146 research outputs found
A 3D U-net for Segmentation of Subcortical Structures in MR Images of 12 and 24 month-old infants
Recent research has determined links between the development of some neurodevelopmental disorders, including Autism Spectrum Disorder (ASD), and the morphometry of subcortical brain structures in children aged 12 and 24 months old, which is usually obtained via segmentation of a Magnetic Resonance (MR) image. Deep-learning based methods, such as the u-net, have emerged as the fastest way to compute segmentations with admissible accuracy. I have constructed a segmentation pipeline with a processing step and neural network step using a 3D u-net model trained on processed data from 830 automatically segmented images and 27 manually segmented images. The model is trained with a loss function that has structure volume and surface accuracy considerations. The segmentation pipeline is available as an open source software on GitHub. The model is validated on a set of 5 manually segmented images and obtains moderately good results compared to the state-of-the-art.Bachelor of Scienc
Effects of nicotine on alcohol drinking in female mice selectively-bred for high or low alcohol preference
Background
Studies show that repeated nicotine use associates with high alcohol consumption in humans, and that nicotine exposure sometimes increases alcohol consumption in animal models. However, the relative roles of genetic predisposition to high alcohol consumption, the alcohol drinking patterns, and the timing of nicotine exposure both with respect to alcohol drinking and developmental stage remain unclear. The studies here manipulated all these variables, using mice selectively bred for differences in free-choice alcohol consumption to elucidate the role of genetics and nicotine exposure in alcohol consumption behaviors.
Methods
In Experiments 1 and 2, we assessed the effects of repeated nicotine (0, 0.5 or 1.5 mg/kg) injections immediately before binge-like (drinking-in-the-dark; Experiment 1) or during free-choice alcohol access (Experiment 2) on these alcohol drinking behaviors (immediately after injections and during re-exposure to alcohol access 14 days later) in adult high- (HAP2) and low-alcohol preferring (LAP2) female mice (co-exposure model). In Experiments 3 and 4, we assessed the effects of repeated nicotine (0, 0.5 or 1.5 mg/kg) injections 14 days prior to binge-like and free-choice alcohol access on these alcohol drinking behaviors in adolescent HAP2 and LAP2 female mice (Experiment 3) or adult HAP2 female mice (Experiment 4).
Results
In Experiment 1, we found that repeated nicotine (0.5 and 1.5 mg/kg) and alcohol co-exposure significantly increased binge-like drinking behavior in HAP2 but not LAP2 mice during the re-exposure phase after a 14-day abstinence period. In Experiment 2, 1.5 mg/kg nicotine injections significantly reduced free-choice alcohol intake and preference in the 3rd hour post-injection in HAP2 but not LAP2 mice. No significant effects of nicotine treatment on binge-like or free-choice alcohol drinking were observed in Experiments 3 and 4.
Conclusions
These results show that the temporal parameters of nicotine and alcohol exposure, pattern of alcohol access, and genetic predisposition for alcohol preference influence nicotine's effects on alcohol consumption. These findings in selectively bred mice suggest that humans with a genetic history of alcohol-use disorders may be more vulnerable to develop nicotine and alcohol co-use disorders
Rumours, sects and rallies : the ethnic politics of recent Hmong Millenarian movements in Vietnam’s highlands
Contrary to modernist assumptions, millenarianism has not died out but continues to influence the politics of many marginalised groups in upland Southeast Asia, including the Hmong. This article summarises and analyses post-World War II Hmong millenarian activity in Vietnam, focusing on three case studies from the 1980s onwards, within the political backdrop of ongoing government suspicions of ethnic separatism and foreign interference. Far from being isolated or peripheral, Hmong millenarian rumours and movements interact with overseas diasporas, human rights agencies and international religious networks to influence state responses, sometimes in unexpected ways
Transcriptome sequencing and development of an expression microarray platform for the domestic ferret
<p>Abstract</p> <p>Background</p> <p>The ferret (<it>Mustela putorius furo</it>) represents an attractive animal model for the study of respiratory diseases, including influenza. Despite its importance for biomedical research, the number of reagents for molecular and immunological analysis is restricted. We present here a parallel sequencing effort to produce an extensive EST (expressed sequence tags) dataset derived from a normalized ferret cDNA library made from mRNA from ferret blood, liver, lung, spleen and brain.</p> <p>Results</p> <p>We produced more than 500000 sequence reads that were assembled into 16000 partial ferret genes. These genes were combined with the available ferret sequences in the GenBank to develop a ferret specific microarray platform. Using this array, we detected tissue specific expression patterns which were confirmed by quantitative real time PCR assays. We also present a set of 41 ferret genes with even transcription profiles across the tested tissues, indicating their usefulness as housekeeping genes.</p> <p>Conclusion</p> <p>The tools developed in this study allow for functional genomic analysis and make further development of reagents for the ferret model possible.</p
Concert recording 2018-02-09
[Track 1]. Marche á huit instrumens á vent / Nannette Streicher -- [Track 2]. Dixtuor pour instruments á vent. I. Allegro moderato II. Moderato [Track 3]. III. Andante - Allegro scherzando [Track 4]. IV. Cantabile [Track 5]. V. Allegro risoluto / Claude Arrieu, née Louise Marie Simon -- [Track 6]. Octet for windinstruments / Tera de Marez Oyens -- [Track 7]. The unfortunate traveller, suite for brass band. I. Introduction II. Scherzo [Track 8]. III. Interlude [Track 9]. IV. March / Imogen Holst
Cardiometabolic Health Among Adult Offspring of Hypertensive Pregnancies: The Cardiovascular Risk in Young Finns Study
Background: Cardiometabolic health among adult offspring of hypertensive disorders of pregnancy (HDP) is relatively unknown. We hypothesized that offspring of HDP would have abnormalities in the retinal microvasculature and cardiac structure by midadulthood.Methods and Results: The Cardiovascular Risk in Young Finns Study included randomly selected children from 5 Finnish university cities. The mean age of participants was 40 years (range 34–49 years) at the time of retinal photography and cardiac assessment. Offspring born ≥37 weeks of gestation and appropriate for gestational age (n=1006) were included. Offspring of HDP had higher systolic blood pressure (β=4.68, PConclusions: Abnormalities of the retinal microvasculature and cardiac structure are seen in offspring of HDP in midadulthood. These findings may need to be considered in future primary prevention strategies of cardiovascular disease among offspring of HDP.</p
Associations between unilateral amblyopia in childhood and cardiometabolic disorders in adult life: a cross-sectional and longitudinal analysis of the UK Biobank
Background Amblyopia is a common neurodevelopmental condition and leading cause of childhood visual impairment. Given the known association between neurodevelopmental impairment and cardiometabolic dysfunction in
later life, we investigated whether children with amblyopia have increased risk of cardiometabolic disorders in adult
life.
Methods This was a cross-sectional and longitudinal analysis of 126,399 United Kingdom Biobank cohort participants
who underwent ocular examination. A subset of 67,321 of these received retinal imaging. Data analysis was
conducted between November 1st 2021 and October 15th 2022. Our primary objective was to investigate the
association between amblyopia and a number of components of metabolic syndrome and individual
cardiometabolic diseases. Childhood amblyopia, dichotomised as resolved or persisting by adulthood,
cardiometabolic disease and mortality were defined using ophthalmic assessment, self-reported, hospital
admissions and death records. Morphological features of the optic nerve and retinal vasculature and sublayers
were extracted from retinal photography and optical coherence tomography. Associations between amblyopia and
cardiometabolic disorders as well as retinal markers were investigated in multivariable-adjusted regression models.
Findings Individuals with persisting amblyopia (n = 2647) were more likely to be obese (adjusted odds ratio (95%
confidence interval): 1.16 (1.05; 1.28)), hypertensive (1.25 (1.13; 1.38)) and diabetic (1.29 (1.04; 1.59)) than individuals
without amblyopia (controls, (n = 18,481)). Amblyopia was also associated with an increased risk of myocardial
infarction (adjusted hazard ratio: 1.38 (1.11; 1.72)) and death (1.36 (1.15; 1.60)). On retinal imaging, amblyopic eyes
had significantly increased venular caliber (0.29 units (0.21; 0.36)), increased tortuosity (0.11 units (0.03; 0.19)), but
lower fractal dimension (−0.23 units (−0.30; −0.16)) and thinner ganglion cell-inner plexiform layer (mGC-IPL, −2.85
microns (−3.47; −2.22)). Unaffected fellow eyes of individuals with amblyopia also had significantly lower retinal
fractal dimension (−0.08 units (−0.15; −0.01)) and thinner mGC-IPL (−1.14 microns (−1.74; −0.54)). Amblyopic
eyes with a persisting visual deficit had smaller optic nerve disc height (−0.17 units (−0.25; −0.08)) and width
(−0.13 units (−0.21; −0.04)) compared to control eyes.
Interpretation Although further research is needed to understand the basis of the observed associations, healthcare
professionals should be cognisant of greater cardiometabolic dysfunction in adults who had childhood amblyopia.
Differences in retinal features in both the amblyopic eye and the unaffected non-amblyopic suggest generalised
versus local processes
Alcohol use and burden for 195 countries and territories, 1990-2016 : a systematic analysis for the Global Burden of Disease Study 2016
Background Alcohol use is a leading risk factor for death and disability, but its overall association with health remains complex given the possible protective effects of moderate alcohol consumption on some conditions. With our comprehensive approach to health accounting within the Global Burden of Diseases, Injuries, and Risk Factors Study 2016, we generated improved estimates of alcohol use and alcohol-attributable deaths and disability-adjusted life-years (DALYs) for 195 locations from 1990 to 2016, for both sexes and for 5-year age groups between the ages of 15 years and 95 years and older. Methods Using 694 data sources of individual and population-level alcohol consumption, along with 592 prospective and retrospective studies on the risk of alcohol use, we produced estimates of the prevalence of current drinking, abstention, the distribution of alcohol consumption among current drinkers in standard drinks daily (defined as 10 g of pure ethyl alcohol), and alcohol-attributable deaths and DALYs. We made several methodological improvements compared with previous estimates: first, we adjusted alcohol sales estimates to take into account tourist and unrecorded consumption; second, we did a new meta-analysis of relative risks for 23 health outcomes associated with alcohol use; and third, we developed a new method to quantify the level of alcohol consumption that minimises the overall risk to individual health. Findings Globally, alcohol use was the seventh leading risk factor for both deaths and DALYs in 2016, accounting for 2.2% (95% uncertainty interval [UI] 1.5-3.0) of age-standardised female deaths and 6.8% (5.8-8.0) of age-standardised male deaths. Among the population aged 15-49 years, alcohol use was the leading risk factor globally in 2016, with 3.8% (95% UI 3.2-4-3) of female deaths and 12.2% (10.8-13-6) of male deaths attributable to alcohol use. For the population aged 15-49 years, female attributable DALYs were 2.3% (95% UI 2.0-2.6) and male attributable DALYs were 8.9% (7.8-9.9). The three leading causes of attributable deaths in this age group were tuberculosis (1.4% [95% UI 1. 0-1. 7] of total deaths), road injuries (1.2% [0.7-1.9]), and self-harm (1.1% [0.6-1.5]). For populations aged 50 years and older, cancers accounted for a large proportion of total alcohol-attributable deaths in 2016, constituting 27.1% (95% UI 21.2-33.3) of total alcohol-attributable female deaths and 18.9% (15.3-22.6) of male deaths. The level of alcohol consumption that minimised harm across health outcomes was zero (95% UI 0.0-0.8) standard drinks per week. Interpretation Alcohol use is a leading risk factor for global disease burden and causes substantial health loss. We found that the risk of all-cause mortality, and of cancers specifically, rises with increasing levels of consumption, and the level of consumption that minimises health loss is zero. These results suggest that alcohol control policies might need to be revised worldwide, refocusing on efforts to lower overall population-level consumption.Peer reviewe
Machine learning derived retinal pigment score from ophthalmic imaging shows ethnicity is not biology
Few metrics exist to describe phenotypic diversity within ophthalmic imaging datasets, with researchers often using ethnicity as a surrogate marker for biological variability. We derived a continuous, measured metric, the retinal pigment score (RPS), that quantifies the degree of pigmentation from a colour fundus photograph of the eye. RPS was validated using two large epidemiological studies with demographic and genetic data (UK Biobank and EPIC-Norfolk Study) and reproduced in a Tanzanian, an Australian, and a Chinese dataset. A genome-wide association study (GWAS) of RPS from UK Biobank identified 20 loci with known associations with skin, iris and hair pigmentation, of which eight were replicated in the EPIC-Norfolk cohort. There was a strong association between RPS and ethnicity, however, there was substantial overlap between each ethnicity and the respective distributions of RPS scores. RPS decouples traditional demographic variables from clinical imaging characteristics. RPS may serve as a useful metric to quantify the diversity of the training, validation, and testing datasets used in the development of AI algorithms to ensure adequate inclusion and explainability of the model performance, critical in evaluating all currently deployed AI models. The code to derive RPS is publicly available at: https://github.com/uw-biomedical-ml/retinal-pigmentation-score
Cerebral malaria in children: using the retina to study the brain
Cerebral malaria is a dangerous complication of Plasmodium falciparum infection, which takes a devastating toll on children in sub-Saharan Africa. Although autopsy studies have improved understanding of cerebral malaria pathology in fatal cases, information about in vivo neurovascular pathogenesis is scarce because brain tissue is inaccessible in life. Surrogate markers may provide insight into pathogenesis and thereby facilitate clinical studies with the ultimate aim of improving the treatment and prognosis of cerebral malaria. The retina is an attractive source of potential surrogate markers for paediatric cerebral malaria because, in this condition, the retina seems to sustain microvascular damage similar to that of the brain. In paediatric cerebral malaria a combination of retinal signs correlates, in fatal cases, with the severity of brain pathology, and has diagnostic and prognostic significance. Unlike the brain, the retina is accessible to high-resolution, non-invasive imaging. We aimed to determine the extent to which paediatric malarial retinopathy reflects cerebrovascular damage by reviewing the literature to compare retinal and cerebral manifestations of retinopathy-positive paediatric cerebral malaria. We then compared retina and brain in terms of anatomical and physiological features that could help to account for similarities and differences in vascular pathology. These comparisons address the question of whether it is biologically plausible to draw conclusions about unseen cerebral vascular pathogenesis from the visible retinal vasculature in retinopathy-positive paediatric cerebral malaria. Our work addresses an important cause of death and neurodisability in sub-Saharan Africa. We critically appraise evidence for associations between retina and brain neurovasculature in health and disease, and in the process we develop new hypotheses about why these vascular beds are susceptible to sequestration of parasitized erythrocytes
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