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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.).

Measure the effectiveness of and preference for a standardized, national curriculum utilizing flipped classrooms (FC) in neonatal-perinatal medicine (NPM) fellowships.Multicentered equivalence, cluster randomized controlled trial of NPM fellowship programs randomized to receive standardized physiology education as in-class lectures (traditional didactic, TD arm) or as pre-class online videos followed by in-class discussions (FC arm). Four multiple-choice question quizzes and three surveys were administered to measure knowledge acquisition, retention, and educational preferences.530 fellows from 61 NPM fellowships participated. Quiz performance was comparable between groups at all time points (p = NS, TD vs FC at 4 time points). Post intervention, more fellows in both groups preferred group discussions (pre/post FC 42% vs. 58%, P = 0.002; pre/post TD 43% vs. 60%, P = 0.001). FC fellows were more likely to rate classroom effectiveness positively (FC/TD, 70% vs. 36%, P 0.001).FCs promote knowledge acquisition and retention equivalent to TD and FC modalities are preferred by fellows.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

CD40 is a 50 kDa transmembrane protein important for regulating B lymphocyte proliferation and differentiation. This novel activation antigen is primarily expressed by hematopoietic cells including B lymphocytes, follicular dendritic cells, and monocytes. Recently, human fibroblasts from a variety of tissues were shown to display CD40; however, its function was unknown. Cellular responses mediated by CD40 are naturally triggered by its counter-receptor, the CD40 ligand, which is displayed on activated T cells, mast cells, eosinophils, basophils, and B lineage cells. This study investigated the functional significance of CD40 expression on periodontal fibroblasts, in the context of periodontal inflammation. The experiments reported herein demonstrate constitutive CD40 expression on cultured periodontal ligament (PDL) and gingival fibroblasts. Interestingly, cells of gingival origin displayed up to 13-fold higher constitutive levels of CD40, versus fibroblasts from PDL. Interferon gamma (IFN gamma) treatment enhanced CD40 expression on PDL and gingival fibroblasts, with up to 61-fold induction of expression. Immunohistochemical staining was used to detect CD40 on fibroblastic cells in both normal and acutely inflamed gingival tissue. Expression of CD40 in inflamed tissue was significantly higher than in uninflamed tissue. Western blot analysis of anti-CD40 triggered cells revealed the induction of tyrosine phosphorylation on a 50 kDa protein in PDL and gingival fibroblasts. These results indicate that CD40 is an active signaling conduit in periodontal fibroblasts. This concept was further substantiated by the fact that CD40 engagement stimulated interleukin 6 (IL-6) production by gingival fibroblasts, but not periodontal ligament fibroblasts. Overall, these results demonstrate that CD40 on periodontal fibroblasts may functionally interact with CD40L-expressing cells. This CD40/CD40L interaction can stimulate fibroblast activation and synthesis of the proinflammatory cytokine IL-6.

Although the expression and function of CD40 on B lymphocytes has been well studied, the significance of CD40 on non-lymphoid cells such as keratinocytes (KC) is not as well characterized. We demonstrate in this report that CD40 is expressed by virtually all human KC, and that it functions as an important signaling molecule. Flow cytometry of undifferentiated and terminally differentiated KC indicated that both cell types expressed CD40, as determined by binding to monoclonal antibodies and a recombinant CD40 ligand fusion protein; interferon-gamma (IFN-gamma) treatment of KC increased CD40 expression. Cultured KC also expressed 1.5-kb CD40 transcripts. Activation of KC cell surface CD40 using the monoclonal antibody G28.5 resulted in the rapid generation of a 50-kDa tyrosine phosphorylated polypeptide, as well as a dose-dependent increase in the secretion of interleukin-6, a cytokine that has been linked to KC proliferation. KC also co-stimulated a significant T lymphocyte proliferative response to the mitogen phytohemagglutinin that was CD40 dependent. These data indicate that KC constitutively express a low level of functional CD40 and regulate their expression in response to IFN-gamma. These data support the concept that KC, via their expression of CD40, have the capacity to amplify inflammation in the skin by interacting with CD40 ligand-bearing T cells.

Objective To test the hypothesis that pressure-regulated volume control (PRVC), an assist/control mode of ventilation, would increase the proportion of very low-birth-weight infants who were alive and extubated at 14 days of age as compared with synchronized intermittent mandatory ventilation (SIMV). Study Design Ventilated infants with birth weight of 500 to 1249 g were randomized at less than 6 hours of age either to pressure-limited SIMV or to PRVC on the Servo 300 ventilator (Siemens Electromedical Group, Danvers, Mass). Infants received their assigned mode of ventilation until extubation, death, or meeting predetermined failure criteria. Results Mean ± SD birth weights were similar in the SIMV (888 ± 199 g, n = 108) and PRVC (884 ± 203 g, n = 104) groups. No differences were detected between SIMV and PRVC groups in the proportion of infants alive and extubated at 14 days (41% vs 37%, respectively), length of mechanical ventilation in survivors (median, 24 days vs 33 days, respectively), or the proportion of infants alive without a supplemental oxygen requirement at 36 weeks’ postmenstrual age (57% vs 63%, respectively). More infants receiving SIMV (33%) failed their assigned ventilator mode than did infants receiving PRVC (20%). Including failure as an adverse outcome did not alter the overall outcome (39% of infants in the SIMV group vs 35% of infants in the PRVC group were alive, extubated, and had not failed at 14 days). Conclusion In mechanically ventilated infants with birth weights of 500 to 1249 g, using PRVC ventilation from birth did not alter time to extubation.

In the September 2003 issue of Pediatrics , Stege et al1 discuss the effect of new therapies for congenital diaphragmatic hernia (CDH) on survival. They point out that studies reporting improved survival using high-frequency ventilation, extracorporeal membrane oxygenation, inhaled nitric oxide, and delayed surgery are flawed by selection … Address correspondence to Patricia R. Chess, MD, Departments of Pediatrics and Biomedical Engineering, University of Rochester, Box 850, 601 Elmwood Ave, Rochester, NY 14642. E-mail: patricia_chess{at}urmc.rochester.edu