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Due to the changing complex healthcare environment, educational innovation is essential to meet the needs of current and future neonatal-perinatal medicine (NPM) leaders. Greater clinical demands, decreased academic funding, and expanded graduate medical education program requirements have negatively impacted time for teaching and educational scholarship potentially limiting innovation in the field. By focusing on adult learning principles, embracing technology, and promoting collaboration, today's educators are preparing the next generation of neonatologists. Current innovations include regionalizing simulation boot camps, leveraging virtual learning to increase accessibility, developing niche training opportunities, and incorporating population health principles within existing quality initiatives. Areas in need of additional innovation include faculty and fellow development for teaching skills, expansion of educational networks, and dissemination and financial support of educational scholarship. These efforts and future innovations will require medical institutions and national NPM organizations to further invest in the medical educator as part of their missions.

Neonatal-perinatal medicine fellows must achieve a meaningful accomplishment in scholarly activity as part of their training. Despite the requirement for scholarly training in fellowship, there is a vanishingly small number of MD-only physician-scientists pursuing a research-oriented career. Recent neonatal trainees have identified several factors that preclude their careers in research-focused academic neonatology, including lower pay in academic positions, inadequate training in research techniques, and the perception that individuals in research careers have a poor work-life balance. High competition for limited pediatric research funds also contributes to a diminishing pool of physician-scientists in neonatology. This small number of physician-scientists is threatened by a high rate of attrition among physicians who enter this career path. In order to prevent further declines in the number of neonatal physician-scientists, we need improvements in funding and strong intra- and cross-institutional mentorship to foster individuals interested in a career as a physician-scientist.

Objective This study aimed to determine the value, strengths, and challenges of implementing an e-learning based flipped classroom (FC) educational modality as part of the standardized physiology National Neonatology Curriculum (NNC), created for neonatal-perinatal medicine (NPM) fellow learners and faculty educators. Study Design This is a cross-sectional study of NPM fellows and faculty educators who utilized at least one of the e-learning based NNC FC respiratory physiology programs between May and September 2018. Participants were surveyed anonymously regarding their experiences participating in the NNC, including measures of preparation time. A combination of descriptive statistics and proportion comparisons were used for data analysis. Results Among 172 respondents, the majority of fellow and faculty respondents reported positive attitudes toward the educational content and case discussions, and the majority supported national standardization of NPM physiology education (92%). Fellows reported greater preclass preparation for their FC compared with previous didactic lectures (30–60 vs. 0–15 minutes, p Conclusion Fellows and faculty educators supported the FC learning, reporting peer-to-peer learning, and the establishment of a learning community which promotes adult learning and critical thinking skills. A national physiology curriculum creates equitable and engaging educational experiences for all NPM fellows while reducing individual program burden of content creation. Our findings further supported the development of an NNC using a flipped classroom modality.

Bronchopulmonary dysplasia is a prevalent complication after extremely preterm birth. Inflammation with mechanical ventilation may contribute to its development. Whether hydrocortisone treatment after the second postnatal week can improve survival without bronchopulmonary dysplasia and without adverse neurodevelopmental effects is unknown.We conducted a trial involving infants who had a gestational age of less than 30 weeks and who had been intubated for at least 7 days at 14 to 28 days. Infants were randomly assigned to receive either hydrocortisone (4 mg per kilogram of body weight per day tapered over a period of 10 days) or placebo. Mandatory extubation thresholds were specified. The primary efficacy outcome was survival without moderate or severe bronchopulmonary dysplasia at 36 weeks of postmenstrual age, and the primary safety outcome was survival without moderate or severe neurodevelopmental impairment at 22 to 26 months of corrected age.We enrolled 800 infants (mean [±SD] birth weight, 715±167 g; mean gestational age, 24.9±1.5 weeks). Survival without moderate or severe bronchopulmonary dysplasia at 36 weeks occurred in 66 of 398 infants (16.6%) in the hydrocortisone group and in 53 of 402 (13.2%) in the placebo group (adjusted rate ratio, 1.27; 95% confidence interval [CI], 0.93 to 1.74). Two-year outcomes were known for 91.0% of the infants. Survival without moderate or severe neurodevelopmental impairment occurred in 132 of 358 infants (36.9%) in the hydrocortisone group and in 134 of 359 (37.3%) in the placebo group (adjusted rate ratio, 0.98; 95% CI, 0.81 to 1.18). Hypertension that was treated with medication occurred more frequently with hydrocortisone than with placebo (4.3% vs. 1.0%). Other adverse events were similar in the two groups.In this trial involving preterm infants, hydrocortisone treatment starting on postnatal day 14 to 28 did not result in substantially higher survival without moderate or severe bronchopulmonary dysplasia than placebo. Survival without moderate or severe neurodevelopmental impairment did not differ substantially between the two groups. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT01353313.).

To determine the relationship between level of supervision (LOS) ratings for the Common Pediatric Subspecialty Entrustable Professional Activities (EPAs) with their associated subcompetency milestones across subspecialties and by fellowship training year.Clinical Competency Committees (CCCs) in 14 pediatric subspecialties submitted LOS ratings for 6 Common Subspecialty EPAs and subcompetency milestone levels mapped to these EPAs. We examined associations between these subcompetency milestone levels and LOS ratings across subspecialty training year by fitting per-EPA linear mixed effects models, regressing LOS rating on milestone level and on training year.CCCs from 211 pediatric fellowship programs provided data for 369 first, 336 second, and 331 third year fellows. Mean subcompetency milestone levels increased similarly among subspecialties for most EPAs compared with the reference, Adolescent Medicine. Mean subcompetency milestones mapped to each EPA and mean EPA LOS ratings generally increased by training year across all subspecialties.Subcompetency milestones levels mapped to each Common Subspecialty EPA and the EPA LOS ratings increase similarly across subspecialties and by training year, providing validity evidence for using EPA LOS to assess pediatric subspecialty trainee performance. This study supports the development of tools to facilitated the CCC evaluation process across all pediatric subspecialties.

BACKGROUND AND OBJECTIVES Entrustable Professional Activities (EPAs) were developed to assess pediatric fellows. We previously showed that fellowship program directors (FPDs) may graduate fellows who still require supervision. How this compares with their expectations for entrustment of practicing subspecialists is unknown. METHODS We surveyed US FPDs in 14 pediatric subspecialties through the Subspecialty Pediatrics Investigator Network between April and August 2017. For each of 7 common pediatric subspecialty EPAs, we compared the minimum level of supervision that FPDs required for graduation with the level they expected of subspecialists for safe and effective practice using the Friedman rank sum test and paired t test. We compared differences between subspecialties using linear regression. RESULTS We collected data from 660 FPDs (response rate 82%). For all EPAs, FPDs did not require fellows to reach the level of entrustment for graduation that they expected of subspecialists to practice (P < .001). FPDs expected the least amount of supervision for the EPAs consultation and handovers. Mean differences between supervision levels for graduation and practice were smaller for clinical EPAs (consultation, handovers, lead a team) when compared with nonclinical EPAs (quality improvement, management, lead the profession and scholarship; P = .001) and were similar across nearly all subspecialties. CONCLUSIONS Fellowship graduates may need continued development of clinical and nonclinical skills in their early practice period, underscoring a need for continued assessment and mentoring. Graduation readiness must be based on clear requirements, with alignment of FPD expectations and regulatory standards, to ensure quality care for patients.

PURPOSE Entrustable professional activities (EPAs) are one approach to competency-based medical education (CBME), and 7 EPAs have been developed that address content relevant for all pediatric subspecialties. However, it is not known what level of supervision fellowship program directors (FPDs) deem necessary for graduation. The Subspecialty Pediatrics Investigator Network (SPIN) investigated FPD perceptions of the minimum level of supervision required for a trainee to successfully graduate. METHOD In 2017, SPIN surveyed all FPDs of accredited fellowships for 14 subspecialties. For each EPA, the minimum supervision level for graduation (ranging from observation only to unsupervised practice) was set such that no more than 20% of FPDs would accept a lower level. RESULTS The survey response rate was 82% (660/802). The minimum supervision level for graduation varied across the 7 EPAs from 2 (direct) to 4 (indirect for complex cases), with significant differences between EPAs. The percentage of FPDs desiring a lower minimum supervision level ranged from 3% to 17%. Compared with the 4 nonclinical EPAs (quality improvement, management, lead within the profession, scholarship), the 3 clinical EPAs (consultation, handover, lead a team) had higher minimum supervision graduation levels (P < .001), with less likelihood that an FPD would graduate a learner below their minimum level (P < .001). CONCLUSIONS Consensus among FPDs across all pediatric subspecialties demonstrates the potential need for ongoing supervision for graduates in all 7 common pediatric subspecialty EPAs after fellowship. As CBME programs are implemented, processes and infrastructure to support new graduates are important considerations for leaders.

Objectives: Fellowship program directors (FPD) and Clinical Competency Committees (CCCs) both assess fellow performance. We examined the association of entrustment levels determined by the FPD with those of the CCC for 6 common pediatric subspecialty entrustable professional activities (EPAs), hypothesizing there would be strong correlation and minimal bias between these raters. Methods: The FPDs and CCCs separately assigned a level of supervision to each of their fellows for 6 common pediatric subspecialty EPAs. For each EPA, we determined the correlation between FPD and CCC assessments and calculated bias as CCC minus FPD values for when the FPD was or was not a member of the CCC. In addition, we examined the effect of program size, FPD understanding of EPAs, and subspecialty on the correlations. Data were obtained in fall 2014 and spring 2015. Results: A total of 1040 fellows were assessed in the fall and 1048 in the spring. In both periods and for each EPA, there was a strong correlation between FPD and CCC supervision levels ( P Conclusions: The correlation between FPD and CCC assignment of EPA supervision levels is strong. Although slightly weaker when the FPD is not a CCC member, bias is small, so this is likely unimportant in determining fellow entrustment level. The similar performance ratings of FPDs and CCCs support the validity argument for EPAs as competency-based assessment tools.

Purpose: The learning environment encompasses the diverse physical locations, contexts, instructional methods, and cultures where learning occurs. Effective learning environments require preparation, promote collaboration, improve critical thinking, and increase learner engagement and knowledge retention. The Organization of Neonatal-Perinatal Medicine Training Program Directors (ONTPD) National Neonatology Curriculum (NNC) Randomized Controlled Trial (RCT) explored the impact of instructional methods on perceptions of the learning …

Author(s): D'Angio, CT; Wang, H; Hunn, JE; Pryhuber, GS; Chess, PR; Lakshminrusimha, S | Abstract: ObjectiveWe hypothesized that, among parents of potential neonatal research subjects, an accompanying cover sheet added to the permission form (intervention) would increase understanding of the research, when compared to a standard form (control).Study designThis pilot study enrolled parents approached for one of two index studies: one randomized trial and one observational study. A one-page cover sheet described critical study information. Families were randomized 1:1 to receive the cover sheet or not. Objective and subjective understanding and satisfaction were measured.ResultsThirty-two parents completed all measures (17 control, 15 intervention). There were no differences in comprehension score (16.8±5.7 vs 16.3±3.5), subjective understanding (median 6 vs 6.5), or overall satisfaction with consent (median 7 vs 6.5) between control and intervention groups (all Pg0.50).ConclusionA simplified permission form cover sheet had no effect on parents' understanding of studies for which their newborns were being recruited.

BackgroundCongenital diaphragmatic hernia (CDH) is commonly associated with pulmonary hypoplasia and pulmonary hypertension (PH). PH associated with CDH (CDH-PH) is frequently resistant to conventional pulmonary vasodilator therapy including inhaled nitric oxide (iNO) possibly due to right and left ventricular dysfunction. Milrinone is an intravenous inotrope and lusitrope with pulmonary vasodilator properties and has been shown anecdotally to improve oxygenation in PH. We developed this pilot study to determine if milrinone infusion would improve oxygenation in neonates ≥36weeks postmenstrual age (PMA) with CDH.Methods/designData on pulmonary vasodilator management and outcome of CDH patients was collected from 18 university NICUs affiliated with the Neonatal Research Network (NRN) from 2011 to 2012. The proposed pilot will be a masked, placebo-controlled, multicenter, randomized trial of 66 infants with CDH with an oxygenation index (OI) ≥10 or oxygen saturation index (OSI) ≥5. The primary outcome is the oxygenation response, as determined by change in OI at 24h after initiation of study drug. As secondary outcomes, we will determine oxygenation at 48h and 72h post-infusion, right ventricular pressures on echocardiogram and the incidence of systemic hypotension, arrhythmias, intracranial hemorrhage, survival without extracorporeal membrane oxygenation, and chronic lung disease (oxygen need at 28days postnatal age). Finally, we will evaluate the pulmonary and nutritional status at 4, 8 and 12months of age using a phone questionnaire.ResultsThree hundred thirty-seven infants with CDH were admitted to NRN NICUs in 2011 and 2012 of which 275 were ≥36weeks PMA and were exposed to the following pulmonary vasodilators: iNO (39%), sildenafil (17%), milrinone (17%), inhaled epoprostenol (6%), intravenous epoprostenol (3%), and intravenous PGE1 (1%). ECMO was required in 36% of patients. Survival to discharge was 71%.DiscussionCDH is an orphan disease with high mortality with few randomized trials evaluating postnatal management. Intravenous milrinone is a commonly used medication in neonatal/pediatric intensive care units and is currently used in 17% of patients with CDH within the NRN. This pilot study will provide data and enable further studies evaluating pulmonary vasodilator therapy in CDH.Trial registrationClinicalTrials.gov; NCT02951130; registered 14 October 2016.

Despite American College of Obstetricians and Gynecologists guidelines suggesting that non-urgent planned deliveries be scheduled at/after 39 weeks; elective delivery before 39 weeks occurs often in the United States. The objective of this study is to estimate the elective delivery rate between 36(0/7) and 38(6/7) weeks gestation and compare NICU admission rates between elective and non-elective deliveries. We conducted a retrospective cohort (n = 1,577) study. Charts were reviewed for all singleton deliveries (2006-2007) between 36(0/7) and 38(6/7) weeks gestation taking place at one hospital in NYS to determine delivery status. We computed adjusted relative risks (RR) with 95% confidence intervals (CI) for elective delivery in relation to NICU admission using robust Poisson regression. 32.8% of all births were elective: 20.7% of vaginal and 55.7% of cesarean births. Elective delivery increased with increasing gestational age. After controlling for potential confounders, infants born via a vaginal elective delivery (RR = 1.40, CI: 1.00, 1.94), an elective cesarean (RR = 2.05, CI: 1.53, 2.76), or a non-elective cesarean (RR = 2.00, CI: 1.50, 2.66) are at significantly increased risk of NICU admission compared to infants born via a non-elective vaginal delivery. Elective delivery before 39 weeks is common and increases the risk of infant NICU admission.

IMPORTANCE: Previous studies of myo-inositol in preterm infants with respiratory distress found reduced severity of retinopathy of prematurity (ROP) and less frequent ROP, death, and intraventricular hemorrhage. However, no large trials have tested its efficacy or safety. OBJECTIVE: To test the adverse events and efficacy of myo-inositol to reduce type 1 ROP among infants younger than 28 weeks’ gestational age. DESIGN, SETTING, AND PARTICIPANTS: Randomized clinical trial included 638 infants younger than 28 weeks’ gestational age enrolled from 18 neonatal intensive care centers throughout the United States from April 17, 2014, to September 4, 2015; final date of follow-up was February 12, 2016. The planned enrollment of 1760 participants would permit detection of an absolute reduction in death or type 1 ROP of 7% with 90% power. The trial was terminated early due to a statistically significantly higher mortality rate in the myo-inositol group. INTERVENTIONS: A 40-mg/kg dose of myo-inositol was given every 12 hours (initially intravenously, then enterally when feeding; n = 317) or placebo (n = 321) for up to 10 weeks. MAIN OUTCOMES AND MEASURES: Type 1 ROP or death before determination of ROP outcome was designated as unfavorable. The designated favorable outcome was survival without type 1 ROP. RESULTS: Among 638 infants (mean, 26 weeks’ gestational age; 50% male), 632 (99%) received the trial drug or placebo and 589 (92%) had a study outcome. Death or type 1 ROP occurred more often in the myo-inositol group vs the placebo group (29% vs 21%, respectively; adjusted risk difference, 7% [95% CI, 0%-13%]; adjusted relative risk, 1.41 [95% CI, 1.08-1.83], P = .01). All-cause death before 55 weeks’ postmenstrual age occurred in 18% of the myo-inositol group and in 11% of the placebo group (adjusted risk difference, 6% [95% CI, 0%-11%]; adjusted relative risk, 1.66 [95% CI, 1.14-2.43], P = .007). The most common serious adverse events up to 7 days of receiving the ending dose were necrotizing enterocolitis (6% for myo-inositol vs 4% for placebo), poor perfusion or hypotension (7% vs 4%, respectively), intraventricular hemorrhage (10% vs 9%), systemic infection (16% vs 11%), and respiratory distress (15% vs 13%). CONCLUSIONS AND RELEVANCE: Among premature infants younger than 28 weeks’ gestational age, treatment with myo-inositol for up to 10 weeks did not reduce the risk of type 1 ROP or death vs placebo. These findings do not support the use of myo-inositol among premature infants; however, the early termination of the trial limits definitive conclusions.

This article reviews exogenous surfactant therapy and its use in mitigating acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) in infants, children, and adults. Biophysical and animal research documenting surfactant dysfunction in ALI/ARDS is described, and the scientific rationale for treatment with exogenous surfactant is discussed. Major emphasis is on reviewing clinical studies of surfactant therapy in pediatric and adult patients with ALI/ARDS. Particular advantages from surfactant therapy in direct pulmonary forms of these syndromes are described. Also discussed are additional factors affecting the efficacy of exogenous surfactants in ALI/ARDS, including the multifaceted pathology of inflammatory lung injury, the effectiveness of surfactant delivery in injured lungs, and composition-based activity differences among clinical exogenous surfactant preparations.

A murine model of bone marrow transplant (BMT)-related lung injury was developed to study how infection sensitizes lung to the damaging effects of total body irradiation (TBI) at infectious and TBI doses that individually do not cause injury. Mice infected with Pneumocystis carinii exhibited an asymptomatic, rapid, and transient influx of eosinophils and T cells in bronchoalveolar lavage fluid (BALF). In contrast, mice infected with P. carinii 7 days before receiving TBI and syngeneic BMT ( P. carinii/TBI mice) exhibited severe pulmonary dysfunction, surfactant aggregate depletion, and surfactant activity reductions at 17 days post-BMT. BALF from P. carinii/TBI mice contained a disproportionate initial influx of CD4+T cells (CD4+:CD8+ratio of 2.7) that correlated with progressive lung injury (from 8 to 17 days post-BMT). Levels of TNF-α in BALF were significantly increased in P. carinii/TBI mice compared with mice given either insult alone, with peak values found at 11 days post-BMT. In vivo depletion of CD4+T cells in P. carinii/TBI mice abrogated pulmonary dysfunction and reduced TNF-α levels in BALF, whereas depletion of CD8+T cells did not affect lung compliance or TNF-α. Lung injury was not attributable to direct P. carinii damage, since CD4-depleted P. carinii/TBI mice that exhibited no injury had higher average lung P. carinii burdens than either mice given P. carinii alone or undepleted P. carinii/TBI mice. Together, these results indicate that P. carinii infection can sensitize the lung to subsequent TBI-mediated lung injury via a process dependent on non-alloreactive CD4+T cells.

Background Unwitnessed gastric aspiration can be a diagnostic dilemma, and early discrimination of different forms may help to identify individuals with increased risk of development of severe clinical acute lung injury or acute respiratory distress syndrome. The authors hypothesized that inflammatory mediator profiles could be used to help diagnose different types of gastric aspiration. Methods Diagnostic modeling using a newly modified receiver operator characteristic approach was applied to recently published data from our laboratory on lavaged inflammatory mediators from rodents given intratracheal normal saline, hydrochloric acid, small nonacidified gastric particles, or a combination of acid and small gastric particles. Multiple animal groups and postaspiration times of injury were analyzed to gauge the applicability of the predictive approach: rats (6 and 24 h), C57/BL6 wild-type mice (5 and 24 h), and transgenic mice on the same background deficient in the gene for monocyte chemoattractant protein 1 (MCP-1 [-/-] mice; 5 and 24 h). Results Overall, the four types of aspiration were correctly discriminated in 85 of 96 rats (89%), 72 of 78 wild-type mice (92%), and 59 of 73 MCP-1 (-/-) mice (81%) by models that used a maximum of only two mediators. The severe "two-hit" aspirate of the combination of acid and small gastric particles was correctly predicted in 21 of 24 rats, 23 of 23 wild-type mice, and 21 of 21 MCP-1 (-/-) mice. Specific best-fit mediators or mediator pairs varied with aspirate type, animal type, and time of injury. Cytokines and chemokines that best predicted the combination of acid and small gastric particles were cytokine-induced neutrophil chemoattractant 1 (6 h) and MCP-1 (24 h) in rats, tumor necrosis factor alpha/macrophage inflammatory protein 2 (5 h) and tumor necrosis factor alpha/MCP-1 (24 h) in wild-type mice, and tumor necrosis factor alpha/macrophage inflammatory protein 2 (5 h) and tumor necrosis factor alpha/keratinocyte-derived cytokine (24 h) in MCP-1 (-/-) mice. Conclusions These results support the potential feasibility of developing predictive models that use focused measurements of inflammatory mediators to help diagnose severe clinical forms of unwitnessed gastric aspiration, such as the combination of acid and small gastric particles, that may have a high risk of progression to acute lung injury/acute respiratory distress syndrome.

Mechanical strain is necessary for normal lung growth and development. Individuals with respiratory failure are supported with mechanical ventilation, leading to altered lung growth and injury. Understanding signaling pathways initiated by mechanical strain in lung epithelial cells will help guide development of strategies aimed at optimizing strain-induced lung growth while mitigating ventilator-induced lung injury. To study strain-induced proliferative signaling, focusing on the role of reactive oxidant species (ROS) and p42/44 mitogen-activated protein (MAP) kinase, human pulmonary epithelial H441 and MLE15 cells were exposed to equibiaxial cyclic mechanical strain. ROS were increased within 15 min of strain. N-acetylcysteine inactivated strain-induced ROS and inhibited p42/44 MAP kinase phosphorylation and strain-induced proliferation. PD98059 and UO126, p42/44 MAP kinase inhibitors, blocked strain-induced proliferation. To verify the specificity of p42/44 MAP kinase inhibition, cells were transfected with dominant-negative mitogen-activated protein kinase kinase-1 plasmid DNA. Transfected cells did not proliferate in response to mechanical strain. To determine whether strain-induced tyrosine kinase activity is necessary for strain-induced ROS-p42/44 MAP kinase signaling, genistein, a tyrosine kinase inhibitor, was used. Genistein did not block strain-induced ROS production or p42/44 MAP kinase phosphorylation. Gadolinium, a mechanosensitive calcium channel blocker, blocked strain-induced ROS production and p42/44 MAP kinase phosphorylation but not strain-induced tyrosine phosphorylation. These data support ROS production and p42/44 MAP kinase phosphorylation being involved in a common strain-induced signaling pathway, necessary for strain-induced proliferation in pulmonary epithelial cells, with a parallel strain-induced tyrosine kinase pathway.

This study examines surfactant dysfunction in rats with inflammatory lung injury from intratracheal instillation of hydrochloric acid (ACID, pH 1.25), small nonacidified gastric particles (SNAP), or combined acid and small gastric particles (CASP). Rats given CASP had the most severe lung injury at 6, 24, and 48 h based on decreases in arterial oxygenation and increases in erythrocytes, total leukocytes, neutrophils, total protein, and albumin in bronchoalveolar lavage (BAL). The content of large surfactant aggregates in BAL was reduced in all forms of aspiration injury, but decreases were greatest in rats given CASP. Large aggregates from aspiration-injured rats also had decreased levels of phosphatidylcholine (PC) and increased levels of lyso-PC and total protein compared with saline controls (abnormalities for CASP were greater than for SNAP or ACID alone). The surface tension-lowering ability of large surfactant aggregates on a bubble surfactometer was impaired in rats with aspiration injury at 6, 24, and 48 h, with the largest activity reductions found in animals given CASP. There were strong statistical correlations between surfactant dysfunction (increased minimum surface tension and reduced large aggregate content) and the severity of lung injury based on arterial oxygenation and levels of albumin, protein, and erythrocytes in BAL ( P < 0.0001). Surfactant dysfunction also correlated strongly with reduced lung volumes during inflation and deflation ( P = 0.0004–0.005). These results indicate that surfactant abnormalities are functionally important in gastric aspiration lung injury and contribute significantly to the increased severity of injury found in CASP compared with ACID or SNAP alone.

Laser flow cytometric analysis was used in conjunction with in vivo labeling with the lipophilic fluorescent dye DiIC18(5)-DS to discriminate resident alveolar macrophages from newly infiltrating monocytes/macrophages in mice with and without pulmonary influenza A virus infection. Leukocytes in bronchoalveolar lavage (BAL) and peripheral blood were analyzed by 2-color flow cytometry as a function of time following intravenous injection of DiIC18(5)-DS. At 4 hours, dye-positive leukocytes were present in both BAL and blood of normal mice, indicating that DiIC18(5)-DS rapidly crossed the pulmonary endothelial-epithelial barrier. At 4 days after dye injection, 98% of BAL cells were DiIC18(5)-DS positive, and almost all of these were monocytes/macrophages based on labeling with fluorescein isothiocyanate (FITC)-conjugated antibody to the Mac-3 marker. Only 3.2% +/- 0.3% of peripheral blood monocytes (approximately 0.16% of total peripheral blood leukocytes) were DiIC18(5)-DS positive at 6 days after injection, whereas > 95% of BAL leukocytes were strongly dye-positive on days 6 to 28. When DiIC18(5)-DS was injected in mice 6 days prior to intranasal challenge with influenza A, flow cytometry indicated that 57.8% 5.6% and 60.7% +/- 8.5% of macrophages/monocytes in BAL were newly infiltrated (i.e., DiIC18(5)-DS negative, Mac-3 positive) at 4 and 7 days, respectively, post viral infection. The discrimination of subpopulations of resident and newly recruited macrophages in BAL should facilitate future mechanistic studies on pulmonary infection and inflammatory lung injury.

Mechanical strain initiates a variety of responses in pulmonary epithelial cells. The signaling pathways and molecular alterations leading to these responses remain unclear. To identify novel signal transduction pathways activated by strain, macroarray analysis was performed on strained pulmonary epithelial cells. Glutathione S-transferase (GST) pi, GST mu, and heat shock protein (HSP)-27 were increased by strain. Western blotting verified that increases in cDNA of these redox-related molecules resulted in an increase in protein. Phosphorylation of HSP-27 was increased after strain, further supporting the role of HSP-27 in strain-induced signal transduction. Strain-induced oxidative stress was verified with the oxidant-sensitive dye dichlorodihydrofluorescein diacetate.

Background. Congenital diaphragmatic hernia (CDH) is a malformation of the diaphragm that allows bowel to enter the thoracic cavity, resulting in pulmonary hypoplasia and pulmonary hypertension. Approximately 50% of CDH patients are treated with extracorporeal membrane oxygenation (ECMO). The optimal gestational age for delivery of term infants with CDH at high risk for requiring ECMO is not known. The goal of this study was to compare survival of infants with CDH receiving ECMO born early term (38 0/7-39 6/7 weeks' gestation) with those born late term (40 0/7-41 6/7 weeks' gestation). Changes in survival rates of term infants and the factors associated with these changes were assessed over the 25 years that ECMO has been available. Methods. Design. Retrospective cohort study of infants with CDH treated with ECMO. Data Sources. The Extracorporeal Life Support Organization registry of patients treated at active Extracorporeal Life Support Organization centers from April 1976 through June 2001. Analysis. Survival and clinical predictors of survival were compared between infants born early term (38 0/7-39 6/7 weeks' gestation) and infants born late term (40 0/7-41 6/7 weeks' gestation). Changes in survival rates over time and factors associated with survival were evaluated. Results. Among full-term infants with CDH treated with ECMO, late-term compared with early-term delivery was associated with improved survival (63% vs 53%). Among full-term survivors of ECMO, late-term infants spent less time on ECMO (181 vs 197 hours) and less time in the hospital (60 vs 67 days). In multivariate analysis, greater birth weight, higher 5-minute Apgar score, higher arterial pH and Pco 2

Although oxygen is required for normal aerobic respiration, hyperoxia (95% O2/5% CO2) damages DNA, inhibits proliferation in G1, S and G2 phases of the cell cycle, and induces necrosis. The current study examines whether growth arrest in G1 protects pulmonary epithelial cells from oxidative DNA damage and cell death. Mv1Lu pulmonary adenocarcinoma cells were chosen for studies because hyperoxia inhibits their proliferation in S and G2 phase, while they can be induced to arrest in G1 by altering culture conditions. Hyperoxia inhibited proliferation, increased intracellular redox, and rapidly reduced clonogenic survival. In contrast, Mv1Lu cells treated with transforming growth factor (TGF)-β1, deprived of serum or grown to confluency, arrested and remained predominantly in G1 even during exposure. Growth arrest in G1 significantly enhanced clonogenic survival by 10–50-fold. Enhanced survival was not due to reduction in the intracellular redox-state of the cells, but instead was associated with reduced DNA strand breaks and p53 expression. Our findings suggest that the protective effects of G1 is mediated not simply by a reduction in intracellular ROS, but rather through an enhanced ability to limit or rapidly recognize and repair damaged DNA. J. Cell. Physiol. 193: 26–36, 2002. © 2002 Wiley-Liss, Inc.

Although the endothelial cell is the most abundant cell type in the differentiated lung, little is known about regulation of lung developmental vasculogenesis. Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen and angiogenic factor that has putative roles in vascular development. Mitogenic actions of VEGF are mediated by the tyrosine kinase receptor KDR/murine homologue fetal liver kinase Flk-1. HLF (hypoxia-inducible factor-like factor) is a transcription factor that increases VEGF gene transcription. Dexamethasone augments lung maturation in fetal and postnatal animals. However, in vitro studies suggest that dexamethasone blocks induction of VEGF. The objectives for the current study were to measure VEGF mRNA and Flk-1 mRNA in developing mouse lung and to measure the effects of dexamethasone treatment in vivo on VEGF and Flk-1 in newborn mouse lung. Our results show that VEGF and Flk-1 messages increase in parallel during normal lung development (d 13 embryonic to adult) and that the distal epithelium expresses VEGF mRNA at all ages examined. Dexamethasone (0.1-5.0 mg x kg(-1) x d(-1)) treatment of 6-d-old mice resulted in significantly increased VEGF, HLF, and Flk-1 mRNA. Dexamethasone did not affect cell-specific expression of VEGF, VEGF protein, or proportions of VEGF mRNA splice variants. These data suggest that the developing alveolar epithelium has an important role in regulating alveolar capillary development. In addition, unlike effects on cultured cells, dexamethasone, even in relatively high doses, did not adversely affect VEGF expression in vivo. The relatively high levels of VEGF and Flk-1 mRNA in adult lung imply a role for pulmonary VEGF in endothelial cell maintenance or capillary permeability.

Background.We previously demonstrated improved survival and early outcomes in a pilot trial of 2 doses of intravenous dexamethasone for infants with surfactant-treated respiratory distress syndrome.1 A multicenter, randomized, double-blind trial was undertaken to confirm these results.Methods.Infants Results.No differences were found in the dexamethasone versus placebo groups, respectively, regarding the primary outcomes of survival (79% vs 83%), survival without oxygen at 36 weeks' corrected gestational age (CGA; both 59%), and survival without oxygen at 36 weeks' CGA and without late glucocorticoid therapy (46% vs 44%). No significant differences between the groups in estimates from Kaplan-Meier survival analyses were found for median days on oxygen (50 vs 56 days), ventilation (20 vs 27 days), days to regain birth weight (15.5 vs 14 days), or length of stay (LOS; 88 vs 89 days). Infants given early dexamethasone were less likely to receive later glucocorticoid therapy for bronchopulmonary dysplasia during their hospitalization (27% vs 35%). No clinically significant side effects were noted in the dexamethasone group, although there were transient elevations in blood glucose and blood pressure followed by a return to baseline by study day 10. Among infants who died (40 vs 33), there were no differences in the median days on oxygen, ventilation, nor LOS. However, in survivors (149 vs 162), the following were observed: median days on oxygen 37 versus 45 days, ventilation 14 versus 19 days, and LOS 79 versus 81 days, for the dexamethasone versus placebo groups, respectively.Conclusions.This dose of early intravenous dexamethasone did not reduce the requirement for oxygen at 36 weeks' CGA and survival was not improved. However, early dexamethasone reduced the use of later prolonged dexamethasone therapy, and among survivors, reduced the median days on oxygen and ventilation. We conclude that this course of early dexamethasone probably represents a near minimum dose for instituting a prophylactic regimen against bronchopulmonary dys- plasia.

Cellular fibronectin (cFN) expression is characteristic of injured tissues. Unlike plasma FN, cFN mRNA often contains the EIIIA or EIIIB domains. We examined the lung cell-specific expression of total cFN mRNA and the EIIIA and EIIIB splice variants in rabbits after acute oxygen injury. By in situ hybridization, control lung had low cFN mRNA. After exposure to >95% oxygen, mRNAs for total cFN and EIIIA were noted primarily in alveolar macrophages and large-vessel endothelial cells. By 3–5 days recovery, cFN and EIIIA mRNA abundance was increased in alveolar septal cells (i.e., alveolar epithelial, interstitial, or endothelial cells) and in some large-vessel endothelial cells but was low in bronchial epithelial cells. During recovery, EIIIB mRNA was low in alveolar septal cells but was noted mainly in chondrocytes. Immunostaining for EIIIA increased during recovery, paralleling the in situ hybridizations. Because FN may modulate alveolar type II cell phenotype, we investigated type II cell cFN mRNA expression in vivo. During recovery, neither isolated type II cells nor cells with surfactant protein C mRNA in vivo contained FN mRNA. In summary, these data suggest that cFN with the EIIIA domain has a role in alveolar cell recovery from oxygen injury and that type II cells do not express cFN during recovery.

Objective. The objective of this case-control study was to develop a screening protocol using head ultrasound (HUS) to detect high-grade intraventricular hemorrhage (IVH) in very-low-birthweight infants with greater specificity than current practice, while maintaining a high degree of sensitivity. Materials and methods. All infants ≤ 32 weeks or ≤ 1500 g admitted to the neonatal intensive care unit between January 1, 1991 and December 31, 1992 were studied. The 1991 cohort was analyzed to identify the factors most sensitive and specific for predicting the occurrence of a high-grade (III or IV) IVH. Results. Eighty-five percent of infants born at 28–32 weeks gestation screened by 2 weeks of age for IVH had normal HUS scans. The factors most predictive of a high-grade IVH were gestational age < 28 weeks, forceps delivery, or any of the following in the first 2 weeks of life: seizures, head circumference increasing by more than 1 cm per week, base deficit ≥ 10, or cardiopulmonary resuscitation in the neonatal intensive care unit. Conclusion. Infants born at 28–32 weeks with a high-grade IVH can be identified with a high degree of sensitivity using refined screening criteria, eliminating 50 % of the HUS scans currently obtained for IVH screening.

Tyrosine kinases are important in the signal transduction of a number of growth factors. As shown previously, transforming growth factor (TGF)-alpha stimulated proliferation of type II cells in vitro. The mitogenic effect of TGF-alpha could be blocked by the addition of the tyrosine kinase inhibitors genistein or tyrphostin. Tyrosine phosphorylation in type II cells exposed to growth factors was examined using an antiphosphotyrosine antibody. After addition of TGF-alpha, phosphorylation of a tyrosine protein with a molecular mass of 170 kD, presumed to be the epidermal growth factor receptor (EGF-R), peaked by 5 min, returning to baseline by 30 min. As expected, genistein or tyrphostin decreased the TGF-alpha-induced phosphorylation of the EGF-R. Addition of TGF-beta resulted in no newly phosphorylated tyrosine proteins. TGF-beta decreased the TGF-alpha-induced phosphorylation of the EGF-R. Previous work has shown that TGF-beta blocks the TGF-alpha stimulation of type II cell proliferation. It appears that TGF-beta interferes with TGF-alpha-induced phosphorylation of the EGF-R.

High tidal volume mechanical ventilation can cause inflammation and lung damage. Mechanical strain is also necessary for normal lung growth. The current work was performed to determine if mechanical ventilation with clinically utilized tidal volumes stimulates a proliferative response in the lung. Six- to 8-week-old C57/Bl6 mice, anesthetized with ketamine/xylozine, were ventilated for 6 hours with 10 mL/kg tidal volume, positive end-expiratory pressure (PEEP) 3cm H(2)O. Pulmonary function testing demonstrated decreased compliance within 3 hours of ventilation. Assessment of bronchoalveolar lavage (BAL) demonstrated no significant increase in lactate dehydrogenase, total lavagable cell number, or total protein after ventilation. There was evidence of inflammation in the lungs of ventilated mice, with an increased percentage of lymphocytes and neutrophils in BAL, and an increase in macrophage inflammatory protein (MIP)-2 and interleukin (IL)-1beta message in lung tissue. Immunohistochemistry of inflation-fixed lungs demonstrated increased alveolar cell proliferation, as measured by both proliferating cell nuclear antigen and Ki67 staining. Dual staining confirmed that proliferating cells labeled with proSP-B, demonstrating that ventilation induces proliferation of alveolar type II cells. Ventilation did not increase apoptosis in alveolar type II cells, as measured by TUNEL staining. Ventilation at low tidal volumes leads to a mild inflammatory response and alveolar epithelial cell proliferation.

Despite its potentially adverse effects on lung development and function, supplemental oxygen is often used to treat premature infants in respiratory distress. To understand how neonatal hyperoxia can permanently disrupt lung development, we previously reported increased lung compliance, greater alveolar simplification, and disrupted epithelial development in adult mice exposed to 100% inspired oxygen fraction between postnatal days 1 and 4. Here, we investigate whether oxygen-induced changes in lung function are attributable to defects in surfactant composition and activity, structural changes in alveolar development, or both. Newborn mice were exposed to room air or 40%, 60%, 80%, or 100% oxygen between postnatal days 1 and 4 and allowed to recover in room air until 8 wk of age. Lung compliance and alveolar size increased, and airway resistance, airway elastance, tissue elastance, and tissue damping decreased, in mice exposed to 60–80% oxygen; changes were even greater in mice exposed to 100% oxygen. These alterations in lung function were not associated with changes in total protein content or surfactant phospholipid composition in bronchoalveolar lavage. Moreover, surface activity and total and hydrophobic protein content were unchanged in large surfactant aggregates centrifuged from bronchoalveolar lavage compared with control. Instead, the number of type II cells progressively declined in 60–100% oxygen, whereas levels of T1α, a protein expressed by type I cells, were comparably increased in mice exposed to 40–100% oxygen. Thickened bundles of elastin fibers were also detected in alveolar walls of mice exposed to ≥60% oxygen. These findings support the hypothesis that changes in lung development, rather than surfactant activity, are the primary causes of oxygen-altered lung function in children who were exposed to oxygen as neonates. Furthermore, the disruptive effects of oxygen on epithelial development and lung mechanics are not equivalently dose dependent.

This study uses microarray analyses to examine gene expression profiles for Mycobacterium tuberculosis (Mtb) induced by exposure in vitro to bovine lung surfactant preparations that vary in apoprotein content: (i) whole lung surfactant (WLS) containing the complete mixture of endogenous lipids and surfactant proteins (SP)-A, -B, -C, and -D; (ii) extracted lung surfactant (CLSE) containing lipids plus SP-B and -C; (iii) column-purified surfactant lipids (PPL) containing no apoproteins, and (iv) purified human SP-A. Exposure to WLS evoked a multitude of transcriptional responses in Mtb, with 52 genes up-regulated and 23 genes down-regulated at 30min exposure, plus 146 genes up-regulated and 27 genes down-regulated at 2h. Notably, WLS rapidly induced several membrane-associated lipases that presumptively act on surfactant lipids as substrates, and a large number of genes involved in the synthesis of phthiocerol dimycocerosate (PDIM), a cell wall component known to be important in macrophage interactions and Mtb virulence. Exposure of Mtb to CLSE, PPL, or purified SP-A caused a substantially weaker transcriptional response (

Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) are characterized by rapid-onset respiratory failure following a variety of direct and indirect insults to the parenchyma or vasculature of the lungs. Mortality from ALI/ARDS is substantial, and current therapy primarily emphasizes mechanical ventilation and judicial fluid management plus standard treatment of the initiating insult and any known underlying disease. Current pharmacotherapy for ALI/ARDS is not optimal, and there is a significant need for more effective medicinal chemical agents for use in these severe and lethal lung injury syndromes. To facilitate future chemical-based drug discovery research on new agent development, this paper reviews present pharmacotherapy for ALI/ARDS in the context of biological and biochemical drug activities. The complex lung injury pathophysiology of ALI/ARDS offers an array of possible targets for drug therapy, including inflammation, cell and tissue injury, vascular dysfunction, surfactant dysfunction, and oxidant injury. Added targets for pharmacotherapy outside the lungs may also be present, since multiorgan or systemic pathology is common in ALI/ARDS. The biological and physiological complexity of ALI/ARDS requires the consideration of combined-agent treatments in addition to single-agent therapies. A number of pharmacologic agents have been studied individually in ALI/ARDS, with limited or minimal success in improving survival. However, many of these agents have complementary biological/biochemical activities with the potential for synergy or additivity in combination therapy as discussed in this article.

This study tests the hypothesis that the virulence factor hemolysin (Hly) expressed by extraintestinal pathogenic Escherichia coli contributes to surfactant dysfunction and lung injury in a rat model of gram-negative pneumonia. Rats were instilled intratracheally with CP9 (wild type, Hly-positive), CP9 hlyA (Hly-minus), CP9 /pEK50 (supraphysiological Hly), or purified LPS. At 6 h postinfection, rats given CP9 had a decreased percentage content of large surfactant aggregates in cell-free bronchoalveolar lavage (BAL), decreased large aggregate surface activity, decreased PaO2/FiO2ratio, increased BAL albumin/protein levels, and increased histological evidence of lung injury compared with rats given CP9 hlyA or LPS. In addition, rats given CP9/ pEK50 or CP9 had decreased large aggregate surface activity, decreased PaO2/FiO2ratios, and increased BAL albumin/protein levels at 2 h postinfection compared with rats given CP9 hlyA. The severity of permeability lung injury based on albumin/protein levels in BAL at 2 h was ordered as CP9 /pEK50 > CP9 > CP9 hlyA > normal saline controls. Total lung titers of bacteria were increased at 6 h in rats given CP9 vs. CP9 hlyA, but bacterial titers were not significantly different at 2 h, indicating that increased surfactant dysfunction and lung injury were associated with Hly as opposed to bacterial numbers per se. Further studies in vitro showed that CP9 could directly lyse transformed pulmonary epithelial cells (H441 cells) but that indirect lysis of H441 cells secondary to Hly-induced neutrophil lysis did not occur. Together, these data demonstrate that Hly is an important direct mediator of surfactant dysfunction and lung injury in gram-negative pneumonia.

Surfactant dysfunction was studied in C57BL/6 (B6), B6.SP-A(-/-), and B6.iNOS(-/-) mice with pulmonary mycoplasma infection (10(7) colony-forming units). Cell-free bronchoalveolar lavage (BAL) from uninfected B6.SP-A(-/-) versus B6 mice had a reduced content of very large aggregates (VLA) and an increase in intermediate large aggregates (ILA), with no difference in total large aggregates (LA = VLA + ILA). However, LA from uninfected B6.SP-A(-/-) versus B6 mice contained less protein and were more sensitive to inhibition by serum albumin and lysophosphatidylcholine in pulsating bubble studies in vitro. Infection with Mycoplasma pulmonis caused significant lung injury and surfactant abnormalities in B6.SP-A(-/-), B6.iNOS(-/-), and B6 mice at 24, 48, 72 h after infection compared with uninfected mice of the same strain. Analyses of time-pooled data indicated that mycoplasma-infected B6.SP-A(-/-) and B6.iNOS(-/-) mice had significantly lower levels of LA and higher protein/phospholipid ratios in BAL compared with infected B6 mice. Infected B6.iNOS(-/-) versus B6 mice also had increased minimum surface tensions on the pulsating bubble and decreased levels of surfactant protein (SP)-B in BAL. These results indicate that pulmonary mycoplasma infection in vivo causes lung injury and surfactant abnormalities that are dependent in part on iNOS and SP-A. In addition, SP-A deficiency modifies surfactant aggregate content and lowers the inhibition resistance of LA surfactant in vitro compared with congenic normal mice.

Bronchopulmonary dysplasia (BPD), initially described 40 years ago, is a dynamic clinical entity that continues to affect tens of thousands of premature infants each year. BPD was first characterized as a fibrotic pulmonary endpoint following severe Respiratory Distress Syndrome (RDS). It was the result of pulmonary healing after RDS, high oxygen exposure, positive pressure ventilation, and poor bronchial drainage secondary to endotracheal intubation in premature infants. With improved treatment for RDS, including surfactant replacement, oxygen saturation monitoring, improved modes of mechanical ventilation, antibiotic therapies, nutritional support, and infants surviving at younger gestations, the clinical picture of BPD has changed. In the following pages, we will summarize the multifaceted pathophysiologic factors leading to the pulmonary changes in "new" BPD, which is primarily characterized by disordered or delayed development. The contribution of hyperoxia and hypoxia, mechanical forces, vascular maldevelopment, inflammation, fluid management, patent ductus arteriosus (PDA), nutrition, and genetics will be discussed.

Organized and coordinated lung development follows transcriptional regulation of a complex set of cell-cell and cell-matrix interactions resulting in a blood-gas interface ready for physiologic gas exchange at birth. Transcription factors, growth factors, and various other signaling molecules regulate epithelial-mesenchymal interactions by paracrine and autocrine mechanisms. Transcriptional control at the earliest stages of lung development results in cell differentiation and cell commitment in the primitive lung bud, in essence setting up a framework for pattern formation and branching morphogenesis. Branching morphogenesis results in the formation of the conductive airway system, which is critical for alveolization. Lung development is influenced at all stages by spatial and temporal distribution of various signaling molecules and their receptors and also by the positive and negative control of signaling by paracrine, autocrine, and endocrine mechanisms. Lung bud formation, cell differentiation, and its interaction with the splanchnic mesoderm are regulated by HNF-3beta, Shh, Nkx2.1, HNF-3/Forkhead homolog-8 (HFH-8), Gli, and GATA transcription factors. HNF-3beta regulates Nkx2.1, a transcription factor critical to the formation of distal pulmonary structures. Nkx2.1 regulates surfactant protein genes that are important for the development of alveolar stability at birth. Shh, produced by the foregut endoderm, regulates lung morphogenesis signaling through Gli genes expressed in the mesenchyme. FGF10, produced by the mesoderm, regulates branching morphogenesis via its receptors on the lung epithelium. Alveolization and formation of the capillary network are influenced by various factors that include PDGF, vascular endothelial growth factor (VEGF), and retinoic acid. Epithelial-endothelial interactions during lung development are important in establishing a functional blood-gas interface. The effects of various growth factors on lung development have been demonstrated by gain- or loss-of-function studies in null mutant and transgenic mice models. Understanding the role of growth factors and various other signaling molecules and their cellular interactions in lung development will provide us with new insights into the pathogenesis of bronchopulmonary dysplasia and disorders of lung morphogenesis.

Organized and coordinated lung development follows transcriptional regulation of a complex set of cell-cell and cell-matrix interactions resulting in a blood-gas interface ready for physiologic gas exchange at birth. Transcription factors, growth factors, and various other signaling molecules regulate epithelial-mesenchymal interactions by paracrine and autocrine mechanisms. Transcriptional control at the earliest stages of lung development results in cell differentiation and cell commitment in the primitive lung bud, in essence setting up a framework for pattern formation and branching morphogenesis. Branching morphogenesis results in the formation of the conductive airway system, which is critical for alveolization. Lung development is influenced at all stages by spatial and temporal distribution of various signaling molecules and their receptors and also by the positive and negative control of signaling by paracrine, autocrine, and endocrine mechanisms. Lung bud formation, cell differentiation, and its interaction with the splanchnic mesoderm are regulated by HNF-3beta, Shh, Nkx2.1, HNF-3/Forkhead homolog-8 (HFH-8), Gli, and GATA transcription factors. HNF-3beta regulates Nkx2.1, a transcription factor critical to the formation of distal pulmonary structures. Nkx2.1 regulates surfactant protein genes that are important for the development of alveolar stability at birth. Shh, produced by the foregut endoderm, regulates lung morphogenesis signaling through Gli genes expressed in the mesenchyme. FGF10, produced by the mesoderm, regulates branching morphogenesis via its receptors on the lung epithelium. Alveolization and formation of the capillary network are influenced by various factors that include PDGF, vascular endothelial growth factor (VEGF), and retinoic acid. Epithelial-endothelial interactions during lung development are important in establishing a functional blood-gas interface. The effects of various growth factors on lung development have been demonstrated by gain- or loss-of-function studies in null mutant and transgenic mice models. Understanding the role of growth factors and various other signaling molecules and their cellular interactions in lung development will provide us with new insights into the pathogenesis of bronchopulmonary dysplasia and disorders of lung morphogenesis.

OBJECTIVE To report cases of neonates successfully treated with both exogenous surfactant and inhaled nitric oxide (INO). DESIGN Retrospective chart review of full term infants treated between January and May 1999 in the neonatal intensive care unit of The Children's Hospital at Strong, University of Rochester, Rochester, New York. PATIENTS Three full-term infants treated with surfactant and INO were identified. Each infant had severe acute respiratory failure (as a result of severe aspiration syndromes) and a clinical diagnosis of pulmonary hypertension and parenchymal lung disease in the absence of congenital malformations. INTERVENTIONS One infant received INO (20-40 ppm) followed by exogenous surfactant (100mg/kg); the other two received surfactant followed by INO. MAIN RESULTS All three infants exhibited a favorable response to treatment with these agents in terms of improved arterial oxygenation as summarized by oxygenation index and all survived to discharge home without referral for extracorporeal membrane oxygenation. CONCLUSIONS No adverse interactions were observed related to INO plus surfactant therapy. The responses of these critically ill infants were consistent with the hypothesis that the actions of INO in dilating the pulmonary microvasculature and of exogenous surfactant in stabilizing and recruiting alveoli are complementary and may lead to additive clinical benefits. These case results suggest that more extensive clinical studies are warranted for combined-modality therapy with INO and exogenous surfactant in patients with the acute respiratory distress syndrome.

Excessive or thick pulmonary secretions are a common clinical challenge in the neonatal population. Mucus accumulation can cause many life-threatening complications, including plugging of the endotracheal tube and increasing the risk of pulmonary infections. We report 3 premature neonates who had critical pulmonary collapse secondary to mucous plugging. Different conventional methods to liquefy mucus and facilitate removal of secretions were exhausted to no avail. The rescue use of DNase was effective in reestablishing airway patency. Thus, this drug could be a valuable tool in treating atelectasis and mucus-plugging in mechanically ventilated, premature neonates.

Pulmonary epithelial cells are exposed to mechanical strain during physiological breathing and mechanical ventilation. Strain regulates pulmonary growth and development and is implicated in volutrauma-induced fibrosis. The mechanisms of strain-induced effects are not well understood. It was hypothesized that mechanical strain induces proliferation of pulmonary epithelial cells and that this is mediated by signals initiated within seconds of strain. To test this hypothesis, human pulmonary adenocarcinoma H441 cells were strained in vitro. Cyclic as well as tonic strain resulted in increased cellular proliferation. Western blot analysis of strained cells demonstrated three newly phosphorylated tyrosine residues within 30 s of strain. Phosphorylation of mitogen-activated protein kinases p42/44 increased, electrophoretic mobility shift assay demonstrated activation of transcription factor activating protein-1, and immunohistochemistry demonstrated increased phosphorylation of c- jun in response to strain. The tyrosine kinase inhibitor genistein blocked the strain-induced proliferation. We conclude that strain induces proliferation in pulmonary epithelial cells and that tyrosine kinase activity is necessary to signal the proliferative response to mechanical strain.