51628 research outputs found
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Hepatocellular Carcinoma: The interconnection of epidemiology, immunopathogenesis and treatment
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Severe Mood Disorders During Pregnancy and the Postpartum Period
Get PDFThe perinatal period is considered a time of increased risk for the development of both first-onset and recurrent severe psychiatric mood disorders. This thesis focuses on the longitudinal disease course of postpartum psychosis and bipolar disorder during this high-risk period and its implications for diagnostic classification
Understanding MRSA clonal competition within a UK hospital; the possible importance of density dependence
No full textBackground: Methicillin resistant Staphylococcus aureus (MRSA) bacteria cause serious, often healthcare-associated infections and are frequently highly resistant to diverse antibiotics. Multiple MRSA clonal complexes (CCs) have evolved independently and countries have different prevalent CCs. It is unclear when and why the dominant CC in a region may switch. Methods: We developed a mathematical deterministic model of MRSA CC competing for limited resource. The model distinguishes ‘standard MRSA’ and multidrug resistant sub-populations within each CC, allowing for resistance loss and transfer between same CC bacteria. We first analysed how dynamics of this system depend on growth-rate and resistance-potential differences between CCs, and on their resistance gene accumulation. We then fit the model to capture the longitudinal CC dynamics observed at a single UK hospital, which exemplified the UK-wide switch from mainly CC30 to mainly CC22. Results: We find that within a CC, gain and loss of resistance can allow for co-existence of sensitive and resistant sub-populations. Due to more efficient transfer of resistance at higher CC density, more drug resistance can accumulate in the population of a more prevalent CC. We show how this process of density dependent competition, together with prevalence disruption, could explain the relatively sudden switch from mainly CC30 to mainly CC22 in the UK hospital setting. Alternatively, the observed hospital dynamics could be reproduced by assuming that multidrug resistant CC22 evolved only around 2004. Conclusions: We showed how higher prevalence may advantage a CC by allowing it to acquire antimicrobial resistances more easily. Due to this density dependence in competition, dominance in an area can depend on historic contingencies; the MRSA CC that happened to be first could stay dominant because of its high prevalence advantage. This then could help explain the stability, despite frequent stochastic introductions across borders, of geographic differences in MRSA CC.</p
A qualitative content analysis of cardiovascular diseases related health information targeted at the hui minority on chinese wechat official accounts
No full textIn this study, we focus on the information available in WeChat official accounts about cardiovascular diseases (CVDs), which are a leading cause of death in China. We are particularly interested in information targeting the Chinese Hui minority people, who have a high prevalence of cardiovascular risk factors (CVRFs). Our exploratory research therefore investigates whether and how the articles on WeChat official accounts are targeted at the Hui people. We used a qualitative approach to analyze 108 articles. Two related themes emerged: descriptions of how to live a healthy life; and explanations of CVDs and CVRFs. Traditional Chinese medicine likewise surfaced from the analysis as a specific and unique theme in the Chinese social and cultural context. Despite the high prevalence of CVRFs among the Hui, none of the articles included information tailored to them.</p
Surveying the Chemical Anthropocene Chemical Imaginaries and the Politics of Defining Toxicity
No full textFaced with the non-optional acceptance of toxic chemical artifacts, the ubiquitous interweaving of chemicals in our social fabric often exists out of sight and out of mind. Yet, for many, toxic exposures signal life-changing or life-ending events, phantom threats that fail to appear as such until they become too late to mitigate. Assessments of toxicological risk consist of what Sheila Jasanoff calls “sociotechnical imaginaries,” arbitrations between calculated costs and benefits, known risks and scientifically wrought justifications of safety. Prevalent financial conflicts of interest and the socially determined hazards posed by chemical exposure suggest that chemical safety assessments and regulations are a form of postnormal science. Focusing on the histories of risk assessments of pesticides such as DDT, atrazine, PFAS, and glyphosate, this article critically reviews Michel Serres's notion of “appropriation by contamination.”</p
Distinguishing pure histopathological growth patterns of colorectal liver metastases on CT using deep learning and radiomics
No full textHistopathological growth patterns (HGPs) are independent prognosticators for colorectal liver metastases (CRLM). Currently, HGPs are determined postoperatively. In this study, we evaluated radiomics for preoperative prediction of HGPs on computed tomography (CT), and its robustness to segmentation and acquisition variations. Patients with pure HGPs [i.e. 100% desmoplastic (dHGP) or 100% replacement (rHGP)] and a CT-scan who were surgically treated at the Erasmus MC between 2003–2015 were included retrospectively. Each lesion was segmented by three clinicians and a convolutional neural network (CNN). A prediction model was created using 564 radiomics features and a combination of machine learning approaches by training on the clinician’s and testing on the unseen CNN segmentations. The intra-class correlation coefficient (ICC) was used to select features robust to segmentation variations; ComBat was used to harmonize for acquisition variations. Evaluation was performed through a 100 × random-split cross-validation. The study included 93 CRLM in 76 patients (48% dHGP; 52% rHGP). Despite substantial differences between the segmentations of the three clinicians and the CNN, the radiomics model had a mean area under the curve of 0.69. ICC-based feature selection or ComBat yielded no improvement. Concluding, the combination of a CNN for segmentation and radiomics for classification has potential for automatically distinguishing dHGPs from rHGP, and is robust to segmentation and acquisition variations. Pending further optimization, including extension to mixed HGPs, our model may serve as a preoperative addition to postoperative HGP assessment, enabling further exploitation of HGPs as a biomarker.</p
Age at natural menopause and blood pressure traits
No full textObservational studies suggest that early onset of menopause is associated with increased risk of hypertension. Whether this association is causal or due to residual confounding and/or reverse causation remains undetermined. We aimed to evaluate the observational and causal association between age at natural menopause (ANM) and blood pressure traits in Caucasian women. A cross-sectional and one-sample Mendelian randomization (MR) study was conducted in 4451 postmenopausal women from the CoLaus and Rotterdam studies. Regression models were built with observational data to study the associations of ANM with systolic and diastolic blood pressure (SBP/DBP) and hypertension. One-sample MR analysis was performed by calculating a genetic risk score of 54 ANM-related variants, previously identified in a genome-wide association study (GWAS) on ANM. In the two-sample MR analysis we used the estimates from the ANM-GWAS and association estimates from 168,575 women of the UK Biobank to evaluate ANM-related variants and their causal association with SBP and DBP. Pooled analysis from both cohorts showed that a one-year delay in menopause onset was associated with 2% (95% CI 0; 4) increased odds of having hypertension, and that early menopause was associated with lower DBP (β = −1.31, 95% CI −2.43; −0.18). While one-sample MR did not show a causal association between ANM and blood pressure traits, the two-sample MR showed a positive causal association of ANM with SBP; the last was driven by genes related to DNA damage repair. The present study does not support the hypothesis that early onset of menopause is associated with higher blood pressure. Our results suggest different ANM-related genetic pathways could differently impact blood pressure.</p