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| 2. |
- Balogh, Johanna, et al.
(författare)
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Deletion of a lectin gene does not affect the phenotype of the nematode-trapping fungus Arthrobotrys oligospora
- 2003
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Ingår i: Fungal Genetics and Biology. - 1087-1845. ; 39:2, s. 128-135
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Tidskriftsartikel (refereegranskat)abstract
- A number of filamentous fungi are known to produce high levels of saline-soluble and low-molecular-mass lectins. The function of these proteins are not clear but it has been proposed that they are involved in storage of nutrients, development, recognition of other organisms, and defense reactions. A gene encoding such a lectin (AOL) was deleted in the nematode-trapping fungus Arthrobotrys oligospora by homologous recombination. The deletion mutants did not express any hemagglutinating activity or protein cross-reacting with AOL antibodies. There were no significant differences between the DeltaAOL and wild-type strains in spore (conidia) germination, saprophytic growth, and pathogenicity. Furthermore, there was no significant difference in the growth and reproduction of collembolan feeding on the various strains of A. oligospora. Thus either the previous proposed functions of AOL are not correct, or the fungus can compensate for the absence of the lectin by expressing other proteins with similar function(s) as AOL. (C) 2003 Published by Elsevier Science (USA).
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| 3. |
- Bunzli, Samantha, et al.
(författare)
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Placebo Surgery Controlled Trials : Do They Achieve What They Set Out To Do? A Systematic Review
- 2021
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Ingår i: Annals of Surgery. - 1528-1140. ; 273:6, s. 1102-1107
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To explore whether placebo surgery controlled trials achieve what they set out to do by investigating discrepancy between projected and actual design aspects of trials identified through systematic review methods. SUMMARY BACKGROUND: Interest in placebo surgery controlled trials is growing in response to concerns regarding unnecessary surgery and the societal cost of low-value healthcare. As questions about the justifiability of using placebo controls in surgery have been addressed, attention is now being paid to more practical concerns. METHODS: Six databases were searched from inception - May 2020 (MEDLINE, Embase, Emcare, APA PsycInfo, CINAHL, Cochrane Library). Placebo surgery controlled trials with a published protocol were included. Three authors extracted "projected" design aspects from protocols and "actual" design aspects from main findings papers. Absolute and relative difference between projected and actual design aspects were presented for each trial. Trials were grouped according to whether they met their target sample size ("completed") and were concluded in a timely fashion. Pairs of authors assessed risk of bias. RESULTS: Of 24 trials with data available to analyse; 3 were completed and concluded within target timeframe; 10 were completed and concluded outside the target timeline; 4 were completed without clear target timeframes; 2 were incomplete and concluded within the target framework; 5 were incomplete and concluded outside the target timeline. Trials which reached the recruitment target underestimated trial duration by 88% and number of recruitment sites by 87%. CONCLUSIONS: Trialists need to factor additional time and sites into future placebo surgery controlled trials. A robust reporting framework of projected and actual trial design is imperative for trialists to learn from their predecessors. REVIEW REGISTRATION: PROSPERO (CRD42019133296).
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| 4. |
- Karaba Bäckström, Martin, et al.
(författare)
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Occupational therapy gender imbalance; revisiting a lingering issue
- 2023
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Ingår i: Scandinavian Journal of Occupational Therapy. - : Taylor & Francis. - 1103-8128 .- 1651-2014. ; 30:7, s. 1113-1121
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recently, it has been suggested that gender disparity in Occupational Therapy has to do with segregated gendered job norms that position female dominated professions as a 'step down' for many males. Interestingly, this suggestion was not underpinned by experiences of males in the profession.Aims and methods: Thirteen male Occupational Therapists with a variety of backgrounds were invited to this Round Table research, focussing on the broader issue of the existing gender imbalance in Occupational Therapy.Results: Two themes emerged: 'The core values of the profession', and 'Broadening the scope of the profession'; none of them suggesting that male/female imbalance was necessarily the most pressing issue.Conclusions: A gender-unrelated approach to everyday problem-solving was put forward to achieve increased diversity in Occupational Therapists' backgrounds, better reflecting the people they serve. By broadening the scope and the way the profession is presented, and encouraging innovative and more entrepreneurially driven approaches, diversity in the workforce could be further facilitated. These findings are discussed within the context of 'The mutual constitution of cultures and selves' model.Significance: Diversity in the Occupational therapy workforce could be further facilitated with a shift in focus away from the male/female perspective to an intersectional approach.
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| 5. |
- Kirilly, Eszter, et al.
(författare)
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Decrease in REM latency and changes in sleep quality parallel serotonergic damage and recovery after MDMA: a longitudinal study over 180 days
- 2008
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Ingår i: International Journal of Neuropsychopharmacology. - 1469-5111. ; 11:6, s. 795-809
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Tidskriftsartikel (refereegranskat)abstract
- The recreational drug ecstasy [3,4-methylenedioxymethamphetamine (MDMA)], has been found to selectively damage brain serotonin neurons in experimental animals, and probably in human MDMA users, but detailed morphometric analyses and parallel functional measures during damage and recovery are missing. Since there is evidence that serotonin regulates sleep, we have compared serotonergic markers parallel with detailed analysis of sleep patterns at three time-points within 180 d after a single dose of 15 mg/kg MDMA in male Dark Agouti rats. At 7 d and 21 d after MDMA treatment, significant (30-40%), widespread reductions in serotonin transporter (5-HTT) density were detected in the cerebral cortex, hippocampus, most parts of the hypothalamus, and some of the brainstem nuclei. With the exception of the hippocampus, general recovery was observed in the brain 180 d after treatment. Transient increases followed by decreases were detected in 5-HTT mRNA expression of dorsal and median raphe nuclei at 7 d and 21 d after the treatment. Significant reductions in rapid eye movement (REM) sleep latency, increases in delta power spectra in non-rapid eye movement sleep and increased fragmentation of sleep were also detected, but all these alterations disappeared by the 180th day. The present data provide evidence for long-term, albeit, except for the hippocampus, transient changes in the terminal and cellular regions of the serotonergic system after this drug. Reduced REM latency and increased sleep fragmentation are the most characteristic alterations of sleep consistently described in depression using EEG sleep polygraphy.
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| 6. |
- Schilling, Chris, et al.
(författare)
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An Economic Model for Estimating Trial Costs with an Application to Placebo Surgery Trials
- 2023
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Ingår i: Applied Health Economics and Health Policy. - : Springer Science and Business Media LLC. - 1175-5652 .- 1179-1896. ; 21:2, s. 263-273
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Tidskriftsartikel (refereegranskat)abstract
- Background and Objective: Waste in clinical trials remains rife. We developed an economic model to predict the cost of trials based on input costs, duration, power, number of sites, recruitment eligibility and consenting rates. Methods: We parameterised the model for three proxy placebo-controlled surgical trials using data from a systematic review, a bespoke cost survey, and from the literature. We used the model to compare target and actual trial performance for (i) a trial that was completed on time but with more sites, (ii) a trial that completed after a time extension, and (iii) an incomplete trial. Results: Successful trials more accurately anticipated the true recruitment rate that they achieved and those that overestimated this were most likely to fail. The costs of overestimating recruitment rates were dramatic: all proxy trials had significantly higher costs than planned, with additional funding of at least AUD$600,000 (50% above budget) required for trials that completed after adding more sites or more time, and over AUD$2 million (260% above budget) for incomplete trials. Conclusions: This model shows the trade-offs between time and cost, or both, when recruitment is lower than anticipated. Greater consideration is needed to improve trial planning, reviewing, and funding of these trials to avoid costly overruns and incomplete trials.
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| 7. |
- Shadbolt, Cade, et al.
(författare)
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Analysis of Rates of Completion, Delays, and Participant Recruitment in Randomized Clinical Trials in Surgery
- 2023
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Ingår i: JAMA Network Open. - : American Medical Association (AMA). - 2574-3805. ; 6, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE: Discontinuation and nonpublication are established sources of avoidable waste among surgical trials, but rates of delayed completion and recruiting shortfalls remain unclear.OBJECTIVES: To examine the rate of delayed completion, incomplete enrollment, and discontinuation among randomized clinical trials in surgical populations and the duration of delays and extent of recruiting shortfalls among these trials.DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study examined randomized clinical trials in surgical populations registered on ClinicalTrials.gov between January 1, 2010, and December 31, 2014. Analysis was conducted between October 27, 2021, and June 30, 2022.MAIN OUTCOMES AND MEASURES: The main outcomes were the percentages of trials completed on time or with full enrollment. Delays and recruiting shortfalls were identified by comparing projected enrollment and study timeframes prespecified at the time of registration with the actual study duration and enrollment reported on completion or discontinuation. Absolute and relative differences between planned and actual trial conduct were presented for discontinued trials and those completed with delays or recruiting shortfalls.RESULTS: In total, 2542 randomized clinical trials in surgical populations were included in the study sample, of which 370 (14.6%; 95% CI, 13.2%-15.9%) were completed both on time and with full enrollment. Approximately 1 in 5 trials (20.4%; 95% CI, 18.9%-22.0%) were completed within their planned timeframe, and 1166 trials (45.9%; 95% CI, 43.9%-47.8%) met their prespecified enrollment target. The median delay among completed trials was 12.2 months (IQR, 5.1-24.3 months) or 66.7% (IQR, 30.1%-135.8%) longer than planned. Among completed trials that did not meet their prespecified enrollment target, the median recruiting shortfall was equivalent to 31.0% (IQR, 12.7%-55.5%) of the planned study sample. A total of 546 trials (21.5%; 95% CI, 19.9%-23.1%) were discontinued. The median time to discontinuation was 26.4 months (IQR, 15.2-45.7 months), and the median recruiting shortfall among discontinued trials was equivalent to 92.7% (IQR, 65.0%-100.0%) of the trial's prespecified enrollment target.CONCLUSIONS AND RELEVANCE: This cross-sectional study found that delayed completion, recruiting shortfalls, and untimely discontinuation were common among surgical trials. These findings highlight the importance of ensuring that investigators and funders do not overestimate the feasibility of planned trials.
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| 8. |
- Sowersby, Will, et al.
(författare)
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Costly sexual ornaments coevolve with fast life-histories in killifishes
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Sexually selected ornaments constitute an important investment into reproduction, increasing current mating success, at a potential cost to survival. Theory suggests that exaggerated sexual ornaments may coevolve with the life-history trade-off between current and future reproduction, however this hypothesis has remained unexplored. Here, we determine how the size of secondary sexual traits coevolves with the pace of life-histories (slow or fast), using a clade of killifishes, where independent adaptations to ephemeral environments have resulted in substantial divergences in life-history strategy. In addition, we assess costs to swimming performance driven by enlarged, ornamental fins. We predict that killifishes with fast life-histories, which inhabit time-limited environments and prioritize current reproduction, will have a greater tendency to evolve enlarged fins, compared to killifishes with slow life-histories. Indeed, we found that species with fast life-histories had more pronounced sexual size dimorphism, with males from these species having exaggerated dorsal and anal fins, compared to species with slow life-histories. Furthermore, males from species with fast life-histories and larger ornaments exhibited lower swimming performances compared to both conspecific females, and individuals from species with slow life-histories. Our results indicate that the trade-off between current and future reproduction, can be an evolutionary driver of costly sexual ornaments.
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| 9. |
- Sowersby, Will, et al.
(författare)
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The relative effects of pace of life-history and habitat characteristics on the evolution of sexual ornaments : A comparative assessment
- 2022
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:1, s. 114-127
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Tidskriftsartikel (refereegranskat)abstract
- Selection may favor greater investment into sexual ornaments when opportunities for future reproduction are limited, for example, under high adult mortality. However, predation, a key driver of mortality, typically selects against elaborate sexual ornaments. Here, we examine the evolution of sexual ornaments in killifishes, which have marked contrasts in life-history strategy among species and inhabit environments that differ in accessibility to aquatic predators. We first assessed if the size of sexual ornaments (unpaired fins) influenced swimming performance. Second, we investigated whether the evolution of larger ornamental fins is driven primarily by the pace of life-history (investment into current vs. future reproduction) or habitat type (a proxy for predation risk). We found that larger fins negatively affected swimming performance. Further, males from species inhabiting ephemeral habitats, with lower predation risk, had larger fins and greater sexual dimorphism in fin size, compared to males from more accessible permanent habitats. We show that enlarged ornamental fins, which impair locomotion, evolve more frequently in environments that are less accessible to predators, without clear associations to life-history strategy. Our results provide a rare link between the evolution of sexual ornaments, effects on locomotion performance, and natural selection on ornament size potentially through habitat differences in predation risk.
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