E-cigarette or vaping product use-associated lung injury

E-cigarette or vaping product use-associated lung injury is a recently recognised, acute pulmonary syndrome which has been reported (particularly from June to October 2019) throughout the USA, but not in Europe (although one probable case, in the UK, has been reported; Medicines and Healthcare products Regulatory Agency, 2020). It presents acutely, most often in young men, as severe pulmonary consolidation, usually with respiratory failure. The mortality is around 2%. The cause(s) are unknown, but it is associated with vaping, particularly using unlicensed cannabis-containing products with tetrahydrocannabinol. Vitamin E acetate, often present in tetrahydrocannabinol-containing vape products as a solvent, has been implicated, as it has been identified in the bronchoalveolar lavage fluid of patients with e-cigarette or vaping product use-associated lung injury. This article reviews the recent literature, including clinical features, presentation and investigations, and possible mechanisms, in the context of vaping practices in the USA and the UK.

Marijuana and the lung: hysteria or cause for concern?

Increasing cannabis use and legalisation highlights the paucity of data we have on the safety of cannabis smoking for respiratory health. Unfortunately, concurrent use of tobacco among marijuana smokers makes it difficult to untangle individual effect of marijuana smoking. Chronic cannabis only smoking has been shown in large cohort studies to reduce forced expiratory volume in 1 s/forced vital capacity via increasing forced vital capacity in chronic use contrary to the picture seen in tobacco smoking. The cause of this is unclear and there are various proposed mechanisms including respiratory muscle training secondary to method of inhalation and acute anti-inflammatory effect and bronchodilation of cannabis on the airways. While cannabis smoke has been shown to increase symptoms of chronic bronchitis, it has not been definitively shown to be associated with shortness of breath or irreversible airway changes. The evidence surrounding the development of lung cancer is less clear; however, preliminary evidence does not suggest association. Bullous lung disease associated with marijuana use has long been observed in clinical practice but published evidence is limited to a total of 57 published cases and only one cross-sectional study looking at radiological changes among chronic users which did not report any increase in macroscopic emphysema. More studies are required to elucidate these missing points to further guide risk stratification, clinical diagnosis and management.

Key points

Cannabis smoking has increased and is likely to increase further with relaxation of legalisation and medicinal use of cannabinoids.Chronic marijuana smoking often produces symptoms similar to those of chronic tobacco smoking such as cough, sputum production, shortness of breath and wheeze.Cessation of marijuana smoking is associated with a reduction in respiratory symptoms and no increased risk of chronic bronchitis.Spirometry changes seen in chronic marijuana smokers appear to differ from those in chronic tobacco smokers. In chronic marijuana smokers there is an increase in FVC as opposed to a definite decrease in FEV₁.Multiple case series have demonstrated peripheral bullae in marijuana smokers, but no observational studies have elucidated the risk.There is currently no clear association between cannabis smoking and lung cancer, although the research is currently limited.

Educational aims

To update readers on legalisation of recreational and medicinal cannabis.To summarise the evidence base surrounding the respiratory effects of inhaled marijuana use.To provide clinicians with an understanding of the main differences between cannabis and tobacco to be able to apply this to patient education.To highlight common respiratory problems among cannabis users and the need for recreational drug history taking.

Intrahepatic Kinetics of lndium-111-Labelled Platelets

The intrahepatic kinetics of 111indium-labelled platelets have been studied using dynamic gamma camera scintigraphy immediately following injection. Platelets labelled in saline with mIn-oxine or 111In-acetylacetonate underwent rapidly reversible hepatic sequestration, indicating that they were “activated”. Platelets labelled in plasma with 111In-tropolonate, however, did not display this phenomenon. On the assumption that plasma-labelled platelets display a normal initial bio-distribution, mean intrahepatic platelet transit time, as a factor of the transit time of 99m-Tc labelled red cells, was 1.45 ± SE 0.12 (n = 6), implying the normal presence of a small intrahepatic platelet pool. Unlike the liver, transit through the spleen was not sensitive to the labelling medium; thus the mean intrasplenic transit time of plasma-labelled platelets was 9.3 ± SE 0.7 min (n = 10), and of saline-labelled platelets 9.5 ± SE 0.3 min (n = 8).

Difenacoum Poisoning as a cause of Haematuria

A man presented with frank haematuria and a grossly prolonged prothrombin time. He was later found to have taken an overdose of difenacoum — a 'superwarfarin' rodenticide. The diagnosis was confirmed by a serum concentration of difenacoum of 0.6 μg ml-1. Overdosage with superwarfarins is discussed and the need for prolonged treatment with vitamin K1 highlighted.

Prolonged B cell depletion with rituximab is effective in treating refractory pulmonary granulomatous inflammation in granulomatosis with polyangiitis (GPA)

Pulmonary nodule formation is a frequent feature of granulomatosis with polyangiitis (GPA). Traditional induction therapy includes methotrexate or cyclophosphamide, however, pulmonary nodules generally respond slower than vasculitic components of disease. Efficacy of rituximab (RTX) solely for the treatment of pulmonary nodules has not been assessed. In this observational cohort study, we report patient outcomes with RTX in GPA patients with pulmonary nodules who failed to achieve remission following conventional immunosuppression. Patients (n = 5) with persistent pulmonary nodules were identified from our clinic database and retrospectively evaluated. Systemic manifestations, inflammatory markers, disease activity, concurrent immunosuppression, and absolute B cell numbers were recorded pre-RTX and at 6 monthly intervals following treatment. Chest radiographs at each time point were scored by an experienced radiologist, blinded to clinical details. Five patients with GPA and PR3-ANCA were evaluated (2 male, 3 female), mean age 34 (22-52) years. Pulmonary nodules (median 4, range 2-6), with or without cavitation were present in all patients. RTX induced initial B cell depletion (<5 cells/μL) in all patients but re-population was observed in 3 patients. Repeated RTX treatment in these 3 and persistent B cell depletion in the whole cohort was associated with further significant radiological improvement. Radiographic scoring at each time interval showed reduction in both number of nodules (P =  <0.0001) and largest nodule diameter (P =  <0.0001) in all patients for at least 18 months following B cell depletion. In summary, RTX therapy induces resolution of pulmonary granulomatous inflammation in GPA following prolonged B cell depletion.

Microbial contamination of domiciliary nebulisers and clinical implications in chronic obstructive pulmonary disease

Background and purpose

Domiciliary nebulisers are widely used in chronic obstructive pulmonary disease (COPD) but nebuliser cleaning practice has not been assessed in patients with COPD who are often elderly and may have severe disease and multiple comorbidities. We aimed to evaluate microbial contamination of home nebulisers used by patients with COPD.

Methods

Random microbiological assessment of domiciliary nebulisers was undertaken together with an enquiry into cleaning practices. We also examined the effectiveness of the trust-wide cleaning instructions in eradicating isolated microorganisms in a laboratory setting.

Results

The mean age of patients in this study was 71 (range 40–93) years, and in 68% of patients a large number of significant comorbidities were present. Forty-four nebuliser sets were obtained and 73% were contaminated with microorganisms at >100 colony forming units/plate. Potentially pathogenic bacteria colonised 13 of the 44 nebulisers (30%) and organisms isolated included Pseudomonas aeroginosa, Staphylococcus aureus, multidrug resistant Serratia marcesans, Escherichia coli and multiresistant Klebsiella spp, Enterobacteriaceae and fungus Fusarium oxysporum. Washing of nebuliser masks, chambers and mouthpieces achieved complete eradication of Gram-positive bacterial and fungal flora. Gram-negative organisms were incompletely eradicated, which may be attributed to the presence of biofilms. We also found that in patients with pathogenic organisms cultured on the nebuliser sets, there was a higher probability of occurrence of a COPD exacerbation with a mean number of exacerbations of 3.3 (SD=1) per year in the group in whom pathogens were isolated compared with 1.7 (SD=1.2) exacerbations per year in those whose sets grew non-pathogenic flora (p=0.02).

Conclusions

Nebulisers contaminated with microorganisms are potential reservoirs delivering serious pathogens to the lung. Relationships between nebuliser contamination, clinical infection and exacerbations require further examination, but is a potential concern in elderly patients with COPD with comorbidities who fail to effectively maintain reasonable standards of nebuliser cleanliness.

Effect of adding postoperative noninvasive ventilation to usual care to prevent pulmonary complications in patients undergoing coronary artery bypass grafting: a randomized controlled trial

OBJECTIVE

We compared the efficacy of noninvasive ventilation with bilevel positive airway pressure added to usual care versus usual care alone in patients undergoing coronary artery bypass grafting.

METHODS

We performed a 2-group, parallel, randomized controlled trial. The primary outcome was time until fit for discharge. Secondary outcomes were partial pressure of carbon dioxide, forced expiratory volume in 1 second, atelectasis, adverse events, duration of intensive care stay, and actual postoperative stay.

RESULTS

A total of 129 patients were randomly allocated to bilevel positive airway pressure (66) or usual care (63). Three patients allocated to bilevel positive airway pressure withdrew. The median duration of bilevel positive airway pressure was 16 hours (interquartile range, 11-19). The median duration of hospital stay until fit for discharge was 5 days for the bilevel positive airway pressure group (interquartile range, 4-6) and 6 days for the usual care group (interquartile range, 5-7; hazard ratio, 1.68; 95% confidence interval, 1.08-2.31; P = .019). There was no significant difference in duration of intensive care, actual postoperative stay, and mean percentage of predicted forced expiratory volume in 1 second on day 3. Mean partial pressure of carbon dioxide was significantly reduced 1 hour after bilevel positive airway pressure application, but there was no overall difference between the groups up to 24 hours. Basal atelectasis occurred in 15 patients (24%) in the usual care group and 2 patients (3%) in the bilevel positive airway pressure group. Overall, 30% of patients in the bilevel positive airway pressure group experienced an adverse event compared with 59% in the usual care group.

CONCLUSIONS

Among patients undergoing elective coronary artery bypass grafting, the use of bilevel positive airway pressure at extubation reduced the recovery time. Supported by trained staff, more than 75% of all patients allocated to bilevel positive airway pressure tolerated it for more than 10 hours.

Pulmonary-renal syndrome: a life threatening but treatable condition

Pulmonary renal syndrome (PRS) describes the occurrence of renal failure in association with respiratory failure, characterised by autoimmune-mediated rapidly progressive glomerulonephritis (RPGN) and diffuse alveolar haemorrhage (DAH), respectively. PRS is associated with significant morbidity and mortality, and prompt diagnosis and treatment significantly improve outcomes. Prompt diagnosis of PRS requires a high index of suspicion, as clinical features are non-specific, and immunological testing aids the diagnosis in many cases. The diagnostic evaluation of DAH and RPGN is outlined in the context of the important differential diagnoses. The commonest causes of PRS include antineutrophil cytoplasm antibody (ANCA)-associated vasculitis and antiglomerular basement membrane disease. As such, more emphasis has been placed on these two conditions in addition to an overview of the less common causes of PRS. We provide a practical review of the diagnostic evaluation, current treatment strategies and clinical outcomes of PRS for renal, respiratory and general physicians.

Relation between trunk fat volume and reduction of total lung capacity in obese men

Reduction in total lung capacity (TLC) in obese men is associated with restricted expansion of the thoracic cavity at full inflation. We hypothesized that thoracic expansion was reduced by the load imposed by increased total trunk fat volume or its distribution. Using MRI, we measured internal and subcutaneous trunk fat and total abdominal and thoracic volumes at full inflation in 14 obese men [mean age: 52.4 yr, body mass index (BMI): 38.8 (range: 36-44) kg/m(2)] and 7 control men [mean age: 50.1 yr, BMI: 25.0 (range: 22-27.5) kg/m(2)]. TLC was measured by multibreath helium dilution and was restricted (<80% of the predicted value) in six obese men (the OR subgroup). All measurements were made with subjects in the supine position. Mean total trunk fat volume was 16.65 (range: 12.6-21.8) liters in obese men and 6.98 (range: 3.0-10.8) liters in control men. Anthropometry and mean total trunk fat volumes were similar in OR men and obese men without restriction (the ON subgroup). Mean total intraabdominal volume was 9.41 liters in OR men and 11.15 liters in ON men. In obese men, reduced thoracic expansion at full inflation and restriction of TLC were not inversely related to a large volume of 1) intra-abdominal or total abdominal fat, 2) subcutaneous fat volume around the thorax, or 3) total trunk fat volume. In addition, trunk fat volumes in obese men were not inversely related to gas volume or estimated intrathoracic volume at supine functional residual capacity. In conclusion, this study failed to support the hypotheses that restriction of TLC or impaired expansion of the thorax at full inflation in middle-aged obese men was simply a consequence of a large abdominal volume or total trunk fat volume or its distribution.

Interstitial lung disease and ANCA-associated vasculitis: a retrospective observational cohort study

OBJECTIVES

ANCA-associated vasculitis and interstitial lung disease (ILD) are uncommon conditions. The occurrence of both diseases in the same patient is increasingly recognized. Our aim was to ascertain the characteristics and outcomes of patients with ILD and ANCA-associated vasculitis.

METHODS

A retrospective observational cohort study was performed. Patients who presented to the Hammersmith Hospital, London, with ANCA-associated vasculitis [granulomatosis with polyangiitis (Wegener's), microscopic polyangiitis (MPA) or Churg-Strauss syndrome] who also had ILD were included. Following hospital discharge, all patients were followed up in a multi-disciplinary vasculitis clinic. We recorded patient demographics, diagnostic tests, treatment, complications and mortality.

RESULTS

ILD was observed in 2.7% (n = 14) of our patients with ANCA-associated vasculitis (n = 510); all had MPO-ANCA and a clinical diagnosis of MPA, giving a prevalence of 7.2% in patients with MPA (n = 194). There was no significant difference in survival between patients with MPA and ILD and those with MPA alone.

CONCLUSION

It is important that physicians are aware of this clinical association and the presence of ILD should be considered in all patients with ANCA-associated vasculitis, especially those with MPO-ANCA. The possibility that patients with ILD may subsequently develop features of systemic vasculitis should also be remembered.

Similar efficacy of ciclesonide versus prednisolone to treat asthma worsening after steroid tapering

RATIONALE

Oral corticosteroids effectively treat asthma exacerbations but are associated with well-described side effects.

OBJECTIVE

This study compared the efficacy and safety of a high dose of an inhaled corticosteroid with oral prednisolone in patients with worsening of their asthma after medication withdrawal.

METHODS

Patients tapered off their inhaled corticosteroids until they reached predefined criteria of "worsening asthma". Randomized patients (n=130) were treated double blind with either ciclesonide 800mug twice daily (starting with 800mug hourly for 3h after randomization) or prednisolone 40mg once daily for 2 weeks. Spirometry, daily asthma symptoms, morning and evening peak expiratory flow and blood parameters were assessed in all, methacholine challenge and inflammatory measures were determined in induced sputum in a subset of patients.

RESULTS

Ciclesonide was as effective as prednisolone in improving forced expiratory flow in 1s, morning peak expiratory flow and symptoms, the latter improving more rapidly with ciclesonide. No differences were found in methacholine responsiveness or inflammatory measures in sputum or blood. Ciclesonide caused significantly less reduction in morning plasma cortisol levels (p<0.0001).

CONCLUSION

This study shows that inhaled ciclesonide (800mug twice daily) has comparable efficacy to oral prednisolone (40mg once daily) to regain asthma control in patients with asthma worsening. The more rapid onset and smaller effect on cortisol suppression suggest a better safety profile of ciclesonide.

A 9-yr evaluation of carrier erythrocyte encapsulated adenosine deaminase (ADA) therapy in a patient with adult-type ADA deficiency

Adenosine deaminase (ADA) deficiency is an inherited disorder which leads to elevated cellular levels of deoxyadenosine triphosphate (dATP) and systemic accumulation of its precursor, 2-deoxyadenosine. These metabolites impair lymphocyte function, and inactivate S-adenosylhomocysteine hydrolase (SAHH) respectively, leading to severe immunodeficiency. Enzyme replacement therapy with polyethylene glycol-conjugated ADA is available, but its efficacy is reduced by anti-ADA neutralising antibody formation. We report here carrier erythrocyte encapsulated native ADA therapy in an adult-type ADA deficient patient. Encapsulated enzyme is protected from antigenic responses and therapeutic activities are sustained. ADA-loaded autologous carrier erythrocytes were prepared using a hypo-osmotic dialysis procedure. Over a 9-yr period 225 treatment cycles were administered at 2-3 weekly intervals. Therapeutic efficacy was determined by monitoring immunological and metabolic parameters. After 9 yr of therapy, erythrocyte dATP concentration ranged between 24 and 44 micromol/L (diagnosis, 234) and SAHH activity between 1.69 and 2.29 nmol/h/mg haemoglobin (diagnosis, 0.34). Erythrocyte ADA activities were above the reference range of 40-100 nmol/h/mg haemoglobin (0 at diagnosis). Initial increases in absolute lymphocyte counts were not sustained; however, despite subnormal circulating CD20(+) cell numbers, serum immunoglobulin levels were normal. The patient tolerated the treatment well. The frequency of respiratory problems was reduced and the decline in the forced expiratory volume in 1 s and vital capacity reduced compared with the 4 yr preceding carrier erythrocyte therapy. Carrier erythrocyte-ADA therapy in an adult patient with ADA deficiency was shown to be metabolically and clinically effective.

Results of endoscopic surgery and intralesional steroid therapy for airway compromise due to tracheobronchial Wegener's granulomatosis

BACKGROUND

Upper airway compromise due to tracheobronchial stenosis commonly occurs in patients with Wegener's granulomatosis (WG). There is at present no consensus on the optimal management of this life threatening condition.

OBJECTIVE

To assess the results of laryngo-tracheo-bronchoscopy, intralesional steroid therapy, laser surgery and dilatation in managing obstructive tracheobronchial WG.

METHODS

Records of 18 previously untreated stridulous patients with obstructive tracheobronchial WG, treated between 2004 and 2006, were prospectively recorded on an airway database and retrospectively reviewed. Information about patient and lesion characteristics and treatment details were recorded. Treatment progress was illustrated using a timeline plot, and intervention-free intervals were calculated with actuarial analysis.

RESULTS

There were nine males and the average age at presentation was 40 (16) years (range 13-74). There were 13 patients with tracheal and five with tracheal and bronchial lesions. The average tracheal lesion height was 8 (3) mm, located 23 (9) mm below the glottis. There were 1, 10 and 7 Myer-Cotton grade I, II and III lesions, respectively. Mean intervention-free interval following minimally invasive treatment was 26 (2.8) months. Following endobronchial therapy, the median intervention-free interval was 22 months (p>0.8 vs tracheal lesions). No patient required a tracheostomy or endoluminal stenting.

CONCLUSIONS

Intralesional steroid therapy and conservative endoluminal surgery is an effective strategy for treating airway compromise due to active tracheal and bronchial WG, obviating the need for airway bypass or stenting. We recommend the combination of endotracheal dilatation, conservative laser surgery and steroid therapy as the standard of care for treating airway compromise due to obstructive tracheobronchial WG.

Inhaled therapy in elderly COPD patients; time for re-evaluation?

OBJECTIVE

chronic obstructive pulmonary disease (COPD) prevalence steadily increases with age. However, the effectiveness of inhaled therapy in the elderly COPD population has rarely been formally evaluated. We studied a group of elderly patients with COPD with a range of severity, selected from one General Practice register to measure peak inspiratory flow (PIF) and assess patient perceived benefit.

METHODS

we recruited 53 randomly selected elderly patients with COPD (36 males) with a mean age of 73.5 years (range 65-89 years). The evaluation consisted of (i) information obtained from directed questions and (ii) objective measurements of the ability to generate adequate PIF for a variety of inhalers. Patients answered questions regarding ease of use, perceived benefit from and specific problems encountered with their inhaler. Three recordings of PIF were measured at varying inhaled resistances using the 'In-Check Dial'.

RESULTS

thirty-five were classified as mild, 17 moderate and 1 severe COPD. All patients used a metered dose inhaler (pMDI), and 12 of the patients also used a dry powder inhaler (DPI). Forty six per cent of patients using a pMDI and 17% of those using a DPI rated their device difficult to use. No patient used a nebuliser. Thirty-one of the 53 patients using just a pMDI felt they were able to perceive benefit in comparison to 4 of the 12 DPI users. Even though most DPI users (10/12) had rated their inhaler as easy to use, 50% were 'unsure' as to whether they received any clinical benefit. Most patients were unable to generate sufficient inspiratory flow to use the higher resistance DPI's and patients with COPD who were able to generate adequate PIF were invariably mild. A significant negative correlation was found between age and the PIF achieved when assessed using the high resistance device setting (R = 0.84, P<0.0001). Multivariate analysis showed the effect of age on PIF was independent of the disease grade.

CONCLUSIONS

elderly patients with COPD, even when in a stable clinical condition, may be unable to gain optimum benefit from their inhaler.

Inhaled allergen-driven CD1c up-regulation and enhanced antigen uptake by activated human respiratory-tract dendritic cells in atopic asthma

BACKGROUND

Dendritic cells (DC) mediate inflammation in rodent models of allergic airway disease, but the role played by human respiratory-tract DC (hRTDC) in atopic asthma remains poorly defined. Recent data suggest that CD1 antigen presentation by hRTDC may contribute to asthma pathogenesis.

OBJECTIVE

To investigate the influence of hRTDC on the balance between atopy and allergic asthma in human subjects and to determine whether CD1 expression by hRTDC is modulated during asthmatic inflammation.

METHODS

Sputum cells were induced from steroid-naïve, allergen-challenged and allergen-naïve subjects (atopic asthmatics, atopic non-asthmatics and non-atopic controls). hRTDC were identified using monoclonal antibody labelling and analysis by flow cytometry.

RESULTS

hRTDC stained HLA-DR(+) (negative for markers of other cell lineages) were predominantly myeloid and comprised approximately 0.5% of viable sputum cells. Sputum cells were potent stimulators of allogeneic CD4(+) naïve T cells and enrichment/depletion experiments correlated stimulatory potency with DC numbers. Sputum contained cells that exhibited typical dendritic morphology when analysed by electron microscopy. Myeloid hRTDC were endocytically active, but uptake of FITC-dextran was enhanced in cells from asthmatics (P<0.001). Despite their increased endocytic capacity, asthmatic myeloid hRTDC appeared mature and expressed increased levels of maturation markers (P<0.05-P<0.001), CD1c, CD1d and langerin (P<0.05). CD1c expression by asthmatic myeloid hRTDC was enhanced upon in vivo allergen challenge (three to ninefold within 24 h; P<0.05). CD11c(-)CD123(high) hRTDC were only detected in asthmatic sputum and were increased in number following allergen challenge.

CONCLUSION

Despite limited cell numbers, it proved possible to analyse human RTDC in induced sputum, providing evidence that increased antigen uptake and enhanced CD1 presentation by activated hRTDC may contribute to allergic airway disease. CD1 presentation by hRTDC in atopic asthma may therefore constitute a novel target for future intervention strategies.

Concurrent therapy (long acting beta agonists and inhaled corticosteroids) in the management of asthma

BACKGROUND

Asthma is a clinical syndrome characterised by chronic inflammation of the lower respiratory tract in which many cells and cellular elements play a role, in particular mast cells, eosinophils, T-lymphocytes, macrophages, neutrophils and epithelial cells. Patients often require long-term anti-inflammatory and reliever drugs to achieve a normal life. This review aims to highlight role of concurrent therapy in the optimal management of asthma.

METHOD

A review of relevant literature was conducted using available medical journals and Science direct via the Internet. The key words employed were: asthma, concurrent therapy, long acting beta agonists and corticosteroids. British Thoracic Society and The National Heart, Lung and Blood Institute websites were also used in sourcing information for this review.

RESULTS

Several studies support adding long acting beta agonists (LABA) to inhaled corticosteroids (ICS) than doubling the dose of ICS. This improves lung function, symptoms control and allows the dose of each drug to be adjusted to the patients'needs.

CONCLUSION

This review was able to show that concurrent use LABA and ICS in asthmatics helps in adjusting their treatment within limits hence achieving control of the condition with minimal side effects.

Methotrexate therapy of oral corticosteroid-dependent asthmatics reduces serum immunoglobulins: correlation with clinical response to therapy

BACKGROUND

Concomitant methotrexate (MTX) therapy of oral corticosteroid (CS)-dependent asthmatics has been shown to spare CS therapy, but the mechanism is unknown. In a previous report, we showed that MTX increases T cell inhibition by CS. In this report we focus on effects of MTX on immunoglobulin concentrations and their possible clinical relevance.

OBJECTIVE

To monitor changes in circulating leucocytes and Ig in a group of these patients during MTX therapy, and to relate these changes to clinical 'response' as defined by oral CS reduction.

METHODS

Sixteen severe asthmatics dependent on oral prednisolone 15 (7.5-25) mg/day in addition to high dose inhaled CS were treated with MTX 15 mg intramuscularly, weekly for 28 weeks. Prednisolone dosages were maintained constant for 12 weeks then reduced systematically over the next 16 weeks provided that asthma control did not deteriorate. Patients were classified a priori as 'responders' or 'non-responders' to MTX (reduction of initial oral prednisolone requirement by >or=50% or <50%, respectively). Patients were followed-up for a further 12 weeks after MTX withdrawal. Serum Ig and differential blood leucocyte counts were measured at baseline, 12, 28 and 40 weeks.

RESULTS

MTX therapy allowed significant, but individually variable, reductions in oral prednisolone dosages (P<0.00001) without alteration of lung function or symptoms. This was associated with significant reductions in mean serum concentrations of Ig of all classes, which reversed following MTX withdrawal. Reductions in IgE and IgG were significantly greater in the MTX 'responders' as compared with 'non-responders', and changes in IgE, IgG and IgM correlated with changes in prednisolone requirements. Differential blood leucocyte counts showed no significant variation.

CONCLUSION

MTX therapy reduced oral CS requirements in these severe asthmatics to a degree which correlated with reduced circulating Ig but not lymphopaenia, suggesting a possible cause and effect relationship. These reductions might also contribute to the documented incidence of opportunistic infection in these circumstances.

Peripheral Pulmonary Artery Pseudoaneurysms and Massive Hemoptysis

OBJECTIVE

The aim of this study was to determine the incidence and etiology of pulmonary artery pseudoaneurysms in patients undergoing bronchial angiography for massive hemoptysis and to assess patient outcome after the embolization of these pseudoaneurysms.

CONCLUSION

Peripheral pulmonary artery pseudoaneurysms occur in up to 11% of patients undergoing bronchial angiography for hemoptysis. These are often most easily appreciated on bronchial and/or nonbronchial systemic arterial angiograms because of complete reversal of flow in pulmonary artery branches in the diseased lung. Embolization of bronchial and nonbronchial systemic arteries alone may not be sufficient therapy to control hemoptysis, and occlusion of the pseudoaneurysm itself via a pulmonary artery approach is recommended.

Adjustable and fixed dosing with budesonide/ formoterol via a single inhaler in asthma patients: the ASSURE study

Patient-guided management of asthma using adjustable dosing of budesonide/formoterol in a single inhaler (Symbicort) was compared with fixed dosing in an open-label, multicentre, randomised study. Patients, uncontrolled on an inhaled corticosteroid (ICS) or controlled on an ICS and a long-acting beta2-agonist, entered a 4-week run-in period and received budesonide/formoterol (80/4.5 or 160/4.5 microg), 2 inhalations b.i.d. Following randomisation, the fixed-dosing group (n = 764) continued this regimen for a further 12 weeks. The adjustable-dosing group (n = 775) could step down to 1 inhalation b.i.d. if symptoms were controlled, and, at early signs of worsening symptoms, promptly step up to 4 inhalations b.i.d. for < or = 2 weeks. During run-in, National Heart, Lung and Blood Institute symptom-severity grading was maintained in 60% and improved in 31% of patients, clinic peak flow increased from 400 to 4191/min (P<0.001), and health-related quality of life (overall MiniAQLQ) improved from 4.6 to 5.4 (P<0.001). Patients effectively used the adjustable-dosing regimen; 79% reduced budesonide/formoterol dosage and, compared with fixed dosing, the number of inhalations were significantly lowered (3.2 vs. 3.8 inhalations/day, P<0.05). Both regimens were well tolerated. In both groups, symptom control was maintained or improved in 85-86% of patients, and 94% experienced no treatment failures. Consistent with current guidelines, adjustable maintenance dosing with budesonide/formoterol in a single inhaler provides effective asthma control at reduced medication doses.

The effect of the steroid-sparing response to low-dose methotrexate on bone metabolism in glucocorticoid-dependent asthmatics

BACKGROUND

The skeletal effects of low-dose methotrexate (MTX), in glucocorticoid-dependent asthmatics (GCDA), are unknown.

METHODS

We studied 9 patients from a total of 26 chronic GCDA who completed 28 weeks of MTX (15 mg weekly, intramuscularly). Prednisolone dose was not altered during the first 12 weeks, and was then reduced between 12 and 28 weeks. Mean (S.E.M.) age of the patients was 54 (4.0) years. They had normal bone mineral density (BMD), were not taking medication that affected bone metabolism (except prednisolone and inhaled corticosteroids) and all achieved at least 50% reduction in prednisolone dose at 28 weeks. Blood and urine samples were obtained at baseline, 12, 28 and 40 weeks for measurement of serum osteocalcin (OC) and bone alkaline phosphatase (Bone-ALP) as formation markers and urinary deoxypyridinoline (DPD) and N-terminal cross-linked telopeptide of type I collagen (NTX-I) as resorption markers.

RESULTS

Concurrently with the changes in prednisolone dosage serum OC levels increased significantly at 28 weeks (p<0.008) (8.1+/-1.0 ng/ml) compared to baseline (4.7+/-0.6 ng/ml) and 12 weeks (5.1+/-0.6 ng/ml), but trended back by 40 weeks (6.6+/-0.6 ng/ml). No significant changes were observed for the other bone markers between baseline and the other time points.

CONCLUSIONS

The beneficial effects of steroid reduction on bone metabolism do not appear to be impaired by concomitant MTX treatment at least over 12 weeks.

Methotrexate therapy in asthma increases T cell susceptibility to corticosteroid inhibition

BACKGROUND

Concomitant methotrexate (MTX) therapy of severe, oral corticosteroid-dependent asthmatics has been shown to be corticosteroid sparing, but the mechanism is unknown. We hypothesized that MTX therapy of these patients increases the susceptibility of their T cells to corticosteroid inhibition.

OBJECTIVE

To measure prednisolone inhibition of lectin-induced proliferation of peripheral blood T cells from a group of these patients before, during and following MTX therapy.

METHODS

Eighteen severe asthmatics (median (range) age 56 (33-68) years, FEV1 61 (38-69)% predicted, dependent on oral prednisolone 15 (7.5-25) mg/day in addition to high-dose, inhaled corticosteroids) were treated with MTX 15 mg intramuscularly, weekly for 28 weeks. After 12 weeks of MTX, oral prednisolone dosages were reduced systematically over 16 weeks, provided that asthma control did not deteriorate. Patients were followed for a further 12 weeks after MTX withdrawal. Concentration-dependent, prednisolone inhibition of lectin-induced proliferation of peripheral blood T cells was measured just prior to MTX therapy (week 1) and at weeks 12, 28 and 40, and IC50 concentrations were interpolated.

RESULTS

By week 28 of MTX therapy, patients were able to reduce oral prednisolone dosages from (median, SIQR) 15 (10-20.5) to 5.9 (1.4-9.4) mg/day (P<0.01) without alteration of lung function and symptoms, while median IC50 values for prednisolone inhibition of peripheral blood T cell proliferation were reduced from 49 (21-144) to 4 (1-9) nm (P<0.0001). These increased again to 15 (9.4-25.7) mg/day and 36 (18-67) nm, respectively, following MTX withdrawal. A correlation (P<0.01) was observed between percentage reductions in prednisolone dosages in vivo and fold changes in prednisolone IC50in vitro between weeks 12 and 28.

CONCLUSION

This effect of MTX may at least partly account for its oral corticosteroid-sparing effect in severe asthma.

Addition of salmeterol to fluticasone propionate treatment in moderate-to-severe asthma

This study was designed to determine whether the benefit of adding salmeterol was superior to doubling the dose of fluticasone propionate (FP) over 6 months, compared to a control group who remained on a lower dose of FP. The multi-centre, double-blind, parallel group study involved 496 symptomatic asthmatic patients with a history of exacerbations on 500-800 micrograms (microg) inhaled corticosteroids (ICS) twice daily (b.d.) in a broadly representative group of 100 hospitals and general practices in six countries. Two doses of FP--250 microg b.d. (FP250) or 500 microg b.d. (FP500)--were compared with the lower dose of FP plus a long-acting beta2-agonist, salmeterol 50 microg b.d. (SM/FP250). Patients symptomatic on the run-in dose of FP250 alone formed the control group in the treatment period. Over 6 months, SM/FP250 significantly improved mean morning peak expiratory flow rates (amPEF) by 42.1 l/min, more than twice the improvement achieved with either dose of FP alone. SM/FP250 also resulted in more symptom-free days and nights (P < 0.002) and days and nights with no relief medication (P < 0.001). The number of severe exacerbations was low: 3, 6 and 8% in the SM/FP250, low- and high-dose FP groups, respectively. This study confirms that adding salmeterol to low-dose inhaled FP offers greater improvements than either maintaining or doubling the dose of FP. Significant benefit was gained from adding salmeterol in a group of patients who appeared to have been at the top of their steroid dose-response curve receiving FP250. There was no evidence of tolerance and a low incidence of exacerbations in all treatment groups.

Early clinical investigation of Viozan (sibenadet HCl), a novel D2 dopamine receptor, beta2-adrenoceptor agonist for the treatment of chronic obstructive pulmonary disease symptoms

Viozan, (Sibenadet HCl, AR-C68397AA) is a dual D2 dopamine receptor, beta2-adrenoceptor agonist that combines bronchodilator activity with the sensory afferent modulating effects associated with D2-receptor agonism. Investigation in animal models of key chronic obstructive pulmonary disease (COPD) symptoms has demonstrated that sibenadet effectively inhibits sensory nerve activity, thereby reducing reflex cough, mucus production and tachypnoea. The results of the early clinical evaluation of this novel agent are reported. An initial proof of concept study (Study 1) aimed to determine the clinical potential of this novel agent by assessing the effects of three doses of sibenadet therapy relative to placebo, with two commonly used bronchodilators, intended to provide a benchmark against which sibenadet activity could be judged. In all, 701 patients were randomized to one of three sibenadet dose groups (400, 600 or 1000 microg ex valve), salbutamol 200 microg, ipratropium bromide (IB) 40 microg or placebo, all three times daily via pressurized metered dose inhaler (pMDI) for 4 weeks. Once the results of Study 1 had been evaluated, a dose-ranging, study (Study 2) involving 872 patients randomized to receive sibenadet (45, 270, or 495 microg ex actuator), or placebo all three times daily via pMDI, for 6 weeks commenced. Both studies were preceded by a 2-week baseline phase and followed by a 2-week follow up period.The primary efficacy variable identified changes in key COPD symptoms over the treatment period (compared with baseline data) as determined by the novel Breathlessness, Cough and Sputum Scale (BCSS). In addition, data on lung function, health-related quality of life and adverse events were collected. Patients receiving sibenadet therapy three times daily exhibited statistically significantly greater improvements in BCSS total score than those receiving placebo or bronchodilator therapy alone. A clear dose-response was evident in Study 2. Symptom improvement in this study was also accompanied by improved lung function and health-related quality of life. Sibenadet therapy was well tolerated with an adverse events profile comparable to current bronchodilator therapy. These data were viewed as extremely encouraging, warranting further, large-scale clinical investigation.

Safety of formoterol by Turbuhaler as reliever medication compared with terbutaline in moderate asthma

The present study compared the safety of 4.5 microg formoterol with 0.5 mg terbutaline, both by Turbuhaler and used as needed, in addition to regular formoterol in moderate asthma. In this double-blind parallel-group study, 357 patients taking a moderate-to-high dose of inhaled corticosteroids and additional terbutaline (2-5 inhalations x day(-1) during run-in) were randomised to either formoterol or terbutaline as needed in addition to formoterol 9 microg b.i.d. over 12 weeks. Adverse events, serum potassium levels, electrocardiogram, vital signs and lung function were assessed monthly; peak expiratory flow and severe asthma exacerbations were recorded daily. Patients used 2.16 (range 0.0-6.3) formoterol and 2.34 (range 0.1-7.5) terbutaline relief inhalations x day(-1). No clinically significant differences in safety variables were found between treatments. Statistically greater increases in cardiac frequency (2.6 beats x min(-1), p=0.03) were found on terbutaline. There were 44 and 52 severe asthma exacerbations with formoterol and terbutaline, respectively, with no significant difference in time to first exacerbation. There was also no difference between treatments for other efficacy measures (peak expiratory flow, forced expiratory volume in one second and morning/evening symptom scores). Formoterol 4.5 microg as needed was at least as safe, well tolerated and effective as terbutaline 0.5 mg in stable patients (requiring up to 6 relief inhalations x day(-1)) taking formoterol plus inhaled corticosteroids regularly over 12 weeks.

Circadian rhythm of cutaneous hypersensitivity reactions in nocturnal asthma

BACKGROUND

Diurnal variation in mast cell discharge may play a central role in the early morning fall in peak expiratory flow rate (PEFR) in nocturnal asthmatic patients.

METHODS

We tested the hypothesis that there is a circadian rhythm in mast cell response to allergen in 15 patients with nocturnal asthma by measuring the magnitude of cutaneous hypersensitivity reactions at 0600, 1200, 1800, and 2400 hours. Pre-admission, prick skin testing on the ventral aspect of the forearm to various allergens was performed. The allergen producing the largest wheal was tested at six sites on one forearm. Response was quantified after 20 minutes by measuring the area of the wheal produced using planimetry. Every six hours the skin testing was repeated at six new sites on alternating forearms. The average area of the six wheals was calculated and recorded at each time. The prick skin technique was used at all times.

RESULTS

Maximal reactions occurred in 10 of the 15 patients at noon (P = .031, Friedman's two way analysis of variance). In these 10 patients wheal area at the time of maximum reactivity was on average 3.3-fold higher than at the time of minimum reactivity. The mean wheal areas for all 15 patients at 0600, 1200, 1800, and 2400 hours were 34 mm2, 42 mm2, 34 mm2, and 35 mm2 respectively.

CONCLUSIONS

These observations support the concept of a circadian rhythm in mast cell activity in patients with severe nocturnal asthma.

Nebulized glyceryl trinitrate exerts acute bronchodilator effects in patients with acute bronchial asthma

Glyceryl trinitrate (GTN) is a potent smooth muscle relaxant and vasodilator. There are conflicting reports regarding its efficacy as a bronchodilator. The aim of this study was to examine whether nebulized GTN has bronchodilating effects in patients with acute bronchial asthma. We studied 18 patients (five female, 13 male) who were admitted to the hospital with acute severe asthma on two occasions, administering either 6 mg nebulized GTN or placebo (saline) in a double-blind, randomized, crossover fashion. Bronchial response was assessed by measurement of peak expiratory flow (PEF), forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). A systematic effect of this dose of GTN was demonstrated by a mean increase in heart rate of 38.1% (SEM=7.6%) after GTN administration from supine to erect posture, compared with 10.2% (SEM=1.8%) after placebo (P<0.005). Systolic blood pressure decreased by 8.7% (SEM=1.1%) after GTN, compared with 4.0% (SEM=2.1%) after placebo (P<0.05). Diastolic blood pressure did not change significantly. Baseline PEF, FEV1 and FVC did not differ on the two experimental days; however, acute bronchodilating effects were seen: PEF (l/min); 368 (21) pre-GTN, 411 (22) post-GTN and 384 (23) post-placebo (P<0.001). FEV1 (l); 2.12 (0.13) pre-GTN, 2.46 (0.15) post-GTN and 2.25 (0.16) post-placebo (P<0.001). FVC (l); 3.31 (0.17) pre-GTN, 3.75 (0.2) post-GTN and 3.54 (0.2) post-placebo (P<0.001). In conclusions, nebulized GTN has bronchodilating effects in patients with acute bronchial asthma. The exact mechanism of bronchodilation is not known, but it may be due to local effect on bronchial smooth muscles through nitric oxide or by systemic vasodilatation which leads to a decrease in pulmonary artery pressure and pulmonary vascular resistance, or an increase in systemic catecholamine release.

Comparison of two methods of processing induced sputum: selected versus entire sputum

Sputum analysis is increasingly used to assess airway inflammation in asthma. The analysis of sputum is currently performed with two techniques, i.e., analysis of selected sputum (plugs) and analysis of entire sputum. To investigate the diagnostic value of these two methods, we compared total and differential cell counts and supernatant eosinophil cationic protein (ECP) in selected and entire sputum collected on two occasions in a group of healthy and asthmatic subjects. We induced sputum with hypertonic saline in 18 asthmatics and in eight healthy subjects. On one occasion we analyzed selected sputum, and on another occasion we analyzed entire sputum. In each sample we measured total and differential cell counts and ECP concentration in supernatant. We found a higher percentage of eosinophils (15.3 versus 8.3%; p < 0.01), more viable nonsquamous cells (80.6 versus 71.8%; p < 0.01), and higher levels of ECP (548 versus 105 microg/L; p < 0.001) in selected sputum as compared with entire sputum, whereas the percentage of neutrophils was higher in the entire sputum (42.7 versus 33.3%; p < 0.05). The percentage of eosinophils and ECP concentration were significantly and similarly increased in both selected and entire sputum of asthmatic subjects, i.e., independent of the method of sputum analysis. In conclusion, the selected sputum method may indeed provide more viable cells, more eosinophils, and a higher concentration of ECP. However, both the selected sputum and the entire sputum method have the same diagnostic value in distinguishing asthmatics from healthy subjects.

Bronchoalveolar lavage causes decrease in PaO2, increase in (A-a) gradient value and bronchoconstriction in asthmatics

The aims of this study were to (1) record the changes of (arterial oxygen partial pressure) PaO2, (arterial carbon dioxide partial pressure) PaCO2, (percentage saturation of haemoglobin with oxygen in arterial blood) SaO2 and alveolar-arterial (A-a) oxygen gradiant resulting from bronchoalveolar lavage (BAL) in asthmatic and normal subjects; (2) measure changes in forced expiratory volume in 1 s (FEV1), vital capacity forced (FVC) associated with BAL; and (3) assess possible predictive factors for the degree of hypoxaemia and impairment of spirometry resulting from BAL. Bronchoscopy and BAL (150 ml) were performed in 24 asthmatics and 15 healthy subjects. Serial arterial blood samples (radial artery) were obtained in all subjects: T1 and before T2 after local anaesthesia; T3 at end of bronchoscopy; T4 after BAL and 5 min, 15 min, 1 h, 2 h, 8 h and 24 h (T5-T10) after the procedure, FEV1 and FVC were measured immediately before and 5 min afer bronchoscopy. Baseline PaO2 was lower in asthmatics (10.2 +/- 0.8 kPa) than in healthy subjects (10.8 +/- 0.8). Both groups showed a significant decrease in PaO2, and a significant widening in (A-a) oxygen tension gradiant at T3-9, with respect to T1 (P < 0.05). PaO2 reached a significantly lower value in asthmatics (7.1 +/- 0.6 kPa) than in HS (7.7 +/- 0.5; P < 0.05). In asthmatics, FEV1, FVC and the ratio FEV1/FVC decreased significantly after BAL (P < 0.001). In healthy subjects, FEV1 and FVC decreased significantly (P < 0.001), whereas FEV1/FVC did not. The fall in FEV1 after BAL was significantly greater in asthmatics (32.4 +/- 10.0%) than in healthy subjects (17.7 +/- 4.6; P < 0.001). Severity of asthma, basline FEV1 or initial PaO2 did not predict the degree of hypoxaemia or the fall of FEV1. It is concluded that BAL causes more severe hypoxaemia and a greater decrease in FEV1 in asthmatics compared to healthy subjects, strongly supporting the recommendation of special caution and careful monitoring when BAL is undertaken in asthmatics.

Dissociation between airway inflammation and airway hyperresponsiveness in allergic asthma

In asthma, the acute increment of airway responsiveness caused by exposure to allergen is associated with influx of eosinophils into the airways. The relationship between chronic airway hyperresponsiveness and airway inflammation is unclear, as they do not change consistently following long-term anti-inflammatory treatments. We studied 71 patients with chronic asthma and allergic sensitization to perennial allergens. Airway responsiveness was determined by inhalation of methacholine, and airway inflammation was quantified by induced sputum (n = 28) or bronchoalveolar lavage (n = 43) and bronchial biopsy (n = 20). The relationships between airway responsiveness and the numbers of different inflammatory cells were assessed by multiple regression analysis. No significant correlations were found between the degree of airway responsiveness and the numbers of inflammatory cells in sputum or bronchoalveolar lavage or bronchial biopsy. By contrast, baseline lung function was inversely related to the numbers of eosinophils and directly related to the numbers of macrophages. The eosinophil cationic protein contents of either sputum or bronchoalveolar lavage were significantly correlated with the percentages of eosinophils but not with airway responsiveness. We suggest that other factors (e.g., airway wall remodeling or autonomic dysfunction) may be responsible for most of the interindividual variability of airway responsiveness in asthma.

Effect of long-term beta2-agonist dosing on human cardiac beta-adrenoceptor expression in vivo: comparison with changes in lung and mononuclear leukocyte beta-receptors

BACKGROUND

Tachyphylaxis to the cardiac effects of beta-adrenoceptor stimulation after long-term beta2-agonist administration is well recognized, but the influence on global cardiac beta-adrenoceptor density has not been previously investigated in vivo. Positron emission tomography (PET) has made possible the noninvasive quantification of regional receptor density. This study assesses the effect of long-term beta2-agonist dosing on cardiac beta-adrenoceptors.

METHODS AND RESULTS

Beta-adrenoceptors in the hearts of 29 healthy male subjects aged 35 +/- 8 years were imaged and quantified in vivo by means of PET and compared with the receptor density in the same subjects' lung tissue. Mononuclear leukocyte (MNL) beta-receptor density was determined in vitro by means of a radioligand binding assay. Beta-receptor density was 8.41 +/- 2.03 pmol/gm tissue in heart, 10.81 +/- 1.91 pmol/gm tissue in lung, and 38.0 +/- 17.5 fmol/mg protein on MNLs. There was a weak relationship between cardiac and pulmonary beta-receptor densities (r = 0.45, p < 0.02) but not between cardiac and MNL receptor density. In seven subjects, the measurements were repeated after 2 weeks of albuterol treatment (4 mg orally twice daily and 200 microg inhaled four times daily in the first week, with doubling of the dose during the second week). After the albuterol treatment, beta-receptor density fell on average by 19% (p < 0.05) in the heart compared with 22% (p < 0.05) in the lung and 42% (p < 0.05) in MNLs. Correlations were found between the percentage changes in receptor density in heart and lung (r = 0.98, p < 0.001) and in heart and MNLs (r = 0.99, p < 0.002).

CONCLUSIONS

Two weeks of high-dose albuterol results in equivalent downregulation of beta-receptors in vivo, both in the lung and in the heart.

Dose equivalence and bronchoprotective effects of salmeterol and salbutamol in asthma

BACKGROUND

Salbutamol is the most widely prescribed short acting beta 2 agonist and salmeterol is the first long acting inhaled beta 2 agonist. The dose equivalence of salmeterol and salbutamol is disputed. Estimates of weight-for-weight dose ratio have ranged from 1:2 to 1:16. A study was undertaken to clarify the true dose ratio.

METHODS

The bronchoprotection afforded against repeated methacholine challenge by inhaled salmeterol 25 micrograms and 100 micrograms and salbutamol 100 micrograms and 400 micrograms was compared in a randomised, double blind, placebo controlled, crossover trial. Subjects were 16 stable asthmatics with a baseline forced expiratory volume in one second (FEV1) of > or = 65% predicted, screening concentration provoking a fall in FEV1 of 20% (PC20FEV1) of < or = 8mg/ml, and a shift in PC20FEV1 of more than two doubling concentration steps following inhalation of salbutamol 400 micrograms. On five separate occasions subjects underwent methacholine challenge before and 30 and 120 minutes after drug administration. PD20FEV1 was calculated for each challenge. FEV1 at 90 minutes after drug administration was also recorded.

RESULTS

Bronchoprotection afforded by salmeterol was increased at 120 minutes compared with 30 minutes and protection by salbutamol was decreased. Protection by both doses of salmeterol was similar to salbutamol 100 micrograms at 30 minutes but significantly greater at 120 minutes. FEV1 at 90 minutes was significantly greater after salmeterol 100 micrograms than after placebo, but there were no other significant differences between treatments. Maximal observed protection was equivalent for salmeterol 100 micrograms and salbutamol 400 micrograms.

CONCLUSIONS

The data are compatible with a weight-for-weight dose ratio for salmeterol:salbutamol of < or = 1:4.

Attenuation of propranolol-induced bronchoconstriction by frusemide

BACKGROUND

Inhaled propranolol causes bronchoconstriction in asthmatic subjects by an indirect mechanism which remains unclear. Inhaled frusemide has been shown to attenuate a number of indirectly acting bronchoconstrictor challenges. The aim of this study was to investigate whether frusemide could protect against propranolol-induced bronchoconstriction in patients with stable mild asthma.

METHODS

Twelve asthmatic subjects were studied on three separate days. At the first visit subjects inhaled increasing doubling concentrations of propranolol (0.25-32 mg/ml), breathing tidally from a jet nebuliser. The provocative concentration of propranolol causing a 20% reduction in FEV1 (PC20FEV1 propranolol) was determined from the log concentration-response curve for each subject. At the following visits nebulised frusemide (4 ml x 10 mg/ml) or placebo (isotonic saline) was administered in a randomised, double blind, crossover fashion. FEV1 was measured immediately before and five minutes after drug administration. Individual PC20FEV1 propranolol was then administered and FEV1 was recorded at five minute intervals for 15 minutes. Residual bronchoconstriction was reversed with nebulised salbutamol.

RESULTS

Frusemide had no acute bronchodilator effect but significantly reduced the maximum fall in FEV1 due to propranolol: mean fall 18.2% after placebo and 11.8% after frusemide. The median difference in maximum % fall in FEV1 within individuals between study days was 3.6% (95% CI 1.2 to 11.7).

CONCLUSIONS

Frusemide attenuates propranolol-induced bronchoconstriction, a property shared with sodium cromoglycate. Both drugs block other indirect challenges and the present study lends further support to the suggestion that frusemide and cromoglycate share a similar mechanism of action in the airways.

Induced sputum to assess airway inflammation: a study of reproducibility

BACKGROUND

Infiltration of the airways mucosa with activated inflammatory cells appears to be a major factor in the pathogenesis of asthma and other airway diseases. Examination of sputum provides a direct method to investigate airway inflammation non-invasively.

OBJECTIVES

The aim of the present study was to evaluate the reproducibility of cell counts on cytospins and fluid phase (eosinophil cationic protein, ECP) measurements in a selected portion of induced sputum. We aimed to confirm the validity of the tecnique by comparing measurements between stable asthmatics, allergic rhinithis and healthy subjects.

METHODS

Sputum was induced with hypertonic saline (4.5%) twice within one week in 53 stable asthmatics, 16 subjects with seasonal rhinitis (out of the pollen season), and 19 healthy subjects. Reproducibility was examined within sample (two different plugs of the same sample) between sample (two specimens of induced sputum obtained within one week) and between examiners on stable subjects taking into account sample size, number of examinations per patients and Confidence Interval (CI) of the estimates.

RESULTS

We have found that the method is highly reproducible within sample and between examiners for all types of cells and fluid phase measurements of ECP. It is reproducible between sample for eosinophils, macrophages, neutrophils and ECP, but not for lymphocytes and weakly for epithelial cells. Sputum from asthmatics, in comparison with the sputum of healthy subjects and subjects with rhinitis had higher eosinophils (asthmatics: 12.2% +/- 12.9, rhinitis: 0.4 +/- 0.8, normals: 0.4 +/- 0.7 (%) and ECP (asthmatics: 827 +/- 491 microg/L, rhinitis: 127 +/- 82 normals: 157 +/- 203). No significant differences were found between healthy subjects and subjects with rhinitis. Eosinophil counts were inversely correlated with FEV1 (r = -0.37) expressed as percentage of predicted, but not significantly correlated with PC20 methacholine (r = -0.28) or blood eosinophils (r = 0.26).

CONCLUSIONS

The importance of this study is the confirmation, within important statistical guidelines for a study of reproducibility, that the methods examined are reproducible and valid.

Pulmonary and cardiac beta-adrenoceptor density in vivo in asthmatic subjects

To examine whether there is a primary deficit in beta-adrenoceptor density in asthma, pulmonary and cardiac beta-receptor density was determined in vivo with positron emission tomography (PET) in 10 male asthmatic subjects (36 +/- 8 yr of age) and compared with that in 30 age-matched normal male subjects (36 +/- 8 yr of age). Pulmonary beta-receptor density was 10.3 +/- 1.8 pmol/g tissue for the asthmatic group and 10.9 +/- 1.9 for the normal group. Cardiac beta-receptor density was 9.1 +/- 3.3 pmol/g for the asthmatic group and 8.8 +/- 2.3 pmol/g for the normal group. There was no difference in either pulmonary or cardiac beta-receptor density between the two groups. In addition, an inverse relationship was observed between FEV1 % predicted and pulmonary beta-receptor density in asthmatic subjects. In conclusion, beta-receptor numbers are normal in untreated asthmatic subjects.

Anti-leukotriene intervention: is there adequate information for clinical use in asthma?

Various mediators of inflammation have been suggested as being important in the pathogenesis of asthma. These include histamine, acetylcholine, bradykinin, adenosine, prostaglandins D2 and F2 alpha, thromboxane A2, leukotrienes, PAF and, more recently, various cytokines. Intervention in the action of these mediators is proposed to offer therapeutic benefit, and recent advances in drug therapy have centred on two main approaches. Specific and potent leukotriene antagonists and inhibitors of leukotriene biosynthesis have emerged, and their effects against allergen challenge, cold-air- and exercise-induced bronchospasm and aspirin-sensitive asthma have been evaluated. A small number of studies have also been conducted in clinical asthma, with both acute and long-term (up to 20 weeks) efficacy studies being reported. A considerable degree of inter-individual variation is seen in the degree of protection afforded by leukotriene intervention. The extent to which inhibiting one set of inflammatory mediators can be expected to attenuate the asthmatic response can be questioned. As yet, there is no way of distinguishing leukotriene-related asthma from other types. It is likely, however, that leukotriene intervention may be useful in some patients with specific forms of the disease; for example, aspirin-sensitive asthma. Leukotriene intervention is unlikely to replace inhaled corticosteroids in the treatment of asthma, and its position in the guidelines for the management of asthma remain unclear thus far.

In vivo quantification of human pulmonary beta-adrenoceptors: effect of beta-agonist therapy

In human subjects, chronic beta2-agonist dosing reduces mononuclear leukocyte (MNL) beta-adrenoceptor numbers. The aim of this study was to investigate whether this downregulation also occurs in the lung. Seven healthy male subjects were treated for 2 wk with oral (up to 16 mg/d) and inhaled (up to 1.6 mg/d) albuterol (salbutamol in Europe). Pulmonary maximal beta-adrenoceptor binding capacity (Bmax) was determined in vivo using positron emission tomography (PET) and the beta-receptor antagonist ligand, 11C-labeled CGP-12177, before and after the 2-wk chronic dosing. MNL Bmax was also measured, using a radioligand binding assay and 3H-labeled CGP-12177. Bronchodilator responses to the beta2-agonist were determined after each PET scan by measuring the change in specific airway conductance (SGaw) after increasing doses of inhaled albuterol. Pulmonary and MNL Bmax fell by 22% +/- 14% (p < 0.05) and 42% +/- 19% (p < 0.05) respectively. The changes in pulmonary and MNL Bmax were correlated (r = 0.9, p < 0.05). There was also a reduction in the bronchodilator response to inhaled albuterol. In a further six subjects, pulmonary and MNL Bmax did not change during an acute infusion of albuterol (2 to 4 microg/kg/h). The reduction in pulmonary beta-adrenoceptor numbers after chronic albuterol dosing may be predictable from the changes observed in circulating MNL cells.

Determination of the minimum dose of lactose drug carrier that can be sensed during inhalation

Lactose is commonly used as a carrier for inhaled drugs. Twenty healthy volunteers without respiratory symptoms inhaled seven different doses of lactose and a placebo (empty) dose through the four place Diskhaler device, in order to determine the lowest dose that could be reliably sensed. The minimum dose for which all subjects reported taste or feel sensations was 10 mg. This has implications regarding the amount of carrier used in future drug delivery systems.