24 research outputs found

    Evaluation of Few-View Reconstruction Parameters for Illicit Substance Detection using Fast-Neutron Transmission Spectroscopy

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    We have evaluated the performance of an illicit substance detection system that performs image reconstruction using the Maximum Likelihood algebraic reconstruction algorithm, a few number of projections, and relatively coarse projection and pixel resolution. This evaluation was done using receiver operator curves and simulated data from the fast-neutron transmission spectroscopy system operated in a mode to detect explosives in luggage. The results show that increasing the number of projection angles is more important than increasing the projection resolution, the reconstructed pixel resolution, or the number of iterations in the Maximum Likelihood algorithm. A 100% detection efficiency with essentially no false positives is possible for a square block of RDX explosive, a projection resolution of 2 cm, a reconstructed pixel size of 2x2 cm, and five projection angles. For rectangular shaped explosives more angles are required to obtain the same system performance

    Plato's Cave Algorithm: Inferring Functional Signaling Networks from Early Gene Expression Shadows

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    Improving the ability to reverse engineer biochemical networks is a major goal of systems biology. Lesions in signaling networks lead to alterations in gene expression, which in principle should allow network reconstruction. However, the information about the activity levels of signaling proteins conveyed in overall gene expression is limited by the complexity of gene expression dynamics and of regulatory network topology. Two observations provide the basis for overcoming this limitation: a. genes induced without de-novo protein synthesis (early genes) show a linear accumulation of product in the first hour after the change in the cell's state; b. The signaling components in the network largely function in the linear range of their stimulus-response curves. Therefore, unlike most genes or most time points, expression profiles of early genes at an early time point provide direct biochemical assays that represent the activity levels of upstream signaling components. Such expression data provide the basis for an efficient algorithm (Plato's Cave algorithm; PLACA) to reverse engineer functional signaling networks. Unlike conventional reverse engineering algorithms that use steady state values, PLACA uses stimulated early gene expression measurements associated with systematic perturbations of signaling components, without measuring the signaling components themselves. Besides the reverse engineered network, PLACA also identifies the genes detecting the functional interaction, thereby facilitating validation of the predicted functional network. Using simulated datasets, the algorithm is shown to be robust to experimental noise. Using experimental data obtained from gonadotropes, PLACA reverse engineered the interaction network of six perturbed signaling components. The network recapitulated many known interactions and identified novel functional interactions that were validated by further experiment. PLACA uses the results of experiments that are feasible for any signaling network to predict the functional topology of the network and to identify novel relationships

    Anesthesia and circulating tumor cells in primary breast cancer patients: a randomized controlled trial

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    BACKGROUND: The effect of anesthetic drugs on cancer outcomes remains unclear. This trial aimed to assess postoperative circulating tumor cell counts-an independent prognostic factor for breast cancer-to determine how anesthesia may indirectly affect prognosis. It was hypothesized that patients receiving sevoflurane would have higher postoperative tumor cell counts. METHODS: The parallel, randomized controlled trial was conducted in two centers in Switzerland. Patients aged 18 to 85 yr without metastases and scheduled for primary breast cancer surgery were eligible. The patients were randomly assigned to either sevoflurane or propofol anesthesia. The patients and outcome assessors were blinded. The primary outcome was circulating tumor cell counts over time, assessed at three time points postoperatively (0, 48, and 72 h) by the CellSearch assay. Secondary outcomes included maximal circulating tumor cells value, positivity (cutoff: at least 1 and at least 5 tumor cells/7.5 ml blood), and the association between natural killer cell activity and tumor cell counts. This trial was registered with ClinicalTrials.gov (NCT02005770). RESULTS: Between March 2014 and April 2018, 210 participants were enrolled, assigned to sevoflurane (n = 107) or propofol (n = 103) anesthesia, and eventually included in the analysis. Anesthesia type did not affect circulating tumor cell counts over time (median circulating tumor cell count [interquartile range]; for propofol: 1 [0 to 4] at 0 h, 1 [0 to 2] at 48 h, and 0 [0 to 1] at 72 h; and for sevoflurane: 1 [0 to 4] at 0 h, 0 [0 to 2] at 48 h, and 1 [0 to 2] at 72 h; rate ratio, 1.27 [95% CI, 0.95 to 1.71]; P = 0.103) or positivity. In one secondary analysis, administrating sevoflurane led to a significant increase in maximal tumor cell counts postoperatively. There was no association between natural killer cell activity and circulating tumor cell counts. CONCLUSIONS: In this randomized controlled trial investigating the effect of anesthesia on an independent prognostic factor for breast cancer, there was no difference between sevoflurane and propofol with respect to circulating tumor cell counts over time

    A Delphi-Based Consensus Statement on the Management of Anticoagulated Patients With Botulinum Toxin for Limb Spasticity.

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    Objective To create a consensus statement on the considerations for treatment of anticoagulated patients with botulinum toxin A (BoNTA) intramuscular injections for limb spasticity. Design We used the Delphi method. Setting A multiquestion electronic survey. Participants Canadian physicians (N=39) who use BoNTA injections for spasticity management in their practice. Interventions After the survey was sent, there were e-mail discussions to facilitate an understanding of the issues underlying the responses. Consensus for each question was reached when agreement level was ≥75%. Main Outcome Measures Not applicable. Results When injecting BoNTA in anticoagulated patients: (1) BoNTA injections should not be withheld regardless of muscles injected; (2) a 25G or smaller size needle should be used when injecting into the deep leg compartment muscles; (3) international normalized ratio (INR) level should be ≤3.5 when injecting the deep leg compartment muscles; (4) if there are clinical concerns such as history of a fluctuating INR, recent bleeding, excessive or new bruising, then an INR value on the day of injection with point-of-care testing or within the preceding 2-3 days should be taken into consideration when injecting deep compartment muscles; (5) the concern regarding bleeding when using direct oral anticoagulants (DOACs) should be the same as with warfarin (when INR is in the therapeutic range); (6) the dose and scheduling of DOACs should not be altered for the purpose of minimizing the risk of bleeding prior to BoNTA injections. Conclusions These consensus statements provide a framework for physicians to consider when injecting BoNTA for spasticity in anticoagulated patients. These consensus statements are not strict guidelines or decision-making steps, but rather an effort to generate common understanding in the absence of evidence in the literature
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