Nickel and osmium isotope and trace element geochemistry of organic-rich sedimentary rocks: The first investigation of Ni isotope systematics in marine sediments

Understanding the chemical composition of organic-rich marine sediments has the potential to: 1) allow evaluation of variations in ocean chemistry, enabling assessment of changes in global processes throughout geological time; and 2) provide an increased temporal and spatial understanding of petroleum systems. Herein two geologically distinct organic-rich sedimentary formations are explored utilising trace elements, and rhenium-osmium (Re-Os) and nickel (Ni) isotope systematics. Additionally, this thesis is the first study to investigate the behaviour of Ni isotope systematics in organic-rich marine sediments. Osmium isotope profiling across the Sinemurian-Pliensbachian boundary GSSP indicates that there was a significant contribution of unradiogenic Os to the oceans at this time. Seawater 187Os/188Os(i) values range from ~0.20 – 0.48, becoming increasingly unradiogenic up-section. This progressive change in ocean chemistry is coincident with flooding of the Hispanic Corridor, formed during rifting of the Pangean supercontinent and creation of the Central Atlantic Ocean, evident from sudden levels of faunal exchange between the eastern Pacific and western Tethyan oceans. The Os isotope signal here reflects the onset of hydrothermal activity associated with formation of the Hispanic Corridor. New Ni stable isotope data presented herein for the Sinemurian-Pliensbachian (S-P) GSSP and the Devonian-Mississippian Exshaw Formation, demonstrates that organic-rich marine sediments are characterised by δ60Ni values that are distinct to those of extraterrestrial and abiotic terrestrial samples. Further, the level of Ni isotope fractionation in organic-rich sediments (ranging from ~1.32 ‰ in the S-P sediments, and ~2.04 ‰ in the Exshaw Formation) is far greater than that seen in the other sample suites (ranges of ~0.17 – 0.37 ‰; Cameron et al., 2009). Although there are limited datasets available for comparison at present, the ranges of δ60Ni values for the S-P GSSP and Exshaw Formation are similar (0.28 ± 0.05 to 1.60 ±0.05 ‰ and 0.46 ± 0.04 to 2.50 ± 0.04 ‰, respectively), suggesting that such variation in Ni isotope fractionation may be characteristic of organic-rich sediments. This may be due to complexities that are ubiquitous to the sediment-seawater depositional environment. In addition, trace element ratios utilised to establish depositional paleoredox conditions demonstrate that redox did not exert control on the level of Ni isotope fractionation observed in these sediments. The study herein also demonstrates that thermal maturation of the Exshaw Formation has a negligible effect on Ni isotope systematics in mature source rocks, strongly suggesting that Ni isotopes may have the potential to be developed as an oil-source correlation tool

A qualitative study exploring the social and environmental context of recently acquired HIV infection among men who have sex with men in South-East England.

OBJECTIVES: A key UK public health priority is to reduce HIV incidence among gay and other men who have sex with men (MSM). This study aimed to explore the social and environmental context in which new HIV infections occurred among MSM in London and Brighton in 2015. DESIGN: A qualitative descriptive study, comprising in-depth interviews, was carried out as a substudy to the UK Register of HIV Seroconverters cohort: an observational cohort of individuals whose date of HIV seroconversion was well estimated. An inductive thematic analysis was conducted in NVivo, guided by a socio-ecological framework. SETTING: Participants were recruited from six HIV clinics in London and Brighton. Fieldwork was conducted between January and April 2015. PARTICIPANTS: All MSM eligible for the UK Register Seroconverter cohort (an HIV-positive antibody test result within 12 months of their last documented HIV-negative test or other laboratory evidence of HIV seroconversion) diagnosed within the past 12 months and aged ≥18 were eligible for the qualitative substudy. 21 MSM participated, aged 22-61 years and predominantly white. RESULTS: A complex interplay of factors, operating at different levels, influenced risk behaviours and HIV acquisition. Participants saw risk as multi-factorial, but the relative importance of factors varied for each person. Individual psycho-social factors, including personal history, recent life stressors and mental health, enhanced vulnerability towards higher risk situations, while features of the social environment, such as chemsex and social media, and prevalent community beliefs regarding treatment and HIV normalisation, encouraged risk taking. CONCLUSIONS: Recently acquired HIV infection among MSM reflects a complex web of factors operating at different levels. These findings point to the need for multi-level interventions to reduce the risk of HIV acquisition among high-risk MSM in the UK and similar settings

Support and Assessment for Fall Emergency Referrals (SAFER 1) trial protocol. Computerised on-scene decision support for emergency ambulance staff to assess and plan care for older people who have fallen: evaluation of costs and benefits using a pragmatic cluster randomised trial

Background: Many emergency ambulance calls are for older people who have fallen. As half of them are left at home, a community-based response may often be more appropriate than hospital attendance. The SAFER 1 trial will assess the costs and benefits of a new healthcare technology - hand-held computers with computerised clinical decision support (CCDS) software - to help paramedics decide who needs hospital attendance, and who can be safely left at home with referral to community falls services. Methods/Design: Pragmatic cluster randomised trial with a qualitative component. We shall allocate 72 paramedics ('clusters') at random between receiving the intervention and a control group delivering care as usual, of whom we expect 60 to complete the trial. Patients are eligible if they are aged 65 or older, live in the study area but not in residential care, and are attended by a study paramedic following an emergency call for a fall. Seven to 10 days after the index fall we shall offer patients the opportunity to opt out of further follow up. Continuing participants will receive questionnaires after one and 6 months, and we shall monitor their routine clinical data for 6 months. We shall interview 20 of these patients in depth. We shall conduct focus groups or semi-structured interviews with paramedics and other stakeholders. The primary outcome is the interval to the first subsequent reported fall (or death). We shall analyse this and other measures of outcome, process and cost by 'intention to treat'. We shall analyse qualitative data thematically. Discussion: Since the SAFER 1 trial received funding in August 2006, implementation has come to terms with ambulance service reorganisation and a new national electronic patient record in England. In response to these hurdles the research team has adapted the research design, including aspects of the intervention, to meet the needs of the ambulance services. In conclusion this complex emergency care trial will provide rigorous evidence on the clinical and cost effectiveness of CCDS for paramedics in the care of older people who have fallen

Enhanced normalisation of CD4/CD8 ratio with early antiretroviral therapy in primary HIV infection

INTRODUCTION: Despite normalization of total CD4 counts, ongoing immune dysfunction is noted amongst those on antiretroviral therapy (ART). Low CD4/CD8 ratio is associated with a high risk of AIDS and non-AIDS events and may act as a marker of immune senescence [1]. This ratio is improved by ART although normalization is uncommon (~7%) [2]. The probability of normalization of CD4 count is improved with immediate ART initiation in primary HIV infection (PHI) [3]. We examined whether CD4/CD8 ratio similarly normalized in immediate vs. deferred ART at PHI. MATERIAL AND METHODS: Using data from the SPARTAC trial and the UK Register of HIV Seroconverters, we examined the effect of ART with time (continuous) from HIV seroconversion (SC) on CD4/CD8 ratio (≥1) adjusted for sex, risk group, ethnicity, enrolment from an African site and both CD4 count and age at ART initiation. We also examined that effect by dichotomizing HIV duration at ART initiation (ART started within six months of SC: early ART; ART initiated>six months after SC: deferred). We also considered time to CD4 count normalization (≥900 cells/mm(3)). RESULTS: In total, 353 initiated ART with median (IQR) 97.9 (60.5, 384.5) days from estimated seroconversion; 253/353 early ART, 100 deferred ART. At one year after starting ART, 114/253 (45%) early ART had normalized CD4/8 ratio, compared with 11/99 (11%) in the deferred group, whilst 83/253 (33%) of early ART had normalized CD4 counts, compared with 3/99 (3%) in the deferred group. Individuals initiating within six months of PHI were significantly more likely to reach normal ratio than those initiating later (HR, 95% CI 2.96, 1.75 - 5.01, p<0.001). The longer after SC ART was initiated, the reduced likelihood of achieving normalization of CD4/CD8 ratio (HR 0.98, 95% CI 0.96 - 0.99 for each 30-day increase). CD4 count at ART initiation was also associated with normalization, as expected (HR 1.002, 95% CI 1.001 - 1.002, p<0.001). There was an association between normal CD4/CD8 ratio and being virally suppressed (<400 copies HIV RNA/ml) p<0.001. CD4 count normalization was also significantly more likely for those initiating early (HR 5.00, 95% CI 1.52 - 16.41, p=0.008). CONCLUSIONS: The likelihood of achieving normalization of CD4/CD8 ratios was increased if ART was initiated within six months of PHI. Higher CD4/CD8 ratio may reflect a more 'normal' immune phenotype conferring enhanced prognosis and predict post-treatment control

Enhanced normalisation of CD4/CD8 ratio with early antiretroviral therapy in primary HIV infection

Introduction: Despite normalization of total CD4 counts, ongoing immune dysfunction is noted amongst those on antiretroviral therapy (ART). Low CD4/CD8 ratio is associated with a high risk of AIDS and non-AIDS events and may act as a marker of immune senescence [1]. This ratio is improved by ART although normalization is uncommon (7%) [2]. The probability of normalization of CD4 count is improved with immediate ART initiation in primary HIV infection (PHI) [3]. We examined whether CD4/CD8 ratio similarly normalized in immediate vs. deferred ART at PHI. Methods: Using data from the SPARTAC trial and the UK Register of HIV Seroconverters, we examined the effect of ART with time (continuous) from HIV seroconversion (SC) on CD4/CD8 ratio (]1) adjusted for sex, risk group, ethnicity, enrolment from an African site and both CD4 count and age at ART initiation. We also examined that effect by dichotomizing HIV duration at ART initiation (ART started within six months of SC: early ART; ART initiatedsix months after SC: deferred). We also considered time to CD4 count normalization (]900 cells/mm3 ). Results: In total, 353 initiated ART with median (IQR) 97.9 (60.5, 384.5) days from estimated seroconversion; 253/353 early ART, 100 deferred ART. At one year after starting ART, 114/253 (45%) early ART had normalized CD4/8 ratio, compared with 11/99 (11%) in the deferred group, whilst 83/253 (33%) of early ART had normalized CD4 counts, compared with 3/99 (3%) in the deferred group. Individuals initiating within six months of PHI were significantly more likely to reach normal ratio than those initiating later (HR, 95% CI 2.96, 1.755.01, pB0.001). The longer after SC ART was initiated, the reduced likelihood of achieving normalization of CD4/CD8 ratio (HR 0.98, 95% CI 0.960.99 for each 30-day increase). CD4 count at ART initiation was also associated with normalization, as expected (HR 1.002, 95% CI 1.0011.002, pB0.001). There was an association between normal CD4/CD8 ratio and being virally suppressed (B400 copies HIV RNA/ml) pB0.001. CD4 count normalization was also significantly more likely for those initiating early (HR 5.00, 95% CI 1.5216.41, p0.008). Conclusions: The likelihood of achieving normalization of CD4/CD8 ratios was increased if ART was initiated within six months of PHI. Higher CD4/CD8 ratio may reflect a more ‘‘normal’’ immune phenotype conferring enhanced prognosis and predict posttreatment control. Refe

Paramedic assessment of older adults after falls, including community care referral pathway : cluster randomized trial

Study objective We aim to determine clinical and cost-effectiveness of a paramedic protocol for the care of older people who fall. Methods We undertook a cluster randomized trial in 3 UK ambulance services between March 2011 and June 2012. We included patients aged 65 years or older after an emergency call for a fall, attended by paramedics based at trial stations. Intervention paramedics could refer the patient to a community-based falls service instead of transporting the patient to the emergency department. Control paramedics provided care as usual. The primary outcome was subsequent emergency contacts or death. Results One hundred five paramedics based at 14 intervention stations attended 3,073 eligible patients; 110 paramedics based at 11 control stations attended 2,841 eligible patients. We analyzed primary outcomes for 2,391 intervention and 2,264 control patients. One third of patients made further emergency contacts or died within 1 month, and two thirds within 6 months, with no difference between groups. Subsequent 999 call rates within 6 months were lower in the intervention arm (0.0125 versus 0.0172; adjusted difference –0.0045; 95% confidence interval –0.0073 to –0.0017). Intervention paramedics referred 8% of patients (204/2,420) to falls services and left fewer patients at the scene without any ongoing care. Intervention patients reported higher satisfaction with interpersonal aspects of care. There were no other differences between groups. Mean intervention cost was $23 per patient, with no difference in overall resource use between groups at 1 or 6 months. Conclusion A clinical protocol for paramedics reduced emergency ambulance calls for patients attended for a fall safely and at modest cost

CD32-Expressing CD4 T Cells Are Phenotypically Diverse and Can Contain Proviral HIV DNA.

Efforts to both characterize and eradicate the HIV reservoir have been limited by the rarity of latently infected cells and the absence of a specific denoting biomarker. CD32a (FcγRIIa) has been proposed to be a marker for an enriched CD4 T cell HIV reservoir, but this finding remains controversial. Here, we explore the expression of CD32 on CD3+CD4+ cells in participants from two primary HIV infection studies and identify at least three distinct phenotypes (CD32low, CD32+CD14+, and CD32high). Of note, CD4 negative enrichment kits remove the majority of CD4+CD32+ T cells, potentially skewing subsequent analyses if used. CD32high CD4 T cells had higher levels of HLA-DR and HIV co-receptor expression than other subsets, compatible with their being more susceptible to infection. Surprisingly, they also expressed high levels of CD20, TCRαβ, IgD, and IgM (but not IgG), markers for both T cells and naïve B cells. Compared with other populations, CD32low cells had a more differentiated memory phenotype and high levels of immune checkpoint receptors, programmed death receptor-1 (PD-1), Tim-3, and TIGIT. Within all three CD3+CD4+CD32+ phenotypes, cells could be identified in infected participants, which contained HIV DNA. CD32 expression on CD4 T cells did not correlate with HIV DNA or cell-associated HIV RNA (both surrogate measures of overall reservoir size) or predict time to rebound viremia following treatment interruption, suggesting that it is not a dominant biomarker for HIV persistence. Our data suggest that while CD32+ T cells can be infected with HIV, CD32 is not a specific marker of the reservoir although it might identify a population of HIV enriched cells in certain situations

CD32-Expressing CD4 T Cells Are Phenotypically Diverse and Can Contain Proviral HIV DNA.

Efforts to both characterize and eradicate the HIV reservoir have been limited by the rarity of latently infected cells and the absence of a specific denoting biomarker. CD32a (FcγRIIa) has been proposed to be a marker for an enriched CD4 T cell HIV reservoir, but this finding remains controversial. Here, we explore the expression of CD32 on CD3+CD4+ cells in participants from two primary HIV infection studies and identify at least three distinct phenotypes (CD32low, CD32+CD14+, and CD32high). Of note, CD4 negative enrichment kits remove the majority of CD4+CD32+ T cells, potentially skewing subsequent analyses if used. CD32high CD4 T cells had higher levels of HLA-DR and HIV co-receptor expression than other subsets, compatible with their being more susceptible to infection. Surprisingly, they also expressed high levels of CD20, TCRαβ, IgD, and IgM (but not IgG), markers for both T cells and naïve B cells. Compared with other populations, CD32low cells had a more differentiated memory phenotype and high levels of immune checkpoint receptors, programmed death receptor-1 (PD-1), Tim-3, and TIGIT. Within all three CD3+CD4+CD32+ phenotypes, cells could be identified in infected participants, which contained HIV DNA. CD32 expression on CD4 T cells did not correlate with HIV DNA or cell-associated HIV RNA (both surrogate measures of overall reservoir size) or predict time to rebound viremia following treatment interruption, suggesting that it is not a dominant biomarker for HIV persistence. Our data suggest that while CD32+ T cells can be infected with HIV, CD32 is not a specific marker of the reservoir although it might identify a population of HIV enriched cells in certain situations

Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.

BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment

RA-MAP, molecular immunological landscapes in early rheumatoid arthritis and healthy vaccine recipients

Rheumatoid arthritis (RA) is a chronic inflammatory disorder with poorly defined aetiology characterised by synovial inflammation with variable disease severity and drug responsiveness. To investigate the peripheral blood immune cell landscape of early, drug naive RA, we performed comprehensive clinical and molecular profiling of 267 RA patients and 52 healthy vaccine recipients for up to 18 months to establish a high quality sample biobank including plasma, serum, peripheral blood cells, urine, genomic DNA, RNA from whole blood, lymphocyte and monocyte subsets. We have performed extensive multi-omic immune phenotyping, including genomic, metabolomic, proteomic, transcriptomic and autoantibody profiling. We anticipate that these detailed clinical and molecular data will serve as a fundamental resource offering insights into immune-mediated disease pathogenesis, progression and therapeutic response, ultimately contributing to the development and application of targeted therapies for RA.</p