152 results on '"de Abreu RA"'
Search Results
2. Purine enzymes in patients with rheumatoid arthritis treated with methotrexate. (Extended Report)
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van Ede, AE, Laan, RFJM, De Abreu, RA, Stegeman, ABJ, and van de Putte, LBA
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Drug therapy ,Physiological aspects ,Dosage and administration ,Rheumatoid arthritis -- Drug therapy -- Physiological aspects ,Methotrexate -- Dosage and administration -- Physiological aspects ,Purines -- Physiological aspects - Abstract
Objectives: To study (a) purine metabolism during treatment with methotrexate (MTX) in patients with rheumatoid arthritis (RA) and (b) the relation of purine metabolism with efficacy and toxicity of MTX [...]
- Published
- 2002
3. Pitfalls in the determination of mutant alleles of the thiopurine methyltransferase gene
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Brouwer, C, Marinaki, AM, Lambooy, LHJ, Duley, JA, Shobowale-Bakre, M, and De Abreu, RA
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- 2001
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4. AB0061 Circulating adenosine levels after initiation of methotrexate and anti-tnf therapy in ra
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Barrera, P, primary, Van Ede, AE, additional, Creemers, M, additional, Laan, RF, additional, De Abreu, RA, additional, and Van de Putte, LB, additional
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- 2001
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5. The Pyruvate-Dehydrogenase Complex from Azotobacter vinelandii. 3. Stoichiometry and Function of the Individual Components
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Cees Veeger, Grande Hj, de Kok A, de Abreu Ra, and Bresters Tw
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Conformational change ,Protein Conformation ,Stereochemistry ,Pyruvate Dehydrogenase Complex ,Biochemistry ,chemistry.chemical_compound ,Moiety ,Molecule ,Magnesium ,Pyruvates ,Spin label ,chemistry.chemical_classification ,Manganese ,Binding Sites ,biology ,Chemistry ,Electron Spin Resonance Spectroscopy ,NAD ,biology.organism_classification ,Pyruvate dehydrogenase complex ,Models, Structural ,Kinetics ,Enzyme ,Azotobacter vinelandii ,Ethylmaleimide ,Azotobacter ,Thiamine Pyrophosphate ,Thiamine pyrophosphate ,Protein Binding - Abstract
Labelling studies with N-ETHYLMALEIMIDE SHOW THAT EITHER IN THE PRESENCE OF Mg2+, thiamine pyrophosphate (TPP) and pyruvate or in the presence of NADH the overall activity of the pyruvate dehydrogenase complex from Azotobacter vinelandii is inhibited without much inhibition of the partial reactions. The complex undergoes a conformational change upon incubation with NADH. The inhibition by bromopyruvate is less specific. Specific incorporation of a fluorescent maleimide derivative was observed on the two transacetylase isoenzymes. Binding studies with a similar spin label analogue show that 3 molecules/FAD are incorporated by incubation of pyruvate, Mg2+ and TPP, whereas 2 molecules/FAD are incorporated via incubation with NADH. The spin label spectra support the idea that in the complex the active centres of the component enzymes are connected by rapid rotation of the lipoyl moiety. Three acetyl groups are incorporated in the complex by incubation with [2-14C]pyruvate. Time-dependent incorporation supports the view that the two transacetylase isoenzymes react in non-identical ways with the pyruvate dehydrogenase components of the complex. The results show that the complex contains 2 low-molecular-weight transacetylase molecules and 4 molecules of the high-molecular-weight isoenzyme. Mn2+-binding studies show that the complex binds 10 ions, with different affinities. 2 Mn2+ ions are bound with a 20-fold higher affinity than the remaining 8 Mn2+ ions. The latter 8 ions bind with equal affinities and are thought to reflect binding to the pyruvate dehydrogenase components of the complex. It is concluded that the complex contains 8 pyruvate dehydrogenase molecules, 4 high-molecular-weight transacetylase molecules, 2 low-molecular-weight transacetylase molecules and 1 dimeric (2-FAD-containing) symmetric molecule of lipoamide dehydrogenase. Evidence comes from pyruvate-dependent inactivation and labelling studies that the pyruvate dehydrogenase components contain either an - SH group or an S-S bridge which participates in the hydroxyethyl transfer to the transacetylase components.
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- 1975
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6. 6-Mercaptopurine: Oral administration and i.v. bolus injections in dogs
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Schouten, Tj, De Abreu, Ra, Schretlen, Edam, de Bruyn, Chmm, van der Kleijn, E., Oosterbaan, Mjm, and de Vaan, Gam
- Abstract
6-Mercaptopurine (6MP) levels in serum of dogs were studied after long-term oral administration and intravenous injection. During long-term daily oral administration of 50 mg of 6MP, more or less constant levels of 6MP have been found after 1-3 weeks. After stopping administration of the drug, 6MP concentrations remained constant for a further period of 3-6 weeks and then declined within 1-2 weeks below the limit of detection. I.v. bolus injections of 50 mg of 6MP resulted in concentration v. time curves which fitted into an open two-compartment pharmacokinetic model. Half-life times were in a range of 13-21 and 125-151 min, respectively. Peak concentrations were from 2,500 to 10,500 nmol/l. Our data on i.v. push injections with a customary clinical dose revealed peak concentrations which were low in comparison to the concentrations used in in vitro studies by Tidd and Paterson to achieve maximal cell-kill. Moreover, the half-life times of the 6MP after i.v. bolus injections are short, so prolonged high plasma concentrations are not obtained by i.v. bolus injections. We suggest that prolonged infusions of 6MP at relatively high dose rates should result in higher and persisting plasma concentrations and so should promise a more potent antitumour activity.
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- 1985
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7. Biphasic Effect of Adenosine on Cell Growth and Cell Cycle of Human Lymphoid Cell Lines
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de Bruyn Ch, van Zandvoort Pm, Bakkeren Ja, van Laarhoven Jp, van der Kraan Pm, and De Abreu Ra
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Cell culture ,Cell growth ,Chemistry ,medicine ,Cell cycle ,Adenosine ,Cell biology ,medicine.drug - Published
- 1986
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8. Inhibition of 3H-Thymidine Incorporation by Guanosine and Deoxyguanosine in Human Lymphoid Cells
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van Laarhoven Jp, Bakkeren Ja, De Abreu Ra, van der Kraan Pm, de Bruyn Ch, and van Zandvoort Pm
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chemistry.chemical_compound ,chemistry ,Kinetics ,DNA replication ,Deoxyguanosine ,Guanosine ,Tritium ,Radioisotope dilution technique ,Thymidine ,Molecular biology ,Thymidine incorporation - Published
- 1986
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9. Sugar-sweetened beverage consumption in Thailand: Determinants and variation across socioeconomic status.
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Thiboonboon K, Lourenco RA, Church J, and Goodall S
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- Humans, Thailand, Male, Female, Adult, Middle Aged, Young Adult, Adolescent, Feeding Behavior, Health Behavior, Aged, Socioeconomic Factors, Sugar-Sweetened Beverages statistics & numerical data, Social Class
- Abstract
Objectives: Reducing consumption of sugar-sweetened beverages (SSBs) is a primary public health goal in Thailand, but information on the characteristics of SSB consumers remains limited. This study aims to gain knowledge about the characteristics of SSB consumers in Thailand., Study Design: Secondary analysis of survey data., Methods: The study used data from the Health Behaviour of Population Survey conducted by Thailand's National Statistics Office between February and May 2021. SSB consumption was sourced from a survey question about the consumption of prepackaged sugar-sweetened non-alcoholic beverages. The influence of demographic, socioeconomic, behavioural, habitual, and health factors on mean daily intake and daily consumption was assessed using a two-part model and logistic regression analysis, respectively. Decomposition analysis was conducted to understand how the impact of these factors affecting SSB consumption varied across socioeconomic groups., Results: Frequent SSB consumers exhibited various unhealthy behaviours, including smoking, unhealthy food consumption, low physical activity, and making food selections driven by appetitive motivations. Although higher socioeconomic status was associated with greater consumption of SSBs, it stabilised at elevated income levels. Increased SSB consumption in higher socioeconomic groups was linked to mixed eating habits, being overweight, and occasional drinking, while in lower socioeconomic groups, it was associated with unhealthy behaviours like smoking, regular alcohol drinking, appetitive food choices, and low physical activity., Conclusions: SSB consumption in Thailand is multifactorial, varying by socioeconomic status. These insights are crucial for policy formation aimed at reducing SSB consumption in the country. Policymakers should explore interventions that address overall unhealthy behaviours alongside those targeting overconsumption of SSBs., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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10. An Economic Analysis of SC24 in Canada: A Randomized Study of SBRT Compared With Conventional Palliative RT for Spinal Metastases.
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Kerba M, Lourenco RA, Sahgal A, Cardet RF, Siva S, Ding K, Myrehaug SD, Masucci GL, Brundage M, and Parulekar WR
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- Humans, Canada, Male, Female, Cancer Pain radiotherapy, Cancer Pain economics, Cancer Pain etiology, Middle Aged, Aged, Radiosurgery economics, Cost-Benefit Analysis, Spinal Neoplasms secondary, Spinal Neoplasms radiotherapy, Spinal Neoplasms surgery, Spinal Neoplasms economics, Spinal Neoplasms mortality, Palliative Care economics, Markov Chains, Quality of Life, Quality-Adjusted Life Years
- Abstract
Purpose: The Canadian Cancer Trials Group (CCTG) Symptom Control 24 protocol (SC.24) was a multicenter randomized controlled phase 2/3 trial conducted in Canada and Australia. Patients with painful spinal metastases were randomized to either 24 Gy/2 stereotactic body radiation therapy (SBRT) or 20 Gy/5 conventional external beam radiation therapy (CRT). The study met its primary endpoint and demonstrated superior complete pain response rates at 3 months following SBRT (35%) versus CRT (14%). SBRT planning and delivery is resource intensive. Given its benefits in SC.24, we performed an economic analysis to determine the incremental cost-effectiveness of SBRT compared with CRT., Methods and Materials: The trial recruited 229 patients. Cost-effectiveness was assessed using a Markov model taking into account observed survival, treatments costs, retreatment, and quality of life over the lifetime of the patient. The EORTC-QLU-C10D was used to determine quality of life values. Transition probabilities for outcomes were from available patient data. Health system costs were from the Canadian health care perspective and were based on 2021 Canadian dollars (CAD). The incremental cost-effectiveness ratio (ICER) was expressed as the ratio of incremental cost to quality-adjusted life years (QALY). The impact of parameter uncertainty was investigated using deterministic and probabilistic sensitivity analyses., Results: The base case for SBRT compared with CRT had an ICER of $9,040CAD per QALY gained. Sensitivity analyses demonstrated that the ICER was most sensitive to variations in the utility assigned to "No local failure" ($5,457CAD to $241,051CAD per QALY), adopting low and high estimates of utility and the cost of the SBRT (ICERs ranging from $7345-$123,361CAD per QALY). It was more robust to variations in assumptions around survival and response rate., Conclusions: SBRT is associated with higher upfront costs than CRT. The ICER shows that, within the Canadian health care system, SBRT with 2 fractions is likely to be more cost-effective than CRT., (Copyright © 2024 Elsevier Inc. All rights reserved.)
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- 2024
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11. Economic Evaluations of Obesity-Targeted Sugar-Sweetened Beverage (SSB) Taxes-A Review to Identify Methodological Issues.
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Thiboonboon K, Lourenco RA, Cronin P, Khoo T, and Goodall S
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- Humans, Public Health economics, Quality-Adjusted Life Years, Cost-Benefit Analysis, Obesity economics, Obesity etiology, Obesity prevention & control, Sugar-Sweetened Beverages adverse effects, Sugar-Sweetened Beverages economics, Taxes economics
- Abstract
Introduction: Economic evaluations of public health interventions like sugar-sweetened beverage (SSB) taxes face difficulties similar to those previously identified in other public health areas. This stems from challenges in accurately attributing effects, capturing outcomes and costs beyond health, and integrating equity effects. This review examines how these challenges were addressed in economic evaluations of SSB taxes., Methods: A systematic review was conducted to identify economic evaluations of SSB taxes focused on addressing obesity in adults, published up to February 2021. The methodological challenges examined include measuring effects, valuing outcomes, assessing costs, and incorporating equity., Results: Fourteen economic evaluations of SSB taxes were identified. Across these evaluations, estimating SSB tax effects was uncertain due to a reliance on indirect evidence that was less robust than evidence from randomised controlled trials. Health outcomes, like quality-adjusted life years, along with a healthcare system perspective for costs, dominated the evaluations of SSB taxes, with a limited focus on broader non-health consequences. Equity analyses were common but employed significantly different approaches and exhibited varying degrees of quality., Conclusion: Addressing the methodological challenges remains an issue for economic evaluations of public health interventions like SSB taxes, suggesting the need for increased attention on those issues in future studies. Dedicated methodological guidelines, in particular addressing the measurement of effect and incorporation of equity impacts, are warranted., Competing Interests: Declaration of interest statement The authors of this manuscript declare that they have no potential conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)
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- 2024
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12. Healthcare Resource Utilization and Cost Associated with Allogeneic Hematopoietic Stem Cell Transplantation: A Scoping Review.
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Kim NV, McErlean G, Yu S, Kerridge I, Greenwood M, and Lourenco RA
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- Humans, Transplantation, Homologous economics, Patient Acceptance of Health Care statistics & numerical data, Health Resources economics, Health Resources statistics & numerical data, Hematopoietic Stem Cell Transplantation economics, Health Care Costs statistics & numerical data
- Abstract
This scoping review summarizes the evidence regarding healthcare resource utilization (HRU) and costs associated with allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study was conducted in accordance with the Joanne Briggs Institute methodology for scoping reviews. The PubMed, Embase, and Health Business Elite Electronic databases were searched, in addition to grey literature. The databases were searched from inception up to November 2022. Studies that reported HRU and/or costs associated with adult (≥18 years) allo-HSCT were eligible for inclusion. Two reviewers independently screened 20% of the sample at each of the 2 stages of screening (abstract and full text). Details of the HRU and costs extracted from the study data were summarized, based on the elements and timeframes reported. HRU measures and costs were combined across studies reporting results defined in a comparable manner. Monetary values were standardized to 2022 US Dollars (USD). We identified 43 studies that reported HRU, costs, or both for allo-HSCT. Of these studies, 93.0% reported on costs, 81.4% reported on HRU, and 74.4% reported on both. HRU measures and cost calculations, including the timeframe for which they were reported, were heterogeneous across the studies. Length of hospital stay was the most frequently reported HRU measure (76.7% of studies) and ranged from a median initial hospitalization of 10 days (reduced-intensity conditioning [RIC]) to 73 days (myeloablative conditioning). The total cost of an allo-HSCT ranged from $63,096 (RIC) to $782,190 (double umbilical cord blood transplantation) at 100 days and from $69,218 (RIC) to $637,193 at 1 year (not stratified). There is heterogeneity in the reporting of HRU and costs associated with allo-HSCT in the literature, making it difficult for clinicians, policymakers, and governments to draw definitive conclusions regarding the resources required for the delivery of these services. Nevertheless, to ensure that access to healthcare meets the necessary high cost and resource demands of allo-HSCT, it is imperative for clinicians, policymakers, and government officials to be aware of both the short- and long-term health resource requirements for this patient population. Further research is needed to understand the key determinants of HRU and costs associated with allo-HSCT to better inform the design and delivery of health care for HSCT recipients and ensure the quality, safety, and efficiency of care., (Copyright © 2024 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)
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- 2024
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13. Discrete Event Simulation to Incorporate Infusion Wait-Time When Assessing Cost-Effectiveness of a Chimeric-Antigen Receptor T Cell Therapy.
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Gye A, Lourenco RA, and Goodall S
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- Humans, Cost-Benefit Analysis, Waiting Lists, Immunotherapy, Adoptive, Cell- and Tissue-Based Therapy, Quality-Adjusted Life Years, Receptors, Chimeric Antigen
- Abstract
Objectives: The main objective was to use discrete event simulation to model the impact of wait-time, defined as the time between leukapheresis and chimeric antigen receptor (CAR-T) infusion, when assessing the cost-effectiveness of tisagenlecleucel in young patients with relapsed/refractory acute lymphoblastic leukemia., Methods: The movement of patients through the model was determined by parametric time-to-event distributions, with the competing risk of an event determining the costs and quality-adjusted life-years (QALYs) assigned. Cost-effectiveness was expressed using the incremental cost-effectiveness ratio (ICER) for tisagenlecleucel compared with chemotherapy over the lifetime., Results: The base case generated a total of 5.79 QALYs and $622 872 for tisagenlecleucel and 1.19 QALYs and $181 219 for blinatumomab, resulting in an ICER of $96 074 per QALY. An increase in mean CAR-T wait-time to 6.20 months reduced the benefit and costs of tisagenlecleucel to 2.78 QALYs and $294 478 because of fewer patients proceeding to infusion, reducing the ICER to $71 112 per QALY. Alternatively, when the cost of tisagenlecleucel was assigned pre-infusion in sensitivity analysis, the ICER increased with increasing wait-time., Conclusions: Under a payment arrangement where CAR-T cost is incurred post-infusion, the loss of benefit to patients is not reflected in the ICER. This may be misguiding to decision makers, where cost-effectiveness ratios are used to guide resource allocation. discrete event simulation is an important tool for economic modeling of CAR-T as it is amenable to capturing the impact of wait-time, facilitating better understanding of factors affecting service delivery and consequently informed decision making to deliver faster access to CAR-T for patients., Competing Interests: Author Disclosures Links to the disclosure forms provided by the authors are available here. The views expressed are those of the authors and not necessarily those of Novartis Pharmaceuticals or the Centre for Health Economics Research and Evaluation., (Copyright © 2024. Published by Elsevier Inc.)
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- 2024
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14. The Dedicated Imaging Post-Prostatectomy for Enhanced Radiotherapy outcomes (DIPPER) trial protocol: a multicentre, randomised trial of salvage radiotherapy versus surveillance for low-risk biochemical recurrence after radical prostatectomy.
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Roberts MJ, Conduit C, Davis ID, Effeney RM, Williams S, Martin JM, Hofman MS, Hruby G, Eapen R, Gianacas C, Papa N, Lourenço RA, Dhillon HM, Allen R, Fontela A, Kaur B, and Emmett L
- Subjects
- Male, Humans, Prostate pathology, Positron Emission Tomography Computed Tomography methods, Androgen Antagonists therapeutic use, Neoplasm Recurrence, Local pathology, Australia epidemiology, Prostatectomy methods, Salvage Therapy methods, Gallium Radioisotopes therapeutic use, Randomized Controlled Trials as Topic, Multicenter Studies as Topic, Clinical Trials, Phase II as Topic, Prostate-Specific Antigen, Prostatic Neoplasms diagnostic imaging, Prostatic Neoplasms radiotherapy, Prostatic Neoplasms surgery
- Abstract
Background: Salvage radiation therapy (SRT) and surveillance for low-risk prostate-specific antigen (PSA) recurrence have competing risks and benefits. The efficacy of early SRT to the prostate bed with or without pelvic lymph nodes compared to surveillance in patients with PSA recurrence after radical prostatectomy and no identifiable recurrent disease evident on prostate specific membrane antigen-positron emission tomography/computer tomography (PSMA-PET/CT) is unknown., Study Design: The Dedicated Imaging Post-Prostatectomy for Enhanced Radiotherapy outcomes (DIPPER) is an open-label, multicentre, randomised Phase II trial., Endpoints: The primary endpoint is 3-year event-free survival, with events comprising one of PSA recurrence (PSA ≥0.2 ng/mL higher than baseline), radiological evidence of metastatic disease, or initiation of systemic or other salvage treatments. Secondary endpoints include patient-reported outcomes, treatment patterns, participant perceptions, and cost-effectiveness., Eligibility Criteria: Eligible participants have PSA recurrence of prostate cancer after radical prostatectomy, defined by serum PSA level of 0.2-0.5 ng/mL, deemed low risk according to modified European Association of Urology biochemical recurrence risk criteria (International Society for Urological Pathology Grade Group ≤2, PSA doubling time >12 months), with no definite/probable recurrent prostate cancer on PSMA-PET/CT., Patients and Methods: A total of 100 participants will be recruited from five Australian centres and randomised 1:1 to SRT or surveillance. Participants will undergo 6-monthly clinical evaluation for up to 36 months. Androgen-deprivation therapy is not permissible. Enrolment commenced May 2023., Trial Registration: This trial has been registered with the Australian New Zealand Clinical Trials Registry (ACTRN: ACTRN12622001478707)., (© 2023 The Authors. BJU International published by John Wiley & Sons Ltd on behalf of BJU International.)
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- 2024
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15. An ex vitro hairy root system from petioles of detached soybean leaves for in planta screening of target genes and CRISPR strategies associated with nematode bioassays.
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Freitas-Alves NS, Moreira-Pinto CE, Arraes FBM, Costa LSL, de Abreu RA, Moreira VJV, Lourenço-Tessutti IT, Pinheiro DH, Lisei-de-Sa ME, Paes-de-Melo B, Pereira BM, Guimaraes PM, Brasileiro ACM, de Almeida-Engler J, Soccol CR, Morgante CV, Basso MF, and Grossi-de-Sa MF
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- Animals, RNA, Guide, CRISPR-Cas Systems, Biological Assay, Cotyledon, Glycine max genetics, Nematoda genetics
- Abstract
Main Conclusion: The ex vitro hairy root system from petioles of detached soybean leaves allows the functional validation of genes using classical transgenesis and CRISPR strategies (e.g., sgRNA validation, gene activation) associated with nematode bioassays. Agrobacterium rhizogenes-mediated root transformation has been widely used in soybean for the functional validation of target genes in classical transgenesis and single-guide RNA (sgRNA) in CRISPR-based technologies. Initial data showed that in vitro hairy root induction from soybean cotyledons and hypocotyls were not the most suitable strategies for simultaneous performing genetic studies and nematode bioassays. Therefore, an ex vitro hairy root system was developed for in planta screening of target molecules during soybean parasitism by root-knot nematodes (RKNs). Applying this method, hairy roots were successfully induced by A. rhizogenes from petioles of detached soybean leaves. The soybean GmPR10 and GmGST genes were then constitutively overexpressed in both soybean hairy roots and tobacco plants, showing a reduction in the number of Meloidogyne incognita-induced galls of up to 41% and 39%, respectively. In addition, this system was evaluated for upregulation of the endogenous GmExpA and GmExpLB genes by CRISPR/dCas9, showing high levels of gene activation and reductions in gall number of up to 58.7% and 67.4%, respectively. Furthermore, morphological and histological analyses of the galls were successfully performed. These collective data validate the ex vitro hairy root system for screening target genes, using classical overexpression and CRISPR approaches, directly in soybean in a simple manner and associated with nematode bioassays. This system can also be used in other root pathosystems for analyses of gene function and studies of parasite interactions with plants, as well as for other purposes such as studies of root biology and promoter characterization., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2023
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16. An analysis of the resource use and costs of febrile neutropenia events in pediatric cancer patients in Australia.
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Vargas C, Haeusler GM, Slavin MA, Babl FE, Mechinaud F, Phillips R, Thursky K, and Lourenco RA
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- Aged, Child, Humans, Australia, National Health Programs, Neoplasms complications, Neoplasms drug therapy, Antineoplastic Agents therapeutic use, Febrile Neutropenia drug therapy
- Abstract
Background: Febrile neutropenia (FN) in children with cancer generally requires in-hospital care, but low-risk patients may be successfully managed in an outpatient setting, potentially reducing the overall healthcare costs. Updated data on the costs of FN care are lacking., Methods: A bottom-up microcosting analysis was conducted from the healthcare system perspective using data collected alongside the Australian PICNICC (Predicting Infectious Complications of Neutropenic sepsis In Children with Cancer) study. Inpatient costs were accessed from hospital administrative records and outpatient costs from Medicare data. Costs were stratified by risk status (low/high risk) according to the PICNICC criteria. Estimated mean costs were obtained through bootstrapping and using a linear model to account for multiple events across individuals and other clinical factors that may impact costs., Results: The total costs of FN care were significantly higher for FN events classified as high-risk ($17,827, 95% confidence interval [CI]: $17,193-$18,461) compared to low-risk ($10,574, 95% CI: $9818-$11,330). In-hospital costs were significantly higher for high-risk compared to low-risk events, despite no differences in the cost structure, mean cost per day, and pattern of resource use. Hospital length of stay (LOS) was the only modifiable factor significantly associated with total costs of care. Excluding antineoplastics, antimicrobials are the most commonly used medications in the inpatient and outpatient setting for the overall period of analysis., Conclusion: The FN costs are driven by in-hospital admission and LOS. This suggests that the outpatient management of low-risk patients is likely to reduce the in-hospital cost of treating an FN event. Further research will determine if shifting the cost to the outpatient setting remains cost-effective overall., (© 2023 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC.)
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- 2023
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17. Education messages and strategies to inform the public, potential screening candidates and healthcare providers about lung cancer screening: A systematic review.
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Dodd RH, Sharman AR, McGregor D, Stone E, Donnelly C, Lourenco RA, Marshall H, and Rankin NM
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- Humans, United States, Early Detection of Cancer methods, Health Personnel education, Lung Neoplasms diagnosis, Lung Neoplasms prevention & control
- Abstract
International lung cancer screening (LCS) trials, using low-dose computed tomography, have demonstrated clinical effectiveness in reducing mortality from lung cancer. This systematic review aims to synthesise the key messages and strategies that could be successful in increasing awareness and knowledge of LCS, and ultimately increase uptake of screening. Studies were identified via relevant database searches up to January 2022. Two authors evaluated eligible studies, extracted and crosschecked data, and assessed quality. Results were synthesised narratively. Of 3205 titles identified, 116 full text articles were reviewed and 22 studies met the inclusion criteria. Twenty studies were conducted in the United States. While the study findings were heterogenous, key messages mentioned across multiple studies were about: provision of information on LCS and the recommendations for LCS (n = 8); benefits and harms of LCS (n = 6); cost of LCS and insurance coverage for participants (n = 6) and eligibility criteria (n = 5). To increase knowledge and awareness, evidence from awareness campaigns suggests that presenting information about eligibility and the benefits and harms of screening, may increase screening intention and uptake. Evidence from behavioural studies suggests that campaigns supporting engagement with platforms such as educational videos and digital awareness campaigns might be most effective. Group based learning appears to be most suited to increasing health professionals' knowledge. This systematic review found a lack of consistent evidence to demonstrate which strategies are most effective for increasing participant healthcare professional and community awareness and education about LCS., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: HM is an investigator on the ILST and ALST. ES is an investigator on the ILST., (Copyright © 2023. Published by Elsevier Inc.)
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- 2023
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18. Phase 1 study of safety, pharmacokinetics, and antiviral activity of SARS-CoV-2 neutralizing monoclonal antibody ABBV-47D11 in patients with COVID-19.
- Author
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Shebley M, Wang S, Ali I, Krishnan P, Tripathi R, Reardon JM, Cafardi J, Rahav G, Caraco Y, Slim J, Al Akhrass F, Yu M, Hu Y, Ferreira RA, and Alami NN
- Subjects
- Adult, Humans, SARS-CoV-2, Antibodies, Monoclonal pharmacokinetics, Antiviral Agents, Antibodies, Neutralizing, COVID-19
- Abstract
ABBV-47D11 is a neutralizing monoclonal antibody that targets a mutationally conserved hydrophobic pocket distal to the ACE2 binding site of SARS-CoV-2. This first-in-human safety, pharmacokinetics, and antiviral pharmacodynamic assessment in patients with COVID-19 provide an initial evaluation of this antibody that may allow further development. This multicenter, randomized, double-blind, and placebo-controlled single ascending dose study of ABBV-47D11 (180, 600, or 2400 mg) as an intravenous infusion, was in hospitalized and non-hospitalized (confined) adults with mild to moderate COVID-19. Primary outcomes were grade 3 or higher study drug-related adverse events and infusion-related reactions. Secondary outcomes were pharmacokinetic parameters and concentration-time profiles to Day 29, immunogenicity (anti-drug antibodies), and antiviral activity (change in RT-PCR viral load) from baseline to Days 15 and 29. ABBV-47D11 single doses up to 2400 mg were safe and tolerated and no safety signals were identified. The pharmacokinetics of ABBV-47D11 were linear and showed dose-proportional increases in serum concentrations with ascending doses. The exploratory anti-SARS-CoV-2 activity revealed a reduction of viral load at and above the 600 mg dose of ABBV-47D11 regardless of patient demographics and baseline characteristics, however; because of the high inter-individual variability and small sample size a statistical significance was not reached. There is potential for anti-SARS-CoV-2 activity with ABBV-47D11 doses of 600 mg or higher, which could be evaluated in future clinical trials designed and powered to assess viral load reductions and clinical benefit., (© 2022 AbbVie Inc and The Authors. Pharmacology Research & Perspectives published by British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics and John Wiley & Sons Ltd.)
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- 2023
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19. Cost-Effectiveness of Single Versus Multifraction SABR for Pulmonary Oligometastases: The SAFRON II Trial.
- Author
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Lourenco RA, Khoo T, Crothers A, Haas M, Montgomery R, Ball D, Bressel M, and Siva S
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- Humans, Australia, Cost-Benefit Analysis, Quality-Adjusted Life Years, Quality of Life, Radiosurgery
- Abstract
Purpose: The use of stereotactic ablative body radiation therapy (SABR) in advanced cancer care is increasing, yet the cost-effectiveness of single-fraction (SF) versus multifraction (MF) SABR in pulmonary oligometastases is unknown., Methods: A prespecified cost-effectiveness analysis was conducted of the Trans Tasman Radiation Oncology Group 13.01 - SAFRON II - randomized trial comparing SF with MF SABR in 87 patients with 133 pulmonary oligometastases. A partitioned survival model assessed costs and quality-adjusted life-years (QALY) over the within-trial period (4 years) and longer-term (10 years). Costs reflected a societal perspective, expressed in Australian dollars (A$) using 2020 prices and were estimated using patient level data on health care utilization for radiation therapy (including patient time), post-radiation systemic therapy and treatment of adverse effects. Quality of life was assessed using the EuroQoL EQ-5D-5L. The incremental cost-effectiveness ratio (ICER) was expressed as the cost per QALY gained for SF versus MF SABR, with uncertainty assessed using deterministic and probabilistic sensitivity analyses., Results: SF cost less than MF for initial therapy (difference of A$1194/patient). Mean time to initiation of systemic drug therapy did not differ between arms (P = .94). Numerical differences in survival favoring SF resulted in greater overall health care use for the within-trial period. The within-trial ICER was A$15,821/QALY and A$23,265/QALY over the longer term. Results were most sensitive to the cost of postprogression therapies and utility values. The sensitivity analysis indicated that SF SABR has a 97% probability of being cost-effective at a willingness-to-pay of A$50,000/QALY., Conclusions: SF has lower initial costs and is highly likely to be cost-effective. Time to initiation of systemic therapy associated with disease progression is highly patient relevant and is a major driver of cost-effectiveness. Comparisons for SF SABR with nonradiation therapy approaches to the treatment of pulmonary oligometastases warrant further investigation., (Copyright © 2022 Elsevier Inc. All rights reserved.)
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- 2022
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20. The SCRIPT trial: study protocol for a randomised controlled trial of a polygenic risk score to tailor colorectal cancer screening in primary care.
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Saya S, Boyd L, Chondros P, McNamara M, King M, Milton S, Lourenco RA, Clark M, Fishman G, Marker J, Ostroff C, Allman R, Walter FM, Buchanan D, Winship I, McIntosh J, Macrae F, Jenkins M, and Emery J
- Subjects
- Aged, Australia, Humans, Mass Screening methods, Middle Aged, Primary Health Care, Randomized Controlled Trials as Topic, Risk Assessment, Risk Factors, Colorectal Neoplasms diagnosis, Colorectal Neoplasms genetics, Early Detection of Cancer methods
- Abstract
Background: Polygenic risk scores (PRSs) can predict the risk of colorectal cancer (CRC) and target screening more precisely than current guidelines using age and family history alone. Primary care, as a far-reaching point of healthcare and routine provider of cancer screening and risk information, may be an ideal location for their widespread implementation., Methods: This trial aims to determine whether the SCRIPT intervention results in more risk-appropriate CRC screening after 12 months in individuals attending general practice, compared with standard cancer risk reduction information. The SCRIPT intervention consists of a CRC PRS, tailored risk-specific screening recommendations and a risk report for participants and their GP, delivered in general practice. Patients aged between 45 and 70 inclusive, attending their GP, will be approached for participation. For those over 50, only those overdue for CRC screening will be eligible to participate. Two hundred and seventy-four participants will be randomised to the intervention or control arms, stratified by general practice, using a computer-generated allocation sequence. The primary outcome is risk-appropriate CRC screening after 12 months. For those in the intervention arm, risk-appropriate screening is defined using PRS-derived risk; for those in the control arm, it is defined using family history and national screening guidelines. Timing, type and results of the previous screening are considered in both arms. Objective health service data will capture screening behaviour. Secondary outcomes include cancer-specific worry, risk perception, predictors of CRC screening behaviour, screening intentions and health service use at 1, 6 and 12 months post-intervention delivery., Discussion: This trial aims to determine whether a PRS-derived personalised CRC risk estimate delivered in primary care increases risk-appropriate CRC screening. A future population risk-stratified CRC screening programme could incorporate risk assessment within primary care while encouraging adherence to targeted screening recommendations., Trial Registration: Australian and New Zealand Clinical Trial Registry ACTRN12621000092897p. Registered on 1 February 2021., (© 2022. The Author(s).)
- Published
- 2022
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21. Prospective longitudinal evaluation of treatment-related toxicity and health-related quality of life during the first year of treatment for pediatric acute lymphoblastic leukemia.
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Schilstra CE, McCleary K, Fardell JE, Donoghoe MW, McCormack E, Kotecha RS, Lourenco RA, Ramachandran S, Cockcroft R, Conyers R, Cross S, Dalla-Pozza L, Downie P, Revesz T, Osborn M, Alvaro F, Wakefield CE, Marshall GM, Mateos MK, and Trahair TN
- Subjects
- Acute Disease, Child, Humans, Male, Quality of Life, Retrospective Studies, Surveys and Questionnaires, Pancreatitis, Precursor Cell Lymphoblastic Leukemia-Lymphoma drug therapy
- Abstract
Background: Pediatric acute lymphoblastic leukemia (ALL) therapy is accompanied by treatment-related toxicities (TRTs) and impaired quality of life. In Australia and New Zealand, children with ALL are treated with either Children's Oncology Group (COG) or international Berlin-Frankfurt-Munster (iBFM) Study Group-based therapy. We conducted a prospective registry study to document symptomatic TRTs (venous thrombosis, neurotoxicity, pancreatitis and bone toxicity), compare TRT outcomes to retrospective TRT data, and measure the impact of TRTs on children's general and cancer-related health-related quality of life (HRQoL) and parents' emotional well-being., Methods: Parents of children with newly diagnosed ALL were invited to participate in the ASSET (Acute Lymphoblastic Leukaemia Subtypes and Side Effects from Treatment) study and a prospective, longitudinal HRQoL study. TRTs were reported prospectively and families completed questionnaires for general (Healthy Utility Index Mark 3) and cancer specific (Pediatric Quality of Life Inventory (PedsQL)-Cancer Module) health related quality of life as well the Emotion Thermometer to assess emotional well-being., Results: Beginning in 2016, 260 pediatric patients with ALL were enrolled on the TRT registry with a median age at diagnosis of 59 months (range 1-213 months), 144 males (55.4%), majority with Pre-B cell immunophenotype, n = 226 (86.9%), 173 patients (66.5%) treated according to COG platform with relatively equal distribution across risk classification sub-groups. From 2018, 79 families participated in the HRQoL study through the first year of treatment. There were 74 TRT recorded, reflecting a 28.5% risk of developing a TRT. Individual TRT incidence was consistent with previous studies, being 7.7% for symptomatic VTE, 11.9% neurotoxicity, 5.4% bone toxicity and 5.0% pancreatitis. Children's HRQoL was significantly lower than population norms throughout the first year of treatment. An improvement in general HRQoL, measured by the HUI3, contrasted with the lack of improvement in cancer-related HRQoL measured by the PedsQL Cancer Module over the first 12 months. There were no persisting differences in the HRQoL impact of COG compared to iBFM therapy., Conclusions: It is feasible to prospectively monitor TRT incidence and longitudinal HRQoL impacts during ALL therapy. Early phases of ALL therapy, regardless of treatment platform, result in prolonged reductions in cancer-related HRQoL., (© 2022. The Author(s).)
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- 2022
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22. Preferences for HIV Testing Services and HIV Self-Testing Distribution Among Migrant Gay, Bisexual, and Other Men Who Have Sex With Men in Australia.
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Zhang Y, Wiseman V, Applegate TL, Lourenco RA, Street DJ, Smith K, Jamil MS, Terris-Prestholt F, Fairley CK, McNulty A, Hynes A, Johnson K, Chow EPF, Bavinton BR, Grulich A, Stoove M, Holt M, Kaldor J, Guy R, and Ong JJ
- Abstract
Background: In Australia, undiagnosed HIV rates are much higher among migrant gay, bisexual, or other men who have sex with men (GBMSM) than Australian-born GBMSM. HIV self-testing is a promising tool to overcome barriers to HIV testing and improve HIV testing uptake among migrant GBMSM. We compared the preferences for HIV testing services, including HIV self-testing, among migrant and Australian-born GBMSM., Methods: Preferences were assessed via two discrete choice experiments (DCEs). Participants were recruited between December 2017 and January 2018 using online and offline advertising and randomly assigned to complete one of two online DCE surveys. Migrant GBMSM were classified as being born in a country with a reciprocal healthcare agreement (RHCA) with Australia (providing free or subsided health care) or not. Latent class analysis and mixed logit models were used to explore heterogeneity in preferences., Findings: We recruited 1,606 GBMSM, including 583 migrant men of whom 419 (72%) were born in non-RHCA countries. Most participants preferred a free or cheap oral test with higher accuracy and a shorter window period to facilitate early detection of infections. Cost was more important for men born in non-RHCA countries than for men from RHCA countries or Australia. All groups preferred accessing kits through online distributers or off the shelf purchasing from pharmacies. Men born in RHCA countries least preferred accessing HIV self-testing kits from a medical clinic, while more than half of men from non-RHCA countries most preferred sourcing kits from a clinic. Sex-on-premises venues were the least preferred location to access test kits among all groups. In addition, two latent class analyses explored heterogeneity in preferences among men from non-RHCA countries and we found four latent classes for HIV testing services and two latent classes for HIVST distribution., Interpretation: Our findings emphasise the need for high-performing and low-cost HIV self-testing kits that are accessible from a variety of distribution points as a component of Australia's HIV response, especially for those who do not have access to free or subsidised health care in Australia., Competing Interests: AH was employed by Thorne Harbour Health. KJ was employed by ACON. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhang, Wiseman, Applegate, Lourenco, Street, Smith, Jamil, Terris-Prestholt, Fairley, McNulty, Hynes, Johnson, Chow, Bavinton, Grulich, Stoove, Holt, Kaldor, Guy and Ong.)
- Published
- 2022
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23. GUIDE: a randomised non-comparative phase II trial of biomarker-driven intermittent docetaxel versus standard-of-care docetaxel in metastatic castration-resistant prostate cancer (clinical trial protocol).
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Conduit C, Mak B, Qu W, Lulio JD, Burder R, Bressel M, Cusick T, Dhillon HM, Lourenço RA, Underhill C, Torres J, Crumbaker M, Honeyball F, Linton A, Allen R, Davis ID, Clark SJ, Horvath LG, and Mahon KL
- Abstract
Objective: To determine the efficacy and safety of intermittent docetaxel chemotherapy guided by circulating methylated glutathione S-transferase Pi-1 ( mGSTP1 ) in men with metastatic castration-resistant prostate cancer (CRPC)., Patients and Methods: GUIDE (NCT04918810) is a randomised, two-arm, non-comparative phase-2 trial recruiting 120 patients at six Australian centres. Patients with Prostate Cancer Working Group-3 defined metastatic CRPC who are commencing docetaxel 75 mg/m
2 q3w will be pre-screened for detectable mGSTP1 at baseline ± following two cycles of treatment. Those with detectable plasma mGSTP1 at baseline that becomes undetectable after two cycles of chemotherapy will be eligible for GUIDE. Prior to Cycle 4 of docetaxel, these patients are randomised 2:1 to one of two treatment arms: Arm A (cease docetaxel and reinstitute if mGSTP1 becomes detectable) or Arm B (continue docetaxel 75 mg/m2 q3w in accordance with clinician's usual practice). The primary endpoint is radiographic progression-free survival. Secondary endpoints include time on treatment holidays, safety, patient-reported outcomes, overall survival, health resource use, and cost associated with treatment. Enrolment commenced November 2021., Results and Conclusion: The results of this trial will generate data on the clinical utility of mGSTP1 as a novel biomarker to guide treatment de-escalation in metastatic CRPC., Competing Interests: Conflict of interest statement: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s), 2022.)- Published
- 2022
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24. LUMOS - Low and Intermediate Grade Glioma Umbrella Study of Molecular Guided TherapieS at relapse: Protocol for a pilot study.
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Kong BY, Sim HW, Nowak AK, Yip S, Barnes EH, Day BW, Buckland ME, Verhaak R, Johns T, Robinson C, Thomas MA, Giardina T, Lwin Z, Scott AM, Parkinson J, Jeffree R, Lourenco RA, Hovey EJ, Cher LM, Kichendasse G, Khasraw M, Hall M, Tu E, Amanuel B, Koh ES, and Gan HK
- Subjects
- Adult, Humans, Australia, Multicenter Studies as Topic, Pilot Projects, Recurrence, Review Literature as Topic, Antineoplastic Agents therapeutic use, Brain Neoplasms genetics, Brain Neoplasms therapy, Brain Neoplasms diagnosis, Glioblastoma drug therapy, Glioblastoma genetics, Glioma drug therapy, Glioma genetics
- Abstract
Introduction: Grades 2 and 3 gliomas (G2/3 gliomas), when combined, are the second largest group of malignant brain tumours in adults. The outcomes for G2/3 gliomas at progression approach the dismal outcomes for glioblastoma (GBM), yet there is a paucity of trials for Australian patients with relapsed G2/3 gliomas compared with patients with GBM. LUMOS will be a pilot umbrella study for patients with relapsed G2/3 gliomas that aims to match patients to targeted therapies based on molecular screening with contemporaneous tumour tissue. Participants in whom no actionable or no druggable mutation is found, or in whom the matching drug is not available, will form a comparator arm and receive standard of care chemotherapy. The objective of the LUMOS trial is to assess the feasibility of this approach in a multicentre study across five sites in Australia, with a view to establishing a national molecular screening platform for patient treatment guided by the mutational analysis of contemporaneous tissue biopsies METHODS AND ANALYSIS: This study will be a multicentre pilot study enrolling patients with recurrent grade 2/3 gliomas that have previously been treated with radiotherapy and chemotherapy at diagnosis or at first relapse. Contemporaneous tumour tissue at the time of first relapse, defined as tissue obtained within 6 months of relapse and without subsequent intervening therapy, will be obtained from patients. Molecular screening will be performed by targeted next-generation sequencing at the reference laboratory (PathWest, Perth, Australia). RNA and DNA will be extracted from representative formalin-fixed paraffin embedded tissue scrolls or microdissected from sections on glass slides tissue sections following a review of the histology by pathologists. Extracted nucleic acid will be quantified by Qubit Fluorometric Quantitation (Thermo Fisher Scientific). Library preparation and targeted capture will be performed using the TruSight Tumor 170 (TST170) kit and samples sequenced on NextSeq 550 (Illumina) using NextSeq V.2.5 hi output reagents, according to the manufacturer's instructions. Data analysis will be performed using the Illumina BaseSpace TST170 app v1.02 and a custom tertiary pipeline, implemented within the Clinical Genomics Workspace software platform from PierianDx (also refer to section 3.2). Primary outcomes for the study will be the number of patients enrolled and the number of patients who complete molecular screening. Secondary outcomes will include the proportion of screened patients enrolled; proportion of patients who complete molecular screening; the turn-around time of molecular screening; and the value of a brain tumour specific multi-disciplinary tumour board, called the molecular tumour advisory panel as measured by the proportion of patients in whom the treatment recommendation was refined compared with the recommendations from the automated bioinformatics platform of the reference laboratory testing., Ethics and Dissemination: The study was approved by the lead Human Research Ethics Committee of the Sydney Local Health District: Protocol No. X19-0383. The study will be conducted in accordance with the principles of the Declaration of Helsinki 2013, guidelines for Good Clinical Practice and the National Health and Medical Research Council National Statement on Ethical Conduct in Human Research (2007, updated 2018 and as amended periodically). Results will be disseminated using a range of media channels including newsletters, social media, scientific conferences and peer-reviewed publications., Trial Registration Number: ACTRN12620000087954; Pre-results., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2021
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25. Home-based care of low-risk febrile neutropenia in children-an implementation study in a tertiary paediatric hospital.
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Haeusler GM, Gaynor L, Teh B, Babl FE, Orme LM, Segal A, Mechinaud F, Bryant PA, Phillips B, Lourenco RA, Slavin MA, and Thursky KA
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- Adolescent, Child, Child, Preschool, Female, Hospitals, Pediatric, Humans, Male, Prospective Studies, Tertiary Care Centers, Febrile Neutropenia therapy, Home Care Services standards, Quality of Life psychology
- Abstract
Background: Home-based management of low-risk febrile neutropenia (FN) is safe, improves quality of life and reduces healthcare expenditure. A formal low-risk paediatric program has not been implemented in Australia. We aimed to describe the implementation process and evaluate the clinical impact., Method: This prospective study incorporated three phases: implementation, intervention and evaluation. A low-risk FN implementation toolkit was developed, including a care-pathway, patient information, home-based assessment and educational resources. The program had executive-level endorsement, a multidisciplinary committee and a nurse specialist. Children with cancer and low-risk FN were eligible to be transferred home with a nurse visiting daily after an overnight period of observation for intravenous antibiotics. Low-risk patients were identified using a validated decision rule, and suitability for home-based care was determined using disease, chemotherapy and patient-level criteria. Plan-Do-Study-Act methodology was used to evaluate clinical impact and safety., Results: Over 18 months, 292 children with FN were screened: 132 (45%) were low-risk and 63 (22%) were transferred to home-based care. Compared with pre-implementation there was a significant reduction in in-hospital median LOS (4.0 to 1.5 days, p < 0.001) and 291 in-hospital bed days were saved. Eight (13%) patients needed readmission and there were no adverse outcomes. A key barrier was timely screening of all patients and program improvements, including utilising the electronic medical record for patient identification, are planned., Conclusion: This program significantly reduces in-hospital LOS for children with low-risk FN. Ongoing evaluation will inform sustainability, identify areas for improvement and support national scale-up of the program.
- Published
- 2021
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26. Event-Free Survival, a Prostate-Specific Antigen-Based Composite End Point, Is Not a Surrogate for Overall Survival in Men With Localized Prostate Cancer Treated With Radiation.
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Xie W, Regan MM, Buyse M, Halabi S, Kantoff PW, Sartor O, Soule H, Berry D, Clarke N, Collette L, D'Amico A, Lourenco RA, Dignam J, Eisenberger M, James N, Fizazi K, Gillessen S, Loriot Y, Mottet N, Parulekar W, Sandler H, Spratt DE, Sydes MR, Tombal B, Williams S, and Sweeney CJ
- Subjects
- Aged, Disease Progression, Humans, Male, Middle Aged, Neoplasm Metastasis, Neoplasm Recurrence, Local, Predictive Value of Tests, Progression-Free Survival, Prostatic Neoplasms blood, Prostatic Neoplasms mortality, Prostatic Neoplasms pathology, Randomized Controlled Trials as Topic, Risk Assessment, Risk Factors, Time Factors, Endpoint Determination, Kallikreins blood, Prostate-Specific Antigen blood, Prostatic Neoplasms radiotherapy
- Abstract
Purpose: Recently, we have shown that metastasis-free survival is a strong surrogate for overall survival (OS) in men with intermediate- and high-risk localized prostate cancer and can accelerate the evaluation of new (neo)adjuvant therapies. Event-free survival (EFS), an earlier prostate-specific antigen (PSA)-based composite end point, may further expedite trial completion., Methods: EFS was defined as the time from random assignment to the date of first evidence of disease recurrence, including biochemical failure, local or regional recurrence, distant metastasis, or death from any cause, or was censored at the date of last PSA assessment. Individual patient data from trials within the Intermediate Clinical Endpoints in Cancer of the Prostate-ICECaP-database with evaluable PSA and disease follow-up data were analyzed. We evaluated the surrogacy of EFS for OS using a 2-stage meta-analytic validation model by determining the correlation of EFS with OS (patient level) and the correlation of treatment effects (hazard ratios [HRs]) on both EFS and OS (trial level). A clinically relevant surrogacy was defined a priori as an R
2 ≥ 0.7., Results: Data for 10,350 patients were analyzed from 15 radiation therapy-based trials enrolled from 1987 to 2011 with a median follow-up of 10 years. At the patient level, the correlation of EFS with OS was 0.43 (95% CI, 0.42 to 0.44) as measured by Kendall's tau from a copula model. At the trial level, the R2 was 0.35 (95% CI, 0.01 to 0.60) from the weighted linear regression of log(HR)-OS on log(HR)-EFS., Conclusion: EFS is a weak surrogate for OS and is not suitable for use as an intermediate clinical end point to substitute for OS to accelerate phase III (neo)adjuvant trials of prostate cancer therapies for primary radiation therapy-based trials.- Published
- 2020
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27. A prospective randomized multicentre study of the impact of gallium-68 prostate-specific membrane antigen (PSMA) PET/CT imaging for staging high-risk prostate cancer prior to curative-intent surgery or radiotherapy (proPSMA study): clinical trial protocol.
- Author
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Hofman MS, Murphy DG, Williams SG, Nzenza T, Herschtal A, Lourenco RA, Bailey DL, Budd R, Hicks RJ, Francis RJ, and Lawrentschuk N
- Subjects
- Antigens, Surface analysis, Contrast Media chemistry, Glutamate Carboxypeptidase II analysis, Humans, Male, Neoplasm Staging, Prospective Studies, Prostate diagnostic imaging, Prostatic Neoplasms therapy, Radiopharmaceuticals chemistry, Antigens, Surface metabolism, Contrast Media therapeutic use, Gallium Radioisotopes therapeutic use, Glutamate Carboxypeptidase II metabolism, Positron Emission Tomography Computed Tomography methods, Prostatic Neoplasms diagnostic imaging, Radiopharmaceuticals therapeutic use
- Abstract
Background: Accurate staging of patients with prostate cancer (PCa) is important for therapeutic decision-making. Relapse after surgery or radiotherapy of curative intent is not uncommon and, in part, represents a failure of staging with current diagnostic imaging techniques to detect disease spread. Prostate-specific membrane antigen (PSMA) positron-emission tomography (PET)/computed tomography (CT) is a new whole-body scanning technique that enables visualization of PCa with high contrast. The hypotheses of this study are that: (i) PSMA-PET/CT has improved diagnostic performance compared with conventional imaging; (ii) PSMA-PET/CT should be used as a first-line diagnostic test for staging; (iii) the improved diagnostic performance of PSMA-PET/CT will result in significant management impact; and (iv) there are economic benefits if PSMA-PET/CT is incorporated into the management algorithm., Objectives and Methods: The proPSMA trial is a prospective, multicentre study in which patients with untreated high-risk PCa will be randomized to gallium-68-PSMA-11 PET/CT or conventional imaging, consisting of CT of the abdomen/pelvis and bone scintigraphy with single-photon emission CT/CT. Patients eligible for inclusion are those with newly diagnosed PCa with select high-risk features, defined as International Society of Urological Pathology grade group ≥3 (primary Gleason grade 4, or any Gleason grade 5), prostate-specific antigen level ≥20 ng/mL or clinical stage ≥T3. Patients with negative, equivocal or oligometastatic disease on first line-imaging will cross over to receive the other imaging arm. The primary objective is to compare the accuracy of PSMA-PET/CT with that of conventional imaging for detecting nodal or distant metastatic disease. Histopathological, imaging and clinical follow-up at 6 months will define the primary endpoint according to a predefined scoring system. Secondary objectives include comparing management impact, the number of equivocal studies, the incremental value of second-line imaging in patients who cross over, the cost of each imaging strategy, radiation exposure, inter-observer agreement and safety of PSMA-PET/CT. Longer-term follow-up will also assess the prognostic value of a negative PSMA-PET/CT., Outcome and Significance: This trial will provide data to establish whether PSMA-PET/CT should replace conventional imaging in the primary staging of select high-risk localized PCa, or whether it should be used to provide incremental diagnostic information in selected cases., (© 2018 The Authors BJU International © 2018 BJU International Published by John Wiley & Sons Ltd.)
- Published
- 2018
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28. Interplay between Mutations and Efflux in Drug Resistant Clinical Isolates of Mycobacterium tuberculosis .
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Machado D, Coelho TS, Perdigão J, Pereira C, Couto I, Portugal I, Maschmann RA, Ramos DF, von Groll A, Rossetti MLR, Silva PA, and Viveiros M
- Abstract
Numerous studies show efflux as a universal bacterial mechanism contributing to antibiotic resistance and also that the activity of the antibiotics subject to efflux can be enhanced by the combined use of efflux inhibitors. Nevertheless, the contribution of efflux to the overall drug resistance levels of clinical isolates of Mycobacterium tuberculosis is poorly understood and still is ignored by many. Here, we evaluated the contribution of drug efflux plus target-gene mutations to the drug resistance levels in clinical isolates of M. tuberculosis . A panel of 17 M. tuberculosis clinical strains were characterized for drug resistance associated mutations and antibiotic profiles in the presence and absence of efflux inhibitors. The correlation between the effect of the efflux inhibitors and the resistance levels was assessed by quantitative drug susceptibility testing. The bacterial growth/survival vs. growth inhibition was analyzed through the comparison between the time of growth in the presence and absence of an inhibitor. For the same mutation conferring antibiotic resistance, different MICs were observed and the different resistance levels found could be reduced by efflux inhibitors. Although susceptibility was not restored, the results demonstrate the existence of a broad-spectrum synergistic interaction between antibiotics and efflux inhibitors. The existence of efflux activity was confirmed by real-time fluorometry. Moreover, the efflux pump genes mmr, mmpL7, Rv1258c, p55 , and efpA were shown to be overexpressed in the presence of antibiotics, demonstrating the contribution of these efflux pumps to the overall resistance phenotype of the M. tuberculosis clinical isolates studied, independently of the genotype of the strains. These results showed that the drug resistance levels of multi- and extensively-drug resistant M. tuberculosis clinical strains are a combination between drug efflux and the presence of target-gene mutations, a reality that is often disregarded by the tuberculosis specialists in favor of the almost undisputed importance of antibiotic target-gene mutations for the resistance in M. tuberculosis .
- Published
- 2017
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29. Cardiofaciocutaneous syndrome and the dermatologist's contribution to diagnosis.
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Rocha VB, Moraes RA, and Pereira LB
- Subjects
- Child, Preschool, Ectodermal Dysplasia genetics, Ectodermal Dysplasia physiopathology, Facies, Failure to Thrive genetics, Failure to Thrive physiopathology, Female, Heart Defects, Congenital genetics, Heart Defects, Congenital physiopathology, Humans, Professional Role, Dermatologists, Ectodermal Dysplasia diagnosis, Failure to Thrive diagnosis, Heart Defects, Congenital diagnosis
- Published
- 2017
30. Masticatory efficiency and bite force in individuals with normal occlusion.
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de Abreu RA, Pereira MD, Furtado F, Prado GP, Mestriner W Jr, and Ferreira LM
- Subjects
- Adolescent, Adult, Brazil, Female, Humans, Male, Bite Force, Dental Occlusion, Mastication physiology, Masticatory Muscles physiology
- Abstract
Objective: The aim of the study was to evaluate and correlate masticatory efficiency (ME) and maximum bite force (MBF) in adult individuals of both genders with normal occlusion., Design: The study was conducted in a university research centre. ME and MBF were evaluated in 55 adults (27 men and 28 women) with normal occlusion. All subjects chewed four fuchsin capsules (two on the right and two on the left molar region) for 15 chewing cycles with a 3-min interval between capsules. The concentration of fuchsin in the capsules was determined by spectrophotometry and stratified by gender and chewing side. Bite force (BF) was measured three times on both the left and right molars; the highest value of the three measurements on each side was taken as the MBF., Results: ME was higher in women (right side, 1.17±016μg/mL; left side, 1.20±0.15μg/mL) than in men (right side, 0.92±0.24μg/mL; left side, 0.89±0.24μg/mL). The MBF was higher in men (right side, 632±174N; left side, 627±170N) compared with women (right side, 427±140N; left side, 420±112N). No significant differences in chewing efficiency and BF were found between sides for both genders., Conclusions: Women showed the highest ME, while men had the highest MBF, with no correlation between these two parameters among genders., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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31. Strategies for surgically assisted rapid maxillary expansion according to the region of transverse maxillary deficiency.
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Pereira MD, de Abreu RA, Prado GP, and Ferreira LM
- Subjects
- Adult, Cephalometry instrumentation, Female, Humans, Male, Maxilla abnormalities, Maxilla diagnostic imaging, Tomography, X-Ray Computed, Treatment Outcome, Young Adult, Maxilla surgery, Orthognathic Surgical Procedures methods, Palatal Expansion Technique
- Abstract
This study evaluated different techniques for surgically assisted rapid maxillary expansion (SARME) according to the type of transverse maxillary deficiency using computed tomography (CT). Six adult patients with bilateral transverse maxillary deficiencies underwent SARME. The patients were equally divided into three groups: Group I, maxillary atresia in both the anterior and posterior regions; Group II, greater maxillary atresia in the anterior region; and Group III, increased maxillary atresia in the posterior region. In Group I, a subtotal Le Fort I osteotomy was used. In Group II, a subtotal Le Fort I osteotomy was used without pterygomaxillary suture disjunction. In Group III, a subtotal Le Fort I osteotomy was used with pterygomaxillary suture disjunction and fixation of the anterior nasal spine with steel wire. The midpalatal suture opening was evaluated preoperatively and immediately after the activation period using CT. For Group I, the opening occurred parallel to midpalatal suture; for Group II, the opening comprised a V-shape with a vertex on the posterior nasal spine; and for Group III, the opening comprised a V-shape with a vertex at the anterior nasal spine. The conclusion was that the SARME technique should be individualized according to the type of transverse maxillary deficiency., (Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2012
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32. Laparoscopic ureteral reimplant for ureteral stricture.
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Soares RS, de Abreu RA Jr, and Tavora JE
- Subjects
- Adolescent, Adult, Aged, Female, Follow-Up Studies, Humans, Male, Middle Aged, Treatment Outcome, Ureteral Obstruction etiology, Urologic Surgical Procedures methods, Laparoscopy methods, Replantation methods, Ureter surgery, Ureteral Obstruction surgery
- Abstract
Purpose: Evaluate the initial experience of laparoscopic ureteral reimplant for ureteral stenosis., Materials and Methods: From January 2004 to June 2008, 10 patients underwent 11 laparoscopic reconstruction surgeries for ureteral stenosis. Seven cases of stenosis of the distal ureter, two at the level of iliac vessels, a case of bilateral distal stenosis and one in the medium third. Eight ureteroneocystotomies were performed by extravesical technique with anti-reflux mechanism, two cases of vesical reimplant with Boari technique and one case using the psoas hitch technique., Results: The average surgical time was 166 minutes (115-245 min), mean blood loss was 162 mL (100-210 mL) and the average hospital stay was 2.9 days (2-4 days). There were two complications: a lesion of the sigmoid colon identified peroperatively and treated with laparoscopic sutures with good evolution, and a case of ureteral stone obstruction at the 30th day postoperative, treated by laser ureterolitotripsy. All patients had resolution of the stenosis at an average follow-up period of 18 months (3-54 months)., Conclusion: Laparoscopic surgery represents a feasible, safe and low morbidity technique for ureteral reimplant in ureteral stenosis.
- Published
- 2010
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33. Differential amperometric determination of hydrogen peroxide in honeys using flow-injection analysis with enzymatic reactor.
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Franchini RA, Matos MA, Colombara R, and Matos RC
- Subjects
- Electric Conductivity, Enzymes, Immobilized, Peroxidase metabolism, Electrochemistry instrumentation, Electrochemistry methods, Flow Injection Analysis methods, Honey analysis, Hydrogen Peroxide chemistry
- Abstract
Hydrogen peroxide (H2O2) present in honey was rapidly determined by the differential amperometric method in association with flow-injection analysis (FIA) and a tubular reactor containing immobilized enzymes. A gold electrode modified by electrochemical deposition of platinum was employed as working electrode. Hydrogen peroxide was quantified in 14 samples of Brazilian commercial honeys using amperometric differential measurements at +0.60V vs. Ag/AgCl((sat)). For the enzymatic consumption of H2O2, a tubular reactor containing immobilized peroxidase was constructed using an immobilization of enzymes on Amberlite IRA-743 resin. The linear dynamic range in H2O2 extends from 1 to 100 x 10(-6) mol L(-1), at pH 7.0. At flow rate of 2.0 mL min(-1) and injecting 150 microL sample volumes, the sampling frequency of the 90 determinations per hour is afforded. This method is based on three steps involving the flow-injection of: (1) the sample spiked with a standard solution, (2) the pure sample and (3) the enzymatically treated sample with peroxidase immobilized. The reproducibility of the current peaks for hydrogen peroxide in 10(-5) mol L(-1) range concentration showed a relative standard deviation (R.S.D.) better than 1%. The detection limit of this method is 2.9 x 10(-7) mol L(-1). The honey samples analyses were compared with the parallel spectrophotometric determination, and showed an excellent correlation between the methods.
- Published
- 2008
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34. Rapid determination of hydrogen peroxide using peroxidase immobilized on Amberlite IRA-743 and minerals in honey.
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Franchini RA, de Souza CF, Colombara R, Matos MA, and Matos RC
- Subjects
- Resins, Synthetic, Enzymes, Immobilized, Honey analysis, Hydrogen Peroxide analysis, Peroxidase, Trace Elements analysis
- Abstract
Hydrogen peroxide and trace metals (K+, Ca2+, Na+, Mg2+, Mn2+, and Li+) were determined in 14 samples of Brazilian commercial honeys. The method for the determination of H2O2 is based on selective oxidation of H2O2 using an on-line tubular reactor containing peroxidase immobilized on Amberlite IRA-743 resin. Reactors presented high stability for at least 2 weeks under intense use. The results show a simple, accurate, selective, and readily applied method to the determination of H2O2 in honey. The trace metals were determined by capillary zone electrophoresis. Mean contents of 656, 69.1, 71.8, 36.0, 21.4, and 1.70 mg/kg were found, respectively, for K+, Ca2+, Na+, Mg2+, Mn2+, and Li+ in the analyzed honeys. The cations were identified by comparison of the relative migration times of their peaks with the Ba2+ migration time used as reference. The electrophoretic analysis was simple and rapid and did not require any other preparation of sample than dilution and filtration.
- Published
- 2007
- Full Text
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35. Polyamines and DNA methylation in childhood leukaemia.
- Author
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Schipper RG, van den Heuvel LP, Verhofstad AA, and De Abreu RA
- Subjects
- Child, DNA, Neoplasm genetics, DNA, Neoplasm metabolism, Humans, S-Adenosylmethionine metabolism, DNA Methylation, Polyamines metabolism, Precursor Cell Lymphoblastic Leukemia-Lymphoma genetics, Precursor Cell Lymphoblastic Leukemia-Lymphoma metabolism
- Abstract
Both polyamine metabolism and DNA methylation play an important role in normal and malignant growth. Specific enzyme inhibitors or drugs that interfere with these metabolic pathways have proven to be potential anticancer agents. Since DNA methylation and polyamine metabolism depend on a common substrate, i.e. S-adenosylmethionine, interaction between both pathways can be expected. Little is known about the relationship between these pathways but studies are available indicating that polyamines and DNA methylation are directly or indirectly interconnected, metabolically as well as physiologically with respect to the regulation of cell growth, differentiation and cancer development. These considerations give rise to the possibility that, by targeting both pathways, a more profound and effective inhibitory effect on the growth of malignant cells can be achieved. In previous studies we showed that 6-MP (6-mercaptopurine) as well as MTX (methotrexate), well-known drugs in the treatment of acute lymphoblastic leukaemia, inhibit DNA methylation and induce apoptosis in malignant blood cells. Our recent results show that combined treatment with 6-MP, MTX and drugs interfering with polyamine metabolism has additive/synergistic effects on the growth, cell viability and/or apoptotic death of leukaemic cells. Such a combination therapy could have great clinical value for patients in which therapy using inhibitors of thiopurines/purine metabolism has failed.
- Published
- 2007
- Full Text
- View/download PDF
36. Monitoring of inosine monophosphate dehydrogenase activity in mononuclear cells of children with acute lymphoblastic leukemia: enzymological and clinical aspects.
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Brouwer C, Vermunt-de Koning DG, Trueworthy RC, Ter Riet PG, Duley JA, Trijbels FJ, Hoogerbrugge PM, Bökkerink JP, van Wering ER, and De Abreu RA
- Subjects
- Adolescent, Adult, Child, Child, Preschool, Enzyme Activation, Female, Humans, IMP Dehydrogenase chemistry, Infant, Male, Precursor Cell Lymphoblastic Leukemia-Lymphoma diagnosis, Precursor Cell Lymphoblastic Leukemia-Lymphoma therapy, IMP Dehydrogenase metabolism, Leukocytes, Mononuclear enzymology, Precursor Cell Lymphoblastic Leukemia-Lymphoma enzymology
- Abstract
Background: Inosine 5'-monophosphate dehydrogenase (IMPDH; EC1.1.1.205) catalyzes the rate-limiting step in guanine nucleotide biosynthesis, and may play an important role in treatment of patients with antipurines., Methods: We used an HPLC method to measure the IMPDH activity in peripheral blood and bone marrow mononuclear cells (MNC). IMPDH activities were determined in children who were diagnosed with and treated for acute lymphoblastic leukemia (ALL), and in a group of control children., Results: The median IMPDH activity for control children was 350 pmol/10(6) pMNC/hr (range 97-896; n = 47). No gender or age differences were observed. IMPDH activity at diagnosis of ALL was correlated with the percentage of peripheral blood lymphoblasts (r = 0.474; P < 0.001; n = 71). The median IMPDH activity at diagnosis was 410 pmol/10(6) pMNC/hr (range 40-2009; n = 76), significantly higher than for controls (P = 0.012). IMPDH activity significantly decreased after induction treatment, and during treatment with methotrexate (MTX) infusions (median 174 pmol/10(6) pMNC/hr; range 52-516; n = 21). The activity remained low during maintenance treatment with 6-mercaptopurine (6MP) and MTX, at a significantly lower level than for controls (P < 0.004). One year after cessation of treatment IMPDH activity returned to normal values., Conclusion: The decrease of IMPDH activity at remission of ALL seems to be at least partly due to the eradication of lymphoblasts with the type 2 isoform of the enzyme.
- Published
- 2006
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- View/download PDF
37. Role of 5'-nucleotidase in thiopurine metabolism: enzyme kinetic profile and association with thio-GMP levels in patients with acute lymphoblastic leukemia during 6-mercaptopurine treatment.
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Brouwer C, Vogels-Mentink TM, Keizer-Garritsen JJ, Trijbels FJ, Bökkerink JP, Hoogerbrugge PM, van Wering ER, Veerman AJ, and De Abreu RA
- Subjects
- Child, Chromatography, High Pressure Liquid, Humans, Hydrogen-Ion Concentration, Kinetics, Mercaptopurine pharmacology, Substrate Specificity, 5'-Nucleotidase metabolism, Guanosine Monophosphate blood, Mercaptopurine therapeutic use, Precursor Cell Lymphoblastic Leukemia-Lymphoma drug therapy, Precursor Cell Lymphoblastic Leukemia-Lymphoma metabolism, Sulfhydryl Compounds chemistry, Thioguanine metabolism
- Abstract
Thiopurines are used for treatment of several diseases. Cytotoxicity is caused by the derived compounds 6-thioguanine nucleotides (TGNs) and methyl-6-thioinosine monophosphate (methylthio-IMP). The 6-thiopurine mononucleotides 6-thio-IMP (thio-IMP), 6-thio-GMP (thio-GMP) and methylthio-IMP can be catabolized by purine 5'-nucleotidase. It has been shown that the various 5'-nucleotidases are key enzymes for (6-thio)-purine metabolism. We aimed to investigate whether the overall 5'-nucleotidase (5'NT) activity is correlated with the efficacy and toxicity of 6-thiopurine nucleotides. Substrate affinity of 5'NT for IMP, GMP, AMP, thio-IMP, thio-GMP and methylthio-IMP was studied in human lymphocytes. For each of the substrates, the pH for optimal overall enzyme activity has been determined at a pH range between 6 and 10. At the optimal pH, assays were performed to establish Km and Vmax values. Optimal pH values for the various substrates were between 7 and 8.5. Km values ranged from 33 to 109 microM, Vmax ranged from 3.99 to 19.5 nmol/10(6) peripheral mononuclear cells (pMNC) h, and Vmax/Km ratios ranged from 105 to 250. The results did not show a distinct preference of 5'NT activity for any of the tested thiopurine nucleotides. The enzyme kinetic studies furthermore revealed substrate inhibition by thio-IMP and thio-GMP as a substrate. Inhibition by thio-GMP also seems to occur in patients treated with 6-mercaptopurine (6 MP); subsequently, this may lead to toxicity in these patients.
- Published
- 2005
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38. Thiopurine methyltransferase in acute lymphoblastic leukaemia: biochemical and molecular biological aspects.
- Author
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Brouwer C, De Abreu RA, Keizer-Garritsen JJ, Lambooy LH, Ament K, ter Riet PG, van Wering ER, Trijbels FJ, Veerman AJ, Hoogerbrugge PM, and Bökkerink JP
- Subjects
- Child, Child, Preschool, Female, Folic Acid Antagonists therapeutic use, Genotype, Humans, Male, Methotrexate therapeutic use, Methyltransferases genetics, Mutation genetics, Precursor Cell Lymphoblastic Leukemia-Lymphoma drug therapy, Precursor Cell Lymphoblastic Leukemia-Lymphoma genetics, Trimethoprim therapeutic use, Methyltransferases metabolism, Precursor Cell Lymphoblastic Leukemia-Lymphoma enzymology
- Abstract
Thiopurine S-methyltransferase (TPMT) is a cytosolic enzyme, catalysing S-methylation of aromatic and heterocyclic sulphhydryl compounds. TPMT activities and genotypes have been determined in patients with acute lymphoblastic leukaemia (ALL) and in control children. Median red blood cell (RBC) TPMT activity in ALL patients at diagnosis was significantly lower than in controls (median 11.5 pmol/10(7) RBC*hr; range 1.7-30.7; n = 191 vs. 14.6 pmol/10(7) RBC*hr; range 1.6-50.7; n = 140). This reduction of TPMT activity in ALL patients was not due to differences in the frequency of mutations in the TPMT gene. In concordance with other authors, we found a higher TPMT activity during maintenance treatment with 6-mercaptopurine (6MP) than at diagnosis and in controls. However, we observed that TPMT activity was already significantly increased after the induction therapy, before the patients received 6MP (median 17.5; range 3.9-40.3 pmol/10(7) RBC*hr; n = 139). In vitro experiments indicate that the early increase of TPMT activity during treatment may be explained by the use of antifolates, e.g., methotrexate and trimethoprim.
- Published
- 2005
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39. Bcl-2 prevents loss of mitochondria in CCCP-induced apoptosis.
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de Graaf AO, van den Heuvel LP, Dijkman HB, de Abreu RA, Birkenkamp KU, de Witte T, van der Reijden BA, Smeitink JA, and Jansen JH
- Subjects
- Adenosine Triphosphate metabolism, Animals, Caspases metabolism, Cell Nucleus, Enzyme Activation drug effects, Humans, Jurkat Cells, Lymphoma, B-Cell metabolism, Lymphoma, B-Cell pathology, Membrane Potentials drug effects, Mice, Mitochondria drug effects, Proto-Oncogene Proteins c-bcl-2 genetics, Proto-Oncogene Proteins c-bcl-2 pharmacology, Apoptosis drug effects, Carbonyl Cyanide m-Chlorophenyl Hydrazone pharmacology, Mitochondria metabolism, Proto-Oncogene Proteins c-bcl-2 metabolism
- Abstract
Bcl-2 family proteins regulate apoptosis at the level of mitochondria. To examine the mechanism of Bcl-2 function, we investigated the effects of the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on two hematopoietic cell lines and Bcl-2 overexpressing transfectants. CCCP directly interferes with mitochondrial function and induces apoptosis. We show that Bcl-2 inhibits apoptosis and that the antiapoptotic effect of Bcl-2 takes place upstream of caspase activation and nuclear changes associated with apoptosis, since these were markedly inhibited in cells overexpressing Bcl-2. Bcl-2 does not prevent the decrease in mitochondrial membrane potential nor the alterations in cellular ATP content induced by CCCP in FL5.12 and Jurkat cells. A higher number of mitochondria was observed in untreated Bcl-2 transfected cells compared to parental cells, as shown by electron microscopy. Exposure to CCCP induced a dramatic decrease in the number of mitochondria and severely disrupted mitochondrial ultrastructure, with apparent swelling and loss of cristae in parental cells. Bcl-2 clearly diminished the disruption of mitochondrial structure and preserved a higher number of mitochondria. These data suggest that CCCP induces apoptosis by structural disruption of mitochondria and that Bcl-2 prevents apoptosis and mitochondrial degeneration by preserving mitochondrial integrity.
- Published
- 2004
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40. Purine and pyrimidine metabolism: new challenges.
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Peters GJ, van Kuilenburg AB, and de Abreu RA
- Subjects
- Cell Line, Tumor, Gene Expression Regulation, Humans, Hypoxanthine Phosphoribosyltransferase genetics, International Cooperation, DNA chemistry, Genetic Techniques, Purine Nucleotides chemistry, Pyrimidine Nucleotides chemistry
- Published
- 2004
- Full Text
- View/download PDF
41. Genetic polymorphism of thiopurine S-methyltransferase in Argentina.
- Author
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Laróvere LE, de Kremer RD, Lambooy LH, and De Abreu RA
- Subjects
- Adolescent, Adult, Aged, Alleles, Argentina, Child, Child, Preschool, Ethnicity genetics, Female, Humans, Infant, Infant, Newborn, Male, Methyltransferases metabolism, Middle Aged, Methyltransferases genetics, Polymorphism, Genetic
- Abstract
Background: Thiopurine methyltransferase (TPMT) catalyses the S-methylation of 6-thiopurine drugs, which are commonly used in the treatment of autoimmune diseases, leukaemia and organ transplantation. TPMT activity is polymorphic as a result of gene mutations. Ethnic variations in phenotype and genotype have been identified in previous population studies, but no information was available within Latin-American populations., Aim: To establish the genetic polymorphism of TPMT in an Argentine population., Methods: TPMT enzymatic activity of 147 healthy Argentine subjects was measured using a high-performance liquid chromatography method. The genotyping assay for nine defective alleles (TPMT*2 - *8) was based on restriction fragment length polymorphism polymerase chain reaction and allele-specific polymerase chain reaction methods., Results: All subjects had detectable TPMT activity. Twelve individuals with low to intermediate activity were heterozygous for one of the mutant alleles: nine were TPMT*1/*3A, two TPMT*1/*2 and one TPMT*1/*4. All examined subjects with normal activity had wild-type genotype (TPMT*1/*1)., Conclusion: Variant TPMT alleles were present in 8.2% of the examined subjects, which is in accordance with other studies. The frequency of TPMT*3A, TPMT*2 and TPMT*4 was 3.1%, 0.7% and 0.3%, respectively. TPMT*3A was the most prevalent allele, which is in accordance with results from Caucasian populations. This study provides the first analysis of TPMT activity and allele frequency distribution in Argentina, South America.
- Published
- 2003
- Full Text
- View/download PDF
42. Real-time analysis of tyrosine hydroxylase gene expression: a sensitive and semiquantitative marker for minimal residual disease detection of neuroblastoma.
- Author
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Lambooy LH, Gidding CE, van den Heuvel LP, Hulsbergen-van de Kaa CA, Ligtenberg M, Bökkerink JP, and De Abreu RA
- Subjects
- Base Sequence, Biomarkers, Tumor, Brain Neoplasms genetics, DNA Primers, Gene Expression Regulation, Enzymologic, Genes, myc, Humans, Immunohistochemistry, Neoplasm, Residual genetics, Neuroblastoma genetics, Polymerase Chain Reaction methods, Predictive Value of Tests, Prognosis, RNA, Messenger genetics, Reproducibility of Results, Reverse Transcriptase Polymerase Chain Reaction, Sensitivity and Specificity, Tumor Cells, Cultured, Brain Neoplasms diagnosis, Gene Expression Regulation, Neoplastic, Neoplasm, Residual diagnosis, Neuroblastoma diagnosis, Tyrosine 3-Monooxygenase genetics
- Abstract
Purpose: The purpose of this study was to establish a sensitive and semiquantitative method for the detection of minimal residual disease of neuroblastoma, the most common solid tumor in childhood., Experimental Design: Analysis was performed on a molecular level by reverse transcription-PCR using a new, real-time detection method. We measured two genes simultaneously, tyrosine hydroxylase (TH) as the target gene and glyceraldehyde-3-phosphate dehydrogenase as a reference gene, in blood and bone marrow samples at diagnosis and after follow-up from six patients with neuroblastoma, one patient with ganglioneuroma, and one patient with ganglioneuroblastoma., Results: The sensitivity of the assay was 1:10(6) peripheral WBCs. Four patients with stage IV neuroblastoma and one patient with stage III neuroblastoma were scored positive. The other stage III patient and the other two patients with ganglioneuroma and ganglioneuroblastoma followed by acute lymphoblastic leukemia, respectively, were scored negative. Control bone marrow aspirates were also negative. The TH assay is more sensitive than immunohistochemical detection, and the results of the TH assay corresponded with the results of MYCN amplification., Conclusions: The described TH assay is specific, sensitive, and semiquantitative and can be used for the detection of neuroblastoma cell involvement in bone marrow and blood at diagnosis and during therapy. Furthermore, the TH assay is a possible prognostic marker for neuroblastoma.
- Published
- 2003
43. Measurement of thiopurine S-methyltransferase activity in human blood samples based on high-performance liquid chromatography: reference values in erythrocytes from children.
- Author
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Keizer-Garritsen JJ, Brouwer C, Lambooy LH, Ter Riet P, Bökkerink JP, Trijbels FJ, and De Abreu RA
- Subjects
- Bone Marrow drug effects, Child, Chromatography, High Pressure Liquid methods, Erythrocytes metabolism, Humans, Kinetics, Leukocytes, Mononuclear metabolism, Mercaptopurine blood, Reference Values, Reproducibility of Results, Time Factors, Erythrocytes enzymology, Mercaptopurine analogs & derivatives, Methyltransferases blood
- Abstract
Background: Monitoring 6-thiopurine S-methyltransferase (TPMT; EC 2.1.1.67) activity is especially important when patients are treated with 6-thiopurine drugs, since severe bone marrow toxicity may be induced if patients have deficient TPMT activity., Methods: We have developed a method based on high-performance liquid chromatography (HPLC) for the measurement of TPMT activity in various cell types: erythrocytes (RBC), human peripheral blood mononuclear cells (pMNC) and human malignant lymphoblasts (Molt-F4). The enzymatic activity is measured by the amount of 6-methylmercaptopurine formed, using 6-mercaptopurine (6MP) as substrate and S-adenosylmethionine as co-substrate., Results: The K(m) values calculated for 6MP were 0.54 (RBC), 0.85 (pMNC) and 0.65 (Molt-F4 cells) mmol/L. The K(m) values for S-adenosylmethionine were 11.9 (RBC), 16.4 (pMNC) and 6.65 (Molt-F4 cells) micro mol/L. The assay variation was 8.2-17%. TPMT activity was determined in a control group of 103 children and young adults (44 female, 59 male). The values observed were (mean +/- standard deviation): female children and young adults, 15.1 +/- 4.8 pmol/10(7) cells per h (n = 44); male children and young adults, 15.8 +/- 6.4 pmol/10(7) cells per h (n = 59). No gender or age differences were found., Conclusion: The HPLC-based method enables the rapid screening of TPMT activities in large groups of patients treated with 6-thiopurines.
- Published
- 2003
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- View/download PDF
44. Combination therapy in childhood leukaemia: in vitro studies of thiopurines and inhibitors of purine metabolism on apoptosis.
- Author
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De Abreu RA, Trueworthy RC, van Kuilenburg AB, Vogels-Mentink TM, Lambooy LH, and van Gennip AH
- Subjects
- Annexin A5 pharmacology, Cell Survival, Child, Coloring Agents pharmacology, Humans, Methotrexate therapeutic use, Models, Biological, Ribavirin analogs & derivatives, Ribavirin therapeutic use, Thioguanine therapeutic use, Time Factors, Tumor Cells, Cultured, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Apoptosis, Leukemia therapy, Mercaptopurine therapeutic use, Purines metabolism
- Abstract
Background: Methotrexate (MTX) followed by 6-mercaptopurine (6MP) is one of the best known combinations for the treatment of childhood acute lymphoblastic leukaemia. Tiazofurin (TF) and 6-thioguanine (TG) are also used as chemotherapy agents in the treatment of malignancies. We have examined the induction of apoptosis by combinations of these drugs to gain more insights into their efficacy in the treatment of malignancies., Methods: The induction of apoptosis was examined in Molt-4, a human malignant acute lymphoblastic T-cell line. The cells were exposed to increasing drug concentrations at various exposure times. Annexin V/FITC and propidium iodide (PI) were used as markers for apoptosis and cell death. Annexin V/FITC positive and PI positive cells were detected by flow-cytometric analysis., Results: Sequential 24-h exposure with MTX (0.005-0.02 micro mol) followed by 6MP (1-10 micro mol) and 24-h exposure with TF (5-20 micro mol) followed by TG (0.5-2 micro mol) showed a more than additive induction of apoptosis compared with single-drug exposure. Simultaneous administration of the drugs does not show an additive effect on apoptosis., Conclusions: The results of this study indicate that sequential administration of MTX before 6MP and of TF before TG may be essential for therapeutic success in the treatment of leukaemia.
- Published
- 2003
- Full Text
- View/download PDF
45. Pharmacogenetic and clinical aspects of dihydropyrimidine dehydrogenase deficiency.
- Author
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van Kuilenburg AB, De Abreu RA, and van Gennip AH
- Subjects
- Alleles, Codon, Nonsense, Dihydrouracil Dehydrogenase (NADP), Fluorouracil pharmacology, Genotype, Humans, Leukocytes, Mononuclear metabolism, Models, Biological, Models, Genetic, Mutation, Mutation, Missense, Polymorphism, Genetic, Oxidoreductases deficiency
- Abstract
Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of 5-fluorouracil (5FU). A deficiency of DPD is increasingly being recognized as the cause of an important pharmacogenetic syndrome. The importance of DPD deficiency in the aetiology of unexpected severe 5FU toxicity has been demonstrated by the fact that, in 39-59% of cases, decreased DPD activity could be detected in peripheral blood mononuclear (PBM) cells. It was observed that 55% of the patients with a decreased DPD activity suffered from grade IV neutropenia compared with 13% of the patients with a normal DPD activity (P = 0.01). Furthermore, toxicity developed significantly earlier in patients with low DPD activity than in patients with normal DPD activity (10.0 +/- 7.6 versus 19.1 +/- 15.3 days, P < 0.05). In patients suffering from severe 5FU-associated toxicity, 11 mutations have been identified in DPYD, including one splice-site mutation (IVS14 + 1G-->A), one nonsense mutation (E386X), four missense mutations (M166V, V335L, I560S, D949V) and five polymorphisms (C29R, R21Q, S534N, I543V, V732I). Considering the common use of 5FU in the treatment of cancer patients, the severe 5FU-related toxicities in patients with a low DPD activity and the high prevalence of the IVS14 + 1G-->A mutation, analysis of the DPD activity in PBM cells or screening for the IVS14 + 1G-->A mutation should be routinely carried out prior to the start of treatment with 5FU.
- Published
- 2003
- Full Text
- View/download PDF
46. Moderate citrullinaemia without hyperammonaemia in a child with mutated and deficient argininosuccinate synthetase.
- Author
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Ruitenbeek W, Kobayashi K, Iijima M, Smeitink JA, Engelke UF, De Abreu RA, Kwast HT, Saheki T, Boelen CA, De Jong JG, and Wevers RA
- Subjects
- Amino Acids blood, Animals, Child, Preschool, DNA Mutational Analysis, Female, Fibroblasts metabolism, Humans, Hyperammonemia diagnosis, Mice, Mutation, Missense, Rats, Reverse Transcriptase Polymerase Chain Reaction, Skin metabolism, Argininosuccinate Synthase deficiency, Argininosuccinate Synthase genetics, Citrullinemia diagnosis
- Abstract
In a patient with microcephaly, feeding problems and restlessness, moderately increased serum and urine citrulline concentrations were observed. Protein and allopurinol loading did not result in additional indications for a urea cycle defect. The diagnosis of citrullinaemia was made at both the enzyme and DNA level, resulting from a novel mutation in the argininosuccinate synthetase gene. The fact that the patient has not suffered from severe deterioration, and that there were only minor abnormalities in metabolite concentrations, suggests that the argininosuccinate synthetase capacity was less affected in vivo than in vitro. In vitro nuclear magnetic resonance investigation suggested an active acetylation mechanism for citrulline. This case illustrates the importance of performing extensive biochemical and molecular investigations in order to reach a definitive diagnosis, particularly in instances of moderate citrullinaemia.
- Published
- 2003
- Full Text
- View/download PDF
47. Thiopurine metabolism and identification of the thiopurine metabolites transported by MRP4 and MRP5 overexpressed in human embryonic kidney cells.
- Author
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Wielinga PR, Reid G, Challa EE, van der Heijden I, van Deemter L, de Haas M, Mol C, Kuil AJ, Groeneveld E, Schuetz JD, Brouwer C, De Abreu RA, Wijnholds J, Beijnen JH, and Borst P
- Subjects
- Biological Transport, Cells, Cultured, Chromatography, High Pressure Liquid, Drug Interactions, Humans, Kidney cytology, Kidney embryology, Kinetics, Mercaptopurine pharmacology, Methylthioinosine pharmacology, Multidrug Resistance-Associated Proteins biosynthesis, Ribosomal Proteins biosynthesis, Thioguanine pharmacology, Transfection, Mercaptopurine metabolism, Multidrug Resistance-Associated Proteins metabolism, Ribosomal Proteins metabolism, Thioguanine metabolism
- Abstract
Mercaptopurines have been used as anticancer agents for more than 40 years, and most acute lymphoblastic leukemias are treated with 6-mercaptopurine (6MP) or 6-thioguanine (TG). Overexpression of the two related multidrug resistance proteins MRP4 and MRP5 has been shown to confer some resistance against mercaptopurines, which has been attributed to extrusion of mercaptopurine metabolites by these transporters. We have analyzed the mercaptopurine metabolites formed in human embryonic kidney cells and determined which metabolites are extruded by MRP4 and MRP5. Incubation with 6MP led to the formation of thioinosine and thioxanthosine metabolites and we found that thio-IMP was transported by both MRP4 and MRP5; MRP5 showed the highest transport rate. In contrast, only MRP5 transported thioxanthosine monophosphate (tXMP). During incubation with TG, the monophosphorylated form of thioguanosine was transported by both MRP4 and MRP5; the highest transport rate was for MRP4. Similarly, only 6-methyl-thio-IMP was formed during incubation with 6-methyl mercaptopurine riboside. This compound was a substrate for both MRP4 and MRP5; MRP4 showed the highest transport rate. Our results show that all major thiopurine monophosphates important in the efficacy of mercaptopurine treatment are transported by MRP4 and MRP5, although the substrate specificity of the two transporters differs in detail.
- Published
- 2002
- Full Text
- View/download PDF
48. Genetic basis of inosine triphosphate pyrophosphohydrolase deficiency.
- Author
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Sumi S, Marinaki AM, Arenas M, Fairbanks L, Shobowale-Bakre M, Rees DC, Thein SL, Ansari A, Sanderson J, De Abreu RA, Simmonds HA, and Duley JA
- Subjects
- Adult, Base Sequence, Child, DNA, Complementary, Female, Humans, Male, Molecular Sequence Data, Protein Structure, Secondary, Pyrophosphatases chemistry, Pyrophosphatases deficiency, Inosine Triphosphatase, Pyrophosphatases genetics
- Abstract
Inosine triphosphate pyrophosphohydrolase (ITPase) deficiency is a common inherited condition characterized by the abnormal accumulation of inosine triphosphate (ITP) in erythrocytes. The genetic basis and pathological consequences of ITPase deficiency are unknown. We have characterized the genomic structure of the ITPA gene, showing that it has eight exons. Five single nucleotide polymorphisms were identified, three silent (138G-->A, 561G-->A, 708G-->A) and two associated with ITPase deficiency (94C-->A, IVS2+21A-->C). Homozygotes for the 94C-->A missense mutation (Pro32 to Thr) had zero erythrocyte ITPase activity, whereas 94C-->A heterozygotes averaged 22.5% of the control mean, a level of activity consistent with impaired subunit association of a dimeric enzyme. ITPase activity of IVS2+21A-->C homozygotes averaged 60% of the control mean. In order to explore further the relationship between mutations and enzyme activity, we examined the association between genotype and ITPase activity in 100 healthy controls. Ten subjects were heterozygous for 94C-->A (allele frequency: 0.06), 24 were heterozygotes for IVS2+21A-->C (allele frequency: 0.13) and two were compound heterozygous for these mutations. The activities of IVS2+21A-->C heterozygotes and 94C-->A/IVS2+21A-->C compound heterozygotes were 60% and 10%, respectively, of the normal control mean, suggesting that the intron mutation affects enzyme activity. In all cases when ITPase activity was below the normal range, one or both mutations were found. The ITPA genotype did not correspond to any identifiable red cell phenotype. A possible relationship between ITPase deficiency and increased drug toxicity of purine analogue drugs is proposed.
- Published
- 2002
- Full Text
- View/download PDF
49. 1H-NMR spectroscopy of cerebrospinal fluid of fetal sheep during hypoxia-induced acidemia and recovery.
- Author
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Van Cappellen Van Walsum AM, Jongsma HW, Wevers RA, Nijhuis JG, Crevels J, Engelke UF, De Abreu RA, Moolenaar SH, Oeseburg B, and Nijland R
- Subjects
- 3-Hydroxybutyric Acid cerebrospinal fluid, Animals, Choline cerebrospinal fluid, Citric Acid cerebrospinal fluid, Creatinine cerebrospinal fluid, Energy Metabolism, Female, Glucose cerebrospinal fluid, Hypoxanthine cerebrospinal fluid, Inositol cerebrospinal fluid, Lactic Acid cerebrospinal fluid, Pregnancy, Protons, Pyruvic Acid cerebrospinal fluid, Sheep, Succinic Acid cerebrospinal fluid, Valine cerebrospinal fluid, Acidosis cerebrospinal fluid, Hypoxia cerebrospinal fluid, Magnetic Resonance Spectroscopy
- Abstract
The purpose of the study was to investigate the sequence of processes occurring during and after hypoxia-induced acidemia. We used proton nuclear magnetic resonance spectroscopy, which provides an overview of metabolites in cerebrospinal fluid (CSF), reflecting neuronal metabolism and damage. The pathophysiological condition of acute fetal asphyxia was mimicked by reducing maternal uterine blood flow in 14 unanesthetized pregnant ewes. CSF metabolites were measured during hypoxia-induced acidemia, and during the following recovery period, including the periods at 24 and 48 h after the hypoxic insult. Maximum values of the following CSF metabolites were reached during severe hypoxia (pH
- Published
- 2002
- Full Text
- View/download PDF
50. 2,8-Dihydroxyadenine urolithiasis in a patient with considerable residual adenine phosphoribosyltransferase activity in cell extracts but with mutations in both copies of APRT.
- Author
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Deng L, Yang M, Fründ S, Wessel T, De Abreu RA, Tischfield JA, and Sahota A
- Subjects
- Child, DNA Mutational Analysis, Exons genetics, Humans, Lymphocytes enzymology, Male, Adenine analogs & derivatives, Adenine metabolism, Adenine Phosphoribosyltransferase genetics, Adenine Phosphoribosyltransferase metabolism, Mutation, Urinary Calculi genetics, Urinary Calculi metabolism
- Abstract
We have examined the mutational basis of adenine phosphoribosyltransferase (APRT, EC 2.4.2.7) deficiency (MIM 102600) in a patient of Polish origin who has been passing 2,8-dihydroxyadenine (DHA) stones since birth, but has considerable residual enzyme activity in lymphocyte extracts. The five exons and flanking regions of APRT were amplified by PCR and then sequenced. A single T insertion was identified at the intron 4 splice donor site (TGgtaa to TGgttaa:IVS4+2insT) in one allele from the proband, his mother, and brother. A G-to-T transversion in exon 5 (GTC-to-TTC:c.448G>T, V150F) was identified in the other allele, and this mutation was also present in one allele from the father and the paternal grandmother. Tru91 and AvaII digestions of PCR products spanning exons 4 and 5, respectively, confirmed the mutations. The mother was heterozygous for an intragenic TaqI site, but all other family members were homozygous for the presence of this site. IVS4+2insT, located on the allele containing the TaqI site, has been identified previously in several families from Europe, suggesting a founder effect, but the substitution in exon 5 is a novel mutation. IVS4+2insT is known to result in complete loss of enzyme activity, and our results suggest that V150F produces an enzyme that is nonfunctional in vivo but has considerable residual activity in vitro., (Copyright 2001 Academic Press.)
- Published
- 2001
- Full Text
- View/download PDF
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