Temperature Dependence of Hydrogen Bond Networks of Liquid Water: Thermodynamic Properties and Structural Heterogeneity from Topological Descriptors.

Topological analyses of hydrogen bond networks were performed based on the complex network and island statistics of liquid water at different temperatures. The influence of temperature on the liquid water structures and the topological properties of the hydrogen bond networks was investigated by Metropolis Monte Carlo simulations with the TIP4P/2005 potential model. The bilinear behavior of the second peak in the radial distribution function with the temperature was properly reproduced by these simulations. The average connectivity also displayed a bilinear behavior consistent with being a local descriptor. The semiglobal average path length (or geodesic distance) descriptor showed an unprecedented trimodal distribution, whose areas were dependent on the temperature. Considering equilibrium between these three sets of networks, standard enthalpy and entropy of equilibrium were determined for the first time, providing new insights into the structural heterogeneities of liquid water with interesting perspectives for modeling these quantitative properties of hydrogen bond networks.

Shorter telomeres in children with severe asthma, an indicative of accelerated aging.

Severe therapy-resistant asthma (STRA) is closely associated with distinct clinical and inflammatory pheno-endotypes, which may contribute to the development of age-related comorbidities. Evidence has demonstrated a contribution of accelerated telomere shortening on the poor prognosis of respiratory diseases in adults. Eotaxin-1 (CCL11) is an important chemokine for eosinophilic recruitment and the progression of asthma. In the last years has also been proposed as an age-promoting factor. This study aimed to investigate the association of relative telomere length (rTL) and eotaxin-1 in asthmatic children. Children aged 8-14 years (n=267) were classified as healthy control (HC, n=126), mild asthma (MA, n=124) or severe therapy-resistant asthma (STRA, n=17). rTL was performed by qPCR from peripheral blood. Eotaxin-1 was quantified by ELISA from fresh-frozen plasma. STRA had shorter telomeres compared to HC (p=0.02) and MA (p=0.006). Eotaxin-1 levels were up-regulated in STRA [median; IQR25-75)] [(1,190 pg/mL; 108-2,510)] compared to MA [(638 pg/mL; 134-1,460)] (p=0.03) or HC [(627 pg/mL; 108-1,750)] (p<0.01). Additionally, shorter telomeres were inversely correlated with eotaxin-1 levels in STRA (r=-0.6, p=0.013). Our results suggest that short telomeres and up-regulated eotaxin-1, features of accelerated aging, could prematurely contribute to a senescent phenotype increasing the risk for early development of age-related diseases in asthma.

Impact of 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) on childhood pneumonia hospitalizations in Brazil two years after introduction.

INTRODUCTION: Pneumococcal disease is a major public health problem worldwide. From March to September of 2010, 10-valent pneumococcal non-typeable Haemophilus influenzae protein conjugate vaccine (PHiD-CV) was introduced in the Brazilian childhood National Immunization Program (NIP) in all 27 Brazilian states. The aim of the present study is to report national time-trends in incidence of hospital admissions for childhood pneumonia in Brazil before and after two years of introduction of this new pneumococcal conjugate vaccine. METHODS: Analysis of hospitalization data of children aged 0-4 years in Brazilian public health system with an admission diagnosis of pneumonia from 2002 to 2012 was performed comparing pre (2002-2009) and post-vaccination periods (2011-2012). Hospital number of admission due to pneumonia and all non-respiratory diseases were obtained from DATASUS, the Brazilian government open-access public health database system. Incidence of pneumonia hospitalization was compared to incidence of all non-respiratory admissions. RESULTS: Admission rates for pneumonia decreased steadily from 2010 to 2012. In children aged less than four years, incidence of pneumonia hospitalizations decreased 12.65% when pre (2002-2009) and post-vaccination introduction periods (2011-2012) were compared and adjusted for seasonality and secular-trend (p<0.001). On the other hand, non-respiratory admission rates remained stable comparing both periods (p=0.39). CONCLUSION: Childhood pneumonia hospitalization rates were fluctuating prior to 2010 and decreased significantly in the two years after PHiD-CV introduction. Conversely, rate of non-respiratory admissions has shown no decrease. These data are an evidence of the effectiveness and public health impact of this new pneumococcal vaccine.

Chorioamnionitis and subsequent lung function in preterm infants.

OBJECTIVE: To explore the relationship between prematurity, gender and chorioamnionitis as determinants of early life lung function in premature infants. METHODS: Placenta and membranes were collected from preterm deliveries (<37 weeks gestational age) and evaluated for histological chorioamnionitis (HCA). Patients were followed and lung function was performed in the first year of life by Raised Volume-Rapid Thoracic Compression Technique. RESULTS: Ninety-five infants (43 males) born prematurely (median gestational age 34.2 weeks) were recruited. HCA was detected in 66 (69%) of the placentas, and of these 55(58%) were scored HCA Grade 1, and 11(12%) HCA Grade 2. Infants exposed to HCA Grade 1 and Grade 2, when compared to those not exposed, presented significantly lower gestational ages, higher prevalence of RDS, clinical early-onset sepsis, and the use of supplemental oxygen more than 28 days. Infants exposed to HCA also had significantly lower maximal flows. There was a significant negative trend for z-scores of lung function in relation to levels of HCA; infants had lower maximal expiratory flows with increasing level of HCA. (p = 0.012 for FEF50, p = 0.014 for FEF25-75 and p = 0.32 for FEV0.5). Two-way ANOVA adjusted for length and gestational age indicated a significant interaction between sex and HCA in determining expiratory flows (p<0.01 for FEF50, FEF25-75 and p<0.05 for FEV0.5). Post-hoc comparisons revealed that female preterm infants exposed to HCA Grade 1 and Grade 2 had significant lower lung function than those not exposed, and this effect was not observed among males. CONCLUSIONS: Our findings show a sex-specific negative effect of prenatal inflammation on lung function of female preterm infants. This study confirms and expands knowledge upon the known association between chorioamnionitis and early life chronic lung disease.

Simulated self-organization of death by inherited mutations

An agent-based computer simulation of death by inheritable mutations in a changing environment shows a maximal population, or avoids extinction, at some intermediate mutation rate of the individuals. Our results indicate that death seems needed to allow for evolution of the fittest, as required by a changing environment.

Simulação computacional de agentes individuais que se reproduzem e morrem por acúmulo de mutações herdadas mostra um máximo da população ou evita extinção, para taxas de mutação intermediárias. Assim, as mortes parecem necessárias para a evolução dos mais adaptados a um ambiente mutante.

Simulated self-organization of death by inherited mutations.

An agent-based computer simulation of death by inheritable mutations in a changing environment shows a maximal population, or avoids extinction, at some intermediate mutation rate of the individuals. Our results indicate that death seems needed to allow for evolution of the fittest, as required by a changing environment.

Prevalência de sintomas de distúrbios respiratórios do sono em escolares brasileiros / The prevalence of symptoms of sleep-disordered breathing in Brazilian schoolchildren

OBJETIVO: Verificar a prevalência de sintomas de distúrbios respiratórios do sono em crianças de baixo nível socioeconômico no Sul do Brasil. MÉTODOS: Foi realizado um estudo transversal em Uruguaiana (RS), utilizando questionário específico sobre sintomas de distúrbios respiratórios do sono, respondido pelos pais, em uma amostra de escolares de 9 a 14 anos participantes do International Study of Asthma and Allergies in Childhood (ISAAC). RESULTADOS: Foram respondidos 998 questionários de um total de 1.011 escolares elegíveis. Relato de ronco habitual ocorreu em 27,6 por cento das crianças, apnéia em 0,8 por cento, respiração oral diurna em 15,5 por cento e sonolência diurna excessiva em 7,8 por cento. Crianças com sonolência diurna excessiva apresentaram maior risco de ronco habitual (OR = 2,7; IC95 por cento 1,4-5,4), apnéia (OR = 9,9; IC95 por cento 1,2-51), respiração oral (OR = 13,1; IC95 por cento 6,2-27,4) e problemas de aprendizado (OR = 9,9; IC95 por cento 1,9-51,0). Rinite, fumo materno e testes cutâneos alérgicos estiveram significativamente associados a ronco habitual e respiração oral diurna. CONCLUSÕES: A prevalência de sintomas de distúrbios respiratórios do sono é elevada em crianças de 9 a 14 anos na cidade de Uruguaiana. A prevalência de ronco habitual foi quase duas vezes maior que a descrita nessa faixa etária em outras populações. Crianças com sonolência diurna excessiva parecem ter quase 10 vezes mais risco de problemas de aprendizado.

OBJECTIVE: To identify the prevalence of symptoms of sleep-disordered breathing among children of low socioeconomic status in the South of Brazil. METHODS: This was a cross-sectional study, carried out in the city of Uruguaiana, RS, in which specific questionnaire about the symptoms of sleep-disordered breathing was completed by the parents of a sample of schoolchildren aged 9 to 14 years, enrolled on the International Study of Asthma and Allergies in Childhood (ISAAC). RESULTS: From the total of 1,011 eligible schoolchildren, 998 questionnaires were completed. The parents of 27.6 percent of the children reported habitual snoring, while 0.8 percent reported apnea, 15.5 percent described daytime mouth breathing and 7.8 percent complained of excessive daytime sleepiness. Children with excessive daytime sleepiness were at greater risk of habitual snoring (OR = 2.7; 95 percentCI 1.4-5.4), apnea (OR = 9.9; 95 percentCI 1.2-51), mouth breathing (OR = 13.1; 95 percentCI 6.2-27.4) and learning difficulties (OR = 9.9; 95 percentCI 1.9-51.0). Rhinitis, maternal smoking and positive allergy skin test results were significantly associated with habitual snoring and daytime mouth breathing. CONCLUSIONS: There is an elevated prevalence of symptoms of sleep-disordered breathing among children from 9 to 14 in the city of Uruguaiana. The prevalence of habitual snoring was almost twice that described in this age group in other populations. Children with excessive daytime sleepiness appear to have almost 10 times the risk of learning difficulties.

The prevalence of symptoms of sleep-disordered breathing in Brazilian schoolchildren.

OBJECTIVE: To identify the prevalence of symptoms of sleep-disordered breathing among children of low socioeconomic status in the South of Brazil. METHODS: This was a cross-sectional study, carried out in the city of Uruguaiana, RS, in which specific questionnaire about the symptoms of sleep-disordered breathing was completed by the parents of a sample of schoolchildren aged 9 to 14 years, enrolled on the International Study of Asthma and Allergies in Childhood (ISAAC). RESULTS: From the total of 1,011 eligible schoolchildren, 998 questionnaires were completed. The parents of 27.6% of the children reported habitual snoring, while 0.8% reported apnea, 15.5% described daytime mouth breathing and 7.8% complained of excessive daytime sleepiness. Children with excessive daytime sleepiness were at greater risk of habitual snoring (OR = 2.7; 95%CI 1.4-5.4), apnea (OR = 9.9; 95%CI 1.2-51), mouth breathing (OR = 13.1; 95%CI 6.2-27.4) and learning difficulties (OR = 9.9; 95%CI 1.9-51.0). Rhinitis, maternal smoking and positive allergy skin test results were significantly associated with habitual snoring and daytime mouth breathing. CONCLUSIONS: There is an elevated prevalence of symptoms of sleep-disordered breathing among children from 9 to 14 in the city of Uruguaiana. The prevalence of habitual snoring was almost twice that described in this age group in other populations. Children with excessive daytime sleepiness appear to have almost 10 times the risk of learning difficulties.

Growth rate of lung function in healthy preterm infants.

RATIONALE: It remains unclear whether premature birth, in the absence of neonatal respiratory disease, results in abnormal growth and development of the lung. We previously reported that a group of healthy infants born at 32-34 weeks' gestation and without respiratory complications had decreased forced expiratory flows and normal forced vital capacities at 2 months of age. OBJECTIVES: Our current study evaluated whether these healthy infants born prematurely exhibited improvement or "catch-up" in their lung function during the second year of life. METHODS: Longitudinal measurements of forced expiratory flows by the raised volume rapid thoracic compression technique were obtained in the first and the second years of life for infants born prematurely at 32.7 (range, 30-34) weeks' gestation (n = 26) and infants born at full term (n = 24). MEASUREMENTS AND MAIN RESULTS: Healthy infants born prematurely demonstrate decreased forced expiratory flows and normal forced vital capacities in the first and second years of life. In addition, the increases in lung function with growth were similar to full-term infants. CONCLUSIONS: Persistently reduced flows in the presence of normal forced vital capacity and the absence of catch-up growth in airway function suggest that premature birth is associated with altered lung development.

Reduced lung function in healthy preterm infants in the first months of life.

RATIONALE: Preterm delivery has been associated with a higher incidence of respiratory morbidity even in infants that do not have significant respiratory disease during the neonatal period. Reduced flows have been reported in children and adolescents born prematurely. OBJECTIVE: The aim of this study was to assess lung function in healthy preterm infants in the first months of life. METHODS: Preterm infants with less than 48 h of supplemental oxygen were recruited. Lung function was assessed by the raised-volume rapid thoracic compression in the first months of life. The control group consisted of full-term infants without a history of respiratory diseases. MEASUREMENTS AND MAIN RESULTS: Sixty-two preterm (29 male) and 27 full-term (10 male) infants were tested. Adjusting for length, age, and sex, we found a mean significant reduction of 92 ml/s (22%) in FEF(50), 73 ml/s (21%) in FEF(25-75), and 19 ml (28%) in FEV(0.5) in the preterm group. These differences in expiratory flows remained significant using another model that adjusts for lung volume (p < 0.01 for FEF(50), FEF(25-75), and FEV(0.5), and p < 0.05 for FEF(75)). In the preterm group, after adjusting for length, male sex, lower gestational age, and increased weight were significantly and independently associated with reduced flows. CONCLUSIONS: Our findings confirm that prematurity is independently associated with reduced lung function and that this is detectable in the first months of life. Male sex, lower gestational age, and weight are important predictors for reduced expiratory flows in this group.

Effect of Angiostrongylus costaricensis extract on eosinophilic pulmonary response in BALB/c mice.

Epidemiological and experimental studies have demonstrated an association between parasitic infections and the allergic diseases. A protective effect in asthma was shown in animals infected with helminths. The aim of this study was to determine the effect of Angiostrongylus costaricensis extract on inflammatory lung response to ovalbumin (OVA) in mice. Four BALB/c mice received A. costaricensis extract by intraperitoneal (i.p.) injection on the first day. Mice were immunised against OVA by i.p. injection on day (D) 5 and D12 and received a daily intranasal OVA challenge (40 microl) between the D19 and D21. On D23, we performed a bronchoalveolar lavage (BAL) on the mice. Four BALB/c mice (control group) were immunised against OVA using the same protocol, but did not receive parasite extract. Total cell counts (TCC) and differential cell counts were performed in BAL fluid samples. Eosinophil cell counts in BAL fluid were lower in the group that received A. costaricensis extract when compared with the control group (0.04 x 10(6) cells/ml and 0.01 x 10(6) cells/ml, respectively; p=0.04). TCC were not different between the groups studied. A. costaricensis extract in mice decreases eosinophilic response to OVA in BAL fluid.

[Plastic bronchitis in a child with thalassemia alpha]. / Bronquite plástica em criança com talassemia alfa.

OBJECTIVE: Plastic bronchitis is an unusual condition in children, associated with formation of mucofibrinous casts and mucous plugging of the tracheobronchial tree. Given that this illness is part of the differential diagnosis of acute respiratory failure, early treatment is important for improved prognosis. The aim of this report is to describe a case of plastic bronchitis in a child with alpha-thalassemia that was treated successfully with endoscopy. DESCRIPTION: A three year old, black, male child, previously healthy, presented with acute respiratory failure and a chest x-ray showing pulmonary atelectasis. There was no evidence of respiratory symptoms or previous allergy state. The diagnosis of plastic bronchitis was made using flexible and rigid bronchoscopy, and confirmed by histopathologic findings. The child progressed well, treatment was based on supportive care and antibiotics were not used. Ten days after discharge, radiographic appearance was normal. Alpha thalassemia was diagnosed through hemoglobin electrophoresis. COMMENTS: Plastic bronchitis is clinically important because has similar presentation to other prevalent diseases, such as foreign body aspiration and asthma. When plastic bronchitis is suspected, endoscopy is indicated in order to confirm diagnosis and define treatment. Plastic bronchitis has been previously described in patients with cystic fibrosis, cardiac surgery and sickle cell disease. In this case, an association with alpha-thalassemia was observed.

Bronquite plástica em criança com talassemia alfa / Plastic bronchitis in a child with thalassemia alpha

OBJETIVO: A bronquite plástica é uma doença infreqüente na criança, sendo caracterizada por moldes ou cilindros mucofibrinosos na árvore traqueobrônquica. Faz parte do diagnóstico diferencial de crianças com insuficiência respiratória de início agudo, e o tratamento precoce é importante para a resolução do quadro. O objetivo deste relato é descrever um caso de bronquite plástica tratado com sucesso por endoscopia, em paciente portador de talassemia alfa. DESCRIÇÃO: Criança do sexo masculino, 3 anos de idade, sem antecedentes mórbidos significativos, apresentou quadro de insuficiência respiratória aguda, com achados radiológicos de atelectasia pulmonar sugestivos de aspiração de corpo estranho. Não havia sintomas respiratórios ou antecedentes de alergia ou infecções respiratórias de repetição. A realização de broncoscopia flexível, complementada por endoscopia rígida e exame anatomopatológico, evidenciou a presença de bronquite plástica. Após a realização da endoscopia, a criança evoluiu satisfatoriamente, com curva térmica afebril e extubação em 72 horas. Foram utilizadas medicações sintomáticas, sem necessidade de antimicrobianos. Dez dias após a alta, a radiografia de tórax encontrava-se normal. A talassemia alfa foi diagnosticada através da eletroforese de hemoglobina. COMENTARIOS: A importância clínica da bronquite plástica reside no fato de apresentar um quadro semelhante ao de outras doenças mais prevalentes, como a aspiração de corpo estranho e a asma brônquica. A suspeita do quadro recomenda a realização de endoscopia para diagnóstico e tratamento. É reconhecida a ocorrência de bronquite plástica em crianças com fibrose cística, pós-operatório de cirurgia cardíaca e anemia falciforme. No presente artigo, foi observada uma associação com talassemia alfa.

Levels of Th1 and Th2 cytokines in children with post-infectious bronchiolitis obliterans.

BACKGROUND: Post-infectious bronchiolitis obliterans (BO) is a chronic obstructive airway disease associated with inflammation and fibrosis of the small airways; it is more common in children who have had acute viral bronchiolitis. No previous studies have reported the immune response of BO. Unbalanced Th1/Th2 immune response might be one of the risk factors for developing this illness. AIM: To compare the production of interferon (IFN)-gamma, interleukin (IL)-4 and IL-10 in peripheral blood mononuclear cell cultures in children with BO and in healthy children. METHODS: From March 2003 to October 2003, children with BO and healthy children were selected from the paediatric outpatient clinics in our centre. Peripheral blood was collected and mononuclear cells were separated and cultured (96 hours) with 1% phytohaemagglutinin stimulation. The supernatant was stored and cytokine levels were measured through ELISA. RESULTS: IFN-gamma, IL-4 and IL-10 levels were not significantly different between the groups studied. Family history of atopy was significantly associated with subjects with BO (p=0.02). CONCLUSIONS: Our results suggest that unbalanced peripheral blood Th1/Th2 immune response of children with post-infectious BO might not be associated with its pathophysiology. Further studies are required to better understand the role of risk factors, including viral genotype, viral load or tissue repair abnormalities in the development of post-infectious BO.

[Rhinovirus and acute bronchiolitis in young infants]. / Bronquiolite aguda por rinovírus em lactentes jovens.

OBJECTIVE: To determine the prevalence of rhinovirus infection in hospitalized young infants with acute bronchiolitis. METHODS: Hospitalized children with acute bronchiolitis admitted to the Hospital São Lucas/PUCRS between May and September 2002 were selected prospectively. Nasopharyngeal samples were assayed for respiratory syncytial virus, parainfluenza, influenza and adenovirus by immunofluorescence. For rhinovirus test a reverse transcription-polymerase chain reaction for picornavirus was used, followed by hybridization with rhinovirus specific probes. RESULTS: Forty-five patients were selected for the study. The median age of the subjects studied was 2 months. Positive samples for respiratory viruses were found in 35/45 (77.8%) subjects and 7/35 (20%) patients had dual infection. Respiratory syncytial virus was detected in 33/35 (94%) cases. Rhinovirus was detected in 6/35 patients (17%). CONCLUSIONS: Rhinovirus was the second most common agent detected in nasal secretions from young infants hospitalized with acute bronchiolitis.

Bronquiolite aguda por rinovírus em lactentes jovens / Rhinovirus and acute bronchiolitis in young infants

OBJETIVO: Determinar a prevalência de infecção por rinovírus em lactentes menores de 6 meses hospitalizados por bronquiolite aguda. MÉTODOS: Foram selecionados de forma prospectiva lactentes hospitalizados com diagnóstico de bronquiolite aguda, no Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul, no período entre maio e setembro de 2002. Foi pesquisada a presença de vírus respiratórios no aspirado nasofaríngeo (ANF), através de imunofluorescência direta para vírus sincicial respiratório, parainfluenza, influenza e adenovírus. Para detecção do rinovírus, foi utilizada a reação de transcrição reversa, seguida de reação em cadeia da polimerase, específicas para picornavírus, seguidas de hibridização com sonda específica para rinovírus. RESULTADOS: Foram selecionados 45 lactentes hospitalizados com diagnóstico de bronquiolite aguda. A mediana da idade dos pacientes selecionados foi de 2 meses. Foram encontradas amostras positivas para vírus respiratórios em 35/45 (77,8 por cento) casos. Foi detectado mais de um vírus em 7/35 (20 por cento) amostras. Das amostras positivas, o vírus sincicial respiratório foi detectado em 33/35 (94 por cento) casos. O rinovírus foi detectado em 6/35 casos (17 por cento). CONCLUSÕES: O rinovírus foi o segundo agente mais freqüentemente detectado em secreção nasal de lactentes jovens hospitalizados por bronquiolite aguda.

Influência do critério de diagnóstico na prevalência de dermatite atópica / Influence of diagnostic criteria in atopic eczema prevalence

O objetivo deste artigo é determinar a prevalência de dermatite atópica (DA), conforme dois diferentes critérios de diagnósticos epidemiológico, em uma amostra de escolares da cidade de Gravataí, RS. Neste estudo transversal, os autores comparam a prevalência de DA medida por dois diferentes métodos de diagnóstico. O estudo foi realizado com a amostra de crianças de 9 a 12 anos, escolhida aleatoriamente, pertencente à rede de escolas públicas da cidade de Gravataí, RS. A medida de prevalência de DA baseada em um único dado do questionário do ISAAC (International Study of Asthma and Allergies in Childhood) foi respondido pelos pais ou responsáveis e perguntava sobre sintomas de dermatose da criança, nos últimos 12 meses. O outro método de diagnóstico (critério UK) utilizou critérios mais detalhados, que incluíram: história e dados de exame físico para o diagnóstico de dermatite atópica, através de protocolos fotográficos pré-estabelecido. De um total de 271 crianças, 63 (23,2%) apresentavam história de lesão na pele sugestiva de dermatite atópica nos últimos 12 meses. Quando foi utilizado o critério UK com múltiplos dados de informação, mais exame físico, a prevalência da DA foi de 5,6%. Concluiu-se que a prevalência de DA pelo critério UK foi quatro vezes menor que a observada pela questão única sobre sintomas de dermatite atópica nos últimos 12 meses. A validade de dados de prevalência elevada de DA, definida somente por uma única pergunta em questionário, deve ser questionada a partir dos resultados do presente estudo.

[Upper airway cellular pattern in infants with acute bronchiolitis: neutrophils or eosinophils?]. / Padrão de celularidade nas vias aéreas superiores de lactentes com bronquiolite aguda: neutrófilos ou eosinófilos?

OBJECTIVE: To analyze the cellular pattern of nasopharyngeal secretions in infants with acute bronchiolitis (AB), focusing on the presence or absence of neutrophils and eosinophils. METHOD: Hospitalized children with AB admitted to Hospital São Lucas, Porto Alegre, Brazil, between May and July 2002 were recruited. Nasopharyngeal aspirates were collected during the first 48 hours after admission. Slides were stained with May Grunwald and Giemsa. Total cell count and cellular viability were obtained in all samples. RESULTS: Thirty-eight infants with AB were enrolled. The mean age was 2.2 months (interquartile range: 1.2-3.5), and 21 subjects were male. Neutrophils were the predominant cells in the nasopharyngeal aspirates (median 95%, interquartile: 94-97). No eosinophils were found in the samples studied. CONCLUSION: Our results suggest that eosinophils do not play a significant role in the pathophysiogenesis of AB. Infants with AB present a specific inflammatory response to viral infections, which is distinct from the immune response observed in asthma.

Padräo de celularidade nas vias aéreas superiores de lactentes com bronquiolite aguda: neutrófilos ou eosinófilos? / Upper airway cellular pattern in infants with acute bronchiolitis: neutrophils or eosinophils?

OBJETIVO: O objetivo deste estudo é analisar o exame citológico do aspirado nasofaríngeo de lactentes com bronquiolite aguda, especificamente em relaçäo à presença de neutrófilos e eosinófilos MÉTODOS: Foram recrutados lactentes hospitalizados com diagnóstico de bronquiolite aguda, no Hospital Säo Lucas da PUCRS, no período entre maio e julho de 2002. O aspirado nasofaríngeo foi coletado nas primeiras 48 horas de internaçäo hospitalar. O exame citológico diferencial foi realizado com coloraçäo de May Grunwald Giemsa. Foram realizadas também contagem total de células e viabilidade celular nas amostras estudadas. RESULTADOS: Foram selecionados 38 lactentes com bronquiolite aguda. A idade mediana foi de 2,2 meses (interquartil: 1,2-3,5), sendo 21 pacientes do sexo masculino. O exame citológico diferencial demonstrou um predomínio absoluto de neutrófilos, com mediana de 95 por cento (interquartil: 94-97). Näo foi detectada a presença de eosinófilos nas amostras estudadas. CONCLUSÖES: O aspirado nasofaríngeo de lactentes hospitalizados com bronquiolite aguda apresenta um predomínio absoluto de neutrófilos. Näo foram encontrados eosinófilos nessas amostras. Esses achados demonstram que lactentes com bronquiolite aguda apresentam uma resposta inflamatória neutrofílica, nas vias aéreas, aos vírus respiratórios, distinta daquela eosinofílica, encontrada em quadros de asma