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Your search keyword '"Bosch, Henk Van Den"' showing total 8 results
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8 results on '"Bosch, Henk Van Den"'

2. Ceramide-binding and activation defines protein-kinase c-Raf as a ceramide-activated protein kinase

Author

Huwiler, Andrea, Brunner, Josef, Hummel, Richard, Vervoordeldonk, Margriet, Stabel, Silvia, Bosch, Henk van den, and Pfeilschifter, Josef

Subjects
Protein kinases -- Research, Interleukin-1 -- Genetic aspects, Cellular signal transduction -- Research, Cytokines -- Research, Science and technology
Abstract

Interleukin 1 is the prototype of an inflammatory cytokine, and evidence suggests that it uses the sphingomyelin pathway and ceramide production to trigger mitogen-activated protein kinase (MAPK) activation and subsequent gene expression required for acute inflammatory processes. To identify downstream signaling targets of ceramide, a radioiodinated photoaffinity labeling analog of ceramide ([125I]3-trifluoromethyl-3-(m-iodophenyl)diazirine-ceramide) was employed. It is observed that ceramide specifically binds to and activates protein kinase c-Raf, leading to a subsequent activation of the MAPK cascade. Ceramide does not bind to any other member of the MAPK module nor does it bind to protein kinase C-[Xi]. These data identify protein kinase c-Raf as a specific molecular target for interleukin 1[Beta]-stimulated ceramide formation and demonstrate that ceramide is a lipid cofactor participating in regulation of c-Raf activity.

Published
1996

3. Acyclovir diphosphate dimyristoylglycerol: a phospholipid prodrug with activity against acyclovir-resistant herpes simplex virus

Author

Hostetler, Karl Y., Parker, Suezanne, Sridhar, C.N., Martin, Michael J., Jui-Lien Li, Stuhmiller, Louise M., Wijk, Gijsbert M.T. van, Bosch, Henk van den, Gardner, Michael F., Aldern, Kathy A., and Richman, Douglas D.

Subjects
Acyclovir -- Physiological aspects, Herpes simplex virus -- Drug therapy, Science and technology
Abstract

The effectiveness of acyclovir (9-((2-hydroxyethoxy)-methyl)guanine, Zovirax) can be revived by preparing acyclovir diphosphate dimyristoylglycerol, an analog of a naturally occurring phospholipid, CDP-diacylglycerol. Deficiency or defect in virally coded thymidine kinase is evident for a majority of virus isolates, resistant to acyclovir. A clinical issue in AIDS patients is herpes simplex viruses mutant infection which is to treatment with acyclovir.

Published
1993

4. Alkyl-dihydroxyacetonephosphate Synthase. Presence and Role of Flavin Adenine Dinucleotide

Author

Vet, Edwin C.J.M. de, Hilkes, Yvonne H.A., Fraaije, Marco W., Bosch, Henk van den, and Groningen Biomolecular Sciences and Biotechnology

Abstract

Alkyl-dihydroxyacetonephosphate synthase is a peroxisomal enzyme involved in ether lipid synthesis. It catalyzes the exchange of the acyl chain in acyl-dihydroxyacetonephosphate for a long chain fatty alcohol, yielding the first ether linked intermediate, i.e. alkyl-dihydroxyacetonephosphate, in the pathway of ether lipid biosynthesis. Although this reaction is not a net redox reaction, the amino acid sequence of the enzyme suggested the presence of a flavin adenine dinucleotide (FAD)-binding domain. In this study we show that alkyl-dihydroxyacetonephosphate synthase contains an essential FAD molecule as cofactor, which is evidenced by fluorescence properties, UV-visible absorption spectra and the observation that the enzyme activity is dependent on the presence of this cofactor in a coupled in vitro transcription/translation assay. Furthermore, we could demonstrate that the FAD cofactor directly participates in catalysis. Upon incubation of the enzyme with the substrate palmitoyl-dihydroxyacetonephosphate, the flavin moiety is reduced, indicating that in this initial step the substrate is oxidized. Stopped flow experiments show that the reduction of the flavin moiety is a monophasic process yielding a oxygen stable, reduced enzyme species. Upon addition of hexadecanol to the reduced enzyme species, the flavin moiety is efficiently reoxidized. A hypothetical reaction mechanism is proposed that is consistent with the data in this paper and with previous studies.

Published
2000

7. Cytosolic phospholipase A<INF>2</INF> activity during the ongoing cell cycle

Author

Rossum, Gerda S.A.T. van, Vlug, Angela S., Bosch, Henk van den, Verkleij, Arie J., and Boonstra, Johannes

Abstract

Cytosolic phospholipase A2 (cPLA2) is of special interest because it selectively releases arachidonic acid from membrane phospholipids. Arachidonic acid has been implicated to play an important role in various cellular responses. Recently arachidonic acid release and prostaglandin synthesis have been shown to be cell cycle dependent and therefore the activity of cPLA2 during the ongoing cell cycle was investigated, using the mitotic shake off method for cell synchronisation. cPLA2 activity was high in mitotic cells and decreased rapidly in the early G1 phase. A strong increase in activity was measured following the G1/S transition in both neuroblastoma and Chinese hamster ovary cells. The changes in activity were not due to a difference in cPLA2 expression but due to phosphorylation of cPLA2. Phosphorylation of cPLA2 occurs through MAPK since the use of a specific MAPK kinase inhibitor and serum depletion of synchronised cells inhibited cPLA2 activity. © 2001 Wiley-Liss, Inc.

Published
2001
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8. Phospholipase A2 Is a Circulating Mediator in Typhoid Fever

Author

Keuter, Monique, Dharmana, Edi, Kullberg, Bart-Jan, Schalkwijk, Casper, Gasem, M. Hussein, Seuren, Liesbeth, Djokomoeljanto, Robert, Dolmans, Wil M. V., Bosch, Henk van den, and van der Meer, Jos W. M

Abstract

Circulating proinflammatory mediators have not been found in studies on typhoid fever, although the patients suffer from a systemic disease with characteristic protracted fever. The 14-kDa group II extracellular phospholipase A2 (PLA2) is induced by interleukin-1 and tumor necrosis factor and may mediate some of the effects of these cytokines. Circulating PLA2 concentrations were measured in 12 typhoid fever patients on various days after admission and after recovery. On admission, mean concentrations of PLA2 were elevated (1444 ± 1560 ng/mL) and decreased gradually and significantly to day 14 (55 ± 48 ng/mL). Patients with complicated disease had significantly higher PLA2 levels on admission. PLA2 was not produced in a lipopolysaccharide-stimulated whole blood culture, indicating that PLA2 originates from other types of cells. These data indicate that PLA2 may be a mediator of disease in protracted inflammatory diseases such as typhoid fever.

Published
1995
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