Sole infection by human metapneumovirus among children with radiographically diagnosed community-acquired pneumonia in a tropical region

Background Limited information is available on the role of human metapneumovirus (HMPV) as the unique pathogen among children hospitalized for community-acquired pneumonia (CAP) in a tropical region. Objective We aimed to describe HMPV infection among children with CAP investigating bacterial and viral co-infections. Patients and methods A prospective study was carried out in Salvador, North-East Brazil. Overall, 268 children aged <5 years hospitalized for CAP were enrolled. Human metapneumovirus RNA was detected in nasopharyngeal aspirates (NPA) by reverse transcription polymerase chain reaction. Sixteen other bacterial and viral pathogens were investigated by an expanded panel of laboratory methods. Chest X-ray taken on admission was read by an independent paediatric radiologist unaware of clinical information or the established aetiology. Results Human metapneumovirus RNA was detected in NPAs of 11 (4.1%) children, of which 4 (36%) had sole HMPV infection. The disease was significantly shorter among patients with sole HMPV infection in comparison with patients with mixed infection (4 +/- 1 versus 7 +/- 2 days, P = 0.03). Three of those four patients had alveolar infiltrates. Conclusion Sole HMPV infection was detected in children with CAP in Salvador, North-East Brazil. HMPV may play a role in the childhood CAP burden.

Hospital-acquired human bocavirus in infants

Human bocavirus (HBoV) is a respiratory pathogen that affects young children. We screened 511 nasopharyngeal aspirates for hospital-acquired HBoV from infants hospitalised with respiratory infection from January to December 2008. Among 55 children with HBoV infection, 10 cases were hospital-acquired. Compared with the community-acquired cases, coinfection with other respiratory viruses in these patients was uncommon. HBoV should be considered for inclusion in screening protocols for nosocomial childhood respiratory infections, especially in intensive care units. (C) 2010 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

The role of respiratory viral infections among children hospitalized for community-acquired pneumonia in a developing country

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.

Procalcitonin is useful in identifying bacteraemia among children with pneumonia

Empirical antibiotic use is prescribed in managing children with pneumonia worldwide. We assessed the usefulness of procalcitonin (PCT) and interferon-alpha (IFN-alpha) in differentiating viral from bacterial pneumonia. Among 159 hospitalized children, pneumonia was diagnosed based on clinical complaints plus pulmonary infiltrate. Aetiology was investigated for 9 viruses and 4 atypical and 3 typical bacteria. PCT and IFN-alpha were measured in the serum sample collected on admission. Eight patients had bacteraemic infections, 38 had non-bacteraemic typical infections, and 19 patients had atypical bacterial infections. Viral and unknown aetiology was established in 57 (36%) and 34 (21%) cases, respectively. Three patients with bacterial infection without collected blood culture were excluded. IFN-alpha (IU/ml) was detectable in 20 (13%) cases. The difference among median PCT values of the bacteraemic (4.22; 1.56-7.56), non-bacteraemic typical bacterial (1.47; 0.24-4.07), atypical bacterial (0.18; 0.06-1.03) and only viral (0.65; 0.11-2.22) subgroups was significant (p = 0.02). PCT was >= 2 ng/ml in 52 (33%) cases. The presence of IFN-alpha was associated with PCT <2 ng/ml (90% vs. 64%, p = 0.02). The negative predictive value (95% confidence interval) of PCT >= 2 ng/ml was 95% (89-100%), 89% (78-100%), 93% (85-100%) for differentiation of bacteraemic from viral, atypical bacterial and non-bacteraemic typical bacterial infection, respectively, and 58% (49-68%) for differentiation between bacterial and viral infection. PCT may be useful in identifying bacteraemia among children hospitalized with community-acquired pneumonia. IFN-alpha was uncommonly detected.

Effects of physiotherapy on hemodynamic variables in newborns with Acute Respiratory Distress Syndrome

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.

One-step reverse transcriptase polymerase chain reaction for the diagnosis of respiratory syncytial virus in children

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.

Pulmonary Surfactant in Respiratory Syncytial Virus Bronchiolitis: The Role in Pathogenesis and Clinical Implications

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.

Long-range ozone transport and its impact on respiratory and cardiovascular health in the north of Portugal

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.

MITOCHONDRIAL RESPIRATORY CHAIN AND CREATINE KINASE ACTIVITIES IN mdx MOUSE BRAIN

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

Modulatory effect of fatty acids on fungicidal activity, respiratory burst and TNF-alpha and IL-6 production in J774 murine macrophages

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.

Anesthetic Activation of Central Respiratory Chemoreceptor Neurons Involves Inhibition of a THIK-1-Like Background K(+) Current

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.

Expression and purification of human respiratory syncytial virus recombinant fusion protein

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.

Genetic Variability of Human Metapneumovirus Isolated From Chilean Children, 2003-2004

Human metapneumovirus (hMPV) is a significant cause of acute lower respiratory tract infection in all age groups, particularly in children. Two genetic groups and four subgroups of hMPV have been described. They co-circulate during an epidemic in variable proportions. The aims were to characterize the genotypes of hMPV recovered from children hospitalized for acute lower respiratory tract infection and to establish the molecular epidemiology of strains circulating in Santiago of Chile during a 2-year period. The detection of the N gene by reverse-transcription polymerase chain reaction was carried out for screening 545 infants hospitalized for acute lower respiratory tract infection in Santiago during 2003-2004. The genetic typing of hMPV was performed by analyzing the fusion gene sequences. hMPV was detected in 10.2% (56/545 cases). Phylogenetic analysis of F gene sequences from 39 Chilean hMPV strains identified the two groups and four subgroups previously described. Strains clustered into group A were split further into the sub lineages A1, A2, and A3. Most Chilean strains clustered into the proposed novel A3 sub lineage (59%). A3 viruses were present in both years, while A1 and A2 circulated just in I year. In conclusion, hMPV is a relevant cause of acute lower respiratory infection in Chilean children and the potential novel cluster of group A emphasize the need for further regional genetic variability studies. J. Med. Virol. 81:340-344, 2009. (c) 2008 Wiley-Liss, Inc.

Characterization of Paracoccidioides brasiliensis COX9, COX12, and COX16 respiratory genes

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.

Gene optimization leads to robust expression of human respiratory syncytial virus nucleoprotein and phosphoprotein in human cells and induction of humoral immunity in mice

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.