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Aim: To describe a novel clinical observation and to provide a review the literature about lung involvement in children with Crohn disease (CD)., Methods: An 8-year-old girl presented with pulmonary and hepatic granulomatous lesions, followed 6 months later by abdominal and general symptoms, resulting in the diagnosis of CD. Differential diagnosis between CD and sarcoidosis and a review of the literature about lung lesions in children with CD are discussed., Results: Crohn disease can be associated with pulmonary lesions, developing before, at the same time or after occurrence of digestive symptoms., Conclusions: This report highlights not only the importance of looking for lung lesions in CD but also underscores the necessity of considering the diagnosis of CD in incomplete presentation evoking sarcoidosis., (© 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.)

Lung diseases associated with surfactant metabolism disorders represent a significant but heterogeneous group of rare disorders. Intra-alveolar accumulation of protein related to surfactant dysfunction leads to cough, hypoxemia and radiological diffuse infiltration. Inherited deficiency of pulmonary surfactant protein B (SP-B) was initially described in term newborns who develop severe respiratory failure at birth. More recently, mutations in surfactant protein C (SP-C) or in proteins required for surfactant synthesis such as ATP-binding cassette, sub-family A, member 3 (ABCA3) or NK2 homeobox 1 (NKX2-1) were identified in newborns with respiratory distress but also in children with diffuse infiltrative pneumonia. The aim of this review is to describe the clinical presentation of these diseases but also the diagnostic tools and the treatments options available., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

Background: NKX2.1 mutations have been identified in patients displaying complete or partial brain-lung-thyroid syndrome, which can include benign hereditary chorea (BHC), hypothyroidism and/or lung disease., Aims and Methods: We evaluated the recently developed Multiplex Ligation-dependent Probe Amplification (MLPA) method to assess the relative copy number of genes. The goal was to determine if MLPA could improve, in addition to direct sequencing, the detection rate of NKX2.1 mutations in a phenotype-selected cohort of 24 patients affected by neurological, thyroid and/or pulmonary disorders., Results: Direct sequencing revealed two heterozygous mutations. Using MLPA, we identified two further heterozygous NKX2.1 gene deletions. MLPA increased the detection rate by 50%. All patients with gene deletions identified were affected by BHC and congenital hypothyroidism., Conclusion: MLPA should be considered as a complementary tool in patients with partial or total brain-lung-thyroid syndrome when direct sequencing failed to identify NKX2.1 mutations. All patients with an NKX2.1 mutation had BHC and congenital hypothyroidism, emphasizing the high prevalence of these signs associated with defective NKX2.1 alleles., (Copyright © 2012 S. Karger AG, Basel.)

Background: Insulin-like growth factors (IGF-I and -II) are pleiotropic regulators of somatic growth and development in vertebrate species. Endocrine and paracrine effects of both hormones are mediated by a common IGF type 1 receptor (IGF-1R). Lethal respiratory failure in neonatal IGF-1R knockout mice suggested a particular role for this receptor in pulmonary development, and we therefore investigated the consequences of IGF-1R inactivation in lung tissue., Methods and Findings: We first generated compound heterozygous mutant mice harboring a hypomorphic (Igf1r(neo)) and a null (Igf1r(-)) allele. These IGF-1R(neo/-) mice express only 22% of normal IGF-1R levels and are viable. In adult IGF-1R(neo/-) mice, we assessed lung morphology and respiratory physiology and found normal histomorphometric characteristics and normal breathing response to hypercapnia. We then generated homozygous IGF-1R knockout mutants (IGF-1R(-/-)) and analyzed their lung development during late gestation using histomorphometric and immunohistochemical methods. IGF-1R(-/-) embryos displayed severe lung hypoplasia and markedly underdeveloped diaphragms, leading to lethal neonatal respiratory distress. Importantly, IGF-1R(-/-) lungs from late gestation embryos were four times smaller than control lungs and showed markedly thickened intersaccular mesenchyme, indicating strongly delayed lung maturation. Cell proliferation and apoptosis were significantly increased in IGF-1R(-/-) lung tissue as compared with IGF-1R(+/+) controls. Immunohistochemistry using pro-SP-C, NKX2-1, CD31 and vWF as markers revealed a delay in cell differentiation and arrest in the canalicular stage of prenatal respiratory organ development in IGF-1R(-/-) mutant mice., Conclusions/significance: We found that low levels of IGF-1R were sufficient to ensure normal lung development in mice. In contrast, complete absence of IGF-1R significantly delayed end-gestational lung maturation. Results indicate that IGF-1R plays essential roles in cell proliferation and timing of cell differentiation during fetal lung development.

Background: The identification by CFTR mRNA studies of a new deep-intronic splicing mutation, c.870-1113_1110delGAAT, in one patient of our series with mild CF symptoms and in three CF patients of an Italian study, led us to evaluate the mutation frequency and phenotype/genotype correlations., Methods: 266 patients with CF and related disorders and having at least one undetected mutation, were tested at the gDNA level in three French reference laboratories., Results: In total, the mutation was found in 13 unrelated patients (5% of those already carrying a mutation) plus 4 siblings, including one homozygote and 12 heterozygotes having a severe CF mutation. The sweat test was positive in 10/14 documented cases, the diagnosis was delayed after 20 years in 9/15 and pancreatic insufficiency was present in 5/16., Conclusion: c.870-1113_1110delGAAT should be considered as CF-causing with phenotype variability and overall delayed diagnosis. Its frequency highlights the potential of mRNA studies., (Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: Acute bronchiolitis treatment in children and infants is largely supportive, but chest physiotherapy is routinely performed in some countries. In France, national guidelines recommend a specific type of physiotherapy combining the increased exhalation technique (IET) and assisted cough (AC). Our objective was to evaluate the efficacy of chest physiotherapy (IET + AC) in previously healthy infants hospitalized for a first episode of acute bronchiolitis., Methods and Findings: We conducted a multicenter, randomized, outcome assessor-blind and parent-blind trial in seven French pediatric departments. We recruited 496 infants hospitalized for first-episode acute bronchiolitis between October 2004 and January 2008. Patients were randomly allocated to receive from physiotherapists three times a day, either IET + AC (intervention group, n=246) or nasal suction (NS, control group, n=250). Only physiotherapists were aware of the allocation group of the infant. The primary outcome was time to recovery, defined as 8 hours without oxygen supplementation associated with minimal or no chest recession, and ingesting more than two-thirds of daily food requirements. Secondary outcomes were intensive care unit admissions, artificial ventilation, antibiotic treatment, description of side effects during procedures, and parental perception of comfort. Statistical analysis was performed on an intent-to-treat basis. Median time to recovery was 2.31 days, (95% confidence interval [CI] 1.97-2.73) for the control group and 2.02 days (95% CI 1.96-2.34) for the intervention group, indicating no significant effect of physiotherapy (hazard ratio [HR]=1.09, 95% CI 0.91-1.31, p=0.33). No treatment by age interaction was found (p=0.97). Frequency of vomiting and transient respiratory destabilization was higher in the IET + AC group during the procedure (relative risk [RR]=10.2, 95% CI 1.3-78.8, p=0.005 and RR=5.4, 95% CI 1.6-18.4, p=0.002, respectively). No difference between groups in bradycardia with or without desaturation (RR=1.0, 95% CI 0.2-5.0, p=1.00 and RR=3.6, 95% CI 0.7-16.9, p=0.10, respectively) was found during the procedure. Parents reported that the procedure was more arduous in the group treated with IET (mean difference=0.88, 95% CI 0.33-1.44, p=0.002), whereas there was no difference regarding the assessment of the child's comfort between both groups (mean difference=-0.07, 95% CI -0.53 to 0.38, p=0.40). No evidence of differences between groups in intensive care admission (RR=0.7, 95% CI 0.3-1.8, p=0.62), ventilatory support (RR=2.5, 95% CI 0.5-13.0, p=0.29), and antibiotic treatment (RR=1.0, 95% CI 0.7-1.3, p=1.00) was observed., Conclusions: IET + AC had no significant effect on time to recovery in this group of hospitalized infants with bronchiolitis. Additional studies are required to explore the effect of chest physiotherapy on ambulatory populations and for infants without a history of atopy., Trial Registration: ClinicalTrials.gov NCT00125450.

Congenital chondroid lesions of the lung are rare pathological findings. They are a constant feature of lung malformations such as giant cystic pulmonary chondroid hamartoma, chondroid cystic malformation, and in the "cartilaginous variant" of congenital adenomatoid malformation. All of these present as a large single thoracic mass.We present the cases of three males and two females with hitherto undescribed diffuse chondroid lung disease, all but one of whom had neonatal respiratory distress syndrome with interstitial syndrome on chest radiograph. The pathological findings were similar in all patients, showing large areas of disorganized lung parenchyma containing diffusely distributed mature cartilage islands. With a mean follow-up of 6 years, all patients had a favorable outcome. This diffuse chondroid lung disease appears to be a new entity whose initial presentation mimicked interstitial lung disease without the usual clinical, radiological, and histological features. We speculate that it could be part of a clinical spectrum between malformative chondroid lung cyst and congenital pulmonary airway malformation.

Objective: To document the epidemiological, clinical, histological and radiological characteristics of aggressive vascular abnormalities of bone in children., Study Design: Correspondents of the French Society of Childhood Malignancies were asked to notify all cases of aggressive vascular abnormalities of bone diagnosed between January 1988 and September 2009., Results: 21 cases were identified; 62% of the patients were boys. No familial cases were observed, and the disease appeared to be sporadic. Mean age at diagnosis was 8.0 years [0.8-16.9 years]. Median follow-up was 3 years [0.3-17 years]. The main presenting signs were bone fracture (n = 4) and respiratory distress (n = 7), but more indolent onset was observed in 8 cases. Lung involvement, with lymphangiectasies and pleural effusion, was the most frequent form of extraosseous involvement (10/21). Bisphosphonates, alpha interferon and radiotherapy were used as potentially curative treatments. High-dose radiotherapy appeared to be effective on pleural effusion but caused major late sequelae, whereas antiangiogenic drugs like alpha interferon and zoledrenate have had a limited impact on the course of pulmonary complications. The impact of bisphosphonates and alpha interferon on bone lesions was also difficult to assess, owing to insufficient follow-up in most cases, but it was occasionally positive. Six deaths were observed and the overall 10-year mortality rate was about 30%. The prognosis depended mainly on pulmonary and spinal complications., Conclusion: Aggressive vascular abnormalities of bone are extremely rare in childhood but are lifethreatening. The impact of anti-angiogenic drugs on pulmonary complications seems to be limited, but they may improve bone lesions.

NKX2-1 (NK2 homeobox 1) is a critical regulator of transcription for the surfactant protein (SP)-B and -C genes (SFTPB and SFTPC, respectively). We identified and functionally characterized two new de novo NKX2-1 mutations c.493C>T (p.R165W) and c.786_787del2 (p.L263fs) in infants with closely similar severe interstitial lung disease (ILD), hypotonia, and congenital hypothyroidism. Functional analyses using A549 and HeLa cells revealed that NKX2-1-p.L263fs induced neither SFTPB nor SFTPC promoter activation and had a dominant negative effect on wild-type (WT) NKX2-1. In contrast,NKX2-1-p.R165W activated SFTPC, to a significantly greater extent than did WTNKX2-1, while SFTPB activation was only significantly reduced in HeLa cells. In accordance with our in vitro data, we found decreased amounts of SP-B and SP-C by western blot in bronchoalveolar lavage fluid (patient with p.L263fs) and features of altered surfactant protein metabolism on lung histology (patient with NKX2-1-p.R165W). In conclusion, ILD in patients with NKX2-1 mutations was associated with altered surfactant protein metabolism, and both gain and loss of function of the mutated NKX2-1 genes on surfactant protein promoters were associated with ILD in "Brain-Lung-Thyroid syndrome"., ((c) 2009 Wiley-Liss, Inc.)

Background: This retrospective, single-center study was designed to assess our management strategy based on blebs detection on the initial CT scan., Methods: Children younger than aged 18 years presenting with a primary spontaneous pneumothorax (PSP) between 2000 and 2007 in a University Children's Hospital (hospital Armand Trousseau, Paris, France) were included in this study., Results: Twenty-five children who presented with PSP were included. The mean age was 14.2 +/- 1.9 years, and the sex ratio was 2.1. There was no significant difference between patients with or without blebs with regard to the anthropomorphic data or the side of the pneumothorax. Six patients had recurrence, which, in most cases, was a grade 1 pneumothorax. Fourteen (56%) children showed blebs on CT scan, which was ipsilateral or bilateral in 13 cases and contralateral in 1 case. Eleven of these children had surgery, and all the remaining patients (n = 3) had recurrence. All the patients, except one, presenting blebs on the preoperating CT scan, showed blebs on the subsequent surgery (predictive positive value = 92%), and the CT-scan sensibility for blebs was 75%., Conclusions: In children, blebs detection on CT scan has a good sensitivity and may be a useful tool to determine the indication of lung surgery to prevent PSP recurrence.

Interstitial lung diseases (ILDs) comprise a group of lung disorders characterized by various levels of inflammation and fibrosis. The current understanding of the mechanisms underlying the development and progression of ILD strongly suggests a central role of the alveolar epithelium. Following injury, alveolar epithelial cells (AECs) may actively participate in the restoration of a normal alveolar architecture through a coordinated process of re-epithelialization, or in the development of fibrosis through a process known as epithelial-mesenchymal transition (EMT). Complex networks orchestrate EMT leading to changes in cell architecture and behaviour, loss of epithelial characteristics and gain of mesenchymal properties. In the lung, AECs themselves may serve as a source of fibroblasts and myofibroblasts by acquiring a mesenchymal phenotype. This review covers recent knowledge on the role of alveolar epithelium in the pathogenesis of ILD. The mechanisms underlying disease progression are discussed, with a main focus on the apoptotic pathway, the endoplasmic reticulum stress response and the developmental pathway.

Objectives: To describe the long-term course and the management in children of chronic interstitial lung disease associated with I73T mutation., Materials and Methods: Clinical, radiological, and histological data from one family including five children and two adults were analyzed retrospectively for three patients and prospectively for the others., Results: Mean age of onset of respiratory symptoms for children was 6 months (2-15 months). The follow up was 14 months to 15 years (mean 55 months). The children were treated by intravenous high dose methylprednisolone pulses (6-15, mean 12). Four received oral prednisolone (mean 16 months) and hydroxychloroquine, one of these had additional mycophenolate mofetil. One adult with mild respiratory symptoms in infancy and another who was symptom free were also diagnosed. Both of them received no treatment. BAL fluids were obtained in all children: pro-SPC and SPB were positive in all. Lung biopsies were performed in two children respectively at 7 months, showing interstitial pneumonia features with endoluminal macrophage and type II alveolar cells hyperplasia, and at 33 months, showing subpleural microbullae, areas of interstitial pneumonia and type II alveolar cells hyperplasia. Immunohistochemistry showed for both an increased SPB and TTF1 staining in type II cells nuclei and a faint staining for pro-SPC and for ABCA3. Genetic diagnosis obviated the need for biopsy in other cases. The clinical status progressively improved and oxygen supplementation could be stopped after 3-14 months (mean 9 months). The CT scans initially showed ground glass opacities, then reduction in the ground glass pattern associated with clinical improvement and development of cysts., Conclusion: This kindred illustrates the variability of respiratory involvement and prognosis. It confirms the value of genetic screening for surfactant protein genes mutations., ((c) 2009 Wiley-Liss, Inc.)

We report a case of a 13-year-old girl with an asymptomatic isoniazid-resistant tuberculosis contact. Six months after the contact had been made, chest radiography showed left upper lobe infiltrates without hilar lymphadenopathy, which led to the start of an antituberculous treatment. Tuberculin skin test remained negative and blood tests showed hypereosinophilia. One month after the onset of the treatment, she presented with asthenia, weight loss, and cough. She was admitted to our unit with a diagnosis of drug-resistant tuberculosis. Blood tests showed the persistence of hypereosinophilia. Chest radiograph and high-resolution lung computed tomography (CT) scan showed alveolar peripheral condensations on both upper lobes without significant hilar lymphadenopathy. Bronchoalveolar lavage (BAL) showed a normal total cell count with 44% of eosinophils. Microbiological analyses were all negative. Chronic eosinophilic pneumonia (CEP) was confirmed after the elimination of other different eosinophilic lung diseases. The patient was highly responsive to high doses of oral corticosteroids. Dyspnoea and cough disappeared within one week and chest CT scan showed regression of the lung infiltrates within one month. No relapse occurred during the following nine months.

Lung diseases associated with surfactant-metabolism disorders are a heterogeneous group of rare diseases. Intra-alveolar accumulation of protein related to surfactant dysfunction leads to cough, hypoxemia, and radiological-diffuse infiltration. Inherited deficiency of pulmonary surfactant protein B (SP-B) was initially described in infants who develop respiratory failure at birth. More recently, mutations in other constitutive surfactant proteins, such as surfactant protein C or implied in its metabolism, such as ATP-binding cassette, subfamily A, member 3 (ABCA3) and thyroid transcription factor 1 (TTF-1) were identified in newborns with respiratory distress as well as in children with chronic-infiltrative pneumonia. The aim of this review is therefore to summarize the current state of our knowledge in this area.

Objective: Palivizumab (Synagis [Abbot Laboratories, Kent, United Kingdom]) is recommended for the prevention of severe lower respiratory tract infections caused by respiratory syncytial virus in infants at high risk. These injections are very painful, and currently the use of analgesics is not systematic. The objective of this study was to compare the efficacy of EMLA with premixed 50% nitrous oxide/oxygen, used alone or combined with EMLA, for pain alleviation during palivizumab injections., Methods: This randomized, double-blind, multicenter study included children who were younger than 24 months. Each child randomly received during the first 3 monthly injections 3 different analgesic interventions: (1) EMLA: application of EMLA plus air inhalation; (2) nitrous oxide/oxygen: inhalation of 50/50 nitrous oxide/oxygen plus application of a placebo cream; and (3) nitrous oxide/oxygen plus EMLA: inhalation of 50/50 nitrous oxide/oxygen plus application of EMLA. Each child was his or her own control. Procedural pain was assessed through videotapes with the Modified Behavioral Pain Scale. The procedure itself was subdivided in 2 periods: (1) injection and (2) recovery (first 30 seconds after the removal of the needle). Modified Behavioral Pain Scale scores over time (injection and recovery periods) and among treatments were compared by repeated-measures analysis of variance., Results: Fifty-five children were included. Mean +/- SD Modified Behavioral Pain Scale pain scores for EMLA, nitrous oxide/oxygen, and nitrous oxide/oxygen plus EMLA were, respectively, 9.3 +/- 1.0, 8.8 +/- 1.2, and 8.2 +/- 1.8 during the injection and 7.8 +/- 1.7, 7.4 +/- 1.9, and 6.9 +/- 2.4 during the recovery period. A significant time and treatment effect in favor of the combined nitrous oxide/oxygen plus EMLA was observed., Conclusions: The administration of 50/50 nitrous oxide/oxygen to infants and young children is effective in decreasing the pain associated with palivizumab intramuscular injections. The combined nitrous oxide/oxygen plus EMLA cream was more effective than either EMLA cream or nitrous oxide/oxygen alone.

Study Objectives: The objectives of the study were to present our institutional experience of idiopathic chylothorax in children and to propose therapeutic strategies., Design: This was a retrospective, single-center study., Patients: Patients were 6 children (4 boys, 2 girls) presenting with an idiopathic chylothorax diagnosed from the presence of a chylous pleural effusion with triglycerides greater than 1.2 mmol/L and a cellularity greater than 1000 cells/mL with a predominance of lymphocytes., Results: Median age of onset was 7 years (range, 2-14 years). Initial symptoms included cough (n = 4), tachypnea (n = 4), asthenia (n = 5), abdominal pain (n = 2), and bronchitis (n = 1). Chest radiography showed 2 left, 2 right, and 2 bilateral pleural effusions. Serum biology assessment was normal in all children. Respiratory function assessment at diagnosis revealed a decrease in functional residual capacity in 3 children and a decrease in lung diffusing capacity in 2 children. Initially, all patients received a medium-chain triglyceride diet for 29 months (range, 10-50 months). Total parenteral nutrition was required for 4 patients (for 1-4 months), and somatostatin was tried in one child. Two children required pleuroperitoneal shunting, bilateral in one case. During the follow-up (median duration, 6 years; range, 2-16 years), chylothorax stabilized in all patients and 5 patients were able to return to a normal diet., Conclusion: A medium-chain triglyceride diet associated in some cases with total parenteral nutrition may stabilize idiopathic chylothorax in children. In cases where conservative treatment has failed, pleuroperitoneal shunting may be useful.

The aim of this work was to evaluate the effect of a more conservative use of chest-tube insertion on the short-term and long-term outcome of pleural infection. Sixty-five patients with pleural infection, aged 1 month to 16 years were each treated according to one of the two protocols: classical management with chest-tube insertion (classical group, n = 33), or conservative use of chest-tube insertion (conservative group, n = 32), with drainage indicated only in the case of voluminous pleural effusion defined by a mediastinal shift and respiratory distress and/or an uncontrolled septic situation. The two groups were comparable with regard to age, baseline C-reactive protein (CRP) value and white blood cell counts, pleural thickness, identified bacteria, and antibiotic treatment. Chest-tube insertion was performed in 17 patients (52%) of the classical group compared to eight patients (25%) of the conservative group (P = 0.03). Duration of temperature above 39 degrees C was shorter in the conservative group (10 +/- 1 vs. 14 +/- 1 days, P = 0.01), as was the normalization of CRP (13 +/- 1 vs. 17 +/- 1 days, P = 0.03). Duration of hospitalization and intravenous (IV) antibiotherapy as well as the delay of chest-radiograph normalization was not significantly different between the two groups. A more conservative use of chest-tube insertion did not change short- and long-term outcome of the pleural infection in children. Drainage could be restricted to the most severely affected patients with pleural empyema causing a mediastinal shift and respiratory distress and/or presenting with an uncontrolled septic situation.

Background: Cellular responses to aging and oxidative stress are regulated by type 1 insulin-like growth factor receptor (IGF-1R). Oxidant injury, which is implicated in the pathophysiology of a number of respiratory diseases, acutely upregulates IGF-1R expression in the lung. This led us to suspect that reduction of IGF-1R levels in lung tissue could prevent deleterious effects of oxygen exposure., Methods: Since IGF-1R null mutant mice die at birth from respiratory failure, we generated compound heterozygous mice harboring a hypomorphic (Igf-1rneo) and a knockout (Igf-1r-) receptor allele. These IGF-1Rneo/- mice, strongly deficient in IGF-1R, were subjected to hyperoxia and analyzed for survival time, ventilatory control, pulmonary histopathology, morphometry, lung edema and vascular permeability., Results: Strikingly, after 72 h of exposure to 90% O2, IGF-1Rneo/- mice had a significantly better survival rate during recovery than IGF-1R+/+ mice (77% versus 53%, P < 0.05). The pulmonary injury was consistently, and significantly, milder in IGF-1Rneo/- mice which developed conspicuously less edema and vascular extravasation than controls. Also, hyperoxia-induced abnormal pattern of breathing which precipitated respiratory failure was elicited less frequently in the IGF-1Rneo/- mice., Conclusion: Together, these data demonstrate that a decrease in IGF-1R signaling in mice protects against oxidant-induced lung injury.

Interstitial lung disease (ILD) in children represents a heterogeneous group of rare lung disorders characterised by an inflammatory process of the alveolar wall and the pulmonary interstitium, which share common clinical, radiological and histological findings. Clinical presentation of paediatric ILD is non-specific and variable. Respiratory signs and symptoms include tachypnoea, rapid shallow breathing, retractions, cyanosis and crackles. Failure to thrive and respiratory distress are common in infants. Dyspnoea on exertion is a symptom encountered in older children. Non-respiratory symptoms can be present when ILD is part of a systemic disorder. Although non-specific and variable, the clinical presentation at the time of diagnosis has some prognostic value.

Transgenic mice, in which the level of surfactant protein (SP)-B mature peptide varied 5.6-fold between SP-B(+/-) and SP-B-overexpressing lines (SP-B+/+/+), were used to test the hypothesis that SP-B protects against endotoxin-induced lung inflammation. Intratracheal administration of endotoxin resulted in significantly lower concentration of SP-B mature peptide and elevated levels of total protein in bronchoalveolar lavage fluid of SP-B(+/-) mice compared with SP-B-overexpressing mice, indicating that endotoxin treatment leads to impairment of SP-B expression coincident with increased lung injury in SP-B(+/-) mice. Recruitment of inflammatory cells and elaboration of proinflammatory cytokines in bronchoalveolar lavage fluid were reduced in SP-B-overexpressing mice compared with SP-B(+/-) mice, suggesting that SP-B inhibited endotoxin-induced lung inflammation. Lung compliance and tissue damping were significantly decreased in SP-B(+/+) and SP-B(+/-) mice, but were not changed in SP-B(+/+/+) mice, consistent with a protective effect of SP-B. The minimum surface tension of large aggregate surfactant was significantly lower for surfactant isolated from SP-B-overexpressing mice, both in the absence and the presence of added plasma proteins. These data suggest that SP-B protected against endotoxin-induced lung inflammation by enhancing surfactant function, resulting in reduced lung injury, decreased influx of inflammatory cells, and lower cytokine levels; in contrast, levels of SP-B in SP-B(+/-) mice were further decreased by endotoxin treatment, likely exacerbating lung injury in this group.

Diseases of the lymphatic system in children include a group of exceptional conditions difficult to manage. The anatomy of lymphatic system is complex in the lung. Variable from one subject to another, its complex physiology plays an important role in air-blood exchanges occurring in the lung. In the pulmonary interstitium and in the pleura, the lymphatic system acts like an overflow valve capable of regulating variations in interstitial fluid. The presence or development of dysplasic lymphatics causes leakage, dilatation, and reflux of the lymph through incontinent valves leading to chylothorax and/or fluid overload in the pulmonary interstitium. Symptomatic care is usually proposed, based on a fat-free diet supplemented with light-chain triglycerides and liposoluble vitamins. Other therapeutic options can be proposed. Medical options include cytotoxic agents, somatostatin, and interferon-alpha. Surgery may also be useful, but an assessment of therapeutic efficacy is very difficult due to partial effects and the small number of cases studied.

In the past few years since the cloning of the gene defective in cystic fibrosis, much has been learned on the function of the protein cystic fibrosis transmembrane conductance regulator (CFTR) and on the mechanisms regulating its expression. Based on the current understanding of the processes involved in lung disease progression, a number of approaches have been developed using not only gene therapy, but also pharmacological agents. Several of these agents have been reported to restore function to CFTR with specific mutations.

To assess the role of lysozyme in pulmonary host defense in vivo, transgenic mice expressing rat lysozyme cDNA in distal respiratory epithelial cells were generated. Two transgenic mouse lines were established in which the level of lysozyme protein in bronchoalveolar (BAL) lavage fluid was increased 2- or 4-fold relative to that in WT mice. Lung structure and cellular composition of BAL were not altered by the expression of lysozyme. Lysozyme activity in BAL was significantly increased (6.6- and 17-fold) in 5-wk-old animals from each transgenic line. To determine whether killing of bacteria was enhanced by expression of rat lysozyme, 5-wk-old transgenic mice and WT littermates were infected with 10(6) CFU of group B streptococci or 10(7) CFU of a mucoid strain of Pseudomonas aeruginosa by intratracheal injection. Killing of group B streptococci was significantly enhanced (2- and 3-fold) in the mouse transgenic lines at 6 h postinfection and was accompanied by a decrease in systemic dissemination of pathogen. Killing of Pseudomonas aeruginosa was also enhanced in the transgenic lines (5- and 30-fold). Twenty-four hours after administration of Pseudomonas aeruginosa, all transgenic mice survived, whereas 20% of the WT mice died. Increased production of lysozyme in respiratory epithelial cells of transgenic mice enhanced bacterial killing in the lung in vivo, and was associated with decreased systemic dissemination of pathogen and increased survival following infection.

Retinoids, including retinol and retinoic acid (RA) derivatives, have been shown to be involved in the processes of lung development as well as of lung repair after injury. Recently, we have provided evidence that RA could stimulate proliferation of lung alveolar type 2 epithelial cells (E. Nabeyrat, V. Besnard, S. Corroyer, V. Cazals, and A. Clement. Am. J. Physiol. Lung Cell. Mol. Physiol. 275: L71-L79, 1998). To gain some insight into the mechanisms involved in the mitogenic action of RA, we focused in the present study on the effects of RA on the expression of G(1) phase cyclins and their cell cycle-dependent kinases (Cdks). Experiments were performed with serum-deprived cells cultured in the absence and presence of RA. The results showed no effects of RA on the expression of either cyclins or Cdks. In contrast, RA treatment was found to prevent the decrease in cyclin E-Cdk2 activity observed when cells were growth arrested by serum deprivation. The observation that changes in cyclin E-Cdk2 activity were not associated with modifications in the amount of complexes formed led to the suggestion that the Cdk inhibitory protein (CKI) was involved. Study of the CKI p21(CIP1) revealed marked differences in its expression in the absence and presence of RA, with a dramatic downregulation observed in RA-treated cells. Interestingly, immunoprecipitation experiments provided evidence that the decreased levels of p21(CIP1) were associated with a reduced interaction of this CKI with cyclin E-Cdk2 complexes. These data together with previous results obtained in various situations of type 2 cell growth arrest emphasize the role of p21(CIP1) in the control of lung alveolar epithelial cell proliferation.

A 3-year old child was admitted for a pneumococcal pneumonia with pleural effusion, initially treated with amoxicillin and clavulanic acid. Clinical deterioration suggested a resistance to conventional antibiotics which was confirmed by bacteriological investigation. A co-infection with respiratory syncitial virus and Mycoplasma pneumoniae was associated. Under adapted antibiotherapy, the clinical course improved.