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Physiological variability in pancreatic cell type gene regulation and the impact on diabetes risk is poorly understood. In this study we mapped gene regulation in pancreatic cell types using single cell multiomic (joint RNA-seq and ATAC-seq) profiling in 28 non-diabetic donors in combination with single cell data from 35 non-diabetic donors in the Human Pancreas Analysis Program. We identified widespread associations with age, sex, BMI, and HbA1c, where gene regulatory responses were highly cell type- and phenotype-specific. In beta cells, donor age associated with hypoxia, apoptosis, unfolded protein response, and external signal-dependent transcriptional regulators, while HbA1c associated with inflammatory responses and gender with chromatin organization. We identified 10.8K loci where genetic variants were QTLs for cis regulatory element (cRE) accessibility, including 20% with lineage- or cell type-specific effects which disrupted distinct transcription factor motifs. Type 2 diabetes and glycemic trait associated variants were enriched in both phenotype- and QTL-associated beta cell cREs, whereas type 1 diabetes showed limited enrichment. Variants at 226 diabetes and glycemic trait loci were QTLs in beta and other cell types, including 40 that were statistically colocalized, and annotating target genes of colocalized QTLs revealed genes with putatively novel roles in disease. Our findings reveal diverse responses of pancreatic cell types to phenotype and genotype in physiology, and identify pathways, networks, and genes through which physiology impacts diabetes risk.
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OBJECTIVE: A multi-national high-volume center study was undertaken to evaluate outcomes after primary surgery (PS) or neoadjuvant treatment followed by surgery (NAT/S) in cT2 staged adenocarcinomas of the esophagus (EAC) and gastroesophageal junction (GEJ). BACKGROUND: Optimal treatment approach with either NAT/S or PS for clinically staged cT2cNany or cT2N0 EAC and GEJ remains unknown due to the lack of randomized controlled trials. METHODS: Retrospective analysis of prospectively maintained databases from ten centers was performed. Between 01/2012-08/2023 645 patients who fulfilled inclusion criteria of GEJ Siewert type I, II or EAC with cT2 status at diagnosis underwent PS or NAT/S with curative intent. Primary endpoint was overall survival (OS). RESULTS: In the cT2cNany cohort 192 patients (29.8%) underwent PS and 453 (70.2%) underwent NAT/S. In all cT2cN0 patients (n=333), NAT/s remained the more frequent treatment (56.2%). Patients undergoing PS were in both cT2 cohorts older (P<0.001) and had a higher ASA classification (P<0.05). R0 resection showed no differences between NAT/S and PS in both cT2 cohorts (P>0.4).Median OS was 51.0 months in the PS group (95% CI 31.6-70.4) versus 114.0 months (95% CI 53.9-174.1) in the NAT/S group (P=0.003) of cT2cNany patients. For cT2cN0 patients NAT/S was associated with longer OS (P=0.002) and disease-free survival (DFS) (P=0.001). After propensity score matching of cT2N0 patients, survival benefit for NAT/S remained (P=0.004). Histopathology showed that 38.1% of cT2cNany and 34.2% of cT2cN0 patients were understaged. CONCLUSIONS: Due to unreliable identification of cT2N0 disease, all patients should be offered a multimodal therapeutic approach.
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BACKGROUND: Oesophageal, gastroesophageal, and gastric malignancies are often diagnosed at locally advanced stage and multimodal therapy is recommended to increase the chances of survival. However, given the significant variation in treatment response, there is a clear imperative to refine patient stratification. The aim of this narrative review was to explore the existing evidence and the potential of radiomics to improve staging and prediction of treatment response of oesogastric cancers. METHODS: The references for this review article were identified via MEDLINE (PubMed) and Scopus searches with the terms "radiomics", "texture analysis", "oesophageal cancer", "gastroesophageal junction cancer", "oesophagogastric junction cancer", "gastric cancer", "stomach cancer", "staging", and "treatment response" until May 2024. RESULTS: Radiomics proved to be effective in improving disease staging and prediction of treatment response for both oesophageal and gastric cancer with all imaging modalities (TC, MRI, and 18F-FDG PET/CT). The literature data on the application of radiomics to gastroesophageal junction cancer are very scarce. Radiomics models perform better when integrating different imaging modalities compared to a single radiology method and when combining clinical to radiomics features compared to only a radiomics signature. CONCLUSIONS: Radiomics shows potential in noninvasive staging and predicting response to preoperative therapy among patients with locally advanced oesogastric cancer. As a future perspective, the incorporation of molecular subgroup analysis to clinical and radiomic features may even increase the effectiveness of these predictive and prognostic models.
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OBJECTIVE/BACKGROUND: Various anastomotic and reconstruction techniques are used for minimally invasive total (miTG) and distal gastrectomy (miDG). Their effects on postoperative morbidity have not been extensively studied. METHODS: MiTG and miDG patients were selected from 9356 oncological gastrectomies performed 2017-2021 in 44 centers. Endpoints included anastomotic leakage (AL) rate and postoperative morbidity tested by multivariable analysis. RESULTS: Three major anastomotic techniques (circular stapled (CS); linear stapled (LS); hand sewn (HS)), and three major bowel reconstruction types (Roux (RX); Billroth I (BI); Billroth II (BII)) were identified in miTG (n=878) and miDG (n=3334). Postoperative complications including AL (5.2% vs. 1.1%), overall (28.7% vs. 16.3%) and major morbidity (15.7% vs. 8.2%), as well as 90-day mortality (1.6% vs. 0.5%) were higher after miTG compared with miDG. After miTG, AL rate was higher after CS (4.3%) and HS (7.9%) compared with LS (3.4%). Similarly, major complications (LS: 9.7%, CS: 16.2%, HS: 12.7%) were lowest after LS. Multivariate analysis confirmed anastomotic technique as predictive factor for AL, overall and major complications. In miDG, AL rate (BI: 1.4%, BII 0.8%, RX 1.2%), overall (BI: 14.5%, BII: 15.0%, RX: 18.7%,) and major morbidity (BI: 7.9%, BII: 9.1%, RX: 7.2%), and mortality (BI: 0%, BII: 0.1%, RY: 1.1%%) were not affected by bowel reconstruction. CONCLUSION: In oncologically suitable situations, miDG should be preferred to miTG, as postoperative morbidity is significantly lower. LS should be a preferred anastomotic technique for miTG in Western Centers. Conversely, bowel reconstruction in DG may be chosen according to surgeon's preference.
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Application of the physical laws of energy and mass conservation at the whole-body level is not necessarily informative about causal mechanisms of weight gain and the development of obesity. The energy balance model (EBM) and the carbohydrate-insulin model (CIM) are two plausible theories, among several others, attempting to explain why obesity develops within an overall common physiological framework of regulation of human energy metabolism. These models have been used to explain the pathogenesis of obesity in individuals as well as the dramatic increases in the prevalence of obesity worldwide over the past half century. Here, we summarize outcomes of a recent workshop in Copenhagen that brought together obesity experts from around the world to discuss causal models of obesity pathogenesis. These discussions helped to operationally define commonly used terms; delineate the structure of each model, particularly focussing on areas of overlap and divergence; challenge ideas about the importance of purported causal factors for weight gain; and brainstorm on the key scientific questions that need to be answered. We hope that more experimental research in nutrition and other related fields, and more testing of the models and their predictions will pave the way and provide more answers about the pathogenesis of obesity than those currently available.
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BACKGROUND: Antenatal steroid therapy for fetal lung maturation is routinely administered to women at risk of preterm delivery. There is strong evidence to demonstrate benefit from antenatal steroids in terms of survival and respiratory disease, notably in infants delivered at or below 32 weeks' gestation. However, dosing remains unoptimized and lung benefits are highly variable. Current treatment regimens generate high-concentration, pulsatile fetal steroid exposures now associated with increased risk of childhood neurodevelopmental diseases. We hypothesized that damage-associated changes in the fetal hippocampal transcriptome would be independent of preterm lung function. METHODS: Date-mated ewes carrying a single fetus at 122 ± 2dGA (term = 150dGA) were randomized into 4 groups: (i) Saline Control Group, 4×2ml maternal saline intramuscular(IM) injections at 12hr intervals (n = 11); or (ii) Dex High Group, 2×12mg maternal IM dexamethasone phosphate injections at 12hr intervals followed by 2×2ml IM saline injections at 12hr intervals (n = 12; representing a clinical regimen used in Singapore); or (iii) Dex Low Group, 4×1.5mg maternal IM dexamethasone phosphate injections 12hr intervals (n = 12); or (iv) Beta-Acetate Group, 1×0.125mg/kg maternal IM betamethasone acetate injection followed by 3×2ml IM sterile normal saline injections 12hr intervals (n = 8). Lambs were surgically delivered 48hr after first maternal injection at 122-125dGA, ventilated for 30min to establish lung function, and euthanised for necropsy and tissue collection. RESULTS: Preterm lambs from the Dex Low and Beta-Acetate Groups had statistically and biologically significant lung function improvements (measured by gas exchange, lung compliance). Compared to the Saline Control Group, hippocampal transcriptomic data identified 879 differentially significant expressed genes (at least 1.5-fold change and FDR < 5%) in the steroid-treated groups. Pulsatile dexamethasone-only exposed groups (Dex High and Dex Low) had three common positively enriched differentially expressed pathways related in part to neurodegeneration ("Prion Disease", "Alzheimer's Disease", "Arachidonic Acid metabolism"). Adverse changes were independent of respiratory function during ventilation. CONCLUSIONS: Our data suggests that exposure to antenatal steroid therapy is an independent cause of damage- associated transcriptomic changes in the brain of preterm, fetal sheep. These data highlight an urgent need for careful reconsideration and balancing of how antenatal steroids are used, both for patient selection and dosing regimens.
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Hipocampo , Pulmón , Animales , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Ovinos , Femenino , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Embarazo , Dexametasona/farmacología , Betametasona/administración & dosificación , Feto/efectos de los fármacosRESUMEN
OBJECTIVES: Emergent vascular imaging identifies a subset of patients requiring immediate specialized care (i.e. carotid stenosis > 50%, dissection or free-floating thrombus). However, most TIA patients do not have these findings, so it is inefficient to image all TIA patients in crowded emergency departments (ED). Our objectives were to derive and internally validate a clinical prediction score for clinically significant carotid artery disease in TIA patients. METHODS: This was a planned secondary analysis of a prospective cohort study from 14 Canadian EDs. Among 11555 consecutive adult ED patients with TIA/minor stroke symptoms over 12 years, 9882 had vascular imaging and were included in the analysis. Our main outcome was clinically significant carotid artery disease, defined as extracranial internal carotid stenosis ≥ 50%, dissection, or thrombus in the internal carotid artery, with contralateral symptoms. RESULTS: Of 9882 patients, 888 (9.0%) had clinically significant carotid artery disease. Logistic regression was used to derive a 13-variable reduced model. We simplified the model into a score (Symcard [Symptomatic carotid artery disease] Score), with suggested cut-points for high, medium, and low-risk stratification. A substantial portion (38%) of patients were classified as low-risk, 33.8% as medium risk, and 28.2% as high risk. At the low-risk cut-point, sensitivity was 92.9%, specificity 41.1%, and diagnostic yield 1.7%. CONCLUSIONS: This simple score can predict carotid artery disease in TIA patients using readily available information. It identifies low-risk patients who can defer vascular imaging to an outpatient or specialty clinic setting. Medium-risk patients may undergo imaging immediately or with slight delay, depending on local resources. High-risk patients should undergo urgent vascular imaging.
RéSUMé: OBJECTIFS: L'imagerie vasculaire émergente permet d'identifier un sous-ensemble de patients nécessitant des soins spécialisés immédiats (c.-à-d. sténose carotidienne >50 %, dissection ou thrombus flottant). Cependant, la plupart des patients atteints de RTI ne présentent pas ces résultats, il est donc inefficace d'effectuer une imagerie de tous les patients atteints de RTI dans les services d'urgence (ER) surpeuplés. Nos objectifs étaient de calculer et de valider en interne un score de prédiction clinique pour la maladie carotide cliniquement significative chez les patients atteints d'une AIT MéTHODES: Il s'agissait d'une analyse secondaire planifiée d'une étude de cohorte prospective menée auprès de 14 DE canadiens. Parmi les 11555 patients adultes consécutifs atteints d'un EI présentant des symptômes d'AIT/AVC mineur au cours des 12 dernières années, 9882 ont reçu une imagerie vasculaire et ont été inclus dans l'analyse. Notre principal critère de jugement était la maladie carotide cliniquement significative, définie comme une sténose extracrânienne de la carotide interne à 50 %, une dissection ou un thrombus dans l'artère carotide interne, avec des symptômes contralatéraux. RéSULTATS: Sur 9882 patients, 888 (9,0 %) présentaient une maladie de l'artère carotide cliniquement significative. La régression logistique a été utilisée pour obtenir un modèle réduit à 13 variables. Nous avons simplifié le modèle en un score (Symcard [Symptomatic carotid artery disease] Score), avec des points de coupure suggérés pour la stratification à risque élevé, moyen et faible. Une proportion importante (38,0 %) des patients ont été classés à faible risque, 33,8 % à risque moyen et 28,2 % à risque élevé. Au seuil de faible risque, la sensibilité était de 92,9 %, la spécificité de 41,1 % et le rendement diagnostique de 1,7 %. CONCLUSIONS: Ce score simple permet de prédire la maladie de l'artère carotide chez les patients atteints d'AIT en utilisant des informations facilement disponibles. Il identifie les patients à faible risque qui peuvent reporter l'imagerie vasculaire à un établissement de consultation externe ou de spécialité. Les patients à risque moyen peuvent subir une imagerie immédiatement ou avec un léger délai, selon les ressources locales. Les patients à haut risque doivent subir une imagerie vasculaire urgente.
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BACKGROUND: Diagnostic uncertainty exists surrounding the identification of radiographic pneumonia in children with wheeze. It is important to determine the prevalence and clinical predictors of pneumonia in this population to limit chest radiography (CXR) and promote judicious antibiotic use. OBJECTIVES: The objectives were to (1) estimate the prevalence of radiographic pneumonia in children with wheeze and (2) systematically review the diagnostic accuracy of clinical findings for the identification of radiographic pneumonia. METHODS: Data sources were MEDLINE, PubMed Central, Cochrane Library, CINAHL, and Web of Science (January 1995 to September 2023). For study selection, two reviewers identified high-quality studies reporting on clinical characteristics associated with radiographic pneumonia in wheezing children (age 0-21 years). Using Covidence software, data regarding study characteristics, methodologic quality, and results were extracted. Data were pooled using random-effects meta-analysis. RESULTS: A total of 8333 unique titles and abstracts were reviewed. Twelve studies, representing 7398 patients, were included. Fifteen percent of children with wheeze undergoing CXR had pneumonia. Findings associated with radiographic pneumonia included temperature ≥ 38.4°C (positive likelihood ratio [LR+] 2.1, 95% CI 1.2-3.6, specificity 85%), oxygen saturation < 92% (LR+ 3.6, 95% CI 1.4-8.9, specificity 89%), and grunting (LR+ 2.7, 95% CI 1.6-4.4, pooled specificity 91%). Factors associated with the absence of radiographic pneumonia included lack of fever (negative likelihood ratio [LR-] 0.67, 95% CI 0.52-0.85) and oxygen saturation ≥ 95% (LR- 0.64, 95% CI 0.42-0.98). Tachypnea and auscultatory findings were not associated with radiographic pneumonia. DISCUSSION: Heterogeneity across studies limits generalizability. Additionally, all included studies overestimate the rate of radiographic pneumonia given the fact that all subjects had a CXR performed due to clinical suspicion of pneumonia. CONCLUSIONS: Radiographic pneumonia occurs in 15% of wheezing children undergoing CXR for pneumonia. Auscultatory findings and tachypnea do not differentiate children with and without pneumonia, and the rate of radiographic pneumonia is very low in the absence of fever and hypoxemia.
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The potential for unintended drug induced changes in cardiac contractility is a major concern in medicines development. Whilst direct left ventricular pressure (LVP) measurement is the gold standard for measuring cardiac contractility in vivo, it is resource intensive and poses a welfare burden on research animals. In contrast, arterial blood pressure (BP) measurement has fewer challenges. Symmetric Projection Attractor Reconstruction (SPAR) is a signal processing technique which transforms physiological time-series signals into a corresponding visual image ('attractor'), amplifying morphology changes within physiological waveforms. It was hypothesized that SPAR analysis of BP signals would provide a surrogate measure of cardiac contractility by specifically amplifying the maximum slope of the systolic upstroke. BP (abdominal aorta) signals obtained from beagle dogs, treated with positive and negative inotropes, were retrospectively analysed to identify signal features that correlated with the maximum upslope of the LVP signal from simultaneously acquired LVP recordings. SPAR transformation of BP signals quantified drug induced changes in the maximum slope of the systolic upstroke. We identified key SPAR metrics that provided >0.8 correlation with the LVP maximum upslope, outperforming the BP systolic upstroke alone. This was observed for all 4 different drugs, doses and time points evaluated across studies. Thus, we conclude that the SPAR measures derived from the BP signal could be used as a first pass in vivo screen to flag any risk of drug induced changes in cardiac contractility during the conduct of non-clinical medicines development, potentially reducing or replacing the need to perform direct left ventricular measurements.
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INTRODUCTION: Gastroesophageal cancer patients' information needs remain understudied, despite their complex treatment trajectories. METHODS: This study examined the (i) information needs of patients with or without postoperative complications, (ii) information needs of male and female patients, and (iii) the association between information needs and health-related quality of life (HR-QoL) following gastroesophageal cancer surgery. Patients completed the EORTC-QLQ-INFO25, QLQ-C30, and QLQ-OG25 questionnaires before and after curative surgery. Five information needs domains were investigated: information about the disease, about treatments, about medical tests, about things patients can do to help themselves, and overall helpfulness. Additionally, HR-QoL domains global health status, eating restrictions, and anxiety were explored. RESULTS: A total of 132 patients completed the questionnaires at baseline, 216 patients at 6-12 months, 184 patients at 18-24 months, and 163 patients at 3-5 years post-operation. There were no significant differences in information needs between patients with or without complications or between male and female patients. Patients with a higher global health status found the information more helpful at 6-12 months (p < 0.001), 18-24 months (p < 0.001), and 3-5 years (p < 0.001) postoperatively, as did patients who experienced more anxiety at 18-24 months (p = 0.009) and 3-5 years (p < 0.001). CONCLUSION: Gastroesophageal cancer patients, regardless of sex or postoperative complications, have consistent information needs, yet those with higher global health status and elevated anxiety levels find the information particularly helpful, emphasizing the importance of tailored communication strategies.
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Non-alcoholic fatty liver disease (NAFLD) is a progressive liver disease, affecting 38% of adults globally. If left untreated, NAFLD may progress to more advanced forms of the disease, including non-alcoholic steatohepatitis (NASH), liver cirrhosis, and fibrosis. Early NAFLD detection is critical to prevent disease progression. Using an obesogenic high-fat and high-sucrose (HF/HS) diet, we characterized the progression of NAFLD in male and female Collaborative Cross CC042 mice after 20-, 40-, and 60-week intervals of chronic HF/HS diet feeding. The incidence and severity of liver steatosis, inflammation, and fibrosis increased in both sexes over time, with male mice progressing to a NASH-like disease state faster than female mice, as indicated by earlier and more pronounced changes in liver steatosis. Histopathological indication of macrovesicular steatosis and gene expression changes of key lipid metabolism genes were found to be elevated in both sexes after 20 weeks of HF/HS diet. Measurement of circulating markers of inflammation (CXCL10 and TNF-α), histopathological analysis of immune cell infiltrates, and gene expression changes in inflammation-related genes indicated significant liver inflammation after 40 and 60 weeks of HF/HS diet exposure in both sexes. Liver fibrosis, as assessed by Picosirius red and Masson's trichrome staining and changes in expression of key fibrosis related genes indicated significant changes after 40 and 60 weeks of HF/HS diet exposure. In conclusion, we present a preclinical animal model of dietary NAFLD progression, which recapitulates human pathophysiological and pathomorphological changes, that could be used to better understand the progression of NAFLD and support development of new therapeutics.
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Discerning the mechanisms driving type 2 diabetes (T2D) pathophysiology from genome-wide association studies (GWAS) remains a challenge. To this end, we integrated omics information from 16 multi-tissue and multi-ancestry expression, protein, and metabolite quantitative trait loci (QTL) studies and 46 multi-ancestry GWAS for T2D-related traits with the largest, most ancestrally diverse T2D GWAS to date. Of the 1,289 T2D GWAS index variants, 716 (56%) demonstrated strong evidence of colocalization with a molecular or T2D-related trait, implicating 657 cis-effector genes, 1,691 distal-effector genes, 731 metabolites, and 43 T2D-related traits. We identified 773 of these cis- and distal-effector genes using either expression QTL data from understudied ancestry groups or inclusion of T2D index variants enriched in underrepresented populations, emphasizing the value of increasing population diversity in functional mapping. Linking these variants, genes, metabolites, and traits into a network, we elucidated mechanisms through which T2D-associated variation may impact disease risk. Finally, we showed that drugs targeting effector proteins were enriched in those approved to treat T2D, highlighting the potential of these results to prioritize drug targets for T2D. These results represent a leap in the molecular characterization of T2D-associated genetic variation and will aid in translating genetic findings into novel therapeutic strategies.
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Background: The Antimicrobial Resistance Laboratory Network (AR Lab Network) was developed by the CDC to detect emerging antimicrobial-resistant (AR) threats and prevent outbreaks. However, low submission rates of AR isolates limit the potential of the AR Lab Network to address antimicrobial resistance (AMR). Aim: The aim of this study was to investigate barriers to submission of AR isolates in acute care hospitals (ACHs) and critical access hospitals (CAHs) within Texas Public Health Region 8 (PHR8) counties. Methods: A survey was designed and emailed to laboratory professionals to identify barriers to AR isolate submission. Responses were analyzed using 2-sided Fisher's exact tests to identify associations between responses and respondent characteristics. Results: Of the 33 hospitals within PHR8 invited to participate in the survey, responses were received from 21, a response rate of 63.6%. Lack of awareness of the AR Lab Network was the most frequently cited barrier to submission (65.4% of respondents). Other reported barriers to submission included lack of laboratory staff time (57.7%), lack of training with the submission process (34.6%), lack of personnel certified to ship infectious substances (23.1%), and lack of laboratory/shipping supplies (23.1%). Discussion: Regardless of the respondent's role, time in that role, or type of hospital in which they worked, the most common barrier to isolate submission was lack of awareness of the AR Lab Network. In the future, we will address the identified barriers by implementing educational outreach programs about AMR and the AR Lab Network for hospitals and other healthcare facilities within PHR8.
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BACKGROUND: It is unknown which factors are associated with chest radiograph (CXR) and antibiotic use for suspected community-acquired pneumonia (CAP) in children. We evaluated factors associated with CXR and antibiotic preferences among clinicians for children with suspected CAP using case scenarios generated through artificial intelligence (AI). METHODS: We performed a survey of general pediatric, pediatric emergency medicine, and emergency medicine attending physicians employed by a private physician contractor. Respondents were given 5 unique, AI-generated case scenarios. We used generalized estimating equations to identify factors associated with CXR and antibiotic use. We evaluated the cluster-weighted correlation between clinician suspicion and clinical prediction model risk estimates for CAP using 2 predictive models. RESULTS: A total of 172 respondents provided responses to 839 scenarios. Factors associated with CXR acquisition (OR, [95% CI]) included presence of crackles (4.17 [2.19, 7.95]), prior pneumonia (2.38 [1.32, 4.20]), chest pain (1.90 [1.18, 3.05]) and fever (1.82 [1.32, 2.52]). The decision to use antibiotics before knowledge of CXR results included past hospitalization for pneumonia (4.24 [1.88, 9.57]), focal decreased breath sounds (3.86 [1.98, 7.52]), and crackles (3.45 [2.15, 5.53]). After revealing CXR results to clinicians, these results were the sole predictor associated with antibiotic decision-making. Suspicion for CAP correlated with one of 2 prediction models for CAP (Spearman's rho = 0.25). Factors associated with a greater suspicion of pneumonia included prior pneumonia, duration of illness, worsening course of illness, shortness of breath, vomiting, decreased oral intake or urinary output, respiratory distress, head nodding, focal decreased breath sounds, focal rhonchi, fever, and crackles, and lower pulse oximetry. CONCLUSIONS: Ordering preferences for CXRs demonstrated similarities and differences with evidence-based risk models for CAP. Clinicians relied heavily on CXR findings to guide antibiotic ordering. These findings can be used within decision support systems to promote evidence-based management practices for pediatric CAP.
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Our understanding of the pathophysiology of obesity remains at best incomplete despite a century of research. During this time, two alternative perspectives have helped shape thinking about the etiology of the disorder. The currently prevailing view holds that excessive fat accumulation results because energy intake exceeds energy expenditure, with excessive food consumption being the primary cause of the imbalance. The other perspective attributes the initiating cause of obesity to intrinsic metabolic defects that shift fuel partitioning from pathways for mobilization and oxidation to those for synthesis and storage. The resulting reduction in fuel oxidation and trapping of energy in adipose tissue drives a compensatory increase in energy intake and, under some conditions, a decrease in expenditure. This theory of obesity pathogenesis has historically garnered relatively less attention despite its pedigree. Here, we present an updated comprehensive formulation of the fuel partitioning theory, focused on evidence gathered over the last 80 years from major animal models of obesity showing a redirection of fuel fluxes from oxidation to storage and accumulation of excess body fat with energy intake equal to or even less than that of lean animals. The aim is to inform current discussions about the etiology of obesity and by so doing, help lay new foundations for the design of more efficacious approaches to obesity research, treatment and prevention.
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Diabetic nephropathy (DN) is a major healthcare challenge for individuals with diabetes and associated with increased cardiovascular morbidity and mortality. The existing rodent models do not fully represent the complex course of the human disease. Hence, developing a translational model of diabetes that reproduces both the early and the advanced characteristics of DN and faithfully recapitulates the overall human pathology is an unmet need. Here, we introduce the Nile grass rat (NGR) as a novel model of DN and characterize key pathologies underlying DN. NGRs spontaneously developed insulin resistance, reactive hyperinsulinemia, and hyperglycemia. Diabetic NGRs evolved DN and the key histopathological aspects of the human advanced DN, including glomerular hypertrophy, infiltration of mononuclear cells, tubular dilatation, and atrophy. Enlargement of the glomerular tufts and the Bowman's capsule areas accompanied the expansion of the Bowman's space. Glomerular sclerosis, renal arteriolar hyalinosis, Kimmelsteil-Wilson nodular lesions, and protein cast formations in the kidneys of diabetic NGR occurred with DN. Diabetic kidneys displayed interstitial and glomerular fibrosis, key characteristics of late human pathology as well as thickening of the glomerular basement membrane and podocyte effacement. Signs of injury included glomerular lipid accumulation, significantly more apoptotic cells, and expression of KIM-1. Diabetic NGRs became hypertensive, a known risk factor for kidney dysfunction, and showed decreased glomerular filtration rate. Diabetic NGRs recapitulate the breadth of human DN pathology and reproduce the consequences of chronic kidney disease, including injury and loss of function of the kidney. Hence, NGR represents a robust model for studying DN-related complications and provides a new foundation for more detailed mechanistic studies of the genesis of nephropathy, and the development of new therapeutic approaches.
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Nefropatías Diabéticas , Modelos Animales de Enfermedad , Animales , Nefropatías Diabéticas/patología , Nefropatías Diabéticas/metabolismo , Ratas , Masculino , Humanos , Resistencia a la Insulina , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/complicaciones , Riñón/patología , Riñón/metabolismo , Glomérulos Renales/patología , Glomérulos Renales/metabolismoRESUMEN
The reaction of Re(CO)5Br with deprotonated 1H-(5-(2,2':6',2''-terpyridine)pyrid-2-yl)tetrazole yields a triangular assembly formed by tricarbonyl Re(I) vertices. Photophysical measurements reveal blue-green emission with a maximum at 520â nm, 32 % quantum yield, and 2430â ns long-lived excited state decay lifetime in deaerated dichloromethane solution. Coordination of lanthanoid ions to the terpyridine units red-shifts the emission to 570â nm and also reveals efficient (90 %) and fast sensitisation of both Eu(III) and Yb(III) at room temperature, with a similar rate constant kET on the order of 107â s-1. Efficient sensitisation of Eu(III) from Re(I) is unprecedented, especially when considering the close proximity in energy between the donor and acceptor excited states. On the other hand, comparative measurements at 77â K reveal that energy transfer to Yb(III) is two orders of magnitude slower than that to Eu(III). A two-step mechanism of sensitisation is therefore proposed, whereby the rate-determining step is a thermally activated energy transfer step between the Re(I) centre and the terpyridine functionality, followed by rapid energy transfer to the respective Ln(III) excited states. At 77â K, the direct Re(I) to Eu(III) energy transfer seems to proceed via a ligand-mediated superexchange Dexter-type mechanism.
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PtdIns and its phosphorylated derivatives, the phosphoinositides, are the biochemical components of a major pathway of intracellular signaling in all eukaryotic cells. These lipids are few in terms of cohort of unique positional isomers, and are quantitatively minor species of the bulk cellular lipidome. Nevertheless, phosphoinositides regulate an impressively diverse set of biological processes. It is from that perspective that perturbations in phosphoinositide-dependent signaling pathways are increasingly being recognized as causal foundations of many human diseases - including cancer. Although phosphatidylinositol transfer proteins (PITPs) are not enzymes, these proteins are physiologically significant regulators of phosphoinositide signaling. As such, PITPs are conserved throughout the eukaryotic kingdom. Their biological importance notwithstanding, PITPs remain understudied. Herein, we review current information regarding PITP biology primarily focusing on how derangements in PITP function disrupt key signaling/developmental pathways and are associated with a growing list of pathologies in mammals.