380 research outputs found

    Comparing the interobserver reproducibility of different regions of interest on multi-parametric renal magnetic resonance imaging in healthy volunteers, patients with heart failure and renal transplant recipients

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    Objective: To assess interobserver reproducibility of different regions of interest (ROIs) on multi-parametric renal MRI using commercially available software. Materials and methods: Healthy volunteers (HV), patients with heart failure (HF) and renal transplant recipients (Tx) were recruited. Localiser scans, T1 mapping and pseudo-continuous arterial spin labelling (pCASL) were performed. HV and Tx also underwent diffusion-weighted imaging to allow calculation of apparent diffusion coefficient (ADC). For T1, pCASL and ADC, ROIs were drawn for whole kidney (WK), cortex (Cx), user-defined representative cortex (rep-Cx) and medulla. Intraclass correlation coefficient (ICC) and coefficient of variation (CoV) were assessed. Results: Forty participants were included (10 HV, 10 HF and 20 Tx). The ICC for renal volume was 0.97 and CoV 6.5%. For T1 and ADC, WK, Cx, and rep-Cx were highly reproducible with ICC ≥ 0.76 and CoV < 5%. However, cortical pCASL results were more variable (ICC > 0.86, but CoV up to 14.2%). While reproducible, WK values were derived from a wide spread of data (ROI standard deviation 17% to 55% of the mean value for ADC and pCASL, respectively). Renal volume differed between groups (p < 0.001), while mean cortical T1 values were greater in Tx compared to HV (p = 0.009) and HF (p = 0.02). Medullary T1 values were also higher in Tx than HV (p = 0.03), while medullary pCASL values were significantly lower in Tx compared to HV and HF (p = 0.03 for both). Discussion: Kidney volume calculated by manually contouring a localiser scan was highly reproducible between observers and detected significant differences across patient groups. For T1, pCASL and ADC, Cx and rep-Cx ROIs are generally reproducible with advantages over WK values

    Bisphenol A exposure and cardiac electrical conduction in excised rat hearts

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    BACKGROUND: Bisphenol A (BPA) is used to produce polycarbonate plastics and epoxy resins that are widely used in everyday products, such as food and beverage containers, toys and medical devices. Human biomonitoring studies have suggested that a large proportion of the population may be exposed to BPA. Recent epidemiological studies have reported correlations between increased BPA urinary concentrations and cardiovascular disease; yet the direct effects of BPA on the heart are unknown. OBJECTIVES: The goal of our studies was to measure BPA\u27s effect (0.1-100 μM) on cardiac impulse propagation ex vivo, using excised whole hearts from adult rats. METHODS: We measured atrial and ventricular activation times during sinus and paced rhythms using epicardial electrodes and optical mapping of transmembrane potential. Atrioventricular activation intervals and epicardial conduction velocities were computed using recorded activation times. RESULTS: Cardiac BPA exposure resulted in prolonged PR segment and decreased epicardial conduction velocity (0.1 - 100 μM), prolonged action potential duration (1 - 100 μM) and delayed atrioventricular conduction (10 - 100 μM). Importantly, these effects were observed after acute exposure (≤ 15 min), underscoring the potential detrimental effects of continuous BPA exposure. The highest BPA concentration used (100 μM) resulted in prolonged QRS intervals, dropped ventricular beats and eventually resulted in complete heart block. CONCLUSIONS: Our results show that acute BPA exposure slows electrical conduction in excised hearts from female rats. These findings emphasize the importance of examining BPA\u27s effect on heart electrophysiology and determining whether chronic in vivo exposure can cause/exacerbate conduction abnormalities in patients with pre-existing heart conditions and other high-risk populations

    Evaluation of an emergency safe supply drugs and managed alcohol program in COVID-19 isolation hotel shelters for people experiencing homelessness

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    BACKGROUND: During a COVID-19 outbreak in the congregate shelter system in Halifax, Nova Scotia, Canada, a multidisciplinary health care team provided an emergency “safe supply” of pharmaceutical-grade medications and beverage-grade alcohol to facilitate isolation in COVID-19 hotel shelters for residents who are dependent on these substances. We aimed to evaluate (a) substances and dosages provided, and (b) effectiveness and safety of the program. METHODS: We retrospectively reviewed medical records of all COVID-19 isolation hotel shelter residents during May 2021. We extracted data on medication and alcohol dosages provided each day. The primary outcome was residents prematurely leaving isolation against public health orders. Adverse events included (a) overdose; (b) intoxication; and (c) diversion, selling, or sharing of medications or alcohol. RESULTS: Over 25 days, 77 isolation hotel residents were assessed (mean age 42 ± 14 years; 24% women). Sixty-two (81%) residents were provided medications, alcohol, or cigarettes. Seventeen residents (22%) received opioid agonist treatment medications (methadone, buprenorphine, or slow-release oral morphine) and 27 (35%) received hydromorphone tablets. Thirty-one (40%) residents received stimulant tablets with methylphenidate (27; 35%), dextroamphetamine (8; 10%), or lisdexamfetamine (2; 3%). Six residents (8%) received benzodiazepines. Forty-two (55%) residents received alcohol, including 41 (53%) with strong beer, three (3%) with wine, and one (1%) with hard liquor. Over 14 days in isolation, mean daily dosages increased of hydromorphone (45 ± 32 to 57 ± 42mg), methylphenidate (51 ± 28 to 77 ± 37mg), dextroamphetamine (33 ± 16 to 46 ± 13mg), and alcohol (12.3 ± 7.6 to 13.0 ± 6.9 standard drinks). Six residents (8%) left isolation prematurely, but four of those residents returned. Over 1,059 person-days in isolation, there were zero overdoses. Documented concerns regarding intoxication occurred six times (0.005 events/person-day) and medication diversion or sharing three times (0.003 events/person-day). CONCLUSIONS: An emergency safe supply and managed alcohol program, paired with housing, was associated with low rates of adverse events and high rates of successful completion of the 14-day isolation period in COVID-19 isolation hotel shelters. This supports the effectiveness and safety of emergency safe supply prescribing and managed alcohol in this setting

    Automating Spacecraft Analysis: The Era of Ontological Modeling & Simulation

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    Verification by analysis is a predicted compliance of a design to imposed requirements. The levels of performance specified by performance requirements can be related to Technical Performance Measures (TPM) in a Model-Based Systems Engineering (MBSE) environment, but engineers performing verification by analysis are not commonly versed in professional Systems Engineering (SE) techniques or modeling languages such as SysML. As the formal application of Systems Engineering (SE) results in a diminution of time, effort, and money for large-scale projects, enabling technical engineers performing verification by analysis to contribute to MBSE improvements in the course of their daily work is financially incentivized. Ontologies applied to technical analysis methodologies are shown to improve the quality of verification by analysis activities while adhering to professional organization standards such as the International Council on Systems Engineering (INCOSE) SE Handbook and the National Aeronautics and Space Administration (NASA) standard 7009A: Standard for Models and Simulations

    A pipeline to quantify serum and cerebrospinal fluid microRNAs for diagnosis and detection of relapse in paediatric malignant germ-cell tumours

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    Background:The current biomarkers alpha-fetoprotein and human chorionic gonadotropin have limited sensitivity and specificity for diagnosing malignant germ-cell tumours (GCTs). MicroRNAs (miRNAs) from the miR-371-373 and miR-302/367 clusters are overexpressed in all malignant GCTs, and some of these miRNAs show elevated serum levels at diagnosis. Here, we developed a robust technical pipeline to quantify these miRNAs in the serum and cerebrospinal fluid (CSF). The pipeline was used in samples from a cohort of exclusively paediatric patients with gonadal and extragonadal malignant GCTs, compared with appropriate tumour and non-tumour control groups.Methods:We developed a method for miRNA quantification that enabled sample adequacy assessment and reliable data normalisation. We performed qRT-PCR profiling for miR-371-373 and miR-302/367 cluster miRNAs in a total of 45 serum and CSF samples, obtained from 25 paediatric patients.Results:The exogenous non-human spike-in cel-miR-39-3p and the endogenous housekeeper miR-30b-5p were optimal for obtaining robust serum and CSF qRT-PCR quantification. A four-serum miRNA panel (miR-371a-3p, miR-372-3p, miR-373-3p and miR-367-3p): (i) showed high sensitivity/specificity for diagnosing paediatric extracranial malignant GCT; (ii) allowed early detection of relapse of a testicular mixed malignant GCT; and (iii) distinguished intracranial malignant GCT from intracranial non-GCT tumours at diagnosis, using CSF and serum samples.Conclusions:The pipeline we have developed is robust, scalable and transferable. It potentially promises to improve clinical management of paediatric (and adult) malignant GCTs
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