Citations

We present the first evidence that adhesion mediated by a member of the cadherin gene family can be regulated by a G protein-coupled receptor. We show that activating the M3 muscarinic acetylcholine receptor (mAChR) rapidly induces E-cadherin-mediated adhesion in a small cell lung carcinoma (SCLC) cell line. This response is inhibited by E-cadherin antibodies, and does not occur in another SCLC cell line which expresses functional mAChR but reduced levels of E-cadherin. Protein kinase C may be involved, since phorbol 12-myristate 13-acetate also induces E-cadherin-mediated aggregation. Immunofluorescence analyses indicate that mAChR activation does not grossly alter E-cadherin surface expression or localization at areas of cell-cell contact, suggesting mAChR activation may increase E-cadherin binding activity. Our findings suggest that G protein-coupled receptors may regulate processes involving cadherin-mediated adhesion, such as embryonic development, neurogenesis, and cancer metastasis.

AbstractEosinophil degranulation is thought to play a pivotal role in the pathogenesis of allergic disorders. Although mouse models of allergic disorders have been used extensively to identify the contribution of eosinophils to disease, ultrastructural evidence of active granule disassembly has not been reported. In this investigation, we characterized the degree of eosinophil activation in the bone marrow, blood, lung tissue, and airways lumen [bronchoalveolar lavage fluid (BALF)] of ovalbumin-sensitized and aero-challenged wild-type and interleukin-5 transgenic mice. Degranulation was most prominent in and primarily compartmentalized to the airways lumen. Eosinophils released granule proteins by the process of piecemeal degranulation (PMD). Accordingly, recruitment and activation of eosinophils in the lung correlated with the detection of cell-free eosinophil peroxidase in BALF and with the induction of airways hyper-reactivity. As in previous studies with human eosinophils, degranulation of isolated mouse cells did not occur until after adherence to extracellular matrix. However, higher concentrations of exogenous stimuli appear to be required to trigger adherence and degranulation (piecemeal) of mouse eosinophils when compared with values reported for studies of human eosinophils. Thus, mouse eosinophils undergo PMD during allergic inflammation, and in turn, this process may contribute to pathogenesis. However, the degranulation process in the allergic lung of mice is primarily compartmentalized to the airway lumen. Understanding the mechanism of eosinophil degranulation in the airway lumen may provide important insights into how this process occurs in human respiratory diseases.

Background— β-Blockers improve survival and reduce hospitalization in chronic heart failure (CHF) by biologically improving left ventricular ejection fraction (LVEF). However, a good predictor of improvement with this therapy has not been identified. This substudy of BEST examined whether myocardial contractile reserve, as determined by dobutamine stress echocardiography, predicts improvement in LVEF. Methods and Results— Seventy-nine patients with class III/IV CHF underwent dobutamine stress echocardiography before treatment with bucindolol (n=41) or placebo (n=38). Regional wall motion score index (WMSI) was calculated as the sum of the scores in each segment divided by the total number of segments visualized. WMSI was compared with change in LVEF after 3 months of therapy as determined by gated radionuclide scan. Change in WMSI correlated inversely with change in LVEF after 3 months of bucindolol ( r =−0.72, P <0.0001) and was the most significant multivariate predictor of change in LVEF ( P =0.0002). Patients with contractile reserve had demographics similar to those of patients without contractile reserve, including RVEF, LVEF, systolic blood pressure, and CHF duration. However, patients without contractile reserve had higher baseline plasma norepinephrine levels (687±333 versus 420±246 pg/mL, P <0.05) and greater decrease in plasma norepinephrine in response to bucindolol (−249±171 versus −35±277 pg/mL, P <0.05). Conclusions— This study suggests a direct relationship between contractile reserve and improvement in LVEF with β-blocker therapy in patients with advanced CHF. Patients without contractile reserve have higher resting adrenergic drive, as reflected by plasma norepinephrine, and may experience greater sympatholytic effects from bucindolol.

ABSTRACT Pneumocystis carinii causes severe pneumonia in immunocompromised hosts. The binding of P. carinii to alveolar epithelial cells and extracellular matrix constituents such as fibronectin and vitronectin is a central feature of infection, which initiates proliferation of the organism. Herein, we demonstrate that P. carinii binding to lung cells specifically alters the gene expression of the organism, regulating fungal growth. Subtractive hybridization was performed to isolate P. carinii genes expressed following binding to mammalian extracellular matrix constituents. P. carinii STE20 ( PCSTE20 ), a gene participating in mating and pseudohyphal growth of other fungi, was identified following adherence to the extracellular matrix constituents fibronectin, vitronectin, collagen, and lung epithelial cells. The expression of PCSTE20 and a related P. carinii mitogen-activated protein kinase (MAPK) kinase gene, also implicated in signaling of mating, were both specifically upregulated by binding to matrix protein. The expression of general cyclin-dependent kinases and other MAPKs not involved in mating pathways were not altered by organism binding. PCSTE20 expression was also strongly enhanced following organism attachment to A549 lung epithelial cells. When expressed in a Saccharomyces cerevisiae ste20Δ mutant, PCSTE20 suppressed defects in both mating and pseudohyphal growth. These findings are consistent with the observed proliferation and filopodial extension of Pneumocystis organisms adherent to the epithelium in the lungs of immunocompromised hosts. PCSTE20 expression appears to represent a significant component in the regulation of the life cycle of this intractable opportunistic pathogen.

Purpose: The North Central Cancer Treatment Group performed a phase III trial to determine whether chemotherapy plus either bid radiation therapy (RT) or daily (qd) RT resulted in a better outcome for patients with stage III non–small-cell lung cancer (NSCLC). No difference in survival was identified between the two arms. This secondary analysis was performed to examine the relationship between patient age and outcome. Patients and Methods: Two hundred forty-six patients were randomized to receive etoposide plus cisplatin and either RT qd or split-course RT bid. This retrospective study compared the outcomes of patients aged ≥70 years (“elderly patients”) with those of younger individuals. Of the 244 assessable patients, 63 (26%) were elderly, and 181 (74%) were younger individuals. Results: The 2-year and 5-year survival rates were 39% and 18%, respectively, in patients younger than 70 years, compared with 36% and 13%, respectively, in elderly patients (P = .4). Grade 4+ toxicity occurred in 62% of patients younger than 70 years compared with 81% of elderly patients (P = .007). Grade 4+ hematologic toxicity occurred in 56% of patients younger than 70 years, compared with 78% of elderly patients (P = .003). Grade 4+ pneumonitis occurred in 1% of those younger than 70 years, compared with 6% of elderly patients (P = .02). Conclusion: Toxicity, especially myelosuppression and pneumonitis, was more pronounced in the elderly patients receiving combined-modality therapy for locally advanced NSCLC. Despite increased toxicity, elderly patients have survival rates equivalent to younger individuals. Therefore, fit, elderly patients with locally advanced NSCLC should be encouraged to receive combined-modality therapy, preferably on clinical trials with cautious, judicious monitoring. Future studies should explore ways to decrease toxicity of therapy in elderly patients.

Background— Stroke, mainly attributable to atherothrombotic disease, represents a leading cause of disability and death in the Western world. Endothelial dysfunction, which is considered a key factor in atherogenesis, is associated with an increased risk of cardiovascular events. However, the magnitude of the association between coronary endothelial dysfunction (CED) and cerebrovascular events is unknown. This study was performed to investigate the association between CED and cerebrovascular events. Methods and Results— We studied 503 patients without obstructive coronary artery disease (CAD) who underwent coronary endothelial function testing by intracoronary acetylcholine infusion. Patients were divided according to the presence (n=305) or absence (n=198) of CED, and medical records were examined for the occurrence of ischemic or hemorrhagic stroke or transient ischemic attack either before (prevalent) or after (incident) coronary endothelial function testing. Among the study population, a total of 25 cerebrovascular events were documented, 22 in patients with CED (15 prevalent) and 3 in patients without (all prevalent) ( P =0.008). Multivariable logistic regression, which included traditional cerebrovascular disease–related risk factors, identified the presence of CED as the single strongest factor associated with cerebrovascular events (OR, 4.32; 95% CI, 1.26 to 14.83). Kaplan-Meier analysis indicated that patients with CED had a significantly higher cumulative cerebrovascular event rate than those without ( P =0.04). Conclusions— Presence of CED in patients without obstructive CAD is independently associated with an increased risk of cerebrovascular events. Thus, detection of this early stage of atherosclerosis may provide important information to identify patients who benefit from aggressive preventive strategies.

Purpose: This phase II study was undertaken to define the efficacy and pharmacodynamics of R115777, a farnesyl transferase inhibitor, in the first-line treatment of patients with advanced non–small-cell lung cancer. Patients and Methods: Forty-four patients with measurable stage IIIB (pleural effusion) or stage IV disease received 193 courses of treatment (median, 2.0; range, 1 to 22) with R115777 300 mg administered orally twice daily for 21 of every 28 days. Buccal mucosa samples and peripheral blood mononuclear cells (PBMCs) were collected before and after 8 days of treatment to evaluate inhibition of farnesyl transferase in vivo. Results: No objective complete or partial responses were documented. Seven patients (16%; 95% confidence interval [CI], 8% to 31%) had disease stabilization for greater than 6 months. Median survival was 7.7 months (95% CI, 6.5 to 10.5) and time to progression was 2.7 months (95% CI, 1.9 to 3.1). The most severe toxicity was neutropenia (9% grade 3, 7% grade 4) and the most common toxicities were anemia (50% grade 1 or 2, 5% grade 3) and anorexia (50% grade 1 or 2, 2% grade 3). Mild peripheral neuropathy occurred in 25% of patients. Evidence of farnesyl transferase inhibition was documented in 83% of patients. Conclusion: Single-agent R115777 was well tolerated in patients with advanced NSCLC, but demonstrated minimal clinical activity. Inhibition of farnesylation in vivo was consistently documented. On the basis of promising results of farnesyl transferase inhibitor combinations with standard chemotherapy agents, future studies of this agent in NSCLC should be in combination with systemic chemotherapy.

Abstract We tested the hypothesis that cells of ventilator-injured lungs are subject to reversible plasma membrane stress failure. Rat lungs were perfused with the membrane impermeable fluorescent marker propidium iodide and randomized to one of four ventilation strategies. Subpleural lung regions were imaged with confocal microscopy, and cell injury was quantified as the number of propidium iodide–positive cells per alveolus. The number of injured cells was significantly greater in lungs ventilated with large tidal volumes and zero end-expiratory pressure than in lungs ventilated with small tidal volumes and positive end-expiratory pressure (p &lt; 0.01). Cell injury correlated with lung weight gain, change in dynamic compliance, and histologic injury scores. In a second set of experiments, lungs were mechanically ventilated for 30 minutes at high tidal volume settings, whereas propidium iodide was perfused either during or after injurious ventilation. Labeling after removal of injurious stress revealed significantly fewer injured cells (0.25 ± 0.09 to 0.08 ± 0.08, p &lt; 0.01). We conclude that cells of ventilator-injured lungs are subject to reversible plasma membrane stress failure.

Abstract Acute lung injury (ALI) and its more severe form, the acute respiratory distress syndrome (ARDS), are syndromes of acute respiratory failure that result from acute pulmonary edema and inflammation. The development of ALI/ARDS is associated with several clinical disorders including direct pulmonary injury from pneumonia and aspiration as well as indirect pulmonary injury from trauma, sepsis, and other disorders such as acute pancreatitis and drug overdose. Although mortality from ALI/ARDS has decreased in the last decade, it remains high. Despite two major advances in treatment, low VT ventilation for ALI/ARDS and activated protein C for severe sepsis (the leading cause of ALI/ARDS), additional research is needed to develop specific treatments and improve understanding of the pathogenesis of these syndromes. The NHLBI convened a working group to develop specific recommendations for future ALI/ARDS research. Improved understanding of disease heterogeneity through use of evolving biologic, genomic, and genetic approaches should provide major new insights into pathogenesis of ALI. Cellular and molecular methods combined with animal and clinical studies should lead to further progress in the detection and treatment of this complex disease.

We describe a 63-year-old smoker who suffered from intractable facial pain secondary to an underlying lung neoplasm. Data from 30 previously reported and similar cases are also summarized. The clinical triad of a smoker suffering from periauricular pain and an elevated ESR should alert the clinician to the possibility of an occult lung mass. In these cases a computed tomography of the chest should always be obtained. Previously refractory pain typically responds to surgical resection of the mass and/or radiation therapy.