Thymomas: a review.

Thymomas are neoplasma of thymic epithelial cells. They may be benign or malignant and may associate with locai ìnvasiveness and paraneoplastic diseases. Myasthenia gravis is often associated with thymomas, bui this is not thè rule. Several classifications have been proposed: some of them follow thè histopathological findings (Rosai and Levine, Snover, Marino and Muller- Hermelink classification), other emphasizes thè clinic-pathological stage (Masaoka, Verley and Hollmann stadiation). One third of thymomas is asymptomatic. Diagnosis is made often by plain X-ray and confirmed by Computed Tomography or fine needle biopsy. Surgery is effective in 100% of noninvasive cases and in 58% of invasive ones. Radio and chemotherapy are recommended only in advanced or inoperable stages

Quality of life after tailored combined surgery for stage I non-small-cell lung cancer and severe emphysema

Background. We analyzed the early and long-term quality of life changes occurring in 16 patients undergoing tailored combined surgery for stage I non-small-cell lung cancer (NSCLC) and severe emphysema. Methods. Mean age was 65 +/- 5 years. All patients had severe emphysema with severely impaired respiratory function and quality of life. Tumor resection was performed with sole lung volume reduction (LVR) in 5 patients, separate wedge resection in 3 patients, segmentectomy in 2 patients, and lobectomy in 6 patients. A bilateral LVR was performed in 5 patients. Quality of life was assessed at baseline and every 6 months postoperatively by the Short-form 36 (SF-36) item questionnaire. Results. Mean follow-up was 44 +/- 21 months. All tumors were pathologic stage I. There was no hospital mortality nor major morbidity. Significant improvements occurred for up to 36 months in the general health (p = 0.02) domain and for up to 24 months in physical functioning (p = 0.02), role physical (p = 0.005), and general health (P = 0.01) SF-36 domains. Associated improvements regarded dyspnea index (-1.3 +/- 0.6) forced expiratory volume in one second (+0.28 +/- 0.2L), residual volume (-1.18 +/- 0.5L) and 6-minute-walking test distance (+86 +/- 67 m). Actuarial 5-year survival was similar to that of patients with no cancer undergoing LVRS during the same period (68% vs 82%, p = not significant). Conclusions. Our study suggests that selected patients with stage I NSCLC and severe emphysema may significantly benefit from tailored combined surgery in terms of long-term quality of life and survival. (Ann Thorac Surg 2003;76:1821-7

Estimate risk difference and number needed to treat in survival analysis

The hazard ratio (HR) is a measure of instantaneous relative risk of an increase in one unit of the covariate of interest, which is widely reported in clinical researches involving time-to-event data. However, the measure fails to capture absolute risk reduction. Other measures such as number needed to treat (NNT) and risk difference (RD) provide another perspective on the effectiveness of an intervention, and can facilitate clinical decision making. The article aims to provide a step-by-step tutorial on how to compute RD and NNT in survival analysis with R. For simplicity, only one measure (RD or NNT) needs to be illustrated, because the other measure is a reverse of the illustrated one (NNT=1/RD). An artificial dataset is composed by using the survsim package. RD and NNT are estimated with Austin method after fitting a Cox-proportional hazard regression model. The confidence intervals can be estimated using bootstrap method. Alternatively, if the standard errors (SEs) of the survival probabilities of the treated and control group are given, confidence intervals can be estimated using algebraic calculations. The pseudo-value model provides another method to estimate RD and NNT. Details of R code and its output are shown and explained in the main text

Želučano-crijevni nametnici i prvi nalaz Giardia spp. u slobodno-živućoj populaciji europskoga smeđeg medvjeda (Ursus arctos) u Hrvatskoj.

Ninety-four European brown bear (Ursus arctos) faecal samples, collected in three counties of Croatia, were examined for the presence of gastrointestinal parasites. Five genera were identified, including the nematodes Baylisascaris transfuga and Syngamus sp., and the protozoan enteropathogens Cryptosporidium sp., Eimeria sp., and Giardia sp. Ancylostomatid eggs were also recovered. Cestodes, trematodes and acanthocephalan eggs were absent from all samples. This is the first parasite survey of brown bears in Croatia in thirty years and the first report of Giardia in this species from the region.Devedeset i četiri uzorka izmeta europskoga smeđeg medvjeda (Ursus arctos), sakupljena u tri županije u Hrvatskoj, pregledana su na prisutnost želučano-crijevnih nametnika. Utvrđeno je ukupno 5 rodova, uključujući nematode Baylisascaris transfuga i Syngamus sp., te enteropatogene protozoe Cryptosporidium sp., Eimeria sp. i Giardia sp. Utvrđena su i jaja ankilostomatida dok jaja cestoda, trematoda i akantocefala nisu pronađena. Ovo je prvo parazitološko istraživanje smeđeg medvjeda u Hrvatskoj u posljednjih 30 godina i prvi nalaz Giardia spp. u ove vrste s ovog područja

Incidence of pneumomediastinum in COVID-19: A single-center comparison between 1st and 2nd wave

In this study, we compared the incidence of pneumomediastinum in coronavirus disease (COVID-19) patients during the ascending phases of the 1st and 2nd epidemic waves. Crude incidence was higher during the 2nd wave at a quasi-significant level (0.68/1000 vs. 2.05/1000 patient-days, p = 0.05). When restricting the analysis to patients who developed pneumomediastinum during noninvasive ventilation, the difference became clearly significant (0.17/1000 vs 1.36/1000 patient-days, p = 0.039). At logistic regression, predisposing factors (p = 0.031), and COVID-19 radiological severity (p = 0.019) were independently associated with pneumomediastinum. Mortality in patients with pneumomediastinum was 87.5%. However, pneumomediastinum seemed to be related to a generally worse disease presentation in hospitalized patients during the 2nd wave, rather than to a separate pattern of disease. (C) 2021 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved

Statistical analysis of high-dimensional biomedical data: a gentle introduction to analytical goals, common approaches and challenges

International audienceBackground: In high-dimensional data (HDD) settings, the number of variables associated with each observation is very large. Prominent examples of HDD in biomedical research include omics data with a large number of variables such as many measurements across the genome, proteome, or metabolome, as well as electronic health records data that have large numbers of variables recorded for each patient. The statistical analysis of such data requires knowledge and experience, sometimes of complex methods adapted to the respective research questions. Methods: Advances in statistical methodology and machine learning methods offer new opportunities for innovative analyses of HDD, but at the same time require a deeper understanding of some fundamental statistical concepts. Topic group TG9 “High-dimensional data” of the STRATOS (STRengthening Analytical Thinking for Observational Studies) initiative provides guidance for the analysis of observational studies, addressing particular statistical challenges and opportunities for the analysis of studies involving HDD. In this overview, we discuss key aspects of HDD analysis to provide a gentle introduction for non-statisticians and for classically trained statisticians with little experience specific to HDD. Results: The paper is organized with respect to subtopics that are most relevant for the analysis of HDD, in particular initial data analysis, exploratory data analysis, multiple testing, and prediction. For each subtopic, main analytical goals in HDD settings are outlined. For each of these goals, basic explanations for some commonly used analysis methods are provided. Situations are identified where traditional statistical methods cannot, or should not, be used in the HDD setting, or where adequate analytic tools are still lacking. Many key references are provided. Conclusions: This review aims to provide a solid statistical foundation for researchers, including statisticians and non-statisticians, who are new to research with HDD or simply want to better evaluate and understand the results of HDD analyses

Efficient melt stabilization of polyethylene with quercetin, a flavonoid type natural antioxidant

The potential use of quercetin, a flavonoid type natural antioxidant, as a stabilizer in polyethylene was explored in this work. Its efficiency was compared to that of Irganox 1010, a hindered phenolic antioxidant used routinely in industrial practice, both in the presence and the absence of a phosphorous secondary stabilizer. The study was carried out with a Phillips type polyethylene and the efficiency of the additive packages was checked by various methods on samples produced by multiple extrusions. Quercetin content changed from 0 to 1000 ppm in 10 steps. The results showed that quercetin is a very effi-cient antioxidant. It prevents the formation of long chain branches already at a concentra-tion as small as 50 ppm and its dosage at 250 ppm renders the polymer sufficient long term residual stability. The efficiency of quercetin is considerably better than that of Irganox 1010, the hindered phenolic antioxidant used as reference stabilizer. The difference in efficiency might be explained with the dissimilar number of active –OH groups on the two molecules, but the stabilization mechanism of quercetin may be also different from that of I1010. Quercetin interacts with the phosphonite secondary stabilizer used, which improves dispersion and increases efficiency. Besides its advantages, quercetin has also some drawbacks (very high melting temperature, poor solubility in polyethylene and strong yellow color), which must be overcome before the substance can be used in practice

Effects of seagrasses and algae of the Caulerpa family on hydrodynamics and particle-trapping rates

The widespread decline of seagrass beds within the Mediterranean often results in the replacement of seagrasses by opportunistic green algae of the Caulerpa family. Because Caulerpa beds have a different height, stiffness and density compared to seagrasses, these changes in habitat type modify the interaction of the seafloor with hydrodynamics, influencing key processes such as sediment resuspension and particle trapping. Here, we compare the effects on hydrodynamics and particle trapping of Caulerpa taxifolia, C. racemosa, and C. prolifera with the Mediterranean seagrasses Cymodocea nodosa and Posidonia oceanica. All macrophyte canopies reduced near-bed volumetric flow rates compared to bare sediment, vertical profiles of turbulent kinetic energy revealed peak values around the top of the canopies, and maximum values of Reynolds stress increased by a factor of between 1.4 (C. nodosa) and 324.1 (P. oceanica) when vegetation was present. All canopies enhanced particle retention rates compared to bare sediment. The experimental C. prolifera canopy was the most effective at particle retention (m2 habitat); however, C. racemosa had the largest particle retention capacity per structure surface area. Hence, in terms of enhancing particle trapping and reducing hydrodynamic forces at the sediment surface, Caulerpa beds provided a similar or enhanced function compared to P.oceanica and C. nodosa. However, strong seasonality in the leaf area index of C. racemosa and C. taxifolia within the Mediterranean, combined with a weak rhizome structure, suggests that sediments maybe unprotected during winter storms, when most erosion occurs. Hence, replacement of seagrass beds with Caulerpa is likely to have a major influence on annual sediment dynamics at ecosystem scales.This research was funded by the European Network of Excellence ‘‘Marine Biodiversity and Ecosystem Function’’ (MarBEF); FP6, EC contract no. 505446 and a grant from the Fundacio ´n BBVA. EPM was supported by a European Union Marie Curie host fellowship for transfer of knowledge, MTKD-CT-2004-509254, the Spanish national project EVAMARIA (CTM2005-00395/MAR) and the regional government of Andalusia project FUNDIV(P07-RNM-2516)