Bronchoalveolar Cell Research Articles

1′-Acetoxychavicol Acetate Isolated from Alpinia galanga Ameliorates Ovalbumin-Induced Asthma in Mice

The World Health Organization reports that 235 million people are currently affected by asthma. This disease is associated with an imbalance of Th1 and Th2 cells, which results in the upregulation of cytokines that promote chronic inflammation of the respiratory system. The inflammatory response causes airway obstruction and can ultimately result in death. In this study we evaluated the effect of 1′-acetoxychavicol acetate (ACA) isolated from Alpinia galanga rhizomes in a mouse model of ovalbumin (OVA)-induced asthma. To generate the mouse model, BALB/c mice were sensitized by intraperitoneal injection of OVA and then challenged with OVA inhalation for 5 days. Mice in the vehicle control group were sensitized with OVA but not challenged with OVA. Treatment groups received dexamethasone, 25 mg/kg/day ACA, or 50 mg/kg/day ACA for 5 days. Asthma-related inflammation was assessed by bronchoalveolar lavage fluid cell counts and histopathological and immunohistochemical analysis of lung tissues. Our results showed that ACA reduced the infiltration of white blood cells (especially eosinophils) and the level of IgE in the lungs of mice challenged with OVA and suppressed histopathological changes such as airway remodeling, goblet-cell hyperplasia, eosinophil infiltration, and glycoprotein secretion. In addition, ACA inhibited expression of the Th2 cytokines interleukin (IL)-4 and IL-13, and Th1 cytokines IL-12α and interferon-γ. Because asthmatic reactions are mediated by diverse immune and inflammatory pathways, ACA shows promise as an antiasthmatic drug candidate.

Epidemic of Lung Cancer in Patients With HIV Infection

The survival of patients with HIV infection has improved dramatically over the past 20 years, largely owing to a significant reduction in opportunistic infections and AIDs-defining malignancies, such as lymphoma and Kaposi sarcoma. However, with improved survival, patients with HIV are experiencing morbidity and mortality from other (non-AIDs-defining) complications, such as solid organ malignancies. Of these, the leading cause of mortality in the HIV-infected population is lung cancer, accounting for nearly 30% of all cancer deaths and 10% of all non-HIV-related deaths. Importantly, the average age of onset of lung cancer in the HIV-infected population is 25 to 30 years earlier than that in the general population and at lower exposure to cigarette smoke. This article provides an overview of the epidemiology of lung cancer in the HIV-infected population and discusses some of the important risk factors and pathways that may enhance the risk of lung cancer in this population.

Primed Infusion with Delayed Equilibrium of Gd.DTPA for Enhanced Imaging of Small Pulmonary Metastases

ObjectivesTo use primed infusions of the magnetic resonance imaging (MRI) contrast agent Gd.DTPA (Magnevist), to achieve an equilibrium between blood and tissue (eqMRI). This may increase tumor Gd concentrations as a novel cancer imaging methodology for the enhancement of small tumor nodules within the low signal-to-noise background of the lung.MethodsA primed infusion with a delay before equilibrium (eqMRI) of the Gd(III) chelator Gd.DTPA, via the intraperitoneal route, was used to evaluate gadolinium tumor enhancement as a function of a bolus injection, which is applied routinely in the clinic, compared to gadolinium maintained at equilibrium. A double gated (respiration and cardiac) spin-echo sequence at 9.4T was used to evaluate whole lungs pre contrast and then at 15 (representative of bolus enhancement), 25 and 35 minutes (representative of eqMRI). This was carried out in two lung metastasis models representative of high and low tumor cell seeding. Lungs containing discrete tumor nodes where inflation fixed and taken for haematoxylin and eosin staining as well as CD34 staining for correlation to MRI.ResultsWe demonstrate that sustained Gd enhancement, afforded by Gd equilibrium, increases the detection of pulmonary metastases compared to bolus enhancement and those tumors which enhance at equilibrium are sub-millimetre in size (<0.7 mm2) with a similar morphology to early bronchoalveolar cell carcinomas.ConclusionAs Gd-chelates are routinely used in the clinic for detecting tumors by MRI, this methodology is readily transferable to the clinic and advances MRI as a methodology for the detection of small pulmonary tumors.

Safety of and Cellular Response to Segmental Bronchoprovocation in Allergic Asthma

RationaleDespite its incorporation into research studies, the safety aspects of segmental allergen bronchoprovocation and differences in cellular response among different allergens have received limited consideration.MethodsWe performed 87 segmental challenges in 77 allergic asthma subjects. Allergen dose was based on each subject’s response to whole lung allergen challenge. Bronchoalveolar lavage was performed at 0 and 48 hours. Safety indicators included spirometry, oxygen saturation, heart rate, and symptoms.ResultsAmong subjects challenged with ragweed, cat dander, or house dust mite, there were no differences in safety indicators. Subjects demonstrated a modest oxygen desaturation and tachycardia during the procedure that returned to normal prior to discharge. We observed a modest reduction in forced vital capacity and forced expiratory volume in one second following bronchoscopy. The most common symptoms following the procedure were cough, sore throat and fatigue. Total bronchoalveolar lavage fluid cell numbers increased from 13±4 to 106±108×104 per milliliter and eosinophils increased from 1±2 to 44±20 percent, with no significant differences among the three allergens.ConclusionsIn mild allergic asthma, segmental allergen bronchoprovocation, using individualized doses of aeroallergens, was safe and yielded similar cellular responses.

Genetic Deficiency in Complement Component 4b Does Not Alter Radiation-Induced Lung Disease in Mice

Previous investigations have shown altered levels of complement components to be associated with radiation-induced lung disease. In this study we aimed to determine whether a deficiency in complement component 4b alters the lung response to irradiation of C57BL/6 mice. The pulmonary phenotype of C57BL/6 C4b(-/-) mice and their wild-type littermates was assessed following an 18 Gy single dose to the thoracic cavity. The assessed end points included, survival time postirradiation, bronchoalveolar lavage cell differential, hydroxyproline measures and histological evidence of alveolitis and fibrosis. The lung phenotype of C4b-deficient mice did not differ from that of wild-type mice in terms of survival time postirradiation, tissue hydroxyproline levels or by histological evidence of alveolitis or fibrosis. No differences in bronchoalveolar cell differential counts were evident among the irradiated mice grouped by C4b genotype. We concluded that a deficiency in C4b does not alter radiation-induced lung disease in the C57BL/6 mouse model.

Neutrophil and Eosinophil Granulocytes as Key Players in a Mouse Model of Chemical-Induced Asthma

Diisocyanates are an important cause of chemical-induced occupational asthma. This type of immunologically mediated asthma is often characterized by a predominant granulocytic inflammation in the airways, rather than an infiltration by lymphocytes. We sought to determine the contribution of granulocytes in the outcome of chemical-induced asthma using general and specific leukocyte depletion strategies in an established mouse model of isocyanate asthma. On days 1 and 8, BALB/c mice received dermal applications with toluene-2,4-diisocyanate (TDI) or vehicle (acetone olive oil), followed by two ip injections of cyclophosphamide (CP, days 11 and 13), or one iv injection of antigranulocyte receptor 1 (aGR1, day 13) monoclonal antibody (mAb), or two ip injections of Ly6G-specific mAb (1A8, days 13 and 14). On day 15, the mice were challenged (oropharyngeal administration) with TDI or vehicle. The next day, we assessed methacholine airway hyperreactivity (AHR); bronchoalveolar lavage differential cell count; histopathology and total serum IgE; and auricular lymphocyte subpopulations and release of interleukin (IL)-2, IL-4, IL-10, IL-13, and gamma interferon by these lymphocytes. CP depleted all leukocyte types and completely prevented AHR and airway inflammation. aGR1 depleted granulocytes and CD8(+) lymphocytes, which resulted in a partial prevention in AHR but no decrease in airway inflammation. Depletion of Ly6G-positive granulocytes, i.e., both neutrophils and eosinophils, prevented AHR and lung epithelial damage and significantly reduced airway inflammation. Injection of aGR1 or 1A8 led to significantly changed cytokine release patterns in TDI-treated mice. Granulocytes, both neutrophils and eosinophils, are key cellular players in this model of chemical-induced asthma.

Genomic and genome-wide association of susceptibility to radiation-induced fibrotic lung disease in mice

Background and purposeTo identify genes which influence the fibrotic response to thoracic cavity radiotherapy, we combined a genome wide single nucleotide polymorphism (SNP) association evaluation of inbred strain response with prior linkage and gene expression data. Material and methodsMice were exposed to 18Gy whole thorax irradiation and survival, bronchoalveolar cell differential, and histological alveolitis and fibrosis phenotypes were determined. Association analyses were completed with 1.8 million SNPs in single markers and haplotypes. ResultsNine strains developed significant fibrosis and 11 strains succumbed to alveolitis only or alveolitis with minimal fibrosis. Post irradiation survival time (p<0.001) and bronchoalveolar lavage neutrophil percent (p=0.055) were correlated with extent of alveolitis and were not significantly correlated with fibrosis. Genome wide SNP analysis identified 10 loci as significantly associated with radiation-induced fibrotic lung disease (p<8.41×10−6; by permutation test), with the most significant SNP within a conserved non-coding region downstream of cell adhesion molecule 1 (Cadm1). Haplotype and SNP analyses performed within previously-identified loci revealed additional genes containing SNPs associated with fibrosis including Slamf6 and Cdkn1a. ConclusionCombining genomic approaches identified variation within specific genes which function in the tissue response to injury as associated with fibrosis following thoracic irradiation in mice.

Invasive adenocarcinoma with bronchoalveolar features: A population-based evaluation of the extent of resection in bronchoalveolar cell carcinoma

Invasive adenocarcinoma with bronchoalveolar features: A population-based evaluation of the extent of resection in bronchoalveolar cell carcinoma

Bronchoalveolar Lavage Results Are Independent of Season, Age, Gender and Collection Site

BackgroundClinical interpretation of bronchoalveolar lavage fluid results is dependent on the availability of reference values for healthy individuals. Only a few studies have published such reference values and the applicability of results is restricted by small sample sizes and the limited representativeness of the study population. We aim to investigate the influence of age, gender, collection site and season on bronchoalveolar lavage fluid results and to establish reference values for use in clinical practice.Methodology/Principal FindingsBronchoalveolar lavage fluid data from 295 healthy never-smoking volunteers, investigated during 1990–2009, were analyzed retrospectively. 47 volunteers had 2–5 repeat lavages during the course of several years. Fluid recovery, total number of cells, cell concentration, and differential cell counts on cytospin prepared slides were recorded. Reference values, as represented by the 5th to the 95th percentile, were 72–96% for macrophages, 2–26% for lymphocytes, 0–4% for neutrophils and 0–1% for eosinophils. Basophils and mast cells were rare. When repeat lavages were performed, there was a relatively large intra-individual variability, mainly for macrophages and lymphocytes. An age dependent decrease of lavage fluid return was present, but there was no age dependent correlation with any of the other BALF parameters. The BALF cell parameters were independent of gender, season and site (lingula vs. middle lobe).Conclusions/SignificanceOur data show that bronchoalveolar lavage fluid cell differential count is independent of age, gender, season and collection site (RML or lingua). It therefore seems acceptable to use the same reference values for all never-smoking individuals.

Skin TLR7 Triggering Promotes Accumulation of Respiratory Dendritic Cells and Natural Killer Cells

The TLR7 agonist imiquimod has been used successfully as adjuvant for skin treatment of virus-associated warts and basal cell carcinoma. The effects of skin TLR7 triggering on respiratory leukocyte populations are unknown. In a placebo-controlled experimental animal study we have used multicolour flow cytometry to systematically analyze the modulation of respiratory leukocyte subsets after skin administration of imiquimod. Compared to placebo, skin administration of imiquimod significantly increased respiratory dendritic cells (DC) and natural killer cells, whereas total respiratory leukocyte, alveolar macrophages, classical CD4+ T helper and CD8+ T killer cell numbers were not or only moderately affected. DC subpopulation analyses revealed that elevation of respiratory DC was caused by an increase of respiratory monocytic DC and CD11bhi DC subsets. Lymphocyte subpopulation analyses indicated a marked elevation of respiratory natural killer cells and a significant reduction of B lymphocytes. Analysis of cytokine responses of respiratory leukocytes after stimulation with Klebsiella pneumonia indicated reduced IFN-γ and TNF-α expression and increased IL-10 and IL-12p70 production after 7 day low dose skin TLR7 triggering. Additionally, respiratory NK cytotoxic activity was increased after 7d skin TLR7 triggering. In contrast, lung histology and bronchoalveolar cell counts were not affected suggesting that skin TLR7 stimulation modulated respiratory leukocyte composition without inducing overt pulmonary inflammation. These data suggest the possibility to modulate respiratory leukocyte composition and respiratory cytokine responses against pathogens like Klebsiella pneumonia through skin administration of a clinically approved TLR7 ligand. Skin administration of synthetic TLR7 ligands may represent a novel, noninvasive means to modulate respiratory immunity.

Pulmonary impact of N-acetylcysteine in a controlled hemorrhagic shock model in rats

BackgroundExperimental hemorrhagic shock (HS) is based on controlling bleeding and the treatment of fluid resuscitation to restore tissue oxygenation and perfusion. The HS could promote ischemia/reperfusion injury, which induces a general exacerbation of the inflammatory process, initially compromising the lungs. N-acetylcysteine (NAC), an antioxidant, may attenuate ischemia/reperfusion injury. This study evaluated the effect of NAC in association with fluid resuscitation on pulmonary injury in a controlled HS model in rats. MethodsMale Wistar rats were submitted to controlled HS (mean arterial pressure of 35 mm Hg for 60 min). Two groups were constituted according to resuscitation solution administered: RLG (Ringer’s lactate solution) and RLG+NAC (Ringer’s lactate in association with 150 mg/kg NAC. A control group was submitted to catheterization only. After 120 min of resuscitation, bronchoalveolar lavage was performed to assess intra-alveolar cell infiltration and pulmonary tissue was collected for assessment of malondialdehyde, interleukin 6, and interleukin 10 and histopathology. ResultsCompared with the RLG group, the RLG+NAC group showed lower bronchoalveolar lavage inflammatory cell numbers, lower interstitial inflammatory infiltration in pulmonary parenchyma, and lower malondialdehyde concentration. However, tissue cytokine (interleukin 6 and interleukin 10) expression levels were similar. ConclusionN-acetylcysteine was associated with fluid resuscitation–attenuated oxidative stress and inflammatory cell infiltration in pulmonary parenchyma. N-acetylcysteine did not modify cytokine expression.

Aerosolized delivery of oxime MMB-4 in combination with atropine sulfate protects against soman exposure in guinea pigs

We evaluated the efficacy of aerosolized acetylcholinesterase (AChE) reactivator oxime MMB-4 in combination with the anticholinergic atropine sulfate for protection against respiratory toxicity and lung injury following microinstillation inhalation exposure to nerve agent soman (GD) in guinea pigs. Anesthetized animals were exposed to GD (841 mg/m3, 1.2 LCt50) and treated with endotracheally aerosolized MMB-4 (50 µmol/kg) plus atropine sulfate (0.25 mg/kg) at 30 sec post-exposure. Treatment with MMB-4 plus atropine increased survival to 100% compared to 38% in animals exposed to GD. Decreases in the pulse rate and blood O2 saturation following exposure to GD returned to normal levels in the treatment group. The body-weight loss and lung edema was significantly reduced in the treatment group. Similarly, bronchoalveolar cell death was significantly reduced in the treatment group while GD-induced increase in total cell count was decreased consistently but was not significant. GD-induced increase in bronchoalveolar protein was diminished after treatment with MMB-4 plus atropine. Bronchoalveolar lavage AChE and BChE activity were significantly increased in animals treated with MMB-4 plus atropine at 24 h. Lung and diaphragm tissue also showed a significant increase in AChE activity in the treatment group. Treatment with MMB-4 plus atropine sulfate normalized various respiratory dynamics parameters including respiratory frequency, tidal volume, peak inspiratory and expiratory flow, time of inspiration and expiration, enhanced pause and pause post-exposure to GD. Collectively, these results suggest that aerosolization of MMB-4 plus atropine increased survival, decreased respiratory toxicity and lung injury following GD inhalation exposure.

Role of reactive nitrogen species (RNS) generated via inducible nitric oxide synthase in vesicant-induced lung injury and inflammation

Nitrogen mustard (NM) is a toxic vesicant known to damage the respiratory tract by alkylating proteins, lipids and nucleic acids and causing oxidative stress. Acute injury is associated with increased expression of inducible nitric oxide synthase (iNOS) in lung macrophages and epithelial cells. In these studies we analyzed the effects of inhibiting iNOS using aminoguanidine (AG) on NM-induced pulmonary toxicity. Male Wistar rats were treated IT with NM (0.125 mg/kg) or control. Animals were sacrificed 1–28 days later and lungs analyzed for markers of injury, oxidative stress and inflammation. Exposure of rats to NM resulted in progressive histopathological changes including perivascular and peribronchial edema, inflammatory cell infiltration, luminal and alveolar accumulation of debris and fibrin, bronchiolization of the alveolar septal wall, fibroplasia and fibrosis. This was correlated with increased bronchoalveolar lavage protein and inflammatory cell content. NM intoxication also resulted in increased expression of iNOS and COX-2, as well as HO-1 and Mn-SOD at all the post exposure times. Evidence of Type II cell proliferation, as well as YM1 and galectin-3 positive pro-fibrotic macrophages were also noted in the lung 3–28 days post NM exposure. Treatment of rats with AG (50 mg/kg, 2x/day for 3 days) abrogated acute injury, inflammation and oxidative stress induced by NM 1–3 days post exposure; with no effects at 7–28 days. These findings indicate that RNS generated via iNOS contribute to early events in NM-induced lung toxicity, however, transient inhibition of iNOS is not sufficient to protect against pulmonary fibrosis.

Critical role for integrin-β4 in the attenuation of murine acute lung injury by simvastatin

The statins are a class of 3-hydroxy-3-methylglutaryl-coenzyme A-reductase inhibitors that are recognized to have pleiotropic properties. We previously reported the attenuation of LPS-induced murine acute lung injury (ALI) by simvastatin in vivo and identified relevant effects of simvastatin on endothelial cell (EC) signaling, activation, and barrier function in vitro. In particular, simvastatin induces the upregulation of integrin-β4, which in turn inhibits EC inflammatory responses via attenuation of MAPK signaling. The role of integrin-β4 in murine ALI protection by simvastatin, however, is unknown. We initially confirmed a time- and dose-dependent effect of simvastatin on increased integrin-β4 mRNA expression in human lung EC with peak protein expression evident at 16 h. Subsequently, reciprocal immunoprecipitation demonstrated an attenuation of LPS-induced integrin-β4 tyrosine phosphorylation by simvastatin (5 μM, 16 h). Increased expression of EC inflammatory cytokines [IL-6, IL-8, monocyte chemoattractant protein (MCP)-1, regulated on activation normal T cell expressed and secreted (RANTES)] by LPS (500 ng/ml, 4 h) was also significantly attenuated by simvastatin pretreatment (5 μM, 16 h), but this effect was reversed by cotreatment with an integrin-β4-blocking antibody. Finally, although simvastatin (20 mg/kg) conferred significant protection in murine ALI as evidenced by decreased bronchoalveolar lavage fluid cell counts, protein, inflammatory cytokines (IL-6, IL-1β, MCP-1, RANTES), decreased Evans blue dye albumin extravasation in lung tissue, and changes on lung histology, these effects were reversed by the integrin-β4-blocking antibody (IV, 1 mg/kg, 2 h before LPS). These findings support integrin-β4 as an important mediator of ALI protection by simvastatin and implicate signaling by integrin-β4 as a novel therapeutic target in patients with ALI.

Skin triggering of TLR7 modulates respiratory dendritic cells and natural killer cells - identification of a novel mode for manipulation of respiratory leukocytes

Objective: Dendritic cell (DC) maturation and activation in situ is a critical element of successful DC vaccination protocols whereas suppression of functional DC activation represents an important step in the development of immunoregulatory cellular therapy protocols. The TLR7 agonist imiquimod has been used successfully as novel topical immune adjuvant but the systemic use has been limited due to significant toxicity. We hypothesized that skin application of a synthetic TLR7 ligand may represent a novel means to modulate respiratory leukocytes. Methods: In a placebo-controlled experimental animal study we have used 7-colour flow cytometry to systematically analyze the modulation of murine respiratory leukocyte subsets after skin administration of the synthetic TLR7 ligand imiquimod. Results: Compared to placebo, skin administration of imiquimod markedly increased respiratory dendritic cells and innate lymphocytes within 24h, whereas total respiratory leukocytes, alveolar macrophages, T helper and killer lymphocyte numbers were not affected or reduced. DC subpopulation analyses revealed that elevation of respiratory DC was related to an increase of monocytic DC (CD11c+CD11b+MHC-classIIdimSiglecFneg,CD45+). Lymphocyte subpopulation analyses indicated a marked elevation of respiratory natural killer cells and a reduction of B cells. In contrast, bronchoalveolar cell counts and histopathology were not affected suggesting that skin TLR7 stimulation markedly modulated respiratory leukocyte composition without inducing a respiratory inflammatory response. Conclusion: These data suggest for the first time the possibility to modulate respiratory leukocyte subsets after skin administration of a clinically approved TLR7 ligand. Skin administration of synthetic TLR7 ligands may represent a novel and safe means to modulate respiratory immunity. DC vaccination trials targeting the respiratory system may be modulated by skin TLR7 triggering.

Accuracy of FDG-PET to diagnose lung cancer in the ACOSOG Z4031 trial.

7008 Background: Fluoro-deoxyglucose positron emission tomography (FDG-PET) is recommended for diagnosis and staging of known or suspected NSCLC. Meta-analyses examining the accuracy of FDG-PET to diagnose lung cancer demonstrated high sensitivity 94% and specificity 83% but were performed in select centers. The purpose of this study is to evaluate the accuracy of FDG-PET to diagnose NSCLC and examine enrolling site differences in the national prospective ACOSOG Z4031 trial. Methods: 1,074 patients with clinical stage I (cT1-2N0M0) known or suspected NSCLC were enrolled between 2004 and 2006 in the Z4031 study and underwent surgical resection. The final diagnosis was determined by pathological examination. FDG-PET results were abstracted from radiology interpretations included in the case report forms. FDG-PET avidity was categorized based on either radiologist description or reported maximum standard uptake value (SUV). The four categories were: not avid and not cancerous (SUV=0), low avidity and likely not cancerous (SUV&gt;0 and &lt;2.5), avid and probably cancerous (SUV&gt;2.5 and &lt;5) and highly avid and likely cancerous (SUV&gt;5). Sensitivity analysis of FDG-PET diagnostic accuracy was performed for varying levels of avidity and by preoperative lesion size. Differences in accuracy by enrolling site were examined. Results: There were 51 enrolling sites in 39 cities with 969 eligible participants. Preoperative FDG-PET results were available for 682 participants. Lung cancer prevalence was 83%. FDG-PET sensitivity was 82% (95% CI: 79-85), and specificity was 31% (95% CI: 23-40). Positive and negative predictive values were 85% and 26%, respectively and accuracy improved with lesion size. There were 80 false positive scans and 69% were granulomas. False negative scans occurred in 101 patients (11were ≤10mm) with adenocarcinoma, squamous, bronchoalveolar cell and neuroendocrine tumors responsible for 64%, 12%, 10% and 8% of false negative results, respectively. Specificity did not differ between the 8 sites with &gt;25 patients (p=0.74). Conclusions: In a national surgical population with clinical stage I NSCLC, FDG-PET to diagnose lung cancer performed poorly compared to published studies. Reasons for poor test performance should be explored.

The value of positron emission tomography in early detection of lung cancer in high‐risk population: a systematic review

Early detection trials with chest radiography and sputum cytology were ineffective in decreasing lung cancer mortality. The advent of low-dose spiral chest computed tomography (LDCT) provided clinicians with a new tool that could be with early diagnosis; however, this also raised significant concerns regarding the systematic use of LDCT with its high false-positive rate for benign nodules. At this time, there is limited information about the true role of PET (positron emission tomography) for early detection of lung cancer. We used systematic methods, including Preferred Reporting Items for Systematic reviews and Meta-Analyses statement, to identify relevant studies, assess study eligibility, evaluate study methodological quality, and summarize findings regarding diagnostic accuracy and outcome. In total, only seven eligible studies were selected from 82 potentially relevant studies. The sensitivity of 18F-FDG-PET for the detection of T1 lung cancers ranged between 68% and 95%. The rate of detection tended to be lower for carcinoid tumors, adenocarcinoma and bronchoalveolar cell carcinomas. FDG-PET using SUV (standardized uptake value) level can predict the outcome of the screening detected lung cancer. A combination of FDG-PET and LDCT may improve screening for lung cancer in high-risk patients. PET or PET/CT may be used as a useful tool for early detection of lung cancer in high-risk population based on the existing information. However, there is still limited information with regards to evidence of survival benefits from PET screening in high-risk patients.

The CT halo sign: A rare manifestation of squamous cell carcinoma of the lung

At computed tomography (CT) the halo sign represents ground-glass attenuation surrounding a pulmonary nodule or mass on thin-section CT and is associated with a range of pathological entities. The sign is non-specific and the most common neoplastic cause is bronchoalveolar cell carcinoma.We report a raremanifestation of the halo sign due to a squamous cell carcinoma of the lung, and to the authors’ knowledge, this is the first case evolving from a non-solid (pure ground-glass) lesion.

Evidence for type II cells as cells of origin of K-Ras–induced distal lung adenocarcinoma

Identifying the cells of origin of lung cancer may lead to new therapeutic strategies. Previous work has focused upon the putative bronchoalveolar stem cell at the bronchioalveolar duct junction as a cancer cell of origin when a codon 12 K-Ras mutant is induced via adenoviral Cre inhalation. In the present study, we use two "knock-in" Cre-estrogen receptor alleles to inducibly express K-RasG12D in CC10(+) epithelial cells and Sftpc(+) type II alveolar cells of the adult mouse lung. Analysis of these mice identifies type II cells, Clara cells in the terminal bronchioles, and putative bronchoalveolar stem cells as cells of origin for K-Ras-induced lung hyperplasia. However, only type II cells appear to progress to adenocarcinoma.

Role of Sphingomyelin Synthesis in Pulmonary Endothelial Cell Cytoskeletal Activation and Endotoxin-Induced Lung Injury

Sphingomyelin (SM), a major sphingolipid in the lipid raft microdomains of the cell membrane, is synthesized by plasma membrane-bound sphingomyelin synthase 2 (SMS2). SMS2 is required for the maintenance of plasma membrane microdomain fluidity and receptor-mediated responses to inflammation in macrophages. However, the exact mechanism of SMS2 activation in endothelial barrier disruption and lung injury is not fully understood. To define the role of SMS activation in lung injury, we hypothesized that the inhibition of SM synthesis may provide protection against acute lung injury (ALI) by preserving endothelial barrier function. Using SMS2-silencing RNA (siRNA) treatment in human pulmonary endothelial cells (HPAECs) and tricyclodecan-9-yl-xanthogenate (D609), a competitive inhibitor of SMS, and phosphatidylcholine-specific phospholipase C in a murine model of bacterial LPS injury, we studied the role of sphingomyelin synthesis in ALI. Results show that pretreating mice with D609 significantly attenuated LPS-induced lung injury, as measured by a significant decrease in wet to dry ratio, bronchoalveolar lavage fluid cell and protein counts, and myeloperoxidase activity in lung tissue. Similarly, LPS-induced endothelial barrier disruption was significantly reduced in HPAECs pretreated with D609 or SMS2 siRNA, as demonstrated by an increase in paracellular integrity on an FITC-dextran assay, by the inhibition of LPS-induced stress fibers, and by the formation of cortical actin rings and lamellipodia at the periphery. These results indicate that D609 attenuates LPS-mediated endothelial barrier dysfunction and lung injury in mice through inhibition of SMS, suggesting a novel and essential role of SMS inhibition in modulating endothelial barrier integrity via actin cytoskeletal activation, with a potential therapeutic role in ALI.