205 research outputs found

    Differences in callosal and subcortical volumes and associated neurobehavioural deficits in children with prenatal alcohol exposure

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    Certain high-risk communities in the Western Cape Province of South Africa where heavy maternal prenatal alcohol consumption is perpetuated by historical and societal challenges, have some of the highest prevalence rates of fetal alcohol syndrome (FAS) in the world. FAS has lifelong behavioural and cognitive consequences. Neuroimaging research aims to link deficits in brain structure and function to behavioural outcomes. Manual tracing is considered the gold standard of neuroanatomical volumetric analysis. Combined with neurobehavioural testing it can provide links between structure and function, but is time consuming and labour intensive. Automated segmentation programmes, such as FreeSurfer, are a faster alternative. The challenge is creating automated programmes that can provide results that are comparable to manual tracing, especially in a clinical sample. The aims of this thesis were to investigate (1) the effects of prenatal alcohol exposure (PAE) on the sizes of the caudate nucleus, nucleus accumbens, hippocampus and corpus callosum (CC) and potential relations of regional volumes with IQ and verbal learning, (2) to compare the performance of manual and automated segmentation methods in identifying alcohol-related changes in brain morphometry, and (3) to examine the effects of PAE on inter-hemispheric transfer during adolescence and potential relations of CC size with inter-hemispheric transfer deficits. Participants for this project were recruited from the Cape Town Longitudinal Cohort for whom alcohol exposure data were gathered prospectively from the mothers during pregnancy using the timeline follow-back approach. Participants had been diagnosed previously by two expert dysmorphologists as either control, non-syndromal heavily exposed (HE), partial FAS (PFAS) or FAS. High-resolution T1-weighted images were acquired using a sequence optimized for morphometric neuroanatomical analysis on a Siemens 3T Allegra MRI scanner for 71 right-handed children (9 FAS, 19 PFAS, 24 HE and 19 non-exposed controls) from this cohort at ages 9-11 years. Bilateral caudate nuclei, nucleus accumbens and hippocampi and the CC were manually traced using Multitracer. FreeSurfer was used for automated segmentation. All structures were segmented with both FreeSurfer versions 5.1 and 6.0 to compare progress within development of automated segmentation algorithms. Associations of volumes from manual tracing with IQ and performance on the California Verbal Learning Test-Children’s Version (CVLT-C) were also examined. Inter-hemispheric transfer was assessed using a finger localization task (FLT) administered to 74 participants (12 FAS, 16 PFAS, 14 HE, and 32 controls) from the same cohort at ages 16-17 years. Of these, 34 participants had completed MRI at 9-11 years. Higher levels of PAE were associated with reductions in CC area, as well as bilateral volume reductions in caudate nuclei and hippocampi, effects that remained significant after controlling for alcohol-related reductions in TIV (total intracranial volume). Amongst dysmorphic children (FAS/PFAS), poorer performance on the CVLT-C was related to larger hippocampi and smaller CC. Smaller CC was also associated with lower IQ and partially mediated the effect of PAE on IQ. Manual and automated comparisons showed good agreement in the caudate nuclei, which are simpler to segment, moderate to good agreement in the smaller, more complex nucleus accumbens and hippocampi, and poor agreement in the CC. The latter is not surprising, however, in view of the fact that manual tracing measured the average area of the CC on a mid-sagittal slice, while FreeSurfer measures CC volume over a number of contiguous slices. After controlling for confounders and adjustment for smaller TIV, the latest FreeSurfer version 6.0 provided evidence of alcohol-related volumetric brain reductions comparable to manual segmentation. Only the most severely affected children with FAS demonstrated inter-hemispheric transfer deficits, with the number of transfer-related errors tending to increase with decreasing CC volume among children with PAE. This study confirms and extends evidence of PAE-related decreases in subcortical and CC size and that callosal volume partially mediates alcohol-related impairment in IQ. Although FreeSurfer v 6.0 achieves automated segmentations that are comparable to manual tracing, even in a paediatric clinical sample, performance is more reliable in some structures than others. Improvement and standardization of CC segmentation is especially important given the vulnerability of the CC and its critical role in domains affected by PAE, including verbal learning, IQ and inter-hemispheric transfer of information

    The paternal transition entails neuroanatomic adaptations that are associated with the father's brain response to his infant cues

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    The transition into fatherhood is a life-changing event that requires substantial psychological adaptations. In families that include a father figure, sensitive paternal behavior has been shown to positively impact the infant's development. Yet, studies exploring the neuroanatomic adaptations of men in their transition into fatherhood are scarce. The present study used surface-based methods to reanalyze a previously published prospective magnetic resonance imaging dataset comprised of 20 first-time fathers (preconception-to-postpartum) and 17 childless men. We tested if the transition into fatherhood entailed changes in cortical volume, thickness, and area and whether these changes were related to 2 indicators of paternal experience. Specifically, we tested if such changes were associated with (1) the baby's age and/or (2) the fathers' brain activity in response to pictures of their babies compared with an unknown baby. Results indicated that first-time fathers exhibited a significant reduction in cortical volume and thickness of the precuneus. Moreover, higher volume reduction and cortical thinning were associated with stronger brain responses to pictures of their own baby in parental brain regions. This is the first study showing preconception-to-postpartum neuroanatomical adaptations in first-time fathers associated with the father's brain response to cues of his infant.Ministerio de Ciencia, Innovación y Universidades project (RTI2018-093952-B-100); Instituto de Salud Carlos III projects (CP16/00096 and PI17/00064); cofunded by European Regional Development Fund, "A way of making Europe" and by "La Caixa" Foundation under the project code LCF/PR/HR19/52160001, and by the European Research Council under the project code 883069. The project ASPIDE has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement number 801091. M.M.G. and S.S.C. were funded by Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III (PFIS contract FI18/00255 and Miguel Servet Type I research contract CP16/00096, respectively), and cofunded by European Social Fund "Investing in your future". The Centro Nacional de Investigaciones Cardiovasculares is supported by the Ministerio de Ciencia, Innovación y Universidades and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Genome-Wide Linkage and Association Mapping of Halo Blight Resistance in Common Bean to Race 6 of the Globally Important Bacterial Pathogen.

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    Pseudomonas syringae pv. phaseolicola (Psph) Race 6 is a globally prevalent and broadly virulent bacterial pathogen with devastating impact causing halo blight of common bean (Phaseolus vulgaris L.). Common bean lines PI 150414 and CAL 143 are known sources of resistance against this pathogen. We constructed high-resolution linkage maps for three recombinant inbred populations to map resistance to Psph Race 6 derived from the two common bean lines. This was complemented with a genome-wide association study (GWAS) of Race 6 resistance in an Andean Diversity Panel of common bean. Race 6 resistance from PI 150414 maps to a single major-effect quantitative trait locus (QTL; HB4.2) on chromosome Pv04 and confers broad-spectrum resistance to eight other races of the pathogen. Resistance segregating in a Rojo × CAL 143 population maps to five chromosome arms and includes HB4.2. GWAS detected one QTL (HB5.1) on chromosome Pv05 for resistance to Race 6 with significant influence on seed yield. The same HB5.1 QTL, found in both Canadian Wonder × PI 150414 and Rojo × CAL 143 populations, was effective against Race 6 but lacks broad resistance. This study provides evidence for marker-assisted breeding for more durable halo blight control in common bean by combining alleles of race-nonspecific resistance (HB4.2 from PI 150414) and race-specific resistance (HB5.1 from cv. Rojo)

    Chemotactic activity of extracellular nucleotideson human immune cells.

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    Purinergic P2 receptors are a class of plasma membrane receptors that are express in many tissues and are ligated by extracellular nucleotides [such as adenosine triphosphate (ATP), adenosine diphosphate (ADP), uridine 5–triphosphate (UTP) and uridine 5–diphosphate (UDP)], which are released as a consequence of cell damage, cell stress, bacterial infection or other noxious stimuli. According to the molecular structure, P2 receptors are divided into two subfamilies: P2X and P2Y receptors. The P2X receptors are ligand-gated channels, whereas P2Y receptors are G-protein-coupled seven-membrane-spanning receptors. Several studies indicate that nucleotides play an important role in immune response modulation through their action on multiple cell types, including monocytes, mast cells, dendritic cells, neutrophils, and eosinophils. Recent work by our group and others identified extracellular nucleotides as chemotaxins for various human immune cells, including eosinophils, neutrophils and dendritic cells. In this review, we summarise recent findings in this field and put forward a hypothesis on the role of P2 receptors in the early recruitment of human immune cells to the site of inflammation

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    On the Inheritance of Strength in Wheat

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    The Improvement of English Wheat

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