Cerebral asymmetry in the control of cardiovascular functioning: evidence from lateral vibrotactile stimulation

Research has supported hemispheric specialisation in the regulation of cardiovascular functioning, with the left hemisphere being associated with parasympathetic functioning and the right hemisphere with sympathetic functioning. We sought to investigate this relationship further using vibrotactile stimulation applied to the palms. Our prediction was that vibrotactile stimulation applied to the left hand would result in increased heart rate and blood pressure, and that stimulation applied to the right hand would result in decreased heart rate and blood pressure. The results indicated significant differences in heart rate change scores in the predicted direction. No differences were noted for systolic or diastolic blood pressure. Hence the findings provide partial support for the lateralisation of autonomic functions.

Responses of airway epithelium to environmental injury: role in the induction phase of childhood asthma

The pathogenesis of allergic asthma in childhood remains poorly understood. Environmental factors which appear to contribute to allergic sensitisation, with development of a Th2-biased immunological response in genetically predisposed individuals, include wheezing lower respiratory viral infections in early life and exposure to airborne environmental pollutants. These may activate pattern recognition receptors and/or cause oxidant injury to airway epithelial cells (AECs). In turn, this may promote Th2 polarisation via a "final common pathway" involving interaction between AEC, dendritic cells, and CD4+ T lymphocytes. Potentially important cytokines produced by AEC include thymic stromal lymphopoietin and interleukin-25. Their role is supported by in vitro studies using human AEC, as well as by experiments in animal models. To date, however, few investigations have employed models of the induction phase of childhood asthma. Further research may help to identify interventions that could reduce the risk of allergic asthma.

Haemophilus influenzae infection drives IL-17-mediated neutrophilic allergic airways disease

A subset of patients with stable asthma has prominent neutrophilic and reduced eosinophilic inflammation, which is associated with attenuated airways hyper-responsiveness (AHR). Haemophilus influenzae has been isolated from the airways of neutrophilic asthmatics; however, the nature of the association between infection and the development of neutrophilic asthma is not understood. Our aim was to investigate the effects of H. influenzae respiratory infection on the development of hallmark features of asthma in a mouse model of allergic airways disease (AAD). BALB/c mice were intraperitoneally sensitized to ovalbumin (OVA) and intranasally challenged with OVA 12-15 days later to induce AAD. Mice were infected with non-typeable H. influenzae during or 10 days after sensitization, and the effects of infection on the development of key features of AAD were assessed on day 16. T-helper 17 cells were enumerated by fluorescent-activated cell sorting and depleted with anti-IL-17 neutralizing antibody. We show that infection in AAD significantly reduced eosinophilic inflammation, OVA-induced IL-5, IL-13 and IFN-γ responses and AHR; however, infection increased airway neutrophil influx in response to OVA challenge. Augmented neutrophilic inflammation correlated with increased IL-17 responses and IL-17 expressing macrophages and neutrophils (early, innate) and T lymphocytes (late, adaptive) in the lung. Significantly, depletion of IL-17 completely abrogated infection-induced neutrophilic inflammation during AAD. In conclusion, H. influenzae infection synergizes with AAD to induce Th17 immune responses that drive the development of neutrophilic and suppress eosinophilic inflammation during AAD. This results in a phenotype that is similar to neutrophilic asthma. Infection-induced neutrophilic inflammation in AAD is mediated by IL-17 responses.

Inhibition of house dust mite-induced allergic airways disease by antagonism of microRNA-145 is comparable to glucocorticoid treatment

BACKGROUND

Glucocorticoids are used as mainstay therapy for asthma, but some patients remain resistant to therapy. MicroRNAs (miRNAs) are important regulators of the immune system by promoting the catabolism of their target transcripts as well as attenuating their translation. The role of miRNA in regulating allergic inflammation remains largely unknown. Blocking miRNA function may provide a new nonsteroidal anti-inflammatory approach to treatment.

OBJECTIVES

To (1) determine the role of specific miRNAs in the regulation of hallmark features of allergic airways inflammation and (2) compare the efficacy of antagonizing miRNA function with that of steroid treatment.

METHODS

Mice were sensitized and then aeroallergen-challenged with house dust mite to induce allergic airways disease, and alterations in the expression of miRNAs were characterized. Next mice were treated with antagomirs that inhibited the function of specific miRNAs in the lung or treated with dexamethasone and inflammatory lesions, and airway hyperresponsiveness was measured.

RESULTS

miR-145, miR-21, and let-7b have been implicated in airway smooth muscle function, inflammation, and airways epithelial cell function, respectively. Inhibition of miR-145, but not miR-21 or lethal-7b, inhibited eosinophilic inflammation, mucus hypersecretion, T(H)2 cytokine production, and airway hyperresponsiveness. The anti-inflammatory effects of miR-145 antagonism were comparable to steroid treatment.

CONCLUSION

Our study highlights the importance of understanding the contribution of miRNAs to pathogenesis of human allergic disease and their potential as novel anti-inflammatory targets.

Altered expression of microRNA in the airway wall in chronic asthma: miR-126 as a potential therapeutic target

Background

The role of microRNAs (miRNAs) in regulating gene expression is currently an area of intense interest. Relatively little is known, however, about the role of miRNAs in inflammatory and immunologically-driven disorders. In a mouse model, we have previously shown that miRNAs are potentially important therapeutic targets in allergic asthma, because inhibition of miR-126, one of a small subset of miRNAs upregulated in the airway wall, effectively suppressed Th2-driven airway inflammation and other features of asthma. In the present study, we extended investigation of the therapeutic potential of miRNA inhibition to our well-established model of chronic asthma.

Methods

Female BALB/c mice were systemically sensitised with ovalbumin (OVA) and chronically challenged with low mass concentrations of aerosolised OVA for up to 6 weeks. Airway tissue was obtained by blunt dissection and RNA was isolated for miRNA profiling. On the basis of the results obtained, animals were subsequently treated with either an antagomir to miR-126 (ant-miR-126) or a scrambled control antagomir once weekly during the 6 weeks of chronic challenge, and the effects on airway inflammation and remodelling were assessed using established morphometric techniques.

Results

Compared to naïve mice, there was selective upregulation of a modest number of miRNAs, notably miR-126, in the airway wall tissue of chronically challenged animals. The relative increase was maximal after 2 weeks of inhalational challenge and subsequently declined to baseline levels. Compared to treatment with the scrambled control, ant-miR-126 significantly reduced recruitment of intraepithelial eosinophils, but had no effect on the chronic inflammatory response, or on changes of airway remodelling.

Conclusions

In this model of chronic asthma, there was an initial increase in expression of a small number of miRNAs in the airway wall, notably miR-126. However, this later declined to baseline levels, suggesting that sustained changes in miRNA may not be essential for perpetuation of chronic asthma. Moreover, inhibition of miR-126 by administration of an antagomir suppressed eosinophil recruitment into the airways but had no effect on chronic inflammation in the airway wall, or on changes of remodelling, suggesting that multiple miRNAs are likely to regulate the development of these lesions.

Plasmacytoid dendritic cells promote host defense against acute pneumovirus infection via the TLR7-MyD88-dependent signaling pathway

Human respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection in infants. In human infants, plasmacytoid dendritic cells (pDC) are recruited to the nasal compartment during infection and initiate host defense through the secretion of type I IFN, IL-12, and IL-6. However, RSV-infected pDC are refractory to TLR7-mediated activation. In this study, we used the rodent-specific pathogen, pneumonia virus of mice (PVM), to determine the contribution of pDC and TLR7 signaling to the development of the innate inflammatory and early adaptive immune response. In wild-type, but not TLR7- or MyD88-deficient mice, PVM inoculation led to a marked infiltration of pDC and increased expression of type I, II, and III IFNs. The delayed induction of IFNs in the absence of TLR7 or MyD88 was associated with a diminished innate inflammatory response and augmented virus recovery from lung tissue. In the absence of TLR7, PVM-specific CD8(+) T cell cytokine production was abrogated. The adoptive transfer of TLR7-sufficient, but not TLR7-deficient pDC to TLR7 gene-deleted mice recapitulated the antiviral responses observed in wild-type mice and promoted virus clearance. In summary, TLR7-mediated signaling by pDC is required for appropriate innate responses to acute pneumovirus infection. It is conceivable that as-yet-unidentified defects in the TLR7 signaling pathway may be associated with elevated levels of RSV-associated morbidity and mortality among otherwise healthy human infants.

Cytokine/anti-cytokine therapy - novel treatments for asthma?

Asthma is a chronic inflammatory disease of the airways and there are no preventions or cures. Inflammatory cells through the secretion of cytokines and pro-inflammatory molecules are thought to play a critical role in pathogenesis. Type 2 CD4(+) lymphocytes (Th2 cells) and their cytokines predominate in mild to moderate allergic asthma, whereas severe steroid-resistant asthma has more of a mixed Th2/Th1 phenotype with a Th17 component. Other immune cells, particularly neutrophils, macrophages and dendritic cells, as well structural cells such as epithelial and airway smooth muscle cells also produce disease-associated cytokines in asthma. Increased levels of these immune cells and cytokines have been identified in clinical samples and their potential role in disease demonstrated in studies using mouse models of asthma. Clinical trials with inhibitors of cytokines such as interleukin (IL)-4, -5 and tumour necrosis factor-α have had success in some studies but not others. This may reflect the design of the clinical trials, including treatments regimes and the patient population included in these studies. IL-13, -9 and granulocyte-macrophage colony-stimulating factor are currently being evaluated in clinical trials or preclinically and the outcome of these studies is eagerly awaited. Roles for IL-25, -33, thymic stromal lymphopoietin, interferon-γ, IL-17 and -27 in the regulation of asthma are just emerging, identifying new ways to treat inflammation. Careful interpretation of results from mouse studies will inform the development and application of therapeutic approaches for asthma. The most effective approaches may be combination therapies that suppress multiple cytokines and a range of redundant and disconnected pathways that separately contribute to asthma pathogenesis. Astute application of these approaches may eventually lead to the development of effective asthma therapeutics. Here we review the current state of knowledge in the field.

Interleukin-13 promotes susceptibility to chlamydial infection of the respiratory and genital tracts

Chlamydiae are intracellular bacteria that commonly cause infections of the respiratory and genital tracts, which are major clinical problems. Infections are also linked to the aetiology of diseases such as asthma, emphysema and heart disease. The clinical management of infection is problematic and antibiotic resistance is emerging. Increased understanding of immune processes that are involved in both clearance and immunopathology of chlamydial infection is critical for the development of improved treatment strategies. Here, we show that IL-13 was produced in the lungs of mice rapidly after Chlamydia muridarum (Cmu) infection and promoted susceptibility to infection. Wild-type (WT) mice had increased disease severity, bacterial load and associated inflammation compared to IL-13 deficient (-/-) mice as early as 3 days post infection (p.i.). Intratracheal instillation of IL-13 enhanced bacterial load in IL-13-/- mice. There were no differences in early IFN-g and IL-10 expression between WT and IL-13-/- mice and depletion of CD4+ T cells did not affect infection in IL-13-/- mice. Collectively, these data demonstrate a lack of CD4+ T cell involvement and a novel role for IL-13 in innate responses to infection. We also showed that IL-13 deficiency increased macrophage uptake of Cmu in vitro and in vivo. Moreover, the depletion of IL-13 during infection of lung epithelial cells in vitro decreased the percentage of infected cells and reduced bacterial growth. Our results suggest that enhanced IL-13 responses in the airways, such as that found in asthmatics, may promote susceptibility to chlamydial lung infection. Importantly the role of IL-13 in regulating infection was not limited to the lung as we showed that IL-13 also promoted susceptibility to Cmu genital tract infection. Collectively our findings demonstrate that innate IL-13 release promotes infection that results in enhanced inflammation and have broad implications for the treatment of chlamydial infections and IL-13-associated diseases.

Blocking induction of T helper type 2 responses prevents development of disease in a model of childhood asthma

Early-life respiratory viral infections are linked to subsequent development of allergic asthma in children. We assessed the underlying immunological mechanisms in a novel model of the induction phase of childhood asthma. BALB/c mice were infected neonatally with pneumonia virus of mice, then sensitized intranasally with ovalbumin following recovery. Animals were challenged with low levels of aerosolized ovalbumin for 4 weeks to induce changes of chronic asthma, then received a single moderate-level challenge to elicit mild acute allergic inflammation. To inhibit the initial induction of a T helper type 2 (Th2) response, we administered neutralizing antibodies against interleukin (IL)-4 or IL-25, then assessed development of airway inflammation and remodelling. Anti-IL-4 administered during chronic challenge prevented development of chronic and acute allergic inflammation, as well as goblet cell hyperplasia/metaplasia, but features of remodelling such as subepithelial fibrosis and epithelial hypertrophy were unaffected. In contrast, anti-IL-25 had limited effects on the airway inflammatory response but prevented key changes of remodelling, although it had no effect on goblet cells. Both antibodies suppressed development of a Th2 response, while anti-IL-25 also promoted a Th17 response. In further experiments, anti-IL-25 was administered in early life alone, and again had limited effects on airway inflammation, but prevented development of airway wall remodelling. We conclude that in this murine model of childhood asthma, administration of anti-IL-4 or anti-IL-25 prevents development of some key features of asthma, suggesting that suppression of development of a Th2 response during the neonatal period or later in childhood could be effective for primary prevention.

Use of palmitoylethanolamide in the entrapment neuropathy of the median in the wrist

AIM

Carpal tunnel syndrome (CTS) is a medical condition in which the median nerve is compressed, leading to discomfort and pain. Palmitoylethanolamide (PEA) is an endogenous fatty acid amide, able to modulate inflammatory cell reactivity and pain. This study deals with the capability of PEA to normalize the electroneurographic alterations associated with moderate CTS.

METHODS

Patients displaying moderate CTS were enrolled and daily PEA (600 mg or 1 200 mg/die) was administered for 30 days. Control group received no treatment.

RESULTS

PEA treatment significantly improved the CTS-induced reduction of median nerve latency time (P<0.0004); PEA effect was dose-dependent. Tinel's sign presence and symptoms of discomfort were also reduced.

CONCLUSION

Although further studies are needed to better characterize PEA effect, the present report represents the first evidence on the improvement of distal motor latency elicited by PEA in patients with moderate CTS. The data support the hypothesis of protection against inflammatory and neuropathic pain by PEA.

Anxiety and depression severity are related to right but not left onset Parkinson's disease duration

Depression and anxiety have both been associated with relative left frontal hypoactivation and the motor symptoms of Parkinson's disease typically begin in a lateral or asymmetrical fashion. Hence, PD patients with right hemibody onset may experience heightened depression and anxiety. However, research is mixed regarding whether right or left hemibody onset PD is associated with elevated levels of depression and anxiety. This literature, though, has not considered the potential moderating variable of disease duration. We hypothesized that disease duration would be positively correlated with measures of depression and anxiety in right but not left hemibody onset PD patients. The results indicated that scores on the Geriatric Depression Scale, Beck Depression Inventory-II, and the State Trait Anxiety Scale - State correlated positively with disease duration, but only in the right hemibody onset group of PD patients. Thus, right hemibody onset PD is associated with more severe depressive and anxiety symptoms, but only when disease duration is considered.

Lyprinol reduces inflammation and improves lung function in a mouse model of allergic airways disease

BACKGROUND

Asthma is an inflammatory airway disease that is characterized by an influx of eosinophils to the lungs, mucus hypersecretion and T helper type 2 cytokine production. Recent dietary changes, including a decreased ω-3 polyunsaturated fatty acid (PUFA) intake, may have contributed to increased asthma rates and dietary supplementation with marine oil could have clinical benefits.

OBJECTIVE

To assess the effects of dietary supplementation with ω-3 PUFAs on allergic inflammation and lung function using a mouse model of ovalbumin (OVA)-induced allergic airway disease (AAD).

METHODS

BALB/c mice received a daily supplement of either fish oil (rich in ω-3 PUFA) or lyprinol (a complex mixture of various marine lipids plus vitamin E and olive oil) before and during AAD. The effects of supplementation on AAD were assessed.

RESULTS

Lyprinol but not fish oil treatment reduced eosinophil influx into the bronchoalveolar lavage fluid, the lung tissue surrounding the airways and the blood, decreased mucus hypersecretion in the lung and reduced airway hyperresponsiveness (AHR). The effects of lyprinol were not associated with changes in serum IgG1 or IgG2a, or the release of IL-4, IL-5, IL-13 and IFN-γ.

CONCLUSIONS

Lyprinol suppresses the development of allergic inflammation and AHR in AAD. The therapeutic potential of dietary supplementation with lyprinol for asthma warrants further investigation.

Interleukin-13 (IL-13)/IL-13 receptor alpha1 (IL-13Ralpha1) signaling regulates intestinal epithelial cystic fibrosis transmembrane conductance regulator channel-dependent Cl- secretion

Interleukin-13 (IL-13) has been linked to the pathogenesis of inflammatory diseases of the gastrointestinal tract. It is postulated that IL-13 drives inflammatory lesions through the modulation of both hematopoietic and nonhematopoietic cell function in the intestine. To delineate the relevant contribution of elevated levels of intestinal IL-13 to intestinal structure and function, we generated an intestinal IL-13 transgenic mouse (iIL-13Tg). We show that constitutive overexpression of IL-13 in the small bowel induces modification of intestinal epithelial architecture (villus blunting, goblet cell hyperplasia, and increased epithelial proliferation) and epithelial function (altered basolateral → apical Cl(-) ion conductance). Pharmacological analyses in vitro and in vivo determined that elevated Cl(-) conductance is mediated by altered cystic fibrosis transmembrane conductance regulator expression and activity. Generation of iIL-13Tg/Il13rα1(-/-), iIL-13Tg/Il13rα2(-/-), and iIL-13Tg/Stat6(-/-) mice revealed that IL-13-mediated dysregulation of epithelial architecture and Cl(-) conductance is dependent on IL-13Rα1 and STAT-6. These observations demonstrate a central role for the IL-13/IL-13Rα1 pathway in the regulation of intestinal epithelial cell Cl(-) secretion via up-regulation of cystic fibrosis transmembrane conductance regulator, suggesting an important role for this pathway in secretory diarrhea.

Feeling down: idiom or nature?

Different emotions activate different parts of the brain, and different parts of the brain direct actions-intentions as well as attention (AIA) to different portions of space. This pilot study attempted to learn how different emotions elicited by emotional memories altered the voluntary spatial allocation of AIA. Twenty normal participants were asked to mark a large sheet of paper in any place of their choosing following recollection of seven types of emotional memories. The results suggest that different emotional memories-experiences can influence the spatial allocation of AIA with positive emotional memories inducing a distal or superior bias and sad memories inducing a proximal or inferior bias. Although these results support the hypotheses that emotions can influence the spatial direction of AIA, these preliminary results need replication and further exploration.

Pneumococcal conjugate vaccine-induced regulatory T cells suppress the development of allergic airways disease

BACKGROUND

Infections with some bacteria, including Streptococcus pneumoniae, have been associated with a reduced incidence of asthma. Components of S pneumoniae may have the potential to modulate allergic inflammatory responses and suppress the development of asthma.

OBJECTIVES

To determine if human S pneumoniae vaccines have the potential to suppress asthma by elucidating their effect on allergic airways disease (AAD) in mouse models.

METHODS

AAD was induced in BALB/c mice by intraperitoneal sensitisation and intranasal challenge with ovalbumin. Pneumococcal conjugate or polysaccharide vaccines were administered at the time of sensitisation or during established AAD. Hallmark features of AAD were assessed. Levels of regulatory T cells (Tregs) were quantified by fluorescence-activated cell sorting, and their immunoregulatory capacity was assessed using proliferation assays and anti-CD25 antibody treatment.

RESULTS

Intranasal administration of the conjugate vaccine, but not the polysaccharide vaccine, suppressed the hallmark features of AAD, including: eosinophilic and T helper 2-mediated inflammation; airway hyper-responsiveness; circulating immunoglobulin E (IgE) levels; and mucus hypersecretion. Intramuscular administration of the conjugate vaccine had limited protective effects. The conjugate vaccine increased Tregs in the lung-draining lymph nodes, lung and spleen. Furthermore, conjugate vaccine-induced Tregs had an enhanced capacity to suppress T effector responses. Anti-CD25 administration reversed the suppressive effects of the conjugate vaccine.

CONCLUSIONS

A currently available human conjugate vaccine suppresses the hallmark features of AAD through the induction of Tregs. Thus targeted administration may provide a novel immunoregulatory treatment for asthma.

Fibulin-1 is increased in asthma--a novel mediator of airway remodeling?

Background

The extracellular matrix is a dynamic and complex network of macromolecules responsible for maintaining and influencing cellular functions of the airway. The role of fibronectin, an extracellular matrix protein, is well documented in asthma. However, the expression and function of fibulin-1, a secreted glycoprotein which interacts with fibronectin, has not been reported. Fibulin-1 is widely expressed in basement membranes in many organs including the lung. There are four isoforms in humans (A–D) of which fibulin-1C and 1D predominate. The objective of this study was to study the expression of fibulin-1 in volunteers with and without asthma, and to examine its function in vitro.

Methodology/Principal Findings

We used immunohistochemistry and dot-blots to examine fibulin-1 levels in bronchial biopsies, bronchoalveolar lavage fluid and serum. Real-time PCR for fibulin-1C and 1D, and ELISA and western blotting for fibulin-1 were used to study the levels in airway smooth muscle cells. The function of fibulin-1C was determined by assessing its role, using an antisense oligonucleotide, in cell proliferation, migration and wound healing. A murine model of airway hyperresponsiveness (AHR) was used to explore the biological significance of fibulin-1. Levels of fibulin-1 were significantly increased in the serum and bronchoalveolar lavage fluid of 21 asthmatics compared with 11 healthy volunteers. In addition fibulin-1 was increased in asthma derived airway smooth muscle cells and fibulin-1C contributed to the enhanced proliferation and wound repair in these cells. These features were reversed when fibulin-1C was suppressed using an antisense oligomer. In a mouse model of AHR, treatment with an AO inhibited the development of AHR to methacholine.

Conclusions

Our data collectively suggest fibulin-1C may be worthy of further investigation as a target for airway remodeling in asthma.

Potential therapeutic targets for steroid-resistant asthma

Glucocorticoids are the mainstay of asthma management and effectively treat acute exacerbations of asthma. However, a small subset of asthmatics, usually with severe asthma, respond poorly even to systemic administration of high-dose glucocorticoids and this condition is termed "steroid-resistant asthma". This cohort, although small, accounts for approximately 50% of total health care cost for asthma. New investigations into the mechanisms of glucocorticoid action have broadened and deepened our understanding of glucocorticoid resistance. Here we review the importance and characteristics of steroid resistant asthma, the mechanisms that mediate the function of glucocorticoids and that lead to the development of this disease and potential therapies to reverse resistance to treatment. Cellular and molecular factors, receptors and complex signalling pathways have all been implicated. Indeed, based on molecular biological studies, excessive activation of intracellular transcription factors, impaired histone deacetylase, and epigenetic (such as miR-18 and miR-124a) as well as other factors (e.g. vitamin D, P-glycoprotein 170, and macrophage migration inhibitory factor and T helper 17 cells and factors related to innate immunity (such as IFN-gamma and LPS)) may result in glucocorticoid resistance. A thorough understanding of the pathogenesis of steroid resistant asthma will help to develop more efficacious agents for the treatment of the disease.

NK cell deficiency predisposes to viral-induced Th2-type allergic inflammation via epithelial-derived IL-25

Severe respiratory syncytial virus (RSV) infection has long been associated with an increased risk for the development of childhood asthma and exacerbations of this disorder. Despite much research into the induction of Th2 responses by allergens and helminths, the factors associated with viral infection that predispose to Th2-regulated asthma remain unknown. Recently, clinical studies have shown reduced numbers of NK cells in infants suffering from a severe RSV infection. Here we demonstrate that NK cell deficiency during primary RSV infection of BALB/c mice results in the suppression of IFN-γ production and the development of an RSV-specific Th2 response and subsequent allergic lung disease. The outgrowth of the Th2 responses was dependent on airway epithelial cell-derived IL-25, which induced the upregulation of the notch ligand Jagged1 on dendritic cells. This study identifies a novel pathway underlying viral-driven Th2 responses that may have functional relevance to viral-associated asthma.

IL-27/IFN-γ induce MyD88-dependent steroid-resistant airway hyperresponsiveness by inhibiting glucocorticoid signaling in macrophages

Inflammation and airway hyperresponsiveness (AHR) are hallmark features of asthma and often correlate with the severity of clinical disease. Although these features of asthma can be effectively managed with glucocorticoid therapy, a subgroup of patients, typically with severe asthma, remains refractory to therapy. The mechanisms leading to steroid resistance in severe asthmatics are poorly understood but may be related to the activation of innate host defense pathways. Previously, we have shown that IFN-γ-producing cells and LPS, two factors that are associated with severe asthma, induce steroid-resistant AHR in a mouse model. We now demonstrate that cooperative signaling induced by IFN-γ and LPS results in the production of IL-27 by mouse pulmonary macrophages. IL-27 and IFN-γ uniquely cooperate to induce glucocorticoid-resistant AHR through a previously unknown MyD88-dependent mechanism in pulmonary macrophages. Importantly, integrated signaling by IL-27/IFN-γ inhibits glucocorticoid-induced translocation of the glucocorticoid receptor to the nucleus of macrophages. Furthermore, expression of both IL-27 and IFN-γ was increased in the induced sputum of steroid-refractory asthmatics. These results suggest that a potential mechanism for steroid resistance in asthma is the activation of MyD88-dependent pathways in macrophages that are triggered by IL-27 and IFN-γ, and that manipulation of these pathways may be a therapeutic target.

Observation of a long-wavelength hosing modulation of a high-intensity laser pulse in underdense plasma

We report the first experimental observation of a long-wavelength hosing modulation of a high-intensity laser pulse. Side-view images of the scattered optical radiation at the fundamental wavelength of the laser reveal a transverse oscillation of the laser pulse during its propagation through underdense plasma. The wavelength of the oscillation λ(hosing) depends on the background plasma density n(e) and scales as λ(hosing)∼n(e)(-3/2). Comparisons with an analytical model and two-dimensional particle-in-cell simulations reveal that this laser hosing can be induced by a spatiotemporal asymmetry of the intensity distribution in the laser focus which can be caused by a misalignment of the parabolic focusing mirror or of the diffraction gratings in the pulse compressor.

Emotional indifference in Alzheimer's disease

One of the most common and disabling symptoms of Alzheimer's disease is apathy. Patients with Alzheimer's disease might appear apathetic for several reasons, including deficits in emotional communication, presence of depression, perceptual-semantic-cognitive deficits, and a degeneration of areas of the brain important in experiencing emotions. The purpose of this study was to learn if patients with Alzheimer's disease have a reduction in the depth of their emotional experiences. Participants with Alzheimer's disease and healthy comparison subjects were asked to view pleasant and unpleasant pictures and to rate these pictures by making a mark on pieces of paper that had a happy face on one end (proximal or distal) and a sad face at the other end. The more pleasant they found this picture, the closer their mark should be to the happy face and vice versa. Patients with Alzheimer's disease judged these pictures' emotional valence as less intense than did the comparison subjects and also made more valence-inconsistent responses. These results might have been induced by impaired picture comprehension or a reduction of emotional experiences induced by degeneration of the limbic-cortical-reticular networks.

Alveolar macrophages stimulate enhanced cytokine production by pulmonary CD4+ T-lymphocytes in an exacerbation of murine chronic asthma

The mechanisms underlying the exaggerated distal airway inflammation and hyperresponsiveness that characterize acute exacerbations of asthma are largely unknown. Using BALB/c mouse experimental models, we demonstrated a potentially important role for alveolar macrophages (AM) in the development of an allergen-induced exacerbation of asthma. To induce features of airway inflammation and remodeling characteristic of mild chronic asthma, animals were systemically sensitized and exposed to low mass concentrations (≈3 mg/m(3)) of aerosolized ovalbumin for 30 minutes per day, 3 days per week, for 4 weeks. A subsequent single moderate-level challenge (≈30 mg/m(3)) was used to trigger an acute exacerbation. In chronically challenged animals, cytokine expression by AM was not increased, whereas after an acute exacerbation, AM exhibited significantly enhanced expression of proinflammatory cytokines, including interleukin (IL) 1β, IL-6, CXCL-1, and tumor necrosis factor α. In parallel, there was a marked increase in the expression of several cytokines by CD4(+) T-lymphocytes, notably the Th2 cytokines IL-4 and IL-13. Importantly, AM from an acute exacerbation stimulated the expression of Th2 cytokines when cocultured with CD4(+) cells from chronically challenged animals, and their ability to do so was significantly greater than AM from either chronically challenged or naïve controls. Stimulation was partly dependent on interactions involving CD80/86. We conclude that in an acute exacerbation of asthma, enhanced cytokine expression by AM may play a critical role in triggering increased expression of cytokines by pulmonary CD4(+) T-lymphocytes.