47 results on '"Groot, R."'
Search Results
2. Bacteremia in Childhood Life-Threatening Infections in Urban Gambia: EUCLIDS in West Africa
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MS Mondziekten/Kaakchirurgie, Infectieziekten patientenzorg, Secka, F, Herberg, J A, Sarr, I, Darboe, S, Sey, G, Saidykhan, M, Wathuo, M, Kaforou, M, Antonio, M, Roca, A, Zaman, S M A, Cebey-López, M, Boeddha, N P, Paulus, S, Kohlfürst, D S, Emonts, M, Zenz, W, Carrol, E D, de Groot, R, Schlapbach, L, Martinon-Torres, F, Bojang, K, Levin, M, van der Flier, M, Anderson, S T, MS Mondziekten/Kaakchirurgie, Infectieziekten patientenzorg, Secka, F, Herberg, J A, Sarr, I, Darboe, S, Sey, G, Saidykhan, M, Wathuo, M, Kaforou, M, Antonio, M, Roca, A, Zaman, S M A, Cebey-López, M, Boeddha, N P, Paulus, S, Kohlfürst, D S, Emonts, M, Zenz, W, Carrol, E D, de Groot, R, Schlapbach, L, Martinon-Torres, F, Bojang, K, Levin, M, van der Flier, M, and Anderson, S T
- Published
- 2019
3. Communal Creativity as Socio-musical Practice
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Lapidaki, E., de Groot, R., Stagkos, P., McPherson, G.E., Welch, G., and ASCA (FGw)
- Published
- 2012
4. Geospatial data infrastructure : concepts, cases and good practice
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Groot, R., McLaughlin, J., Faculty of Geo-Information Science and Earth Observation, and Department of Earth Observation Science
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EOS ,ADLIB-BOOK-279 - Published
- 2000
5. Raising AWaRe-ness of Antimicrobial Stewardship Challenges in Pediatric Emergency Care: Results from the PERFORM Study Assessing Consistency and Appropriateness of Antibiotic Prescribing Across Europe.
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Kolberg L, Khanijau A, van der Velden FJS, Herberg J, De T, Galassini R, Cunnington AJ, Wright VJ, Shah P, Kaforou M, Wilson C, Kuijpers T, Martinón-Torres F, Rivero-Calle I, Moll H, Vermont C, Pokorn M, Kolnik M, Pollard AJ, Agyeman PKA, Schlapbach LJ, Tsolia MN, Yeung S, Zavadska D, Zenz W, Schweintzger NA, van der Flier M, de Groot R, Usuf E, Voice M, Calvo-Bado L, Mallet F, Fidler K, Levin M, Carrol ED, Emonts M, and von Both U
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- Child, Humans, Drug Prescriptions, Europe, Emergency Service, Hospital, Fever diagnosis, Fever drug therapy, Penicillins therapeutic use, Anti-Bacterial Agents therapeutic use, Antimicrobial Stewardship methods
- Abstract
Background: Optimization of antimicrobial stewardship is key to tackling antimicrobial resistance, which is exacerbated by overprescription of antibiotics in pediatric emergency departments (EDs). We described patterns of empiric antibiotic use in European EDs and characterized appropriateness and consistency of prescribing., Methods: Between August 2016 and December 2019, febrile children attending EDs in 9 European countries with suspected infection were recruited into the PERFORM (Personalised Risk Assessment in Febrile Illness to Optimise Real-Life Management) study. Empiric systemic antibiotic use was determined in view of assigned final "bacterial" or "viral" phenotype. Antibiotics were classified according to the World Health Organization (WHO) AWaRe classification., Results: Of 2130 febrile episodes (excluding children with nonbacterial/nonviral phenotypes), 1549 (72.7%) were assigned a bacterial and 581 (27.3%) a viral phenotype. A total of 1318 of 1549 episodes (85.1%) with a bacterial and 269 of 581 (46.3%) with a viral phenotype received empiric systemic antibiotics (in the first 2 days of admission). Of those, the majority (87.8% in the bacterial and 87.0% in the viral group) received parenteral antibiotics. The top 3 antibiotics prescribed were third-generation cephalosporins, penicillins, and penicillin/β-lactamase inhibitor combinations. Of those treated with empiric systemic antibiotics in the viral group, 216 of 269 (80.3%) received ≥1 antibiotic in the "Watch" category., Conclusions: Differentiating bacterial from viral etiology in febrile illness on initial ED presentation remains challenging, resulting in a substantial overprescription of antibiotics. A significant proportion of patients with a viral phenotype received systemic antibiotics, predominantly classified as WHO Watch. Rapid and accurate point-of-care tests in the ED differentiating between bacterial and viral etiology could significantly improve antimicrobial stewardship., Competing Interests: Potential conflicts of interest. A. J. C. reports 2 grants from UK Research and Innovation (principal investigator), outside the submitted work, a grant from the National Institute of Health and Care Research (as joint lead of the Global Health Research Group), and a role as chair of the Committee for Scientific Affairs and Awards for European Society for Paediatric Infectious Disease. F. M-T. reports financial support for educational activities from Sanofi, MSD, Moderna, GlaxoSmithKline (GSK), Biofabri, AstraZeneca, Novavax, Janssen, and Pfizer, outside the submitted work; travel expenses and meeting fees covered by Pfizer, MSD, GSK, and Sanofi; participation on a data safety monitoring board or advisory board for Pfizer and Biofabri; ; roles as coordinator of Spanish Pediatric Critical Trials Network and coordinator of the World Health Organization (WHO) Collaborating Centre for Vaccine Safety of Santiago de Compostela; and roles as principal investigator in randomized controlled trials for Ablynx, Abbott, Seqirus, Sanofi, MSD, Merck, Pfizer, Roche, Regeneron, Jansen, Medimmune, Novavax, Novartis and GSK. A. J. P. reports consulting fees from Shionogi, outside the submitted work; grants or contracts paid to the institution from the Bill & Melinda Gates Foundation, the Wellcome Trust, Cepi, the Medical Research Council, and the National Institute for Health and Care Research; royalties or licenses from AstraZeneca (Oxford University has entered into a partnership with AstraZeneca for development of coronavirus disease 2019 [COVID-19] vaccines); and unpaid roles as chair of the Department of Health and Social Care's Joint Committee on Vaccination and Immunisation and as a member of the WHO Strategic Advisory Group of Experts on Immunization (SAGE) until 2022. P. K. A. A. was a member of the Sanofi advisory board for nirsevimab in 2022. M. N. T. reports consulting fees for an MSD advisory board, support for attending IDWeek 2022 from Pfizer and IDWeek 2023 from Janssen, and unpaid participation on the Scientific Advisory Group of Experts for COVID-19 (Greece) and the National Committee for immunization Practices (Greece). U. v. B. reports financial support for educational activities (lectures on antimicrobial stewardship; pediatric educational curricula) from MSD, outside the submitted work. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)
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- 2024
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6. Diagnosis of Multisystem Inflammatory Syndrome in Children by a Whole-Blood Transcriptional Signature.
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Jackson HR, Miglietta L, Habgood-Coote D, D'Souza G, Shah P, Nichols S, Vito O, Powell O, Davidson MS, Shimizu C, Agyeman PKA, Beudeker CR, Brengel-Pesce K, Carrol ED, Carter MJ, De T, Eleftheriou I, Emonts M, Epalza C, Georgiou P, De Groot R, Fidler K, Fink C, van Keulen D, Kuijpers T, Moll H, Papatheodorou I, Paulus S, Pokorn M, Pollard AJ, Rivero-Calle I, Rojo P, Secka F, Schlapbach LJ, Tremoulet AH, Tsolia M, Usuf E, Van Der Flier M, Von Both U, Vermont C, Yeung S, Zavadska D, Zenz W, Coin LJM, Cunnington A, Burns JC, Wright V, Martinon-Torres F, Herberg JA, Rodriguez-Manzano J, Kaforou M, and Levin M
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- Child, Humans, COVID-19 Testing, Hospitals, Systemic Inflammatory Response Syndrome diagnosis, Systemic Inflammatory Response Syndrome genetics, COVID-19 diagnosis, COVID-19 genetics, COVID-19 complications, Mucocutaneous Lymph Node Syndrome diagnosis, Mucocutaneous Lymph Node Syndrome genetics
- Abstract
Background: To identify a diagnostic blood transcriptomic signature that distinguishes multisystem inflammatory syndrome in children (MIS-C) from Kawasaki disease (KD), bacterial infections, and viral infections., Methods: Children presenting with MIS-C to participating hospitals in the United Kingdom and the European Union between April 2020 and April 2021 were prospectively recruited. Whole-blood RNA Sequencing was performed, contrasting the transcriptomes of children with MIS-C (n = 38) to those from children with KD (n = 136), definite bacterial (DB; n = 188) and viral infections (DV; n = 138). Genes significantly differentially expressed (SDE) between MIS-C and comparator groups were identified. Feature selection was used to identify genes that optimally distinguish MIS-C from other diseases, which were subsequently translated into RT-qPCR assays and evaluated in an independent validation set comprising MIS-C (n = 37), KD (n = 19), DB (n = 56), DV (n = 43), and COVID-19 (n = 39)., Results: In the discovery set, 5696 genes were SDE between MIS-C and combined comparator disease groups. Five genes were identified as potential MIS-C diagnostic biomarkers (HSPBAP1, VPS37C, TGFB1, MX2, and TRBV11-2), achieving an AUC of 96.8% (95% CI: 94.6%-98.9%) in the discovery set, and were translated into RT-qPCR assays. The RT-qPCR 5-gene signature achieved an AUC of 93.2% (95% CI: 88.3%-97.7%) in the independent validation set when distinguishing MIS-C from KD, DB, and DV., Conclusions: MIS-C can be distinguished from KD, DB, and DV groups using a 5-gene blood RNA expression signature. The small number of genes in the signature and good performance in both discovery and validation sets should enable the development of a diagnostic test for MIS-C., (© The Author(s) 2023. Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society.)
- Published
- 2023
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7. Mortality among rough sleepers, squatters, residents of homeless shelters or hotels and sofa-surfers: a pooled analysis of UK birth cohorts.
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White J, Fluharty M, de Groot R, Bell S, and Batty GD
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- Birth Cohort, Child, Cohort Studies, Humans, United Kingdom epidemiology, Ill-Housed Persons, Transients and Migrants
- Abstract
Background: Homelessness encompasses a wide spectrum of experience. Rough sleepers and people attending homeless shelters have been found to be at an increased risk of mortality. It is unclear whether risks are also elevated in those squatting, living temporarily in low-cost hotels or 'sofa-surfing' with friends or family members. This study examines mortality in a representative nationwide sample of people who have slept rough, squatted, lived in shelters or low-cost hotels and sofa-surfed., Methods: Using unpublished data from two national birth cohorts, namely the National Child Development Study and the 1970 British Birth Cohort study, Cox proportional-hazards models and random-effects meta-analyses were used to analyse associations between homelessness and different types of homeless experience (rough sleeping, squatting, staying in a homeless shelter or low-cost hotel, and sofa-surfing) and mortality., Results: Out of the 23 678 participants, 1444 (6.1%) reported having been homeless and 805 (3.4%) deaths occurred. Homelessness was associated with an increased risk of mortality [hazard ratio (HR) 1.68, 95% confidence interval (CI) 1.24-2.26]. Mortality risk was raised across the spectrum of homeless experience, from sleeping rough (HR 4.71, 95% CI 2.38-9.30), to squatting (HR 6.35, 95% CI 2.73-14.75), staying in a homeless shelter (HR 4.89, 95% CI 2.36-10.11), staying in a low-cost hotel (HR 3.38, 95% CI 1.30-8.79 through to sofa-surfing (HR 2.86, 95% CI 1.84-4.42). Associations remained after separate control for socio-economic status, mental health, substance use, accidents and assaults, and criminality., Conclusions: Mortality rates were raised across all types of homeless experience. This included squatting and sofa-surfing that have not previously been reported. Studies that have omitted the less severe, but more prevalent, use of low-cost hotels and sofa-surfing may have underestimated the impacts of homelessness on mortality., (© The Author(s) 2021. Published by Oxford University Press on behalf of the International Epidemiological Association.)
- Published
- 2022
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8. Impact of a clinical decision rule on antibiotic prescription for children with suspected lower respiratory tract infections presenting to European emergency departments: a simulation study based on routine data.
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Hagedoorn NN, Wagenaar JHL, Nieboer D, Bath D, Von Both U, Carrol ED, Eleftheriou I, Emonts M, Van Der Flier M, De Groot R, Herberg J, Kohlmaier B, Levin M, Lim E, Maconochie I, Martinon-Torres F, Nijman R, Pokorn M, Rivero Calle I, Tsolia M, Yeung S, Zavadska D, Zenz W, Vermont CL, Oostenbrink R, and Moll HA
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- Child, Clinical Decision Rules, Emergency Service, Hospital, Europe, Humans, Netherlands, Retrospective Studies, Anti-Bacterial Agents therapeutic use, Respiratory Tract Infections drug therapy
- Abstract
Background: Discriminating viral from bacterial lower respiratory tract infections (LRTIs) in children is challenging thus commonly resulting in antibiotic overuse. The Feverkidstool, a validated clinical decision rule including clinical symptoms and C-reactive protein, safely reduced antibiotic use in children at low/intermediate risk for bacterial LRTIs in a multicentre trial at emergency departments (EDs) in the Netherlands., Objectives: Using routine data from an observational study, we simulated the impact of the Feverkidstool on antibiotic prescriptions compared with observed antibiotic prescriptions in children with suspected LRTIs at 12 EDs in eight European countries., Methods: We selected febrile children aged 1 month to 5 years with respiratory symptoms and excluded upper respiratory tract infections. Using the Feverkidstool, we calculated individual risks for bacterial LRTI retrospectively. We simulated antibiotic prescription rates under different scenarios: (1) applying effect estimates on antibiotic prescription from the trial; and (2) varying both usage (50%-100%) and compliance (70%-100%) with the Feverkidstool's advice to withhold antibiotics in children at low/intermediate risk for bacterial LRTI (≤10%)., Results: Of 4938 children, 4209 (85.2%) were at low/intermediate risk for bacterial LRTI. Applying effect estimates from the trial, the Feverkidstool reduced antibiotic prescription from 33.5% to 24.1% [pooled risk difference: 9.4% (95% CI: 5.7%-13.1%)]. Simulating 50%-100% usage with 90% compliance resulted in risk differences ranging from 8.3% to 15.8%. Our simulations suggest that antibiotic prescriptions would be reduced in EDs with high baseline antibiotic prescription rates or predominantly (>85%) low/intermediate-risk children., Conclusions: Implementation of the Feverkidstool could reduce antibiotic prescriptions in children with suspected LRTIs in European EDs., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)
- Published
- 2021
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9. A hybrid treatment modality of a subtrochanteric femoral fracture in a patient with osteoporosis due to a renal Fanconi syndrome: a case report.
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Lange SF, Schrooten TKJ, de Wit RJ, and de Groot R
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A 24-year-old male with an idiopathic renal Fanconi syndrome presented to our ER after a low-energetic fall. Conventional imaging revealed a right subtrochanteric femoral fracture, severely decreased bone quality and cannulated collum femoris screws on the contralateral side. Regular plate-screw osteosynthesis or cephalomedullary implantation was deemed insufficient, due to a high iatrogenic and periprosthetic fracture probability. The decision was made to perform a plate-screw osteosynthesis combined with an intramedullary polymer bone enhancement (IlluminOss), to minimize this risk. No complications occurred perioperatively. The patient was able to walk independently two months postoperatively. This case shows that use of polymer implant as an enhancement of osteosynthesis in repair of fractures in the Fanconi syndrome is a safe and possible useful treatment method., (Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author(s) 2020.)
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- 2020
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10. Multi-component meningococcal serogroup B (MenB)-4C vaccine induces effective opsonophagocytic killing in children with a complement deficiency.
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van den Broek B, van Els CACM, Kuipers B, van Aerde K, Henriet SS, de Groot R, de Jonge MI, Langereis JD, and van der Flier M
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- Adolescent, Adult, Antibodies, Bacterial immunology, Child, Complement Factor H immunology, Complement Factor H metabolism, Female, Hereditary Complement Deficiency Diseases microbiology, Hereditary Complement Deficiency Diseases therapy, Humans, Male, Meningitis, Meningococcal microbiology, Meningitis, Meningococcal therapy, Meningococcal Vaccines administration & dosage, Neisseria meningitidis, Serogroup B physiology, Opsonin Proteins metabolism, Vaccination, Hereditary Complement Deficiency Diseases immunology, Meningitis, Meningococcal immunology, Meningococcal Vaccines immunology, Neisseria meningitidis, Serogroup B immunology, Opsonin Proteins immunology, Phagocytosis immunology
- Abstract
Vaccination against meningococcal serogroup B is recommended for patients with a complement deficiency; however, although immunogenicity in this patient group has been shown, efficacy has not yet been established. In this study, we collected serum from children with a complement deficiency in the alternative pathway or in late terminal pathway before and after vaccination with multi-component meningococcal serogroup B (MenB)-4C. MenB-4C is a multi-component, protein-based vaccine against MenB consisting of factor H-binding protein, Neisserial heparin-binding protein, Neisserial adhesion A and outer membrane vesicles containing Porin A. We assessed the vaccine immunogenicity and vaccine-mediated protection by a whole cell enzyme-linked immunosorbent assay with Neisseria meningitidis serogroup B strains H44/76, 5/99 and NZ98/254, which shows that vaccination induced antibody titers against meningococcus. We show that the classical serum bactericidal activity assay with exogenous serum indicates the presence of vaccine-induced antibodies and capacity to activate complement-mediated pathogen lysis. However, in children with a late terminal pathway deficiency, no complement-mediated pathogen lysis was observed when autologous serum was applied in the serum bactericidal activity assay, demonstrating a lack of serum bactericidal activity in children with complement deficiencies. However, MenB-4C vaccination still induced effective complement-dependent opsonophagocytic killing against N. meningitidis serogroup B in reconstituted whole blood with autologous serum from children with an alternative pathway or late terminal pathway deficiency. These findings support the recommendation to vaccinate all complement-deficient children against MenB., (© 2019 The Authors. Clinical & Experimental Immunology published by John Wiley & Sons Ltd on behalf of British Society for Immunology.)
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- 2019
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11. What factors explain socioeconomic inequalities in adults' television-related sitting time?
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Mackenbach JD, de Groot R, Lakerveld J, De Cocker K, Cardon G, De Bourdeaudhuij I, and Compernolle S
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- Adult, Aged, Attitude, Belgium, Body Mass Index, Cross-Sectional Studies, Environment, Female, Humans, Male, Middle Aged, Self Efficacy, Social Environment, Socioeconomic Factors, Educational Status, Occupations statistics & numerical data, Sedentary Behavior, Television statistics & numerical data
- Abstract
Background: There are considerable socioeconomic inequalities in television-related sitting time, but there is little evidence for the explanatory mechanisms. We used a cohort of Belgian adults (25-60 years) and older adults (≥65 years) to examine the social cognitive, home environmental and health-related factors contributing to socioeconomic differences in television-related sitting., Methods: We included 301 adults and 258 older adults (total n = 559). Linear regression analyses were used to examine the associations of education and occupational status with television-related sitting time, adjusted for age and gender. We assessed the explanatory power of social cognitive, home environmental and health-related factors using the traditional 'change-in-estimation method'., Results: Those with low and medium education, respectively, engaged in 54 and 28 minutes per day more television-related sitting time than those with high education. We found no association between occupational status and television-related sitting time. Social cognitive factors explained 54% of the difference in television-related sitting time between those with low and high education, while home environmental factors only explained 6%, and health-related variables explained 10% of these differences., Conclusion: We found no occupational inequalities in television-related sitting time. Social cognitive variables such as attitude and modelling of the partner explained a large part of the educational inequalities in television-related sitting time. If confirmed by future studies, a focus on social cognition may help reduce sedentary behaviours in low-educated adults and diminish inequalities in sedentary behaviours., (© The Author(s) 2018. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.)
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- 2019
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12. Fish and seafood consumption during pregnancy and the risk of asthma and allergic rhinitis in childhood: a pooled analysis of 18 European and US birth cohorts.
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Stratakis N, Roumeliotaki T, Oken E, Ballester F, Barros H, Basterrechea M, Cordier S, de Groot R, den Dekker HT, Duijts L, Eggesbø M, Fantini MP, Forastiere F, Gehring U, Gielen M, Gori D, Govarts E, Inskip HM, Iszatt N, Jansen M, Kelleher C, Mehegan J, Moltó-Puigmartí C, Mommers M, Oliveira A, Olsen SF, Pelé F, Pizzi C, Porta D, Richiardi L, Rifas-Shiman SL, Robinson SM, Schoeters G, Strøm M, Sunyer J, Thijs C, Vrijheid M, Vrijkotte TGM, Wijga AH, Kogevinas M, Zeegers MP, and Chatzi L
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- Animals, Child, Child, Preschool, Cohort Studies, Europe epidemiology, Female, Humans, Infant, Infant, Newborn, Male, Pregnancy, Prevalence, Regression Analysis, Respiratory Sounds, Surveys and Questionnaires, United States epidemiology, Asthma epidemiology, Fatty Acids, Omega-3 administration & dosage, Prenatal Nutritional Physiological Phenomena, Rhinitis, Allergic epidemiology, Seafood
- Abstract
Background: It has been suggested that prenatal exposure to n-3 long-chain fatty acids protects against asthma and other allergy-related diseases later in childhood. The extent to which fish intake in pregnancy protects against child asthma and rhinitis symptoms remains unclear. We aimed to assess whether fish and seafood consumption in pregnancy is associated with childhood wheeze, asthma and allergic rhinitis., Methods: We pooled individual data from 60 774 mother-child pairs participating in 18 European and US birth cohort studies. Information on wheeze, asthma and allergic rhinitis prevalence was collected using validated questionnaires. The time periods of interest were: infancy (0-2 years), preschool age (3-4 years), and school age (5-8 years). We used multivariable generalized models to assess associations of fish and seafood (other than fish) consumption during pregnancy with child respiratory outcomes in cohort-specific analyses, with subsequent random-effects meta-analyses., Results: The median fish consumption during pregnancy ranged from 0.44 times/week in The Netherlands to 4.46 times/week in Spain. Maternal fish intake during pregnancy was not associated with offspring wheeze symptoms in any age group nor with the risk of child asthma [adjusted meta-analysis relative risk (RR) per 1-time/week = 1.01, 95% confidence interval 0.97-1.05)] and allergic rhinitis at school age (RR = 1.01, 0.99-1.03). These results were consistently found in further analyses by type of fish and seafood consumption and in sensitivity analyses., Conclusion: We found no evidence supporting a protective association of fish and seafood consumption during pregnancy with offspring symptoms of wheeze, asthma and allergic rhinitis from infancy to mid childhood., (© The Author 2017; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association)
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- 2017
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13. Complement Factor H Serum Levels Determine Resistance to Pneumococcal Invasive Disease.
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van der Maten E, Westra D, van Selm S, Langereis JD, Bootsma HJ, van Opzeeland FJ, de Groot R, Ruseva MM, Pickering MC, van den Heuvel LP, van de Kar NC, de Jonge MI, and van der Flier M
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- Animals, Complement C3 immunology, Complement Factor H immunology, Disease Resistance immunology, Female, Humans, Male, Mice, Mice, Inbred C57BL, Pneumococcal Infections prevention & control, Pneumococcal Infections immunology
- Abstract
Streptococcus pneumoniae is a major cause of life-threatening infections. Complement activation plays a vital role in opsonophagocytic killing of pneumococci in blood. Initial complement activation via the classical and lectin pathways is amplified through the alternative pathway amplification loop. Alternative pathway activity is inhibited by complement factor H (FH). Our study demonstrates the functional consequences of the variability in human serum FH levels on host defense. Using an in vivo mouse model combined with human in vitro assays, we show that the level of serum FH correlates with the efficacy of opsonophagocytic killing of pneumococci. In summary, we found that FH levels determine a delicate balance of alternative pathway activity, thus affecting the resistance to invasive pneumococcal disease. Our results suggest that variation in FH expression levels, naturally occurring in the human population, plays a thus far unrecognized role in the resistance to invasive pneumococcal disease., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)
- Published
- 2016
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14. An evaluation of salt screening methodologies.
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Fernández Casares A, Nap WM, Ten Figás G, Huizenga P, Groot R, and Hoffmann M
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- Aripiprazole chemistry, Crystallization, Desvenlafaxine Succinate chemistry, Humans, Hydrogen-Ion Concentration, Solubility, Water chemistry, Chemistry, Pharmaceutical methods, Pharmaceutical Preparations chemistry, Salts chemistry, Technology, Pharmaceutical methods
- Abstract
Objectives: In this study, the advantages and disadvantages of three salt screening methodologies have been explored, and recommendations are put forward as to when each method is most appropriate., Methods: Three salt screening methodologies have been investigated: the in-situ salt screen, the saturated solution or rational screen approach, and the cooling-evaporative or high-throughput method. Two Active Pharmaceutical Ingredients (APIs) with significant differences in aqueous solubility have been chosen for this study, namely aripiprazole and desvenlafaxine (see Figure 1)., Key Findings: The in-situ salt formation screen appears to be a good method for early stage salt selection based on aqueous solubility, although this approach does not work for all APIs, as demonstrated in the comparison between aripiprazole and desvenlafaxine. The saturated solution method or rational approach demonstrated a valuable overview of the different salts that can be formed in an efficient and cost-effective manner. The cooling-evaporative screening method involved a complete examination of salt formation, including indication of polymorphism of the salts produced., Conclusions: The three salt formation approaches are methods that deliver crystalline salts. The choice of salt screen approach depends on the physical properties of the drug substance, development stage and objective of the screen., (© 2015 Royal Pharmaceutical Society.)
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- 2015
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15. Viral dsRNA-activated human dendritic cells produce IL-27, which selectively promotes cytotoxicity in naive CD8+ T cells.
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de Groot R, van Beelen AJ, Bakdash G, Taanman-Kueter EW, de Jong EC, and Kapsenberg ML
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- CD8-Positive T-Lymphocytes cytology, CD8-Positive T-Lymphocytes metabolism, Cell Differentiation immunology, Dendritic Cells metabolism, Humans, Interleukins immunology, Lymphocyte Activation immunology, Real-Time Polymerase Chain Reaction, Reverse Transcriptase Polymerase Chain Reaction, CD8-Positive T-Lymphocytes immunology, Cytotoxicity, Immunologic immunology, Dendritic Cells immunology, Interleukins biosynthesis, RNA, Double-Stranded immunology, RNA, Viral immunology
- Abstract
Viral recognition programs DCs to express Signal 3 molecules that promote the differentiation of effector CD8(+) T cells. Besides IL-12, another DC-derived IL-12 family member, IL-27, has been reported to contribute herein, but its specific role is not well understood. Here, we show that whereas IL-12 potently induces inflammatory cytokines (i.e., IFN-γ and TNF-α, but not IL-2), IL-27 excels in inducing proliferation and a cytotoxic profile (GrB, cytotoxicity of target cells) in human naïve CD8(+) T cells. Compared with bacterial cell-wall peptidoglycan, viral dsRNA-mimic poly (I:C) is superior in priming human BDCA1(+) peripheral blood DCs to produce IL-12 and IL-27, which promote inflammatory cytokines and a cytotoxic profile in differentiating CD8(+) T cells, respectively. These data support the concept that viral dsRNA-activated human DCs produce IL-27 to act as a specialized procytotoxic, antiviral cytokine in the development of effector CD8(+) T cells.
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- 2012
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16. Economic evaluation of targeted treatments of invasive aspergillosis in adult haematopoietic stem cell transplant recipients in the Netherlands: a modelling approach.
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Ament AJ, Hübben MW, Verweij PE, de Groot R, Warris A, Donnelly JP, van 't Wout J, and Severens JL
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- Amphotericin B therapeutic use, Caspofungin, Cost-Benefit Analysis, Costs and Cost Analysis, Data Interpretation, Statistical, Decision Trees, Drug Combinations, Echinocandins economics, Echinocandins therapeutic use, Humans, Lipopeptides, Models, Economic, Models, Statistical, Netherlands epidemiology, Pyrimidines economics, Pyrimidines therapeutic use, Reproducibility of Results, Survival Analysis, Triazoles economics, Triazoles therapeutic use, Voriconazole, Antifungal Agents economics, Antifungal Agents therapeutic use, Aspergillosis drug therapy, Aspergillosis economics, Hematopoietic Stem Cell Transplantation
- Abstract
Objectives: The aim of this study was to assess the cost-effectiveness of a targeted treatment model of antifungal treatment strategies for adult haematopoietic stem cell transplant (HSCT) recipients in the Netherlands from a hospital perspective, using a decision analytic modelling approach., Methods: The economic evaluation of desoxycholate amphotericin B, liposomal amphotericin B, voriconazole and caspofungin was undertaken. These drugs could be used alone, in various combinations or sequentially. In our model, first-line therapy consisted of either voriconazole or liposomal amphotericin B. If necessary, treatment was switched to a second-line treatment, including combination antifungal therapy. The theoretical population in this model consisted of adult HSCT recipients with proven or probable invasive aspergillosis (IA). Long-term survival was extrapolated from survival after 12 weeks of treatment and life expectancy., Results: First-line antifungal treatment strategies with voriconazole were both more effective and less costly over first-line strategies employing liposomal amphotericin B at a dosage of 4 mg/kg/day. The strategy of voriconazole followed by caspofungin (voriconazole/caspofungin) was dominant over the strategies of voriconazole followed by liposomal amphotericin B (voriconazole/liposomal amphotericin B) or desoxycholate amphotericin B (voriconazole/desoxycholate amphotericin B). However, the voriconazole followed by the combination of liposomal amphotericin B and caspofungin strategy (voriconazole/liposomal amphotericin B+caspofungin) was more effective though more expensive than the voriconazole/caspofungin strategy resulting in an incremental cost-effectiveness ratio (ICER) of about euro107,000 for a life-year saved. At a dosage of 1 mg/kg/day of liposomal amphotericin B, the voriconazole/caspofungin strategy was more effective but more costly than the voriconazole/desoxycholate amphotericin B strategy with an ICER of euro10,000 for each extra life-year saved. Between the voriconazole/liposomal amphotericin B+caspofungin and the voriconazole/caspofungin strategies, the ICER was euro40,000., Conclusions: Probabilistic analyses on net monetary benefit showed that the voriconazole/caspofungin strategy had the highest probability of being the most cost-effective strategy.
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- 2007
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17. Epidemiology of nasopharyngeal carriage of Neisseria meningitidis in healthy Dutch children.
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Bogaert D, Hermans PW, Boelens H, Sluijter M, Luijendijk A, Rumke HC, Koppen S, van Belkum A, de Groot R, and Verbrugh HA
- Subjects
- Adolescent, Adult, Aging, Child, Child, Preschool, Female, Humans, Incidence, Infant, Male, Netherlands epidemiology, Odds Ratio, Prevalence, Risk Factors, Carrier State, Meningococcal Infections epidemiology, Nasopharynx microbiology, Neisseria meningitidis isolation & purification
- Abstract
We investigated the prevalence and determinants of nasopharyngeal carriage of Neisseria meningitidis in 3200 healthy children aged 1-19 years. The incidence of meningococcal carriage was, on average, 1.5%. Peak incidences were seen at age 1 year and after age 15 years. The independent determinants of meningococcal carriage included age, regular visits to youth clubs (odds ratio [OR], 2.2) and discotheques (OR, 4.3), and pneumococcal carriage (OR, 4.1).
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- 2005
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18. Sustained viral suppression and immune recovery in HIV type 1-infected children after 4 years of highly active antiretroviral therapy.
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Fraaij PL, Verweel G, van Rossum AM, van Lochem EG, Schutten M, Weemaes CM, Hartwig NG, Burger DM, and de Groot R
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- Adolescent, CD4 Lymphocyte Count, Child, Child, Preschool, Cohort Studies, Female, HIV Infections virology, Humans, Male, Prospective Studies, Time Factors, Treatment Outcome, Antiretroviral Therapy, Highly Active methods, HIV Infections drug therapy, HIV Infections immunology, HIV-1 drug effects, RNA, Viral blood
- Abstract
We report the data from a long-term study of 31 human immunodeficiency virus type 1 (HIV-1)-infected children who were treated with highly active antiretroviral therapy. A high proportion of the children had undetectable HIV-1 RNA levels. CD4+ T cell counts recovered and remained stable. Adverse events were observed frequently but were mostly mild.
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- 2005
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19. Plasma levels of zidovudine twice daily compared with three times daily in six HIV-1-infected children.
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Bergshoeff AS, Fraaij PL, Verweij C, van Rossum AM, Verweel G, Hartwig NG, de Groot R, and Burger DM
- Subjects
- Adolescent, Anti-HIV Agents administration & dosage, Anti-HIV Agents therapeutic use, Area Under Curve, Child, Child, Preschool, Drug Administration Schedule, Female, HIV Infections virology, HIV-1 drug effects, Humans, Infant, Male, Reverse Transcriptase Inhibitors administration & dosage, Reverse Transcriptase Inhibitors therapeutic use, Zidovudine administration & dosage, Zidovudine therapeutic use, Anti-HIV Agents pharmacokinetics, HIV Infections drug therapy, Reverse Transcriptase Inhibitors pharmacokinetics, Zidovudine pharmacokinetics
- Abstract
Objectives: Zidovudine is often administered every 12 h in HIV-infected children, but so far no pharmacokinetic data are available for the administration of this agent every 12 h. We have evaluated the plasma pharmacokinetics of zidovudine administered every 8 h versus every 12 h in HIV-1-infected children., Methods: In HIV-1-infected children who switched from zidovudine every 8 h to every 12 h, a pharmacokinetic curve was recorded both before and after the switch. Zidovudine plasma levels were measured by HPLC. Pharmacokinetic parameters were calculated by non-compartmental methods., Results: Six HIV-1-infected children [median age (range) 7.8 (2.5-13.4) years] were included. In these patients, geometric mean ratios of AUC(0-24) and C(max) for zidovudine every 12 h versus every 8 h were not significantly different from 1.0., Conclusions: The plasma pharmacokinetic parameters of zidovudine taken every 8 h and every 12 h were not significantly different and therefore suggest bioequivalence of these two dose frequencies.
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- 2004
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20. Nasopharyngeal pneumococcal carriage after combined pneumococcal conjugate and polysaccharide vaccination in children with a history of recurrent acute otitis media.
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Veenhoven RH, Bogaert D, Schilder AG, Rijkers GT, Uiterwaal CS, Kiezebrink HH, van Kempen MJ, Dhooge IJ, Bruin J, Ijzerman EP, de Groot R, Kuis W, Hermans PW, and Sanders EA
- Subjects
- Aging, Child, Child, Preschool, Double-Blind Method, Female, Humans, Infant, Male, Vaccines, Conjugate immunology, Carrier State microbiology, Nasopharynx microbiology, Otitis Media complications, Pneumococcal Vaccines immunology, Streptococcus pneumoniae isolation & purification
- Abstract
Background: We recently showed that vaccination with a 7-valent pneumococcal conjugate vaccine (PCV7) followed by a 23-valent pneumococcal polysaccharide vaccine (PPSV23) failed to prevent new episodes of acute otitis media (AOM) in previously unvaccinated toddlers and children with a history of recurrent AOM. We describe in detail the impact of pneumococcal vaccinations on nasopharyngeal carriage of S. pneumoniae in this study population., Methods: The impact of vaccination with PCV7 followed by PPSV23 on pneumococcal nasopharyngeal carriage was studied in a prospective, randomized trial involving 383 children (age range, 1-7 years) with previous AOM. Nasopharyngeal swab specimens were collected at the time of first vaccination and at 6-7-month intervals during the 26-month follow-up period., Results: Overall, pneumococcal carriage rates did not diminish, remaining at approximately 50% in both PCV7/PPSV23 and control vaccinees. A significant shift from conjugate vaccine- to nonconjugate vaccine-type pneumococci was observed in children aged 1-2 years, who received the conjugate vaccine twice before the polysaccharide vaccine was administered. Conjugate vaccine serotype carriage was not influenced in older children, who received the conjugate vaccine once before receiving the polysaccharide booster., Conclusions: The administration of conjugate vaccines at least twice also after 2 years of age may be mandatory for reducing the carriage of conjugate vaccine serotypes in children with recurrent AOM. Polysaccharide booster vaccination did not affect nasopharyngeal colonization with serotypes not included in the conjugate vaccine.
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- 2004
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21. Prevalence and clinical symptoms of human metapneumovirus infection in hospitalized patients.
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van den Hoogen BG, van Doornum GJ, Fockens JC, Cornelissen JJ, Beyer WE, de Groot R, Osterhaus AD, and Fouchier RA
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- Adolescent, Adult, Age Factors, Aged, Child, Child, Preschool, Female, Humans, Immunocompromised Host, Infant, Male, Metapneumovirus genetics, Middle Aged, Netherlands epidemiology, Paramyxoviridae Infections pathology, Prevalence, Respiratory Syncytial Virus Infections pathology, Respiratory Syncytial Virus Infections virology, Respiratory Syncytial Viruses isolation & purification, Respiratory Tract Infections pathology, Retrospective Studies, Seasons, Metapneumovirus isolation & purification, Paramyxoviridae Infections epidemiology, Paramyxoviridae Infections virology, Respiratory Tract Infections epidemiology, Respiratory Tract Infections virology
- Abstract
During a 17-month period, we performed retrospective analyses of the prevalence of and clinical symptoms associated with human metapneumovirus (hMPV) infection, among patients in a university hospital in The Netherlands. All available nasal-aspirate, throat-swab, sputum, and bronchoalveolar-lavage samples (N=1515) were tested for hMPV RNA by reverse-transcriptase polymerase chain reaction. hMPV RNA was detected in 7% of samples from patients with respiratory tract illnesses (RTIs) and was the second-most-detected viral pathogen in these patients during the last 2 winter seasons. hMPV was detected primarily in very young children and in immunocompromised individuals. In young children, clinical symptoms associated with hMPV infection were similar to those associated with human respiratory syncytial virus (hRSV) infection, but dyspnea, feeding difficulties, and hypoxemia were reported more frequently in hRSV-infected children. Treatment with antibiotics and corticosteroids was reported more frequently in hMPV-infected children. From these data, we conclude that hMPV is an important pathogen associated with RTI.
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- 2003
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22. Changes in indinavir exposure over time: a case study in six HIV-1-infected children.
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Fraaij PL, Bergshoeff AS, van Rossum AM, Hartwig NG, Burger DM, and de Groot R
- Subjects
- Adolescent, Area Under Curve, Case-Control Studies, Child, Child, Preschool, Female, HIV Infections metabolism, Humans, Indinavir pharmacokinetics, Indinavir pharmacology, Infant, Male, Time Factors, HIV Infections drug therapy, HIV-1 drug effects, Indinavir therapeutic use
- Abstract
Objective: To study changes in indinavir exposure over time in HIV-1-infected children., Materials and Methods: Protease inhibitor (PI)-naive HIV-1-infected children were treated with indinavir, zidovudine and lamivudine. Steady-state plasma pharmacokinetic (PK) sampling was carried out as standard of care. The AUC(0-8) was targeted between 15 and 30 mg h/L. PK sampling was repeated after dosage adjustment until the AUC(0-8) reached target values. Patients were included when the time interval between PK samplings was > or =2 years and differences in dosage/m2 <10% between PK samplings 1 and 2. Corrections of dose for changes in body size were carried out., Results: Six children were enrolled with a median age of 5.2 years (range 1.7-13.6 years). All had a viral load below 500 copies/mL. The geometric mean (GM) of the AUC(0-8) decreased from 25.3 mg h/L at the first PK-day to 19.1 mg h/L at the second PK-day [geometric mean ratio (GMR): 0.76 (95% C.I.: 0.48-1.20)]. The GM of Cmax decreased from 11.8 to 10.4 mg/L [GMR: 0.88 (95% C.I.: 0.59-1.32)]. The GM of Cmin decreased from 0.08 to 0.07 mg/L [GMR: 0.86 (95% C.I.: 0.62-1.18)]. All children had an AUC(0-8) above 15 mg h/L on the first PK-day; three had an AUC(0-8) below 15 mg h/L on the second PK-day. In two of these three children, the plasma viral load was >500 copies/mL., Conclusion: Changes in indinavir exposure were observed over time. In two patients, decreased indinavir exposure was associated with virological failure. Therapeutic drug monitoring should be carried out over time since this may prevent subtherapeutic dosing in children.
- Published
- 2003
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23. Results of 2 years of treatment with protease-inhibitor--containing antiretroviral therapy in dutch children infected with human immunodeficiency virus type 1.
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van Rossum AM, Geelen SP, Hartwig NG, Wolfs TF, Weemaes CM, Scherpbier HJ, van Lochem EG, Hop WC, Schutten M, Osterhaus AD, Burger DM, and de Groot R
- Subjects
- Adolescent, CD4 Lymphocyte Count, Child, Child, Preschool, Drug Therapy, Combination, Female, HIV Infections epidemiology, HIV Protease Inhibitors adverse effects, HIV-1 drug effects, Humans, Indinavir adverse effects, Indinavir therapeutic use, Infant, Lamivudine adverse effects, Lamivudine therapeutic use, Male, Nelfinavir adverse effects, Nelfinavir therapeutic use, Netherlands epidemiology, Prospective Studies, Reverse Transcriptase Inhibitors adverse effects, Treatment Outcome, Zidovudine adverse effects, Zidovudine therapeutic use, HIV Infections drug therapy, HIV Protease Inhibitors therapeutic use, Reverse Transcriptase Inhibitors therapeutic use
- Abstract
Clinical, virologic, and immunologic responses to treatment that contained either indinavir or nelfinavir (both regimens included zidovudine and lamivudine) were determined in 32 children infected with human immunodeficiency virus type 1 (HIV-1) who participated for >/= 96 weeks in a prospective, open, uncontrolled multicenter trial. The pharmacokinetics of indinavir and of nelfinavir were determined and showed large interindividual differences. After 96 weeks of therapy, 69% and 50% of the patients had an HIV-1 RNA load that was below the HIV assays' detection limits of 500 and 40 copies/mL, respectively. Virologic failure was associated with poor compliance and younger age (independent of baseline virus load and receipt of pretreatment). Relative CD4 cell counts increased significantly in relation to the median of the age-specific reference value, from a median of 44% at baseline to 94% after 96 weeks. In a high percentage of the children, clinical, virologic, and immunologic response rates to combination therapy were optimal during the initial 2 years of therapy.
- Published
- 2002
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24. Safety and immunogenicity of a novel recombinant subunit respiratory syncytial virus vaccine (BBG2Na) in healthy young adults.
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Power UF, Nguyen TN, Rietveld E, de Swart RL, Groen J, Osterhaus AD, de Groot R, Corvaia N, Beck A, Bouveret-Le-Cam N, and Bonnefoy JY
- Subjects
- Adolescent, Adult, Antibodies, Viral biosynthesis, Antigens, Viral adverse effects, Antigens, Viral immunology, Epitopes immunology, Humans, Middle Aged, Peptides immunology, Recombinant Proteins adverse effects, Recombinant Proteins immunology, Respiratory Syncytial Virus Infections etiology, Respiratory Tract Infections etiology, Vaccines, Subunit adverse effects, Vaccines, Subunit immunology, Viral Proteins adverse effects, Viral Proteins immunology, Respiratory Syncytial Virus Vaccines adverse effects, Respiratory Syncytial Virus Vaccines immunology
- Abstract
A novel recombinant respiratory syncytial virus (RSV) subunit vaccine, designated BBG2Na, was administered to 108 healthy adults randomly assigned to receive 10, 100, or 300 microg of BBG2Na in aluminum phosphate or saline placebo. Each subject received 1, 2, or 3 intramuscular injections of the assigned dose at monthly intervals. Local and systemic reactions were mild, and no evidence of harmful properties of BBG2Na was reported. The highest ELISA and virus-neutralizing (VN) antibody responses were evident in the 100- and 300-microg groups; second or third injections provided no significant boosts against RSV-derived antigens. BBG2Na induced > or 2-fold and > or =4-fold increases in G2Na-specific ELISA units in up to 100% and 57% of subjects, respectively; corresponding RSV-A-specific responses were 89% and 67%. Furthermore, up to 71% of subjects had > or =2-fold VN titer increases. Antibody responses to 2 murine lung protective epitopes were also highly boosted after vaccination. Therefore, BBG2Na is safe, well tolerated, and highly immunogenic in RSV-seropositive adults.
- Published
- 2001
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25. Emergence of rifampin-resistant Streptococcus pneumoniae as a result of antimicrobial therapy for penicillin-resistant strains.
- Author
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van Tilburg PM, Bogaert D, Sluijter M, Jansz AR, de Groot R, and Hermans PW
- Subjects
- Amino Acid Sequence, Anti-Bacterial Agents therapeutic use, Cross Infection drug therapy, Cross Infection epidemiology, Cross Infection microbiology, DNA-Directed RNA Polymerases chemistry, DNA-Directed RNA Polymerases genetics, Humans, Molecular Sequence Data, Penicillin Resistance, Pneumococcal Infections drug therapy, Pneumococcal Infections epidemiology, Pulmonary Disease, Chronic Obstructive complications, Pulmonary Disease, Chronic Obstructive epidemiology, Rifampin therapeutic use, Streptococcus pneumoniae genetics, Anti-Bacterial Agents pharmacology, Drug Resistance, Multiple, Bacterial, Pneumococcal Infections microbiology, Rifampin pharmacology, Streptococcus pneumoniae drug effects
- Abstract
A multidrug-resistant strain of Streptococcus pneumoniae was isolated in The Netherlands during a nosocomial outbreak among 36 patients who mainly had chronic obstructive pulmonary disease. After the commencement of barrier nursing and short-term ceftriaxone-rifampin eradication therapy, the epidemic ceased. However, eradication therapy failed in 3 patients, and follow-up investigation of these patients showed the emergence of rifampin-resistant isolates.
- Published
- 2001
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26. Prevention of meningococcal serogroup B infections in children: a protein-based vaccine induces immunologic memory.
- Author
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de Kleijn ED, de Groot R, Lafeber AB, Labadie J, van Limpt CJ, Visser J, Berbers GA, van Alphen L, and Rümke HC
- Subjects
- Antibodies, Bacterial biosynthesis, Antibodies, Bacterial blood, Child, Child, Preschool, Female, Hepatitis B Vaccines immunology, Humans, Immunization, Secondary, Immunologic Memory drug effects, Male, Neisseria meningitidis, Immunologic Memory immunology, Meningitis, Meningococcal prevention & control, Meningococcal Vaccines immunology
- Abstract
Immunologic memory against meningococci was studied in 177 children (100 children were 10-11 years old and 77 were 5-6 years old) 2.5 years after vaccination with hexavalent meningococcal outer membrane vesicle (OMV) vaccine or hepatitis B (HepB) vaccine. Children were revaccinated with monovalent P1.7(h),4 meningococcal OMV vaccine. Serum bactericidal antibodies (SBAs) were measured before revaccination and after 4-6 weeks. A minimum 4-fold increase in SBAs against serosubtype P1.7(h),4 was detected in 48.5% of the children after hexavalent meningococcal vaccine and in 8.9% after HepB vaccine. Of the initial responders given hexavalent meningococcal vaccine, 78% had > or =4-fold increase in SBAs against strain P1.4. Thus, immunologic memory is present in toddlers and school-aged children previously given 3 hexavalent meningococcal vaccinations. Booster vaccination with monovalent P1.7(h),4 meningococcal OMV vaccine induces a significant increase in SBAs against serosubtype P1.7(h),4 and cross-reactivity against other serosubtypes in the hexavalent vaccine.
- Published
- 2001
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27. Efficacy, safety and tolerability of 3 day azithromycin versus 10 day co-amoxiclav in the treatment of children with acute lower respiratory tract infections.
- Author
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Ferwerda A, Moll HA, Hop WC, Kouwenberg JM, Tjon Pian Gi CV, Robben SG, and de Groot R
- Subjects
- Amoxicillin-Potassium Clavulanate Combination administration & dosage, Anti-Bacterial Agents administration & dosage, Anti-Bacterial Agents adverse effects, Azithromycin administration & dosage, Child, Child, Preschool, Double-Blind Method, Drug Therapy, Combination administration & dosage, Drug Therapy, Combination adverse effects, Female, Humans, Infant, Male, Treatment Outcome, Amoxicillin-Potassium Clavulanate Combination adverse effects, Amoxicillin-Potassium Clavulanate Combination therapeutic use, Anti-Bacterial Agents therapeutic use, Azithromycin adverse effects, Azithromycin therapeutic use, Drug Therapy, Combination therapeutic use, Respiratory Tract Infections drug therapy
- Abstract
To compare the efficacy, safety and tolerability of a 3 day course of azithromycin with a 10 day course of co-amoxiclav in the treatment of children with acute lower respiratory tract infection (LRTI), 118 patients with community-acquired LRTI were included in a multicentre randomized double-blind, double-dummy study. The diagnosis of LRTI was based on the presence of respiratory signs and symptoms in combination with consolidation on a chest radiograph or clinical evidence of LRTI. Patients received oral azithromycin suspension (10 mg/kg/24 h) or placebo in one dose for 3 days and co-amoxiclav (45/11.25 mg/kg/24 h) or placebo in three doses for 10 days. Of 110 eligible patients, 56 and 54 patients, respectively, were treated with azithromycin or co-amoxiclav. The percentage of patients cured or clinically improved at days 10-13 (primary endpoint) was 91% for azithromycin and 87% for co-amoxiclav. This difference of 4% (90% confidence interval: -6%, +14%) was not statistically significant (P= 0.55). Significantly (P = 0.01) more related adverse events were found in the co-amoxiclav group. This was largely due to a higher percentage (43% versus 19%) of gastrointestinal complaints. A 3 day course of azithromycin (three doses) is as effective in the treatment of LRTI in children as a 10 day course of co-amoxiclav (30 doses). The azithromycin group had fewer adverse events. We conclude that azithromycin is an effective, safe and well-tolerated drug in the treatment of children with LRTI. An additional advantage is the easy administration and short duration of therapy.
- Published
- 2001
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28. C/EBP regulates the promoter of the eosinophil-derived neurotoxin/RNS2 gene in human eosinophilic cells.
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Baltus B, Buitenhuis M, van Dijk TB, Vinson C, Raaijmakers JA, Lammers JW, Koenderman L, and de Groot RP
- Subjects
- Animals, Binding Sites, CCAAT-Enhancer-Binding Proteins, COS Cells, DNA-Binding Proteins genetics, Eosinophil-Derived Neurotoxin, Gene Expression Regulation, HL-60 Cells, Humans, Mutagenesis, Nuclear Proteins genetics, DNA-Binding Proteins metabolism, Eosinophils physiology, Nuclear Proteins metabolism, Promoter Regions, Genetic, Proteins genetics, Ribonucleases
- Abstract
The eosinophil-derived neurotoxin (EDN), a member of the mammalian ribonuclease family, is found in the large specific granules of human eosinophilic leukocytes. We have investigated the role of the C/EBP transcription factor family in the regulation of EDN promoter activity. Here we show that the C/EBP family is involved in intrinsic regulation of EDN promoter activity. We have identified a C/EBP binding site located at -124 in the proximal promoter of the EDN gene. Mutation of this C/EBP site results in a decrease of promoter activity in HL-60-eos cells as well as in eosinophils differentiated in vitro from CD34+ cells. Different C/EBP proteins are able to bind to the C/EBP site as shown by gel shift assay. Our results indicate the importance of the C/EBP family in the regulation of the EDN gene in eosinophils.
- Published
- 1999
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29. Efficacy and safety of the neuraminidase inhibitor zanamivirin the treatment of influenza A and B virus infections.
- Author
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Monto AS, Fleming DM, Henry D, de Groot R, Makela M, Klein T, Elliott M, Keene ON, and Man CY
- Subjects
- Adult, Antiviral Agents adverse effects, Double-Blind Method, Enzyme Inhibitors adverse effects, Enzyme Inhibitors therapeutic use, Female, Guanidines, Humans, Influenza, Human virology, Male, Neuraminidase antagonists & inhibitors, Pyrans, Sialic Acids adverse effects, Treatment Outcome, Zanamivir, Antiviral Agents therapeutic use, Influenza A virus, Influenza B virus, Influenza, Human drug therapy, Sialic Acids therapeutic use
- Abstract
The efficacy and safety of zanamivir, administered 2x or 4x daily over 5 days, was evaluated in the treatment of influenza infections. A total of 1256 patients entered the study; 57% of those randomized had laboratory-confirmed influenza infection. The primary end point, "alleviation of major symptoms," was created to evaluate differences in clinical impact. In the overall population with or without influenza infection, zanamivir reduced the median number of days to reach this end point by 1 day (P=.012 2x daily vs. placebo; P=.014 4x daily vs. placebo). The reduction was greater in patients treated within 30 h of symptom onset, febrile at study entry, and in defined high-risk groups. Zanamivir reduced nights of disturbed sleep, time to resumption of normal activities, and use of symptom relief medications. It was well tolerated. These results suggest that zanamivir can significantly reduce the duration and overall symptomatic effect of influenza.
- Published
- 1999
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30. Lineage-specific activation of STAT3 by interferon-gamma in human neutrophils.
- Author
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Caldenhoven E, Buitenhuis M, van Dijk TB, Raaijmakers JA, Lammers JW, Koenderman L, and de Groot RP
- Subjects
- Cell Differentiation, Cell Lineage, Cells, Cultured, HL-60 Cells, Humans, Janus Kinase 1, Janus Kinase 2, Protein-Tyrosine Kinases metabolism, STAT3 Transcription Factor, Signal Transduction drug effects, Antiviral Agents pharmacology, DNA-Binding Proteins metabolism, Interferon-gamma pharmacology, Neutrophils cytology, Neutrophils metabolism, Proto-Oncogene Proteins, Trans-Activators metabolism
- Abstract
Binding of interferon-gamma (IFN-gamma) to its heterodimeric receptor induces activation of the tyrosine kinases JAK1 and JAK2 followed by tyrosine phosphorylation of STAT1alpha. Selective activation of STAT1alpha at the IFN-gamma receptor is achieved by specific interaction between a cytosolic tyrosine motif including Y440 in the IFN-gamma receptor alpha-chain and the SH2 domain of STAT1alpha. We demonstrate that, in addition to STAT1alpha, STAT3 is also activated by IFN-gamma in human neutrophils. The activation of STAT3 was not found in human eosinophils, monocytes, and HL-60 cells, although the STAT3 protein was expressed in these cells. The cell type-specific activation of STAT3 by IFN-gamma was also observed in neutrophils that are differentiated in vitro from human CD34+ hematopoietic stem cells. These results indicate that a single cytokine receptor can activate different STAT family members in a cell-specific manner, which might result in cell-specific gene transcription.
- Published
- 1999
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31. Differences in N-acetylmuramyl-L-alanine amidase and lysozyme in serum and cerebrospinal fluid of patients with bacterial meningitis.
- Author
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Hoijer MA, de Groot R, van Lieshout L, Jacobs BC, Melief MJ, and Hazenberg MP
- Subjects
- Adolescent, Adult, Aged, Antigens, CD, Cell Degranulation, Cell Membrane metabolism, Child, Child, Preschool, Female, Flow Cytometry, GPI-Linked Proteins, Haemophilus Infections blood, Haemophilus Infections cerebrospinal fluid, Humans, Infant, Male, Membrane Glycoproteins analysis, Membrane Glycoproteins metabolism, Meningitis, Meningococcal blood, Meningitis, Meningococcal cerebrospinal fluid, Middle Aged, Neutrophil Activation, Neutrophils physiology, Pneumococcal Infections blood, Pneumococcal Infections cerebrospinal fluid, Antigens, Neoplasm, Cell Adhesion Molecules, Meningitis, Bacterial blood, Meningitis, Bacterial cerebrospinal fluid, Muramidase analysis, N-Acetylmuramoyl-L-alanine Amidase analysis
- Abstract
N-acetylmuramyl-L-alanine amidase (NAMLAA) specifically degrades peptidoglycan, a major component of bacterial cell walls. Lysozyme degrades peptidoglycan differently by hydrolyzing the aminosugar backbone of peptidoglycan. In another study, it was shown that the two enzymes act synergistically to inactivate the inflammatory properties of peptidoglycan. The presence of lysozyme and NAMLAA was determined in serum and cerebrospinal fluid (CSF) of patients with bacterial meningitis. High concentrations of lysozyme were found in CSF while, surprisingly, NAMLAA was not present. To explain this phenomenon, the degranulation pattern of neutrophils in CSF was compared with that of neutrophils from blood. Specific granules contain lysozyme and the azurophil granules contain both lysozyme and NAMLAA. CD66b expression on the cell surface, indicative for fusion of the specific granules with the cell membrane, was higher in CSF than in blood, while the marker for the azurophil granules was lower.
- Published
- 1998
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32. Differential activation of functionally distinct STAT5 proteins by IL-5 and GM-CSF during eosinophil and neutrophil differentiation from human CD34+ hematopoietic stem cells.
- Author
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Caldenhoven E, van Dijk TB, Tijmensen A, Raaijmakers JA, Lammers JW, Koenderman L, and de Groot RP
- Subjects
- Eosinophils cytology, Humans, Neutrophils cytology, STAT5 Transcription Factor, Antigens, CD34, DNA-Binding Proteins metabolism, Eosinophils drug effects, Granulocyte-Macrophage Colony-Stimulating Factor pharmacology, Hematopoiesis drug effects, Interleukin-5 pharmacology, Milk Proteins, Neutrophils drug effects, Trans-Activators metabolism
- Abstract
Interleukin-5 (IL-5) and granulocyte macrophage-colony stimulating factor (GM-CSF) are important cytokines for the proliferation, differentiation, and activation of myeloid lineages. The JAK/STAT pathway is one of the signaling pathways implicated in mediating biological responses induced by these cytokines. Previous studies have demonstrated that these cytokines predominantly activate an 80 kDa STAT5 isoform in mature granulocytes. To better understand the role of STAT proteins during growth and differentiation of granulocytes, we evaluated differentiation of human CD34+ hematopoietic stem cells ex vivo toward eosinophils and neutrophils. Bandshift experiments showed that in an early stage of both differentiation pathways (14 days), the 94 kDa STAT5B protein was activated by both IL-5 (eosinophil lineage) and GM-CSF (neutrophil lineage). However, during maturation of both lineages (days 21 and 28), increased expression of a functionally distinct 80 kDa STAT5 isoform was observed, resulting in heterodimer DNA-binding complexes containing both the 94 and 80 kDa STAT5 proteins. The finding that functionally distinct isoforms of STAT5 are activated during the early and late differentiation stages of granulocytes suggests that they might be involved in regulating different biological functions in these cells.
- Published
- 1998
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33. Meningococcal septic shock in children: clinical and laboratory features, outcome, and development of a prognostic score.
- Author
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Kornelisse RF, Hazelzet JA, Hop WC, Spanjaard L, Suur MH, van der Voort E, and de Groot R
- Subjects
- Adolescent, Alkalosis etiology, C-Reactive Protein metabolism, Child, Child, Preschool, Disseminated Intravascular Coagulation etiology, Female, Humans, Infant, Infant, Newborn, Logistic Models, Male, Meningococcal Infections complications, Meningococcal Infections mortality, Neisseria meningitidis classification, Netherlands epidemiology, Platelet Count, Potassium blood, Prognosis, Shock, Septic complications, Shock, Septic mortality, Meningococcal Infections blood, Shock, Septic blood
- Abstract
The clinical characteristics of and outcome for 75 children with meningococcal septic shock were studied. In addition, a new prognostic scoring system was developed. The median age of the patients was 3.2 years (range, 3 weeks to 17.9 years). The most common phenotype of Neisseria meningitidis was B:4:P1.4 (27%). A mortality rate of 21% was observed. Ten (17%) of the 59 survivors had serious sequelae. Calcium levels were significantly lower in patients with seizures. Disseminated intravascular coagulation occurred in 58% of the patients who were tested. Logistic regression analysis identified four laboratory features independently associated with mortality: serum C-reactive protein level, base excess, serum potassium level, and platelet count. These features were used to develop a novel scoring system with a predictive value for death and survival of 71% and 90%, respectively. The outcome was predicted correctly for 86% of the patients, which is higher than rates previously reported for scoring systems.
- Published
- 1997
- Full Text
- View/download PDF
34. Penicillin-resistant Streptococcus pneumoniae in the Netherlands: results of a 1-year molecular epidemiologic survey.
- Author
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Hermans PW, Sluijter M, Elzenaar K, van Veen A, Schonkeren JJ, Nooren FM, van Leeuwen WJ, de Neeling AJ, van Klingeren B, Verbrugh HA, and de Groot R
- Subjects
- Aged, Anti-Bacterial Agents pharmacology, Carrier Proteins genetics, Cross Infection microbiology, Disease Outbreaks, Genotype, Humans, Lung Diseases, Obstructive epidemiology, Lung Diseases, Obstructive microbiology, Microbial Sensitivity Tests, Molecular Epidemiology, Muramoylpentapeptide Carboxypeptidase genetics, Netherlands epidemiology, Penicillin-Binding Proteins, Phenotype, Pneumococcal Infections microbiology, Pneumococcal Infections transmission, Polymorphism, Restriction Fragment Length, Streptococcus pneumoniae genetics, Bacterial Proteins, Hexosyltransferases, Penicillin Resistance genetics, Peptidyl Transferases, Pneumococcal Infections epidemiology, Streptococcus pneumoniae drug effects
- Abstract
The molecular epidemiologic characteristics of penicillin-resistant pneumococci in the Netherlands were investigated in 1995. Dutch electronic surveillance data showed that 0.7% of all pneumococci were intermediately resistant and 0.4% were highly resistant to penicillin. From March 1995 to March 1996, 89 penicillin-resistant isolates were collected by 39 medical microbiology laboratories. Thirty different genotypes were observed by restriction fragment end labeling. Twenty-one DNA types were unique, whereas 9 distinct genotypes were shared by > or = 2 isolates. Different serogroups were found within 6 of the 9 genetically identical clusters of penicillin-resistant isolates, suggesting that horizontal transfer of capsular genes is common. Finally, nosocomial transmission of penicillin-resistant pneumococci was observed among 21 elderly adults with chronic obstructive pulmonary disease. This study demonstrates that multiple clones of penicillin-resistant pneumococci have been introduced in the Netherlands, a country with a low prevalence of pneumococcal infection. Some clones spread among the population in and outside hospitals.
- Published
- 1997
- Full Text
- View/download PDF
35. The role of nitric oxide in bacterial meningitis in children.
- Author
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Kornelisse RF, Hoekman K, Visser JJ, Hop WC, Huijmans JG, van der Straaten PJ, van der Heijden AJ, Sukhai RN, Neijens HJ, and de Groot R
- Subjects
- Adolescent, Anti-Inflammatory Agents pharmacology, Arginine blood, Arginine cerebrospinal fluid, Blood-Brain Barrier, Case-Control Studies, Child, Child, Preschool, Dexamethasone pharmacology, Female, Humans, Infant, Male, Meningitis, Bacterial drug therapy, Nitrates blood, Nitrates cerebrospinal fluid, Nitric Oxide biosynthesis, Nitrites blood, Nitrites cerebrospinal fluid, Tumor Necrosis Factor-alpha metabolism, Meningitis, Bacterial blood, Meningitis, Bacterial cerebrospinal fluid, Nitric Oxide blood, Nitric Oxide cerebrospinal fluid
- Abstract
To investigate the role of nitric oxide (NO) in bacterial meningitis, concentrations in serum, cerebrospinal fluid (CSF), or both of the precursor (L-arginine) and degradation products of NO (nitrate, nitrite) and tumor necrosis factor (TNF)-alpha were measured in 35 patients and 30 controls. CSF nitrate levels were significantly elevated, mainly due to increased blood-brain barrier permeability, and are therefore not a good parameter for gauging endogenous NO production in the CSF compartment. CSF NO/nitrite levels were significantly elevated in patients. NO/nitrite levels decreased over time (26%/6 h; P < .001). CSF levels of NO/nitrite correlated with those of TNF-alpha (r = .55; P = .001) and glucose (r = -.43; P = .02). CSF levels of L-arginine were lower in patients than in controls (P < .001). Dexamethasone did not exert a significant effect on NO metabolism. In conclusion, enhanced NO production may contribute to anaerobic glycolysis and neurologic damage in bacterial meningitis.
- Published
- 1996
- Full Text
- View/download PDF
36. Interleukin-10 and soluble tumor necrosis factor receptors in cerebrospinal fluid of children with bacterial meningitis.
- Author
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Kornelisse RF, Savelkoul HF, Mulder PH, Suur MH, van der Straaten PJ, van der Heijden AJ, Sukhai RN, Hählen K, Neijens HJ, and de Groot R
- Subjects
- Adolescent, Antigens, CD biosynthesis, Cefotaxime therapeutic use, Ceftazidime therapeutic use, Cephalosporins therapeutic use, Child, Child, Preschool, Cytokines blood, Cytokines cerebrospinal fluid, Female, Humans, Infant, Interleukin-10 biosynthesis, Interleukin-10 blood, Male, Meningitis, Bacterial drug therapy, Meningitis, Bacterial immunology, Receptors, Tumor Necrosis Factor biosynthesis, Receptors, Tumor Necrosis Factor, Type I, Receptors, Tumor Necrosis Factor, Type II, Tumor Necrosis Factor-alpha biosynthesis, Tumor Necrosis Factor-alpha cerebrospinal fluid, Antigens, CD analysis, Interleukin-10 cerebrospinal fluid, Meningitis, Bacterial cerebrospinal fluid, Receptors, Tumor Necrosis Factor analysis
- Abstract
The antiinflammatory mediators interleukin (IL)-10 and soluble tumor necrosis factor (TNF) receptors p55 (sTNFR-55) and sTNFR-75 in cerebrospinal fluid (CSF) from 37 children with bacterial meningitis were studied. CSF concentrations of IL-10, sTNFR-55, and sTNFR-75 and of the proinflammatory cytokines TNF-alpha, IL-6, and IL-8 were markedly elevated and were, with the exception of the sTNFRs, significantly higher in CSF than in serum. CSF concentrations of sTNFR- 55 and sTNFR-75 were only associated positively with IL-10 levels. CSF glucose levels correlated highly with levels of IL-10, sTNFR-55, and sTNFR-75 and weakly with TNF-alpha and IL-6. Cytokine levels in CSF decreased rapidly, while sTNFR levels remained elevated for at least 24 h.
- Published
- 1996
- Full Text
- View/download PDF
37. The relationship between plasminogen activator inhibitor-1 and proinflammatory and counterinflammatory mediators in children with meningococcal septic shock.
- Author
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Kornelisse RF, Hazelzet JA, Savelkoul HF, Hop WC, Suur MH, Borsboom AN, Risseeuw-Appel IM, van der Voort E, and de Groot R
- Subjects
- Adolescent, Antigens, CD analysis, Blood Coagulation, Child, Child, Preschool, Female, Fibrinolysis, Humans, Infant, Interleukin-10 blood, Interleukin-6 blood, Interleukin-8 blood, Male, Meningococcal Infections immunology, Prospective Studies, Purpura, Receptors, Tumor Necrosis Factor, Type I, Receptors, Tumor Necrosis Factor, Type II, Shock, Septic immunology, Tumor Necrosis Factor-alpha analysis, Cytokines blood, Meningococcal Infections blood, Plasminogen Activator Inhibitor 1 blood, Receptors, Tumor Necrosis Factor analysis, Shock, Septic blood
- Abstract
Proinflammatory cytokines (tumor necrosis factor [TNF]-alpha and interleukin [IL]-6 and -8), counterinflammatory compounds (IL-10 and soluble TNF receptors p55 and p75 [sTNFR-55 and -75]), and hemostatic parameters were determined in 38 patients with meningococcal septic shock. Eleven patients (29%) died. Serum levels of pro- and counterinflammatory compounds and plasma levels of plasminogen activator inhibitor (PAI)-1 were significantly higher in nonsurvivors. The interval between appearance of petechiae and blood sampling was shorter in nonsurvivors than in survivors (3.6 +/- 2.4 vs. 6.1 +/- 3.3 h; P = 0.4). This interval correlated strongly with the levels of TNF-alpha, IL-6, -8, and -10, sTNFR-55 and -75, and PAI-1. However, with the exception of PAI-1, differences between concentrations of these mediators disappeared after adjustment for the interval. PAI-1 levels correlated with TNF-alpha concentrations (r = .75; P < .001) and were 1.9 (P = .01) times higher in nonsurvivors at a similar TNF-alpha concentration. Thus, an increased PAI-1 response to TNF-alpha may be associated with fatality, probably because of polymorphism of the PAI-1 gene.
- Published
- 1996
- Full Text
- View/download PDF
38. Risk of dementia in patients with Parkinson's disease, epilepsy, and severe head trauma: a register-based follow-up study.
- Author
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Breteler MM, de Groot RR, van Romunde LK, and Hofman A
- Subjects
- Age Distribution, Aged, Cohort Studies, Craniocerebral Trauma complications, Dementia etiology, Epilepsy complications, Female, Follow-Up Studies, Humans, Incidence, Male, Middle Aged, Netherlands epidemiology, Parkinson Disease complications, Risk Factors, Sex Distribution, Time Factors, Craniocerebral Trauma epidemiology, Dementia epidemiology, Epilepsy epidemiology, Parkinson Disease epidemiology, Registries statistics & numerical data
- Abstract
The authors investigated the risk of developing dementia for persons aged 50-75 years who suffered from Parkinson's disease, epilepsy, or severe head trauma. They compared the risk in this patient group with the risk in a reference group in a follow-up study based on the linked databases of three Dutch nationwide morbidity registers over the years 1980-1989. The overall relative risk of developing dementia within 8 years in patients with Parkinson's disease who were initially free of dementia was 3.0 (95% confidence interval (CI) 2.9-3.1). Risk was especially increased in younger Parkinson's disease patients (relative risk (RR) = 13.2, 95% CI 6.2-28.6). For patients with epilepsy, the overall relative risk was 1.5 (95% CI 1.4-1.7). Severe head trauma was not associated with an increased risk of dementia (RR = 1.0, 95% CI 0.9-1.1). These findings suggest that Parkinson's disease is an important risk factor for dementia, with a particularly high risk in young patients with Parkinson's disease. Patients with epilepsy may bear a moderately increased risk of developing dementia. This study does not support earlier findings in retrospective case-control studies of an increased risk of dementia in head trauma patients.
- Published
- 1995
- Full Text
- View/download PDF
39. Pneumococcal meningitis in children: prognostic indicators and outcome.
- Author
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Kornelisse RF, Westerbeek CM, Spoor AB, van der Heijde B, Spanjaard L, Neijens HJ, and de Groot R
- Subjects
- Age Factors, Causality, Child, Child, Preschool, Female, Humans, Infant, Infant, Newborn, Male, Meningitis, Pneumococcal cerebrospinal fluid, Meningitis, Pneumococcal mortality, Meningitis, Pneumococcal therapy, Neurologic Examination, Prognosis, Serotyping, Streptococcus pneumoniae classification, Streptococcus pneumoniae isolation & purification, Survival Analysis, Meningitis, Pneumococcal physiopathology
- Abstract
We studied the outcome of pneumococcal meningitis in 83 children who were admitted to a referral hospital and whose meningitis was diagnosed between 1970 and 1994. The median age of the children was 8 months. The most frequently isolated capsular serotypes and/or serogroups of Streptococcus pneumoniae were 6, 14, 18, 19, and 23. Twenty-nine children (35%) were referred by other hospitals. A mortality rate of 17% (primary referrals, 7%; secondary referrals, 35%) was observed. At discharge, 25 survivors (36%) had sequelae: hearing loss (> or = 30 dB) in 19% and neurological sequelae in 25%. During admission, the presence of coma, respiratory distress, shock, a cerebrospinal fluid (CSF) protein level of > or = 2.5 g/L, a peripheral white blood cell count of < 5 x 10(9)/L, and a serum sodium level of < 135 mmol/L were associated with mortality. Sequelae were associated with the presence of coma and a CSF glucose level of < 0.6 mmol/L. We conclude that the mortality rate of pneumococcal meningitis is lower among children than among adults. Children often die of neurological sequelae, while adults frequently die of cardiorespiratory failure due to underlying diseases. For children, coma, respiratory distress, and shock during admission were the clinical findings with the strongest predictive value for sequelae or death.
- Published
- 1995
- Full Text
- View/download PDF
40. Homologous RNA recombination allows efficient introduction of site-specific mutations into the genome of coronavirus MHV-A59 via synthetic co-replicating RNAs.
- Author
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van der Most RG, Heijnen L, Spaan WJ, and de Groot RJ
- Subjects
- Base Sequence, Cell Line, Genome, Viral, Molecular Sequence Data, Oligoribonucleotides genetics, Polymerase Chain Reaction, Sequence Homology, Nucleic Acid, Coronaviridae genetics, Defective Viruses genetics, Mutagenesis, Site-Directed genetics, RNA, Viral genetics, Recombination, Genetic genetics
- Abstract
We describe a novel strategy to site-specifically mutagenize the genome of an RNA virus by exploiting homologous RNA recombination between synthetic defective interfering (DI) RNA and the viral RNA. The construction of a full-length cDNA clone, pMIDI, of a DI RNA of coronavirus MHV strain A59 was reported previously (R.G. Van der Most, P.J. Bredenbeek, and W.J.M. Spaan (1991). J. Virol. 65, 3219-3226). RNA transcribed from this construct, is replicated efficiently in MHV-infected cells. Marker mutations introduced in MIDI RNA were replaced by the wild-type residues during replication. More importantly, however, these genetic markers were introduced into viral genome: even in the absence of positive selection MHV recombinants could be isolated. This finding provides new prospects for the study of coronavirus replication using recombinant DNA techniques. As a first application, we describe the rescue of the temperature sensitive mutant MHV Albany-4 using DI-directed mutagenesis. Possibilities and limitations of this strategy are discussed.
- Published
- 1992
- Full Text
- View/download PDF
41. EGF-induced jun B-expression in transfected P19 embryonal carcinoma cells expressing EGF-receptors is dependent on Jun D.
- Author
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den Hertog J, de Groot RP, de Laat SW, and Kruijer W
- Subjects
- Blotting, Northern, Calcimycin pharmacology, Chloramphenicol O-Acetyltransferase genetics, Chloramphenicol O-Acetyltransferase metabolism, Drug Synergism, Embryonal Carcinoma Stem Cells, ErbB Receptors genetics, Neoplastic Stem Cells, Promoter Regions, Genetic genetics, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Repetitive Sequences, Nucleic Acid genetics, Tetradecanoylphorbol Acetate pharmacology, Transcriptional Activation genetics, Transfection, Tumor Cells, Cultured, Epidermal Growth Factor pharmacology, Gene Expression Regulation drug effects, Genes, jun, Proto-Oncogene Proteins genetics, Proto-Oncogene Proteins c-jun genetics
- Abstract
The TPA-inducible transcription factor AP-1, consisting of homo- or hetero-dimers of members of the Jun- and Fos-families, regulates transcription of a wide variety of genes containing the TPA response element (TRE). In P19 embryonal carcinoma (EC) cells, Jun D is the only component of AP-1 expressed, while in these cells until now none of the members of the jun- and fos-families have been found to be inducable by external stimuli. Here we demonstrate that Jun B is the only member of the Jun- and Fos-families that is induced by Epidermal Growth Factor (EGF) in transfected murine P19 EC cells, expressing functional human EGF receptors (hEGF-Rs). Induction of jun B can be mimicked in wild type P19 EC cells by the synergistic action of the phorbol ester TPA and the calcium ionophore A23187, through activation of signal transduction pathways, that are activated simultaneously by EGF. The EGF induced jun B expression in the hEGF-R expressing P19 EC cells is mediated by an inverted repeat (IR) sequence in the jun B promoter, previously shown to be responsive to both PKC and PKA signal transduction. Transactivation of the IR sequence by EGF can be blocked completely by prior expression of antisense Jun D, but not by antisense c-Jun. These studies therefore implicate Jun D in the regulation of immediate early gene expression by external stimuli.
- Published
- 1992
- Full Text
- View/download PDF
42. Transcriptional control of c-jun by retinoic acid.
- Author
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de Groot RP, Pals C, and Kruijer W
- Subjects
- Animals, Base Sequence, Carrier Proteins genetics, Carrier Proteins metabolism, Chloramphenicol O-Acetyltransferase genetics, Cloning, Molecular, DNA Fingerprinting, Mice, Mice, Inbred BALB C, Molecular Sequence Data, Plasmids, Promoter Regions, Genetic, Proto-Oncogene Proteins c-jun, Receptors, Retinoic Acid, Transcriptional Activation, DNA-Binding Proteins genetics, Proto-Oncogene Proteins genetics, Transcription Factors genetics, Transcription, Genetic drug effects, Tretinoin pharmacology
- Abstract
The proto-oncogene c-jun, a major component of transcription factor AP-1, is expressed at very low levels in undifferentiated embryonal carcinoma (EC) end embryonic stem (ES) cells. Retinoic acid (RA) induced differentiation causes a strong increase in the levels of c-jun mRNA. In this paper we report the cloning and characterization of the mouse c-jun promoter. Our results show that RA treatment causes a strong enhancement in c-jun promoter activity, an effect probably mediated by the RA-receptor beta (RAR beta). Sequences located between -329 and -293 are responsible for the observed RA effect, and bind at least five different protein complexes, of which three are decreased upon RA treatment. These protein binding sites do not resemble RA-responsive elements (RARE's) found in the promoters of retinoic acid receptor beta (RAR beta) and laminin B1. Furthermore, we could not detect a direct interaction of RAR alpha and RAR beta to these sequences, indicating that RA-induced c-jun expression is an indirect effect of RAR action.
- Published
- 1991
- Full Text
- View/download PDF
43. Activation of junB by PKC and PKA signal transduction through a novel cis-acting element.
- Author
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de Groot RP, Auwerx J, Karperien M, Staels B, and Kruijer W
- Subjects
- Animals, Base Sequence, Blood, Blotting, Northern, Cross-Linking Reagents, Mice, Molecular Sequence Data, Plasmids, Promoter Regions, Genetic, Proto-Oncogene Proteins c-jun, RNA analysis, Transfection, Tumor Cells, Cultured, DNA-Binding Proteins genetics, Protein Kinase C metabolism, Protein Kinases metabolism, Signal Transduction, Transcription Factors genetics
- Abstract
The product of the junB gene, a gene homologous to the proto-oncogene c-jun, is a component of transcription factor AP-1. JunB expression is modulated by a wide variety of extracellular stimuli, such as serum, growth factors, phorbol esters (TPA) and activators of protein kinase A (PKA). In order to study the molecular basis of this complex regulation, we have cloned the mouse junB gene from a genomic testis library, and characterized the junB promoter. Here we show that the junB promoter is activated by serum, TPA, and activated PKA. Sequences located between -91 and -44 are necessary for induction. These sequences contain a CAAT box, a G-C rich region and a previously undescribed inverted repeat (IR). The IR element can mediate induction by TPA and PKA when coupled to a heterologous promoter, and specifically binds a protein of 110 kD.
- Published
- 1991
- Full Text
- View/download PDF
44. Differential expression of jun and fos genes during differentiation of mouse P19 embryonal carcinoma cells.
- Author
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de Groot RP, Schoorlemmer J, van Genesen ST, and Kruijer W
- Subjects
- Animals, Blotting, Northern, Cell Differentiation, Embryonal Carcinoma Stem Cells, Mice, Neoplastic Stem Cells metabolism, Plasmids, Proto-Oncogene Proteins c-fos, Proto-Oncogene Proteins c-jun, Tetradecanoylphorbol Acetate pharmacology, Transcription, Genetic, Tretinoin pharmacology, DNA-Binding Proteins genetics, Gene Expression Regulation, Neoplastic, Neoplastic Stem Cells cytology, Proto-Oncogene Proteins genetics, Proto-Oncogenes, Transcription Factors genetics
- Abstract
The jun and fos gene families encode DNA binding proteins involved in transcriptional regulation of genes containing a TPA responsive element (TRE). To study their role in gene regulation during early mammalian development, expression and transcription regulatory properties of their gene products were investigated during retinoic acid (RA) induced differentiation of P19 embryonal carcinoma (EC) cells. Our results show, that c-jun is expressed at low but detectable levels in undifferentiated P19 EC cells and at elevated levels in its RA differentiated derivatives, corresponding with increased expression of Jun and TRE binding activity. Jun D is constitutively expressed at constant levels in both undifferentiated and differentiated P19 cells, while jun B and c-fos are not expressed. Addition of TPA to undifferentiated P19 cells does not result in induction of c-jun, jun B and c-fos, while these genes are transiently induced in RA-differentiated P19 cells. In addition, TPA treatment resulted in expression of Fos and Jun protein in RA-differentiated, but not in undifferentiated P19 cells. Addition of TPA to P19 EC cells expressing low levels of TRE binding proteins is neither followed by transcriptional activation of the TRE reporter gene nor by induction of c-jun, previously shown to be autoregulated by its own gene product. By contrast, in P19 cells differentiated by RA that contain elevated levels of TRE binding proteins, TRE dependent transcription is enhanced upon TPA treatment.
- Published
- 1990
- Full Text
- View/download PDF
45. Coding sequence of a ferredoxin gene from Anabaena variabilis ATCC 29413.
- Author
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van der Plas J, de Groot RP, Weisbeek PJ, and van Arkel GA
- Subjects
- Amino Acid Sequence, Base Sequence, Cyanobacteria genetics, Ferredoxins genetics
- Published
- 1986
- Full Text
- View/download PDF
46. Coding sequence of a ferredoxin gene from Anacystis nidulans R2 (Synechococcus PCC7942).
- Author
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van der Plas J, de Groot RP, Woortman MR, Weisbeek PJ, and van Arkel GA
- Subjects
- Base Sequence, Cyanobacteria genetics, Ferredoxins genetics
- Published
- 1986
- Full Text
- View/download PDF
47. Use of a radon mould technique for skin cancer: results from the Peter MacCallum Cancer Institute (1975-1984).
- Author
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Ashby MA, Pacella JA, de Groot R, and Ainslie J
- Subjects
- Adult, Aged, Aged, 80 and over, Carcinoma, Basal Cell radiotherapy, Carcinoma, Squamous Cell radiotherapy, Female, Humans, Male, Middle Aged, Brachytherapy methods, Radon therapeutic use, Skin Neoplasms radiotherapy
- Abstract
During the period from 1975 to 1984, 642 patients had non-melanoma skin cancers (NMSC) treated by a radon mould technique following the principles of the Manchester system. The results of 77 out of 642 (12%) with histologically verified lesions are presented. The sites of the lesions were as follows: head and neck 25 (32%), upper limbs 38 (49%), lower limbs 13 (17%) and trunk one case only. The histological diagnosis was squamous cell carcinoma 48 (62%), basal cell carcinoma in 22 (29%) and other in seven (9%). There were nine out of 77 (12%) failures, four with persistent disease, which did not clear after initial treatment (and for whom the radon mould was an inappropriate choice of technique), and five (6%) recurrences after clearance of the initial lesion. There was a sharp rise in failures after 1979 when there was a change of radon supplier, but no calibration error was substantiated. It is clearly beneficial for institutions to cross-check the manufacturer's brachytherapy source data. There have been no further recurrences or any symptomatic late morbidity. This is a safe, effective and practical radiotherapeutic technique for superficial lesions (not exceeding a depth of 4 mm) in areas of poor radiation tolerance, and may obviate the need for a prolonged fractionated course of external-beam radiation in selected patients. Alternatives to radon are discussed.
- Published
- 1989
- Full Text
- View/download PDF
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