Assessment of Left Lung Remodeling With Magnetic Resonance Imaging in a Murine Model Following Exposure to Douglas Fir Smoke

Wildland firefighters (WLFFs) experience lung function decline due to occupational exposure to fire smoke. WLFFs typically do not wear respiratory personal protective equipment, and if they do, it is a simple bandana, which is not effective at filtering smoke. To pinpoint the biological underpinnings of abnormal respiratory function following 3-7 years of WLFF service, we exposed mice to Douglas fir smoke (DFS) over 8 weeks. Following exposure, we assessed changes in lung structure through Magnetic Resonance Imaging (MRI) and histological analysis, which was supported by immunohistochemistry staining. With MRI, we found that the signal decay time, T2*, from ultrashort echo time (UTE) images was significantly shorter in mice exposed to DFS compared to air controls. In addition, the variation in T2* was more heterogeneously distributed throughout the left lung in DFS-exposed mice, compared to air controls. As confirmed by histological analysis, shorter T2* was caused by larger parenchyma airspace sizes and not fibrotic remodeling. Destruction of the alveolar spaces was likely due to inflammation, as measured by an influx of CD68+ macrophages and destruction due to enhanced neutrophil elastase. In addition, measurements of airspace dimensions from histology were more heterogeneously distributed throughout the lung, corroborating the enhanced relative dispersion of T2*. Findings from this study suggest that the decline in lung function observed in WLFFs may be due to emphysema-like changes in the lung, which can be quantified with MRI.

Short-course subcutaneous treatment with PQ Grass strongly improves symptom and medication scores in grass allergy

BACKGROUND

A modified grass allergen subcutaneous immunotherapy (SCIT) product with MicroCrystalline Tyrosine and monophosphoryl lipid-A as an adjuvant system (Grass MATA MPL [PQ Grass]) is being developed as short-course treatment of grass-pollen allergic rhinitis (SAR) and/or rhinoconjunctivitis. We sought to evaluate the combined symptom and medication score (CSMS) of the optimized cumulative dose of 27,600 standardized units (SU) PQ Grass in a field setting prior to embarking on a pivotal Phase III trial.

METHODS

In this exploratory, randomized, double-blind, placebo-controlled trial subjects were enrolled across 14 sites (Germany and the United States of America). Six pre-seasonal subcutaneous injections of PQ Grass (using conventional or extended regimens) or placebo were administered to 119 subjects (aged 18-65 years) with moderate-to-severe SAR with or without asthma that was well-controlled. The primary efficacy endpoint was CSMS during peak grass pollen season (GPS). Secondary endpoints included Rhinoconjunctivitis Quality of Life Questionnaire standardized (RQLQ-S) and allergen-specific IgG4 response.

RESULTS

The mean CSMS compared to placebo was 33.1% (p = .0325) and 39.5% (p = .0112) for the conventional and extended regimens, respectively. An increase in IgG4 was shown for both regimens (p < .01) as well as an improvement in total RQLQ-S for the extended regimen (mean change -0.72, p = .02). Both regimens were well-tolerated.

CONCLUSIONS

This trial demonstrated a clinically relevant and statistically significant efficacy response to PQ Grass. Unprecedented effect sizes were reached for grass allergy of up to ≈40% compared to placebo for CSMS after only six PQ Grass injections. Both PQ Grass regimens were considered equally safe and well-tolerated. Based on enhanced efficacy profile extended regime will be progressed to the pivotal Phase III trial.

Prolonged smoldering Douglas fir smoke inhalation augments respiratory resistances, stiffens the aorta, and curbs ejection fraction in hypercholesterolemic mice

While mounting evidence suggests that wildland fire smoke (WFS) inhalation may increase the burden of cardiopulmonary disease, the occupational risk of repeated exposure during wildland firefighting remains unknown. To address this concern, we evaluated the cardiopulmonary function in mice following a cumulative exposure to lab-scale WFS equivalent to a mid-length wildland firefighter (WLFF) career. Dosimetry analysis indicated that 80 exposure hours at a particulate concentration of 22 mg/m3 yield in mice the same cumulative deposited mass per unit of lung surface area as 3600 h of wildland firefighting. To satisfy this condition, male Apoe-/- mice were whole-body exposed to either air or smoldering Douglas fir smoke (DFS) for 2 h/day, 5 days/week, over 8 consecutive weeks. Particulate size in DFS fell within the respirable range for both mice and humans, with a count median diameter of 110 ± 20 nm. Expiratory breath hold in mice exposed to DFS significantly reduced their minute volume (DFS: 27 ± 4; Air: 122 ± 8 mL/min). By the end of the exposure time frame, mice in the DFS group exhibited a thicker (DFS: 109 ± 3; Air: 98 ± 3 μm) and less distensible (DFS: 23 ± 1; Air: 28 ± 1 MPa-1) aorta with reduced diastolic blood augmentation capacity (DFS: 53 ± 2; Air: 63 ± 2 kPa). Cardiac magnetic resonance imaging further revealed larger end-systolic volume (DFS: 14.6 ± 1.1; Air: 9.9 ± 0.9 μL) and reduced ejection-fraction (DFS: 64.7 ± 1.0; Air: 75.3 ± 0.9 %) in mice exposed to DFS. Consistent with increased airway epithelium thickness (DFS: 10.4 ± 0.8; Air: 7.6 ± 0.3 μm), airway Newtonian resistance was larger following DFS exposure (DFS: 0.23 ± 0.03; Air: 0.20 ± 0.03 cmH2O-s/mL). Furthermore, parenchyma mean linear intercept (DFS: 36.3 ± 0.8; Air: 33.3 ± 0.8 μm) and tissue thickness (DFS: 10.1 ± 0.5; Air: 7.4 ± 0.7 μm) were larger in DFS mice. Collectively, mice exposed to DFS manifested early signs of cardiopulmonary dysfunction aligned with self-reported events in mid-career WLFFs.

Respiratory mechanics following chronic cigarette smoke exposure in the Apoe[Formula: see text] mouse model

Even though cigarette smoking (CS) has been on the decline over the past 50 years, it is still the leading cause of preventable premature death in the United States. Preclinical models have investigated the cardiopulmonary effects of CS exposure (CSE), but the structure-function relationship in the respiratory system has not yet been fully explored. To evaluate these relationships, we exposed female apolipoprotein E-deficient (Apoe[Formula: see text]) mice to mainstream CS ([Formula: see text]) for 5 days/week over 24 weeks with room air as a control (AE, [Formula: see text]). To contextualize the impact of CSE, we also assessed the natural aging effects over 24 weeks of air exposure (baseline, [Formula: see text]). Functional assessments were performed on a small animal mechanical ventilator (flexiVent, SCIREQ), where pressure-volume curves and impedance data at four levels of positive end-expiratory pressure ([Formula: see text]) and with increasing doses of methacholine were collected. Constant phase model parameters ([Formula: see text]: Newtonian resistance, H: coefficient of tissue elastance, and G: coefficient of tissue resistance) were calculated from the impedance data. Perfusion fixed-left lung tissue was utilized for quantification of parenchyma airspace size and tissue thickness, airway wall thickness, and measurements of elastin, cytoplasm + nucleus, fibrin, and collagen content for the parenchyma and airways. Aging caused the lung to become more compliant, with an upward-leftward shift of the pressure-volume curve and a reduction in all constant phase model parameters. This was supported by larger parenchyma airspace sizes, with a reduction in cell cytoplasm + nucleus area. Airway walls became thinner, even though low-density collagen content increased. In contrast, CSE caused a downward-rightward shift of the pressure-volume curve along with an increase in H, G, and hysteresivity ([Formula: see text]). Organ stiffening was accompanied by enhanced airway hyper-responsiveness following methacholine challenge. Structurally, parenchyma airspaces enlarged, as indicated by an increase in equivalent airspace diameter ([Formula: see text]), and the septum thickened with significant deposition of low-density collagen along with an influx of cells. Airway walls thickened due to deposition of both high and low-density collagen, infiltration of cells, and epithelial cell elongation. In all, our data suggest that CSE in female Apoe[Formula: see text] mice reduces respiratory functionality and causes morphological alterations in both central and peripheral airways that results in lung stiffening, compared to AE controls.

Pharmacological and physiological response in Apoe-/- mice exposed to cigarette smoke or e-cigarette aerosols

OBJECTIVE

Electronic cigarettes (e-cigs) are popular nicotine delivery devices, yet the health effects remain unclear. To determine equivalent biomarkers, we characterized the immediate response in Apoe^-/- mice exposed to tank/box-mod e-cig (e-cig_tank), pod e-cig (e-cig_pod), or cig smoke.

MATERIALS AND METHODS

Reproducible puff profiles were generated for each aerosol and delivered to Apoe^-/- mice via a nose-only exposure system. Serum cotinine levels were quantified at various time points through ELISA and utilized to model cotinine pharmacokinetics. In addition, particle size measurements and mouse respiratory function were characterized to calculate particle dosimetry.

RESULTS AND DISCUSSION

Cig and e-cig_tank particles were lognormally distributed with similar count median diameters (cig: 178 ± 2, e-cig_tank: 200 ± 34nm), while e-cig_pod particles were bimodally distributed and smaller (116 ± 13 and 13.3 ± 0.4 nm). Minute volumes decreased with cig exposure (5.4 ± 2.7 mL/min) compared to baseline (90.8 ± 11.6 mL/min), and less so with e-cig_tank (45.2 ± 9.2 mL/min) and e-cig_pod exposures (58.6 ± 6.8 mL/min), due to periods of apnea in the cig exposed groups. Cotinine was absorbed and eliminated most rapidly in the e-cig_pod group (tmax = 14.5; t1/2' = 51.9 min), whereas cotinine was absorbed (cig: 50.4, e-cig_tank: 40.1 min) and eliminated (cig: 104.6, e-cig_tank: 94.1 min) similarly in the cig and e-cig_tank groups. For exposure times which equate the area under the cotinine-concentration curve, ∼6.4× (e-cig_tank) and 4.6× (e-cig_pod) more nicotine deposited in e-cig compared to cig exposed mice.

CONCLUSIONS

This study provides a basis for incorporating cotinine pharmacokinetics into preclinical exposure studies, allowing for longitudinal studies of structural and functional changes due to exposure.

Effect of moisture content and fuel type on emissions from vegetation using a steady state combustion apparatus

Emission measurements are available in the literature for a wide variety of field burns and laboratory experiments, although previous studies do not always isolate the effect of individual features such as fuel moisture content (FMC). This study explores the effect of FMC on gaseous and particulate emissions from flaming and smouldering combustion of four different wildland fuels found across the United States. A custom linear tube-heater apparatus was built to steadily produce emissions in different combustion modes over a wide range of FMC. Results showed that when compared with flaming combustion, smouldering combustion showed increased emissions of CO, particulate matter and unburned hydrocarbons, corroborating trends in the literature. CO and particulate matter emissions in the flaming mode were also significantly correlated with FMC, which had little influence on emissions for smouldering mode combustion, when taking into account the dry mass of fuel burned. These variations occurred for some vegetative fuel species but not others, indicating that the type of fuel plays an important role. This may be due to the chemical makeup of moist and recently live fuels, which is discussed and compared with previous measurements in the literature.

Simulated Wildfire Smoke Significantly Alters Sperm DNA Methylation Patterns in a Murine Model

Wildfires are now a common feature of the western US, increasing in both intensity and number of acres burned over the last three decades. The effects of this changing wildfire and smoke landscape are a critical public and occupational health issue. While respiratory morbidity due to smoke exposure is a priority, evaluating the molecular underpinnings that explain recent extrapulmonary observations is necessary. Here, we use an Apoe-/- mouse model to investigate the epigenetic impact of paternal exposure to simulated wildfire smoke. We demonstrate that 40 days of exposure to smoke from Douglas fir needles induces sperm DNA methylation changes in adult mice. DNA methylation was measured by reduced representation bisulfite sequencing and varied significantly in 3353 differentially methylated regions, which were subsequently annotated to 2117 genes. The differentially methylated regions were broadly distributed across the mouse genome, but the vast majority (nearly 80%) were hypermethylated. Pathway analyses, using gene-derived and differentially methylated region-derived gene ontology terms, point to a number of developmental processes that may warrant future investigation. Overall, this study of simulated wildfire smoke exposure suggests paternal reproductive risks are possible with prolonged exposure.

Structural and functional remodeling of the female Apoe-/- mouse aorta due to chronic cigarette smoke exposure

Despite a decline in popularity over the past several decades, cigarette smoking remains a leading cause of cardiovascular morbidity and mortality. Yet, the effects of cigarette smoking on vascular structure and function are largely unknown. To evaluate changes in the mechanical properties of the aorta that occur with chronic smoking, we exposed female apolipoprotein E-deficient mice to mainstream cigarette smoke daily for 24 wk, with room air as control. By the time of euthanasia, cigarette-exposed mice had lower body mass but experienced larger systolic/diastolic blood pressure when compared with controls. Smoking was associated with significant wall thickening, reduced axial stretch, and circumferential material softening of the aorta. Although this contributed to maintaining intrinsic tissue stiffness at control levels despite larger pressure loads, the structural stiffness became significantly larger. Furthermore, the aorta from cigarette-exposed mice exhibited decreased ability to store elastic energy and augment diastolic blood flow. Histological analysis revealed a region-dependent increase in the cross-sectional area due to smoking. Increased smooth muscle and extracellular matrix content led to medial thickening in the ascending aorta, whereas collagen deposition increased the thickness of the descending thoracic and abdominal aorta. Atherosclerotic lesions were larger in exposed vessels and featured a necrotic core overlaid by a thinned fibrous cap and macrophage infiltration, consistent with a vulnerable phenotype. Collectively, our data indicate that cigarette smoking decreases the mechanical functionality of the aorta, inflicts morphometric alterations to distinct segments of the aorta, and accelerates the progression of atherosclerosis.NEW & NOTEWORTHY We studied the effects of chronic cigarette smoking on the structure and function of the aorta in a mouse model of nose-only aerosol inhalation. Our data indicated that exposure to cigarette smoke impairs vascular function by reducing the ability of the aorta to store elastic energy and by decreasing aortic distensibility. Combined with a more vulnerable atherosclerotic phenotype, these findings reveal the biomechanical mechanisms that support the development of cardiovascular disease due to cigarette smoking.

Fully automated cardiac assessment for diagnostic and prognostic stratification following myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiovascular magnetic resonance (CMR) imaging is considered the reference methodology for cardiac morphology and function but requires manual post-processing. Whether novel artificial intelligence (AI) -based automated analyses deliver similar information for risk stratification is unknown. Therefore, this study aimed to investigate feasibility and prognostic implications of AI-based analyses.

Methods

CMR data (n = 1017 patients) from two myocardial infarction multi-center trials were included. Analyses of biventricular parameters including ejection fraction (EF) were manually and automatically assessed using conventional and AI-based software. Obtained parameters entered regression analyses for prediction of major adverse clinical events (MACE) defined as death, reinfarction or congestive heart failure within one-year after the acute event.

Results

Both manual and uncorrected automated volumetric assessments showed similar impact on outcome on univariate (LVEF HR 0.93, [95% CI 0.91-0.95]; p &lt; 0.001 for manual and HR 0.94 [0.92-0.96]; p &lt; 0.001 for automated) and multivariable analyses (LVEF HR 0.95, [0.92-0.98]; p = 0.001 for manual and HR 0.95 [CI 0.92-0.98]; p = 0.001 for automated). Manual correction of the automated contours did not lead to improved risk prediction (LVEF AUC 0.67 automated vs. 0.68 automated corrected, p = 0.49). There was acceptable agreement (bias: 2.6%, 95% limits of agreement [LOA] -9.1-14.2%, intraclass correlation coefficient [ICC] 0.88 [0.77-0.93] for LVEF) of manual and automated volumetric assessments.

Conclusions

User independent volumetric analyses performed by fully automated software are feasible and results are equally predictive of MACE compared with conventional analyses in patients following myocardial infarction.

Frequency and prognostic impact of right ventricular involvement in acute myocardial infarction

Background

Right ventricular (RV) involvement complicating myocardial infarction (MI) is thought to impact prognosis, but potent RV markers for risk stratification are lacking.

Purpose

To assess the frequency and prognostic implications of concomitant structural and functional RV injury in MI.

Methods

Cardiac magnetic resonance (CMR) was performed in 1235 patients with MI (STEMI: n=795; NSTEMI: n=440) 3 days after reperfusion by primary percutaneous coronary intervention. Central core laboratory-masked analyses included structural (edema representing reversible ischemia, irreversible infarction, microvascular obstruction [MVO]) and functional (ejection fraction, global longitudinal strain [GLS]) RV alterations. The clinical endpoint was the 12-month rate of major adverse cardiac events (MACE).

Results

RV ischemia and infarction were observed in 19.6% and 12.1% of patients, respectively, suggesting complete myocardial salvage in one-third of patients. RV ischemia was associated with a significantly increased risk of MACE (10.1% versus 6.2%; p=0.035), while patients with RV infarction showed only numerically increased event rates (p=0.075). RV MVO was observed in 2.4% and not linked to outcome (p=0.894). Stratification according to median RV GLS (10.2% versus 3.8%; p&lt;0.001) but not RV ejection fraction (p=0.175) resulted in elevated MACE rates. Multivariable analysis including clinical and left ventricular MI characteristics identified RV GLS as an independent predictor of outcome (hazard ratio 1.05, 95% confidence interval 1.00–1.09; p=0.034) in addition to age (p=0.001), Killip class (p=0.020), and left ventricular GLS (p=0.001), while RV ischemia was not independently associated with outcome.

Conclusions

RV GLS is a predictor of post-infarction adverse events over and above established risk factors, while structural RV involvement was not independently associated with outcome.

Funding Acknowledgement

Type of funding source: None

Covariate analysis of QTc and T-wave morphology: new possibilities in the evaluation of drugs that affect cardiac repolarization

This study adds the dimension of a T-wave morphology composite score (MCS) to the QTc interval-based evaluation of drugs that affect cardiac repolarization. Electrocardiographic recordings from 62 subjects on placebo and 400 mg moxifloxacin were compared with those from 21 subjects on 160 and 320 mg D,L-sotalol. T-wave morphology changes, as assessed by DeltaMCS, are larger after 320 mg D,L-sotalol than after 160 mg D,L-sotalol; and the changes associated with 160 mg D,L-sotalol are, in turn, larger than those associated with moxifloxacin and placebo. Covariate analyses of DeltaQTc and DeltaMCS showed that changes in T-wave morphology are a significant effect of D,L-sotalol. By contrast, moxifloxacin was found to have no significant effect on T-wave morphology (DeltaMCS) at any given change in QTc. This study offers new insights into the repolarization behavior of a drug associated with low cardiac risk vs. one associated with a high risk and describes the added benefits of a T-wave MCS as a covariate to the assessment of the QTc interval.

Neurocognition and its influencing factors in the treatment of schizophrenia-effects of aripiprazole, olanzapine, quetiapine and risperidone

BACKGROUND

To examine influencing variables of neurocognition in patients with schizophrenia and to predict cognition during antipsychotic treatment.

METHODS

Data were obtained from patients with an acute episode of schizophrenia participating in two double-blind and one open label trial comparing the effects of different atypical antipsychotics on cognition. In total, 129 patients were enrolled in this analysis. Cognitive function was assessed at admission, week 4 and 8. Efficacy and tolerability were assessed weekly using the Positive and Negative Syndrome Scale (PANSS) and the Simpson Angus Sale (SAS). Patients were treated with aripirazole, olanzapine, quetiapine and risperidone. Regression analysis including mixed effect models was performed.

RESULTS

A significant improvement in all cognitive domains was observed from baseline to week 8. Regarding the antipsychotic treatment applied quetiapine seemed to achieve the most favourable cognitive improvement. Negative and depressive symptoms, the patient's age and the concomitant and antipsychotic treatment applied were observed to significantly influence and predict neurocognition.

CONCLUSION

The results may indicate that schizophrenia is a static disorder with trait and state dependent cognitive components especially in the memory domains. The influence of negative and depressive symptoms should be considered in daily clinical routine.

Effect of aripiprazole on cognition in the treatment of patients with schizophrenia

BACKGROUND

The aim of this study was to assess the cognitive effects of aripiprazole in inpatients with schizophrenia.

METHODS

This was an investigator-initiated, open label eight-week trial evaluating 56 inpatients with the DSM-IV diagnosis of schizophrenia. Efficacy was assessed weekly using the Positive and Negative Syndrome Scale (PANSS) and tolerability was assessed each week using the Udvalg for Klinske Undersogelser side effect rating scale (UKU). Cognitive function was assessed at baseline, week 4 and week 8.

RESULTS

Aripiprazole showed significant improvement in PANSS total score and all subscores between baseline and endpoint visit. The substance was very well tolerated. Patients improved significantly in verbal memory, reaction time and reaction quality/attention from baseline to week eight. Furthermore, mean z-values of individual cognitive domains summarized in a global cognitive index improved significantly from baseline to week eight.

DISCUSSION

Our results suggest that aripiprazole provides a valuable treatment option for patients with schizophrenia.

Orthostatic hypotensive effect of antipsychotic drugs in Wistar rats by in vivo and in vitro studies of alpha1-adrenoceptor function

RATIONALE

Many antipsychotics cause orthostatic hypotension possibly due to antagonist action on resistance vessel alpha1A-adrenoceptors (alpha1A-AR).

OBJECTIVE

We have tested this possibility by determining in Wistar rats how the orthostatic hypotensive effect of several antipsychotic drugs compares with their affinity for adrenoceptors in mesenteric small arteries (MSA with mainly alpha1A-AR) and aorta (mainly alpha1D-AR).

MATERIALS AND METHODS

Using a tilt setup, orthostatic hypotension was measured in anaesthetized rats for prazosin and the antipsychotics haloperidol, sertindole, risperidone, clozapine, ziprasidone, domperidone, olanzapine, and aripiprazole. For in vitro studies, segments of MSA and aorta were mounted on a wire myograph for isometric tension recording. Cumulative concentration-response curves were constructed to phenylephrine (PE) in the absence and presence of the drugs. Apparent affinity (pA2) was calculated by Schild analysis.

RESULTS

Prazosin antagonized tilt-induced and PE responses in both studies (threshold 4 ng/ml, pA2 9.52 MSA, 10.1 aorta). The rank order of the potency of the antipsychotics in the tilt experiments correlated (r2 = 0.69, P = 0.01) with the pA2-values in MSA: Risperidone and sertindole had the highest potency in the tilt test (threshold 159 and 97 ng/ml) and the highest apparent affinity in MSA (pA2 8.92 and 8.78), in contrast with aripiprazole and domperidone, which had the lowest in each case (threshold 4.1 and 3.0 microg/ml, pA2 7.17 and 6.99). In aorta, the pA2 values did not correlate with the in vivo potencies; in particular, sertindole had no functional affinity in aorta.

CONCLUSION

We conclude that the orthostatic hypotensive effect in rats of the antipsychotic drugs investigated is mediated through alpha1A-ARs.

Omalizumab provides long-term control in patients with moderate-to-severe allergic asthma

The ability of omalizumab, an anti-immnoglobulin-E agent, to maintain long-term disease control in patients with moderate-to-severe allergic asthma was investigated in a 24-week double-blind extension to a 28-week core trial. During the extension, 483 of the initial 546 patients were maintained on randomised treatment and the lowest sustainable dose of beclomethasone dipropionate (BDP) as established during the steroid-reduction phase of the core trial. The use of concomitant asthma medication was permitted and investigators were allowed to adjust the BDP dose or switch patients from BDP to other asthma medications if deemed necessary. More omalizumab-treated patients (33.5%) than placebo-treated patients (13.5%) were able to complete the extension period without requiring inhaled corticosteroid treatment. The mean BDP equivalent dose throughout the extension was lower in the omalizumab group (25 microg x day(-1)) than in the placebo group (43 microg x day(-1)). Disease control was sustained in 76% of omalizumab patients compared with 59.4% of placebo patients free from an asthma exacerbation during the extension period. Compared with placebo, fewer patients in the omalizumab group used other concomitant asthma medication during the extension. Treatment with omalizumab was well tolerated and the incidence of adverse events was similar between groups. In conclusion, these results suggest that omalizumab is a promising new agent for the long-term control of allergic asthma.

Sertindole: cardiac electrophysiological profile

QT interval prolongation is the ECG correlate of prolongation of the cardiac action potential (AP). Abnormal or excessive QT interval prolongation may be associated with an increased risk of ventricular tachycardia. This association appears increasingly evident in congenital long QT syndrome and with certain classes of cardiovascular and non-cardiovascular therapeutics. Almost all drugs causing QT interval prolongation inhibit the rapid component of the delayed rectifier potassium current (I Kr ), an ion channel involved in the termination of the myocardial AP. Inhibition of I Kr leads to AP and QT interval prolongation. Drugs, which do not encounter a sufficient electrophysiological counterbalance to the inhibitory effect on I Kr , may thus impose a risk of ventricular tachyarrhythmia. Some non-cardiac drugs, including the antipsychotic sertindole, have inhibitory effects on I Kr but, in contrast to the drugs that are known to cause tachyarrhythmia, sertindole possesses an important electrophysiological counterbalancing profile. Sertindole inhibits &#102 1 -adrenoceptors and blocks both sodium and calcium channels. The balanced electrophysiological profile of sertindole may well explain the low proarrhythmic potential observed in animal proarrhythmia models against positive comparators. It also supports the lack of increased cardiac mortality observed in clinical trials with sertindole and in large epidemiological studies.

The anti-IgE antibody omalizumab reduces exacerbations and steroid requirement in allergic asthmatics

The clinical benefit and steroid-sparing effect of treatment with the anti-immunoglobulin-E (IgE) antibody, omalizumab, was assessed in patients with moderate-to-severe allergic asthma. After a run-in period, 546 allergic asthmatics (aged 12-76 yrs), symptomatic despite inhaled corticosteroids (500-1,200 microg daily of beclomethasone dipropionate), were randomized to receive double-blind either placebo or omalizumab every 2 or 4 weeks (depending on body weight and serum total IgE) subcutaneously for 7 months. A constant beclomethasone dose was maintained during a 16-week stable-steroid phase and progressively reduced to the lowest dose required for asthma control over the following 8 weeks. The latter dose was maintained for the next 4 weeks. Asthma exacerbations represented the primary variable. Compared to the placebo group, the omalizumab group showed 58% fewer exacerbations per patient during the stable-steroid phase (p<0.001). During the steroid-reduction phase, there were 52% fewer exacerbations in the omalizumab group versus the placebo group (p<0.001) despite the greater reduction of the beclomethasone dosage on omalizumab (p<0.001). Treatment with omalizumab was well tolerated. The incidence of adverse events was similar in both groups. These results indicate that omalizumab therapy safely improves asthma control in allergic asthmatics who remain symptomatic despite regular use of inhaled corticosteroids and simultaneous reduction in corticosteroid requirement.

Long-term asthma control with oral montelukast and inhaled beclomethasone for adults and children 6 years and older

BACKGROUND

Leukotriene receptor antagonists have demonstrated clinical benefits in chronic asthma studies of up to 3 months in duration. The effects of these agents over extended periods of time have not been reported.

OBJECTIVE

To describe the long-term effect of oral montelukast, a potent and specific cysteinyl leukotriene receptor antagonist, compared with inhaled corticosteroids in both adult and paediatric patients with chronic asthma.

METHODS

Male and female patients with chronic, stable asthma (adults aged 15-85 years, children aged 6-14 years), who had completed double-blind, placebo-controlled clinical studies, participated in three extension studies with oral montelukast taken once daily (10 mg tablet for adults, 5 mg chewable tablet for paediatric patients) or inhaled corticosteroids (beclomethasone 200 microg twice daily for adults, beclomethasone 100 microg or equivalent three times daily for children). A double-blind adult extension study was 37 weeks in duration; open-label adult extension studies were 156 (adults) and 112 (paediatric) weeks in duration. A total of 436, 374, and 245 patients entered these extension studies, respectively.

RESULTS

Treatment with both montelukast and inhaled corticosteroids resulted in improvement in multiple parameters of asthma control. Improvements in daytime symptom scores were generally comparable among treatment groups. No tachyphylaxis to the effects of montelukast was evident. In the adult open-label study, however, the effect of beclomethasone on mean forced expiratory volume in 1 second (FEV1) gradually decreased from start of the study to the end of the follow-up treatment period.

CONCLUSION

Both montelukast and inhaled corticosteroids were effective in controlling mild to moderate chronic asthma; the relative effectiveness of montelukast and beclomethasone were similar in open-label conditions. The hypothesis, that clinical practice conditions (e.g., adherence) may have a significant impact on the effectiveness of these therapies, should be tested in future clinical trials.

Characteristics of the pulse waveform during altered nitric oxide synthesis in the rabbit

Nitrovasodilators produce characteristic changes in the shape of the peripheral pulse wave. Similar changes might also be caused by alteration of endogenous NO activity, which would allow such activity to be assessed in vivo. We investigated whether manipulation of the NO pathway influences the pulse waveform, and the mechanisms involved. The pulse wave in the ear of normal rabbits was examined by reflectance photoplethysmography before and during infusion of vasoactive agents. Pulse wave velocity was assessed by using an additional sensor on the rear foot. A diastolic peak was observed in the ear pulse; its timing was consistent with it being a reflection of the systolic peak from the lower body. The height of the dicrotic notch marking the start of this diastolic wave was decreased by acetylcholine or an NO donor, and further decreased by a phosphodiesterase type V inhibitor. The acetylcholine-induced decreases were blocked by inhibiting NO synthesis with N(G)-nitro-L-arginine methyl ester (L-NAME) but were unaffected by the inactive enantiomer D-NAME. These data demonstrate that NO influences the height of the notch in the pulse wave. Heart rate and blood pressure were altered during acetylcholine or L-NAME infusion, but there were no changes in pulse wave amplitude or velocity, or in the timing of the diastolic peak or dicrotic notch. The slope of the pulse wave between the systolic peak and notch changed substantially. These effects are most convincingly explained by changes in wave reflection, not only from the lower body but also from more proximal sites.

Addition of salmeterol to low-dose fluticasone versus higher-dose fluticasone: an analysis of asthma exacerbations

BACKGROUND

Adding salmeterol to low-dose fluticasone propionate (FP) produces greater improvements in pulmonary function and symptom control than increasing the dose of FP in patients who remain symptomatic with low-dose FP.

OBJECTIVE

We sought to compare the rates and characteristics of asthma exacerbations in patients after adding salmeterol to low-dose FP with the rates and characteristics of exacerbations in patients receiving higher dose FP.

METHODS

In 2 multicenter, double-blind studies, 925 patients 12 years of age and older receiving 88 microg twice daily FP randomly received either 42 microg of salmeterol and 88 microg of FP or an increased dose of FP (220 microg) twice daily for 24 weeks. Exacerbation rates and clinical measures of asthma worsening were assessed for all patients who experienced an asthma exacerbation.

RESULTS

The addition of salmeterol resulted in a significantly lower rate and number of exacerbations compared with higher dose FP. A total of 41 (8.8%) patients experienced 47 exacerbations with the addition of salmeterol compared with 63 (13.8%) patients with 75 exacerbations in the group receiving increased-dose FP (P =.017). Salmeterol plus low-dose FP was significantly more protective than increased-dose FP in preventing asthma exacerbations, as assessed by the time to first exacerbation (P <.05). In both groups clinical indicators of worsening asthma showed parallel changes before asthma exacerbation, and greater improvements were observed after exacerbation with salmeterol compared with higher dose FP.

CONCLUSION

Salmeterol plus low-dose FP was more effective than higher dose FP alone in reducing asthma exacerbations in patients with persistent asthma. The ability to detect deteriorating asthma and the severity of exacerbation was similar between groups.

In vivo muscarinic cholinergic mediated effects of Lu 25-109, a M1 agonist and M2/M3 antagonist in vitro

Lu 25-109 [5-(2-ethyl-2H-tetrazol-5-yl)-1,2,3,6-tetrahydro-1-methylpyridine] , has M agonistic and M2/M3 antagonistic effects at muscarinic receptors in vitro; a pharmacological profile that may be beneficial in treatment of Alzheimer's disease. In the present study, we compare functional in vivo effects of Lu 25-109 and reference compounds in animal models of muscarinic cholinergic function. Lu 25-109 substituted completely for the discriminative stimulus effects of (-)-7-methyl-3-(2-propynyloxy)-4,5,6,7-tetrahydroisothiazolo -[4, 5-c]pyridine (Lu 26-046), a partial M1/M2 agonist, but only weakly for the effects of the non-selective M1/M2/M3 agonist 3-methoxy-4,5,6,7-tetrahydro-isoxazolo[4, 5-c] pyridine (O-Me-THPO). Lu 25-109 did not reverse O-Me-THPO-induced discriminative stimulus. Tacrine did not substitute for any of the training drugs. Lu 25-109 did not substitute in (-)-nicotine trained rats. Lu 25-109 did not antagonize oxotremorine-induced hypothermia, tremor and salivation in mice and antagonized physostigmine-induced lethality with low potency. Unlike non-selective muscarinic agonists and acetylcholinesterase inhibitors, Lu 25-109 did not induce hypothermia, tremor or salivation in mice. Spontaneous locomotor activity and motor co-ordination were inhibited only at high doses. Lu 25-109 had no effect on mean blood pressure in anaesthetized rats. Lu 25-109 and O-Me-THPO produced a significant increase in heart rate. The maximum increase was 37%. In anaesthetized cats, increasing i.v. doses of Lu 25-109 were without effect on the mean blood pressure, except for a short lasting (<2 min) depressor effect following the IV injection. Furthermore, Lu 25-109 did not attenuate the reflex mechanisms restoring blood pressure following orthostasis in cats. In conclusion, the drug discrimination studies suggest a unique activity profile of Lu 25-109, and the in vivo profile suggests none or a very low frequency of unwanted cholinergic mediated effects.

Montelukast for chronic asthma in 6- to 14-year-old children: a randomized, double-blind trial. Pediatric Montelukast Study Group

CONTEXT

Leukotrienes are important mediators of asthma by causing bronchoconstriction, mucous secretion, and increased vascular permeability. Studies using compounds that block leukotrienes have demonstrated improvement in asthma control in adults and adolescents, but children younger than 12 years, for whom asthma is the most common chronic disease, have not been studied.

OBJECTIVE

To determine the clinical effect of montelukast, a leukotriene receptor antagonist, in 6- to 14-year-old children with asthma.

DESIGN

Eight-week, multicenter, randomized, double-blind study.

SETTING

Forty-seven outpatient centers at private practices and academic medical centers in the United States and Canada.

PATIENTS

A total of 336 children with forced expiratory volume in 1 second (FEV1) between 50% to 85% of the predicted value, at least 15% reversibility after inhaled beta-agonist administration, a minimal predefined level of daytime asthma symptoms, and daily beta-agonist use. Concomitant inhaled corticosteroids at a constant daily dose were used by 39% of patients receiving montelukast and 33% receiving placebo.

INTERVENTION

After a 2-week placebo run-in period, patients received either montelukast (5-mg chewable tablet) or matching-image placebo once daily at bed-time for 8 weeks.

MAIN OUTCOME MEASURE

Morning FEV1 percent change from baseline.

RESULTS

Mean morning FEV1 increased from 1.85 L to 2.01 L in the montelukast group and from 1.85 L to 1.93 L in the placebo group. This represents an 8.23% (95% confidence interval [CI], 6.33% to 10.13%) increase from baseline in the montelukast group and a 3.58% (95% CI, 1.29% to 5.87%) increase from baseline in the placebo group (P<.001 for montelukast vs placebo).

CONCLUSION

Montelukast improves morning FEV1 in 6- to 14-year-old children with chronic asthma.

Investigation of endogenous nitric oxide vascular function in the carotid artery of cholesterol-fed rabbits

1. The function of endogenous nitric oxide (NO) at the level of vascular smooth muscle, was assessed in a popular experimental model of accelerated atherosclerosis, the cholesterol-fed rabbit. 2. Endothelium-dependent vasorelaxation in response to acetylcholine (ACh, 1 microM) was significantly impaired in the carotid artery from rabbits maintained on a 1% (W/W) cholesterol diet for 8-10 weeks. Furthermore, the ability of an inhibitor of nitric oxide synthase (NOS), NG-nitro-L-arginine methyl ester (L-NAME, 1-300 microM), to enhance the contractile reactivity to a submaximal concentration of noradrenaline (NA, 3 microM), was significantly attenuated in hypercholesterolaemia. 3. A significant linear correlation between the maximal contractile effect of L-NAME (300 microM) and maximal vasorelaxation to ACh (1 microM) was determined in the carotid artery from control rabbits. In contrast, no such linear correlation was found in the carotid artery from hypercholesterolaemic rabbits. 4. We conclude that there are lesions both in agonist-stimulated, endogenous NO-dependent vasorelaxation and in the regulation of vasoconstrictor reactivity by endogenous NO in the hypercholesterolaemic rabbit carotid artery. Furthermore, the normal linear relationship between the contractile effect of L-NAME and vasorelaxation to ACh is lost after cholesterol-feeding.

Vitamin E reverses cholesterol-induced endothelial dysfunction in the rabbit coronary circulation

Hypercholesterolaemia and atherosclerosis are associated with impaired endothelium-dependent vasodilation. In this study we have examined the effects of vitamin E on cholesterol-induced endothelial dysfunction in the rabbit coronary circulation. Rabbits were maintained for 4 or 8 weeks on one of three experimental diets: (a) control chow, (b) 1% cholesterol or (c) 1% cholesterol for the first half of the treatment period followed by 1% cholesterol + 0.2% vitamin E during the last half of the treatment. After sacrifice, vasodilator responses to acetylcholine and sodium nitroprusside in the isolated perfused heart were studied. Responses to sodium nitroprusside were similar between the groups whereas responses to acetylcholine were significantly impaired in cholesterol-fed rabbits after both 4 and 8 weeks when compared to controls. In the cholesterol + vitamin E group, responses to acetylcholine were similar to controls and significantly greater than in the group receiving cholesterol alone. These results show that both 4 and 8 weeks of cholesterol-feeding induces an endothelial dysfunction in the coronary circulation of the rabbit, and that vitamin E protects against this dysfunction. By comparing responses to acetylcholine in the 4 week cholesterol group with the 8 week cholesterol + vitamin E group it was shown that vitamin E may not only prevent further deterioration of the endothelial function in the rabbit heart, but may also reverse the adverse effects of hypercholesterolaemia.

Dietary vitamin E increases the resistance to lipoprotein oxidation and attenuates endothelial dysfunction in the cholesterol-fed rabbit

This study was conducted to determine if vitamin E could reverse or attenuate endothelial dysfunction following an atherogenic diet. Rabbits were initially fed 1% cholesterol for 4 weeks to induce endothelial dysfunction. During the next 4 weeks the rabbits were fed either 1% cholesterol +0.2% vitamin E or 1% cholesterol alone, and were then killed. Endothelium-dependent responses to acetylcholine, calcium ionophore A23187 and sodium nitroprusside (SNP) were studied in the preconstricted perfused rabbit ear. Dietary vitamin E partially reversed the impaired endothelium-dependent responses to acetylcholine associated with cholesterol feeding. The maximum decrease in perfusion pressure in response to acetylcholine was 77.8% +/- 3.6% in control animals, 35.3% +/- 2.6% in cholesterol-fed animals, and 49.1% +/- 4.7% in cholesterol+vitamin E treated animals. The response to A23187 or sodium nitroprusside did not differ between the groups. The susceptibility of rabbit beta-VLDL to oxidation was markedly decreased in the vitamin E treated animals as assessed by the formation of conjugated dienes. The formation of lipid peroxidation products were also significantly inhibited by vitamin E. These data suggest that dietary vitamin E is beneficial in reducing the oxidative injury that may lead to the impairment of nitric oxide (NO)-mediated responses in early hypercholesterolaemia.

Vitamin E restores endothelium dependent vasodilatation in cholesterol fed rabbits: in vivo measurements by photoplethysmography

OBJECTIVE

Pulse curve plethysmography was used to examine the effect of vitamin E on endothelium dependent and independent vasodilatation in unanaesthetised cholesterol fed rabbits in vivo. The height of the dicrotic notch was used as an index of general arterial vasodilatation.

METHODS

Twenty eight rabbits were divided into three study groups; a control group (group 1, n = 8), a group fed 1% cholesterol (group 2, n = 10), and a group fed 1% cholesterol with the addition of 0.2% vitamin E after four weeks (group 3, n = 10). After six weeks on diet the vasodilator responses to acetylcholine and glyceryl trinitrate were measured by photoplethysmography of the rabbit ear. Recordings were made during light sedation at baseline and during infusion of acetylcholine (1.5, 3.0, 6.0, and 12 micrograms.min-1) and glyceryl trinitrate (3.75, 7.5, and 15.0 micrograms.min-1). In a second set of experiments with control fed rabbits (n = 5), acetylcholine infusions were given before and after infusion of L-nitro-arginine (15 mg).

RESULTS

The relative height of the dicrotic notch (which predominantly indicates arterial tone in the larger vessels) was reduced by acetylcholine in a dose dependent manner, but in cholesterol fed rabbits (group 2) this response was significantly decreased. Rabbits receiving concomitant dietary vitamin E responded in a similar manner to controls. The difference was most prominent using acetylcholine at a dose of 3.0 micrograms.min-1, where the mean change from baseline was 11(SEM 4)% in group 2, compared to 31(6)% in group 1 (p = 0.01), and to 26(5)% in group 3 (p = 0.02). Similar differences between the groups were observed for the increase in heart rate during acetylcholine infusions. In contrast, the responses to glyceryl trinitrate were similar in all groups. After infusions of L-nitro-arginine, the responses to acetylcholine were blunted.

CONCLUSIONS

Supplementation with vitamin E restored the otherwise reduced vascular response to acetylcholine in cholesterol fed rabbits. Analysis of photoplethysmographic pulse curves is a simple non-invasive method of evaluating arterial vasodilator effects. However, the nature of the measured dilator response needs to be characterised further.

Granulocyte-macrophage colony-stimulating factor stimulates macrophages to respond to IgE via the low affinity IgE receptor (CD23)

We have found increased concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the bronchoalveolar lavage fluid of 11 patients with nocturnal asthma (15.3 +/- 4.6 pg/ml) compared with normal subjects (2.3 +/- 6.1 pg/ml) (p = 0.03). In contrast to patients with asthma, low affinity IgE receptors (Fc epsilon RII or CD23) are not expressed on monocytes obtained from healthy, nonatopic donors. Fc epsilon RII expression was induced by the cytokines GM-CSF and interleukin (IL)-4 either alone or in combination. As assessed by flow cytometry, the combination of IL-4 and GM-CSF was found to be synergistic, inducing up to 54.8% +/- 4.6% Fc epsilon RII-positive monocytes compared with a maximum of 27.4% +/- 5.0% and 30.0% +/- 4.0% with IL-4 and GM-CSF alone, respectively (p < 0.05 compared with either cytokine alone). Human monocytes from the peripheral blood of seven normal subjects were cultured for 24 hours with and without IL-4 or GM-CSF. With IL-4, addition of IgE/anti-IgE complexes failed to induce IL-1 secretion and inhibited IL-1 secretion induced by lipopolysaccharides. The addition of GM-CSF or IgE immune complexes alone resulted in no additional IL-1 secretion in supernatants of the untreated monocytes, whereas the IgE complexes did stimulate IL-1 secretion by monocytes cultured in GM-CSF, as measured by ELISA (from 0.7 +/- 0.2 ng/ml to 2.3 +/- 0.5 ng/ml; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Oral desensitization to rifampin and ethambutol in mycobacterial disease

The incidence of disease caused by Mycobacterium tuberculosis (including drug-resistant strains) and M. avium complex (MAC) is increasing. Hypersensitivity reactions to antimycobacterial agents are relatively uncommon, but when they occur they may result in cessation of therapeutic medications. We report our experience with rapid oral desensitization to ethambutol and rifampin in a group of 10 patients with mycobacterial disease who had experienced cutaneous hypersensitivity reactions to these drugs. An adaptation of the rapid oral desensitization protocol for penicillin was used, with the dosing intervals increased to account for the different kinetics of these drugs. Adverse reactions were few and easily treated without necessitating cessation of therapy. We conclude that oral desensitization to rifampin and ethambutol by our protocol is safe and effective, allowing these patients to proceed with an optimal antimycobacterial regimen.

Diffuse pulmonary infiltrates in hypogammaglobulinemia

This is the first case report of lymphangitic carcinomatosis from adenocarcinoma of the stomach presenting as interstitial lung disease in a patient with CVH. Adenocarcinoma of the stomach occurs with increased frequency and at an earlier age in CVH as compared with the normal population. This diagnosis should be kept in mind during evaluation of patients with CVH. Periodic examinations of stool for occult blood should be performed. Aggressive diagnostic evaluation should be undertaken in any CVH patient with gastric complaints, as well as careful follow-up in patients with pernicious anemia, atrophic gastritis, or achlorhydria with regard to cancer screening.

Atypical eating disorder masquerading as recurrent acute pancreatitis: the value of multiple pancreatic serological markers

A 28-year-old woman with nausea, vomiting, and abdominal pain had been hospitalized elsewhere on 13 separate occasions over the year before this admission for similar episodes thought to be secondary to acute pancreatitis. She had undergone repeated work-ups including endoscopic retrograde cholangiopancreatography, computed tomographic scan, and exploratory laparotomy. There was a discrepancy between her unremarkable physical examination and extremely elevated amylase (3,210 U/L) which suggested nonpancreatic hyperamylasemia; normal serum pancreatic isoamylase, trypsinogen, and lipase confirmed this suspicion. The patient was noted to have self-induced vomiting in the hospital which she admitted was frequent behavior. her psychiatric disturbance was characterized as an atypical eating disorder. This case illustrates that hyperamylasemia in association with abdominal pain, nausea, and vomiting may not be secondary to pancreatitis and that use of a second serum marker (such as trypsinogen, lipase, or isoamylase) helps to establish a definitive diagnosis.

CO2 breathing of children

In 20 co-operative paediatric patients without cardiopulmonary disease, 2 and 4% CO2 in air were given to breathe and the ventilatory response as well as end-tidal CO2 were recorded. A rise of ventilation concomitant with a rise in alveolar CO2 was seen in most cases. The amount of ventilatory response was less than that previously reported with tube rebreathing for any given rise in alveolar PCO2. It appears therefore, that in addition to the absolute level of PaCO2, the mode of presentation of the CO2 signal to chemosensitive areas also serves as an important determinant for the amount of the ventilatory response.