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.     

Determination of urinary lithogenic parameters in murine models orthologous to autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD), a genetic disease caused by mutations in PKD1 or PKD2 genes, is associated with a high prevalence of nephrolithiasis. The underlying mechanisms may encompass structural abnormalities resulting from cyst growth, urinary metabolic abnormalities or both. An increased frequency of hypocitraturia has been described in ADPKD even in the absence of nephrolithiasis, suggesting that metabolic alterations may be associated with ADPKD per se. We aimed to investigate whether non-cystic Pkd1-haploinsufficient (Pkd1 ^+/?) and/or nestin-Cre Pkd1-targeted cystic (Pkd1 ^cond/cond:Nestin^cre) mouse models develop urinary metabolic abnormalities potentially related to nephrolithiasis in ADPKD. 24-h urine samples were collected during three non-consecutive days from 10–12 and 18–20 week-old animals. At 10–12 weeks of age, urinary oxalate, calcium, magnesium, citrate and uric acid did not differ between test and their respective control groups. At 18–20 weeks, Pkd1 ^+/? showed slightly but significantly higher urinary uric acid vs. controls while cystic animals did not. The absence of hypocitraturia, hyperoxaluria and hyperuricosuria in the cystic model at both ages and the finding of hyperuricosuria in the 18–20 week-old animals suggest that anatomic cystic distortions per se do not generate the metabolic disturbances described in human ADPKD-related nephrolithiasis, while Pkd1 haploinsufficiency may contribute to this phenotype in this animal model.     

Simplified estimates of ion-activity products of calcium oxalate and calcium phosphate in mouse urine

This study aimed at formulating simplified estimates of ion-activity products of calcium oxalate (AP(CaOx)) and calcium phosphate (AP(CaP)) in mouse urineto find the most important determinants in order to limit the analytical work-up. Literature data on mouse urine composition was used to determine the relative effect of each urine variable on the two ion-activity products. AP(CaOx) and AP(CaP) were calculated by iterative approximation with the EQUIL2 computerized program. The most important determinants for AP(CaOx) were calcium, oxalate and citrate and for AP(CaP) calcium, phosphate, citrate, magnesium and pH. Urine concentrations of the variables were used. A simplified estimate of AP(CaOx) (AP(CaOx)-index(MOUSE)) that numerically approximately corresponded to 10(8) × AP(CaOx) was given the following expression:[Formula: see text]For a series of urine samples with various composition the coefficient of correlation between AP(CaOx)-index(MOUSE) and 10(8) × AP(CaOx) was 0.99 (p = 0.00000). A similar estimate of AP(CaP) (AP(CaP)-index(MOUSE)) was formulated so that it approximately would correspond numerically to 10(14) × AP(CaP) taking the following form:[Formula: see text]For a series of variations in urine composition the coefficient of correlation was 0.95 (p = 0.00000). The two approximate estimates shown in this article are simplified expressions of AP(CaOx) and AP(CaP). The intention of these theoretical calculations was not to get methods for accurate information on the saturation levels in urine, but to have mathematical tools useful for rough conclusions on the outcome of different experimental situations in mice. It needs to be emphasized that the accuracy will be negatively influenced if urine variables not included in the formulas differ very much from basic concentrations.     

Atheroablation with the Kensey catheter: a pathologic study

The mode of action of the Kensey catheter, a new atheroablation device, was investigated. Fresh above-the-knee amputated legs were used for recanalization of the superficial femoral artery. The variables used were identical to those of clinical trials, including a rotational speed of 50,000 rpm and an injection rate of 40 mL/min. The debris produced by the catheter was studied cytologically, and the arterial segments were examined histologically. The particle size in the debris ranged from 1 to 2,000 microns. The softer plaques produced a fine fibrin dust background with long strips of intima ranging from 10 to 2,000 microns. Complicated calcified plaques produced larger background material (10-120 microns) but smaller strips of intima (50-800 microns). Dissections and perforations occurred. Some of the debris produced by the atheroablation process was used to embolize a canine heart and kidney. Small focal infarctions were found in the heart, and large and multiple infarcts were seen in the kidney. In clinical studies the debris appears to be tolerated in the lower extremities. Its safety in the kidney and heart are questioned.     

p38 MAPK对嗜酸性粒细胞和支气管上皮细胞共培养时细胞因子释放的调控作用

目的 了解嗜酸性粒细胞和支气管上皮细胞相互作用诱导细胞因子释放的p38 MAPK信号转导通路.方法 用CD16磁珠抗体分离外周血中嗜酸性粒细胞,以嗜酸性粒细胞和支气管上皮细胞(BEAS-2B)接触共培养为实验模型,观察SB 203580对细胞培养上清液中细胞因子浓度的影响.细胞因子浓度采用ELISA和流式细胞微珠方法测定.结果 SB 203580能够有效抑制BEAS-2B细胞释放IL-6、IL-8(P＜0.05)和嗜酸性粒细胞释放IL-8(P＜0.01).SB 203580对嗜酸性粒细胞与BEAS-2B细胞接触共培养诱导的IL-6、IL-8和IP-10释放具有显著抑制作用(P＜0.001).结论 嗜酸性粒细胞、BEAS-2B细胞单独或相互作用时均通过p38 MAPK信号转导通路释放细胞因子.     

Giant Asian honeybee or Bambara stings causing myocardial infarction,bowel gangrene and fatal anaphylaxis in Sri Lanka: a case series

The sting of Giant Asian honeybee (Apis dorsata) or Bambara in Sinhala and Karunge Kulavi in Tamil is a common environmental hazard in Sri Lanka known to cause immediate allergic reactions, which could be fatal in sensitized individuals. We reported myocardial infarction, bowel gangrene and fatal anaphylaxis in a prospectively proven case series and the association of these uncommon complications with delayed removal of stingers from the patients' skin.     

Tryptophan 650 of human granulocyte colony-stimulating factor (G-CSF) receptor, implicated in the activation of JAK2, is also required for G- CSF-mediated activation of signaling complexes of the p21ras route

Granulocyte colony-stimulating factor (G-CSF) induces rapid phosphorylation of JAK kinases as well as activation of the p21ras route through interaction with its specific receptor (G-CSF-R). The cytoplasmic membrane-proximal region of G-CSF-R (amino acids 631 to 684) is necessary for proliferation induction and activation of JAK2. In contrast, activation of Shc and Syp, signaling molecules implicated in the p21ras signaling route, depends on the phosphorylation of tyrosine residues located in the membrane-distal region (amino acids 685 to 813) of G-CSF-R. We investigated whether G-CSF-induced activation of signaling complexes of the p21ras route depends on the function of the membrane-proximal cytoplasmic region of G-CSF-R. A G- CSF-R mutant was constructed in which tryptophan 650 was replaced by arginine and expressed in BAF3 cells (BAF/W650R). In contrast to BAF3 cell transfectants expressing wild-type G-CSF-R, BAF/W650-R cells did not proliferate and did not show activation of JAK2, STAT1, or STAT3 in response to G-CSF. Immunoprecipitations with anti-Shc and anti-Grb2 antisera showed that mutant W650R also failed to activate Syp and Shc. These data indicate that the membrane-proximal cytoplasmic domain of G- CSF-R is not only crucial for proliferative signaling and activation of JAK2 and STATs, but is also required for activation of the p21ras route, which occurs via the membrane-distal region of G-CSF-R.     

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.     

Ablating the Imperceptible: A Novel Application of Para‐Hisian Pacing

In some elderly patients with atrial fibrillation, especially in combination with heart failure, a rate control strategy may be preferred. When pharmacological therapy is ineffective or not tolerated, it is reasonable to perform atrioventricular (AV) node ablation with ventricular pacing. We describe a case in which this approach was necessary for management. However, the presence of periprocedural, drug‐induced AV block just before ablation provided a unique and challenging circumstance. We discuss the steps taken to ensure a successful procedure.