Publications by authors named "Allen Julian"

Importance: Objective measures of lung function are critical for assessing respiratory outcomes of prematurity. Among extremely low gestational age neonates (ELGANs) (< 29 weeks gestational age), high rates of neurodevelopmental impairment may interfere with lung function testing. Impulse oscillometry (IOS) is a noninvasive test of respiratory system mechanics not requiring forced expiration.

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Rationale: Cardiopulmonary dysfunction is a major contributor to mortality among persons with sickle cell disease (pwSCD). Despite this, little is known regarding environmental drivers of lung function decline.

Objective: We hypothesized that environmental and socioeconomic variables have a significant effect on lung function in pwSCD that can be detected by spirometry.

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Objective: Assessing asthma control is an essential part of the outpatient management of children with asthma and can be performed through validated questionnaires such as the Asthma Control Test (ACT). Systematic approaches to incorporating the ACT in outpatient visits are often lacking, contributing to inconsistent completion rates. We conducted a quality improvement initiative to increase the proportion of visits where the ACT is completed for children with asthma in our multi-site pediatric pulmonary clinic network.

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Introduction: Asthma and obstructive sleep apnea (OSA) are chronic diseases that disproportionately affect children with sickle cell disease (SCD). The literature describes the negative impact that both conditions have on children with SCD separately; however, the effect of OSA on asthmatic children with OSA is less specific. We hypothesized that the presence of OSA in children with SCD and asthma is associated with specific hematologic markers, worse clinical outcomes, and greater healthcare utilization.

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Background: Intrinsic PEEP during mechanical ventilation occurs when there is insufficient time for expiration to functional residual capacity before the next inspiration, resulting in air trapping. Increased expiratory resistance (R), too rapid of a patient or ventilator breathing rate, or a longer inspiratory to expiratory time ratio (T/T) can all be causes of intrinsic PEEP. Intrinsic PEEP can result in increased work of breathing and patient-ventilator asynchrony (PVA) during patient-triggered breaths.

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Objective: Asthma is a recognized comorbidity in children with sickle cell disease (SCD). It increases the risk of acute chest syndrome (ACS), vaso-occlusive episodes, and early mortality. We aim to determine whether evaluation and management of children with SCD and asthma by a pulmonologist reduce rate of asthma exacerbation and ACS.

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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.

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Background: Stakeholders are often involved in evaluation, such as in the selection of specific research questions and the interpretation of results. Except for the topic of whether stakeholder involvement increases use, a paucity of research exists to guide practice regarding stakeholders.

Objectives: We address two questions: (1) If a third-party observer knows stakeholders were involved in an evaluation, does that affect the perceived credibility, fairness, and relevance of the evaluation? (2) Among individuals with a possible stake in an evaluation, which stakeholder group(s) do they want to see participate; in particular, do they prefer that multiple stakeholder groups, rather than a single group, participate?

Research Design: Six studies are reported.

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Bronchopulmonary dysplasia (BPD) was first described by Northway et al in 1967. This article describes the evolution of our understanding of the pathophysiology of BPD and the approaches to treatments of this illness developed over the past fifty years. These interventions had their roots in the understanding of the principles of the surface tension present at air-liquid interfaces, which were developed over 150 years before BPD's initial description.

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Introduction: Impulse oscillometry (IOS) employs high frequency sinusoidal or impulse pressure and flow waveforms to interrogate the mechanical properties of the respiratory system. It has special applications to preschool and younger children who may have difficulty performing the repetitive forced expiratory maneuvers required for spirometry.

Case Presentation: We present a case illustrating improvements of respiratory system mechanics measured by IOS in a 6-year-old child with cystic fibrosis (CF) who demonstrated clinical and radiological improvement after a course of therapy with hospitalization and intravenous antibiotics, and initiation of a cystic fibrosis transmembrane regulator (CFTR) protein corrector/potentiator agent.

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Chronic obstructive pulmonary disease (COPD) is a leading cause of disability and death of adults in the USA and worldwide. While environmental factors such as smoking and air pollution are major contributors to COPD, pediatric respiratory disease and more specifically early childhood wheezing are frequent predisposing factors. It is therefore possible that aggressive prevention and treatment of childhood respiratory illness may modify adult COPD risk.

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Purpose: E-cigarette or vaping product use associated lung injury (EVALI) has received national attention as an epidemic resulting in cases of significant morbidity and mortality. We aim to present the clinical and imaging findings in adolescents with pulmonary symptoms from suspected EVALI.

Methods: Chest radiographs and CTs of adolescents (< 19 years) with acute pulmonary symptoms and history of vaping were reviewed by two radiologists in consensus.

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Pretreatment and densification of agricultural residues at regional depots can simplify feedstock supply logistics for the production of biofuels in commercial biorefineries. We have previously reported the performance of a laboratory-scale (5 L) packed-bed ammonia fiber expansion (AFEX) reactor system, which showed significant promise for biomass pretreatment at distributed depots. In this paper, we describe the performance of a 90-fold larger pilot-scale packed-bed AFEX-reactor system, used to produce over 1,500 batches (~36 tons) of pretreated crop residues over a 5-year period.

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AFEX treatment of crop residues can greatly increase their nutrient availability for ruminants. This study investigated the concentration of acetamide, an ammoniation byproduct, in AFEX-treated crop residues and in milk and meat from ruminants fed these residues. Acetamide concentrations in four AFEX-treated cereal crop residues were comparable and reproducible (4-7 mg/g dry matter).

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Pulmonary complications of sickle cell disease (SCD) are diverse and encompass acute and chronic disease. The understanding of the natural history of pulmonary complications of SCD is limited, no specific therapies exist, and these complications are a primary cause of morbidity and mortality. We gathered a multidisciplinary group of pediatric and adult hematologists, pulmonologists, and emergency medicine physicians with expertise in SCD-related lung disease along with an SCD patient advocate for an American Thoracic Society-sponsored workshop to review the literature and identify key unanswered clinical and research questions.

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CHOPS syndrome is a multisystem disorder caused by missense mutations in AFF4. Previously, we reported three individuals whose primary phenotype included cognitive impairment and coarse facies, heart defects, obesity, pulmonary involvement, and short stature. This syndrome overlaps phenotypically with Cornelia de Lange syndrome, but presents distinct differences including facial features, pulmonary involvement, and obesity.

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Importance: The forced oscillation (FOT) and multiple breath washout (MBW) techniques are passive tests of lung function, and are reliable for preschool-age children. There has not been comparison testing to determine which test could more accurately differentiate between healthy controls and poorly controlled asthmatics, or differentiate a response to bronchodilator administration.

Objective: To determine whether the MBW and/or FOT could differentiate between healthy controls and poorly controlled asthmatics, and whether the two tests could detect a response to bronchodilator administration.

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Preschool children with asthma present a challenge in lung function testing, as they cannot readily cooperate with spirometry. The forced oscillation technique (FOT) measures passive pressures and flows delivered by a loudspeaker to a facemask, at frequencies much higher than those occurring physiologically. This in turn allows for rapid collection of data from a spontaneously breathing child in a timespan of seconds.

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Acetamide has been classified as a possible human carcinogen, but uncertainties exist about its levels in foods. This report presents evidence that thermal decomposition of N-acetylated sugars and amino acids in heated gas chromatograph injectors contributes to artifactual acetamide in milk and beef. An alternative gas chromatography/mass spectrometry protocol based on derivatization of acetamide with 9-xanthydrol was optimized and shown to be free of artifactual acetamide formation.

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