49 research outputs found

    Acute high-intensity interval rowing increases thrombin generation in healthy men

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    PURPOSE: High-intensity exercise induces several health benefits, but may acutely and transiently increase the risk of cardiovascular events due to thrombotic changes promoting blood coagulation and thrombin formation. This study examined the effects of high-intensity exercise on plasma thrombin generation and triacylglycerol concentrations. METHODS: Sixteen healthy men completed two, 2-day conditions separated by 1 week. On day 1, participants rested (control) or completed four, 3-min high-intensity rowing intervals at an average rating of perceived exertion of 17 (exercise). Venous blood samples were collected pre- and post-intervention to determine plasma thrombin generation. On day 2, participants rested and consumed a glucose load (0 h) and high-fat meal (2 h). Fifteen venous blood samples were collected between 0 and 8 h to measure plasma thrombin generation and triacylglycerol concentrations. RESULTS: On day 1, lag time was shorter and peak thrombin and endogenous thrombin potential were greater in the exercise than control condition (ES ≄ 0.37, main effect condition P ≀ 0.03), and post-intervention compared with pre-intervention (ES ≄ 0.49, main effect time P ≀ 0.003). The magnitude of the post-intervention change was greater in the exercise than control condition for all thrombin generation parameters (condition by time interaction P ≀ 0.05). On day 2, no differences in postprandial thrombin generation parameters were seen between conditions (P ≄ 0.21). The total area under the curve for triacylglycerol was lower in the exercise than control condition (ES = 0.34, P = 0.02). CONCLUSION: An acute bout of high-intensity interval rowing increased plasma thrombin generation immediately after exercise, but these differences were eliminated 16–24 h after exercise

    Clinical implementation of a knowledge based planning tool for prostate VMAT

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    Abstract Background A knowledge based planning tool has been developed and implemented for prostate VMAT radiotherapy plans providing a target average rectum dose value based on previously achievable values for similar rectum/PTV overlap. The purpose of this planning tool is to highlight sub-optimal clinical plans and to improve plan quality and consistency. Methods A historical cohort of 97 VMAT prostate plans was interrogated using a RayStation script and used to develop a local model for predicting optimum average rectum dose based on individual anatomy. A preliminary validation study was performed whereby historical plans identified as “optimal” and “sub-optimal” by the local model were replanned in a blinded study by four experienced planners and compared to the original clinical plan to assess whether any improvement in rectum dose was observed. The predictive model was then incorporated into a RayStation script and used as part of the clinical planning process. Planners were asked to use the script during planning to provide a patient specific prediction for optimum average rectum dose and to optimise the plan accordingly. Results Plans identified as “sub-optimal” in the validation study observed a statistically significant improvement in average rectum dose compared to the clinical plan when replanned whereas plans that were identified as “optimal” observed no improvement when replanned. This provided confidence that the local model can identify plans that were suboptimal in terms of rectal sparing. Clinical implementation of the knowledge based planning tool reduced the population-averaged mean rectum dose by 5.6Gy. There was a small but statistically significant increase in total MU and femoral head dose and a reduction in conformity index. These did not affect the clinical acceptability of the plans and no significant changes to other plan quality metrics were observed. Conclusions The knowledge-based planning tool has enabled substantial reductions in population-averaged mean rectum dose for prostate VMAT patients. This suggests plans are improved when planners receive quantitative feedback on plan quality against historical data

    The genetic architecture of membranous nephropathy and its potential to improve non-invasive diagnosis

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    Membranous Nephropathy (MN) is a rare autoimmune cause of kidney failure. Here we report a genome-wide association study (GWAS) for primary MN in 3,782 cases and 9,038 controls of East Asian and European ancestries. We discover two previously unreported loci, NFKB1 (ï»żrs230540, OR = 1.25, P = 3.4 × 10-12) and IRF4 (ï»żrs9405192, OR = 1.29, P = ï»ż1.4 × 10-14), fine-map the PLA2R1 locus (ï»żrs17831251, OR = 2.25, P = 4.7 × 10-103) and report ancestry-specific effects of three classical HLA alleles: DRB1*1501 in East Asians (OR = 3.81, P = 2.0 × 10-49), DQA1*0501 in Europeans (OR = 2.88, P = 5.7 × 10-93), and DRB1*0301 in both ethnicities (OR = 3.50, P = 9.2 × 10-23 and OR = 3.39, P = 5.2 × 10-82, respectively). GWAS loci explain 32% of disease risk in East Asians and 25% in Europeans, and correctly re-classify 20-37% of the cases in validation cohorts that are antibody-negative by the serum anti-PLA2R ELISA diagnostic test. Our findings highlight an unusual genetic architecture of MN, with four loci and their interactions accounting for nearly one-third of the disease risk

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

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    Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≀ 18 years: 69, 48, 23; 85%), older adults (≄ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

    Metabolite changes in HT-29 xenograft tumors following HIF-1 alpha inhibition with PX-478 as studied by MR spectroscopy in vivo and ex vivo

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    The hypoxia-inducible transcription factor (HIF-1 alpha) plays a central role in tumor development. PX-478 is an experimental anti-cancer drug known to inhibit HIF-1 alpha in experimental tumors. The purpose of this study was to identify MRS-visible metabolic biomarkers for PX-478 response prior to phase I/II clinical trials. Single-voxel in vivo localized H-1 spectra were obtained from HT-29 tumor xenografts prior and up to 24 h after treatment with a single dose of PX-478. Profiles of water-soluble and lipophilic metabolites were also examined ex vivo with both H-1 and P-31 spectroscopy for peak identification and to interrogate the underlying biochemistry of the response. The total choline (tCho) resonance was significantly decreased in vivo 12 and 24 h following treatment with PX-478 and this was confirmed with high-resolution 1 H and P-31 MRS. In non-aqueous extracts, significant reductions in cardiolipin, PtdEtn (phosphatidylethanolamine) and PtdI (phosphatidylinositol) were seen in response to PX-478. Although there were trends to a decrease in lactate (and lipid) resonances in vivo and ex vivo, these changes were not significant. This is in contrast to inhibition of in vitro glucose consumption and lactate production by PX-478 in HT-29 cells. The significant and robust change in tCho has identified this as a potential 1H MRS-visible biomarker for drug response in vivo while high-resolution spectroscopy indicated that GPC, PC, myol, PE, GPE, CL, PtdEtn and Ptdl are potential ex vivo response biomarkers. Copyright (c) 2005 John Wiley & Sons, Ltd

    Dynamic contrast-enhanced and diffusion MRI show rapid and dramatic changes in tumor microenvironment in response to inhibition of HIF-1 alpha using PX-478

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    PX-478 is a new agent known to inhibit the hypoxia-responsive transcription factor, HIF-1 alpha, in experimental tumors. The current study was undertaken in preparation for clinical trials to determine which noninvasive imaging endpoint(s) is sensitive to this drug's actions. Dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance imaging (MRI) were used to monitor acute effects on tumor hemodynamics and cellularity, respectively. Mice bearing human xenografts were treated either with PX-478 or vehicle, and imaged over time. DW imaging was performed at three b values to generate apparent diffusion coefficient of water (ADCw) maps. For DCE-MRI, a macromolecular contrast reagent, BSA-Gd-DTPA, was used to determine vascular permeability and vascular volume fractions. PX-478 induced a dramatic reduction in tumor blood vessel permeability within 2 hours after treatment, which returned to baseline by 48 hours. The anti-VEGF antibody, Avastin, reduced both the permeability and vascular volume. PX-478 had no effect on the perfusion behavior of a drug-resistant tumor system, A-549. Tumor cellularity, estimated from ADCw, was significantly decreased 24 and 36 hours after treatment. This is the earliest significant response of ADC to therapy yet reported. Based on these preclinical findings, both of these imaging endpoints will be included in the clinical trial of PX-478
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