Acute respiratory distress syndrome (ARDS) can emerge from certain pathologies, such as sepsis, fat embolism and leptospirosis, in which the levels of unesterified fatty acids are increased in the ...patient's plasma. ARDS is characterized by edema formation, and edema resolution occurs mainly due to the pneumocyte Na/K-ATPase activity. As previously described, increased oleic acid (OA) plasma concentrations induce lung injury by interfering with sodium transport. The first aim of this study was to develop a radioactivity-free assay to detect Na,K-ATPase activity ex vivo using a model of OA-induced lung injury in mice. We also investigated the relationship between Na/K-ATPase inhibition and OA-induced lung injury using ouabain-induced lung injury as a comparison, because of the well-described effect of ouabain as a Na/K-ATPase inhibitor.
We developed a Na/K-ATPase assay based on the capture of non-radioactive Rb+ ions by mice lung tissue in the absence or presence of ouabain, a specific Na/K-ATPase inhibitor. Rb+ incorporation into the lung was measured by inductively coupled plasma-optical emission spectrometry (ICP-OES) after lung tissue mineralization. Na/K-ATPase activity was considered as the difference between Rb+ incorporation in the absence and in the presence of ouabain. Bronchoalveolar lavage fluid was collected for lung injury assessment. For this assessment, cell counting, lipid body enumeration and lipid mediator concentrations were measured. Histological analyses were used to determinate lung pathology. Whole body plethysmographic analysis was performed to assay lung function.
The lung Na/K-ATPase activity of mice was completely inhibited by an OA dose of 10 μmol, an effect also obtained with 10-3 μmol of ouabain, as demonstrated by the decreased Rb+ incorporation in the lungs. The same OA dose induced lung edema and inflammation with cell influx, lipid body formation, and leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) production. Ouabain also induced lung inflammation, as detected by histological examinations. As far as we know, this is the first time that ouabain-induced lung injury was shown. Both OA and ouabain induced functional lung pathology in mice simultaneously with inhibition of the lung Na/K-ATPase activity.
We developed a new non-radioactive assay to quantified Na/K-ATPase in vivo. OA and ouabain inhibited in vivo Na/K-ATPase activity in the lungs and induced lung injury. Our data reinforce the idea that Na/K-ATPase inhibitors may worsen lung injury in specific pathological conditions.
The molecular identity of the mitochondrial pyruvate carrier (MPC) was presented in 2012, forty years after the active transport of cytosolic pyruvate into the mitochondrial matrix was first ...demonstrated. An impressive amount of in vivo and in vitro studies has since revealed an unexpected interplay between one, two, or even three protein subunits defining different functional MPC assemblies in a metabolic-specific context. These have clear implications in cell homeostasis and disease, and on the development of future therapies. Despite intensive efforts by different research groups using state-of-the-art computational tools and experimental techniques, MPCs’ structure-based mechanism remains elusive. Here, we review the current state of knowledge concerning MPCs’ molecular structures by examining both earlier and recent studies and presenting novel data to identify the regulatory, structural, and core transport activities to each of the known MPC subunits. We also discuss the potential application of cryogenic electron microscopy (cryo-EM) studies of MPC reconstituted into nanodiscs of synthetic copolymers for solving human MPC2.
Despite recent advances in cryo-electron microscopy and artificial intelligence-based model predictions, a significant fraction of structure determinations by macromolecular crystallography still ...requires experimental phasing, usually by means of single-wavelength anomalous diffraction (SAD) techniques. Most synchrotron beamlines provide highly brilliant beams of X-rays of between 0.7 and 2 Å wavelength. Use of longer wavelengths to access the absorption edges of biologically important lighter atoms such as calcium, potassium, chlorine, sulfur and phosphorus for native-SAD phasing is attractive but technically highly challenging. The long-wavelength beamline I23 at Diamond Light Source overcomes these limitations and extends the accessible wavelength range to λ = 5.9 Å. Here we report 22 macromolecular structures solved in this extended wavelength range, using anomalous scattering from a range of elements which demonstrate the routine feasibility of lighter atom phasing. We suggest that, in light of its advantages, long-wavelength crystallography is a compelling option for experimental phasing.
Pediatric oncology patients (POP) have a high risk of infections due to impaired immunity. Invasive pneumococcal disease (IPD) is an important cause of severe infection in these patients and it is ...associated with high mortality. This study aimed to evaluate the incidence and risk factors associated with IPD at a Pediatric Oncology Center in Brazil.
This was a retrospective case-control study. All IPD cases in children with cancer from 2005 through 2016 were reviewed. Each case of IPD was matched with two controls from a cohort of patients matched for year of IPD, age and disease in order to assess risk factors. The incidence density was calculated as the number of IPD per 100,000 patients-year.
A total of 51 episodes of IPD in 49 patients was identified. All pneumococci were isolated from blood cultures. The median age was five years and 67% were male; mortality rate was 7.8%. The IPD incidence density rate in POP was 311.21 per 100,000 patients-year, significantly higher than the rate in the general pediatric population. Severe neutropenia was the only risk factor associated with IPD, after multivariate conditional logistic regression analysis.
Although pneumococcal disease decreased after the introduction of 10-valent pneumococcal vaccine in the Brazilian national immunization schedule in 2010, there was no decrease in the IPD incidence rate in our cohort. A higher coverage rate of pneumococcal vaccination in children in the general population might be necessary to reduce the incidence rate in this high-risk population.
Oleic acid (OA) can induce acute lung injury in experimental models. In the present work, we used intratracheal OA injection to show augmented oedema formation, cell migration and activation, lipid ...mediator, and cytokine productions in the bronchoalveolar fluids of Swiss Webster mice. We also demonstrated that OA-induced pulmonary injury is dependent on ERK1/2 activation, since U0126, an inhibitor of ERK1/2 phosphorylation, blocked neutrophil migration, oedema, and lipid body formation as well as IL-6, but not IL-1β production. Using a mice strain carrying a null mutation for the TLR4 receptor, we proved that increased inflammatory parameters after OA challenges were not due to the activation of the TLR4 receptor. With OA being a Na/K-ATPase inhibitor, we suggest the possible involvement of this enzyme as an OA target triggering lung inflammation.
Sepsis is characterized by inflammatory and metabolic alterations, which lead to massive cytokine production, oxidative stress and organ dysfunction. In severe systemic inflammatory response ...syndrome, plasma non-esterified fatty acids (NEFA) are increased. Several NEFA are deleterious to cells, activate Toll-like receptors and inhibit Na+/K+-ATPase, causing lung injury. A Mediterranean diet rich in olive oil is beneficial. The main component of olive oil is omega-9 oleic acid (OA), a monounsaturated fatty acid (MUFA). We analyzed the effect of OA supplementation on sepsis. OA ameliorated clinical symptoms, increased the survival rate, prevented liver and kidney injury and decreased NEFA plasma levels in mice subjected to cecal ligation and puncture (CLP). OA did not alter food intake and weight gain but diminished reactive oxygen species (ROS) production and NEFA plasma levels. Carnitine palmitoyltransferase IA (CPT1A) mRNA levels were increased, while uncoupling protein 2 (UCP2) liver expression was enhanced in mice treated with OA. OA also inhibited the decrease in 5' AMP-activated protein kinase (AMPK) expression and increased the enzyme expression in the liver of OA-treated mice compared to septic animals. We showed that OA pretreatment decreased NEFA concentration and increased CPT1A and UCP2 and AMPK levels, decreasing ROS production. We suggest that OA has a beneficial role in sepsis by decreasing metabolic dysfunction, supporting the benefits of diets high in monounsaturated fatty acids (MUFA).
This experiment presents a manual-observing procedure as an inexpensive alternative for investigating stimulus control and establishing equivalence classes in a matching-to-sample task (MTS). To ...illustrate the procedure, we evaluated the effects of different MTS training structures on observing responses and equivalence class formation. Participants had to press a button below each covered sample and comparison stimuli to reveal the stimulus. Four participants were exposed to two different sequences of the many-to-one (MTO) and one-to-many (OTM) procedures, using the manual-observing procedure during training and testing. The results showed that the manual-observing procedure allowed participants to acquire conditional discriminations and form equivalence classes, suggesting that the use of manual-observing responses in an MTS procedure is a useful procedure to evaluate stimulus control in an MTS task.
The present article describes how to use the computer program
to help assemble complete datasets for the solution of macromolecular structures, starting from partial or complete datasets, derived ...from data collection from multiple crystals. The program is demonstrated on more than two hundred X-ray diffraction datasets obtained from 50 crystals of a complex formed between the SRF transcription factor, its cognate DNA, and a peptide from the SRF cofactor MRTF-A. This structure is currently in the process of being fully solved. While full details of the structure are not yet available, the repeated application of
on data from this structure, as they have become available, has made it possible to produce electron density maps clear enough to visualise the potential location of MRTF sequences.
Effective and long-term combined antiretroviral therapy (cART) has decreased morbidity and mortality in HIV-infected individuals. Despite treatment advances, HIV-infected children continue to develop ...noninfectious conditions, including liver fibrosis.
Cross-sectional study designed to identify liver fibrosis in HIV-infected adolescents and young adults, in an outpatients clinic of Pediatric Infectious Diseases Division at Escola Paulista de Medicina/Universidade Federal de São Paulo (UNIFESP), diagnosed by noninvasive methods (liver elastography–FibroScan®, APRI and FIB4). Variables examined included demographics, clinical, laboratories, HIV treatment. All participants underwent FibroScan® to measure liver parenchyma elasticity. Values equal to above 7.0 kPa were interpreted as the presence of significant liver fibrosis. Two different biomarkers of liver fibrosis were employed: the AST-to-Platelet Ratio Index (APRI) and the Fibrosis-4 score (FIB-4). APRI values above 1.5 have been considered as levels of clinically significant liver fibrosis and FIB-4 values above 3.25 suggested the presence of advanced fibrosis.
Between August 2014 and March 2017, the study enrolled 97 patients, age 10–27 years old, fourteen of 97 subjects (14.4%) presented liver stiffness (≥7 kPa) detected by the liver elastography. No patient had APRI> 1.5. No patient had FIB4 value > 3.25. The only isolated laboratory parameter that could be significantly associated with high liver stiffness was thrombocytopenia (p = 0.022, Fisher's exact test).
Liver stiffness was identified in 14.4% (14/97) of this cohort by liver elastography. Liver disease in HIV-infected adolescents and young adults manifests itself silently, so should be routinely investigated.
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