142 research outputs found

    Post-copulatory opportunities for sperm competition and cryptic female choice provide no offspring fitness benefits in externally fertilizing salmon

    Get PDF
    There is increasing evidence that females can somehow improve their offspring fitness by mating with multiple males, but we understand little about the exact stage(s) at which such benefits are gained. Here, we measure whether offspring fitness is influenced by mechanisms operating solely between sperm and egg. Using externally-fertilising and polyandrous Atlantic salmon (Salmo salar), we employed split-clutch and split-ejaculate in vitro fertilisation experiments to generate offspring using designs that either denied or applied opportunities for sperm competition and cryptic female choice. Following fertilisations, we measured 140 days of offspring fitness after hatch, through growth and survival in hatchery and near-natural conditions. Despite an average composite mortality of 61%, offspring fitness at every life stage was near-identical between groups fertilised under the absence versus presence of opportunities for sperm competition and cryptic female choice. Of the 21,551 and 21,771 eggs from 24 females fertilised under monandrous versus polyandrous conditions, 68% versus 67.8% survived to the 100-day juvenile stage; sub-samples showed similar hatching success (73.1% versus 74.3%), had similar survival over 40 days in near-natural streams (57.3% versus 56.2%), and grew at similar rates throughout. We therefore found no evidence that gamete-specific interactions allow offspring fitness benefits when polyandrous fertilisation conditions provide opportunities for sperm competition and cryptic female choice

    Detection of Rift Valley Fever Virus RNA in Formalin-Fixed Mosquitoes by In Situ Hybridization (RNAscope®).

    Get PDF
    Rift Valley fever virus (RVFV) causes a zoonotic mosquito-borne haemorrhagic disease that emerges to produce rapid large-scale outbreaks in livestock within sub-Saharan Africa. A range of mosquito species in Africa have been shown to transmit RVFV, and recent studies have assessed whether temperate mosquito species are also capable of transmission. In order to support vector competence studies, the ability to visualize virus localization in mosquito cells and tissue would enhance the understanding of the infection process within the mosquito body. Here, the application of in situ hybridization utilizing RNAscope® to detect RVFV infection within the mosquito species, Culex pipiens, derived from the United Kingdom was demonstrated. Extensive RVFV replication was detected in many tissues of the mosquito with the notable exception of the interior of ovarian follicles

    Mimicking superinfection exclusion disrupts alphavirus infection and transmission in the yellow fever mosquito Aedes aegypti

    Get PDF
    Multiple viruses, including pathogenic viruses, bacteriophages, and even plant viruses, cause a phenomenon termed superinfection exclusion whereby a currently infected cell is resistant to secondary infection by the same or a closely related virus. In alphaviruses, this process is thought to be mediated, at least in part, by the viral protease (nsP2) which is responsible for processing the nonstructural polyproteins (P123 and P1234) into individual proteins (nsP1–nsP4), forming the viral replication complex. Taking a synthetic biology approach, we mimicked this naturally occurring phenomenon by generating a superinfection exclusion-like state in Aedes aegypti mosquitoes, rendering them refractory to alphavirus infection. By artificially expressing Sindbis virus (SINV) and chikungunya virus (CHIKV) nsP2 in mosquito cells and transgenic mosquitoes, we demonstrated a reduction in both SINV and CHIKV viral replication rates in cells following viral infection as well as reduced infection prevalence, viral titers, and transmission potential in mosquitoes.</p

    Estimating the cost‐effectiveness of intermittently scanned continuous glucose monitoring in adults with type 1 diabetes in England

    Get PDF
    We previously showed that intermittently scanned continuous glucose monitoring (isCGM) reduces HbA1c at 24 weeks compared with self-monitoring of blood glucose with finger pricking (SMBG) in adults with type 1 diabetes and high HbA1c levels (58-97 mmol/mol [7.5%-11%]). We aim to assess the economic impact of isCGM compared with SMBG. Participant-level baseline and follow-up health status (EQ-5D-5L) and within-trial healthcare resource-use data were collected. Quality-adjusted life-years (QALYs) were derived at 24 weeks, adjusting for baseline EQ-5D-5L. Participant-level costs were generated. Using the IQVIA CORE Diabetes Model, economic analysis was performed from the National Health Service perspective over a lifetime horizon, discounted at 3.5%. Within-trial EQ-5D-5L showed non-significant adjusted incremental QALY gain of 0.006 (95% CI: -0.007 to 0.019) for isCGM compared with SMBG and an adjusted cost increase of £548 (95% CI: 381-714) per participant. The lifetime projected incremental cost (95% CI) of isCGM was £1954 (-5108 to 8904) with an incremental QALY (95% CI) gain of 0.436 (0.195-0.652) resulting in an incremental cost-per-QALY of £4477. In all subgroups, isCGM had an incremental cost-per-QALY better than £20,000 compared with SMBG; for people with baseline HbA1c >75 mmol/mol (9.0%), it was cost-saving. Sensitivity analysis suggested that isCGM remains cost-effective if its effectiveness lasts for at least 7 years. While isCGM is associated with increased short-term costs, compared with SMBG, its benefits in lowering HbA1c will lead to sufficient long-term health-gains and cost-savings to justify costs, so long as the effect lasts into the medium term. [Abstract copyright: © 2023 The Authors. Diabetic Medicine published by John Wiley & Sons Ltd on behalf of Diabetes UK.

    Adam Smith’s Green Thumb and Malthus’ Three Horsemen: Cautionary tales from classical political economy

    Get PDF
    This essay identifies a contradiction between the flourishing interest in the environmental economics of the classical period and a lack of critical parsing of the works of its leading representatives. Its focus is the work of Adam Smith and Thomas Malthus. It offers a critical analysis of their contribution to environmental thought and surveys the work of their contemporary devotees. It scrutinizes Smith's contribution to what Karl Polanyi termed the "economistic fallacy," as well as his defenses of class hierarchy, the "growth imperative" and consumerism. It subjects to critical appraisal Malthus's enthusiasm for private property and the market system, and his opposition to market regulation. While Malthus's principal attraction to ecological economists lies in his having allegedly broadened the scope of economics, and in his narrative of scarcity, this article shows that he, in fact, narrowed the scope of the discipline and conceptualized scarcity in a reified and pseudo-scientific way

    A prospective study of MRI biomarkers in the brain and lower limb muscles for prediction of lower limb motor recovery following stroke

    Get PDF
    The aim of this prospective observational longitudinal study was to explore and decipher the predictive value of prospective MRI biomarkers in the brain and lower limb muscles for 3-month lower limb motor recovery following stroke. In the brain, we measured the integrity of the corticospinal tract (fractional anisotropy/"FA"). In the muscles, we measured volume, fatty replacement (fat fraction analysis and proton spectroscopy) and oedema. Measurements were taken at two time points: (1) within 4 weeks of stroke (baseline measurement, clinical and imaging) and (2) 3 months following stroke (follow up measurement, clinical only). Clinical measurements consisted of assessments of functional ability and strength (Fugl-Meyer score, motor NIHSS, Functional Ambulation Category/"FAC", and muscle dynamometry). Twenty-three patients completed imaging and clinical assessments at baseline and follow-up; five patients had partial imaging assessment. The results provided some evidence that damage to the corticospinal tract would result in less motor recovery: recovery of the Fugl-Meyer score and dynamometric ankle plantarflexion, ankle dorsiflexion, and knee extension correlated positively and significantly with fractional anisotropy (0.406-0.457; p = 0.034-p = 0.016). However, fractional anisotropy demonstrated a negative correlation with recovery of the Functional Ambulation Category (-0.359, p = 0.046). For the muscle imaging, significant inverse correlation was observed between vastus lateralis fat fraction vs. NIHSS recovery (-0.401, p = 0.04), and a strong positive correlation was observed between ratio of intra- to extra-myocellular lipid concentrations and the recovery of knee flexion (0.709, p = 0.007). This study supports previous literature indicating a positive correlation between the integrity of the corticospinal tract and motor recovery post-stroke, expanding the limited available literature describing this relationship specifically for the lower limb. However, recovery of functional ambulation behaved differently to other clinical recovery markers by demonstrating an inverse relationship with corticospinal tract integrity. The study also introduces some muscle imaging biomarkers as potentially valuable in the prediction of 3-month lower limb motor recovery following stroke

    Exploring the impact of a housing support service on hospital discharge: a mixed-methods process evaluation in two UK hospital trusts

    Get PDF
    Delayed discharge from hospital is a global healthcare problem with negative impacts on patient outcomes and the wider health system. Delays to discharge can arise when a patient remains in hospital even when they are medically fit due to nonmedical reasons such as a lack of appropriate housing or social care. However, whilst several nonmedical interventions have been developed to facilitate timely hospital discharge, there remains a lack of evidence on their impact. This study reports on findings from a mixed-methods process evaluation of a newly integrated housing and health service in two United Kingdom- (UK-) based hospitals (one mental health hospital and one general hospital). The service involved housing support coordinators (HSCs) being based within hospitals and supporting inpatients with their housing-related needs. We employed qualitative interviews with service users and hospital/housing staff (N = 16) and routine data analysis (n = 488) to understand the impact of the service and any challenges to service delivery. Service users faced different housing barriers, for example: 28.3% experienced homelessness (n = 136) whilst 80 (16.4%) faced challenges with their accommodation no longer meeting their physical needs. Service users received support for a variety of issues such as assistance with medical priority applications, support to apply for social housing, and referral to other support services. Healthcare professionals at all levels credit the service for improving hospital discharge processes and reducing stress on clinical staff, enabling them to concentrate more effectively on clinical tasks. Key to success is experienced housing staff providing patient-centred support, being integrated within a multidisciplinary team with management and oversight from the health service, and the availability of appropriate housing stock and wider services to support people after discharge. Our findings indicate that other hospitals may benefit from implementing similar housing and health integrated services

    Smoking cessation support by text message during pregnancy: a qualitative study of views and experiences of the MiQuit intervention

    Get PDF
    Introduction: SMS text messaging is increasingly used for delivering smoking cessation support and pilot studies suggest this may also be useful in pregnancy. This study explores the views of women who received a tailored text messaging cessation intervention (MiQuit) during pregnancy, focusing on acceptability, perceived impact, and suggestions for improvements. Methods: Semi-structured interviews were undertaken with 15 purposively sampled women who had received the MiQuit intervention during pregnancy as part of a randomized controlled trial. Data were analyzed thematically. Results: Three main themes were identified: “impact”, “approach,” and “optimization.” Participants described an immediate, yet often short-lived, impact from the texts that distracted and delayed them from smoking and they perceived that texts focusing on the development of and risk to the baby generated more enduring emotional impacts. Most women found receiving support by text preferable to face-to-face cessation support, with participants citing the greater regularity, convenience, and non-judgmental style as particular advantages. Participants would have preferred a longer support program with increased tailoring, greater customization of text timings and consideration of cutting down as an alternative/precursor to quitting. Conclusion: Pregnancy-specific cessation support by text message was well received and participants considered the support increased their motivation to stop smoking. The focus on the developing baby, the regularity of contact and the provision of gentle, encouraging messages were highlighted as particularly important elements of the program. Implications: This study adds further evidence to the acceptability and perceived positive impact of text-messaging programs in aiding smoking cessation in pregnancy. The findings indicate that for some women, this type of support is preferable to face-to-face methods and could be utilized by health professionals, either in addition to current methods or as an alternative. This study is also relevant to researchers developing health-related text programs to consider participants’ desire for greater tailoring. Further research is required into adapting and continuing text support for women postpartum

    Smoking Is Associated with, but Does Not Cause, Depressed Mood in Pregnancy – A Mendelian Randomization Study

    Get PDF
    Smokers have a higher prevalence of major depressive episodes and depressive symptoms than the general population, but whether this association is causal, or is due to confounding or reverse causation is uncertain because of the problems inherent in some epidemiological studies. Mendelian randomization, in which a genetic variant is used as a surrogate for measuring exposure, is an approach which may be used to better understand this association. We investigated the rs1051730 single nucleotide polymorphism in the nicotine acetylcholine receptor gene cluster (CHRNA5-CHRNA3-CHRNB4), associated with smoking phenotypes, to determine whether women who continued to smoke were also more likely to report a low mood during pregnancy. We found among women who smoked pre-pregnancy, those with the 1051730 T allele smoked more and were less likely to quit smoking during pregnancy, but were also less likely to report high levels of depressed mood at 18 weeks of pregnancy (per allele OR = 0.84, 95%CI 0.72 to 0.99, p = 0.034). The association between genotype and depressed mood was limited to women who were smokers prior to pregnancy, with weak evidence of an interaction between smoking status and genotype (p = 0.07). Our results do not support a causal role of smoking on depressed mood, but are consistent with a self-medication hypothesis, whereby smoking is used to alleviate symptoms of depression. A replication study using multiple genetic variants which influence smoking via different pathways is required to confirm these findings and provide evidence that the genetic variant is reflecting the effect of quitting smoking on depressed mood, and is not directly affecting mood
    corecore