103 research outputs found

    Reconstructing promoter activity from Lux bioluminescent reporters

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    The bacterial Lux system is used as a gene expression reporter. It is fast, sensitive and non-destructive, enabling high frequency measurements. Originally developed for bacterial cells, it has also been adapted for eukaryotic cells, and can be used for whole cell biosensors, or in real time with live animals without the need for euthanasia. However, correct interpretation of bioluminescent data is limited: the bioluminescence is different from gene expression because of nonlinear molecular and enzyme dynamics of the Lux system. We have developed a computational approach that, for the first time, allows users of Lux assays to infer gene transcription levels from the light output. This approach is based upon a new mathematical model for Lux activity, that includes the actions of LuxAB, LuxEC and Fre, with improved mechanisms for all reactions, as well as synthesis and turn-over of Lux proteins. The model is calibrated with new experimental data for the LuxAB and Fre reactions from Photorhabdus luminescens --- the source of modern Lux reporters --- while literature data has been used for LuxEC. Importantly, the data show clear evidence for previously unreported product inhibition for the LuxAB reaction. Model simulations show that predicted bioluminescent profiles can be very different from changes in gene expression, with transient peaks of light output, very similar to light output seen in some experimental data sets. By incorporating the calibrated model into a Bayesian inference scheme, we can reverse engineer promoter activity from the bioluminescence. We show examples where a decrease in bioluminescence would be better interpreted as a switching off of the promoter, or where an increase in bioluminescence would be better interpreted as a longer period of gene expression. This approach could benefit all users of Lux technology

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    Liver Stiffness Severity is Associated With Increased Cardiovascular Risk in Patients With Type 2 Diabetes

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    Cardiovascular disease (CVD) is the leading cause of death among patients with nonalcoholic fatty liver disease (NAFLD) and is strongly associated with type 2 diabetes mellitus (DM2).(1) Accurately assessing CVD risk in NAFLD patients is critical to improving clinical outcomes.(1) Use of liver stiffness measurements to noninvasively assess for liver fibrosis is broadening, and magnetic resonance elastography (MRE) is the most accurate modality in NAFLD.(2) However, the association between fibrosis severity on MRE and the degree of CVD risk is unknown. The aim of this study was to determine whether MRE-assessed liver fibrosis stage is associated with CVD risk determined by Framingham risk score (FRS) and coronary artery calcium (CAC)

    Acute Ischaemic Stroke and Acute Myocardial Infarction Occurring Together in Domestic Low- Voltage (220-240V) Electrical Injury : A Rare Complication

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    Abstract Background : Myocardial Infarction and Ischaemic stroke are potential outcome after an electric shock though it is seen relatively rarely

    Real-world clinical outcomes of patients with myelofibrosis treated with ruxolitinib: a medical record review

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    Aim: To assess real-world ruxolitinib treatment patterns and outcomes in patients diagnosed with primary or secondary myelofibrosis. Materials & methods: Patient medical records were reviewed in six countries. Results: Eligible patients (n = 469) had a mean age of 63.5 years, and most were male (66.5%) with primary myelofibrosis (78.5%). Median duration of ruxolitinib treatment was 13.1 months; 40% of patients initiated treatment at the recommended dose. The Kaplan-Meier estimate of median survival from ruxolitinib initiation was 44.4 months (95% CI, 38.8-50.2 months). Approximately one quarter (23%) of patients continued ruxolitinib after progression. Conclusion: These results suggest an unmet need for more effective treatments for patients with myelofibrosis who failed ruxolitinib
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