3,009 research outputs found
Viability of calanoid copepod eggs from intertidal sediments: A comparison of three estuaries
Calanoid copepod nauplii hatched from intertidal sediment samples from 3 British estuaries, the Exe, the Humber and the Mersey. The Exe Estuary is exposed to low levels of urban and agricultural pollution but the Humber and Mersey are subject to more extensive urban and industrial pollution. Samples were taken from the Humber and the Exe in April and November 1995 and from the Mersey and the Exe in June and October 1995. The concentrations of polycyclic aromatic hydrocarbons (PAH) in the sediments were measured as an index of pollution. The PAH concentrations in sediment were lowest in the Exe (mean 200 mu g/g dry weight in the Humber and some >300 mu g/g dry weight in the Mersey. Many more nauplii hatched from incubated sediments from the Exe than from the more polluted estuaries in April, June and November but larger numbers of nauplii hatched from the samples from the Mersey than from the Exe in October. Eggs were extracted from the samples taken in October and November and incubated; 92% of those from the Exe, 48% of those from the Humber and 14% of those from the Mersey hatched. This is consistent with reduction in viability of eggs with increased pollution. The viability of copepod eggs from sediments appears to have potential as a technique for in situ bioassay of fine sediments
Multi-scale interaction of flow and the artery wall
We discuss, from the perspective of basic science, the physical and biological processes which underlie atherosclerotic (plaque) initiation at the vascular endothelium, identifying their widely separated spatial and temporal scales which participate. We draw on current, related models of vessel wall evolution, paying particular attention to the role of flow, and proceed to propose, then validate (in practical, qualitative terms, at least) a multiply coupled, multi-scale modeling strategy, which, eventually, aims at a quantitative, patient-specific understanding of the coupling between the flow and the endothelial state
Academic achievement at ages 11 and 16 in children born with congenital anomalies in England: A multi-registry linked cohort study
\ua9 2024 The Authors. Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd. Background: Children born with major congenital anomalies (CAs) have lower academic achievement compared with their peers, but the existing evidence is restricted to a number of specific CAs. Objectives: To investigate academic outcomes at ages 11 and 16 in children with major isolated structural CAs and children with Down or Turner syndromes. Methods: This population-based cohort study linked data on approximately 11,000 school-aged children born with major CAs in 1994–2004 registered by four regional CA registries in England with education data from the National Pupil Database (NPD). The comparison group was a random sample of children without major CAs from the background population recorded in the NPD that were frequency matched (5:1) to children with CAs by birth year, sex and geographical area. Results: Overall, 71.9%, 73.0% and 80.9% of children with isolated structural CAs achieved the expected attainment level at age 11 compared to 78.3%, 80.6% and 86.7% of the comparison group in English language, Mathematics and Science, respectively. Children with nervous system CAs as a whole had the lowest proportion who achieved the expected attainment at age 11. At age 16, 46.9% of children with CAs achieved the expected level compared to 52.5% of their peers. Major CAs were associated with being up to 9% (95% confidence interval [CI] 8%, 11%) and 12% (95% CI 9%, 14%) less likely to achieve expected levels at ages 11 and 16, respectively, after adjustment for socioeconomic deprivation. Conclusions: Although many children with isolated CAs achieved the expected academic level at ages 11 and 16, they were at higher risk of underachievement compared to their peers. These stark yet cautiously encouraging results are important for counselling parents of children with specific CAs and also highlight the possible need for special education support to reduce potential academic difficulties
Access to Principal Treatment Centres and survival rates for children and young people with cancer in Yorkshire, UK
Background: Principal Treatment Centres (PTC) were established to provide age-appropriate care as well as clinical expertise for children and young people with cancer. However, little is known about the effects of specialist treatment centres on survival outcomes especially for teenagers and young adults. This population-based study aimed to describe access to PTC and the associated trends in survival for 0–24 year olds accounting for stage of disease at presentation and treatment. Methods: Patients diagnosed from 1998–2009 aged 0–24 years were extracted from the Yorkshire Specialist Register of Cancer in Children and Young People, including information on all treating hospitals, followed-up until 31st December 2014. The six commonest cancer types were included: leukaemia (n = 684), lymphoma (n = 558), CNS tumours (n = 547), germ cell tumours (n = 364), soft tissue sarcomas (n = 171) and bone tumours (n = 163). Treatment was categorised into three groups: ‘all’, ‘some’ or ‘no’ treatment received at a PTC. Treatment at PTC was examined by diagnostic group and patient characteristics. Overall survival was modelled using Cox regression adjusting for case-mix including stage, treatment and other socio-demographic and clinical characteristics. Results: Overall 72% of patients received all their treatment at PTC whilst 13% had no treatment at PTC. This differed by diagnostic group and age at diagnosis. Leukaemia patients who received no treatment at PTC had an increased risk of death which was partially explained by differences in patient case-mix (adjusted Hazard Ratio (HR) = 1.73 (95%CI 0.98–3.04)). Soft tissue sarcoma patients who had some or no treatment at PTC had better survival outcomes, which remained after adjustment for patient case-mix (adjusted HR = 0.48 (95%CI 0.23–0.99)). There were no significant differences in outcomes for other diagnostic groups (lymphoma, CNS tumours, bone tumours and germ cell tumours). For leukaemia patients survival outcomes for low risk patients receiving no treatment at PTC were similar to high risk patients who received all treatment at PTC, implying a benefit for care at the PTC. Conclusion: This study demonstrates that for leukaemia patients receiving treatment at a PTC is associated with improved survival that may compensate for a poorer prognosis presentation. However, further information on risk factors is needed for all diagnostic groups in order to fully account for differences in patient case-mix
Exploring the Free Energy Landscape: From Dynamics to Networks and Back
The knowledge of the Free Energy Landscape topology is the essential key to
understand many biochemical processes. The determination of the conformers of a
protein and their basins of attraction takes a central role for studying
molecular isomerization reactions. In this work, we present a novel framework
to unveil the features of a Free Energy Landscape answering questions such as
how many meta-stable conformers are, how the hierarchical relationship among
them is, or what the structure and kinetics of the transition paths are.
Exploring the landscape by molecular dynamics simulations, the microscopic data
of the trajectory are encoded into a Conformational Markov Network. The
structure of this graph reveals the regions of the conformational space
corresponding to the basins of attraction. In addition, handling the
Conformational Markov Network, relevant kinetic magnitudes as dwell times or
rate constants, and the hierarchical relationship among basins, complete the
global picture of the landscape. We show the power of the analysis studying a
toy model of a funnel-like potential and computing efficiently the conformers
of a short peptide, the dialanine, paving the way to a systematic study of the
Free Energy Landscape in large peptides.Comment: PLoS Computational Biology (in press
A Geographically-Restricted but Prevalent Mycobacterium tuberculosis Strain Identified in the West Midlands Region of the UK between 1995 and 2008
Background: We describe the identification of, and risk factors for, the single most prevalent Mycobacterium tuberculosis strain in the West Midlands region of the UK.Methodology/Principal Findings: Prospective 15-locus MIRU-VNTR genotyping of all M. tuberculosis isolates in the West Midlands between 2004 and 2008 was undertaken. Two retrospective epidemiological investigations were also undertaken using univariable and multivariable logistic regression analysis. The first study of all TB patients in the West Midlands between 2004 and 2008 identified a single prevalent strain in each of the study years (total 155/3,056 (5%) isolates). This prevalent MIRU-VNTR profile (32333 2432515314 434443183) remained clustered after typing with an additional 9-loci MIRU-VNTR and spoligotyping. The majority of these patients (122/155, 79%) resided in three major cities located within a 40 km radius. From the apparent geographical restriction, we have named this the "Mercian" strain. A multivariate analysis of all TB patients in the West Midlands identified that infection with a Mercian strain was significantly associated with being UK-born (OR = 9.03, 95% CI = 4.56-17.87, p 65 years old (OR = 0.25, 95% CI = 0.09-0.67, p < 0.01). A second more detailed investigation analyzed a cohort of 82 patients resident in Wolverhampton between 2003 and 2006. A significant association with being born in the UK remained after a multivariate analysis (OR = 9.68, 95% CI = 2.00-46.78, p < 0.01) and excess alcohol intake and cannabis use (OR = 6.26, 95% CI = 1.45-27.02, p = .01) were observed as social risk factors for infection.Conclusions/Significance: The continued consistent presence of the Mercian strain suggests ongoing community transmission. Whilst significant associations have been found, there may be other common risk factors yet to be identified. Future investigations should focus on targeting the relevant risk groups and elucidating the biological factors that mediate continued transmission of this strain
Mitochondria are the main source and one of the targets of Pb (lead)-induced oxidative stress in the yeast Saccharomyces cerevisiae
The yeast Saccharomyces cerevisiae is a useful model organism for studying lead (Pb) toxicity. Yeast cells of a laboratory S. cerevisiae strain (WT strain) were incubated with Pb concentrations up to 1,000 μmol/l for 3 h. Cells exposed to Pb lost proliferation capacity without damage to the cell membrane, and they accumulated intracellular superoxide anion (O2 .−) and hydrogen peroxide (H2O2). The involvement of the mitochondrial electron transport chain (ETC) in the generation of reactive oxygen species (ROS) induced by Pb was evaluated. For this purpose, an isogenic derivative ρ0 strain, lacking mitochondrial DNA, was used. The ρ0 strain, without respiratory competence, displayed a lower intracellular ROS accumulation and a higher resistance to Pb compared to the WT strain. The kinetic study of ROS generation in yeast cells exposed to Pb showed that the production of O2 .− precedes the accumulation of H2O2, which is compatible with the leakage of electrons from the mitochondrial ETC. Yeast cells exposed to Pb displayed mutations at the mitochondrial DNA level. This is most likely a consequence of oxidative stress. In conclusion, mitochondria are an important source of Pb-induced ROS and, simultaneously, one of the targets of its toxicity.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013
Stable reference genes for the measurement of transcript abundance during larval caste development in the honeybee
Many genes are differentially regulated by caste development in the honeybee. Identifying and understanding these differences is key to discovering the mechanisms underlying this process. To identify these gene expression differences requires robust methods to measure transcript abundance. RT-qPCR is currently the gold standard to measure gene expression, but requires stable reference genes to compare gene expression changes. Such reference genes have not been established for honeybee caste development. Here, we identify and test potential reference genes that have stable expression throughout larval development between the two female castes. In this study, 15 candidate reference genes were examined to identify the most stable reference genes. Three algorithms (GeNorm, Bestkeeper and NormFinder) were used to rank the candidate reference genes based on their stability between the castes throughout larval development. Of these genes Ndufa8 (the orthologue of a component of complex one of the mitochondrial electron transport chain) and Pros54 (orthologous to a component of the 26S proteasome) were identified as being the most stable. When these two genes were used to normalise expression of two target genes (previously found to be differentially expressed between queen and worker larvae by microarray analysis) they were able to more accurately detect differential expression than two previously used reference genes (awd and RpL12). The identification of these novel reference genes will be of benefit to future studies of caste development in the honeybee
Proteomics: in pursuit of effective traumatic brain injury therapeutics
Effective traumatic brain injury (TBI) therapeutics remain stubbornly elusive. Efforts in the field have been challenged by the heterogeneity of clinical TBI, with greater complexity among underlying molecular phenotypes than initially conceived. Future research must confront the multitude of factors comprising this heterogeneity, representing a big data challenge befitting the coming informatics age. Proteomics is poised to serve a central role in prescriptive therapeutic development, as it offers an efficient endpoint within which to assess post-TBI biochemistry. We examine rationale for multifactor TBI proteomic studies and the particular importance of temporal profiling in defining biochemical sequences and guiding therapeutic development. Lastly, we offer perspective on repurposing biofluid proteomics to develop theragnostic assays with which to prescribe, monitor and assess pharmaceutics for improved translation and outcome for TBI patients
Clinical course, costs and predictive factors for response to treatment in carpal tunnel syndrome: The PALMS study protocol
Background Carpal tunnel syndrome (CTS) is the most common neuropathy of the upper limb and a significant contributor to hand functional impairment and disability. Effective treatment options include conservative and surgical interventions, however it is not possible at present to predict the outcome of treatment. The primary aim of this study is to identify which baseline clinical factors predict a good outcome from conservative treatment (by injection) or surgery in patients diagnosed with carpal tunnel syndrome. Secondary aims are to describe the clinical course and progression of CTS, and to describe and predict the UK cost of CTS to the individual, National Health Service (NHS) and society over a two year period. Methods/Design In this prospective observational cohort study patients presenting with clinical signs and symptoms typical of CTS and in whom the diagnosis is confirmed by nerve conduction studies are invited to participate. Data on putative predictive factors are collected at baseline and follow-up through patient questionnaires and include standardised measures of symptom severity, hand function, psychological and physical health, comorbidity and quality of life. Resource use and cost over the 2 year period such as prescribed medications, NHS and private healthcare contacts are also collected through patient self-report at 6, 12, 18 and 24 months. The primary outcome used to classify treatment success or failures will be a 5-point global assessment of change. Secondary outcomes include changes in clinical symptoms, functioning, psychological health, quality of life and resource use. A multivariable model of factors which predict outcome and cost will be developed. Discussion This prospective cohort study will provide important data on the clinical course and UK costs of CTS over a two-year period and begin to identify predictive factors for treatment success from conservative and surgical interventions
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