Permission form synopses to improve parents' understanding of research: a randomized trial.

OBJECTIVE: We 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 DESIGN: This 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. RESULTS: Thirty-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 P>0.50). CONCLUSION: A simplified permission form cover sheet had no effect on parents' understanding of studies for which their newborns were being recruited.

Rescue use of DNase in critical lung atelectasis and mucus retention in premature neonates.

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.

Mechanical strain-induced proliferation and signaling in pulmonary epithelial H441 cells.

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.

Expression of vascular endothelial growth factor and Flk-1 in developing and glucocorticoid-treated mouse lung.

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.

Early dexamethasone-attempting to prevent chronic lung disease.

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 <30 weeks' gestation were eligible if they had respiratory distress syndrome, required mechanical ventilation at 12 to 18 hours of age, and had received at least 1 dose of exogenous surfactant. Infants were excluded if sepsis or pneumonia was suspected or if congenital heart disease or chromosomal abnormalities were present. A total of 384 infants were enrolled-189 randomized to dexamethasone (.5mg/kg birth weight at 12-18 hours of age and a second dose 12 hours later) and 195 to an equal volume of saline placebo. 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 dysplasia.

Cyclic strain induces proliferation of cultured embryonic heart cells.

Embryonic heart cells undergo cyclic strain as the developing heart circulates blood to the embryo. Cyclic strain may have an important regulatory role in formation of the adult structure. This study examines the feasibility of a computerized cell-stretching device for applying strain to embryonic cardiocytes to allow measurement of the cellular response. A primary coculture of myocytes and a secondary culture of nonmyocytes from stage-31 (7 d) embryonic chick hearts were grown on collagen-coated membranes that were subsequently strained at 2 Hz to 20% maximal radial strain. After 24 h, total cell number increased by 37+/-6% in myocyte cocultures and by 26+/-6% in nonmyocyte cultures over unstrained controls. Lactate dehydrogenase and apoptosis assays showed no significant differences in cell viabilities between strained and unstrained cells. After 2 h strain, bromodeoxyuridine incorporation was 38+/-1.2% versus 19+/-0.2% (P < 0.01) in strained versus unstrained myocyte cocultures, and 35+/-2.1% versus 16+/-0.2% (P = 0.01) in nonmyocyte cultures. MF20 antibody labeling and periodic acid-Schiff (PAS) staining estimated the number of myocytes in strained wells as 50-67% larger than in control wells. Tyrosine phosphorylation may play a role in the cellular response to strain, as Western blot analysis showed an increase in tyrosine phosphorylation of two proteins with approximate molecular weights of 63 and 150 kDa within 2 min of strain. The results of this study indicate that embryonic chick cardiocytes can be cultured in an active mechanical environment without significant detachment and damage and that increased proliferation may be a primary response to strain.

Combined-modality therapy with inhaled nitric oxide and exogenous surfactant in term infants with acute respiratory failure.

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.

Fulminant necrotizing enterocolitis in a premature neonate treated for supraventricular tachycardia.

A premature neonate with supraventricular tachycardia was treated prenatally and postnatally, without significant signs of congestive heart failure. Enteral feeding was initiated after 48 hours of age. The infant developed fatal, fulminant necrotizing enterocolitis 28 hours after starting feeds.

Cell-specific expression of fibronectin and EIIIA and EIIIB splice variants after oxygen injury.

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.

H441 pulmonary epithelial cell mitogenic effects and signaling pathways in response to HGF and TGF-alpha.

Pulmonary epithelial cells are important in lung growth, development, and injury. H441 pulmonary adenocarcinoma cells may be a useful model for studying pulmonary epithelial cell growth factor responses in vitro. Isolated pulmonary epithelial type II cells proliferate in response to transforming growth factor (TGF)-alpha via the epidermal growth factor (EGF) receptor. Type II cells also proliferate in response to hepatocyte growth factor (HGF). In the present study, H441 cell responses to these growth factors were examined, and compared to type II cells. Both the EGF-R and the c-met proto-oncogene receptor, to which HGF binds, were immunoprecipitated from H441 cells. In H441 cells, addition of TGF-alpha resulted in phosphorylation of the EGF receptor and increased cell number and tritiated thymidine incorporation. Incubation with HGF resulted in phosphorylation of its c-met proto-oncogene receptor in type II and H441 cells, and also increased cell number and tritiated thymidine incorporation. Both HGF and TGF-alpha stimulated phosphorylation of the intracellular signaling molecules p42 and p44 mitogen activated protein kinases in H441 cells. H441 cells exhibited responses to mitogenic growth factors similar to type II cells and may be useful as a model for type II cell growth factor responses and signal transduction.

CD40 is a functional activation antigen and B7-independent T cell costimulatory molecule on normal human lung fibroblasts.

CD40 is an important signaling and activation Ag found on certain bone marrow-derived cells. Recently, CD40 also has been shown to be expressed by mesenchymal cells, including human fibroblasts. Little is known about the role of CD40 in fibroblasts. The current study investigates the hypothesis that CD40 expressed on lung fibroblasts is an activation structure and mechanism for interaction with hemopoietic cells. Communication between resident tissue fibroblasts and T cells is necessary for normal wound healing, and can be pathologic, resulting in tissue fibrosis. Signaling through CD40 with soluble CD40 ligand stimulated fibroblast activation, as evidenced by mobilization of nuclear factor-kappaB and by induction of the proinflammatory and chemoattractant cytokines IL-6 and IL-8. IFN-gamma-primed lung fibroblasts costimulate T lymphocyte proliferation utilizing CD40, but not the well-studied costimulatory molecules B7-1 and B7-2. Data reported herein support the hypothesis that cognate interactions between tissue fibroblasts and infiltrating T lymphocytes, via the CD40/CD40L pathway, augment inflammation and may promote fibrogenesis by activating both cell types.

Screening head ultrasound to detect intraventricular hemorrhage in premature infants.

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 /= 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.

CD40 mediated activation of gingival and periodontal ligament fibroblasts.

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.

Tyrosine kinase activity is necessary for growth factor-stimulated rabbit type II pneumocyte proliferation.

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.