Residual neuromuscular blockade in the ICU: a prospective observational study and national survey.

Residual neuromuscular blockade is associated with significant morbidity. It has been widely studied in anaesthesia; however, the incidence of residual neuromuscular blockade in patients managed in the ICU is unknown. We conducted a prospective observational study in a tertiary ICU to determine the incidence of residual neuromuscular blockade using quantitative accelerographic monitoring. We tested for residual neuromuscular blockade (defined as a train-of-four ratio < 0.9) before cessation of sedation in anticipation of tracheal extubation. We also surveyed 16 other ICUs in New Zealand to determine their use of neuromuscular monitoring. A total of 191 patients were included in the final analysis. The incidence (95%CI) of residual neuromuscular blockade was 43% (36-50%), with a similar incidence observed in non-postoperative and postoperative patients. There was a lower risk of residual neuromuscular blockade with atracurium than rocuronium (risk ratio (95%CI) of 0.39 (0.12-0.78)) and a higher risk with pancuronium than rocuronium (1.59 (1.06-2.49)). Our survey shows that, in New Zealand ICUs, monitoring of neuromuscular function is rarely carried out before tracheal extubation. When neuromuscular monitoring is undertaken, it is based on individual clinician suspicion and performed using qualitative measurements. No ICU reported using a quantitative monitor or a clinical guideline. The results demonstrate a high incidence of residual neuromuscular blockade in our ICU patients and identify the type of neuromuscular blocking drug as a possible risk factor. Monitoring neuromuscular function before tracheal extubation is not currently the standard of care in New Zealand ICUs. These data suggest that residual neuromuscular blockade may be an under-recognised problem in ICU practice.

Survival of Clostridioides difficile spores in thermal and chemo-thermal laundering processes and influence of the exosporium on their adherence to cotton bed sheets.

Clostridioides difficile spores were previously demonstrated to survive industrial laundering. Understanding interactions between heat, disinfectants and soiling (e.g. bodily fluids) affecting C. difficile spore survival could inform the optimization of healthcare laundry processes. Reducing spore attachment to linen could also enhance laundering efficacy. This study aimed to compare the sensitivity of C. difficile spores to heat and detergent, with and without soiling and to investigate adherence to cotton. Survival of C. difficile spores exposed to industrial laundering temperatures (71-90°C), reference detergent and industrial detergent was quantified with and without soiling. The adherence to cotton after 0 and 24 h air drying was determined with the exosporium of C. difficile spores partially or fully removed. Clostridioides difficile spores were stable at 71°C for 20 min (≤0·37 log10 reduction) while 90°C was sporicidal (3 log10 reduction); soiling exerted a protective effect. Industrial detergent was more effective at 71°C compared to 25°C (2·81 vs 0·84 log10 reductions), however, specifications for sporicidal activity (>3 log10 reduction) were not met. Clostridioides difficile spores increasingly adhered to cotton over time, with 49% adherence after 24 h. Removal of the exosporium increased adherence by 19-23% compared to untreated spores. Further understanding of the role of the exosporium in attachment to cotton could enhance spore removal and aid decontamination of linen.

PAI-1 gain-of-function genotype, factors increasing PAI-1 levels, and airway obstruction: The GALA II Cohort.

BACKGROUND: PAI-1 gain-of-function variants promote airway fibrosis and are associated with asthma and with worse lung function in subjects with asthma. OBJECTIVE: We sought to determine whether the association of a gain-of-function polymorphism in plasminogen activator inhibitor-1 (PAI-1) with airway obstruction is modified by asthma status, and whether any genotype effect persists after accounting for common exposures that increase PAI-1 level. METHODS: We studied 2070 Latino children (8-21y) with genotypic and pulmonary function data from the GALA II cohort. We estimated the relationship of the PAI-1 risk allele with FEV1/FVC by multivariate linear regression, stratified by asthma status. We examined the association of the polymorphism with asthma and airway obstruction within asthmatics via multivariate logistic regression. We replicated associations in the SAPPHIRE cohort of African Americans (n=1056). Secondary analysis included the effect of the at-risk polymorphism on postbronchodilator lung function. RESULTS: There was an interaction between asthma status and the PAI-1 polymorphism on FEV1 /FVC (P=.03). The gain-of-function variants, genotypes (AA/AG), were associated with lower FEV1 /FVC in subjects with asthma (ß=-1.25, CI: -2.14,-0.35, P=.006), but not in controls. Subjects with asthma and the AA/AG genotypes had a 5% decrease in FEV1 /FVC (P<.001). In asthmatics, the risk genotype (AA/AG) was associated with a 39% increase in risk of clinically relevant airway obstruction (OR=1.39, CI: 1.01, 1.92, P=.04). These associations persisted after exclusion of factors that increase PAI-1 including tobacco exposure and obesity. CONCLUSIONS AND CLINICAL RELEVANCE: The decrease in the FEV1 /FVC ratio associated with the risk genotype was modified by asthma status. The genotype increased the odds of airway obstruction by 75% within asthmatics only. As exposures known to increase PAI-1 levels did not mitigate this association, PAI-1 may contribute to airway obstruction in the context of chronic asthmatic airway inflammation.

A large animal model that recapitulates the spectrum of human intervertebral disc degeneration.

OBJECTIVE: The objective of this study was to establish a large animal model that recapitulates the spectrum of intervertebral disc degeneration that occurs in humans and which is suitable for pre-clinical evaluation of a wide range of experimental therapeutics. DESIGN: Degeneration was induced in the lumbar intervertebral discs of large frame goats by either intradiscal injection of chondroitinase ABC (ChABC) over a range of dosages (0.1U, 1U or 5U) or subtotal nucleotomy. Radiographs were used to assess disc height changes over 12 weeks. Degenerative changes to the discs and endplates were assessed via magnetic resonance imaging (MRI), semi-quantitative histological grading, microcomputed tomography (µCT), and measurement of disc biomechanical properties. RESULTS: Degenerative changes were observed for all interventions that ranged from mild (0.1U ChABC) to moderate (1U ChABC and nucleotomy) to severe (5U ChABC). All groups showed progressive reductions in disc height over 12 weeks. Histological scores were significantly increased in the 1U and 5U ChABC groups. Reductions in T2 and T1ρ, and increased Pfirrmann grade were observed on MRI. Resorption and remodeling of the cortical boney endplate adjacent to ChABC-injected discs also occurred. Spine segment range of motion (ROM) was greater and compressive modulus was lower in 1U ChABC and nucleotomy discs compared to intact. CONCLUSIONS: A large animal model of disc degeneration was established that recapitulates the spectrum of structural, compositional and biomechanical features of human disc degeneration. This model may serve as a robust platform for evaluating the efficacy of therapeutics targeted towards varying degrees of disc degeneration.

Comparison of bacterial attachment to platelet bags with and without preconditioning with plasma.

BACKGROUND AND OBJECTIVES: Canadian Blood Services produces apheresis and buffy coat pooled platelet concentrates (PCs) stored in bags produced by two different manufacturers (A and B, respectively), both made of polyvinyl chloride-butyryl trihexyl citrate. This study was aimed at comparing Staphylococcus epidermidis adhesion to the inner surface of both bag types in the presence or absence of plasma factors. MATERIALS AND METHODS: Sets (N = 2-6) of bags type A and B were left non-coated (control) or preconditioned with platelet-rich, platelet-poor or defibrinated plasma (PRP, PPP and DefibPPP, respectively). Each bag was inoculated with a 200-ml S. epidermidis culture adjusted to 0·5 colony-forming units/ml. Bags were incubated under platelet storage conditions for 7 days. After culture removal, bacteria attached to the plastic surface were either dislodged by sonication for bacterial quantification or examined in situ by scanning electron microscopy (SEM). RESULTS: Higher bacterial adhesion was observed to preconditioned PC bags than control containers for both bag types (P < 0·0001). Bacterial attachment to preconditioned bags was confirmed by SEM. Bacteria adhered equally to both types of containers in the presence of PRP, PPP and DefibPPP residues (P > 0·05). By contrast, a significant increase in bacterial adherence was observed to type A bags compared with type B bags in the absence of plasma (P < 0·05) [Correction added on 16 June 2017, after first online publication: this sentence has been corrected]. CONCLUSION: The ability of S. epidermidis to adhere to preconditioned platelet collection bags depends on the presence of plasma factors. Future efforts should be focused on reducing plasma proteins' attachment to platelet storage containers to decrease subsequent bacterial adhesion.

Opportunity for interprofessional collaborative care-findings from a sample of federally qualified health center patients in the Midwest.

OBJECTIVES: Federally qualified health centers (FQHCs) frequently serve more socio-economically disadvantaged populations; existing literature suggests that underserved groups are more likely to experience various chronic physical and mental health conditions. FQHC patients may have significant needs for various specialty services that are beyond common FQHC providers. This study examines chronic condition prevalence, healthcare satisfaction, and use of multiprovider services in a Midwest FQHC patient population. We also evaluated the potential of interprofessional collaborative practices in FQHC settings. STUDY DESIGN: Cross-sectional study. METHODS: A total of 232 participants were recruited prior to or immediately after their scheduled clinic visit within an FQHC located on the fringes of an urban area. Respondents were invited to complete a brief questionnaire and grant access to their electronic medical records. RESULTS: Nearly half of participants were covered by Medicaid, private insurance carriers (19.4%), or Medicare (17.7%). The most prevalent chronic conditions included diabetes, depression, anxiety, and chronic pain. Almost half (46.6%) of participants were seen by two or three providers; 20% had 7+ office visits in the last year. While 35.3% reported health dissatisfaction, 30.6% reported health satisfaction. When asked if they were satisfied with their health care, nearly 70% reported satisfaction with health care, while only 4.7% reported healthcare dissatisfaction. CONCLUSIONS: The authors of this study recommend an interprofessional collaborate healthcare model be explored to address the complex and multifaceted healthcare needs of this population. Future research in this area should prospectively examine the utility of monitoring patient satisfaction in a collaborative practice setting.

Functional consequences of glucose and oxygen deprivation on engineered mesenchymal stem cell-based cartilage constructs.

OBJECTIVE: Tissue engineering approaches for cartilage repair have focused on the use of mesenchymal stem cells (MSCs). For clinical success, MSCs must survive and produce extracellular matrix in the physiological context of the synovial joint, where low nutrient conditions engendered by avascularity, nutrient utilization, and waste production prevail. This study sought to delineate the role of microenvironmental stressors on MSC viability and functional capacity in three dimensional (3D) culture. DESIGN: We evaluated the impact of glucose and oxygen deprivation on the functional maturation of 3D MSC-laden agarose constructs. Since MSC isolation procedures result in a heterogeneous cell population, we also utilized micro-pellet culture to investigate whether clonal subpopulations respond to these microenvironmental stressors in a distinct fashion. RESULTS: MSC health and the functional maturation of 3D constructs were compromised by both glucose and oxygen deprivation. Importantly, glucose deprivation severely limited viability, and so compromised the functional maturation of 3D constructs to the greatest extent. The observation that not all cells died suggested there exists heterogeneity in the response of MSC populations to metabolic stressors. Population heterogeneity was confirmed through a series of studies utilizing clonally derived subpopulations, with a spectrum of matrix production and cell survival observed under conditions of metabolic stress. CONCLUSIONS: Our findings show that glucose deprivation has a significant impact on functional maturation, and that some MSC subpopulations are more resilient to metabolic challenge than others. These findings suggest that pre-selection of subpopulations that are resilient to metabolic challenge may improve in vivo outcomes.

APC promoter 1B deletion in seven American families with familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is a colorectal cancer predisposition syndrome caused by mutations in the adenomatous polyposis coli (APC) gene. Clinical genetic testing fails to identify disease causing mutations in up to 20% of clinically apparent FAP cases. Following the inclusion of multiplex ligation-dependent probe amplification (MLPA) probes specific for APC promoter 1B, seven probands were identified with a deletion of promoter 1B. Using haplotype analysis spanning the APC locus, the seven families appear to be identical by descent from a common founder. The clinical phenotype of 19 mutation carriers is classical FAP with colectomy at an average age of 24. The majority of cases had a large number of duodenal and gastric polyps. Measurements of allele-specific expression of APC mRNA using TaqMan assay confirmed that relative expression in the allele containing the promoter 1B deletion was reduced 42-98%, depending on tissue type. This study confirms the importance of APC promoter deletions as a cause of FAP and identifies a founder mutation in FAP patients from the United States.

A plasmin-activatable thrombin inhibitor reduces experimental thrombosis and assists experimental thrombolysis in murine models.

The leech protein hirudin is a potent natural thrombin inhibitor. Its potential as an antithrombotic agent is limited by its promotion of bleeding. We attempted to modify this profile by positioning albumin and a plasmin cleavage site on its N-terminus, in recombinant protein HSACHV3 [comprising hirudin variant 3 (HV3) fused to the C-terminus of human serum albumin (HSA) via a plasmin cleavage site (C)], Previously we showed that HSACHV3 inhibited thrombin in a plasmin-dependent manner, and that, unlike HV3, it did not increase bleeding in vivo when administered to mice. Here we tested HSACHV3 for the ability to reduce thrombosis and assist enzymatic thrombolysis in animal models. Intravenous administration of HSACHV3, but not a control protein lacking the plasmin cleavage site (HSAHV3), reduced thrombus weight by 2.1-fold in the ferric chloride-injured mouse vena cava. Similarly, thrombi formed in a rabbit jugular vein stasis model were 1.7-fold lighter in animals treated with HSACHV3 compared to those receiving HSAHV3. Administration of 60 mg/kg body weight HSACHV3 prolonged the time to occlusion in the ferric chloride-injured mouse carotid artery by threefold compared to vehicle controls, while equimolar HSAHV3 had no effect. HSACHV3 had no ability to restore flow to the murine carotid arteries occluded by ferric chloride treatment, but combining HSACHV3 (60 mg/kg) with recombinant mutant tissue plasminogen activator (TNKase) significantly reduced the time to restore patency to the artery compared to TNKase alone. Unlike unfused HV3, HSACHV3 did not increase bleeding in a mouse liver laceration model. Our results show that HSACHV3 acts as an antithrombotic agent that does not promote bleeding and which speeds the time to flow restoration when used as an adjunct to pharmacological thrombolysis in animal models.

Lung spirometry parameters and diffusion capacity are decreased in patients with Type 2 diabetes.

AIMS: In cohort studies, Type 2 diabetes mellitus has been associated with decreased forced 1 s expiratory volume and forced vital capacity. We examined if forced vital capacity, forced 1 s expiratory volume and diffusion lung capacity correlate with diabetes mellitus across different races in a clinical setting. METHODS: We examined the medical records of 19,882 adults 18-97 years of age in our centre from 1 January 2000 to 1 May 2009. After excluding patients with diseases causing abnormal lung function, 4164 subjects were available for analysis. We used multiple linear regressions to examine cross-sectional differences in forced vital capacity, forced 1 s expiratory volume and carbon monoxide diffusing capacity between patients with and without diabetes mellitus, after adjustment for age, sex, race, height, smoking, BMI and heart failure. RESULTS: Patients with diabetes (n = 560) were older (62 ± 12 vs. 55 ± 16 years), more likely to be men (56 vs. 43%), overweight (BMI 31.7 ± 8.5 vs. 27.3 ± 6.7 kg/m2 ), have heart failure (33 vs. 14%) and less likely to be Caucasians (65 vs. 76%) and never smokers (66 vs. 72%) compared with patients without diabetes (n = 3604). The mean unadjusted values in patients with diabetes vs. those without were: forced vital capacity 2.78 ± 0.91 vs. 3.19 ± 1.03 l; forced 1 s expiratory volume 2.17 ± 0.74 vs. 2.49 ± 0.0.83; and carbon monoxide diffusing capacity 16.67 ± 5.53 vs. 19.18 ± 6.72 ml(-1) min(-1) mmHg, all P < 0.0001. These differences remained significant after adjustment for covariates. After race stratification, only Caucasians with diabetes had a significant decrease in all lung function measures. CONCLUSIONS: Patients with diabetes have decreased lung function compared with those without diabetes. Caucasians with diabetes have more global lung function impairment compared with African-Americans and Hispanics.

Relationship between prenatal lead exposure and infant blood lead levels.

Recent literature has shown that analyzing newborn dried blood spots (DBS) may be effective in assessing some prenatal environmental exposures, such as exposure to lead. The purpose of this study was to evaluate the relationship between prenatal exposure to lead (as measured by newborn DBS results) and blood lead levels (BLLs) in infants 6 months of age or younger, using public health registry data for infants born in Texas from July 2002 through July 2006. The Texas Child Lead Registry (TCLR) was used to identify infants with documented elevated BLLs of 10 µg/dL or higher as well as infants with documented low BLLs. BLLs for these children were compared to their corresponding newborn DBS results using Pearson correlation coefficients and exact logistic regression models. Overall, a significant but weak positive correlation was found between infant BLLs and corresponding newborn DBS lead levels (r = 0.48). However, the odds of an infant with an elevated newborn DBS lead level having an elevated BLL at 6 months of age or younger were much greater than for an infant with a low newborn DBS lead level of <5 µg/dL (adjusted odds ratio 27.95, 95% CI: 5.52-277.28). Although an association was observed between newborn DBS lead levels and BLLs in infants tested between 0 to 6 months of age, our findings suggest that prenatal exposure may not be the only significant source of lead exposure for infants ≤6 months of age.

Lean mass predicts asthma better than fat mass among females.

The obesity phenotype associated with asthma is not known. Our objective was to define the relative contribution of various distributions of fat and lean mass to asthma prevalence. Data were obtained from 2,525 participants (including 1,422 females) who underwent dual-energy X-ray absorptiometry (DEXA) at the year 20 examination in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. Total, truncal, arm and leg distributions of fat and lean mass were adjusted to the person's height. Self-reported asthma was the outcome. Asthma among females was associated with greater total fat mass, arm fat mass, total lean mass, truncal lean mass and arm lean mass. Among males, none of these mass measures were significantly associated with asthma. Among females, the association with asthma was stronger for total lean mass than for total fat mass. Further, among various regional distributions of lean and fat mass in females, truncal lean mass was the strongest predictor. Total lean mass is more strongly associated with asthma than total fat mass among females. These findings are contrary to the popular perception that excess physiological fat drives the obesity-asthma association. Rather, we hypothesise that ectopic fat within the "lean" tissues drives this association among females.

Expression of the p53 oncogene in acute myeloblastic leukemia.

We have investigated whether the p53 oncogene is expressed in the blast cells of patients with acute myeloblastic leukemia. p53 protein was detected in the blast cells of 19 out of 34 patients, but not in normal myelopoietic cells. We find a highly significant correlation between p53 protein synthesis in leukemic blast cells and the secondary plating efficiency of these cells (p = 0.0001). The latter provides an estimate for the self renewal capacity of progenitor cells in the blast population. These data indicate that p53 may be involved in leukemic stem cell renewal.

Systematic review of the association between lung function and Type 2 diabetes mellitus.

AIMS: To describe the association between lung function and Type 2 diabetes mellitus. METHODS: We identified English language studies evaluating the association between lung function and diabetes mellitus in the MEDLINE database from 1 January 1975 to 31 December 2009. We evaluated study quality based on established criteria (54 studies were reviewed, 34 met the inclusion criteria). RESULTS: Cross-sectional studies showed that adults with diabetes mellitus have lower forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), with reductions in FVC more consistent than FEV1 and lower diffusion capacity (DLCO) compared with their non-diabetic counterparts. The reduced lung function in patients with diabetes is inversely related to blood glucose levels, duration of diabetes and its severity and is independent of smoking or obesity. Findings in cohort studies have been less consistent, with only a few studies identifying an increased rate of lung function decline in adults with diabetes. In addition, other cohort studies have reported an association between decreased lung function and incident insulin resistance and diabetes. Studies evaluating biological mechanisms to explain the association between lung impairment and diabetes identified microangiopathy of the alveolar capillaries and pulmonary arterioles, chronic inflammation, autonomic neuropathy involving the respiratory muscles, loss of elastic recoil secondary to collagen glycosylation of lung parenchyma, hypoxia-induced insulin resistance and low birthweight, as being associated with both insulin resistance and impaired lung function. CONCLUSIONS: There is an association between diabetes mellitus and decreased lung function, but the definitive direction as well as the exact pathophysiological mechanism to explain this association requires further investigation.

Are horses that undergo an exploratory laparotomy for correction of a right dorsal displacement of the large colon predisposed to post operative colic, compared to other forms of large colon displacement?

REASON FOR PERFORMING STUDY: It is a clinical impression that horses diagnosed with a right dorsal displacement (RDD) of the large colon, are more likely to suffer from recurrent episodes of colic post operatively, compared to other forms of nonstrangulating large colon displacement. OBJECTIVES: To investigate whether the type of nonstrangulating large colon displacement identified at exploratory laparotomy would influence long-term outcome. HYPOTHESIS: Horses identified with a RDD of the large colon at exploratory laparotomy would be more likely to experience recurrent episodes of post operative colic than other types of displacement. MATERIALS AND METHODS: Medical records for horses undergoing an exploratory laparotomy, from 2000-2008, for a nonstrangulating large colon displacement were reviewed. Data retrieved included: subject details, previous medical history, details of current episodes of colic, results of preoperative examination, surgical findings and procedures, post operative management and complications. Follow-up information was obtained by reference to computerised clinical records and by telephone questionnaire administered to the horse's owner or carer, and included details of any colic episodes exhibited by the horse after discharge and whether a repeat celiotomy had been required to resolve the colic episodes. RESULTS: There were 165 surgeries identified, in 154 horses. It was found that those horses with RDD were significantly more likely to experience recurrent episodes of colic requiring veterinary intervention post operatively compared to other types of displacement. CLINICAL RELEVANCE: Long-term prognosis and likelihood of post operative complications is an important consideration for both owners and veterinarians.

Bacterial culture of septic synovial structures of horses: does a positive bacterial culture influence prognosis?

REASONS FOR PERFORMING STUDY: The influence of synovial fluid culture on short- and long-term prognosis of cases with septic synovitis requires study. HYPOTHESES: Horses with a positive bacterial culture from septic synovial fluid are less likely to survive or return to successful athletic function than those with a negative bacterial culture from septic synovial fluid. METHODS: Records of mature horses presented to 2 equine referral hospitals for investigation of suspected septic synovitis were examined. Horses (n=206) were included in the study if synovial fluid was submitted for full laboratory examination, including bacterial culture. A diagnosis of septic synovitis was based on a nucleated cell count>30x10(9) cells/l or>90% neutrophils and other clinical, cytological and bacteriological parameters. Long-term follow-up was obtained by telephone questionnaire. Univariate analysis, using the Fisher's exact test, was used for all outcomes. RESULTS: Fourteen (20.9%) of 67 horses with a positive bacterial culture from synovial fluid were subjected to euthanasia because of persistent synovial sepsis compared to 2 (1.44%) of 139 with negative bacterial cultures (P<0.001). Overall survival and successful long-term return to function in horses with a positive bacterial culture was 50% (24/48 horses) compared to 70.5% (74/105) in culture negative horses (P=0.01). In horses that survived to be discharged, successful long-term return to function was not significantly different between culture positive and culture negative groups. Growth of Staphylococcus aureus from synovial fluid did not affect short-term survival to discharge from the hospital compared to other positive bacterial culture; however, successful long-term return to function was only 30.4% (4/13) in horses from which S. aureus was cultured compared to 73.9% (17/23) of horses in which other bacteria were cultured (P=0.015). CONCLUSIONS AND POTENTIAL CLINICAL RELEVANCE: Horses with a positive bacterial culture from a septic synovitis have a poorer prognosis for survival to discharge from hospital and overall long-term return to function than horses that yielded no bacterial growth. When S. aureus was cultured, the long-term prognosis was poorer.

Understanding protein folding via free-energy surfaces from theory and experiment.

The ability of protein molecules to fold into their highly structured functional states is one of the most remarkable evolutionary achievements of biology. In recent years, our understanding of the way in which this complex self-assembly process takes place has increased dramatically. Much of the reason for this advance has been the development of energy surfaces (landscapes), which allow the folding reaction to be described and visualized in a meaningful manner. Analysis of these surfaces, derived from the constructive interplay between theory and experiment, has led to the development of a unified mechanism for folding and a recognition of the underlying factors that control the rates and products of the folding process.

Activation of RyR2 by class I kinase inhibitors.

BACKGROUND AND PURPOSE: Kinase inhibitors are a common treatment for cancer. Class I kinase inhibitors that target the ATP-binding pocket are particularly prevalent. Many of these compounds are cardiotoxic and can cause arrhythmias. Spontaneous release of Ca2+ via cardiac ryanodine receptors (RyR2), through a process termed store overload-induced Ca2+ release (SOICR), is a common mechanism underlying arrhythmia. We explored whether class I kinase inhibitors could modify the activity of RyR2 and trigger SOICR to determine if this contributes to the cardiotoxic nature of these compounds. EXPERIMENTAL APPROACH: The impact of class I and II kinase inhibitors on SOICR was studied in HEK293 cells and ventricular myocytes using single-cell Ca2+ imaging. A specific effect on RyR2 was confirmed using single channel recordings. Ventricular myocytes were also used to determine if drug-induced changes in SOICR could be reversed using anti-SOICR agents. KEY RESULTS: Class I kinase inhibitors increased the propensity of SOICR. Single channel recording showed that this was due to a specific effect on RyR2. Class II kinase inhibitors decreased the activity of RyR2 at the single channel level but had little effect on SOICR. The promotion of SOICR mediated by class I kinase inhibitors could be reversed using the anti-SOICR agent VK-II-86. CONCLUSIONS AND IMPLICATIONS: Part of the cardiotoxicity of class I kinase inhibitors can be assigned to their effect on RyR2 and increase in SOICR. Compounds with anti-SOICR activity may represent an improved treatment option for patients.

Association between asthma and serum adiponectin concentration in women.

BACKGROUND: The association of murine asthma with adiposity may be mediated by adiponectin, an anti-inflammatory adipokine with reduced serum concentrations in obese subjects. A study was undertaken to examine whether the serum adiponectin concentration is associated with human asthma and whether it explains the association between adiposity and asthma, particularly in women and in premenopausal women. METHODS: A cross-sectional analysis was performed of 2890 eligible subjects at year 15 of the Coronary Artery Risk Development in Young Adults (CARDIA) cohort and its YALTA ancillary study who had either current asthma or never asthma at that evaluation. Obesity was defined as body mass index (BMI) >or=30 kg/m(2). Multivariable logistic regression analysis was performed with current asthma status as the dependent variable. RESULTS: Women, but not men, with current asthma had a lower mean unadjusted serum adiponectin concentration than those with never asthma (p<0.001; p for sex interaction <0.001). Similarly, current asthma was related to obesity only in women (OR 3.31, 95% CI 2.00 to 5.46, p for sex interaction = 0.004); this association was little affected by adjusting for serum adiponectin. The prevalence of current asthma in premenopausal women was reduced in the highest compared with the lowest tertile of serum adiponectin concentration (OR 0.46, 95% CI 0.26 to 0.84, p = 0.03), after adjusting for BMI. However, the interaction between serum adiponectin concentration and BMI category on current asthma status was not significant in premenopausal women or women overall. CONCLUSIONS: A high serum adiponectin concentration may protect against current asthma in premenopausal women but does not explain the association between asthma and adiposity.

A mechanism of benefit of soy genistein in asthma: inhibition of eosinophil p38-dependent leukotriene synthesis.

BACKGROUND: Dietary intake of the soy isoflavone genistein is associated with reduced severity of asthma, but the mechanisms responsible for this effect are unknown. OBJECTIVE: To determine whether genistein blocks eosinophil leukotriene C(4) (LTC(4)) synthesis and to evaluate the mechanism of this effect, and to assess the impact of a 4-week period of soy isoflavone dietary supplementation on indices of eosinophilic inflammation in asthma patients. METHODS: Human peripheral blood eosinophils were stimulated in the absence and presence of genistein, and LTC(4) synthesis was measured. 5-lipoxygenase (5-LO) nuclear membrane translocation was assessed by confocal immunofluorescence microscopy. Mitogen-activated protein (MAP) kinase activation was determined by immunoblot. Human subjects with mild-to-moderate persistent asthma and minimal or no soy intake were given a soy isoflavone supplement (100 mg/day) for 4 weeks. The fraction of exhaled nitric oxide (FE(NO)) and ex vivo eosinophil LTC(4) production were assessed before and after the soy isoflavone treatment period. RESULTS: Genistein inhibited eosinophil LTC(4) synthesis (IC(50) 80 nm), blocked phosphorylation of p38 MAP kinase and its downstream target MAPKAP-2, and reduced translocation of 5-LO to the nuclear membrane. In patients with asthma, following 4 weeks of dietary soy isoflavone supplementation, ex vivo eosinophil LTC(4) synthesis decreased by 33% (N=11, P=0.02) and FE(NO) decreased by 18% (N=13, P=0.03). CONCLUSION: At physiologically relevant concentrations, genistein inhibits eosinophil LTC(4) synthesis in vitro, probably by blocking p38- and MAPKAP-2-dependent activation of 5-LO. In asthma patients, dietary soy isoflavone supplementation reduces eosinophil LTC(4) synthesis and eosinophilic airway inflammation. These results support a potential role for soy isoflavones in the treatment of asthma.