968 resultados para Respiratory chemoreception


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Coronaviruses (CoV), like other positive-stranded RNA viruses, redirect and rearrange host cell membranes for use as part of the viral genome replication and transcription machinery. Specifically, coronaviruses induce the formation of double-membrane vesicles in infected cells. Although these double-membrane vesicles have been well characterized, the mechanism behind their formation remains unclear, including which viral proteins are responsible. Here, we use transfection of plasmid constructs encoding full-length versions of the three transmembrane-containing nonstructural proteins (nsps) of the severe acute respiratory syndrome (SARS) coronavirus to examine the ability of each to induce double-membrane vesicles in tissue culture. nsp3 has membrane disordering and proliferation ability, both in its full-length form and in a C-terminal-truncated form. nsp3 and nsp4 working together have the ability to pair membranes. nsp6 has membrane proliferation ability as well, inducing perinuclear vesicles localized around the microtubule organizing center. Together, nsp3, nsp4, and nsp6 have the ability to induce double-membrane vesicles that are similar to those observed in SARS coronavirus-infected cells. This activity appears to require the full-length form of nsp3 for action, as double-membrane vesicles were not seen in cells coexpressing the C-terminal truncation nsp3 with nsp4 and nsp6. IMPORTANCE Although the majority of infections caused by coronaviruses in humans are relatively mild, the SARS outbreak of 2002 to 2003 and the emergence of the human coronavirus Middle Eastern respiratory syndrome (MERS-CoV) in 2012 highlight the ability of these viruses to cause severe pathology and fatality. Insight into the molecular biology of how coronaviruses take over the host cell is critical for a full understanding of any known and possible future outbreaks caused by these viruses. Additionally, since membrane rearrangement is a tactic used by all known positive-sense single-stranded RNA viruses, this work adds to that body of knowledge and may prove beneficial in the development of future therapies not only for human coronavirus infections but for other pathogens as well.

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Respiratory infections represent the fourth most common cause of all deaths across age groups and countries. Treating these infections appropriately is a clear clinical priority and here we outline the types of therapy that are in current use for some of these infections. It is important that treatments are further improved and the potential of inhaled delivery to fulfil this need is considered. We describe novel methodologies that are being applied for the identification and enumeration of microorganisms in the respiratory tract, and propose that ways of improving therapy may arise from understanding better the etiology of respiratory infection and the impact of inhaled drug therapies. The potential for translational benefits for patients are also discussed.

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We report an investigation for 16 bacteria and viruses among 184 children hospitalized with pneumonia in Salvador, Brazil. Etiology was established in 144 (78%) cases. Viral, bacterial, and mixed infections were found in 110 (60%), 77 (42%), and 52 (28%) patients, respectively. Rhinovirus (21%) and Streptococcus pneumoniae (21%) were the most common pathogens. Our results demonstrate the importance of viral and pneumococcal infections among those patients.

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Background: Acute respiratory distress syndrome (ARDS) is a frequent respiratory disturbance in preterm newborns. Preceding investigations evaluated chronic physiotherapy effects on newborns with different lung diseases; however, no study analyzed acute physiotherapy treatment on premature newborns with ARDS. In this study we aimed to evaluate the acute effects of chest and motor physiotherapy treatment on hemodynamic variables in preterm newborns with ARDS. Methods: We evaluated heart rate (HR), respiratory rate (RR), systolic (SAP), mean (MAP) and diastolic arterial pressure (DAP), temperature and oxygen saturation (SO(2)%) in 44 newborns with ARDS. We compared all variables between six periods in one day: before first physiotherapy treatment vs. after first physiotherapy treatment vs. before second physiotherapy treatment vs. after second physiotherapy treatment vs. before third physiotherapy treatment vs. after third physiotherapy treatment. Variables were measured 2 minutes before and 5 minutes after each physiotherapy session. We applied Anova one way followed by post hoc Bonferroni test. Results: HR (147.5 +/- 9.5 bpm vs. 137.7 +/- 9.3 bpm; p<0.001), RR (45.5 +/- 8.7cpm vs. 41.5 +/- 6.7 cpm; p=0.001), SAP (70.3 +/- 10.4 mmHg vs. 60.1 +/- 7.1 mmHg; p=0.001) and MAP (55.7 +/- 10 mmHg vs. 46 +/- 6.6 mmHg; p=0.001) were significantly reduced after the third physiotherapy treatment compared to before the first session. There were no significant changes regarding temperature, DAP and SO(2) %. Conclusion: Chest and motor physiotherapy acutely improves HR, RR, SAP, MAP and SO(2) % in newborns with ARDS.

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Human respiratory syncytial virus (HRSV) is the main cause of acute lower respiratory tract infections in infants and children. Rapid diagnosis is required to permit appropriate care and treatment and to avoid unnecessary antibiotic use. Reverse transcriptase (RT-PCR) and indirect immunofluorescence assay (IFA) methods have been considered important tools for virus detection due to their high sensitivity and specificity. In order to maximize use-simplicity and minimize the risk of sample cross-contamination inherent in two-step techniques, a RT-PCR method using only a single tube to detect HRSV in clinical samples was developed. Nasopharyngeal aspirates from 226 patients with acute respiratory illness, ranging from infants to 5 years old, were collected at the University Hospital of the University of Sao Paulo (HU-USP), and tested using IFA, one-step RT-PCR, and semi-nested RT-PCR. One hundred and two (45.1%) samples were positive by at least one of the three methods, and 75 (33.2%) were positive by all methods: 92 (40.7%) were positive by one-step RT-PCR, 84 (37.2%) by IFA, and 96 (42.5%) by the semi-nested RT-PCR technique. One-step RT-PCR was shown to be fast, sensitive, and specific for RSV diagnosis, without the added inconvenience and risk of false positive results associated with semi-nested PCR. The combined use of these two methods enhances HRSV detection. (C) 2007 Elsevier B.V. All rights reserved.

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Respiratory syncytial virus (RSV) bronchiolitis is the leading cause of lower respiratory tract infection, and the most frequent reason for hospitalization among infants throughout the world. In addition to the acute consequences of the disease, RSV bronchiolitis in early childhood is related to further development of recurrent wheezing and asthma. Despite the medical and economic burden of the disease, therapeutic options are limited to supportive measures, and mechanical ventilation in severe cases. Growing evidence suggests an important role of changes in pulmonary surfactant content and composition in the pathogenesis of severe RSV bronchiolitis. Besides the well-known importance of pulmonary surfactant in maintenance of pulmonary homeostasis and lung mechanics, the surfactant proteins SP-A and SP-D are essential components of the pulmonary innate immune system. Deficiencies of such proteins, which develop in severe RSV bronchiolitis, may be related to impairment in viral clearance, and exacerbated inflammatory response. A comprehensive understanding of the role of the pulmonary surfactant in the pathogenesis of the disease may help the development of new treatment strategies. We conducted a review of the literature to analyze the evidences of pulmonary surfactant changes in the pathogenesis of severe RSV bronchiolitis, its relation to the inflammatory and immune response, and the possible role of pulmonary surfactant replacement in the treatment of the disease. Pediatr Pulmonol. 2011; 46:415-420. (c) 2010 Wiley-Liss, Inc.

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Ozone dynamics depend on meteorological characteristics such as wind, radiation, sunshine, air temperature and precipitation. The aim of this study was to determine ozone trajectories along the northern coast of Portugal during the summer months of 2005, when there was a spate of forest fires in the region, evaluating their impact on respiratory and cardiovascular health in the greater metropolitan area of Porto. We investigated the following diseases, as coded in the ninth revision of the International Classification of Diseases: hypertensive disease (codes 401-405); ischemic heart disease (codes 410-414); other cardiac diseases, including heart failure (codes 426-428); chronic obstructive pulmonary disease and allied conditions, including bronchitis and asthma (codes 490-496); and pneumoconiosis and other lung diseases due to external agents (codes 500-507). We evaluated ozone data from air quality monitoring stations in the study area, together with data collected through HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model analysis of air mass circulation and synoptic-scale zonal wind from National Centers for Environmental Prediction data. High ozone levels in rural areas were attributed to the dispersion of pollutants induced by local circulation, as well as by mesoscale and synoptic scale processes. The fires of 2005 increased the levels of pollutants resulting from the direct emission of gases and particles into the atmosphere, especially when there were incoming frontal systems. For the meteorological case studies analyzed, peaks in ozone concentration were positively associated with higher rates of hospital admissions for cardiovascular diseases, although there were no significant associations between ozone peaks and admissions for respiratory diseases.

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In this study we investigated energy metabolism in the mdx mouse brain. To this end, prefrontal cortex, cerebellum, hippocampus, striatum, and cortex were analyzed. There was a decrease in Complex I but not in Complex 11 activity in all structures. There was an increase in Complex III activity in striatum and a decrease in Complex IV activity in prefrontal cortex and striatum. Mitochondrial creatine kinase activity was increased in hippocampus, prefrontal cortex, cortex, and striatum. Our results indicate that there is energy metabolism dysfunction in the mdx mouse brain. Muscle Nerve 41: 257-260, 2010

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The reported effects of different families of fatty acids (FA; SFA, MUFA, n-3 and n-6 PUFA) on human health and the importance of macrophage respiratory burst and cytokine release to immune defence led us to examine the influence of palmitic acid (PA), oleic acid (OA), linoleic acid, arachidonic acid, EPA and DHA on macrophage function. We determined fungicidal activity, reactive oxygen species (ROS) and cytokine production after the treatment of J774 cells with non-toxic concentrations of the FA. PA had a late and discrete stimulating effect on ROS production, which may be associated with the reduced fungicidal activity of the cells after treatment with this FA. OA presented a sustained stimulatory effect on ROS production and increased fungicidal activity of the cells, suggesting that enrichment of diets with OA may be beneficial for pathogen elimination. The effects of PUFA on ROS production were time-and dose-dependently regulated, with no evident differences between n-3 and n-6 PUFA. It was worth noting that most changes induced after stimulation of the cells with lipopolysaccharide were suppressed by the FA. The present results suggest that supplementation of the diet with specific FA, not classes of FA, might enable an improvement in host defence mechanisms or a reduction in adverse immunological reactions.

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At surgical depths of anesthesia, inhalational anesthetics cause a loss of motor response to painful stimuli (i.e., immobilization) that is characterized by profound inhibition of spinal motor circuits. Yet, although clearly depressed, the respiratory motor system continues to provide adequate ventilation under these same conditions. Here, we show that isoflurane causes robust activation of CO(2)/pH-sensitive, Phox2b-expressing neurons located in the retrotrapezoid nucleus (RTN) of the rodent brainstem, in vitro and in vivo. In brainstem slices from Phox2b-eGFP mice, the firing of pH-sensitive RTN neurons was strongly increased by isoflurane, independent of prevailing pH conditions. At least two ionic mechanisms contributed to anesthetic activation of RTN neurons: activation of an Na(+)-dependent cationic current and inhibition of a background K(+) current. Single-cell reverse transcription-PCR analysis of dissociated green fluorescent protein-labeled RTN neurons revealed expression of THIK-1 (TWIK-related halothane-inhibited K(+) channel, K(2P)13.1), a channel that shares key properties with the native RTN current (i.e., suppression by inhalational anesthetics, weak rectification, inhibition by extracellular Na(+), and pH-insensitivity). Isoflurane also increased firing rate of RTN chemosensitive neurons in urethane-anesthetized rats, again independent of CO(2) levels. In these animals, isoflurane transiently enhanced activity of the respiratory system, an effect that was most prominent at low levels of respiratory drive and mediated primarily by an increase in respiratory frequency. These data indicate that inhalational anesthetics cause activation of RTN neurons, which serve an important integrative role in respiratory control; the increased drive provided by enhanced RTN neuronal activity may contribute, in part, to maintaining respiratory motor activity under immobilizing anesthetic conditions.

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The Human Respiratory Syncytial Virus (HRSV) fusion protein (F) was expressed in Escherichia call BL21A using the pET28a vector at 37 degrees C. The protein was purified from the soluble fraction using affinity resin. The structural quality of the recombinant fusion protein and the estimation of its secondary structure were obtained by circular dichroism. Structural models of the fusion protein presented 46% of the helices in agreement with the spectra by circular dichroism analysis. There are only few studies that succeeded in expressing the HRSV fusion protein in bacteria. This is a report on human fusion protein expression in E. call and structure analysis, representing a step forward in the development of fusion protein F inhibitors and the production of antibodies. (c) 2008 Elsevier Inc. All rights reserved.

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Paracoccidioides brasiliensis is a thermo-dimorphic fungus that is the causative agent of paracoccidioidomyicosis (PCM), a human systemic granulomatous mycosis found in Latin America. Dimorphic transition from mycelium to yeast is required for establishing pathogenicity. Dimorphism is marked by changes in mitochondrial physiology, including modulation of respiration rate. In this work, we present the identification of three P. brasiliensis nuclear genes PbCOX9, PbCOX12, and PbCOX16 that code for structural sub-units and a putative assembly facilitator (PbCOX16) of the mitochondrial cytochrome c oxidase (COX), the terminal enzyme complex of the respiratory chain. We measured their expression pattern during the dimorphic transition from mycelium to yeast and back by real-time reverse transcription quantitative polymerase chain reaction (real-time RT-qPCR). Our results show that messages from these genes increase during the mycelium to yeast transition and decrease during the opposite conversion. This result supports active mitochondrial participation in the transition. Heterologous complementation of the corresponding Saccharomyces cerevisiae null mutant with the PbCOX9 gene was successfully obtained. (C) 2008 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

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Human respiratory syncytial virus (HRSV) is the major pathogen leading to respiratory disease in infants and neonates worldwide. An effective vaccine has not yet been developed against this virus, despite considerable efforts in basic and clinical research. HRSV replication is independent of the nuclear RNA processing constraints, since the virus genes are adapted to the cytoplasmic transcription, a process performed by the viral RNA-dependent RNA polymerase. This study shows that meaningful nuclear RNA polymerase II dependent expression of the HRSV nucleoprotein (N) and phosphoprotein (F) proteins can only be achieved with the optimization of their genes, and that the intracellular localization of N and P proteins changes when they are expressed out of the virus replication context. Immunization tests performed in mice resulted in the induction of humoral immunity using the optimized genes. This result was not observed for the non-optimized genes. In conclusion, optimization is a valuable tool for improving expression of HRSV genes in DNA vaccines. (c) 2009 Elsevier B.V. All rights reserved.

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Objective. To investigate the short-term effects of exposure to particulate matter from biomass burning in the Amazon on the daily demand for outpatient care due to respiratory diseases in children and the elderly. Methods. Epidemiologic study with ecologic time series design. Daily consultation records were obtained from the 14 primary health care clinics in the municipality of Alta Floresta, state of Mato Grosso, in the southern region of the Brazilian Amazon, between January 2004 and December 2005. Information on the daily levels of fine particulate matter was made available by the Brazilian National Institute for Spatial Research. To control for confounding factors ( situations in which a non-causal association between exposure and disease is observed due to a third variable), variables related to time trends, seasonality, temperature, relative humidity, rainfall, and calendar effects ( such as occurrence of holidays and weekends) were included in the model. Poisson regression with generalized additive models was used. Results. A 10 mu g/m(3) increase in the level of exposure to particulate matter was associated with increases of 2.9% and 2.6% in outpatient consultations due to respiratory diseases in children on the 6th and 7th days following exposure. Significant associations were not observed for elderly individuals. Conclusions. The results suggest that the levels of particulate matter from biomass burning in the Amazon are associated with adverse effects on the respiratory health of children.

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Loggerhead sea turtle juveniles (Caretta caretta), pelagic stage, are found in waters of Madeira archipelago. Pelagic turtles are in the main growth phase of their life cycle and consequently higher energy needs. However, knowledge about the ecology of pelagic loggerhead sea turtles is still quite rudimentary, mainly about the mechanisms that lead them to find food in the vast ocean. Studies with other pelagic species, such as procellariiform birds, revealed that the olfactory system play an important role for the detection of feeding areas, through the detection of concentration peaks of DMS (dimethylsulfide), a scent compound that naturally exists in the marine environment and it is related to areas of high productivity. Based on the assumption that loggerhead sea turtles use a similar mechanism, behavioural experiments were conducted in order to analyze the chemoreception capacity to DMS (airborne chemoreception - theoretically responsible for the long distance detection of areas with food patches; and aquatic chemoreception - theoretically responsible for the short distance detection of preys). The first step was to observe if pelagic loggerheads demonstrate sensitivity to DMS and the second was to verify if they really use the DMS, in natural conditions, as an airborne cue to find areas where food patches might be available. Four juveniles of loggerhead sea turtles were tested in captivity and three wild turtles in the open ocean. The results of airborne chemoreception experiments in captivity revealed that one turtle clearly demonstrated sensitivity to DMS and the sea experiments confirmed this result. However, the experiments were not conclusive on the question whether the pelagic turtles actually use the DMS as an airborne cue to detect long distance food patches. In aquatic chemoreception experiments was not observed sensitivity to DMS by the three sea turtles tested. In the classical conditioning experiment, where DMS and food were given nearly at the same time revealed that after a certain period of time, the sea turtle tested did not associated the DMS stimulus with a possible food reward. The main cause of mortality of loggerhead sea turtles in Madeira waters is due to the accidental capture (bycatch) by deep pelagic longlines fishery which the target species is the black-scabbard (Aphanopus carbo) fish. Chub mackerel (Scomber japonicus) is one of the baits used in this fishery. Aquatic chemoreception experiments were conducted in order to evaluate the attractiveness of the chub mackerel for sea turtles. For the three sea turtles tested, the results showed that in 90% of the cases the sea turtles were extremely attracted by the underwater smell of this fish.