Molecular Diagnostic Techniques methods
- Abstract
In resource-limited settings (RLS), reverse transcriptase (RT) inhibitors form the backbone of first-line treatment regimens. We have developed a simplified HIV-1 drug resistance genotyping assay targeting the region of RT harboring all major RT inhibitor resistance mutation positions, thus providing all relevant susceptibility data for first-line failures, coupled with minimal cost and labor. The assay comprises a one-step RT-PCR amplification reaction, followed by sequencing using one forward and one reverse primer, generating double-stranded coverage of RT amino acids (aa) 41 to 238. The assay was optimized for all major HIV-1 group M subtypes in plasma and dried blood spot (DBS) samples using a panel of reference viruses for HIV-1 subtypes A to D, F to H, and circulating recombinant form 01_AE (CRF01_AE) and applied to 212 clinical plasma samples and 25 DBS samples from HIV-1-infected individuals from Africa and Europe. The assay was subsequently transferred to Uganda and applied locally on clinical plasma samples. All major HIV-1 subtypes could be detected with an analytical sensitivity of 5.00E+3 RNA copies/ml for plasma and DBS. Application of the assay on 212 clinical samples from African subjects comprising subtypes A to D, F to H (rare), CRF01_AE, and CRF02_AG at a viral load (VL) range of 6.71E+2 to 1.00E+7 (median, 1.48E+5) RNA copies/ml was 94.8% (n = 201) successful. Application on clinical samples in Uganda demonstrated a comparable success rate. Genotyping of clinical DBS samples, all subtype C with a VL range of 1.02E+3 to 4.49E+5 (median, 1.42E+4) RNA copies/ml, was 84.0% successful. The described assay greatly reduces hands-on time and the costs required for genotyping and is ideal for use in RLS, as demonstrated in a reference laboratory in Uganda and its successful application on DBS samples.
- Published
- 2013
- Full Text
- View/download PDF
6. Metabolism of the anti-hepatitis C virus nucleoside beta-D-N4-hydroxycytidine in different liver cells.
- Author
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Hernandez-Santiago BI, Beltran T, Stuyver L, Chu CK, and Schinazi RF
- Subjects
- Alkaline Phosphatase chemistry, Animals, Biotransformation, Cell Line, Chromatography, High Pressure Liquid, Half-Life, Haplorhini, Hepatocytes metabolism, Humans, In Vitro Techniques, Liver cytology, Mass Spectrometry, Nucleosides metabolism, Antiviral Agents metabolism, Cytidine analogs & derivatives, Cytidine metabolism, Hepacivirus drug effects, Liver metabolism
- Abstract
Beta-D-N4-hydroxycytidine (NHC) was found to have selective anti-hepatitis C virus (HCV) activity in the HCV replicon system (clone A). The intracellular metabolism of tritiated NHC was investigated in the HCV replicon system, Huh-7 cells, HepG2 cells, and primary human hepatocytes. Incubation of cells with 10 microM radiolabeled NHC demonstrated extensive and rapid phosphorylation in all liver cells. Besides the 5'-mono, -di-, and -triphosphate metabolites of NHC, other metabolites were characterized. These included cytidine and uridine mono-, di-, and triphosphates. UTP was the predominant early metabolite in Huh-7 cells and primary human hepatocytes, suggesting deamination of NHC as the primary catabolic pathway. The intracellular half-lives of radiolabeled NHC-triphosphate and of CTP and UTP derived from NHC incubation in Huh-7 cells were calculated to be 3.0 +/- 1.3, 10.4 +/- 3.3, and 13.2 +/- 3.5 h (means +/- standard deviations), respectively. Studies using monkey and human whole blood demonstrated more-rapid deamination and oxidation in monkey cells than in human cells, suggesting that NHC may not persist long enough in plasma to be delivered to liver cells.
- Published
- 2004
- Full Text
- View/download PDF
7. DPC 817: a cytidine nucleoside analog with activity against zidovudine- and lamivudine-resistant viral variants.
- Author
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Schinazi RF, Mellors J, Bazmi H, Diamond S, Garber S, Gallagher K, Geleziunas R, Klabe R, Pierce M, Rayner M, Wu JT, Zhang H, Hammond J, Bacheler L, Manion DJ, Otto MJ, Stuyver L, Trainor G, Liotta DC, and Erickson-Viitanen S
- Subjects
- Animals, Anti-HIV Agents pharmacokinetics, Anti-HIV Agents pharmacology, Cytidine chemical synthesis, Cytidine pharmacokinetics, HIV Infections drug therapy, HIV Reverse Transcriptase drug effects, HIV-1 genetics, Humans, Lamivudine pharmacokinetics, Lamivudine pharmacology, Macaca mulatta, Nucleosides chemical synthesis, Nucleosides chemistry, Nucleosides pharmacokinetics, Nucleosides pharmacology, Reverse Transcriptase Inhibitors pharmacokinetics, Reverse Transcriptase Inhibitors pharmacology, Zalcitabine analogs & derivatives, Zalcitabine chemical synthesis, Zalcitabine pharmacokinetics, Zidovudine pharmacokinetics, Zidovudine pharmacology, Cytidine analogs & derivatives, Cytidine pharmacology, Drug Resistance, Viral, HIV-1 drug effects, Zalcitabine pharmacology
- Abstract
Highly active antiretroviral therapy (HAART) is the standard treatment for infection with the human immunodeficiency virus (HIV). HAART regimens consist of protease inhibitors or nonnucleoside reverse transcriptase inhibitors combined with two or more nucleoside reverse transcriptase inhibitors (NRTIs). DPC 817, 2',3'-didehydro-2',3'-dideoxy-5-fluorocytidine (PSI 5582 D-D4FC) is a potent inhibitor of HIV type 1 replication in vitro. Importantly, DPC 817 retains activity against isolates harboring mutations in the reverse transcriptase gene that confer resistance to lamivudine (3TC) and zidovudine (AZT), which are frequent components of initial HAART regimens. DPC 817 combines this favorable resistance profile with rapid uptake and conversion to the active metabolite DPC 817-triphosphate, which has an intracellular half-life of 13 to 17 h. Pharmacokinetics in the rhesus monkey suggest low clearance of parent DPC 817 and a plasma half-life longer than that of either AZT or 3TC. Together, these properties suggest that DPC 817 may be useful as a component of HAART regimens in individuals with resistance to older NRTI agents.
- Published
- 2002
- Full Text
- View/download PDF
8. Prevalence and characteristics of multinucleoside-resistant human immunodeficiency virus type 1 among European patients receiving combinations of nucleoside analogues.
- Author
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Van Vaerenbergh K, Van Laethem K, Albert J, Boucher CA, Clotet B, Floridia M, Gerstoft J, Hejdeman B, Nielsen C, Pannecouque C, Perrin L, Pirillo MF, Ruiz L, Schmit JC, Schneider F, Schoolmeester A, Schuurman R, Stellbrink HJ, Stuyver L, Van Lunzen J, Van Remoortel B, Van Wijngaerden E, Vella S, Witvrouw M, Yerly S, De Clercq E, Destmyer J, and Vandamme AM
- Subjects
- Amino Acid Substitution, CD4 Lymphocyte Count, Codon, Drug Resistance, Microbial, Drug Resistance, Multiple genetics, Drug Therapy, Combination, Europe, Female, Gene Frequency, Genotype, HIV Infections drug therapy, HIV Infections immunology, HIV Reverse Transcriptase genetics, HIV Reverse Transcriptase metabolism, HIV-1 enzymology, HIV-1 genetics, Humans, Male, Microbial Sensitivity Tests, Mutagenesis, Insertional, Nucleosides chemistry, Nucleosides pharmacology, Nucleosides therapeutic use, Phenotype, Anti-HIV Agents pharmacology, HIV Infections virology, HIV-1 drug effects
- Abstract
The prevalence and the genotypic and phenotypic characteristics of multinucleoside-resistant (MNR) human immunodeficiency virus type 1 (HIV-1) variants in Europe were investigated in a multicenter study that involved centers in nine European countries. Study samples (n = 363) collected between 1991 and 1997 from patients exposed to two or more nucleoside analogue reverse transcriptase inhibitors (NRTIs) and 274 control samples from patients exposed to no or one NRTI were screened for two marker mutations of multinucleoside resistance (the Q151M mutation and a mutation with a 2-amino-acid insertion at codon 69, T69S-XX). Q151M was identified in six of the study samples (1. 6%), and T69S-XX was identified in two of the study samples (0.5%; both of them T69S-SS), but both patterns were absent among control samples. Non-NRTI (NNRTI)-related changes were observed in viral strains from two patients, which displayed the Q151M resistance pattern, although the patients were NNRTI naive. The patients whose isolates displayed multinucleoside resistance had received treatment with zidovudine and either didanosine, zalcitabine, or stavudine. Both resistance patterns conferred broad cross-resistance to NRTIs in vitro and a poor response to treatment in vivo. MNR HIV-1 is found only among multinucleoside-experienced patients. Its prevalence is low in Europe, but it should be closely monitored since it seriously limits treatment options.
- Published
- 2000
- Full Text
- View/download PDF
9. Line probe assay for monitoring drug resistance in hepatitis B virus-infected patients during antiviral therapy.
- Author
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Stuyver L, Van Geyt C, De Gendt S, Van Reybroeck G, Zoulim F, Leroux-Roels G, and Rossau R
- Subjects
- Amino Acid Sequence, Antiviral Agents therapeutic use, Base Sequence, DNA, Viral genetics, DNA-Directed DNA Polymerase chemistry, Drug Resistance, Microbial genetics, Hepatitis B drug therapy, Hepatitis B virus enzymology, Humans, Molecular Sequence Data, Mutation, Oligonucleotide Probes, Plasmids genetics, Polymerase Chain Reaction methods, Sequence Analysis, DNA, Antiviral Agents pharmacology, DNA-Directed DNA Polymerase genetics, Hepatitis B virology, Hepatitis B virus drug effects, Hepatitis B virus genetics
- Abstract
Since the introduction of antiviral compounds such as lamivudine and famciclovir in the treatment schedules of patients with chronic hepatitis B virus (HBV) infection, the accumulation of a variety of mutations in the HBV polymerase gene has been observed. The selection of these mutations is generally considered the cause of viral nonresponsiveness and treatment failure. Therefore, the detection of these mutations is of clinical importance. Previously genotyped HBV strains isolated from treated and untreated patients were amplified with primers specific for the HBV polymerase region from amino acids 465 to 562. Amplified products were cloned into plasmid vectors. The clones were used as reference strains. A set of 38 highly specific oligonucleotide probes covering three different codon positions, L528M, M552V/I, and V/L/M555I, were selected. These probes were applied as 19 different lines on a membrane strip. The strips were then hybridized with PCR fragments from the reference panel, revealing the amino acids at the three codon positions simultaneously for each clone. PCR products generated from two patients infected with HBV genotypes A and C, respectively, and treated with nucleoside analogs were analyzed on these strips. A gradual increase in genetic HBV polymerase complexity was observed in follow-up samples compared to that in pretreatment samples. Additional analysis of HBV polymerase DNA fragments in recombinant plasmid clones demonstrated the existence of (i) clones with double mutations, (ii) clones with single mutations at either codon 528, 552, or 555, and (iii) the simultaneous occurrence of two or more viral populations within one sample. This line probe assay detected the complex quasispecies nature of HBV and provided some insight into the dynamics of resistance mutations.
- Published
- 2000
- Full Text
- View/download PDF
10. Sequence diversity of the reverse transcriptase of human immunodeficiency virus type 1 from untreated Brazilian individuals.
- Author
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Brindeiro R, Vanderborght B, Caride E, Correa L, Oravec RM, Berro O, Stuyver L, and Tanuri A
- Subjects
- Base Sequence, Codon, Drug Resistance, Microbial, Genotype, HIV-1 classification, HIV-1 drug effects, HIV-1 genetics, Humans, Molecular Sequence Data, Phylogeny, Zidovudine pharmacology, HIV Reverse Transcriptase chemistry, HIV Seropositivity virology
- Abstract
The presence of human immunodeficiency virus type 1 (HIV-1) bearing mutations resistant to nucleosidic inhibitors of the viral reverse transcriptase (RT) derived from HIV-seropositive asymptomatic and untreated volunteer blood donors was examined. The RT amplicons of 32 specimens were analyzed by using a reverse hybridization line probe assay technique that detects resistance against zidovudine (3'-azido-3'-deoxythymidine [AZT], didanosine (2',3'-dideoxyinosine [ddI], zalcitabine (2',3'-dideoxycytidine [ddC]), and lamivudine ((-)-beta-L-2',3'-dideoxy-3'-thiacytidine [3TC]) at amino acid positions 41, 69, 70, 74, 184, and 215 of the HIV RT. One sample (brp004, subtype B) showed an AZT resistance secondary mutation at position K70R. Fifteen specimens revealed one or more sites of nonreactivity to both wild-type- and mutant-specific probes (dual nonreactivity). Samples were also submitted to RT direct sequencing and phylogenetic analysis. Nine of 32 specimens belonged to non-B subtypes (C, D, F, and F/B or B/F mosaics). Three of these non-B isolates, named brp004, brp063, and brp069, revealed three other relevant AZT resistance mutations-a T215F mutation and two M41L mutations, respectively-hidden by the nonreactivity to line probe assay strips on the respective codon regions. The isolate brp004 also carried a D67N AZT resistance mutation revealed by direct sequencing. No nonnucleosidic RT inhibitor-resistant mutation was found. The analysis revealed a frequency of 2.26 x 10(-4) mutations per nucleotide for independent samples related to RT resistance. These findings emphasize the magnitude of naturally occurring reservoirs of drug-resistant virus among untreated HIV-1-positive individuals in Brazil.
- Published
- 1999
- Full Text
- View/download PDF
11. Antigenic diversity of hepatitis B virus strains of genotype F in Amerindians and other population groups from Venezuela.
- Author
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Blitz L, Pujol FH, Swenson PD, Porto L, Atencio R, Araujo M, Costa L, Monsalve DC, Torres JR, Fields HA, Lambert S, Van Geyt C, Norder H, Magnius LO, Echevarría JM, and Stuyver L
- Subjects
- Amino Acid Substitution, Female, Genotype, Hepatitis B epidemiology, Hepatitis B ethnology, Hepatitis B Surface Antigens immunology, Hepatitis B virus classification, Hepatitis B virus immunology, Humans, Pregnancy, Pregnancy Complications, Infectious virology, Sequence Analysis, Venezuela epidemiology, Antigenic Variation, Hepatitis B virology, Hepatitis B Surface Antigens genetics, Hepatitis B virus genetics, Indians, South American
- Abstract
The adw4 subtype of hepatitis B virus (HBV) belongs to a unique genomic group (genotype F) representing the original HBV strains from the New World. Data regarding the prevalence of this subtype among HBV carriers in South America are, however, scarce, and those concerning HBV genotype F are based on only a few samples from Latin America. In this study, serum samples were obtained from 141 hepatitis B surface antigen (HBsAg) carriers from Amerindians and urban populations from Venezuela. The HBsAg subtype was identified with monoclonal antibodies in 105 samples, and the HBV genotype was identified by reverse-phase hybridization with DNA fragments in 58 samples. The adw4 subtype was highly prevalent in the population studied (75%); among the Amerindians, the prevalence was 97%. The adw2 subtype was also present (10%), while other subtypes (ayw3 and ayw4) were only occasionally found. The HBV subtype was associated with the expected genotype in most cases (80%), and thus genotype F was highly prevalent. Sequencing of viral strains that gave genotypes unpredicted by the HBsAg subtyping confirmed seven of them as belonging to not previously described genotype-subtype associations: namely, adw2 and ayw4 within genotype F.
- Published
- 1998
- Full Text
- View/download PDF
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