Enzymes of purine nucleotide metabolism in human lymphocytes

Laarhoven, J. P. R. M. van; Spierenburg, Gerrit; Bruyn, C. H. M. M. de

doi:10.1016/0022-1759(80)90293-8

Cited by 39 publications

(6 citation statements)

References 11 publications

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“…For detailed description of enzyme assays, refer to original publications for 5′ nucleotidase (Van Laarhoven et al , 1980), adenosine deaminase and purine nucleoside phosphorylase (Hopkinson et al , 1969), ribonucleotide reductase (Lepoivre et al , 1990), deoxycytidine kinase and deoxycytidine deaminase (Ruiz van Haperen et al , 1993). Deoxycytidine kinase assays were performed using 3 H‐CdA.…”

Section: Methodsmentioning

confidence: 99%

Common resistance mechanisms to deoxynucleoside analogues in variants of the human erythroleukaemic line K562

et al. 1999

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Summary. Resistant variants of the human leukaemic line K562 were developed using selection with the deoxynucleoside analogues cytosine arabinoside, 2-chlorodeoxyadenosine, udarabine and gemcitabine. The resistant lines displayed a high degree of cross resistance to all deoxynucleoside analogues, with little or no cross resistance to other agents. There was a profound accumulation defect of all nucleoside analogues in the resistant variants but no signi®cant defect in nucleoside transport in any of the variants. 5H nucleotidase activity was strongly increased and deoxycytidine kinase activity was moderately reduced in all of the resistant variants, resulting in reduced accumulation of triphosphate analogues. In addition a deletion in one of the alleles of the deoxycytidine kinase was detected in thē udarabine-resistant line. Ribonucleotide reductase activity was found to be strongly increased in the gemcitabineselected line and purine nucleoside phosphorylase was increased in the 2-chlorodeoxyadenosine-selected line. Free nucleotide pools were increased in the 2-chlorodeoxyadenosineselected line. There was no expression of the mdr1 gene by the resistant lines. Karyotypic analysis and FISH experiments using a 6q21 speci®c probe showed alterations in the 6(q16-q22) region which contains the 5 H -nucleotidase gene. Early events in the activation and degradation of deoxynucleoside analogues appear to constitute common mechanisms of resistance to these compounds.

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Section: Methodsmentioning

confidence: 99%

Common resistance mechanisms to deoxynucleoside analogues in variants of the human erythroleukaemic line K562

et al. 1999

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“…For the HPLC procedure, the enzyme assays were performed the next day and the supernatants were stored at -20°C until the HPLC separation. The enzyme assays, the TLC separation meth ods and the calculation of specific enzyme ac tivities were carried out essentially according to procedures published previously [18]. PNP activity was determined from the conver sion of hypoxanthine to inosine:…”

Section: Isolation O F Mononuclear Cells From Peripheral Bloodmentioning

confidence: 99%

Purine enzyme activities in peripheral blood mononuclear cells: comparison of a new non-radiochemical high-performance liquid chromatography procedure and a radiochemical thin-layer chromatography procedure

Stolk

Abreu

Boerbooms

et al. 1995

Journal of Chromatography B: Biomedical Sciences and Applicatio

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Purine enzyme activities are usually assayed by radiochemical procedures and often TLC is part of the separation method. In screening patients with rheumatic diseases, these procedures have shown disadvantages like a relatively large coefficient of variation (C.V.) and time-instability. We describe a non-radiochemical reversed-phase HPLC micro-method with UV detection for measurement of activities of purine S'-nuclcotidase (5'NT; EC 3.1.3.5), purine nucleoside phosphorylase (PNP; EC 2.4.2.1) and hypoxanthine guanine phosphoribosyltransferase (HGPRT; EC 2.4.2.8) in human peripheral blood mononuclear cells (PBMC). The HPLC procedure is compared with the radiochemical TLC procedure by testing both with a 5'NT and a PNP assay. Reproducibility is tested with 14 healthy controls in each procedure. Short-term and long-term time-stability is tested by comparing enzyme activities measured immediately after preparation of the PBMC (week 0) with those found after freezing and storage at " 20°C for a maximum of 10 weeks. The HPLC procedure is preferable to the radiochemical TLC procedure because it shows significantly better reproducibility and better time-stability and in addition is non-radiochemical and less time-consuming.

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“…The diagnostic significance and biologic role of these epitopes are under investigation. Patients with SLE and SLE-overlap syndromes often produce autoantibodies directed to UiRNA-associated proteins [1]. In this study we characterized human antibody fragments to UiRNA-associated autoantigens selected from a synthetic combinatorial library and a patient-derived combinatorial spleen library.…”

Section: Sle Epit0pesmentioning

confidence: 99%

“…In the present study, sera from healthy controls (n =85) and patients with AS (n=54), rheumatoid arthritis (RA, n = 24), psoriatic arthritis (PA, n = 24), systemic lupus erythematosus (SLE, n=24) and reactive arthritis after Yersinia enterocolitica infection (ReA, n = 20) were analyzed. Antibodies to all known Klebsiella serotypes were detected by ELISA (1). ELISA specificity was shown by the lack of reactivity with non capsulated Klebsiella mutants and other Enterobacteriaceae.…”

Section: Ii31 Neurological Dysfunctions Associated With Anti-phosphmentioning

confidence: 99%

15th European Workshop for Rheumatology Research

1995

Clin Rheumatol

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Enzymes of purine nucleotide metabolism in human lymphocytes

Cited by 39 publications

References 11 publications

Common resistance mechanisms to deoxynucleoside analogues in variants of the human erythroleukaemic line K562

Common resistance mechanisms to deoxynucleoside analogues in variants of the human erythroleukaemic line K562

Purine enzyme activities in peripheral blood mononuclear cells: comparison of a new non-radiochemical high-performance liquid chromatography procedure and a radiochemical thin-layer chromatography procedure

15th European Workshop for Rheumatology Research

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