Trends in COPD mortality and hospitalizations in countries and regions of Asia-Pacific

Background and objective: The growing burden of COPD in the Asia‐Pacific region supports the need for more intensive research and analysis of the epidemiology of COPD to raise awareness of the disease and its causes, to ensure the development of effective national health policies and to facilitate equitable deployment of finite health‐care resources in the prevention and management of COPD. This study estimated and compared COPD mortality and hospital morbidity rates and trends in these rates over time across countries and regions of Asia‐Pacific. Methods: Data consistent with standard definitions of COPD (ICD‐9/ICD‐10) for the period 1991–2004 were obtained from national health statistics agencies. For countries/regions with complete national mortality and hospitalization data (Australia, Pacific Canada (British Columbia, Hong Kong, South Korea and Taiwan), annual age‐standardized mortality and hospitalization rates were calculated for men and women aged ≥ 40 years. Negative binomial regression modelling was used to estimate rate ratios for country/region, gender and age differences and general trends over time. Results: Mortality rates per 10 000 population ranged 6.4–9.2 in men, 2.1–3.5 in women and 3.7–5.3 overall in 2003. Corresponding ranges for morbidity were 32.6–334.7, 21.2–129 and 28.1–207.3 per 10 000. Trend analysis of data since 1997 produced annual percentage changes in mortality versus hospitalization of ?4.4% versus ?0.7% in Australia, ?3.6% versus 7.5% in Pacific Canada (British Columbia), ?7.15% versus ?5.6% in Hong Kong and ?2.9% versus ?4.2% in Taiwan. Conclusions: In Asia‐Pacific, overall mortality and morbidity rates are high and trends in mortality and morbidity vary between countries/regions. Differences in rates and trends for men and women most likely reflect the different trends in historical and prevalent smoking profiles for COPD in the different countries and regions.     

Obstructive Sleep Apnoea: From pathogenesis to treatment: Current controversies and future directions

Obstructive sleep apnoea (OSA) is a common disease, recognized as an independent risk factor for a range of clinical conditions, such as hypertension, stroke, depression and diabetes. Despite extensive research over the past two decades, the mechanistic links between OSA and other associated clinical conditions, including metabolic disorders and cardiovascular disease, remain unclear. Indeed, the pathogenesis of OSA itself remains incompletely understood. This review provides opinions from a number of leading experts on issues related to OSA and its pathogenesis, interaction with anaesthesia, metabolic consequences and comorbidities, cardiovascular disease, genetics, measurement and diagnosis, surgical treatment and pharmacotherapeutic targets.     

Pharmacogenetic characterization of indacaterol,a novel β2-adrenoceptor agonist

Background and purpose:

Indacaterol is a novel β₂-adrenoceptor agonist in development for the treatment of chronic obstructive pulmonary disease. The aim of this study was to investigate the comparative pharmacology of indacaterol in recombinant cells expressing the common polymorphic variants of the human β₂-adrenoceptor and in human primary airway smooth muscle (ASM) cells.

Experimental approach:

Chinese hamster ovarian-K1 cell lines expressing high and low levels of the common human β₂-adrenoceptor variants were generated [Gly16-Glu27-Val34-Thr164(GEVT), RQVT, GQVT] and also the rare GQVI variant. Human primary ASM cells were isolated from explants of trachealis muscle. Adenosine-3′,5′-cyclic-monophosphate production was used as an outcome measure.

Key results:

In both the low- and high-expression recombinant GEVT ‘wild type’ cell lines indacaterol is a high-efficacy agonist. Salmeterol and formoterol were identified as low- and high-efficacy agonists, respectively, and showed similar potencies to indacaterol irrespective of the β₂-adrenoceptor genotype. The I164 variant cell line was associated with a reduced capacity to generate adenosine-3′,5′-cyclic-monophosphate in response to β₂-adrenoceptor agonist. In the human primary ASM cells indacaterol gave a maximal response intermediate between that of salmeterol and formoterol.

Conclusions and implications:

These data demonstrate that indacaterol is a high-efficacy agonist in recombinant cell systems but acts with lower efficacy in human primary ASM cells. No marked genotype-dependent effects were observed for common variants; however, changes in I164 receptor activity were identified, which were dependent on the level of expression of β₂-adrenoceptors.     

Effects of Nitrogen Dioxide on Elastin and Collagen Contents of Lung

Male Syrian hamsters were exposed to 30 5 ppm nitrogen dioxide for 22 hr daily for 3 wk. Nitrogen dioxide-exposed hamsters sacrificed at various times during the 3 wk exposure showed a general loss of body weight and an increased dry lung weight when compared with the controls, which were housed in a similar, but nitrogen dioxide-free environment. Analysis of total lung collagen and total lung elastin revealed a net decrease in the moieties within 4 and 10 days, respectively, following commencement of nitrogen dioxide exposure. Total lung collagen returned toward pre-exposure levels by the 14th day of nitrogen dioxide exposure. Total lung elastin did not return toward normal until termination of nitrogen dioxide exposure. Recovery in room air for 3 wk following 21 days of nitrogen dioxide exposure restored the total pulmonary collagen and elastin to values similar to the control groups. These data suggest that the dynamics of elastin and collagen degradation and synthesis differ during and after nitrogen dioxide exposure. Lung collagen loss was observed earlier and was restored to normal values during the continuation of nitrogen dioxide exposure. Lung elastin loss occurred later and persisted during the entire period of exposure but returned to normal after exposure was terminated.     

Determinants of Pace-Terminable Ventricular Tachycardia: Implications for Implantable Antitachycardia Devices

The next generation of implantable antitachycardia devices incorporate anti-tachycardia pacing for the treatment of ventricular tachycardia. To evaluate the potential determinants of pace terminability, we analyzed 62 episodes of induced monomorphic ventricular tachycardia. We found that the tachycardia cycle length and cycle length variability are the major determinants of pace terminability. These findings should be considered in the designing of ventricular tachycardia detection and termination algorithms.     

Granulocyte colony-stimulating factor receptors in human acute myelocytic leukemia

The binding of granulocyte colony-stimulating factor (G-CSF) to normal and human acute myeloid leukemia (AML) cells was investigated with radiolabeled recombinant human G-CSF (rhG-CSF). In all 14 cases of primary AML specific receptors for G-CSF were demonstrated on purified blast cells. The average numbers of G-CSF receptors ranged from very low to 428 receptors per cell (mean). Normal granulocytes showed G-CSF binding sites on their surface at higher densities (703 to 1,296 sites per cell). G-CSF receptors appeared to be of a single affinity type with a dissociation constant (kd) ranging between 214 and 378 pmol/L for AML blasts and 405 to 648 pmol/L for granulocytes. In 12 of 14 cases, including those with relatively low specific binding, G-CSF was a potent inducer of DNA synthesis of blasts in vitro; therefore, apparently relatively few receptors are required to permit activation of AML cell growth. However, in two cases cell cycling was not activated in response to G-CSF despite G-CSF receptor availability. The results show that G-CSF receptors of high affinity are frequently expressed on the blasts of human AML, but their presence may not be a strict indicator of the proliferative responsiveness of the cells to G- CSF.     

Lung findings on high-resolution computed tomography in idiopathic ankylosing spondylitis--correlation with clinical findings, pulmonary function testing and plain radiography

Previous studies on the association of ankylosing spondylitis and abnormalities of the lung parenchyma have been based largely on plain radiography and pulmonary function testing. This study, although uncontrolled, is the first to use high-resolution computed tomography to examine the entire lung parenchyma in ankylosing spondylitis patients, and to correlate the findings with clinical assessment, plain radiography and pulmonary function testing. The study population comprised 26 patients meeting the New York criteria for idiopathic ankylosing spondylitis who attended the out-patient department at our institution. High-resolution computed tomography examination revealed abnormalities in 19 patients (70%): these included interstitial lung disease (n = 4), bronchiectasis (n = 6), emphysema (n = 4), apical fibrosis (n = 2), mycetoma (n = 1) and non-specific interstitial lung disease (n = 12). Plain radiography was abnormal in only four patients and failed to identify any patient with interstitial lung disease. All patients with interstitial lung disease on high-resolution computed tomography had respiratory symptoms and three of the four had evidence of a restrictive process on pulmonary function testing. This study raises, for the first time, the possible association between interstitial lung disease and ankylosing spondylitis, and highlights the use of high-resolution computed tomography in detecting such disease in ankylosing spondylitis patients.      

Mechanistic Heterogeneity of Junctional Ectopic Tachycardia in Adults

Spontaneous junctional ectopic tachycardia (JET) in adults is rare, and the electrophysiologic mechanism has not been definitively established. Two patients who presented with JET, not associated with cardiac surgery, were evaluated and studied in the electrophysiology laboratory, and electrophysiologic and pharmacologic maneuvers were performed to assess the mechanisms of tachycardia. The junctional tachycardia in Patient 1 manifested characteristics consistent with a triggered mechanism, and was sensitive to adenosine. The junctional tachycardia in Patient 2 manifested characteristics consistent with abnormal automaticity, and was insensitive to adenosine. This is a rare clinical example of abnormal automaticity. These two cases demonstrate that JET may be due to multiple mechanisms, with data consistent with triggered activity and abnormal automaticity. (PACE 2013; 36:e7–e10)