Fetal liver blood flow distribution: role in human developmental strategy to prioritize fat deposition versus brain development

Among primates, human neonates have the largest brains but also the highest proportion of body fat. If placental nutrient supply is limited, the fetus faces a dilemma: should resources be allocated to brain growth, or to fat deposition for use as a potential postnatal energy reserve? We hypothesised that resolving this dilemma operates at the level of umbilical blood distribution entering the fetal liver. In 381 uncomplicated pregnancies in third trimester, we measured blood flow perfusing the fetal liver, or bypassing it via the ductus venosus to supply the brain and heart using ultrasound techniques. Across the range of fetal growth and independent of the mother's adiposity and parity, greater liver blood flow was associated with greater offspring fat mass measured by dual-energy X-ray absorptiometry, both in the infant at birth (r = 0.43, P<0.001) and at age 4 years (r = 0.16, P = 0.02). In contrast, smaller placentas less able to meet fetal demand for essential nutrients were associated with a brain-sparing flow pattern (r = 0.17, p = 0.02). This flow pattern was also associated with a higher degree of shunting through ductus venosus (P = 0.04). We propose that humans evolved a developmental strategy to prioritize nutrient allocation for prenatal fat deposition when the supply of conditionally essential nutrients requiring hepatic inter-conversion is limited, switching resource allocation to favour the brain if the supply of essential nutrients is limited. Facilitated placental transfer mechanisms for glucose and other nutrients evolved in environments less affluent than those now prevalent in developed populations, and we propose that in circumstances of maternal adiposity and nutrient excess these mechanisms now also lead to prenatal fat deposition. Prenatal developmental influences play important roles in the human propensity to deposit fa

An inter-subunit protein-peptide interface that stabilizes the specific activity and oligomerization of the AAA+ chaperone Reptin

The work was supported by: the Czech Science Foundation 16-20860S (PM, LH) and 16-07321S (BV, TH), the project MEYS – NPS I – LO1413, and MH CZ - DRO (MMCI, 00209805); the BBSRC RASOR consortium (BB/C511599/1; United Kingdom); Cancer Research UK (C21383/A6950); The International Centre for Cancer Vaccine Science project carried out within the International Research Agendas programme of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund; A*STAR, Singapore and NSCC, Singapore.Reptin is a member of the AAA+ superfamily whose members can exist in equilibrium between monomeric apo forms and ligand bound hexamers. Inter-subunit protein-protein interfaces that stabilize Reptin in its oligomeric state are not well-defined. A self-peptide binding assay identified a protein-peptide interface mapping to an inter-subunit “rim” of the hexamer bridged by Tyrosine-340. A Y340A mutation reduced ADP-dependent oligomer formation using a gel filtration assay, suggesting that Y340 forms a dominant oligomer stabilizing side chain. The monomeric ReptinY340A mutant protein exhibited increased activity to its partner protein AGR2 in an ELISA assay, further suggesting that hexamer formation can preclude certain protein interactions. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) demonstrated that the Y340A mutation attenuated deuterium suppression of Reptin in this motif in the presence of ligand. By contrast, the tyrosine motif of Reptin interacts with a shallower pocket in the hetero-oligomeric structure containing Pontin and HDX-MS revealed no obvious role of the Y340 side chain in stabilizing the Reptin-Pontin oligomer. Molecular dynamic simulations (MDS) rationalized how the Y340A mutation impacts upon a normally stabilizing inter-subunit amino acid contact. MDS also revealed how the D299N mutation can, by contrast, remove oligomer de-stabilizing contacts. These data suggest that the Reptin interactome can be regulated by a ligand dependent equilibrium between monomeric and hexameric forms through a hydrophobic inter-subunit protein-protein interaction motif bridged by Tyrosine-340. Significance Discovering dynamic protein-protein interactions is a fundamental aim of research in the life sciences. An emerging view of protein-protein interactions in higher eukaryotes is that they are driven by small linear polypeptide sequences; the linear motif. We report on the use of linear-peptide motif screens to discover a relatively high affinity peptide-protein interaction for the AAA+ and pro-oncogenic protein Reptin. This peptide interaction site was shown to form a ‘hot-spot’ protein-protein interaction site, and validated to be important for ligand-induced oligomerization of the Reptin protein. These biochemical data provide a foundation to understand how single point mutations in Reptin can impact on its oligomerization and protein-protein interaction landscape.PostprintPeer reviewe

High-sensitivity troponin and the application of risk stratification thresholds in patients with suspected acute coronary syndrome

Background: Guidelines acknowledge the emerging role of high-sensitivity cardiac troponin (hs-cTnl) for risk stratification and the early rule-out of myocardial infarction, but multiple thresholds have been described. We evaluate the safety and effectiveness of risk stratification thresholds in patients with suspected acute coronary syndrome. Methods: Consecutive patients with suspected acute coronary syndrome (n=48 282) were enrolled in a multicenter trial across 10 hospitals in Scotland. In a prespecified secondary and observational analysis, we compared the performance of the limit of detection (<2 ng/L) and an optimized risk stratification threshold (<5 ng/L) using the Abbott high-sensitivity troponin I assay. Patients with myocardial injury at presentation, with ≤2 hours of symptoms or with ST-segment elevation myocardial infarction were excluded. The negative predictive value was determined in all patients and in subgroups for a primary outcome of myocardial infarction or cardiac death within 30 days. The secondary outcome was myocardial infarction or cardiac death at 12 months, with risk modeled using logistic regression adjusted for age and sex. Results: In total, 32 837 consecutive patients (61±17 years, 47% female) were included, of whom 23 260 (71%) and 12,716 (39%) had hs-cTnl concentrations of <5 ng/L and <2 ng/L at presentation. The negative predictive value for the primary outcome was 99.8% (95% CI, 99.7%–99.8%) and 99.9% (95% CI, 99.8%–99.9%) in those with hs-cTnl concentrations of <5 ng/L and <2 ng/L, respectively. At both thresholds, the negative predictive value was consistent in men and women and across all age groups, although the proportion of patients identified as low risk fell with increasing age. Compared with patients with hs-cTnl concentrations of ≥5 ng/L but <99th centile, the risk of myocardial infarction or cardiac death at 12 months was 77% lower in those <5 ng/L (5.3% vs 0.7%; adjusted odds ratio, 0.23 [95% CI, 0.19–0.28]) and 80% lower in those <2 ng/L (5.3% vs 0.3%; adjusted odds ratio, 0.20 [95% CI, 0.14–0.29]). Conclusions: Use of risk stratification thresholds for hs-cTnl identify patients with suspected acute coronary syndrome and at least 2 hours of symptoms as low risk at presentation irrespective of age and sex

The challenge of equipoise: qualitative interviews exploring the views of health professionals and women with multiple ipsilateral breast cancer on recruitment to a surgical randomised controlled feasibility trial

Background- A multicentre feasibility trial (MIAMI), comparing outcomes and quality of life of women with multiple ipsilateral breast cancer randomised to therapeutic mammoplasty or mastectomy, was conducted from September 2018 to March 2020. The MIAMI surgical trial aimed to investigate recruitment of sufficient numbers of women. Multidisciplinary teams at 10 breast care centres in the UK identified 190 with MIBC diagnosis; 20 were eligible for trial participation but after being approached only four patients were recruited. A nested qualitative study sought to understand the reasons for this lack of recruitment. Methods- Interviews were conducted from November 2019 to September 2020 with 17 staff from eight hospital-based breast care centres that recruited and attempted to recruit to MIAMI; and seven patients from four centres, comprising all patients who were recruited to the trial and some who declined to take part. Interviews were audio-recorded, anonymised and analysed using thematic methods of building codes into themes and sub-themes using the process of constant comparison. Results- Overarching themes of (1) influences on equipoise and recruitment and (2) effects of a lack of equipoise were generated. Within these themes, health professional themes described the barriers to recruitment as ‘the treatment landscape has changed’, ‘staff preferences and beliefs’ which influenced equipoise and patient advice; and how different the treatments were for patients. Patient themes of ‘altruism and timing of trial approach’, ‘influences from consultants and others’ and ‘diagnostic journey doubts’ all played a part in whether patients agreed to take part in the trial. Conclusions- Barriers to recruiting to breast cancer surgical trials can be significant, especially where there are substantial differences between the treatments being offered and a lack of equipoise communicated by healthcare professionals to patients. Patients can become overwhelmed by numerous requests for participation in research trials and inappropriate timing of trial discussions. Alternative study designs to the gold standard randomised control trial for surgical interventions may be required to provide the high-quality evidence on which to base practice

PHC Progression Model: A novel mixed-methods tool for measuring primary health care system capacity

High-performing primary health care (PHC) is essential for achieving universal health coverage. However, in many countries, PHC is weak and unable to deliver on its potential. Improvement is often limited by a lack of actionable data to inform policies and set priorities. To address this gap, the Primary Health Care Performance Initiative (PHCPI) was formed to strengthen measurement of PHC in low-income and middle-income countries in order to accelerate improvement. PHCPI´s Vital Signs Profile was designed to provide a comprehensive snapshot of the performance of a country´s PHC system, yet quantitative information about PHC systems´ capacity to deliver high-quality, effective care was limited by the scarcity of existing data sources and metrics. To systematically measure the capacity of PHC systems, PHCPI developed the PHC Progression Model, a rubric-based mixed-methods assessment tool. The PHC Progression Model is completed through a participatory process by in-country teams and subsequently reviewed by PHCPI to validate results and ensure consistency across countries. In 2018, PHCPI partnered with five countries to pilot the tool and found that it was feasible to implement with fidelity, produced valid results, and was highly acceptable and useful to stakeholders. Pilot results showed that both the participatory assessment process and resulting findings yielded novel and actionable insights into PHC strengths and weaknesses. Based on these positive early results, PHCPI will support expansion of the PHC Progression Model to additional countries to systematically and comprehensively measure PHC system capacity in order to identify and prioritise targeted improvement efforts.Fil: Ratcliffe, Hannah L.. Brigham And Women's Hospital; Estados Unidos. Harvard T.H. Chan School of Public Health; Estados UnidosFil: Schwarz, Dan. Harvard T.H. Chan School of Public Health; Estados Unidos. Brigham And Women's Hospital; Estados UnidosFil: Hirschhorn, Lisa R.. Northwestern University; Estados UnidosFil: Cejas, Cintia. Ministerio de Desarrollo Social; Argentina. Ministerio de Salud de la Nación; ArgentinaFil: DIallo, Abdoulaye. Ministry Of Health And Social Action; SenegalFil: Garcia Elorrio, Ezequiel. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fifield, Jocelyn. Brigham And Women's Hospital; Estados Unidos. Harvard T.H. Chan School of Public Health; Estados UnidosFil: Gashumba, DIane. Ministry of Health; RuandaFil: Hartshorn, Lucy. Harvard T.H. Chan School of Public Health; Estados Unidos. Brigham And Women's Hospital; Estados UnidosFil: Leydon, Nicholas. Bill And Melinda Gates Foundation; Estados UnidosFil: Mohamed, Mohamed. Ministry Of Health And Social Welfare Dar Es Salaam; TanzaniaFil: Nakamura, Yoriko. Results For Development; Estados UnidosFil: Ndiaye, Youssoupha. Ministry Of Health And Social Action; SenegalFil: Novignon, Jacob. Kwame Nkrumah University Of Science And Technology; GhanaFil: Ofosu, Anthony. Ghana Health Service; GhanaFil: Roder Dewan, Sanam. Organización de las Naciones Unidas. Unicef. Fondo de las Naciones Unidas para la Infancia; ArgentinaFil: Rwiyereka, Angelique. Global Health Issues and Solutions; Estados UnidosFil: Secci, Federica. The World Bank Group; Estados UnidosFil: Veillard, Jeremy H.. The World Bank Group; Estados UnidosFil: Bitton, Asaf. Harvard T.H. Chan School of Public Health; Estados Unidos. Brigham And Women's Hospital; Estados Unido

Multidisciplinary teams, and parents, negotiating common ground in shared-care of children with long-term conditions: A mixed methods study

Background: Limited negotiation around care decisions is believed to undermine collaborative working between parents of children with long-term conditions and professionals, but there is little evidence of how they actually negotiate their respective roles. Using chronic kidney disease as an exemplar this paper reports on a multi-method study of social interaction between multidisciplinary teams and parents as they shared clinical care. Methods. Phases 1 and 2: a telephone survey mapping multidisciplinary teams' parent-educative activities, and qualitative interviews with 112 professionals (Clinical-psychologists, Dietitians, Doctors, Nurses, Play-specialists, Pharmacists, Therapists and Social-workers) exploring their accounts of parent-teaching in the 12 British children's kidney units. Phase 3: six ethnographic case studies in two units involving observations of professional/parent interactions during shared-care, and individual interviews. We used an analytical framework based on concepts drawn from Communities of Practice and Activity Theory. Results: Professionals spoke of the challenge of explaining to each other how they are aware of parents' understanding of clinical knowledge, and described three patterns of parent-educative activity that were common across MDTs: Engaging parents in shared practice; Knowledge exchange and role negotiation, and Promoting common ground. Over time, professionals had developed a shared repertoire of tools to support their negotiations with parents that helped them accomplish common ground during the practice of shared-care. We observed mutual engagement between professionals and parents where a common understanding of the joint enterprise of clinical caring was negotiated. Conclusions: For professionals, making implicit knowledge explicit is important as it can provide them with a language through which to articulate more clearly to each other what is the basis of their intuition-based hunches about parents' support needs, and may help them to negotiate with parents and accelerate parents' learning about shared caring. Our methodology and results are potentially transferrable to shared management of other conditions. © 2013 Swallow et al.; licensee BioMed Central Ltd

Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages

A small scale sample nuclear waste package, consisting of a 28 mm diameter uranium penny encased in grout, was imaged by absorption contrast radiography using a single pulse exposure from an X-ray source driven by a high-power laser. The Vulcan laser was used to deliver a focused pulse of photons to a tantalum foil, in order to generate a bright burst of highly penetrating X-rays (with energy >500 keV), with a source size of <0.5 mm. BAS-TR and BAS-SR image plates were used for image capture, alongside a newly developed Thalium doped Caesium Iodide scintillator-based detector coupled to CCD chips. The uranium penny was clearly resolved to sub-mm accuracy over a 30 cm2 scan area from a single shot acquisition. In addition, neutron generation was demonstrated in situ with the X-ray beam, with a single shot, thus demonstrating the potential for multi-modal criticality testing of waste materials. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material. With recent developments of high-power laser systems, to 10 Hz operation, a laser-driven multi-modal beamline for waste monitoring applications is envisioned

Extinction risk and conservation of the world\u27s sharks and rays

The rapid expansion of human activities threatens ocean-wide biodiversity. Numerous marine animal populations have declined, yet it remains unclear whether these trends are symptomatic of a chronic accumulation of global marine extinction risk. We present the first systematic analysis of threat for a globally distributed lineage of 1,041 chondrichthyan fishes&mdash;sharks, rays, and chimaeras. We estimate that one-quarter are threatened according to IUCN Red List criteria due to overfishing (targeted and incidental). Large-bodied, shallow-water species are at greatest risk and five out of the seven most threatened families are rays. Overall chondrichthyan extinction risk is substantially higher than for most other vertebrates, and only one-third of species are considered safe. Population depletion has occurred throughout the world&rsquo;s ice-free waters, but is particularly prevalent in the Indo-Pacific Biodiversity Triangle and Mediterranean Sea. Improved management of fisheries and trade is urgently needed to avoid extinctions and promote population recovery

Genomic profile of advanced breast cancer in circulating tumour DNA.

The genomics of advanced breast cancer (ABC) has been described through tumour tissue biopsy sequencing, although these approaches are limited by geographical and temporal heterogeneity. Here we use plasma circulating tumour DNA sequencing to interrogate the genomic profile of ABC in 800 patients in the plasmaMATCH trial. We demonstrate diverse subclonal resistance mutations, including enrichment of HER2 mutations in HER2 positive disease, co-occurring ESR1 and MAP kinase pathway mutations in HR + HER2- disease that associate with poor overall survival (p = 0.0092), and multiple PIK3CA mutations in HR + disease that associate with short progression free survival on fulvestrant (p = 0.0036). The fraction of cancer with a mutation, the clonal dominance of a mutation, varied between genes, and within hotspot mutations of ESR1 and PIK3CA. In ER-positive breast cancer subclonal mutations were enriched in an APOBEC mutational signature, with second hit PIK3CA mutations acquired subclonally and at sites characteristic of APOBEC mutagenesis. This study utilises circulating tumour DNA analysis in a large clinical trial to demonstrate the subclonal diversification of pre-treated advanced breast cancer, identifying distinct mutational processes in advanced ER-positive breast cancer, and novel therapeutic opportunities