157 research outputs found

    Turnover of dimethylsulfoniopropionate and dimethylsulfide in the marine environment:A mesocosm experiment

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    The production of dimethylsulfoniopropionate (DMSP) by marine phytoplankton and the fate of the produced DMSP and dimethylsulfide (DMS) were studied in 4 pelagic mesocosms during an algal bloom over a period of 1 mo. Bacterial numbers, concentrations of particulate and dissolved DMSP, DMS, and chlorophyll a were monitored, as well as the turnover rates of DMS and DMSP. Of the total amount of DMSP produced, only a fraction could be detected as DMS in the water column. DMS production in the water column did not necessarily correlate with algal senescence, but also occurred during the maximum of the algal bloom. The flux of DMS to the atmosphere played a minor role as a sink for DMS. Evidence is presented that shows bacterial consumption to be a major sink for DMS, under conditions of both high and low DMS water concentrations. DMSP was degraded either via cleavage or via demethylation; the results indicate a predominant role for the latter route

    DMSP synthesis and exudation in phytoplankton:a modeling approach

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    In the marine environment, phytoplankton are the fundamental producers of dimethylsulfoniopropionate (DMSP), the precursor of the climatically active gas dimethylsulfide (DMS). DMSP is released by exudation, cell autolysis, and zooplankton grazing during phytoplankton blooms. In this study, we developed a model of phytoplankton DMSP and DMS production allowing quantification of the exudation rates of these compounds during different growth phases. The model was tested on published data from axenic cultures of Prorocentrum minimum and Phaeocystis sp.; DMSP exudation rates vary considerably between the 2 species. Model results show that P. minimum exudes around 1% d(-1) of its DMSP quota during the latent, exponential and senescent phases. This is comparable to the average exudation rate estimated from previous laboratory experiments. However, Phaeocystis sp. exudes from 3 to 11% d(-1) of its DMSP quota. For this species, DMSP exudation rates apparently show an inverse relationship with the population growth rate. The maximum DMSP exudation rate in Phaeocystis sp. is 10 times higher than previously reported DMSP or DMS exudation rates. Our results suggest that exudation may be as important as cell autolysis in the release of DMSP during Phaeocystis sp. blooms. We conclude that exudation should be incorporated in models of DMS cycling in the marine environment. Moreover, our results for Phaeocystis sp. suggest that a low and constant exudation rate, as sometimes used in models, is not suitable for all conditions

    Barriers and facilitators for the implementation of the CombiConsultation by general practitioners, pharmacists and practice nurses: a qualitative interview study

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    BACKGROUND: The CombiConsultation is a consultation with the pharmacist for patients with a chronic condition, aligned with the periodic consultation with the practice nurse or general practitioner. Implementation requires adjustments in the working methods of these healthcare providers and therefore behavioural changes. AIM: The aim of this study was to identify the barriers and facilitators that determine the behavioural changes by pharmacists, general practitioners and practice nurses required for the implementation of the CombiConsultation. METHOD: Ten community pharmacists, 5 practice nurses and 5 general practitioners were sampled from practices enrolled in the CombiConsultation study. Their views regarding the implementation of this clinical pharmacy service were explored using interviews based on the 14 domains of the Theoretical Domains Framework (TDF), which are linked to the Capability-Opportunity-Motivation-Behaviour-model. Barriers and facilitators in the domains were assessed by content analysis. RESULTS: Twelve barriers and 23 facilitators were found within 13 TDF domains with high agreement between the healthcare providers. Important facilitators for implementation were the pharmacists' expertise in pharmacotherapy (capability), access to medical data and physical proximity between professional practices (opportunity). Barriers were pharmacists' insufficient consultation- and clinical-reasoning skills (capability), insufficient staff (opportunity) and reimbursement and lack of coordination among all involved healthcare providers (motivation). CONCLUSION: All healthcare providers are motivated to implement the CombiConsultation. An existing collaborative practice, with a clear and accepted professional role of the pharmacist is essential. Training of pharmacists in consultation and clinical-reasoning skills can be beneficial, as well as arrangements on the consultation logistics, and reimbursement

    The CombiConsultation: a new concept of sequential consultation with the pharmacist and practice nurse/general practitioner for patients with a chronic condition

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    The primary health care system is generally well organized for dealing with chronic diseases, but comprehensive medication management is still a challenge. Studies suggest that pharmacists can contribute to effective and safe drug therapy by providing services like a clinical medication review (CMR). However, several factors limit the potential impact of a CMR. Therefore, we propose a new pharmaceutical care service for patients with a chronic condition: the CombiConsultation. The CombiConsultation is a medication evaluation service conducted by the (community) pharmacist and either the practice nurse or general practitioner. It consists of 3 steps: medication check, implementation and follow-up. The pharmacist primarily focusses on setting treatment goals for 1 or 2 drug-related problems in relation to a specific chronic condition. In this manuscript we describe the process and characteristics of the CombiConsultation. We compare the CombiConsultation with the CMR and explain the choices made and the implications for implementation

    Managerial Work in a Practice-Embodying Institution - The role of calling, the virtue of constancy

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    What can be learned from a small scale study of managerial work in a highly marginal and under-researched working community? This paper uses the ‘goods-virtues-practices-institutions’ framework to examine the managerial work of owner-directors of traditional circuses. Inspired by MacIntyre’s arguments for the necessity of a narrative understanding of the virtues, interviews explored how British and Irish circus directors accounted for their working lives. A purposive sample was used to select subjects who had owned and managed traditional touring circuses for at least 15 years, a period in which the economic and reputational fortunes of traditional circuses have suffered badly. This sample enabled the research to examine the self-understanding of people who had, at least on the face of it, exhibited the virtue of constancy. The research contributes to our understanding of the role of the virtues in organizations by presenting evidence of an intimate relationship between the virtue of constancy and a ‘calling’ work orientation. This enhances our understanding of the virtues that are required if management is exercised as a domain-related practice

    Cost-utility and cost-effectiveness analysis of a clinical medication review focused on personal goals in older persons with polypharmacy compared to usual care: Economic evaluation of the DREAMeR study

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    AIMS: The ageing society may lead to increasing healthcare expenditure. A clinical medication review (CMR) could potentially reduce costs. The aim of this study is to perform a cost-utility and cost-effectiveness analysis from a societal perspective of a patient-centred CMR. METHODS: A trial-based cost-utility and cost-effectiveness analysis was performed as part of the DREAMeR study, a pragmatic controlled trial that randomised patients aged ≥70 years using at least seven drugs to either CMR or usual care. Over six months, healthcare consumption and drug use were collected to estimate costs, and effects were collected in terms of quality-adjusted life years (QALYs) measured with EQ-5D-5 L and EQ-VAS and as reduced health-related complaints with impact on patients' daily lives. RESULTS: The total mean costs per patient (n = 588) over six months were €4,189 ± 6,596 for the control group (n = 294) and €4,008 ± 6,678 for the intervention group (n = 294), including estimated intervention costs of €199 ± 67, which resulted in a mean incremental total cost savings of €181 for the intervention group compared to the control group. Compared to the control group, for the intervention group, the mean incremental QALYs over six months were: -0.00217 measured with EQ-5D and 0.003 measured with EQ-VAS. The incremental effect of reduced health-related complaints with impact was -0.34. There was a likelihood of >90% that the intervention was cost-saving. CONCLUSIONS: The benefits of a patient-centred CMR were inconsistent with no benefits on HR-QoL measured with EQ-5D-5 L and small benefits on HR-QoL measured with EQ-VAS and health-related complaints with impact on patients' daily lives. Additionally, a CMR could potentially be cost saving from a societal perspective

    Phase 3 Randomized Trial of Prophylactic Cranial Irradiation With or Without Hippocampus Avoidance in SCLC (NCT01780675)

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    Introduction: To compare neurocognitive functioning in patients with SCLC who received prophylactic cranial irradiation (PCI) with or without hippocampus avoidance (HA). Methods: In a multicenter, randomized phase 3 trial (NCT01780675), patients with SCLC were randomized to standard PCI or HA-PCI of 25 Gy in 10 fractions. Neuropsychological tests were performed at baseline and 4, 8, 12, 18, and 24 months after PCI. The primary end point was total recall on the Hopkins Verbal Learning Test-Revised at 4 months; a decline of at least five points from baseline was considered a failure. Secondary end points included other cognitive outcomes, evaluation of the incidence, location of brain metastases, and overall survival. Results: From April 2013 to March 2018, a total of 168 patients were randomized. The median follow-up time was 26.6 months. In both treatment arms, 70% of the patients had limited disease and baseline characteristics were well balanced. Decline on the Hopkins Verbal Learning Test-Revised total recall score at 4 months was not significantly different between the arms: 29% of patients on PCI and 28% of patients on HA-PCI dropped greater than or equal to five points (p = 1.000). Performance on other cognitive tests measuring memory, executive function, attention, motor function, and processing speed did not change significantly different over time between the groups. The overall survival was not significantly different (p = 0.43). The cumulative incidence of brain metastases at 2 years was 20% (95% confidence interval: 12%-29%) for the PCI arm and 16% (95% confidence interval: 7%-24%) for the HA-PCI arm. Conclusions: This randomized phase 3 trial did not find a lower probability of cognitive decline in patients with SCLC receiving HA-PCI compared with conventional PCI. No increase in brain metastases at 2 years was observed in the HA-PCI arm. (C) 2021 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved
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