90 results on '"Gillissen F"'
Search Results
2. Sustainability of an Enhanced Recovery After Surgery Program (ERAS) in Colonic Surgery
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Gillissen, F., Ament, S. M. C., Maessen, J. M. C., Dejong, C. H. C., Dirksen, C. D., van der Weijden, T., and von Meyenfeldt, M. F.
- Published
- 2015
- Full Text
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3. Effects of flow regime and flooding on heavy metal availability in sediment and soil of a dynamic river system
- Author
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Poot, A., Gillissen, F., and Koelmans, A.A.
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- 2007
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- View/download PDF
4. Temporal dynamics of AVS and SEM in sediment of shallow freshwater floodplain lakes
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van Griethuysen, C., de Lange, H.J., van den Heuij, M., de Bies, S.C., Gillissen, F., and Koelmans, A.A.
- Published
- 2006
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5. Measuring acid volatile sulphide in floodplain lake sediments: effect of reaction time, sample size and aeration
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van Griethuysen, C, Gillissen, F, and Koelmans, A.A
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- 2002
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6. Data from: Horizontal and vertical diversity jointly shape food web stability against small and large perturbations
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Zhao, Qinghua, van den Brink, P.J., Carpentier, Camille, Wang, Yingying, Rodríguez Sánchez, P., Xu, Chi, Vollbrecht, Silke, Gillissen, F., Vollebregt, M.E., Wang, Shaopeng, De Laender, Frederik, Zhao, Qinghua, van den Brink, P.J., Carpentier, Camille, Wang, Yingying, Rodríguez Sánchez, P., Xu, Chi, Vollbrecht, Silke, Gillissen, F., Vollebregt, M.E., Wang, Shaopeng, and De Laender, Frederik
- Abstract
The biodiversity of food webs is composed of horizontal (i.e. within trophic levels) and vertical diversity (i.e. the number of trophic levels). Understanding their joint effect on stability is a key challenge. Theory mostly considers their individual effects and focuses on small perturbations near equilibrium in hypothetical food webs. Here, we study the joint effects of horizontal and vertical diversity on the stability of hypothetical (modelled) and empirical food webs. In modelled food webs, horizontal and vertical diversity increased and decreased stability, respectively, with a stronger positive effect of producer diversity on stability at higher consumer diversity. Experiments with an empirical plankton food-web, where we manipulated horizontal and vertical diversity and measured stability from species interactions and from resilience against large perturbations, confirmed these predictions. Taken together, our findings highlight the need to conserve horizontal biodiversity at different trophic levels to ensure stability.
- Published
- 2019
7. [Cognitive disorders appearing before the age of 65 in patients of the Alzheimer Centre of the VU Medical Centre: diagnoses and clinical characteristics]
- Author
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Pijnenburg, Y.A.L., Zeeman-Rebel, A., van der Flier, W.M., Romkes, R.M., Gillissen, F., Jonker, C., Scheltens, P., and Sociology and Social Gerontology
- Published
- 2005
8. Nalevering van zware metalen en organische microverontreinigingen uit waterbodems: metingen stikstof, organisch koolstof en black carbon
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Koelmans, A.A. and Gillissen, F.
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Aquatic Ecology and Water Quality Management ,WIMEK ,Life Science ,Aquatische Ecologie en Waterkwaliteitsbeheer ,Wageningen Marine Research - Published
- 2008
9. Schatting van in situ fluxen van organische microverontreinigingen uit waterbodems
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Koelmans, A.A., Poot, A., and Gillissen, F.
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Aquatic Ecology and Water Quality Management ,water pollution ,WIMEK ,water bottoms ,organic pollutants ,organische verontreinigende stoffen ,ecotoxicologie ,Aquatische Ecologie en Waterkwaliteitsbeheer ,oppervlaktewaterkwaliteit ,Wageningen Marine Research ,ecotoxicology ,pollutants ,sediment ,waterverontreiniging ,biologische beschikbaarheid ,bioavailability ,waterbodems ,surface water quality ,verontreinigende stoffen - Abstract
Dit rapport beschrijft de resultaten van een onderzoek naar naleveringsfluxen van organische microverontreinigingen, ten behoeve van het Deltares koploperproject “Biobeschikbaarheid en gedrag van stoffen”, deelproject A “Nalevering van stoffen uit waterbodems”. Hierin wordt het belang van nalevering voor de kwaliteit van het oppervlaktewater onderzocht. Dit project moet leiden tot inzicht in de situaties waarin nalevering van stoffen uit de waterbodem naar het oppervlaktewater een significante (secundaire) verontreinigingbron vormt. Dit met het oog op normoverschrijding in het oppervlaktewater (chemische doelstelling KRW), of het niet bereiken van een goede ecologische toestand (ecologische doelstelling KRW). In het voorliggende rapport worden de resultaten van kolom flux-experimenten besproken. Aan de orde komen: (a) opzet meetprogramma voor zover afwijkend van het meetplan, (b) informatie met betrekking tot kwaliteitscontrole, (c) specificatie van gebruikte analysevoorschriften (d) analyseresultaten met korte toelichting
- Published
- 2008
10. Cognitieve stoornissen optredend vóór de leeftijd van 65 jaar bij patiënten van het Alzheimercentrum van het VU Medisch Centrum:Diagnosen en klinische kenmerken
- Author
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Pijnenburg, Y. A.L., Zeeman-Rebel, A., Van Der Flier, W. M., Romkes, R. M., Gillissen, F., Jonker, C., and Scheltens, Ph
- Subjects
mental disorders - Abstract
Objective. To obtain a profile of the causes and clinical characteristics of cognitive disorders in patients referred to a memory clinic before the age of 65 years. Design. Retrospective case-note study. Method. Data were collected from 127 subjects with objective cognitive disorders who visited the Alzheimer Centre of the VU Medical Centre in Amsterdam, the Netherlands, in the period from 1 January 2001 to 31 December 2003 with an onset of complaints before the age of 65. Besides the diagnoses, we investigated the clinical presentations, the occurrence of cardiovascular risk factors, the family history, and the presence of non-cognitive neurological signs. Results. The most common causes of cognitive decline under the age of 65 were Alzheimer's disease (46%) and frontotemporal dementia (23%). Vascular dementia was seen in 5% and dementia with Lewy bodies in 2%; 9% had mild cognitive impairment but no dementia. Hypertension and a positive family history for dementia were each present in 40% of the patients. Non-cognitive neurological abnormalities were found only in cases of non-Alzheimer dementia. During the period under investigation, the number of patients with objective cognitive disorders increased more than did the number without a cognitive disorder. Conclusion. Within the population of a memory clinic, Alzheimer's disease was the most frequent cause of cognitive decline under the age of 65, followed by frontotemporal dementia. The distribution differed from causes of dementia at an older age, where vascular dementia had the second place.
- Published
- 2005
11. Cognitieve stoornissen optredend voor de leeftijd van 65 jaar bij patienten van het Alzheimercentrum van het VU medisch centrum: diagnosen en klinische kenmerken
- Author
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Pijnenburg, Y. A.L., Zeeman-Rebel, A., Van Der Flier, W. M., Romkes, R. M., Gillissen, F., Jonker, C., Scheltens, Ph, Sociology and Social Gerontology, EMGO+ - Mental Health, Neurology, Epidemiology and Data Science, Amsterdam Neuroscience - Neurodegeneration, and Psychiatry
- Subjects
mental disorders - Abstract
Objective. To obtain a profile of the causes and clinical characteristics of cognitive disorders in patients referred to a memory clinic before the age of 65 years. Design. Retrospective case-note study. Method. Data were collected from 127 subjects with objective cognitive disorders who visited the Alzheimer Centre of the VU Medical Centre in Amsterdam, the Netherlands, in the period from 1 January 2001 to 31 December 2003 with an onset of complaints before the age of 65. Besides the diagnoses, we investigated the clinical presentations, the occurrence of cardiovascular risk factors, the family history, and the presence of non-cognitive neurological signs. Results. The most common causes of cognitive decline under the age of 65 were Alzheimer's disease (46%) and frontotemporal dementia (23%). Vascular dementia was seen in 5% and dementia with Lewy bodies in 2%; 9% had mild cognitive impairment but no dementia. Hypertension and a positive family history for dementia were each present in 40% of the patients. Non-cognitive neurological abnormalities were found only in cases of non-Alzheimer dementia. During the period under investigation, the number of patients with objective cognitive disorders increased more than did the number without a cognitive disorder. Conclusion. Within the population of a memory clinic, Alzheimer's disease was the most frequent cause of cognitive decline under the age of 65, followed by frontotemporal dementia. The distribution differed from causes of dementia at an older age, where vascular dementia had the second place.
- Published
- 2005
12. Towards a Framework for Analysing Sustainability of Economic Value: The Case of a Short Stay Programme for Breast Cancer Surgery Care Five Years After Implementation
- Author
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Ament, S., primary, Gillissen, F., additional, Maessen, J., additional, van der Weijden, T., additional, von Meyenfeldt, M., additional, and Dirksen, C.D., additional
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- 2014
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13. Sustainability of an Enhanced Recovery After Surgery Program (ERAS) in Colonic Surgery
- Author
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Gillissen, F., primary, Ament, S. M. C., additional, Maessen, J. M. C., additional, Dejong, C. H. C., additional, Dirksen, C. D., additional, van der Weijden, T., additional, and von Meyenfeldt, M. F., additional
- Published
- 2014
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14. A comparative study on three analytical methods for the determination of the neurotoxin BMAA in cyanobacteria
- Author
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Faassen, E.J., Gillissen, F., Lurling, M., Faassen, E.J., Gillissen, F., and Lurling, M.
- Abstract
The cyanobacterial neurotoxin ß-N-methylamino-L-alanine (BMAA) has been considered a serious health threat because of its putative role in multiple neurodegenerative diseases. First reports on BMAA concentrations in cyanobacteria were alarming: nearly all cyanobacteria were assumed to contain high BMAA concentrations, implying ubiquitous exposure. Recent studies however question this presence of high BMAA concentrations in cyanobacteria. To assess the real risk of BMAA to human health, this discrepancy must be resolved. We therefore tested whether the differences found could be caused by the analytical methods used in different studies. Eight cyanobacterial samples and two control samples were analyzed by three commonly used methods: HPLC-FLD analysis and LC-MS/MS analysis of both derivatized and underivatized samples. In line with published results, HPLC-FLD detected relatively high BMAA concentrations in some cyanobacterial samples, while both LC-MS/MS methods only detected BMAA in the positive control (cycad seed sarcotesta). Because we could eliminate the use of different samples and treatments as causal factors, we demonstrate that the observed differences were caused by the analytical methods. We conclude that HPLC-FLD overestimated BMAA concentrations in some cyanobacterial samples due to its low selectivity and propose that BMAA might be present in (some) cyanobacteria, but in the low µg/g or ng/g range instead of the high µg/g range as sometimes reported before. We therefore recommend to use only selective and sensitive analytical methods like LC-MS/MS for BMAA analysis. Although possibly present in low concentrations in cyanobacteria, BMAA can still form a health risk. Recent evidence on BMAA accumulation in aquatic food chains suggests human exposure through consumption of fish and shellfish which expectedly exceeds exposure through cyanobacteria The cyanobacterial neurotoxin ß-N-methylamino-L-alanine (BMAA) has been considered a serious health threat bec
- Published
- 2012
15. (Cost)-effectiveness of family meetings on indicated prevention of anxiety and depressive symptoms and disorders of primary family caregivers of patients with dementia: design of a randomized controlled trial.
- Author
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Joling, K.J., Hout, H.P.J. van, Scheltens, P., Vernooy-Dassen, M.J.F.J., Berg, B. van den, Bosmans, J., Gillissen, F., Mittelman, M., Marwijk, H.W.J. van, Joling, K.J., Hout, H.P.J. van, Scheltens, P., Vernooy-Dassen, M.J.F.J., Berg, B. van den, Bosmans, J., Gillissen, F., Mittelman, M., and Marwijk, H.W.J. van
- Abstract
Contains fulltext : 70773.pdf (publisher's version ) (Open Access), BACKGROUND: Dementia is a major public health problem with enormous costs to society and major consequences for both patients and their relatives. Family members of persons with dementia provide much of the care for older adults with dementia in the community. Caring for a demented relative is not easy and fraught with emotional strain, distress, and physical exhaustion. Family caregivers of dementia patients have an extremely high risk developing affective disorders such as major depression and anxiety disorder. Family meetings appear to be among the most powerful psychosocial interventions to reduce depression in caregivers.An American landmark study reported substantial beneficial effects of a multifaceted intervention where family meetings had a central place on depression in family caregivers as well as on delay of institutionalization of patients. These effects were not replicated in other countries yet. We perform the first trial comparing only structured family meetings with significant others versus usual care among primary family caregivers of community dwelling demented patients and measure the effectiveness on both depression and anxiety in the primary caregiver, both on disorder and symptom levels. METHODS/DESIGN: In this randomized controlled trial effectiveness as well as cost-effectiveness of family meetings is evaluated. The intervention group receives four family meetings with family and close friends of the primary family caregiver of a community dwelling patient with a clinical diagnosis of dementia. Dyads of patients and their primary caregiver are followed up to one year after baseline assessment. The main outcome measures are the incidence of anxiety and depressive disorders assessed with the Mini-International Neuropsychiatric Interview (MINI) and the severity of anxiety and depressive symptoms in caregivers is measured by validated self report instruments: the Centre for Epidemiologic Studies Depression Scale (CES-D) for depression and the a
- Published
- 2008
16. Impact of diagnostic disclosure in dementia on patients and carers: qualitative case series analysis.
- Author
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Derksen, E., Vernooy-Dassen, M.J.F.J., Gillissen, F., Olde Rikkert, M.G.M., Scheltens, P., Derksen, E., Vernooy-Dassen, M.J.F.J., Gillissen, F., Olde Rikkert, M.G.M., and Scheltens, P.
- Abstract
Contains fulltext : 51315.pdf (publisher's version ) (Closed access), Adequate diagnostic information can be considered a basic intervention in dementia care. However, clear diagnostic disclosure in dementia is not yet regular practice and the evidence regarding patients' preferences for or against disclosure is scarce. The aim of this study was to give an in-depth description of the impact of receiving the diagnosis of dementia, both on patients and the patients' proxies. The method used was the design of a grounded theory interview study. Analysis of the interviews revealed that disclosure had an impact on three key domains: awareness of dementia, partnership, and social relationships. Most patients and carers reported that they had experienced the disclosure of the diagnosis as a confirmation of their assumptions. A minority of patients and carers felt threatened and shocked by the diagnosis, because they did not expect it. The findings of this analysis challenge current opinions and practice about diagnostic disclosure like obstacles anticipated by clinicians such as inducing negative feelings and causing harm. Disclosure of the diagnosis of dementia can generally be carried out without introducing stress for the patient or carer and facilitates guidance. Therefore regular practice should include the careful planning and performance of diagnostic disclosure.
- Published
- 2006
17. The impact of diagnostic disclosure in dementia: a qualitative case analysis.
- Author
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Derksen, E.W.C., Vernooy-Dassen, M.J.F.J., Gillissen, F., Olde Rikkert, M.G.M., Scheltens, P., Derksen, E.W.C., Vernooy-Dassen, M.J.F.J., Gillissen, F., Olde Rikkert, M.G.M., and Scheltens, P.
- Abstract
Contains fulltext : 48398.pdf (publisher's version ) (Closed access), OBJECTIVE: The aim of this study was to give an in-depth description of the impact of disclosure of the diagnosis of dementia on a patient and the patient's partner. METHODS: Grounded theory interview study. RESULTS: Analysis of the interviews revealed that disclosure had an impact on three key domains: awareness of dementia, interpersonal relationship and social relationships. Disclosure was perceived as a confirmation of the pre-test ideas of both patient and carer. Formal disclosure of dementia was especially relevant for the carer in reconsidering her response to the patient's changed behavior. DISCUSSION: Receiving the diagnosis of dementia can be considered as a crucial moment in the process of becoming aware of the changes in one's life. Moreover, disclosure marks a new phase in the process of caring by the caregiver.
- Published
- 2005
18. Geochemisch onderzoek naar het gedrag van enkele zware metalen in het Volkerak/Zoommeer. Herziene versie
- Author
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Koelmans, A.A., Radovanovic, H., and Gillissen, F.
- Subjects
Aquatic Ecology and Water Quality Management ,WIMEK ,Life Science ,Aquatische Ecologie en Waterkwaliteitsbeheer - Published
- 1994
19. Impact of diagnostic disclosure in dementia on patients and carers: Qualitative case series analysis
- Author
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Derksen, E., primary, Vernooij-Dassen, M., additional, Gillissen, F., additional, Olde Rikkert, M., additional, and Scheltens, P., additional
- Published
- 2006
- Full Text
- View/download PDF
20. PCN275 - Towards a Framework for Analysing Sustainability of Economic Value: The Case of a Short Stay Programme for Breast Cancer Surgery Care Five Years After Implementation
- Author
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Ament, S., Gillissen, F., Maessen, J., van der Weijden, T., von Meyenfeldt, M., and Dirksen, C.D.
- Published
- 2014
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21. Influence of salinity and mineralization on trace metal sorption to cyanobacteria in natural waters
- Author
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Koelmans, A.A., primary, Gillissen, F., additional, and Lijklema, L., additional
- Published
- 1996
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22. Apolipoprotein E genotype influences presence and severity of delusions and aggressive behavior in Alzheimer Disease.
- Author
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van der Flier WM, Staekenborg S, Pijnenburg YAL, Gillissen F, Romkes R, Kok A, Bouwman FH, and Scheltens P
- Abstract
Aim: We investigated differences in the prevalence and severity of 10 neuropsychiatric and behavioral symptoms according to apolipoprotein E (APOE) genotype and dementia severity in Alzheimer disease (AD). Methods: Neuropsychiatric and behavioral symptoms of 110 AD patients were assessed using the Neuropsychatric Inventory. Dementia severity was assessed using the Mini Mental State Examination (MMSE). Results: There were 27 APOE-4-negative patients, 65 heterozygous patients and 18 homozygous patients. There was a significant association between the number of APOE 4 alleles and prevalence and severity of neuropsychiatric and behavioral symptoms that was mainly attributable to delusions and agitation/aggression, which were more common and severer among homozygous APOE 4 carriers. In addition, the presence of hallucinations, anxiety, apathy and aberrant motor behavior increased with deteriorating MMSE score, independently of APOE 4 status. Conclusions: The present study showed that the APOE 4 genotype modifies neuropsychiatric and behavioral phenotype in AD. In particular, it was shown that delusions and agitation/aggression were more common and severer among homozygous APOE 4 carriers than among heterozygous or APOE-4-negative patients. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]
- Published
- 2006
23. The impact of diagnostic disclosure in dementia: a qualitative case analysis.
- Author
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Derksen E, Vernooij-Dassen M, Gillissen F, Olde-Rikkert M, Scheltens P, Derksen, Els, Vernooij-Dassen, Myrra, Gillissen, Freek, Olde-Rikkert, Marcel, and Scheltens, Philip
- Abstract
Objective: The aim of this study was to give an in-depth description of the impact of disclosure of the diagnosis of dementia on a patient and the patient's partner.Methods: Grounded theory interview study.Results: Analysis of the interviews revealed that disclosure had an impact on three key domains: awareness of dementia, interpersonal relationship and social relationships. Disclosure was perceived as a confirmation of the pre-test ideas of both patient and carer. Formal disclosure of dementia was especially relevant for the carer in reconsidering her response to the patient's changed behavior.Discussion: Receiving the diagnosis of dementia can be considered as a crucial moment in the process of becoming aware of the changes in one's life. Moreover, disclosure marks a new phase in the process of caring by the caregiver. [ABSTRACT FROM AUTHOR]- Published
- 2005
- Full Text
- View/download PDF
24. Doctor, is my mother suffering from dementia?,Dokter, heeft mijn moeder dementie?
- Author
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Philip Scheltens, Gillissen, F., Bouwman, F. H., and Flier, W. M.
25. Sustainability of healthcare innovations (SUSHI): long term effects of two implemented surgical care programmes (protocol)
- Author
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Ament Stephanie M C, Gillissen Freek, Maessen José M C, Dirksen Carmen D, van der Weijden Trudy, and von Meyenfeldt Maarten F
- Subjects
Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Two healthcare innovations were successfully implemented using different implementation strategies. First, a Short Stay Programme for breast cancer surgery (MaDO) was implemented in four early adopter hospitals, using a hospital-tailored implementation strategy. Second, the Enhanced Recovery After Surgery (ERAS) programme for colonic surgery was implemented in 33 Dutch hospitals, using a generic breakthrough implementation strategy. Both strategies resulted in a shorter hospital length of stay without a decrease in quality of care. Currently, it is unclear to what extent these innovative programmes and their results have been sustained three to five years following implementation. The aim of the sustainability of healthcare innovations (SUSHI) study is to analyse sustainability and its determinants using two implementation cases. Methods This observational study uses a mixed methods approach. The study will be performed in 14 hospitals in the Netherlands, from November 2010. For both implementation cases, the programme aspects and the effects will be evaluated by means of a follow-up measurement in 160 patients who underwent breast cancer surgery and 300 patients who underwent colonic surgery. A policy cost-effectiveness analysis from a societal perspective will be performed prospectively for the Short Stay Programme for breast cancer surgery in 160 patients. To study determinants of sustainability key professionals in the multidisciplinary care processes and implementation change agents will be interviewed using semi-structured interviews. Discussion The concept of sustainability is not commonly studied in implementation science. The SUSHI study will provide insight in to what extent the short-term implementation benefits have been maintained and in the determinants of long-term continuation of programme activities.
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- 2012
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26. (Cost)-effectiveness of family meetings on indicated prevention of anxiety and depressive symptoms and disorders of primary family caregivers of patients with dementia: design of a randomized controlled trial
- Author
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Gillissen Freek, Bosmans Judith, Vernooij-Dassen Myrra, van den Berg Bernard, Scheltens Philip, van Hout Hein PJ, Joling Karlijn J, Mittelman Mary, and van Marwijk Harm WJ
- Subjects
Geriatrics ,RC952-954.6 - Abstract
Abstract Background Dementia is a major public health problem with enormous costs to society and major consequences for both patients and their relatives. Family members of persons with dementia provide much of the care for older adults with dementia in the community. Caring for a demented relative is not easy and fraught with emotional strain, distress, and physical exhaustion. Family caregivers of dementia patients have an extremely high risk developing affective disorders such as major depression and anxiety disorder. Family meetings appear to be among the most powerful psychosocial interventions to reduce depression in caregivers. An American landmark study reported substantial beneficial effects of a multifaceted intervention where family meetings had a central place on depression in family caregivers as well as on delay of institutionalization of patients. These effects were not replicated in other countries yet. We perform the first trial comparing only structured family meetings with significant others versus usual care among primary family caregivers of community dwelling demented patients and measure the effectiveness on both depression and anxiety in the primary caregiver, both on disorder and symptom levels. Methods/design In this randomized controlled trial effectiveness as well as cost-effectiveness of family meetings is evaluated. The intervention group receives four family meetings with family and close friends of the primary family caregiver of a community dwelling patient with a clinical diagnosis of dementia. Dyads of patients and their primary caregiver are followed up to one year after baseline assessment. The main outcome measures are the incidence of anxiety and depressive disorders assessed with the Mini-International Neuropsychiatric Interview (MINI) and the severity of anxiety and depressive symptoms in caregivers is measured by validated self report instruments: the Centre for Epidemiologic Studies Depression Scale (CES-D) for depression and the anxiety scales of the Hospital Anxiety and Depression scales (HADS) for anxiety. The economic evaluation is performed from a societal perspective. Discussion By evaluating the effectiveness of only structured family meetings organized in the Netherlands, this study will contribute to the existing literature about the value of psychosocial interventions for dementia caregivers. Trial registration Dutch Trial Registry ISRCTN90163486
- Published
- 2008
- Full Text
- View/download PDF
27. (Cost)-effectiveness of family meetings on indicated prevention of anxiety and depressive symptoms and disorders of primary family caregivers of patients with dementia: design of a randomized controlled trial.
- Author
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Joling KJ, van Hout HP, Scheltens P, Vernooij-Dassen M, van den Berg B, Bosmans J, Gillissen F, Mittelman M, van Marwijk HW, Joling, Karlijn J, van Hout, Hein P J, Scheltens, Philip, Vernooij-Dassen, Myrra, van den Berg, Bernard, Bosmans, Judith, Gillissen, Freek, Mittelman, Mary, and van Marwijk, Harm W J
- Abstract
Background: Dementia is a major public health problem with enormous costs to society and major consequences for both patients and their relatives. Family members of persons with dementia provide much of the care for older adults with dementia in the community. Caring for a demented relative is not easy and fraught with emotional strain, distress, and physical exhaustion. Family caregivers of dementia patients have an extremely high risk developing affective disorders such as major depression and anxiety disorder. Family meetings appear to be among the most powerful psychosocial interventions to reduce depression in caregivers. An American landmark study reported substantial beneficial effects of a multifaceted intervention where family meetings had a central place on depression in family caregivers as well as on delay of institutionalization of patients. These effects were not replicated in other countries yet. We perform the first trial comparing only structured family meetings with significant others versus usual care among primary family caregivers of community dwelling demented patients and measure the effectiveness on both depression and anxiety in the primary caregiver, both on disorder and symptom levels.Methods/design: In this randomized controlled trial effectiveness as well as cost-effectiveness of family meetings is evaluated. The intervention group receives four family meetings with family and close friends of the primary family caregiver of a community dwelling patient with a clinical diagnosis of dementia. Dyads of patients and their primary caregiver are followed up to one year after baseline assessment. The main outcome measures are the incidence of anxiety and depressive disorders assessed with the Mini-International Neuropsychiatric Interview (MINI) and the severity of anxiety and depressive symptoms in caregivers is measured by validated self report instruments: the Centre for Epidemiologic Studies Depression Scale (CES-D) for depression and the anxiety scales of the Hospital Anxiety and Depression scales (HADS) for anxiety. The economic evaluation is performed from a societal perspective.Discussion: By evaluating the effectiveness of only structured family meetings organized in the Netherlands, this study will contribute to the existing literature about the value of psychosocial interventions for dementia caregivers.Trial Registration: Dutch Trial Registry ISRCTN90163486. [ABSTRACT FROM AUTHOR]- Published
- 2008
- Full Text
- View/download PDF
28. Differential effects of pharmaceuticals and insecticides on swimming behaviour and survival in Gammarus pulex.
- Author
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Versteegen E, Hofman V, Matser A, Gillissen F, Peeters ETHM, Roessink I, and van den Brink PJ
- Subjects
- Animals, Behavior, Animal drug effects, Neonicotinoids toxicity, Nitro Compounds toxicity, Citalopram toxicity, Water Pollutants, Chemical toxicity, Amphipoda physiology, Amphipoda drug effects, Swimming, Insecticides toxicity, Chlorpyrifos toxicity
- Abstract
Many freshwater systems are continuously exposed to waste streams like municipal wastewater and agricultural runoff, leading to exposure to chemicals that can cause mortality and behavioural changes in aquatic organisms. While research has advanced our understanding of pesticide effects on behaviour of aquatic organisms, the impacts of pharmaceuticals are less understood. Psychopharmaceuticals are particularly interesting because they can act on nervous systems, potentially affecting the behaviour of aquatic organisms. Sublethal behavioural effects can be crucial in ecotoxicological research for environmental pharmaceuticals and are often detected below lethal concentrations. Gammarids, especially Gammarus pulex, are widely used in ecotoxicological studies due to their ecological role and sensitivity to pollutants. This study aims to evaluate the sensitivity of six swimming behaviour endpoints in G. pulex compared to the conventional endpoints immobility and mortality, using different chemicals with distinct modes of action: insecticides imidacloprid and chlorpyrifos and the pharmaceuticals carbamazepine and citalopram. After a 2-hour exposure, the mobile organisms were assessed for their swimming speed, acceleration, curvature, thigmotaxis and startle response (magnitude and duration). Our study reveals that G. pulex exhibits varied behavioural responses to different chemical pollutants. While behavioural endpoints can indicate harmful effects on aquatic organisms, they are not consistently more sensitive than traditional endpoints, such as immobility and mortality. The insecticides imidacloprid and chlorpyrifos show development of immobility and mortality without prior sublethal behavioural effects, suggesting a limited utility of behavioural endpoints as early warning indicators. In contrast, the pharmaceuticals carbamazepine and citalopram demonstrate adverse effects through behavioural changes before immobility and mortality occur. Further research is essential to understand the mechanisms underlying these varying sensitivities of behavioural endpoints to different compounds, emphasising the importance of considering both chemical type and endpoint relevance in toxicity testing protocols., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Paul van den Brink reports financial support was provided by Wageningen University & Research. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2025
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29. Impact of COVID-19 pandemic on mortality rate in memory clinic patients.
- Author
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Bakker ED, van Maurik IS, Zwan MD, Gillissen F, van der Veere PJ, Bouwman FH, Pijnenburg YAL, and van der Flier WM
- Abstract
Introduction: We investigated whether mortality in memory clinic patients changed due to coronavirus disease 2019 (COVID-19) pandemic., Methods: We included patients from the Amsterdam Dementia Cohort: (1) n = 923 pandemic patients (baseline visit: 2017-2018, follow-up: until 2021), and (2) n = 830 historical control patients (baseline visit: 2015-2016, follow-up: until 2019). Groups were well-balanced. We compared mortality during pandemic with historical control patients using Cox regression. Differences in cause of death between groups were explored using Fisher's exact test., Results: Pandemic patients had a higher risk of mortality than historical control patients (hazard ratio [HR] [95% confidence interval {CI}] = 1.34 [1.05-1.70]). Stratified for syndrome diagnosis, the effect remained significant in dementia patients (HR [95% CI] = 1.35 [1.03-1.78]). Excluding patients who died of COVID-19-infection, the higher mortality risk in pandemic patients attenuated (HR [95% CI] = 1.24 [0.97-1.58]). Only the difference in cause of death between pandemic patients and historical control patients for death to COVID-19-infection ( p = 0.001) was observed., Conclusion: Memory clinic patients had increased mortality risk during COVID-19 compared to historical control patients, attributable to dementia patients., Highlights: We investigated if mortality rates in memory clinic patients changed due to COVID-19 pandemic.We included patients along the cognitive continuum, including SCD, MCI, and dementia.We used a well-balanced historical control group.Memory clinic patients had higher risk for mortality during COVID-19 lockdown.Our results indicate that excess mortality is mainly caused by death to COVID-19 infection., Competing Interests: Research programs of W.M.F. have been funded by ZonMW, NWO, EU‐FP7, EU‐JPND, Alzheimer Nederland, CardioVascular Onderzoek Nederland, Health∼Holland, Topsector Life Sciences & Health, stichting Dioraphte, Gieskes‐Strijbis fonds, stichting Equilibrio, Pasman Stichting, Biogen MA Inc, Boehringer Ingelheim, Life‐ MI, AVID, Roche BV, Fujifilm, Combinostics. W.M.F. is consultant to Oxford Health Policy Forum CIC, Roche, and Biogen MA Inc. W.M.F. has been an invited speaker at Boehringer Ingelheim, Biogen MA Inc, Danone, Eisai, WebMD Neurology (Medscape). All funding is paid to her institution. W.M.F. participated in an advisory board of Biogen MA Inc. W.M.F. is associate editor at Brain. I.S.M. received a consultancy fee (paid to the university) from Roche. F.H.B. received Optina diagnostics payments and roche, biogen payments to her institution. Y.A.L.P. has received funding from the Dutch Brain Foundation and the Mooiste Contact Fonds (both paid to her institution). The other authors report no financial disclosures or conflicts of interest. The sponsors had no involvement in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the manuscript for publication. Author disclosures are available in the Supporting Information., (© 2024 The Authors. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)
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- 2024
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30. The reporting of neuropsychiatric symptoms in electronic health records of individuals with Alzheimer's disease: a natural language processing study.
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Eikelboom WS, Singleton EH, van den Berg E, de Boer C, Coesmans M, Goudzwaard JA, Vijverberg EGB, Pan M, Gouw C, Mol MO, Gillissen F, Fieldhouse JLP, Pijnenburg YAL, van der Flier WM, van Swieten JC, Ossenkoppele R, Kors JA, and Papma JM
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- Humans, Electronic Health Records, Natural Language Processing, Neuropsychological Tests, Alzheimer Disease diagnosis, Alzheimer Disease epidemiology, Alzheimer Disease psychology, Apathy
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Background: Neuropsychiatric symptoms (NPS) are prevalent in the early clinical stages of Alzheimer's disease (AD) according to proxy-based instruments. Little is known about which NPS clinicians report and whether their judgment aligns with proxy-based instruments. We used natural language processing (NLP) to classify NPS in electronic health records (EHRs) to estimate the reporting of NPS in symptomatic AD at the memory clinic according to clinicians. Next, we compared NPS as reported in EHRs and NPS reported by caregivers on the Neuropsychiatric Inventory (NPI)., Methods: Two academic memory clinic cohorts were used: the Amsterdam UMC (n = 3001) and the Erasmus MC (n = 646). Patients included in these cohorts had MCI, AD dementia, or mixed AD/VaD dementia. Ten trained clinicians annotated 13 types of NPS in a randomly selected training set of n = 500 EHRs from the Amsterdam UMC cohort and in a test set of n = 250 EHRs from the Erasmus MC cohort. For each NPS, a generalized linear classifier was trained and internally and externally validated. Prevalence estimates of NPS were adjusted for the imperfect sensitivity and specificity of each classifier. Intra-individual comparison of the NPS classified in EHRs and NPS reported on the NPI were conducted in a subsample (59%)., Results: Internal validation performance of the classifiers was excellent (AUC range: 0.81-0.91), but external validation performance decreased (AUC range: 0.51-0.93). NPS were prevalent in EHRs from the Amsterdam UMC, especially apathy (adjusted prevalence = 69.4%), anxiety (adjusted prevalence = 53.7%), aberrant motor behavior (adjusted prevalence = 47.5%), irritability (adjusted prevalence = 42.6%), and depression (adjusted prevalence = 38.5%). The ranking of NPS was similar for EHRs from the Erasmus MC, although not all classifiers obtained valid prevalence estimates due to low specificity. In both cohorts, there was minimal agreement between NPS classified in the EHRs and NPS reported on the NPI (all kappa coefficients < 0.28), with substantially more reports of NPS in EHRs than on NPI assessments., Conclusions: NLP classifiers performed well in detecting a wide range of NPS in EHRs of patients with symptomatic AD visiting the memory clinic and showed that clinicians frequently reported NPS in these EHRs. Clinicians generally reported more NPS in EHRs than caregivers reported on the NPI., (© 2023. The Author(s).)
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- 2023
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31. Steeper memory decline after COVID-19 lockdown measures.
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Bakker ED, van der Pas SL, Zwan MD, Gillissen F, Bouwman FH, Scheltens P, van der Flier WM, and van Maurik IS
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- Humans, Female, Middle Aged, Aged, Male, Neuropsychological Tests, Communicable Disease Control, Memory Disorders epidemiology, Memory Disorders etiology, COVID-19, Cognitive Dysfunction diagnosis, Dementia, Alzheimer Disease diagnosis
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Background: During COVID-19 lockdown measures, memory clinic patients reported worries for faster cognitive decline, due to loss of structure and feelings of loneliness and depression. We aimed to investigate the impact of the COVID-19 lockdown on rate of cognitive decline in a mixed memory clinic population, compared to matched historical controls., Methods: We included patients who visited Alzheimer Center Amsterdam 6 months to 1 week before the first Dutch COVID-19 lockdown, and had a second visit 1 year later, after this lockdown period (n = 113; 66 ± 7 years old; 30% female; n = 55 dementia, n = 31 mild cognitive impairment (MCI), n = 18 subjective cognitive decline (SCD), n = 9 postponed diagnosis). Historical controls (visit in 2016/2017 and second visit 1 year later (n = 640)) were matched 1:1 to lockdown patients by optimal Mahalanobis distance matching (both groups n = 113). Groups were well matched. Differences between lockdown patients and historical controls over time in Mini-Mental State Examination, Trail Making Test part A and B, Rey-Auditory Verbal Learning Test (RAVLT) immediate and delayed recall, and category fluency scores were analyzed using linear mixed effect models with random intercepts. We examined differences in rate of cognitive decline between whole groups, and after stratification in SCD, MCI, and dementia separately., Results: Lockdown patients had a faster rate of memory decline compared to controls on both RAVLT immediate [B(SE) = - 2.62 (1.07), p = 0.015] and delayed recall [B(SE) = - 1.07 (0.34), p = 0.002]. Stratification by syndrome diagnosis showed that this effect was largely attributable to non-demented participants, as we observed faster memory decline during lockdown in SCD and MCI (RAVLT immediate [SCD: B(SE) = - 6.85 (2.97), p = 0.027; MCI: B(SE) = - 6.14 (1.78), p = 0.001] and delayed recall [SCD: B(SE) = - 2.45 (1.11), p = 0.035; MCI: B(SE) = - 1.50 (0.51), p = 0.005]), but not in dementia., Conclusion: Memory clinic patients, specifically in pre-dementia stages, showed faster memory decline during COVID-19 lockdown, providing evidence that lockdown regulations had a deleterious effect on brain health. In individuals that may have been able to deal with accumulating, subclinical neuropathology under normal and structured circumstances, the additional stress of lockdown regulations may have acted as a "second hit," resulting in less beneficial disease trajectory., (© 2023. The Author(s).)
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- 2023
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32. A caregiver's perspective on clinically relevant symptoms in behavioural variant frontotemporal dementia: tools for disease management and trial design.
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Fieldhouse JLP, van Dijk G, Gillissen F, van Engelen ME, de Boer SCM, Dols A, van der Waal HJ, Regeer BJ, Vijverberg EGB, and Pijnenburg YAL
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- Humans, Disease Management, Clinical Trials as Topic, Research Design, Caregivers psychology, Frontotemporal Dementia psychology, Frontotemporal Dementia therapy
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Background: Adequate detection of symptoms and disease progression in behavioural variant frontotemporal dementia (bvFTD) is complex. Dementia cohorts usually utilize cognitive and functional measures, which fail to detect dominant behavioural and social cognitive deficits in bvFTD. Moreover, since patients typically have a loss of insight, caregivers are important informants. This is the first qualitative study to investigate caregiver relevant symptoms during the disease course of bvFTD, aiming to improve tools for diagnosis, progression, and future clinical trials., Methods: Informal caregivers of patients in different disease stages of bvFTD (N = 20) were recruited from the neurology outpatient clinic of the Amsterdam UMC and a patient organization for peer support in the Netherlands. Their perspectives on clinical relevance were thoroughly explored during individual semi-structured interviews. Inductive content analysis with open coding was performed by two researchers independently to establish overarching themes and patterns., Results: Caregivers reported a variety of symptoms, in which (i) loss of emotional connection, (ii) preoccupation and restlessness, and (iii) apathy and dependency compose major themes of relevance for diagnosis and treatment. Within heterogeneous disease trajectories, symptom presence differed between stages and among individuals, which is relevant in the context of progression and outcome measures. Significant socio-emotional changes dominated in early stages, while severe cognitive, behavioural, and physical deterioration shifted focus from predominant personality change to quality of life in later stages., Conclusions: Caregiver perspectives on target symptoms in bvFTD differ according to clinical stage and patient-caregiver characteristics, with significant socio-emotional changes characterizing early stages. These findings call for more appropriate tools and symptomatic treatments, as well as a personalized approach in treatment of bvFTD and a focus on early stage interventions in clinical trial design., (© 2022 The Authors. Psychogeriatrics published by John Wiley & Sons Australia, Ltd on behalf of Japanese Psychogeriatric Society.)
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- 2023
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33. Determining the Minimal Important Change of Everyday Functioning in Dementia: Pursuing Clinical Meaningfulness.
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Dubbelman MA, Verrijp M, Terwee CB, Jutten RJ, Postema MC, Barkhof F, Berckel BNM, Gillissen F, Teeuwen V, Teunissen C, van de Flier WM, Scheltens P, and Sikkes SAM
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- Atrophy, Caregivers, Female, Humans, Longitudinal Studies, Male, Retrospective Studies, Activities of Daily Living, Alzheimer Disease psychology
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Background and Objectives: Decline in everyday functioning is a key clinical change in Alzheimer disease and related disorders (ADRD). An important challenge remains the determination of what constitutes a clinically meaningful change in everyday functioning. We aimed to investigate this by establishing the minimal important change (MIC): the smallest amount of change that has a meaningful effect on patients' lives. We retrospectively investigated meaningful change in a memory clinic cohort., Methods: In the first, qualitative part of the study, community-recruited informal caregivers of patients with ADRD and memory clinic clinicians completed a survey in which they judged various situations representing changes in everyday functioning. Their judgments of meaningful change were used to determine thresholds for MIC, both for decline and improvement, on the Amsterdam Instrumental Activities of Daily Living (IADL) Questionnaire. In the second, quantitative part, we applied these values in an independent longitudinal cohort study of unselected memory clinic patients., Results: MIC thresholds were established at the average threshold of caregivers (N = 1,629; 62.4 ± 9.5 years; 77% female) and clinicians (N = 13): -2.2 points for clinically meaningful decline and +5.0 points for clinically meaningful improvement. Memory clinic patients (N = 230; 64.3 ± 7.7 years; 39% female; 60% dementia diagnosis) were followed for 1 year, 102 (45%) of whom showed a decline larger than the MIC, after a mean of 6.7 ± 3.5 months. Patients with a dementia diagnosis and more atrophy of the medial temporal lobe had larger odds (odds ratio [OR] = 3.4, 95% CI [1.5-7.8] and OR = 5.0, 95% CI [1.2-20.0], respectively) for passing the MIC threshold for decline than those with subjective cognitive complaints and no atrophy., Discussion: We were able to operationalize clinically meaningful decline in IADL by determining the MIC. The usefulness of the MIC was supported by our findings from the clinical sample that nearly half of a sample of unselected memory clinic patients showed a meaningful decline in less than a year. Disease stage and medial temporal atrophy were predictors of functional decline greater than the MIC. Our findings provide guidance in interpreting changes in IADL and may help evaluate treatment effects and monitor disease progression., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)
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- 2022
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34. Psychosocial Effects of COVID-19 Measures on (Pre-)Dementia Patients During Second Lockdown.
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Bakker ED, van Maurik IS, Mank A, Zwan MD, Waterink L, van den Buuse S, van den Broeke JR, Gillissen F, van de Beek M, Lemstra E, van den Bosch KA, van Leeuwenstijn M, Bouwman FH, Scheltens P, and van der Flier WM
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- Caregivers psychology, Communicable Disease Control, Humans, Pandemics, COVID-19, Dementia epidemiology, Dementia psychology
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Background: The COVID-19 pandemic poses enormous social challenges, especially during lockdown. People with cognitive decline and their caregivers are particularly at risk of lockdown consequences., Objective: To investigate psychosocial effects in (pre-)dementia patients and caregivers during second lockdown and compare effects between first and second lockdown., Methods: We included n = 511 (pre-)dementia patients and n = 826 caregivers from the Amsterdam Dementia Cohort and via Alzheimer Nederland. All respondents completed a self-designed survey on psychosocial effects of COVID-19. We examined relations between experienced support and psychosocial and behavioral symptoms using logistic regression. In a subset of patients and caregivers we compared responses between first and second lockdown using generalized estimating equation (GEE)., Results: The majority of patients (≥58%) and caregivers (≥60%) reported that family and friends, hobbies, and music helped them cope. Support from family and friends was strongly related to less negative feelings in patients (loneliness: OR = 0.3[0.1-0.6]) and caregivers (loneliness: OR = 0.2[0.1-0.3]; depression: OR = 0.4[0.2-0.5]; anxiety: OR = 0.4[0.3-0.6]; uncertainty: OR = 0.3[0.2-0.5]; fatigue: OR = 0.3[0.2-0.4]; stress: OR = 0.3[0.2-0.5]). In second lockdown, less psychosocial and behavioral symptoms were reported compared to first lockdown (patients; e.g., anxiety: 22% versus 13%, p = 0.007; apathy: 27% versus 8%, p < 0.001, caregivers; e.g., anxiety: 23% versus 16%, p = 0.033; patient's behavioral problems: 50% versus 35%, p < 0.001). Patients experienced more support (e.g., family and friends: 52% versus 93%, p < 0.001; neighbors: 28% versus 66%, p < 0.001)., Conclusion: During second lockdown, patients and caregivers adapted to challenges posed by lockdown, as psychosocial and behavioral effects decreased, while patients experienced more social support compared to first lockdown. Support from family and friends is a major protective factor for negative outcomes in patients and caregivers.
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- 2022
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35. Clinical Phenotypes of Behavioral Variant Frontotemporal Dementia by Age at Onset.
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Fieldhouse JLP, Gossink FT, Feenstra TC, de Boer SCM, Lemstra AW, Prins ND, Bouwman F, Koene T, Rhodius-Meester HFM, Gillissen F, Teunissen CE, van der Flier WM, Scheltens P, Dols A, Vijverberg EGB, and Pijnenburg YAL
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- Adult, Age of Onset, Aged, Aged, 80 and over, Anxiety physiopathology, Anxiety psychology, Apathy physiology, Delusions physiopathology, Delusions psychology, Female, Frontotemporal Dementia psychology, Hallucinations physiopathology, Hallucinations psychology, Humans, Inhibition, Psychological, Irritable Mood physiology, Male, Memory Disorders physiopathology, Memory Disorders psychology, Middle Aged, Mood Disorders physiopathology, Mood Disorders psychology, Phenotype, Severity of Illness Index, Frontotemporal Dementia physiopathology, Mortality, Neuropsychological Tests
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Background: Behavioral variant frontotemporal dementia (bvFTD) is generally considered a young-onset dementia, although age at onset is highly variable. While several studies indicate clinical differences regarding age at onset, no biomarker validated cohort studies with updated clinical criteria have been performed., Objective: We aimed to examine behavior, cognition, and mortality over the full age spectrum in a cohort of bvFTD patients with neuroimaging, genetic, or histopathological confirmation and exclusion of positive Alzheimer's disease biomarkers or severe cerebrovascular damage., Methods: In total, 315 patients with a clinical diagnosis of probable or definite bvFTD were included from the Amsterdam Dementia Cohort and grouped into quartiles by age-at-diagnosis. Neuropsychiatric symptoms and cognitive functioning were assessed with the neuropsychiatric inventory, the geriatric depression scale and a neuropsychological test battery. Data on mortality was obtained from the Dutch municipal register. Associations between age-at-diagnosis and clinical features and mortality risk were examined., Results: Age-at-diagnosis ranged from 26 to 85 years and established quartiles with mean ages of 52±6, 61±2, 66±2, and 74±3 years. In the total sample, 44.4%exceeded an age of 65 years at time of diagnosis. Earlier age-at-diagnosis was associated with more severe behavioral symptoms, while later age-at-diagnosis was associated with more severe memory impairment. Unexpectedly, mortality risk was not associated with age-at-diagnosis., Conclusion: In bvFTD, symptom profile is associated with age-at-diagnosis. This should be taken into account with regard to diagnostics, patient management, and trial design. Additionally, based on our sample, the prevalence of late-onset bvFTD is higher than generally thought.
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- 2021
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36. Psychosocial Effects of Corona Measures on Patients With Dementia, Mild Cognitive Impairment and Subjective Cognitive Decline.
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van Maurik IS, Bakker ED, van den Buuse S, Gillissen F, van de Beek M, Lemstra E, Mank A, van den Bosch KA, van Leeuwenstijn M, Bouwman FH, Scheltens P, and van der Flier WM
- Abstract
Background: The recent COVID-19 pandemic is not only a major healthcare problem in itself, but also poses enormous social challenges. Though nursing homes increasingly receive attention, the majority of people with cognitive decline and dementia live at home. We aimed to explore the psychosocial effects of corona measures in memory clinic (pre-)dementia patients and their caregivers. Methods: Between April 28th and July 13th 2020, n = 389 patients of Alzheimer center Amsterdam [ n = 121 symptomatic (age = 69 ± 6, 33%F, MMSE = 23 ± 5), n = 268 cognitively normal (age = 66 ± 8, 40% F, MMSE = 29 ± 1)] completed a survey on psychosocial effects of the corona measures. Questions related to social isolation, worries for faster cognitive decline, behavioral problems and discontinuation of care. In addition, n = 147 caregivers of symptomatic patients completed a similar survey with additional questions on caregiver burden. Results: Social isolation was experienced by n = 42 (35%) symptomatic and n = 67 (25%) cognitively normal patients and two third of patients [ n = 129 (66%); n = 58 (75%) symptomatic, n = 71 (61%) cognitively normal] reported that care was discontinued. Worries for faster cognitive decline were existed in symptomatic patients [ n = 44 (44%)] and caregivers [ n = 73 (53%)], but were also reported by a subgroup of cognitively normal patients [ n = 27 (14%)]. Both patients [ n = 56 (46%) symptomatic, n = 102 (38%) cognitively normal] and caregivers [ n = 72 (48%)] reported an increase in psychological symptoms. More than three quarter of caregivers [ n = 111(76%)] reported an increase in patients' behavioral problems. A higher caregiver burden was experienced by n = 69 (56%) of caregivers and n = 43 (29%) of them reported that a need for more support. Discontinuation of care (OR = 3.3 [1.3-7.9]), psychological (OR = 4.0 [1.6-9.9]) and behavioral problems (OR = 3.0 [1.0-9.0]) strongly related to experiencing a higher caregiver burden. Lastly, social isolation (OR = 3.2 [1.2-8.1]) and psychological symptoms (OR = 8.1 [2.8-23.7]) were red flags for worries for faster cognitive decline. Conclusion: Not only symptomatic patients, but also cognitively normal patients express worries for faster cognitive decline and psychological symptoms. Moreover, we identified patients who are at risk of adverse outcomes of the corona measures, i.e., discontinued care, social isolation, psychological and behavioral problems. This underlines the need for health care professionals to provide ways to warrant the continuation of care and support (informal) networks surrounding patients and caregivers to mitigate the higher risk of negative psychosocial effects., (Copyright © 2020 van Maurik, Bakker, van den Buuse, Gillissen, van de Beek, Lemstra, Mank, van den Bosch, van Leeuwenstijn, Bouwman, Scheltens and van der Flier.)
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- 2020
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37. Influence of pH on the toxicity of ionisable pharmaceuticals and personal care products to freshwater invertebrates.
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Sun M, Duker RQ, Gillissen F, Van den Brink PJ, Focks A, and Rico A
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- Amphipoda drug effects, Animals, Cosmetics chemistry, Ecosystem, Enrofloxacin chemistry, Enrofloxacin toxicity, Hydrogen-Ion Concentration, Models, Theoretical, Risk Assessment, Snails drug effects, Toxicity Tests, Triclosan chemistry, Triclosan toxicity, Water Pollutants, Chemical chemistry, Aquatic Organisms drug effects, Cosmetics toxicity, Fresh Water chemistry, Pharmaceutical Preparations chemistry, Water Pollutants, Chemical toxicity
- Abstract
The majority of pharmaceuticals and personal health-care products are ionisable molecules at environmentally relevant pHs. The ionization state of these molecules in freshwater ecosystems may influence their toxicity potential to aquatic organisms. In this study we evaluated to what extent varying pH conditions may influence the toxicity of the antibiotic enrofloxacin (ENR) and the personal care product ingredient triclosan (TCS) to three freshwater invertebrates: the ephemeropteran Cloeon dipterum, the amphipod Gammarus pulex and the snail Physella acuta. Acute toxicity tests were performed by adjusting the water pH to four nominal levels: 6.5, 7.0, 7.5 and 8.0. Furthermore, we tested the efficiency of three toxicity models with different assumptions regarding the uptake and toxicity potential of ionisable chemicals with the experimental data produced in this study. The results of the toxicity tests indicate that pH fluctuations of only 1.5 units can influence EC50-48 h and EC50-96 h values by a factor of 1.4-2.7. Overall, the model that only focuses on the fraction of neutral chemical and the model that takes into account ion-trapping of the test molecules showed the best performance, although present limitations to perform risk assessments across a wide pH range (i.e., well above or below the substance pKa). Under such conditions, the model that takes into account the toxicity of the neutral and the ionized chemical form is preferred. The results of this study show that pH fluctuations can have a considerable influence on toxicity thresholds, and should therefore be taken into account for the risk assessment of ionisable pharmaceuticals and personal health-care products. Based on our results, an assessment factor of at least three should be used to account for toxicity differences between standard laboratory and field pH conditions. The models evaluated here can be used to perform refined risk assessments by taking into account the influence of temporal and spatial pH fluctuations on aquatic toxicity., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)
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- 2020
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38. Horizontal and vertical diversity jointly shape food web stability against small and large perturbations.
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Zhao Q, Van den Brink PJ, Carpentier C, Wang YXG, Rodríguez-Sánchez P, Xu C, Vollbrecht S, Gillissen F, Vollebregt M, Wang S, and De Laender F
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- Biodiversity, Food Chain
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The biodiversity of food webs is composed of horizontal (i.e. within trophic levels) and vertical diversity (i.e. the number of trophic levels). Understanding their joint effect on stability is a key challenge. Theory mostly considers their individual effects and focuses on small perturbations near equilibrium in hypothetical food webs. Here, we study the joint effects of horizontal and vertical diversity on the stability of hypothetical (modelled) and empirical food webs. In modelled food webs, horizontal and vertical diversity increased and decreased stability, respectively, with a stronger positive effect of producer diversity on stability at higher consumer diversity. Experiments with an empirical plankton food web, where we manipulated horizontal and vertical diversity and measured stability from species interactions and from resilience against large perturbations, confirmed these predictions. Taken together, our findings highlight the need to conserve horizontal biodiversity at different trophic levels to ensure stability., (© 2019 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.)
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- 2019
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39. Effects of temperature, genetic variation and species competition on the sensitivity of algae populations to the antibiotic enrofloxacin.
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Rico A, Zhao W, Gillissen F, Lürling M, and Van den Brink PJ
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- Chlorophyll analysis, Chlorophyll A, Dose-Response Relationship, Drug, Ecosystem, Enrofloxacin, Microcystis genetics, Photosynthesis drug effects, Scenedesmus genetics, Species Specificity, Temperature, Anti-Bacterial Agents toxicity, Fluoroquinolones toxicity, Genetic Variation, Microcystis drug effects, Scenedesmus drug effects, Water Pollutants, Chemical toxicity
- Abstract
Primary producers are amongst the most sensitive organisms to antibiotic pollution in aquatic ecosystems. To date, there is little information on how different environmental conditions may affect their sensitivity to antibiotics. In this study we assessed how temperature, genetic variation and species competition may affect the sensitivity of the cyanobacterium Microcystis aeruginosa and the green-algae Scenedesmus obliquus to the antibiotic enrofloxacin. First, we performed single-species tests to assess the toxicity of enrofloxacin under different temperature conditions (20°C and 30°C) and to assess the sensitivity of different species strains using a standard temperature (20°C). Next, we investigated how enrofloxacin contamination may affect the competition between M. aeruginosa and S. obliquus. A competition experiment was performed following a full factorial design with different competition treatments, defined as density ratios (i.e. initial bio-volume of 25/75%, 10/90% and 1/99% of S. obliquus/M. aeruginosa, respectively), one 100% S. obliquus treatment and one 100% M. aeruginosa treatment, and four different enrofloxacin concentrations (i.e. control, 0.01, 0.05 and 0.10mg/L). Growth inhibition based on cell number, bio-volume, chlorophyll-a concentration as well as photosynthetic activity were used as evaluation endpoints in the single-species tests, while growth inhibition based on measured chlorophyll-a was primarily used in the competition experiment. M. aeruginosa photosynthetic activity was found to be the most sensitive endpoint to enrofloxacin (EC50-72h =0.02mg/L), followed by growth inhibition based on cell number. S. obliquus was found to be slightly more sensitive at 20°C than at 30°C (EC50-72h cell number growth inhibition of 38 and 41mg/L, respectively), whereas an opposite trend was observed for M. aeruginosa (0.047 and 0.037mg/L, respectively). Differences in EC50-72h values between algal strains of the same species were within a factor of two. The competition experiment showed that M. aeruginosa growth can be significantly reduced in the presence of S. obliquus at a density ratio of 75/25% M. aeruginosa/S. obliquus, showing a higher susceptibility to enrofloxacin than in the single-species test. The results of this study confirm the high sensitivity of cyanobacteria to antibiotics and show that temperature and inter-strain genetic variation may have a limited influence on their response to them. The results of the competition experiment suggest that the structure of primary producer communities can be affected, at least temporarily, at antibiotic concentrations close to those that have been measured in the environment., (Copyright © 2017 Elsevier Inc. All rights reserved.)
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- 2018
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40. Factors associated with sustainability of 2 quality improvement programs after achieving early implementation success. A qualitative case study.
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Ament SMC, Gillissen F, Moser A, Maessen JMC, Dirksen CD, von Meyenfeldt MF, and van der Weijden T
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- Breast Neoplasms surgery, Colonic Neoplasms surgery, Cost-Benefit Analysis, Health Services Research, Hospital Administration, Humans, Leadership, Length of Stay, Netherlands, Organizational Culture, Organizational Innovation, Perioperative Care methods, Perioperative Care standards, Postoperative Care economics, Program Evaluation, Qualitative Research, Quality Improvement economics, Quality Improvement standards, Postoperative Care methods, Postoperative Care standards, Quality Improvement organization & administration
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Rationale, Aims, and Objectives: Sustainability of innovations is a relatively new concept in health care research and has become an issue of growing interest. The current study explored factors related to the sustainability of 2 multidisciplinary hospital-based programs 3 to 6 years after achieving early implementation success., Method: An exploratory qualitative study was conducted into 2 implementation cases, an Enhanced Recovery After Surgery program for colorectal surgery and a short-stay program for breast cancer surgery. Semistructured interviews were held with key persons involved in the care process in 14 hospitals from both cases minimally 3 years after the implementation, between March 2012 and May 2013. The Consolidated Framework for Implementation Research was used to direct the development of the interview guide, during data collection and during analysis. A directed content analysis was performed., Results: A total of 21 interviews with 26 individuals were held, 18 regarding the Enhanced Recovery After Surgery case and 8 regarding the short-stay program case. Respondents mentioned the following factors associated with sustainability of the programs: modification and adaptability of the program, cost-effectiveness, institutionalization into existing systems, short communication lines within the multidisciplinary team, an innovative culture, benefits for patients, cosmopolitanism, the existence of external policies and incentives, trust and belief in the program, and spread of the program to other settings. Two factors are not covered by the Consolidated Framework for Implementation Research, ie, modification of the program over the years and spread of the program to other contexts., Conclusions: The factors associated with sustainability put forward in both cases were largely the same. Leadership and the implementation project were not mentioned as having influenced the long-term sustainability of the benefits achieved. Sustainability of the innovations is influenced by determinants stemming from all ecological levels of the health care system and demands continuous effort in the postimplementation phase., (© 2017 John Wiley & Sons, Ltd.)
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- 2017
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41. Patients' and caregivers' views on conversations and shared decision making in diagnostic testing for Alzheimer's disease: The ABIDE project.
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Kunneman M, Pel-Littel R, Bouwman FH, Gillissen F, Schoonenboom NSM, Claus JJ, van der Flier WM, and Smets EMA
- Abstract
Introduction: This study aims to assess patients' and caregivers' views on and experiences with (1) decisions about diagnostic testing for Alzheimer's disease (AD) and (2) receiving test results., Methods: We conducted separate focus groups with patients from three hospitals who underwent diagnostic testing for AD ( N = 11) and their caregivers ( N = 11). Audio recordings were transcribed verbatim and analyzed using MaxQDA., Results: Patients and caregivers preferred and perceived active involvement in decision making, but the decision to initiate diagnostic testing seems to be made before the clinician-patient encounter. Patients and caregivers indicate that decisions are driven by a strong need to explain the patient's symptoms. They missed information on why different diagnostic tests were used, what the results of these tests were, and to what extent these results were (ab)normal., Discussion: The decision-making process around diagnostic testing for AD and the information provision before and after diagnostic testing could be improved.
- Published
- 2017
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42. [Doctor, is my mother suffering from dementia?]
- Author
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Scheltens P, Gillissen F, Bouwman FH, and van der Flier WM
- Subjects
- Diagnosis, Differential, Female, Humans, Netherlands, Activities of Daily Living, Alzheimer Disease diagnosis, General Practitioners
- Abstract
- The Netherlands health service features a stepwise diagnostic course in primary, secondary and tertiary care. In the diagnostic process for dementia the patient can go to the general practitioner, then to one of the 100 memory clinics and finally to one of the 4 academic Alzheimer centres.- The diagnostic process for dementia is described in the care practice guideline 'Dementia', the NHG (Dutch College of General Practitioners) practice guideline 'Dementia' and the multidisciplinary guideline 'Dementia diagnostics'.- Most patients will only have to follow part of this care chain before an adequate diagnosis is made and appropriate care can be implemented.- New validated instruments for dementia diagnostics have recently become available, including the Amsterdam instrumental activities of daily living (A-IADL) scale, biomarkers in cerebrospinal fluid (CSF) and the Medial temporal atrophy (MTA) scale for interpreting MRI scans.- The individual risk of dementia can be estimated using the MMSE score, MRI scans and the results of CSF investigations.
- Published
- 2017
43. Identification of promising strategies to sustain improvements in hospital practice: a qualitative case study.
- Author
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Ament SM, Gillissen F, Moser A, Maessen JM, Dirksen CD, von Meyenfeldt MF, and van der Weijden T
- Subjects
- Cooperative Behavior, Humans, Interviews as Topic, Length of Stay, Medical Staff, Hospital psychology, Qualitative Research, Recovery of Function, Hospitals standards, Postoperative Care standards, Quality Improvement
- Abstract
Background: A quality improvement collaborative is an intensive project involving a combination of implementation strategies applied in a limited "breakthrough" time window. After an implementation project, it is generally difficult to sustain its success. In the current study, sustainability was described as maintaining an implemented innovation and its benefits over a longer period of time after the implementation project has ended. The aim of the study was to explore potentially promising strategies for sustaining the Enhanced Recovery After Surgery (ERAS) programme in colonic surgery as perceived by professionals, three to six years after the hospital had successfully finished a quality improvement collaborative., Methods: A qualitative case study was performed to identify promising strategies to sustain key outcome variables related to the ERAS programme in terms of adherence, time needed for functional recovery and hospital length of stay (LOS), as achieved immediately after implementation. Ten hospitals were selected which had successfully implemented the ERAS programme in colonic surgery (2006-2009), with success defined as a median LOS of 6 days or less and protocol adherence rates above 70%. Fourteen semi-structured interviews were held with eighteen key participants of the care process three to six years after implementation, starting with the project leader in every hospital. The interviews started by confronting them with the level of sustained implementation results. A direct content analysis with an inductive coding approach was used to identify promising strategies. The mean duration of the interviews was 37 minutes (min 26 minutes - max 51 minutes)., Results: The current study revealed strategies targeting professionals and the organisation. They comprised internal audit and feedback on outcomes, small-scale educational booster meetings, reminders, changing the physical structure of the organisation, changing the care process, making work agreements and delegating responsibility, and involving a coordinator. A multifaceted self-driven promising strategy was applied in most hospitals, and in most hospitals promising strategies were suggested to sustain the ERAS programme., Conclusions: Joining a quality improvement collaborative may not be enough to achieve long-term normalisation of transformed care, and additional investments may be needed. The findings suggest that certain post-implementation strategies are valuable in sustaining implementation successes achieved after joining a quality improvement collaborative.
- Published
- 2014
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44. Explaining PAH desorption from sediments using Rock Eval analysis.
- Author
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Poot A, Jonker MTO, Gillissen F, and Koelmans AA
- Subjects
- Adsorption, Kinetics, Carbon analysis, Geologic Sediments analysis, Polycyclic Aromatic Hydrocarbons analysis
- Abstract
Here, we provide Rock Eval and black carbon (BC) characteristics and polycyclic aromatic hydrocarbon (PAH) distribution coefficients (KD) for sediments from the Danube, Elbe, Ebro, and Meuse river basins. PAH desorption kinetic parameters were determined using sequential Tenax extractions. We show that residual carbon (RC) from Rock Eval analysis is an adequate predictor of fast, slow, and very slow desorbing fractions of 4-ring PAHs. RC correlated better than BC, the latter constituting only 7% of RC. A dual domain sorption model was statistically superior to a single domain model in explaining KD for low molecular weight PAHs, whereas the opposite was observed for high molecular weight PAHs. Because particularly the 4-ring PAHs are bioavailable and relevant from a risk assessment perspective and because their fast desorbing fractions correlate best with RC, we recommend RC as a relevant characteristic for river sediments., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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45. Structured synchronous implementation of an enhanced recovery program in elective colonic surgery in 33 hospitals in The Netherlands.
- Author
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Gillissen F, Hoff C, Maessen JM, Winkens B, Teeuwen JH, von Meyenfeldt MF, and Dejong CH
- Subjects
- Aged, Clinical Protocols, Early Ambulation statistics & numerical data, Female, Guideline Adherence statistics & numerical data, Hospitals standards, Hospitals statistics & numerical data, Humans, Kaplan-Meier Estimate, Male, Netherlands, Outcome Assessment, Health Care, Perioperative Care standards, Perioperative Care statistics & numerical data, Program Evaluation, Proportional Hazards Models, Recovery of Function, Retrospective Studies, Colectomy, Elective Surgical Procedures, Length of Stay statistics & numerical data, Perioperative Care methods
- Abstract
Background: It has been clearly shown that after elective colorectal surgery patients benefit from multimodal perioperative care programs. The Dutch Institute for Health Care Improvement started a breakthrough project to implement a multimodal perioperative care program of enhanced recovery after surgery (ERAS). This pre/post noncontrolled study evaluated the success of large-scale implementation of the ERAS program for elective colonic surgery using the breakthrough series., Methods: A total of 33 hospitals participated in this breakthrough project during 2005-2009. Each hospital performed a retrospective chart review to gather information on traditionally treated patients (pre-ERAS group, n = 1,451). During the subsequent year patients were treated according to the ERAS program (ERAS group, n = 1 034). Outcomes were length of stay (LOS), functional recovery, adherence to the protocol, and determinants of reduced LOS., Results: Median LOS decreased significantly from 9 to 6 days (p < 0.001). In the ERAS group, functional recovery was reached within 3 days. Adherence to the protocol elements was high during the preoperative and perioperative phases but slightly lower during the postoperative phase. Younger age, female sex, American Society of Anesthesiologists grades I/II, and laparoscopic surgery were associated with decreased LOS. Care elements that positively influenced LOS were cessation of intravenous fluids and mobilization on postoperative day 1 and administration of laxatives postoperatively., Conclusions: The ERAS program was successfully implemented in one-third of all Dutch hospitals using the breakthrough series. Participating hospitals reduced the LOS by a median 3 days and were able to improve their standard of care in elective colonic surgery.
- Published
- 2013
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46. A new informant-based questionnaire for instrumental activities of daily living in dementia.
- Author
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Sikkes SA, de Lange-de Klerk ES, Pijnenburg YA, Gillissen F, Romkes R, Knol DL, Uitdehaag BM, and Scheltens P
- Subjects
- Aged, Dementia diagnosis, Female, Humans, Male, Middle Aged, Reproducibility of Results, Activities of Daily Living, Dementia psychology, Psychometrics methods, Surveys and Questionnaires
- Abstract
Background: Interference in everyday functioning is part of the diagnostic criteria for dementia. Questionnaires measuring "instrumental activities of daily living" (IADL) are used to measure this interference, but the psychometric quality of these questionnaires is often questioned. In addition, these questionnaires are less suited for early-onset patients. This is problematic, given the high frequency of relatively young patients in memory clinics. In this article, we describe the development and psychometric properties of a new informant-based IADL questionnaire aimed at detecting incipient dementia and appropriate for a broad age range., Methods: We defined IADL in consensus with experts and constructed items based on existing items and suggestions from experts and informants. Informants of subjects (n = 206) who visited the Alzheimer Center of the VU University Medical Center completed the questionnaire. Factor structure was investigated using classical exploratory factor analysis and item response theory. We assessed test-retest reliability in 73 informants using weighted κ values., Results: The questionnaire consisted of 75 items and was computerized to enhance ease of administration. Exploratory factor analysis supported a single-factor model, with 48.3% of the variance being explained by the first factor. We removed five items, as they did not fit the model. High internal consistency was demonstrated. Test-retest reliability showed that the majority of items (87.9%) had substantial-to-almost perfect κ values., Conclusion: The Amsterdam IADL Questionnaire (Amsterdam IADL questionnaire is a registered trademark of Alzheimer Center VU University Medical Center, Amsterdam, The Netherlands) is a 70-item informant-based computerized questionnaire aimed at detecting early dementia and early-onset dementia. Initial results show that this questionnaire is a promising new tool., (Copyright © 2012 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.)
- Published
- 2012
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47. A comparative study on three analytical methods for the determination of the neurotoxin BMAA in cyanobacteria.
- Author
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Faassen EJ, Gillissen F, and Lürling M
- Subjects
- Cyanobacteria Toxins, Reproducibility of Results, Sensitivity and Specificity, Amino Acids, Diamino analysis, Chromatography, High Pressure Liquid, Cyanobacteria chemistry, Neurotoxins analysis, Tandem Mass Spectrometry
- Abstract
The cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) has been considered a serious health threat because of its putative role in multiple neurodegenerative diseases. First reports on BMAA concentrations in cyanobacteria were alarming: nearly all cyanobacteria were assumed to contain high BMAA concentrations, implying ubiquitous exposure. Recent studies however question this presence of high BMAA concentrations in cyanobacteria. To assess the real risk of BMAA to human health, this discrepancy must be resolved. We therefore tested whether the differences found could be caused by the analytical methods used in different studies. Eight cyanobacterial samples and two control samples were analyzed by three commonly used methods: HPLC-FLD analysis and LC-MS/MS analysis of both derivatized and underivatized samples. In line with published results, HPLC-FLD detected relatively high BMAA concentrations in some cyanobacterial samples, while both LC-MS/MS methods only detected BMAA in the positive control (cycad seed sarcotesta). Because we could eliminate the use of different samples and treatments as causal factors, we demonstrate that the observed differences were caused by the analytical methods. We conclude that HPLC-FLD overestimated BMAA concentrations in some cyanobacterial samples due to its low selectivity and propose that BMAA might be present in (some) cyanobacteria, but in the low µg/g or ng/g range instead of the high µg/g range as sometimes reported before. We therefore recommend to use only selective and sensitive analytical methods like LC-MS/MS for BMAA analysis. Although possibly present in low concentrations in cyanobacteria, BMAA can still form a health risk. Recent evidence on BMAA accumulation in aquatic food chains suggests human exposure through consumption of fish and shellfish which expectedly exceeds exposure through cyanobacteria.
- Published
- 2012
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48. Impacts of manipulated regime shifts in shallow lake model ecosystems on the fate of hydrophobic organic compounds.
- Author
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Roessink I, Moermond CT, Gillissen F, and Koelmans AA
- Subjects
- Animals, Hydrophobic and Hydrophilic Interactions, Invertebrates metabolism, Phytoplankton metabolism, Polychlorinated Biphenyls analysis, Polychlorinated Biphenyls metabolism, Polycyclic Aromatic Hydrocarbons analysis, Polycyclic Aromatic Hydrocarbons metabolism, Ecosystem, Water Pollutants, Chemical analysis, Water Pollutants, Chemical metabolism
- Abstract
Regime shifts in shallow lakes may significantly affect partitioning of sediment-bound hydrophobic organic chemicals (HOCs) such as polychlorobiphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH). In replicated experimental model ecosystems mimicking the alternative stable states 'macrophyte-dominated' and 'suspended solid - phytoplankton dominated', we tested the effects of macrophytes and benthivorous fish presence on mass distribution and bioaccumulation of hexachlorobenzene, PCBs and PAHs. HOC mass distributions and lipid-normalized concentrations in sediment (Soxhlet- and 6-h Tenax-extractable), suspended solids, macrophytes, periphyton, algae, zooplankton, invertebrates and carp revealed that mobile, i.e. less hydrophobic or less aged HOCs were more susceptible to ecological changes than their sequestered native counterparts. Macrophytes were capable of depleting considerable percentages of the bioavailable, fast desorbing HOC fractions in the sediment upper (bioactive) layer, but did not have a significant diluting effect on lipid-normalized HOC concentrations in carp. Carp structured invertebrate communities through predation and stimulated partitioning of HOCs to other system compartments by resuspending the sediment. These results show that shifts in ecosystem structure have clear effects on fate, risks and natural attenuation of sediment-bound organic contaminants., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
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49. A kinetic approach to evaluate the association of acid volatile sulfide and simultaneously extracted metals in aquatic sediments.
- Author
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Poot A, Meerman E, Gillissen F, and Koelmans AA
- Subjects
- Acids chemistry, Kinetics, Metals, Heavy isolation & purification, Time Factors, Volatilization, Water Pollutants, Chemical isolation & purification, Geologic Sediments chemistry, Metals, Heavy analysis, Sulfides analysis, Sulfides chemistry, Water Pollutants, Chemical analysis
- Abstract
The acid volatile sulfide (AVS) and simultaneously extracted metals (SigmaSEM) method is widely used for evaluating potential bioavailability of heavy metals in soil and sediment. It is also criticized, because the requirement that AVS and SEM metals (i.e., Cd, Cu, Ni, Pb, and Zn) are associated in the same phase is not always met. Here, we propose a dissolution-kinetics-based approach to assess whether AVS and SigmaSEM originate from the same phase, as a prescreening tool for SigmaSEM-AVS-based risk assessment or site characterization. Acid volatile sulfide and SEM metals from the same phase are assumed to yield equal dissolution rates. Therefore, dissolution rates for AVS and SEM metals were measured using a modified purge-and-trap method. Results were interpreted in terms of a shrinking particle model and a first-order model, which performed equally well. Of the SEM metals, only Cu showed reaction kinetics similar to those of AVS. Extraction of Fe and SEM-Zn (which constituted more than 90% of SigmaSEM) was much faster than AVS and did not fit to the models. This suggests that they are not associated with AVS but also that AVS is probably not present as sulfide minerals. These data illustrate that the SigmaSEM-AVS risk assessment concept would not be applicable for the studied sediments.
- Published
- 2009
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50. Determination of the neurotoxins BMAA (beta-N-methylamino-L-alanine) and DAB (alpha-,gamma-diaminobutyric acid) by LC-MSMS in Dutch urban waters with cyanobacterial blooms.
- Author
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Faassen EJ, Gillissen F, Zweers HA, and Lürling M
- Subjects
- Animals, Chromatography, High Pressure Liquid, Cyanobacteria Toxins, Netherlands, Spectrometry, Mass, Electrospray Ionization, Water Microbiology, Amino Acids, Diamino analysis, Cyanobacteria chemistry, Neurotoxins analysis, Water analysis, gamma-Aminobutyric Acid analysis
- Abstract
We aimed to determine concentrations of the neurotoxic amino acids beta-N-methylamino-L-alanine (BMAA) and alpha-,gamma-diaminobutyric acid (DAB) in mixed species scum material from Dutch urban waters that suffer from cyanobacterial blooms. BMAA and DAB were analysed in scum material without derivatization by LC-MSMS (liquid chromatography coupled to tandem mass spectrometry) using hydrophilic interaction chromatography (HILIC). Our method showed high selectivity, good recovery of added compounds after sample extraction (86% for BMAA and 85% for DAB), acceptable recovery after sample hydrolysation (70% for BMAA and 56% for DAB) and acceptable precision. BMAA and DAB could be detected at an injected amount of 0.34 pmol. Free BMAA was detected in nine of the 21 sampled locations with a maximum concentration of 42 microg/g DW. Free DAB was detected in two locations with a maximum concentration of 4 microg/g DW. No protein-associated forms were detected. This study is the first to detect underivatized BMAA in cyanobacterial scum material using LC-MSMS. Ubiquity of BMAA in cyanobacteria scums of Dutch urban waters could not be confirmed, where BMAA and DAB concentrations were relatively low; however, co-occurrence with other cyanobacterial neurotoxins might pose a serious health risk including chronic effects from low-level doses.
- Published
- 2009
- Full Text
- View/download PDF
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