We seek to describe the medical history and clinical findings of patients attending the emergency department (ED) with suspected coronavirus disease 2019 and estimate the diagnostic accuracy of patients' characteristics for predicting COVID-19. Methods:We prospectively enrolled all patients tested for severe acute respiratory syndrome coronavirus 2 by reversetranscriptase polymerase chain reaction in our ED from March 9, 2020, to April 4, 2020. We abstracted medical history, physical examination findings, and the clinical probability of COVID-19 (low, moderate, and high) rated by emergency physicians, depending on their clinical judgment. We assessed diagnostic accuracy of these characteristics for COVID-19 by calculating positive and negative likelihood ratios.Results: We included 391 patients, of whom 225 had positive test results for severe acute respiratory syndrome coronavirus 2. Reverse-transcriptase polymerase chain reaction result was more likely to be negative when the emergency physician thought that clinical probability was low, and more likely to be positive when he or she thought that it was high. Patient-reported anosmia and the presence of bilateral B lines on lung ultrasonography had the highest positive likelihood ratio for the diagnosis of COVID-19 (7.58, 95% confidence interval [CI] 2.36 to 24.36; and 7.09, 95% CI 2.77 to 18.12, respectively). The absence of a high clinical probability determined by the emergency physician and the absence of bilateral B lines on lung ultrasonography had the lowest negative likelihood ratio for the diagnosis of COVID-19 (0.33, 95% CI 0.25 to 0.43; and 0.26, 95% CI 0.15 to 0.45, respectively). Conclusion:Anosmia, emergency physician estimate of high clinical probability, and bilateral B lines on lung ultrasonography increased the likelihood of identifying COVID-19 in patients presenting to the ED.

Multidrug resistance (MDR) in tumour cells is often caused by the overexpression of the plasma drug transporter P-glycoprotein (P-gp). This protein is an active efflux pump for chemotherapeutic drugs, natural products and hydrophobic peptides. Despite the advances of recent years, we still have an unclear view of the molecular mechanism by which P-gp transports such a wide diversity of compounds across the membrane. Measurement of the kinetic characteristics of substrate transport is a powerful approach to enhancing our understanding of their function and mechanism. The aim of the present study was to further characterize the transport of several rhodamine analogues, either positively charged or zwitterionic. We took advantage of the intrinsic fluorescence of rhodamines and performed a flow-cytometric analysis of dye accumulation in the wild-type drug sensitive K562 that do not express P-gp and its MDR subline that display high levels of MDR. The measurements were made in real time using intact cells. The kinetic parameter, k a ¼ V M /k m , which is a measure of the efficiency of the P-gp-mediated efflux of a substrate was similar for almost all the rhodamine analogues tested. In addition these values were compared with those determined previously for the P-gp-mediated efflux of anthracycline. Our conclusion is that the compounds of these two classes of molecules, anthracyclines and rhodamines, are substrates of P-gp and that their pumping rates at limiting low substrate concentration are similar. The findings presented here are the first to show quantitative information about the kinetic parameters for P-gp-mediated efflux of rhodamine analogues in intact cells.Keywords: P-glycoprotein; multidrug resistance; membrane transport; rhodamine; efflux. Since 1940, a broad variety of antibiotics active against many infectious organisms were discovered or developed. The widespread, and sometimes uncontrolled, use of these drugs has led to the emergence of defence mechanisms that, at present, are the major drawback of the drug-based treatment of infectious diseases and cancers. Such resistance is not restricted to the drugs (or analogues) used in the treatment but also involves several structurally and functionally unrelated compounds. This phenomenon, which has been termed multidrug resistance (MDR), can be caused by various mechanisms. However, over expression of the P-glycoprotein multidrug transporter (P-gp) in the plasma membrane is believed to be a major cause of resistance to multiple chemotherapeutic drugs [1][2][3][4]. P-gp is an unusual ABC protein in that it appears to be highly promiscuous: hundreds of compounds have been identified as substrates. The spectrum of MDR compounds includes a large number of anticancer drugs (e.g. anthracyclines, vinca alkaloids, taxanes) as well as steroids, fluorescent dyes, rhodamines, and the c-emitting radio pharmaceutical 99m Tc-MIBI. P-gp can transport neutral and positively charged molecules but not negatively charged ones. Despite the advances of recent years, we still h...

The multidrug resistance protein (MRP) has been shown to mediate ATP-dependent efflux of anticancer agents of diverse structure, such as daunorubicin (DNR), vincristine and etoposide. Thus, this protein does confer a multidrug resistant phenotype to cancer cells, similar to P-glycoprotein (Pgp). The substrate specificity of both transporter proteins is partly overlapping but is otherwise very distinct; because MRP is a multiple organic anion transporter, it transports certain glutathione conjugates and may be partly dependent on intracellular glutathione levels for the transport of anthracyclines. We have studied the transport kinetics of a series of anthracyclines in MRP and Pgp that overexpress tumor cell lines to obtain information on the substrate specificity of these proteins. The anthracyclines have modifications in the sugar moiety. The mean active efflux coefficient Ka, used to characterize the efficiency of the active efflux, was very similar for DNR and one of its 4'-deoxy-derivatives (eso-DNR) for MRP and Pgp [10-20 x 10(-10)/sec/(cells/ml)]. The permanently neutral derivatives 3'-deamino-3'-hydroxy-doxorubicin (OH-DOX) and 3'-deamino-3'-hydroxy-daunorubicin (OH-DNR) were effluxed by both proteins but had a lower Ka [2 x 10(-10) and 6 x 10(-10)/sec/(cells/ml) (OH-DOX)] and 2 x 10(-10) and 5 x 10(-10)/sec/(cells/ml) (OH-DNR)] for MRP and Pgp. Two anthracyclines, the doxorubicin derivative pirarubicin and 2'-bromo-4'-epi-DNR seemed to have a slightly higher Ka value for Pgp than for MRP. The apparent Michaelis-Menten constants (K(m)) and maximal efflux rates (VM) for the active transport were within a narrow range for both transporters, except for OH-DOX and OH-DNR, which had a lower VM in the case of MRP-mediated transport, suggesting a role of the amino group in the interaction with glutathione. Determination of the Hill coefficient (nH) of the MRP-mediated efflux gave most values close to 2, which suggests cooperativity of the transport of anthracyclines as reported before for Pgp. In conclusion, the transport kinetics of anthracyclines by MRP and Pgp are very similar.

Introduction The rate of weaning of vasopressors drugs is usually an empirical choice made by the treating in critically ill patients. We applied fuzzy logic principles to modify intravenous norepinephrine (noradrenaline) infusion rates during norepinephrine infusion in septic patients in order to reduce the duration of shock.