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753 results on '"Verhoef, Jan"'

10. Acute lymphoblastic leukaemia patients treated with PEGasparaginase develop antibodies to PEG and the succinate linker

Author

Kloos, Robin, van der Sluis, Inge M, Mastrobattista, Enrico, Hennink, Wim, Pieters, Rob, Verhoef, Jan-Jaap, Afd Pharmaceutics, Pharmaceutics, Afd Pharmaceutics, Pharmaceutics, and Pediatrics

Subjects
Drug, Male, Asparaginase, media_common.quotation_subject, Succinic Acid, Polyethylene glycol, acute lymphoblastic leukemia, Pharmacology, Polyethylene Glycols, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, PEG ratio, Medicine, Humans, antibodies, media_common, biology, business.industry, Hematology, Precursor Cell Lymphoblastic Leukemia-Lymphoma, Hypersensitivity reaction, chemistry, 030220 oncology & carcinogenesis, biology.protein, Female, PEGasparaginase, Antibody, business, Linker, Pegfilgrastim, 030215 immunology, medicine.drug
Abstract

Polyethylene glycol (PEG) conjugated asparaginase (PEGasparaginase) is essential for treatment of paediatric acute lymphoblastic leukaemia. We developed an assay identifying antibodies against the PEG-moiety, the linker and the drug itself in patients experiencing hypersensitivity reactions to PEGasparaginase. Eighteen patients treated according to the DCOG ALL-11 protocol, with a neutralizing hypersensitivity reaction to PEGasparaginase to the first PEGasparaginase doses in induction (12 patients) or during intensification after interruption of several months (6 patients) were included. ELISA was used to measure antibodies, coating with the succinimidyl succinate linker conjugated to BSA, PEGfilgrastim and Escherichia coli asparaginase, and using hydrolysed PEGasparaginase and mPEG5,000 for competition. Anti-PEG antibodies were detected in all patients (IgG 100%; IgM 67%) of whom 39% had anti-PEG antibodies exclusively. Pre-existing anti-PEG antibodies were also detected in patients who not previously received a PEGylated therapeutic (58% IgG; 21% IgM). Antibodies against the SS-linker were predominantly detected during induction (50% IgG; 42% IgM). Anti-asparaginase antibodies were detected in only 11% during induction but 94% during intensification. In conclusion, anti-PEG and anti-SS-linker antibodies predominantly play a role in the immunogenic response to PEGasparaginase during induction. Thus, switching to native E. coli asparaginase would be an option for adequate asparaginase treatment.

Published
2020

14. Binding of HIV-1 to Human Follicular Dendritic Cells

Author

Joling, Piet, Bakker, Leendert J., van Wichen, Dick F., de Graaf, Loek, Meerloo, Timo, Visser, Maarten R., van Strijp, Jos A. G., Goudsmit, Jaap, Verhoef, Jan, Schuurman, Henk-Jan, Kamperdijk, Eduard W. A., editor, Nieuwenhuis, Paul, editor, and Hoefsmit, Elisabeth C. M., editor

Published
1993
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36. Identification of resistance and virulence factors in an epidemic Enterobacter hormaechei outbreak strain

Author

Paauw, Armand, Caspers, Martien P.M., Hall, Maurine A. Leverstein-van, Schuren, Frank H.J., Montijn, Roy C., Verhoef, Jan, and Fluit, Ad.C.

Subjects
Enterobacter -- Physiological aspects, Enterobacter -- Genetic aspects, Enterobacter -- Research, Enterobacteriaceae -- Physiological aspects, Enterobacteriaceae -- Genetic aspects, Enterobacteriaceae -- Research, Epidemiology -- Genetic aspects, Epidemiology -- Research, Virulence (Microbiology) -- Genetic aspects, Virulence (Microbiology) -- Research, Biological sciences
Abstract

Bacterial strains differ in their ability to cause hospital outbreaks. Using comparative genomic hybridization, Enterobacter cloacae complex isolates were studied to identify genetic markers specific for Enterobacter cloacae complex outbreak strains. No outbreak-specific genes were found that were common in all investigated outbreak strains. Therefore, the aim of our study was to identify specific genetic markers for an Enterobacter hormaechei outbreak strain (EHOS) that caused a nationwide outbreak in The Netherlands. Most EHOS isolates carried a large conjugative plasmid (pQC) containing genes encoding heavy-metal resistance, mobile elements, pill-associated proteins and exported proteins as well as multiple-resistance genes. Furthermore, the chromosomally encoded high-pathogenicity island (HPI) was highly associated with the EHOS strain. In addition, other DNA fragments were identified that were associated with virulence: three DNA fragments known to be located on a virulence plasmid (pLVPK), as well as phage- and plasmid-related sequences. Also, four DNA fragments encoding putative pili with the most homology to pili of Salmonella enterica were associated with the EHOS. Finally, four DNA fragments encoding putative outer-membrane proteins were negatively associated with the EHOS. In conclusion, resistance and putative virulence genes were identified in the EHOS that may have contributed to increased epidemicity. The high number of genes detected in the EHOS that were related to transferable elements reflects the genomic plasticity of the E. cloacae complex and may explain the emergence of the EHOS in the hospital environment.

Published
2009

39. Enterobacter cloacae outbreak and emergence of quinolone resistance gene in Dutch hospital

Author

Paauw, Armand, Fluit, Ad C., Verhoef, Jan, and Leverstein-van Hall, Maurine A.

Subjects
Enterobacter -- Research, Enterobacteriaceae -- Research, Enterobacteriaceae infections -- Research, Enterobacteriaceae infections -- Genetic aspects, Epidemics -- Research, Epidemics -- Netherlands
Abstract

An outbreak of Enterobacter cloacae infections with variable susceptibility to fluoroquinolones occurred in the University Medical Center Utrecht in the Netherlands in 2002. Our investigation showed that a qnrA1 gene [...]

Published
2006

42. Moraxella (Branhamella) catarrhalis BRO beta-lactamase: a lipoprotein of gram-positive origin?

Author

Bootsma, Hester J., Aerts, Piet C., Posthuma, George, Harmsen, Theo, Verhoef, Jan, Dijk, Hans van, and Mooi, Frits R.

Subjects
Beta lactamases -- Research, Lipoproteins -- Research, Bacteria, Pathogenic -- Research, Biological sciences
Abstract

Moraxella (Branhamella) catarrhalis has emerged as a significant cause of upper respiratory tract infections in children and lower respiratory tract infections in patients with underlying chest disease. Previously, the bro genes coding for M. catarrhalis BRO beta-lactamases have been cloned and sequenced. Research has revealed that BRO is expressed as a 33-kDa lipoprotein related to the inner leaflet of the outer membrane. This is the first lipidated beta-lactamase in a gram-negative species.

Published
1999

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