Global disease burden of and risk factors for acute lower respiratory infections caused by respiratory syncytial virus in preterm infants and young children in 2019: a systematic review and meta-analysis of aggregated and individual participant data

BACKGROUND

Infants and young children born prematurely are at high risk of severe acute lower respiratory infection (ALRI) caused by respiratory syncytial virus (RSV). In this study, we aimed to assess the global disease burden of and risk factors for RSV-associated ALRI in infants and young children born before 37 weeks of gestation.

METHODS

We conducted a systematic review and meta-analysis of aggregated data from studies published between Jan 1, 1995, and Dec 31, 2021, identified from MEDLINE, Embase, and Global Health, and individual participant data shared by the Respiratory Virus Global Epidemiology Network on respiratory infectious diseases. We estimated RSV-associated ALRI incidence in community, hospital admission, in-hospital mortality, and overall mortality among children younger than 2 years born prematurely. We conducted two-stage random-effects meta-regression analyses accounting for chronological age groups, gestational age bands (early preterm, <32 weeks gestational age [wGA], and late preterm, 32 to <37 wGA), and changes over 5-year intervals from 2000 to 2019. Using individual participant data, we assessed perinatal, sociodemographic, and household factors, and underlying medical conditions for RSV-associated ALRI incidence, hospital admission, and three severity outcome groups (longer hospital stay [>4 days], use of supplemental oxygen and mechanical ventilation, or intensive care unit admission) by estimating pooled odds ratios (ORs) through a two-stage meta-analysis (multivariate logistic regression and random-effects meta-analysis). This study is registered with PROSPERO, CRD42021269742.

FINDINGS

We included 47 studies from the literature and 17 studies with individual participant-level data contributed by the participating investigators. We estimated that, in 2019, 1 650 000 (95% uncertainty range [UR] 1 350 000-1 990 000) RSV-associated ALRI episodes, 533 000 (385 000-730 000) RSV-associated hospital admissions, 3050 (1080-8620) RSV-associated in-hospital deaths, and 26 760 (11 190-46 240) RSV-attributable deaths occurred in preterm infants worldwide. Among early preterm infants, the RSV-associated ALRI incidence rate and hospitalisation rate were significantly higher (rate ratio [RR] ranging from 1·69 to 3·87 across different age groups and outcomes) than for all infants born at any gestational age. In the second year of life, early preterm infants and young children had a similar incidence rate but still a significantly higher hospitalisation rate (RR 2·26 [95% UR 1·27-3·98]) compared with all infants and young children. Although late preterm infants had RSV-associated ALRI incidence rates similar to that of all infants younger than 1 year, they had higher RSV-associated ALRI hospitalisation rate in the first 6 months (RR 1·93 [1·11-3·26]). Overall, preterm infants accounted for 25% (95% UR 16-37) of RSV-associated ALRI hospitalisations in all infants of any gestational age. RSV-associated ALRI in-hospital case fatality ratio in preterm infants was similar to all infants. The factors identified to be associated with RSV-associated ALRI incidence were mainly perinatal and sociodemographic characteristics, and factors associated with severe outcomes from infection were mainly underlying medical conditions including congenital heart disease, tracheostomy, bronchopulmonary dysplasia, chronic lung disease, or Down syndrome (with ORs ranging from 1·40 to 4·23).

INTERPRETATION

Preterm infants face a disproportionately high burden of RSV-associated disease, accounting for 25% of RSV hospitalisation burden. Early preterm infants have a substantial RSV hospitalisation burden persisting into the second year of life. Preventive products for RSV can have a substantial public health impact by preventing RSV-associated ALRI and severe outcomes from infection in preterm infants.

FUNDING

EU Innovative Medicines Initiative Respiratory Syncytial Virus Consortium in Europe.

Obesity drives adipose-derived stem cells into a senescent and dysfunctional phenotype associated with P38MAPK/NF-KB axis

BACKGROUND

Adipose-derived stem cells (ADSC) are multipotent cells implicated in tissue homeostasis. Obesity represents a chronic inflammatory disease associated with metabolic dysfunction and age-related mechanisms, with progressive accumulation of senescent cells and compromised ADSC function. In this study, we aimed to explore mechanisms associated with the inflammatory environment present in obesity in modulating ADSC to a senescent phenotype. We evaluated phenotypic and functional alterations through 18 days of treatment. ADSC were cultivated with a conditioned medium supplemented with a pool of plasma from eutrophic individuals (PE, n = 15) or with obesity (PO, n = 14), and compared to the control.

RESULTS

Our results showed that PO-treated ADSC exhibited decreased proliferative capacity with G2/M cycle arrest and CDKN1A (p21WAF1/Cip1) up-regulation. We also observed increased senescence-associated β-galactosidase (SA-β-gal) activity, which was positively correlated with TRF1 protein expression. After 18 days, ADSC treated with PO showed augmented CDKN2A (p16INK4A) expression, which was accompanied by a cumulative nuclear enlargement. After 10 days, ADSC treated with PO showed an increase in NF-κB phosphorylation, while PE and PO showed an increase in p38MAPK activation. PE and PO treatment also induced an increase in senescence-associated secretory phenotype (SASP) cytokines IL-6 and IL-8. PO-treated cells exhibited decreased metabolic activity, reduced oxygen consumption related to basal respiration, increased mitochondrial depolarization and biomass, and mitochondrial network remodeling, with no superoxide overproduction. Finally, we observed an accumulation of lipid droplets in PO-treated ADSC, implying an adaptive cellular mechanism induced by the obesogenic stimuli.

CONCLUSIONS

Taken together, our data suggest that the inflammatory environment observed in obesity induces a senescent phenotype associated with p38MAPK/NF-κB axis, which stimulates and amplifies the SASP and is associated with impaired mitochondrial homeostasis.

A biomarker assay to risk-stratify patients with symptoms of respiratory tract infection

BACKGROUND

Patients who present to an emergency department (ED) with respiratory symptoms are often conservatively triaged in favour of hospitalisation. We sought to determine if an inflammatory biomarker panel that identifies the host response better predicts hospitalisation in order to improve the precision of clinical decision making in the ED.

METHODS

From April 2020 to March 2021, plasma samples of 641 patients with symptoms of respiratory illness were collected from EDs in an international multicentre study: Canada (n=310), Italy (n=131) and Brazil (n=200). Patients were followed prospectively for 28 days. Subgroup analysis was conducted on confirmed coronavirus disease 2019 (COVID-19) patients (n=245). An inflammatory profile was determined using a rapid, 50-min, biomarker panel (RALI-Dx (Rapid Acute Lung Injury Diagnostic)), which measures interleukin (IL)-6, IL-8, IL-10, soluble tumour necrosis factor receptor 1 (sTNFR1) and soluble triggering receptor expressed on myeloid cells 1 (sTREM1).

RESULTS

RALI-Dx biomarkers were significantly elevated in patients who required hospitalisation across all three sites. A machine learning algorithm that was applied to predict hospitalisation using RALI-Dx biomarkers had a mean±sd area under the receiver operating characteristic curve of 76±6% (Canada), 84±4% (Italy) and 86±3% (Brazil). Model performance was 82±3% for COVID-19 patients and 87±7% for patients with a confirmed pneumonia diagnosis.

CONCLUSIONS

The rapid diagnostic biomarker panel accurately identified the need for inpatient care in patients presenting with respiratory symptoms, including COVID-19. The RALI-Dx test is broadly and easily applicable across many jurisdictions, and represents an important diagnostic adjunct to advance ED decision-making protocols.

Multi-vendor multi-site quantitative MRI analysis of cartilage degeneration 10 Years after anterior cruciate ligament reconstruction: MOON-MRI protocol and preliminary results

OBJECTIVE

To describe the protocol of a multi-vendor, multi-site quantitative MRI study for knee post-traumatic osteoarthritis (PTOA), and to present preliminary results of cartilage degeneration using MR T1ρ and T2 imaging 10 years after anterior cruciate ligament reconstruction (ACLR).

DESIGN

This study involves three sites and two MR platforms. The patients are from a nested cohort (termed as Onsite cohort) within the Multicenter Orthopaedic Outcomes Network (MOON) cohort 10 years after ACLR. Phantoms and controls were scanned for evaluating reproducibility. Cartilage was automatically segmented, and T1ρ and T2 were compared between operated, contralateral, and control knees.

RESULTS

Sixty-eight ACL-reconstructed patients and 20 healthy controls were included. In phantoms, the intra-site coefficients of variation (CVs) of repeated scans ranged 1.8-2.1% for T1ρ and 1.3-1.7% for T2. The inter-site CVs ranged 1.6-2.1% for T1ρ and 1.1-1.4% for T2. In human subjects, the intra-site scan/rescan CVs ranged 2.2-3.5% for T1ρ and 2.6-4.9% for T2 for the six major compartments. In patients, operated knees showed significantly higher T1ρ and T2 values mainly in medial femoral condyle, medial tibia and trochlear cartilage compared with contralateral knees, and showed significantly higer T1ρ and T2 values in all six compartments compared to healthy control knees. The patient contralateral knees showed higher T1ρ and T2 values mainly in the lateral femoral condyle, lateral tibia, trochlear, and patellar cartilage compared to healthy control knees.

CONCLUSION

A platform and workflow with rigorous quality control has been established for a multi-vendor multi-site quantitative MRI study in evaluating PTOA 10 years after ACLR. Our preliminary report suggests significant cartilage matrix changes in both operated and contralateral knees compared with healthy control knees.

Outpatient Respiratory Management of Infants, Children, and Adolescents with Post-Prematurity Respiratory Disease: An Official American Thoracic Society Clinical Practice Guideline

Background: Premature birth affects millions of neonates each year, placing them at risk for respiratory disease due to prematurity. Bronchopulmonary dysplasia is the most common chronic lung disease of infancy, but recent data suggest that even premature infants who do not meet the strict definition of bronchopulmonary dysplasia can develop adverse pulmonary outcomes later in life. This post-prematurity respiratory disease (PPRD) manifests as chronic respiratory symptoms, including cough, recurrent wheezing, exercise limitation, and reduced pulmonary function. This document provides an evidence-based clinical practice guideline on the outpatient management of infants, children, and adolescents with PPRD. Methods: A multidisciplinary panel of experts posed questions regarding the outpatient management of PPRD. We conducted a systematic review of the relevant literature. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate the quality of evidence and the strength of the clinical recommendations. Results: The panel members considered the strength of each recommendation and evaluated the benefits and risks of applying the intervention. In formulating the recommendations, the panel considered patient and caregiver values, the cost of care, and feasibility. Recommendations were developed for or against three common medical therapies and four diagnostic evaluations in the context of the outpatient management of PPRD. Conclusions: The panel developed recommendations for the outpatient management of patients with PPRD on the basis of limited evidence and expert opinion. Important areas for future research were identified.

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.

Nonspecific immunomodulators for recurrent respiratory tract infections, wheezing and asthma in children: a systematic review of mechanistic and clinical evidence

PURPOSE OF REVIEW

To provide an overview of the mechanistic and clinical evidence for the use of nonspecific immunomodulators in paediatric respiratory tract infection (RTI) and wheezing/asthma prophylaxis.

RECENT FINDINGS

Nonspecific immunomodulators have a long history of empirical use for the prevention of RTIs in vulnerable populations, such as children. The past decade has seen an increase in both the number and quality of studies providing mechanistic and clinical evidence for the prophylactic potential of nonspecific immunomodulators against both respiratory infections and wheezing/asthma in the paediatric population. Orally administered immunomodulators result in the mounting of innate and adaptive immune responses to infection in the respiratory mucosa and anti-inflammatory effects in proinflammatory environments. Clinical data reflect these mechanistic effects in reductions in the recurrence of respiratory infections and wheezing events in high-risk paediatric populations. A new generation of clinical studies is currently underway with the power to position the nonspecific bacterial lysate immunomodulator OM-85 as a potential antiasthma prophylactic.

SUMMARY

An established mechanistic and clinical role for prophylaxis against paediatric respiratory infections by nonspecific immunomodulators exists. Clinical trials underway promise to provide high-quality data to establish whether a similar role exists in wheezing/asthma prevention.

Impact of omalizumab in children from a middle-income country with severe therapy-resistant asthma: A real-life study

BACKGROUND

Severe asthma in children is a global health problem. Severe therapy-resistant asthma (STRA) in children is a major clinical challenge due to persistent symptoms despite high doses of corticosteroids and results in high public health costs. Omalizumab (anti-IgE monoclonal antibody) has been described as an effective add-on therapy in these patients. The characteristics of children with STRA from low- and middle-income countries have scarcely been reported, and no real-life study has been published on the effects of omalizumab in this group of patients. The aim of our study is to report the first clinical real-life experiences with omalizumab in Brazilian children with STRA.

METHODS

Children (6-18 years old) from a referral center who were diagnosed with STRA were included in this retrospective study based on our clinical databases. The included children had undergone at least 6 months of omalizumab treatment and fulfilled the following initial criteria: 1) >6 years old; 2) a positive skin-prick test for at least one aeroallergen; and 3) a serum total IgE level between 30 and 1500 IU/mL. Clinical and lung function variables were analyzed before and after treatment.

RESULTS

Fourteen children (mean age: 11.9 years; percentage female: 72%) were included in this study. Omalizumab treatment significantly increased control of the disease according to a standardized questionnaire administered at every visit (P < 0.0001), ceased hospitalizations in 70% (P = 0.02) of patients, and allowed 8/9 (89%) patients to be weaned off oral steroids (P = 0.004).

CONCLUSIONS

In this retrospective report, the use of omalizumab in Brazilian children with STRA significantly improved disease control, decreased hospitalizations, and allowed suspension of continuous oral corticosteroids.

Asthma and Obesity in Children Are Independently Associated with Airway Dysanapsis

BACKGROUND

An increase in the prevalence of overweight and asthma has been observed. Both conditions affect negatively lung function in adults and children. The aim of this study was to analyze the effect of overweight and asthma on lung function in children.

METHODS

We designed a case-control study of healthy and asthmatic subjects nested within an epidemiological asthma prevalence study in children between 8 and 16 years of age. The effect of asthma and overweight on lung function was assessed by impulse oscillometry and spirometry obtained at baseline and 10-15 min after salbutamol.

RESULTS

188 children were recruited, 114 (61%) were asthmatics and 72 (38%) were overweight or obese. Children with asthma and overweight had a higher FVC (+1.16 z scores, p < 0.001) and higher FEV₁ (+0.79 z scores, p = 0.004) and lower FEV₁/FVC (-0.54 z scores, p = 0.008) when compared to healthy controls. Compared to normal weight asthmatics, the overweight had higher FVC (+0.78 z scores, p = 0.005) and lower FEV₁/FVC (-0.50 z scores, p = 0.007). In the multivariate analysis, overweight was associated with an increase of 0.71 and 0.44 z scores in FVC and FEV₁, respectively, and a reduction in FEV₁/FVC by 0.40 z scores (p < 0.01 for all). Overweight had no effect on maximal flows and airway resistance at baseline, and this was not modified by inhalation of a bronchodilator. Asthma was also associated with higher post-BD FVC (0.45 z scores, p = 0.012) and FEV₁ (0.35 z scores, p = 0.034) but not with FEV₁/FVC and FEF_25-75%. Two-way analysis of variance did not detect any interaction between asthma and overweight on lung function variables before or after bronchodilator.

CONCLUSION

Our results suggest that asthma and overweight are independently associated with airway dysanaptic growth in children which can be further scrutinized using impulse oscillometry. Overweight contributed more to the reduction in FEV₁/FVC than asthma in children without increasing airway resistance. Spirometry specificity and sensitivity for obstructive diseases may be reduced in populations with high prevalence of overweight. Adding impedance oscillometry to spirometry improves our understanding of the ventilatory abnormalities in overweight children.

Bacterial extract (OM-85) with human-equivalent doses does not inhibit the development of asthma in a murine model

BACKGROUND

OM-85 is an immunostimulant bacterial lysate, which has been proven effective in reducing the number of lower airways infections. We investigated the efficacy of the bacterial lysate OM-85 in the primary prevention of a murine model of asthma.

METHODS

In the first phase of our study the animals received doses of 0.5μg, 5μg and 50μg of OM-85 through gavage for five days (days -10 to -6 of the protocol), 10 days prior to starting the sensitisation with ovalbumin (OVA), in order to evaluate the results of dose-response protocols. A single dose (5μg) was then chosen in order to verify in detail the effect of OM-85 on the pulmonary allergic response. Total/differential cells count and cytokine levels (IL-4, IL-5, IL-13 and IFN-γ) from bronchoalveolar lavage fluid (BALF), OVA-specific IgE levels from serum, lung function and lung histopathological analysis were evaluated.

RESULTS

OM-85 did not reduce pulmonary eosinophilic response, regardless of the dose used. In the phase protocol using 5μg/animal of OM-85, no difference was shown among the groups studied, including total cell and eosinophil counts in BALF, serum OVA-specific IgE, lung histopathologic findings and lung resistance. However, OM-85 decreased IL-5 and IL-13 levels in BALF.

CONCLUSIONS

OM-85, administered in early life in mice in human-equivalent doses, does not inhibit the development of allergic pulmonary response in mice.

SINEUPs: A new class of natural and synthetic antisense long non-coding RNAs that activate translation

Over the past 10 years, it has emerged that pervasive transcription in mammalian genomes has a tremendous impact on several biological functions. Most of transcribed RNAs are lncRNAs and repetitive elements. In this review, we will detail the discovery of a new functional class of natural and synthetic antisense lncRNAs that stimulate translation of sense mRNAs. These molecules have been named SINEUPs since their function requires the activity of an embedded inverted SINEB2 sequence to UP-regulate translation. Natural SINEUPs suggest that embedded Transposable Elements may represent functional domains in long non-coding RNAs. Synthetic SINEUPs may be designed by targeting the antisense sequence to the mRNA of choice representing the first scalable tool to increase protein synthesis of potentially any gene of interest. We will discuss potential applications of SINEUP technology in the field of molecular biology experiments, in protein manufacturing as well as in therapy of haploinsufficiencies.

Effect of different helminth extracts on the development of asthma in mice: The influence of early-life exposure and the role of IL-10 response

It is not currently clear whether different parasites have distinct effects on the airway inflammatory response in asthma and whether exposure in early life to helminths have a stronger impact in a potential inhibitory effect on asthma. The aim of this study is to evaluate the effect of exposure to different helminth extracts on the development of allergic pulmonary response in mice, including early-life exposure. Different helminth extracts (Angiostrongylus costaricensis, Angiostrongylus cantonensis and Ascaris lumbricoides) were studied in female adult BALB/c and C57BL/6 IL-10-deficient mice in a protocol of murine asthma, injected intraperitoneally in different periods of exposure (early, pre-sensitization and post-sensitization). Cell counts in bronchoalveolar lavage (BAL), eosinophil peroxidase (EPO) from lung tissue, cytokine levels from BAL/spleen cell cultures, and lung histology were analyzed. Airway cellular influx induced by OVA was significantly inhibited by extracts of A. cantonensis and A. lumbricoides. Extracts of A. lumbricoides and A. costaricensis led to a significant reduction of IL-5 in BAL (p < 0.001). Only the exposure to A. lumbricoides led to an increased production of IL-10 in the lungs (p < 0.001). In IL-10-deficient mice exposed to A. costaricensis pre-sensitization, eosinophil counts and IL-5 levels in BAL and EPO in lung tissue were significantly reduced. In the early exposure to A. cantonensis, lung inflammation was clearly inhibited. In conclusion, different helminth extracts inhibit allergic lung inflammation in mice. IL-10 may not play a central role in some helminth-host interactions. Early exposure to helminth extracts could be a potential strategy to explore primary prevention 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.

Imaging of a circumsolar dust ring near the orbit of Venus

The gravitational interaction of dust in the zodiacal cloud with individual planets is expected to give rise to ringlike features: Such a circumsolar ring has been observed associated with Earth, but such resonance rings have not been confirmed to exist for other planets. Here, we report on sensitive photometric observations, based on imaging from the STEREO mission, that confirm the existence of a dust ring at the orbit of Venus. The maximum overdensity of dust in this ring, compared to the zodiacal cloud, is ~10%. The radial density profile of this ring differs from the model used to describe Earth's ring in that it has two distinct steplike components, with one step being interior and the other exterior to the orbit of Venus.

Radiographic joint space width is correlated with 4-year clinical outcomes in patients with knee osteoarthritis: data from the osteoarthritis initiative

OBJECTIVE

To evaluate if quantitative joint space width (JSW) measurements from radiographs correlate with 4-year Knee injury and Osteoarthritis Outcome Scores (KOOS) and clinical performance measures.

METHOD

The study group consisted of 942 patients with symptomatic knee osteoarthritis (OA). 4-year outcomes for six measures (KOOS Pain, Symptom, Quality of Life, and Function scores, 20-m walk pace, and chair stand time) were used to create six multiple linear regression models. Primary predictors were baseline minimum JSW and 4-year change in JSW measured from fixed flexion radiographs. Age, gender, body mass index (BMI), race, knee alignment, and baseline measures of the outcomes of interest were covariates.

RESULTS

Lower baseline minimum JSW and a greater decrease in 4-year JSW significantly correlated with worse 4-year KOOS Pain, Symptom, and Quality of Life. With all other factors constant, a 4.1, 4.8, and 5.6 mm lower baseline JSW correlated with a clinically significant eight-point drop in 4-year KOOS Pain, Symptom, and Quality of Life scores respectively. Additionally, a 3.5, 3.1, and 4.0 mm loss of JSW over 4 years correlated with a clinically significant eight-point drop in 4-year KOOS Pain, Symptom, and Quality of Life scores respectively.

CONCLUSIONS

Our results indicate quantitative radiographic JSW measurements correlate with 4-year clinical outcomes. Since patients with narrower JSW at the onset of study had lower KOOS scores at 4 years even after controlling for 4-year change in JSW and baseline KOOS scores, clinical outcomes in knee OA may be predetermined once the disease process begins. These findings suggest early treatment with disease modifying therapies may be necessary to influence outcomes.

Risk factors for need of mechanical ventilation in children with influenza A(H1N1)pdm09

OBJECTIVE

The pandemic caused by influenza A(H1N1)pdm09 virus peaked between July and August of 2009 in southern Brazil, with the highest incidence in children and young adults. In the post-pandemic period, there was an increase in the incidence of cases during the winter months of 2011 and 2012 in Brazil, similar to seasonal influenza virus. Since infections due to pandemic influenza are still occurring, the present study aimed to investigate the risk factors for worse outcome in children.

METHODS

A retrospective cohort study was performed by reviewing the charts of hospitalized patients younger than 14 years with reverse transcription-polymerase chain reaction (RT-PCR) positive for influenza A(H1N1)pdm09 during the first pandemic wave in six Brazilian tertiary centers. Need for mechanical ventilation was defined as the severity of outcome; age, chronic diseases, bacterial and viral co-detection, chest radiograph findings, and use of oseltamivir were possible predictors.

RESULTS

In the present study, 120 patients were included. In a multivariate analysis, chronic diseases (prevalence ratio: 2.613, 95% CI: 1.267-5.386) and viral co-detection (prevalence ratio: 2.43, 95% CI: 1.203-4.905) were statistically associated with worse outcome (p<0.05).

CONCLUSIONS

The presence of chronic diseases as predictors reinforces previous finding. Furthermore, viral co-detection was found to be a risk factor. Further studies are necessary to confirm this association.

Severe lower respiratory tract infection in infants and toddlers from a non-affluent population: viral etiology and co-detection as risk factors

BACKGROUND

Lower respiratory tract infection (LRTI) is a major cause of pediatric morbidity and mortality, especially among non-affluent communities. In this study we determine the impact of respiratory viruses and how viral co-detections/infections can affect clinical LRTI severity in children in a hospital setting.

METHODS

Patients younger than 3 years of age admitted to a tertiary hospital in Brazil during the months of high prevalence of respiratory viruses had samples collected from nasopharyngeal aspiration. These samples were tested for 13 different respiratory viruses through real-time PCR (rt-PCR). Patients were followed during hospitalization, and clinical data and population characteristics were collected during that period and at discharge to evaluate severity markers, especially length of hospital stay and oxygen use. Univariate regression analyses identified potential risk factors and multivariate logistic regressions were used to determine the impact of specific viral detections as well as viral co-detections in relation to clinical outcomes.

RESULTS

We analyzed 260 episodes of LRTI with a viral detection rate of 85% (n = 222). Co-detection was observed in 65% of all virus-positive episodes. The most prevalent virus was Respiratory Syncytial Virus (RSV) (54%), followed by Human Metapneumovirus (hMPV) (32%) and Human Rhinovirus (HRV) (21%). In the multivariate models, infants with co-detection of HRV + RSV stayed 4.5 extra days (p = 0.004), when compared to infants without the co-detection. The same trends were observed for the outcome of days of supplemental oxygen use.

CONCLUSIONS

Although RSV remains as the main cause of LRTI in infants our study indicates an increase in the length of hospital stay and oxygen use in infants with HRV detected by RT-PCR compared to those without HRV. Moreover, one can speculate that when HRV is detected simultaneously with RSV there is an additive effect that may be reflected in more severe clinical outcome. Also, our study identified a significant number of children infected by recently identified viruses, such as hMPV and Human Bocavirus (HBov), and this is a novel finding for poor communities from developing countries.

Azithromycin therapy in hospitalized infants with acute bronchiolitis is not associated with better clinical outcomes: a randomized, double-blinded, and placebo-controlled clinical trial

OBJECTIVE

To test the hypothesis that azithromycin reduces the length of hospitalization and oxygen requirement in infants with acute viral bronchiolitis (AB).

STUDY DESIGN

We performed a randomized, double-blinded, placebo-controlled trial in southern Brazil, from 2009 to 2011. Infants (<12 months of age) hospitalized with AB were recruited in 2 hospitals. Patients were randomized to receive either azithromycin or placebo, administered orally, for 7 days. At enrollment, clinical data were recorded and nasopharyngeal samples were collected for viral identification through immunofluorescence. Main outcomes were duration of oxygen requirement and length of hospitalization.

RESULTS

One hundred eighty-four patients were included in the study (azithromycin 88 subjects, placebo 96 subjects). Baseline clinical characteristics and viral identification were not different between the groups studied. A virus was detected in 112 (63%) patients, and of those, 92% were positive for respiratory syncytial virus. The use of azithromycin did not reduce the median number of days of either hospitalization (P = .28) or oxygen requirement (P = .47).

CONCLUSIONS

Azithromycin did not improve major clinical outcomes in a large sample of hospitalized infants with AB, even when restricting the findings to those with positive respiratory syncytial virus samples. Azithromycin therapy should not be given for AB because it provides no benefit and overuse increases overall antibiotic resistance.

Cost-effectiveness of ultrasound use by on-call registrars in an acute gynaecology setting

Ultrasound, and in particular transvaginal sonography (TVS), plays an important role in the management of women with acute gynaecology conditions. This study compared the cost-effectiveness of two models of out-of-hours care for women in an acute gynaecology setting. In the ultrasound-based model, the on-call registrar with ultrasound experience managed such patients after performing pelvic ultrasound as a part of the initial assessment. On the other hand, in the traditional model of care the on-call registrar managed the patients without the use of ultrasound. The conclusion is that the use of ultrasound by the on-call registrars has significant cost implications through reduced hospital admissions. It leads to improved outcomes of such patients through timely diagnosis and treatment.

Revision ACL reconstruction outcomes: MOON cohort

Many clinicians believe that the results of revision anterior cruciate ligament (ACL) reconstruction compare unfavorably with primary ACL reconstruction. However, few prospective studies have evaluated revision ACL reconstruction using validated patient-based metrics. This study was performed to evaluate and compare the results of revision ACL reconstruction and primary ACL reconstruction. The Multicenter Orthopaedic Outcomes Network consortium is an NIH-funded, hypothesis-driven, multicenter prospective cohort study of patients undergoing ACL reconstruction. All patients preoperatively complete a series of validated patient-oriented questionnaires. At scheduled 2-year follow-up all patients are given the same series of questionnaires to complete. The study evaluated the results of 2-year follow-up of revision ACL reconstruction performed in 2001. Parameters evaluated included Marx activity level, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) scores. For this study 446 subjects met inclusion criteria; 2-year follow-up was obtained on 393 (88%). The study group consisted of 55% males with median age of 22 years. There were 33 revision ACL reconstruction cases, for which follow-up was available for 29 (88%). Median baseline Marx (interquartile range) was 12 (8 to 16) and 12 (6 to 16) for the primary ACL reconstruction and revision ACL reconstruction groups, respectively (p= 0.81). At 2 years, median Marx was 9 (4 to 13) and 5 (0 to 10) for the primary ACL reconstruction and revision ACL reconstruction groups, respectively (p= 0.03). Median 2-year IKDC was 75.9 (revision) versus 83.9 (primary) (p=0.003). Median KOOS subscale Knee Related Quality of Life (KRQOL) at 2 years was 62.5 (revision) versus 75 (primary) (p < 0.001), subscale Sports and Recreation was 75 (revision) and 85 (primary) (p = 0.005), subscale Pain was 83.3 (revision) and 91.7 (primary) (p= 0.002). Marx activity score declined at 2-year follow-up in revision ACL reconstruction compared with primary ACL reconstruction. IKDC and KRQOL were significantly decreased in revision ACL reconstruction compared with primary ACL reconstruction at 2-year followup. Revision ACL reconstruction resulted in a significantly worse outcome as measured by these patient-based measures at 2 years.

Peripheral glucocorticoid sensitivity in children with controlled persistent asthma

BACKGROUND

Persistent asthma in children is a chronic inflammatory disease and glucocorticoids (GCs) are currently recognized as the mainstay of therapy. Clinical and in vitro steroid resistance has been demonstrated in severe asthma. However, GC insensitivity has not been studied in children with controlled persistent asthma.

OBJECTIVES

To analyze peripheral blood mononuclear cell (PBMC) sensitivity to GC in children (6-15 years) with persistent asthma and healthy controls.

METHODS

Children with persistent asthma were selected and lung function and skin-prick tests were performed in all studied asthmatic children. PBMCs were isolated and cultured in vitro to assess mitogen-induced proliferation and cellular sensitivity to dexamethasone.

RESULTS

Fifty-seven children with persistent and controlled asthma (mean age 10 years) were recruited and divided into 3 groups (severe, moderate and mild), and compared to healthy children (n = 18). Children with asthma, regardless of the severity of disease, presented similar sensitivity to GCs when compared to healthy children. Patients with mild asthma showed significantly less sensitivity to dexamethasone and children with severe asthma had similar sensitivity to dexamethasone when compared to controls.

CONCLUSIONS

In vitro insensitivity to GCs was not demonstrated in children with controlled persistent asthma, even in those with severe disease. Our findings suggest that resistance to GCs in older patients with severe asthma might be an acquired process. However, future longitudinal studies are necessary to confirm this hypothesis.

Plasma brain-derived neurotrophic factor levels are associated with clinical severity in school age children with asthma

BACKGROUND

Asthma is characterized by chronic inflammation of the airways with significant changes in leucocyte trafficking, cellular activation and tissue remodelling. Brain-derived neurotrophic factor (BDNF) has been involved with asthma and allergic diseases but its role as a severity marker in paediatric asthma has not been clinically assessed.

OBJECTIVES

To evaluate plasma BDNF and inflammatory markers in order to address their relationships with disease severity in children (6-15 years) with controlled persistent asthma.

METHODS

Children with persistent asthma were selected and lung function and skin prick tests were performed in all patients. Plasma BDNF levels and various inflammatory markers (CCL3, CCL11, CCL22, CCL24, CXCL8, CXCL9, CXCL10, soluble TNF receptors) were assessed by ELISAs.

RESULTS

Subjects with moderate and severe asthma had higher BDNF levels than mild asthma and controls (P<0.001). The chemokines studied and soluble TNF receptors did not differ between the studied groups.

CONCLUSION AND CLINICAL RELEVANCE

Our results indicate BDNF as a potential biomarker for clinical severity in children with asthma.

Evaluation of airway reactivity and immune characteristics as risk factors for wheezing early in life

BACKGROUND

Childhood asthma is most often characterized by recurrent wheezing, airway hyperreactivity, and atopy; however, our understanding of these relationships from early in life remains unclear. Respiratory tract illnesses and atopic sensitization early in life might produce an interaction between innate and acquired immune responses, leading to airway inflammation and heightened airway reactivity.

OBJECTIVE

We hypothesized that premorbid airway reactivity and immunologic characteristics of infants without prior episodes of wheezing would be associated with subsequent wheezing during a 1-year follow-up.

METHODS

One hundred sixteen infants with chronic dermatitis were enrolled before episodes of wheezing. Airway reactivity, allergen-specific IgE levels, cytokine production by stimulated PBMCs, and percentages of dendritic cells were measured on entry, and airway reactivity was reassessed at the 1-year follow-up. Linear regression models were used to evaluate a predictor's effect on continuous outcomes.

RESULTS

Milk sensitization, egg sensitization, or both were associated with heightened airway reactivity before wheezing and after the onset of wheezing; however, these factors were not associated with an increased risk of wheezing. There was an interaction between initial airway reactivity and wheezing as a determinant of airway reactivity at follow-up. In addition, cytokine production by stimulated PBMCs was a risk factor for wheezing, whereas increased percentages of conventional dendritic cells were protective against wheezing.

CONCLUSION

Our data in a selected cohort of infants support a model with multiple risk factors for subsequent wheezing that are independent of initial airway reactivity; however, the causative factors that produce wheezing very early in life might contribute to heightened airway reactivity.

Nutritional errors in the first months of life and their association with asthma and atopy in preschool children

OBJECTIVE

To evaluate the impact of exclusive breastfeeding and introduction of cow's milk in the first year of life on the diagnosis of asthma, wheezing, and atopy in children aged 3 to 4 years.

METHODS

This is a cohort study nested in a randomized field trial investigating the effectiveness of dietary guidelines during the first year of life of children in the city of São Leopoldo, southern Brazil. Children who had their diet monitored during the first year of life, in a primary study, were revisited three years later, when their parents answered a questionnaire related to respiratory problems, applied during home visits by trained interviewers. Children were also skin-prick tested to assess responses to common environmental allergens.

RESULTS

Of the 397 children followed during the first year of life, 354 were reassessed between 3 and 4 years of age. Prevalence of wheezing, evaluated for the 12 months prior to questionnaires, was 21.3%, while prevalence of asthma and atopy was 5.5 and 28.7%, respectively. Children fed cow's milk previous to being four months of life were significantly more likely to have asthma between three and four years of age (OR 3.22; 95%CI 1.05-9.80). In the same line, exclusive breastfeeding for a period shorter than six months was marginally associated with atopy.

CONCLUSIONS

The early introduction of cow's milk was an important risk factor for triggering asthma/wheeze symptoms at the age of 4 years. Exclusive breastfeeding for longer than six months was also potentially associated with protection against the development of atopy. The results of this study suggest that dietary interventions during the first year of life have the potential to reduce the impact of asthma, and possibly, atopy.

Expectant management of first-trimester miscarriage

Miscarriage is the most common complication of pregnancy, which creates a significant workload for health-care professionals. For decades, surgical evacuation of the uterus has remained the conventional treatment of first-trimester miscarriage. Recently, non surgical treatments have been introduced with increasing popularity. This review explores the evidence in support of expectant management of first-trimester miscarriage. It is safe, effective and well-tolerated by women. It enhances women's choice and control. It generates significant cost savings compared with the traditional surgical management. Accurate diagnosis, counselling, 24/7 telephone advice and follow-up are among the important aspects of expectant management. More studies are needed to develop methods for identifying miscarriages suitable for expectant management.

Neutrophilic airway inflammation is a main feature of induced sputum in nonatopic asthmatic children

BACKGROUND

Asthma phenotypes are well described among children. However, there are few studies comparing airway inflammation in different clinical presentations of pediatric asthma. We tested the hypothesis that nonatopic asthma is associated with a predominant noneosinophilic inflammation in the airways, as assessed by induced sputum. The objective of this study was to evaluate the cytological characteristics of induced sputum (IS) in atopic (AA), nonatopic asthmatics (NAA) and nonatopic nonasthmatic children (NANA).

METHODS

Of 90 selected children, 77 met eligibility criteria for performing IS and were classified as: AA, n = 28, NAA, n = 29 and NANA, n = 19. Subjects answered to a set of ISAAC-based questions and were skin-tested for common aeroallergens. A defined series of exclusion criteria was applied.

RESULTS

Induced sputum was obtained from 54 (70.1%) subjects (21 AA, 20 NAA and 13 NANA). Demographic data and mean FEV(1) were similar in the three groups. The proportion of eosinophils [median, inter quartile range (IQR)] was significantly higher in the sputum of AA [(6.0.)12)] compared with NAAs [0 (2)] and NANAs [0 (1)], P < 0.001. The proportion of children with sputum eosinophilia (eos > 3%) was also significantly higher in AA (71.4%) when compared with NAA (28.6%); none of the NANA had sputum eosinophilia. Nonatopic asthmatic children had significantly higher proportions and absolute number of neutrophils than AA and controls.

CONCLUSIONS

The results suggest that nonatopic children present IS with a cell pattern that is predominantly neutrophilic while eosinophilia is the hallmark of airway inflammation in the majority of atopic wheezing children not treated with inhaled steroids.

The 30 minutes decision-to-delivery interval for ‘urgent’ caesarean sections: An elusive target

The aim of this audit was to evaluate whether the '30 minute decision-to-delivery interval' for 'urgent' caesarean section has shown consistent improvement with repeated audit within this unit. The audit dataset comprised a random sample of all urgent caesarean sections carried out in 2004 classified as 'urgent', i.e. to be completed in 30 min. Nearly one-third of caesarean sections recorded on the delivery suite database as 'urgent' were incorrectly coded. A personal review of case notes was undertaken to ensure accurate data capture. Delivery suite data was analysed by post-hoc modelling of a 'normal' (Gaussian) distribution. The proportion of true 'urgent' caesarean sections completed in 30 min was 50% and some 90% of women were delivered within 40 min. The data were normally distributed, with non-random events, accounted for 25% of the variability. A model for 'urgent' caesarean section, accommodating random and non-random factors closely matched the audit data. We conclude that non-random, institutional, factors reflecting overall delivery suite activity adversely effect the decision-to-delivery interval regardless of the performance of personnel and processes within a delivery suite.

Growth of the lung parenchyma early in life

RATIONALE

Early in life, lung growth can occur by alveolarization, an increase in the number of alveoli, as well as expansion. We hypothesized that if lung growth early in life occurred primarily by alveolarization, then the ratio of pulmonary diffusion capacity of carbon monoxide (Dl(CO)) to alveolar volume (V(A)) would remain constant; however, if lung growth occurred primarily by alveolar expansion, then Dl(CO)/V(A) would decline with increasing age, as observed in older children and adolescents.

OBJECTIVES

To evaluate the relationship between alveolar volume and pulmonary diffusion capacity early in life.

METHODS

In 50 sleeping infants and toddlers, with equal number of males and females between the ages of 3 and 23 months, we measured Dl(CO) and V(A) using single breath-hold maneuvers at elevated lung volumes.

MEASUREMENTS AND MAIN RESULTS

Dl(CO) and V(A) increased with increasing age and body length. Males had higher Dl(CO) and V(A) when adjusted for age, but not when adjusted for length. Dl(CO) increased with V(A); there was no gender difference when Dl(CO) was adjusted for V(A). The ratio of Dl(CO)/V(A) remained constant with age and body length.

CONCLUSIONS

Our results suggest that surface area for diffusion increases proportionally with alveolar volume in the first 2 years of life. Larger Dl(CO) and V(A) for males than females when adjusted for age, but not when adjusted for length, is primarily related to greater body length in boys. The constant ratio for Dl(CO)/V(A) in infants and toddlers is consistent with lung growth in this age occurring primarily by the addition of alveoli rather than the expansion of alveoli.

Expired nitric oxide and airway reactivity in infants at risk for asthma

BACKGROUND

Family histories of atopy, as well as histories of atopic dermatitis and food allergy, are important risk factors for an infant to have asthma. Although atopic sensitization appears to contribute to the development of asthma, it is unclear when the airways become involved with the atopic process and whether airway function relates to the atopic characteristics of the infant.

OBJECTIVE

We sought to evaluate whether atopic infants without prior episodes of wheezing have increased expired nitric oxide (eNO) levels and heightened airway reactivity.

METHODS

Infants with eczema were recruited, and atopic status was defined by specific IgE levels to foods or aeroallergens and total IgE levels. eNO, forced expiratory flow at 75% exhaled volume (FEF(75)), and airway reactivity to inhaled methacholine were measured in sedated infants. Airway reactivity was quantified by using the provocative concentration to decrease FEF(75) by 30%.

RESULTS

Median age for the 114 infants evaluated was 10.7 months (range, 2.6-19.1 months). Infants sensitized to egg or milk compared with infants sensitized to neither egg nor milk had lower flows (FEF(75): 336 vs 285 mL/s, P < .003) and lower lnPC(30) (mg/mL) provocative concentrations to decrease FEF(75) by 30% (-0.6 vs -1.2, P < .02) but no difference in eNO levels. Infants with total serum IgE levels of greater than 20 IU/mL had higher eNO levels compared with infants with IgE levels of 20 IU/mL or less (14.6 vs 11.2 ppb, P < .023) but no difference in forced flows or airway reactivity.

CONCLUSIONS

Our findings suggest that atopic characteristics of the infant might be important determinants of the airway physiology of forced expiratory flows, airway reactivity, and eNO.

Intestinal helminth infestation is associated with increased bronchial responsiveness in children

Non-atopic asthma is the predominant phenotype in non-affluent parts of Latin America. We recently reported that infestation with Ascaris lumbricoides increased the risk of non-atopic asthma in less affluent areas of Brazil but the mechanism is unclear. The present study was conducted to determine whether helminth infestation is associated with heightened bronchial responsiveness (BHR), a common finding in asthma. A random sample of 50 asthmatic and 50 non-asthmatic controls (mean age 10.1 years) were selected from a larger cohort (n = 1,011) without knowledge of their helminth infestation status. Three stool samples were collected from each child on different days and each sample was analyzed by the Kato-Katz method for quantitative determination of helminth eggs. Bronchial provocation tests were performed with inhaled 4.5% hypertonic saline using the ISAAC Phase II standardized protocol. There was no difference between the prevalence of positive BHR in the asthmatics (20.4%) compared with the controls (14.6%) (P = 1.0). Helminth infestation was detected in 24.0% of children, with A. lumbricoides being the most common. Children with high load infestation (>or=100 eggs/g) were five times more likely to have BHR than children with low load or no infestation. Despite the small sample size the results of the present study suggest that the link between high load helminth infestation and non-atopic asthma may be mediated via heightened bronchial responsiveness, possibly due to an inflammatory response to the pulmonary phase of the helminth life cycle.

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.

TNF-a and IL-10 levels in tracheobronchial lavage of ventilated preterm infants and subsequent lung function

The role of airway inflammation in ventilated preterm newborns and the risk factors associated with the development of chronic lung disease are not well understood. Our objective was to analyze the association of the airway inflammatory response in ventilated preterm infants by serial measurements of TNF-alpha and IL-10 in tracheobronchial lavage (TBL) with perinatal factors and lung function measured early in life. A series of TBL samples were collected from ventilated preterm infants (less than 32 weeks of gestational age) and concentrations of TNF-alpha and IL-10 were measured by ELISA. Pulmonary function tests were performed after discharge by the raised volume rapid compression technique. Twenty-five subjects were recruited and 70 TBL samples were obtained. There was a significant positive association between TNF-alpha and IL-10 levels and length of time between the rupture of the amniotic membranes and delivery (r = 0.65, P = 0.002, and r = 0.57, P < 0.001, respectively). Lung function was measured between 1 and 22 weeks of corrected age in 10 patients. Multivariable analysis with adjustment for differences in lung volume showed a significant negative association between TNF-alpha levels and forced expiratory flow (FEF(50); r = -0.6; P = 0.04), FEF(75) (r = -0.76; P = 0.02), FEF(85) (r = -0.75; P = 0.03), FEF(25-75) (-0.71; P = 0.02), and FEV(0.5) (r = -0.39; P = 0.03). These data suggest that TNF-alpha levels in the airways during the first days of life were associated with subsequent lung function abnormalities measured weeks or months later.

Nonatopic asthma is associated with helminth infections and bronchiolitis in poor children

Asthma is common in urban centres in Latin America, but atopic asthma may not be the main phenotype among children. Helminth infections are highly prevalent in poor populations, and it was hypothesised that they attenuate allergic asthma, whereas other factors are related to the expression of a nonatopic wheeze/asthma phenotype. A total of 1,982 children from Southern Brazil with a mean+/-sd age of 10.1+/-0.76 yrs completed asthma questionnaires, and 1,011 were evaluated for intestinal parasites and atopy using skin-prick tests (SPTs). Wheeze in the previous 12 months was reported by 25.6%, and 9.3% showed current asthma; 13% were SPT-positive and 19.1% were positive for any helminths. Most children with either wheeze or asthma were SPT-negative; however, severe wheeze was more prevalent among the atopic minority. Helminth infections were inversely associated with positive SPT results. Bronchiolitis before the age of 2 yrs was the major independent risk factor for asthma at age 10 yrs; high-load Ascaris infection, a family history of asthma and positive SPT results were also asthma risk factors. Most asthma and wheeze are of the nonatopic phenotype, suggesting that some helminths may exert an attenuating effect on the expression of the atopic portion of the disease, whereas viral bronchiolitis predisposes more specifically to recurrent airway symptoms.

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.

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.

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.

[Plastic bronchitis in a child with thalassemia alpha]

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.

[Rhinovirus and acute bronchiolitis in young infants]

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.

[Pulmonary prognosis in preterm infants]

OBJECTIVE

The increased survival of preterm infants poses the challenge of dealing with a wide range of chronic pulmonary diseases, including bronchopulmonary dysplasia, Wilson-Mikity syndrome and recurrent wheezing. This article reviews the pulmonary clinical and functional prognosis of preterm newborns in infancy and adolescence.

SOURCE OF DATA

MEDLINE search for articles published between 1970 and 2004 that focused on lung growth and function of preterm infants, besides a clinical follow-up of this group.

SUMMARY OF THE FINDINGS

Prenatal and postnatal events, such as placental insufficiency, tobacco exposure, infections, oxygen and mechanical ventilation, have an important effect on lung development and can lead to chronic lung diseases, of which bronchopulmonary dysplasia is the most severe complication. However, significant loss of lung function occurs in preterm infants who do not fulfill the criteria for bronchopulmonary dysplasia, and even in those who did not have significant respiratory disease during the neonatal period. The impact of prematurity on the respiratory system of these patients is usually underestimated. Clinically, preterm infants have an increased incidence of pneumonia and bronchiolitis, hospital readmissions due to respiratory diseases, chronic cough and wheezing and bronchial hyperresponsiveness. In adolescence, there is a tendency for normalization of the lung function, but they persist with reduced flows, lower exercise tolerance and bronchial hyperresponsiveness.

CONCLUSIONS

Prematurity, the events that cause it and the interventions that follow it permanently change the development of the respiratory system. Studies are necessary to clarify the effect of each of these perinatal insults on the development of the respiratory system.

Th-1 and Th-2 cytokine production in infants with virus-associated wheezing

Wheezing associated with respiratory viral infections in infancy is very common and results in high morbidity worldwide. The Th1/Th2 pattern of immune response in these patients remains unclear and previous studies have shown controversial results. The aim of the present study was to compare the type of Th1/Th2 cytokine response between infants with acute bronchiolitis, recurrent wheezing and upper respiratory infections from a developing country. Infants younger than 2 years of age admitted to Hospital São Lucas, Porto Alegre, RS, Brazil, between May and November 2001, with an acute episode of wheezing associated with viral respiratory infection were selected. Subjects with upper respiratory infections from the emergency department were selected for the control group. Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) levels from nasal aspirates were determined by ELISA from peripheral mononuclear cell cultures. Twenty-nine subjects with acute bronchiolitis, 18 with recurrent wheezing and 15 with upper respiratory infections were enrolled. There were no differences in family history of atopy or parental smoking between groups. Oxygen requirement was similar for the acute bronchiolitis and recurrent wheezing groups. The percentage of positive tests for the cytokines studied and the IFN-gamma/IL-4 ratio was similar for all groups. Comparison of the polarized Th1/Th2 cytokine results for the various groups showed no specific pattern of cytokine production. Infants with wheezing from a developing country do not show any specific predominant pattern of Th1/Th2 cytokine production, suggesting that multiple factors may be involved in the pathogenesis of this illness.

Infection of BALB/c mice with Angiostrongylus costaricensis decreases pulmonary inflammatory response to ovalbumin

SUMMARY The prevalence of asthma in developing countries is lower than in developed countries. Viral, bacterial and parasitic infections may be associated with this discrepancy. The relationship between parasitic infection and asthma prevalence is not clear. Previous controversial data have demonstrated that parasitic infection may either predispose or protect against the development of asthma. The aim of this study is to determine whether infection with Angiostrongylus costaricensis (A. costaricensis) decreases inflammatory lung response to ovalbumin (OVA) in mice. Seven BALB/c mice were infected with A. costaricensis by orogastric gavage (10 larvae/mouse) on day (D) 0. The mice were immunized against OVA by intraperitoneal injection on D 5 and D 12 and received an intranasal OVA challenge (40 micro L) on D 15 and D 17. On D 19 bronchoalveolar lavage (BAL) was performed. Six BALB/c mice (control group) were immunized with OVA using the same protocol, but were not infected with A. costaricensis. Interleukin (IL)-1beta and IL-6 levels were measured in the BAL fluid by using commercial ELISA assays. Total cell counts and differential cell counts were performed in the BAL fluid samples. The group infected with A. costaricensis had lower total cell count in the BAL fluid when compared with the control group (0.11 x 10(6)cells/mL and 0.3 x 10(6)cells/mL, respectively; P = 0.013). BAL fluid IL-1beta levels in the infected group were significantly lower than in the control group (P = 0.008). IL-6 levels in BAL fluid were not different between the groups studied. We conclude that Angiostrongylus costaricensis infection in mice decreases pulmonary inflammatory response to OVA.