328 research outputs found
Die GesetzmÀssigkeit von Wohlstand
Der englische Ăkonom David Ricardo gilt als Vater der modernen Handelstheori
Ganciclovir/Valganciclovir Prophylaxis Decreases Cytomegalovirus-Related Events and Bronchiolitis Obliterans Syndrome after Lung Transplantation
Background. Until recently, cytomegalovirus (CMV) infection represented a major threat to lung transplant recipients. Preliminary studies have shown that antiviral prophylaxis might improve the outcome for these patients. Methods. We extended our initial pilot trial of prolonged prophylaxis with either oral ganciclovir (1 g 3 times per day) or valganciclovir (450 mg twice per day). The trial included 96 patients who were at risk for CMV-related events. Results. CMV prophylaxis resulted in a significant decrease in CMV-related events (i.e., active infection and disease), from 75% in a control group and for 274 cases from the literature who did not receive prophylaxis to a cumulative incidence of 27% (P<.001). Only 11% of the prophylaxis recipients experienced CMV disease (P<.001). Moreover, at 5 years, there was a significant decrease in the rate of bronchiolitis obliterans syndrome, from 60% to 43% (P=.002), and an improved rate of survival, from 47% to 73% (P=.036), irrespective of the immunosuppressive regimen received. CMV strains with UL97 mutations were recovered from 7 of 12 analyzed cases, but the presence of this mutation had no impact on the severity of CMV disease. Conclusions. A regimen of prolonged ganciclovir or valganciclovir prophylaxis decreased the rate of active CMV infection and disease, reduced the incidence of bronchiolitis obliterans syndrome, and improved the survival rate. Drug-resistant CMV strains may occur, but such strains appeared to have no impact on the outcome of CMV-related event
Towards a population synthesis of discs and planets. II. Confronting disc models and observations at the population level
Aims. We want to find the distribution of initial conditions that best
reproduces disc observations at the population level. Methods. We first ran a
parameter study using a 1D model that includes the viscous evolution of a gas
disc, dust, and pebbles, coupled with an emission model to compute the
millimetre flux observable with ALMA. This was used to train a machine learning
surrogate model that can compute the relevant quantity for comparison with
observations in seconds. This surrogate model was used to perform parameter
studies and synthetic disc populations. Results. Performing a parameter study,
we find that internal photoevaporation leads to a lower dependency of disc
lifetime on stellar mass than external photoevaporation. This dependence should
be investigated in the future. Performing population synthesis, we find that
under the combined losses of internal and external photoevaporation, discs are
too short lived. Conclusions. To match observational constraints, future models
of disc evolution need to include one or a combination of the following
processes: infall of material to replenish the discs, shielding of the disc
from internal photoevaporation due to magnetically driven disc winds, and
extinction of external high-energy radiation. Nevertheless, disc properties in
low-external-photoevaporation regions can be reproduced by having more massive
and compact discs. Here, the optimum values of the viscosity parameter
lie between and and with internal photoevaporation
being the main mode of disc dispersal.Comment: Accepted for publication in A&A; minor changes in the reference lis
Proposal for a new local recurrence score in patients with recurrent malignant pleural mesothelioma
BACKGROUND
Malignant pleural mesothelioma (MPM) is associated with high rates of local recurrence (LR) up to 75%. Second line treatment should be applied tailored to relapse pattern. We aimed to establish a new score for LR pattern with prognostic impact in this observational study of retrospective nature.
METHODS
MPM patients with LR after surgery, verified by serial imaging during follow-up visits or biopsy were included in a retrospective analysis using a new local recurrence score (LRS). We divided the thoracic cavity into six sections and calculated the LRS according to the tumor burden. We assessed the impact on survival after recurrence using cox regression model.
RESULTS
From 2001 until 2017, 128 consecutive MPM patients with LR who underwent macroscopic complete resection (MCR) by extrapleural pneumonectomy (EPP, n=61) or by (extended) pleurectomy/decortication [(E)PD, n=67], were included in the present analysis; 104 patients received second line therapy. Patients with chest wall (CW) recurrence had the shortest survival after recurrence (9 vs. 16 months, P=0.05) as well as patients with affected lymph nodes (LN) (9 vs. 17 months, P=0.02). In subgroup analysis, the (E)PD group had a significantly higher LRS (Pâ€0.001) despite a longer survival time after recurrence of 12.4 months (IQR, 6.45-20.32) compared to 9.3 months (IQR, 2.93-17.40, EPP group) (P=0.04). Patients with LRS â€4 had a longer survival undergoing radiotherapy or local surgery for second line treatment whereas patients with LRS >4 only if they underwent chemotherapy.
CONCLUSIONS
LRS might be a useful prognostic tool in MPM patients with LR after multimodality therapy to guide second line treatment allocation
Effect of a short period of warm ischemia after cold preservation on reperfusion injury in lung allotransplantation
Objective: A short period of warm ischemia during lung allograft implantation is inevitable. We studied the effect of 2 h of warm ischemia before implantation after 18 h of cold preservation on reperfusion edema and pulmonary hemodynamics in a large animal model. Methods: Left lung transplantation was performed in ten weight-matched pigs (25-31 kg). Donor lungs were flushed with 1.5 l cold (1°C) LPD solution and preserved for 20 h. In Group I (n=5) the grafts were preserved for 20 h at 1°C and topically cooled with ice slush during implantation until reperfusion. In Group II (n=5) lungs were stored at 1°C for 18 h followed by 2 h preservation at room temperature (20°C). Topical cooling was not used during implantation. At 1 h after reperfusion the recipient contralateral right pulmonary artery and bronchus were ligated to assess graft function only. Extravascular lung water index (EVLWI), intrathoracic blood volume (ITBV), mean pulmonary artery pressure (PAP) and cardiac output (CO) were assessed during a 4 h observation period. Quantitative myeloperoxidase (MPO) activity and thiobarbituric acid-reactive substance (TBARS) levels as an indicator for lipid peroxidation were determined in allograft tissue samples taken 5 h after reperfusion. Results: In Group II a tendency to improved pulmonary vascular resistance and cardiac output was noted. Surprisingly, lung edema, assessed by EVLWI, did not increase in animals with warm ischemia. Even a tendency to a reduced EVLWI was noted. However, differences between groups did not reach statistical significance. Gas exchange did not differ statistically significant between groups. Conclusion: Our results indicate that a short period of warm ischemia before reperfusion does not lead to increased pulmonary edema. In animals with a short period of warm ischemia before reperfusion, even a tendency to reduced posttransplant lung reperfusion injury was noted. In this model, topical graft cooling during lung implantation did not improve posttransplant graft functio
Implementing CT tumor volume and CT pleural thickness into future staging systems for malignant pleural mesothelioma
OBJECTIVES
Tumor thickness and tumor volume measured by computed tomography (CT) were suggested as valuable prognosticator for patients' survival diagnosed with malignant pleural mesothelioma (MPM). The purpose was to assess the accuracy of CT scan based preoperatively measured tumor volume and thickness compared to actual tumor weight of resected MPM specimen and pathologically assessed tumor thickness, as well as an analysis of their impact on overall survival (OS).
METHODS
Between 09/2013-08/2018, 74 patients were treated with induction chemotherapy followed by (extended) pleurectomy/decortication ((E)PD). In 53 patients, correlations were made between CT-measured volume and -tumor thickness (cTV and cTT) and actual tumor weight (pTW) based on the available values. Further cTV and pT/IMIG stage were correlated using Pearson correlation. Overall survival (OS) was calculated with Kaplan Meier analysis and tested with log rank test. For correlation with OS Kaplan-Meier curves were made and log rank test was performed for all measurements dichotomized at the median.
RESULTS
Median pathological tumor volume (pTV) and pTW were 530âml [130âml - 1000âml] and 485âmg [95âg - 982âg] respectively. Median (IQR) cTV was 77.2âml (35.0-238.0), median cTT was 9.0âmm (6.2-13.7). Significant association was found between cTV and pTV (Râ=â0.47, pâ<â0.001) and between cTT and IMIG stage (pâ=â0,001) at univariate analysis. Multivariate regression analysis revealed, that only cTV correlates with pTV. Median follow-up time was 36.3âmonths with 30 patients dead at the time of the analysis. Median OS was 23.7âmonths. 1-year and 3-year survival were 90 and 26% respectively and only the cTV remained statistically associated with OS.
CONCLUSION
Preoperatively assessed CT tumor volume and actual tumor volume showed a significant correlation. CT tumor volume may predict pathological tumor volume as a reflection of tumor burden, which supports the integration of CT tumor volume into future staging systems
An evaluation of the metabolic syndrome in a large multi-ethnic study: the Family Blood Pressure Program
BACKGROUND: The Family Blood Pressure Program is an ongoing, NHLBI-sponsored, multi-center program to study the genetic determinants of high blood pressure. The goal of this particular study was to study patterns of metabolic syndrome (MetS) in four ethnic groups: African Americans, Caucasians, Hispanics, and Asians. METHODS: A major part of participants in three networks GENOA, HyperGEN and SAPPHIRe were recruited mainly through hypertensive probands. MetS was defined as a categorical trait following the National Cholesterol Education Program definition (c-MetS). MetS was also characterized quantitatively through multivariate factor analyses (FA) of 10 risk variables (q-MetS). Logistic regression and frequency tables were used for studying associations among traits. RESULTS: Using the NCEP definition, the Hispanic sample, which by design was enriched for type 2 diabetes (T2D), had a very high prevalence of MetS (73%). In contrast, its prevalence in Chinese was the lowest (17%). In African Americans and Hispanics, c-MetS was more prevalent in women than in men. Association of c-MetS with type 2 diabetes (T2D) was prominent in the Hispanics and African Americans, less pronounced in the Whites and Japanese, (although still significant), and weakest in the Chinese sample. Using FA without rotation, we found that the main factor loaded obesity (OBS) and blood pressure (BP) in African Americans; OBS and insulin (INS) in Hispanics, in Japanese, and in Whites; and OBS alone in Chinese. In Hispanics, Whites, and Japanese, BP loaded as a separate factor. Lipids in combination with INS also loaded in a separate factor. Using FA with Varimax rotation, 4 independent factors were identified: "Obesity-INS," "Blood pressure," "Lipids-INS," and "Central obesity." They explained about 60% of the variance present in the original risk variables. CONCLUSION: MetS ethnic differences were identified. Ascertaining for hypertension or T2D increased the MetS prevalence in networks compared with the one in the US general population. Obesity was the most prominent risk factor contributing to both c-MetS and q-MetS. INS contributed in two important factors (obesity and lipids). The information imbedded into c-MetS trait /q-MetS factors scores can contribute in future research of the MetS, especially its utilization in the genetic analysis
Effect of soluble complement receptor type 1 on reperfusion edema and neutrophil migration after lung allotransplantation in swine
AbstractObjective: Soluble complement receptor type 1 inhibits complement activation by blocking C3 and C5 convertases of the classical and alternative pathways. We evaluated the effect of soluble complement receptor type 1 on lung allograft reperfusion injury. Methods: Left lung transplantation was performed in 13 weight-matched pigs (25 to 31 kg) after prolonged preservation (20 hours at 1° C). One hour after reperfusion the recipient contralateral right lung was excluded to assess graft function only. Complement activity and C3a levels were measured after reperfusion and at the end of the assessment. Extravascular lung water index, intrathoracic blood volume, and cardiac output were assessed during a 5-hour observation period. Gas exchange and hemodynamics were monitored. At the end of the 5-hour assessment period, myeloperoxidase assay and bronchoalveolar lavage were performed to assess neutrophil migration, and C5b-9 (membrane attack complex) deposits in the allograft were detected by immunohistochemistry. Two groups were studied. In group II (n = 6) recipient animals were treated with soluble complement receptor type 1 (15 mg/kg) 15 minutes before reperfusion. Group I (n = 7) served as the control group. Results: Serum complement activity was completely inhibited in group II. In contrast to group I, C5b-9 complexes were not detected in group II allograft tissue samples. C3a was reduced to normal levels in group II (p = 0.00005). Extravascular lung water index was higher in group I animals throughout the assessment period (p = 0.035). No significant difference in allograft myeloperoxidase activity (p = 0.10) and polymorphonuclear leukocyte count of the bronchoalveolar lavage fluid (p = 0.057) was detected. Conclusion: Inhibition of the complement system by soluble complement receptor type 1 blocks local complement activation in the allograft and reduces posttransplantation reperfusion edema but does not improve hemodynamic parameters. (J Thorac Cardiovasc Surg 1998;116:90-7
Mechanically triggered on-demand degradation of polymers synthesized by radical polymerizations
Polymers that degrade on demand have the potential to facilitate chemical recycling, reduce environmental pollution and are useful in implant immolation, drug delivery or as adhesives that debond on demand. However, polymers made by radical polymerization, which feature all carbon-bond backbones and constitute the most important class of polymers, have proven difficult to render degradable. Here we report cyclobutene-based monomers that can be co-polymerized with conventional monomers and impart the resulting polymers with mechanically triggered degradability. The cyclobutene residues act as mechanophores and can undergo a mechanically triggered ring-opening reaction, which causes a rearrangement that renders the polymer chains cleavable by hydrolysis under basic conditions. These cyclobutene-based monomers are broadly applicable in free radical and controlled radical polymerizations, introduce functional groups into the backbone of polymers and allow the mechanically gated degradation of high-molecular-weight materials or cross-linked polymer networks into low-molecular-weight species. (Figure presented.
Effect of TiO2 on the Gas Sensing Features of TiO2/PANi Nanocomposites
A nanocomposite of titanium dioxide (TiO2) and polyaniline (PANi) was synthesized by in-situ chemical polymerization using aniline (ANi) monomer and TiCl4 as precursors. SEM pictures show that the nanocomposite was created in the form of long PANi chains decorated with TiO2 nanoparticles. FTIR, Raman and UV-Vis spectra reveal that the PANi component undergoes an electronic structure modification as a result of the TiO2 and PANi interaction. The electrical resistor of the nanocomposite is highly sensitive to oxygen and NH3 gas, accounting for the physical adsorption of these gases. A nanocomposite with around 55% TiO2 shows an oxygen sensitivity of 600â700%, 20â25 times higher than that of neat PANi. The n-p contacts between TiO2 nanoparticles and PANi matrix give rise to variety of shallow donors and acceptor levels in the PANi band gap which enhance the physical adsorption of gas molecules
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