C-Reactive Protein-to-Albumin Ratio as a Prognostic Inflammatory Marker in COVID-19

Objectives As a result of developed generalized inflammation, the main prognostic factor determining morbidity and mortality in coronavirus disease 2019 (COVID-19) patients is acute respiratory distress syndrome. The purpose of our study was to define (1) the laboratory tests that will contribute to the diagnosis and follow-up of COVID-19 patients, (2) the differences between the laboratory-confirmed (LC), unconfirmed (LUC), and control (C) groups, and (3) the variation between groups of acute-phase reactants and biomarkers that can be used as an indicator of disease severity and inflammation. Materials and Methods A total of 102 patients undergoing treatment with COVID-19 interim guidelines were evaluated. Reverse transcriptase-polymerase chain reaction (RT-PCR) test was positive in 56 (LC), classified as mild or severe, and negative in 46 (LUC) patients. In addition, 30 healthy subjects (C) with negative RT-PCR tests were also evaluated.All statistical analyses were performed with the SPSS 22.0 program and the p-values for significant findings were less than 0.05. Parametric/nonparametric distribution was determined by performing the Kolmogorov–Smirnov test for all groups. Student's t-test was used for variables with parametric distribution and the Mann–Whitney U-test for variables with the nonparametric distribution. A cut-off level for biomarkers was determined using the ROC (receiver operator characteristic) curve. Results In the LC group, platelet, platecrit, mean platelet volume, platelet diameter width, white blood cell, lymphocyte, eosinophil, neutrophil, immature granulocyte, immature lymphocyte, immature monocyte, large immune cell, and atypical lymphocyte counts among the complete blood count parameters of mature and immature cell counts showed a significant difference according to the C and LUC groups. C-reactive protein, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and C-reactive protein-to-albumin ratio (CAR) indices were significantly elevated in LC patients and were significantly higher in patients classified as severe compared to mild. When CAR optimal cutoff was determined as 0.475, area under the curve was 0.934, sensitivity was 90.91%, specificity was 86.21%, positive predictive value was 92.59%, and negative predictive value was 83.33%. The diagnostic accuracy for CAR was 89.29%. Conclusion The CAR index with the highest diagnostic value and the highest predictability could be the most useful biomarker in the diagnosis and evaluation of disease severity in COVID-19 patients.

Comparing Calculated LDL with Direct Method: A Retrospective, Real-World Evidence Study on Diagnostic Lab Reports from A Single Center in India

Objective: To compare and validate the calculated LDL values from Friedewald and Anandaraja formulas with directly measured values in the Indian population. Material and Methods: The study was conducted on randomly selected 102 individuals of 16 to 88 years of age during December 2019. The direct LDL values were measured using selective solubilization assay, and Friedewald and Anandaraja formulas were used to calculate LDL for comparison. The correlations between direct and calculated methods were assessed using the linear regression method. Receiver operating characteristic analysis with nonparametric distribution was used to compare the sensitivity and specificity of the three methods. Results: The average LDL of direct method, 107.3 mg/dL, Friedewald formula, 89.7 mg/dL, and Anandaraja was 99.0 mg/dL. The relation between direct and calculated values assessed by linear regression showed 97% and 87% of correlation with Friedewald and Anandaraja, respectively. The ROC analysis inferred that direct (AUC 0.74; 95% CI 0.64-0.83) and Friedewald (AUC 0.71; 95% CI 0.61-0.81) methods had shown about 70% efficiency in predicting true positive and true negative dyslipidemia cases. In our dataset, the Anandaraja formula could not well differentiate positives from negative cases of dyslipidemia with merely 60% AUC. Conclusion: The underpredicted values from the Friedewald formula were associated with deranged cholesterol and HDL values, not triglycerides. Anandaraja formula overpredicted by 10 to 30 mg/dL when triglycerides were <150 mg/dL and underpredicted by 10-43 mg/dL while non-HDL was >140 mg/dL.

Modeling Electricity Price and Quantity Uncertainty: An Application for Hedging with Forward Contracts

Energy transactions in liberalized markets are subject to price and quantity uncertainty. This paper considers the spot price and energy generation to follow a bivariate semi-nonparametric distribution defined in terms of the Gram–Charlier expansion. This distribution allows us to jointly model not only mean, variance, and correlation but also skewness, kurtosis, and higher-order moments. Based on this model, we propose a static hedging strategy for electricity generators that participate in a competitive market where hedging is carried out through forward contracts that include a risk premium in their valuation. For this purpose, we use Monte Carlo simulation and consider information from the Colombian electricity market as the case study. The results show that the volume of energy to be sold under long-term contracts depends on each electricity generator and the risk assessment made by the market in the forward risk premium. The conditions of skewness, kurtosis, and correlation, as well as the type of the employed risk indicator, affect the hedging strategy that each electricity generator should implement. A positive correlation between the spot price and energy production tends to increase the hedge ratio; meanwhile, negative correlation tends to reduce it. The increase of forward risk premium, on the other hand, reduces the hedge ratio.

Robust Nonparametric Distribution Transfer with Exposure Correction for Image Neural Style Transfer

Image neural style transfer is a process of utilizing convolutional neural networks to render a content image based on a style image. The algorithm can compute a stylized image with original content from the given content image but a new style from the given style image. Style transfer has become a hot topic both in academic literature and industrial applications. The stylized results of current existing models are not ideal because of the color difference between two input images and the inconspicuous details of content image. To solve the problems, we propose two style transfer models based on robust nonparametric distribution transfer. The first model converts the color probability density function of the content image into that of the style image before style transfer. When the color dynamic range of the content image is smaller than that of style image, this model renders more reasonable spatial structure than the existing models. Then, an adaptive detail-enhanced exposure correction algorithm is proposed for underexposed images. Based this, the second model is proposed for the style transfer of underexposed content images. It can further improve the stylized results of underexposed images. Compared with popular methods, the proposed methods achieve the satisfactory qualitative and quantitative results.

Reference Intervals for and the Effects of Sample Handling and Sex on Rotational Thromboelastometry in Healthy Adult Pigs

Accurate assessment of coagulation in porcine studies is essential. We sought to establish normal values for porcine rotational thromboelastometry (ROTEM) according to the American Society for Veterinary Clinical Pathology guidelines and to assess the effects of various preanalytical parameters on those measurements. Healthy Yorkshire-cross pigs (n = 81; 46 males and 35 females) were anesthetized. By using a 18-gauge needle attached to a vacuum phlebotomy tube, blood was acquired from the cranial vena cava. Tubes were filled in the following order: evacuation clot tube, EDTA tube, heparin tube, and 2 citrate tubes. The citrate tubes were randomly assigned to 30 min with or without constant agitation on a rocker. The following parameters were reported according to the manufacturer's recommendations: clotting time, clot formation time, α, (tangent to the clot formation curve when the clot firmness is 20 mm), clot firmness after 10 and 20 min, maximal clot firmness, maximum lysis, and lysis indexes at 30 and 45 min. Reference intervals were reported as mean ± 2 SD (parametric distribution) or 2.5th and 97.5th percentile of the population's results (nonparametric distribution). The effects of sex, sampling order, and agitation on ROTEM results were analyzed through linear regression. Neither sex nor sample agitation influenced any of the ROTEM parameters. Combined reference intervals were established for each ROTEM parameter by pooling data from the nonagitated tubes for both male and female pigs. This study is the first to establish ROTEM reference intervals from a large number of male and female adult Yorkshire-cross pigs and to provide a detailed description of preanalytical sample processing.

Transurethral endoscopic approach for large bladder diverticula: Evaluation of a large series

Objective: To present the results of the largest series of patients with bladder diverticula > 4 cm managed with an endoscopic approach and give tips about the execution of the procedure. Materials and methods: Data of male patients undergone the endoscopic approach for an acquired bladder diverticula > 4 cm from December 2004 to August 2018 were prospectively collected and retrospectively analyzed. The description of the monopolar and bipolar techniques are provided. The success of the procedure was defined as the reduction of the diverticula for more of the 80% of its initial diameter documented at the 3- months follow-up imaging. Continuous variables with nonparametric distribution were compared using the Mann-Whitney test, while frequencies of categorical variables were compared between groups by Fisher’s exact test with significance level set at 0.05. Results: Thirty-nine patients with a mean (+/- SD) age at surgery of 69.4 ± 8.8 years were enrolled, for an equal number of diverticula managed. The mean diverticular size was 75.1 ± 24.5 millimeters. The mean operative time was 65 ± 21.9 minutes including the prostate surgery. Twelve patients (30.8%) were managed with bipolar energy, the others with monopolar. The success of the procedure was achieved in 30 patients (76.9% - 7 bipolar and 23 monopolar - p = 0.66). Conclusions: The endoscopic approach might be considered as a useful option for patients with a large bladder diverticulum who are at risk for major or laparoscopic procedure.