Predictors of cycling performance success: Traditional approaches and a novel method to assess performance capacity in U23 road cyclists

OBJECTIVES

This study aimed to investigate predictors of cycling performance in U23 cyclists by comparing traditional approaches to a novel method - the compound score. Thirty male U23 cyclists (N = 30, age 20.1 ± 1.1 yrs, body mass 69.0 ± 6.9 kg, height 182.6 ± 6.2 cm, V̇O_2max 73.8 ± 2.5 mL·kg^-1·min^-1) participated in this study.

DESIGN

Power output information was derived from laboratory and field-testing during pre-season and mean maximal power outputs (MMP) from racing season. Absolute and relative 5-min MMP, 5-min MMP after 2000 kJ (MMP_{2000 kJ}), allometric scaling and the compound score were compared to the race score and podium (top 3) performance during a competitive season.

METHODS

Positive and negative predictive values were calculated for all significant performance variables for the likelihood of a podium performance.

RESULTS

The absolute 5-min MMP of the field test revealed the highest negative predictive capacity (82.4%, p = 0.012) for a podium performance. The compound score of the 5-min MMP_{2000 kJ} demonstrated the highest positive and average predictive capacity (83.3%, 78.0%, p = 0.007 - respectively). The multi-linear regression analysis revealed a significant predictive capacity between performance variables and the race score (R² = 0.55, p = 0.015).

CONCLUSIONS

Collectively the results of the present study reveal that the compound score, alongside absolute power, was able to predict the highest positive and average likelihood for a podium performance. These findings can help to better understand performance capacity from field data to predict future cycling success.

Multicenter, Prospective, Controlled, Before-and-After, Quality Improvement Study (Stroke123) of Acute Stroke Care

Supplemental Digital Content is available in the text.

Background and Purpose—

Hospital uptake of evidence-based stroke care is variable. We aimed to determine the impact of a multicomponent program involving financial incentives and quality improvement interventions, on stroke care processes.

Methods—

A prospective study of interventions to improve clinical care quality indicators at 19 hospitals in Queensland, Australia, during 2010 to 2015, compared with historical controls and 23 other Australian hospitals. After baseline routine audit and feedback (control phase, 30 months), interventions involving financial incentives (21 months) and then addition of externally facilitated quality improvement workshops with action plan development (9 months) were implemented. Postintervention phase was 13 months. Data were obtained for the analysis from a previous continuous audit in Queensland and subsequently the Australian Stroke Clinical Registry. Primary outcome: change in median composite score for adherence to ≤8 indicators. Secondary outcomes: change in adherence to self-selected indicators addressed in action plans and 4 national indicators compared with other Australian hospitals. Multivariable analyses with adjustment for clustered data.

Results—

There were 17 502 patients from the intervention sites (median age, 74 years; 46% women) and 20 484 patients from other Australian hospitals. Patient characteristics were similar between groups. There was an 18% improvement in the primary outcome across the study periods (95% CI, 12%–24%). The largest improvement was following introduction of financial incentives (14%; 95% CI, 8%–20%), while indicators addressed in action plans provided an 8% improvement (95% CI, 1%–17%). The national score (4 indicators) improved by 17% (95% CI, 13%–20%) versus 0% change in other Australian hospitals (95% CI, −0.03 to 0.03). Access to stroke units improved more in Queensland than in other Australian hospitals (P<0.001).

Conclusions—

The quality improvement interventions significantly improved clinical practice. The findings were primarily driven by financial incentives, but were also contributed to by the externally facilitated, quality improvement workshops. Assessment in other regions is warranted.

Responding to Mycobacterium chimaera heater-cooler unit contamination: international and national intersectoral collaboration coordinated in the state of Queensland, Australia

BACKGROUND

The index case of Mycobacterium chimaera infection in a patient following open cardiac surgery in the state of Queensland, Australia prompted a centralized coordinated response to mitigate the risk.

AIM

To describe the public health response to M. chimaera contamination of heater-cooler units (HCUs) and patient infection.

METHODS

A public health sector strategy was developed with national and international consultation to respond to the threat of HCUs contaminated with M. chimaera. Data linkage of non-tuberculous mycobacterium notifications and selected procedures was undertaken where potential use of HCUs was identified through hospitalization records. Water sampling and testing protocols were standardized. Public disclosure and patient notification were undertaken.

FINDINGS

A single case of disseminated M. chimaera infection in a patient has been diagnosed to date in Queensland, Australia. Ten of 12 (83%) LivaNova Stockert 3T HCUs from five hospitals tested positive for M. chimaera. In total, 5650 patients were notified by post of their potential risk of exposure. Use of the telehealth call centre was modest. M. chimaera was also found in extracorporeal membrane oxygenation heater units produced by two other device manufacturers, four of which tested positive prior to commissioning for use.

CONCLUSIONS

Rapid international collaboration optimized the Queensland Health response to potential M. chimaera exposure during cardiac surgery. State-wide collaboration ensured a transparent, consistent approach to contacting patients and informing the public of the potential risk. A framework for ongoing risk management, clinical awareness and laboratory diagnosis was established. No further cases of M. chimaera infection have been identified in Queensland.

Hyak mortality monitoring system: innovative sampling and estimation methods - proof of concept by simulation

Traditionally health statistics are derived from civil and/or vital registration. Civil registration in low- to middle-income countries varies from partial coverage to essentially nothing at all. Consequently the state of the art for public health information in low- to middle-income countries is efforts to combine or triangulate data from different sources to produce a more complete picture across both time and space - data amalgamation. Data sources amenable to this approach include sample surveys, sample registration systems, health and demographic surveillance systems, administrative records, census records, health facility records and others. We propose a new statistical framework for gathering health and population data - Hyak - that leverages the benefits of sampling and longitudinal, prospective surveillance to create a cheap, accurate, sustainable monitoring platform. Hyak has three fundamental components: Data amalgamation: A sampling and surveillance component that organizes two or more data collection systems to work together: (1) data from HDSS with frequent, intense, linked, prospective follow-up and (2) data from sample surveys conducted in large areas surrounding the Health and Demographic Surveillance System (HDSS) sites using informed sampling so as to capture as many events as possible;Cause of death: Verbal autopsy to characterize the distribution of deaths by cause at the population level; andSocioeconomic status (SES): Measurement of SES in order to characterize poverty and wealth. We conduct a simulation study of the informed sampling component of Hyak based on the Agincourt HDSS site in South Africa. Compared with traditional cluster sampling, Hyak's informed sampling captures more deaths, and when combined with an estimation model that includes spatial smoothing, produces estimates of both mortality counts and mortality rates that have lower variance and small bias.

Detecting signals in pharmacogenomic genome-wide association studies

In one common pharmacogenomic scenario, outcome measures are compared for treated and untreated subjects across genotype defined subgroups. The key question is whether treatment benefit (or harm) is particularly strong in certain subgroups, and therefore statistical analysis focuses on the interaction between treatment and genotype. However, genome-wide analysis in such scenarios requires careful statistical thought since, in addition to the usual problems of multiple testing, the marker-defined sample sizes, and therefore power, vary across the individual genotypes being evaluated. The variability in power means the usual practice of using a common p-value threshold across tests has difficulties. The reason is that the use of a fixed threshold, with variable power, implies that the costs of type I and type II errors are varying across tests in a manner which is implicit rather than dictated by the analyst. In this paper we discuss this problem and describe an easily implementable solution based on Bayes factors. We pay particular attention to the specification of priors, which is not a straightforward task. The methods are illustrated using data from a randomized controlled clinical trial in which homocysteine levels are compared in individuals receiving low and high doses of folate supplements and across marker subgroups. The method we describe is implemented in the R computing environment with code available from http://faculty.washington.edu/jonno/cv.html.

The treatment of stable paediatric forearm fractures using a cast that may be removed at home

We investigated whether, in the management of stable paediatric fractures of the forearm, flexible casts that can be removed at home are as clinically effective, cost-effective and acceptable to both patient and parent as management using a cast conventionally removed in hospital. A single-centre randomised controlled trial was performed on 317 children with a mean age of 9.3 years (2 to 16). No significant differences were seen in the change in Childhood Health Assessment Questionnaire index score (p = 0.10) or EuroQol 5-Dimensions domain scores between the two groups one week after removal of the cast or the absolute scores at six months. There was a significantly lower overall median treatment cost in the group whose casts were removed at home (£150.88 (sem 1.90) vs £251.62 (sem 2.68); p <  0.001). No difference was seen in satisfaction between the two groups (p = 0.48).

Cite this article: Bone Joint J 2013;95-B:1714–20.

Season is associated with Pseudomonas aeruginosa acquisition in young children with cystic fibrosis

Pseudomonas aeruginosa, the principal respiratory pathogen in cystic fibrosis (CF) patients, is ubiquitous in the environment. Initial P. aeruginosa isolates in CF patients are generally environmental in nature. However, little information regarding seasonality of P. aeruginosa acquisition is available. We conducted a retrospective study to evaluate the seasonality of initial P. aeruginosa acquisition in young children with CF in the USA using the Cystic Fibrosis Foundation National Patient Registry from 2003 to 2009. Additionally, we assessed whether seasonal acquisition varied by climate zone. A total of 4123 children met inclusion criteria and 45% (n = 1866) acquired P. aeruginosa during a mean 2.0 years (SD 0.2 years) of follow up. Compared with winter, increased P. aeruginosa acquisition was observed in summer (incidence rate ratio (IRR): 1.22; 95% CI: 1.07-1.40) and autumn (IRR: 1.34; 95% CI: 1.18-1.52), with lower acquisition observed in spring (IRR: 0.81; 95% CI: 0.70-0.94). Seasonal variations in P. aeruginosa acquisition rates in the temperate and continental climate zones were similar to those in the overall cohort. In contrast, no significant seasonal effect was observed in the dry climate zone. In a corresponding analysis, no seasonal difference was observed in the rate of acquisition of Staphylococcus aureus, another common CF respiratory pathogen. These results provide preliminary support that climatic factors may be associated with initial P. aeruginosa acquisition in CF patients. Investigation and identification of specific risk factors, as well as awareness of seasonal variation, could potentially inform clinical recommendations including increased awareness of infection control and prevention strategies.

A robust bayesian random effects model for nonlinear calibration problems

In the context of a bioassay or an immunoassay, calibration means fitting a curve, usually nonlinear, through the observations collected on a set of samples containing known concentrations of a target substance, and then using the fitted curve and observations collected on samples of interest to predict the concentrations of the target substance in these samples. Recent technological advances have greatly improved our ability to quantify minute amounts of substance from a tiny volume of biological sample. This has in turn led to a need to improve statistical methods for calibration. In this article, we focus on developing calibration methods robust to dependent outliers. We introduce a novel normal mixture model with dependent error terms to model the experimental noise. In addition, we propose a reparameterization of the five parameter logistic nonlinear regression model that allows us to better incorporate prior information. We examine the performance of our methods with simulation studies and show that they lead to a substantial increase in performance measured in terms of mean squared error of estimation and a measure of the average prediction accuracy. A real data example from the HIV Vaccine Trials Network Laboratory is used to illustrate the methods.

Marginal costs of hospital-acquired conditions: information for priority-setting for patient safety programmes and research

OBJECTIVE

To estimate the relative inpatient costs of hospital-acquired conditions.

METHODS

Patient level costs were estimated using computerized costing systems that log individual utilization of inpatient services and apply sophisticated cost estimates from the hospital's general ledger. Occurrence of hospital-acquired conditions was identified using an Australian 'condition-onset' flag for diagnoses not present on admission. These were grouped to yield a comprehensive set of 144 categories of hospital-acquired conditions to summarize data coded with ICD-10. Standard linear regression techniques were used to identify the independent contribution of hospital-acquired conditions to costs, taking into account the case-mix of a sample of acute inpatients (n = 1,699,997) treated in Australian public hospitals in Victoria (2005/06) and Queensland (2006/07).

RESULTS

The most costly types of complications were post-procedure endocrine/metabolic disorders, adding AU$21,827 to the cost of an episode, followed by MRSA (AU$19,881) and enterocolitis due to Clostridium difficile (AU$19,743). Aggregate costs to the system, however, were highest for septicaemia (AU$41.4 million), complications of cardiac and vascular implants other than septicaemia (AU$28.7 million), acute lower respiratory infections, including influenza and pneumonia (AU$27.8 million) and UTI (AU$24.7 million). Hospital-acquired complications are estimated to add 17.3% to treatment costs in this sample.

CONCLUSIONS

Patient safety efforts frequently focus on dramatic but rare complications with very serious patient harm. Previous studies of the costs of adverse events have provided information on 'indicators' of safety problems rather than the full range of hospital-acquired conditions. Adding a cost dimension to priority-setting could result in changes to the focus of patient safety programmes and research. Financial information should be combined with information on patient outcomes to allow for cost-utility evaluation of future interventions.

NRF2 Oxidative Stress Induced by Heavy Metals is Cell Type Dependent

Exposure to metallic environmental toxicants has been demonstrated to induce a variety of oxidative stress responses in mammalian cells. The transcription factor Nrf2 is activated in response to oxidative stress and coordinates the expression of antioxidant gene products. In this study, we describe the development of an Nrf2-specific reporter gene assay that can be used to study the oxidative stress response in multiple cell types. Using five different cell lines, the Nrf2-activating potency of twenty metals was assessed across a range of concentrations. While ten of the metals tested (cadmium, cobalt, copper, gold, iron, lead, mercury, silver, sodium arsenite and zinc) stimulated Nrf2-dependent transcriptional activity in at least three of the engineered cell lines, only three (cadmium, copper and sodium arsenite) were active in all five cell lines. A comparison of metal-induced Nrf2 transcriptional activation revealed significant differences in the absolute magnitude of activation as well as the relative potencies between the cell lines tested. However, there was no direct correlation between activity and potency. Taken together, these results show that the capacity to stimulate Nrf2 activity and relative potencies of these test compounds are highly dependent on the cell type tested. Since oxidative stress is thought to be involved in the mode of action of many toxicological studies, this observation may inform the design of paradigms for toxicity testing for toxicant prioritization and characterization.

Integrative health coaching for patients with type 2 diabetes: a randomized clinical trial

PURPOSE

The purpose of this study was to evaluate the effectiveness of integrative health (IH) coaching on psychosocial factors, behavior change, and glycemic control in patients with type 2 diabetes.

METHODS

Fifty-six patients with type 2 diabetes were randomized to either 6 months of IH coaching or usual care (control group). Coaching was conducted by telephone for fourteen 30-minute sessions. Patients were guided in creating an individualized vision of health, and goals were self-chosen to align with personal values. The coaching agenda, discussion topics, and goals were those of the patient, not the provider. Preintervention and postintervention assessments measured medication adherence, exercise frequency, patient engagement, psychosocial variables, and A1C.

RESULTS

Perceived barriers to medication adherence decreased, while patient activation, perceived social support, and benefit finding all increased in the IH coaching group compared with those in the control group. Improvements in the coaching group alone were also observed for self-reported adherence, exercise frequency, stress, and perceived health status. Coaching participants with elevated baseline A1C (>/=7%) significantly reduced their A1C.

CONCLUSIONS

A coaching intervention focused on patients' values and sense of purpose may provide added benefit to traditional diabetes education programs. Fundamentals of IH coaching may be applied by diabetes educators to improve patient self-efficacy, accountability, and clinical outcomes.

Practising Open Disclosure: clinical incident communication and systems improvement

This article explores the way that professionals are being inducted into articulating apologies to consumers of their services, in this case clinicians apologising to patients. The article focuses on the policy of Open Disclosure that is being adopted by health care organisations in the US, Canada, the UK and Australia and other nations. Open Disclosure policy mandates 'open discussion of clinical incidents' with patient victims. In Australia, Open Disclosure policy implementation is currently being complemented by intensive staff training, involving simulation of apology scenarios with actor-patients. The article presents an analysis of data collected from such training sessions. The analysis shows how simulated apologising engages frontline staff in evaluating the efficacy of their disclosures, and how staff may thereby be inducted into reconciling their affective and reflexive sensibilities with their organisational and professional responsibilities, and thereby produce the required organisational apology. The article concludes that Open Disclosure, besides potentially relaxing tensions between clinicians and consumers, may also affect how staff experience and enact their role in the overall system of health care organisation.

Geographic-based ecological correlation studies using supplemental case-control data

It is well known that the ecological study design suffers from a variety of biases that render the interpretation of its results difficult. Despite its limitations, however, the ecological study design is still widely used in a range of disciplines. The only solution to the ecological inference problem is to supplement the aggregate data with individual-level data and, to this end, Haneuse and Wakefield (Biometrics 2007; 63:128-136) recently proposed a hybrid study design in which an ecological study is supplemented with a sample of case-control data. The latter provides the basis for the control of bias, while the former may provide efficiency gains. Building on that work, we illustrate the use of the hybrid design in the context of a geographical correlation study of lung cancer mortality from the state of Ohio. Focusing on epidemiological applications, we initially provide an overview of the use of ecological studies in scientific research, highlighting the breadth of current application as well as advantages and drawbacks of the design. We consider the interplay between the two sources of information in the design: ecological and case-control, and then provide details on a Bayesian spatial random effects model in the setting of the hybrid design. Issues of specification are addressed, as well as sensitivity to modeling assumptions. Further, an interesting feature of these data is that they provide an example of how the proposed design may be used to resolve the ecological fallacy.

Activation of the unfolded protein response by deltaF508 CFTR

Environmental insults and misfolded proteins cause endoplasmic reticulum (ER) stress and activate the unfolded protein response (UPR). The UPR decreases endogenous cystic fibrosis transmembrane conductance regulator (CFTR) mRNA levels and protein maturation efficiency. Herein, we investigated the effects of the folding-deficient deltaF508 CFTR on ER stress induction and UPR activation. For these studies, we developed and characterized stable clones of Calu3deltaF cells that express different levels of endogenous wild-type (WT) and recombinant deltaF508 CFTR. We also present a novel RT-PCR-based assay for differential quantification of wild-type CFTR mRNA in the presence of deltaF508 CFTR message. The assay is based on a TaqMan minor groove binding (MGB) probe that recognizes a specific TTT sequence (encoding phenylalanine at position 508 in human CFTR). The MGB probe is extremely specific and sensitive to changes in WT CFTR message levels. In RNA samples that contain both WT and deltaF508 CFTR mRNAs, measurement of WT CFTR mRNA levels (using the MGB probe) and total CFTR mRNA (using commercial primers) allowed us to calculate deltaF508 CFTR mRNA levels. The results indicate that overexpression of deltaF508 CFTR causes ER stress and activates the UPR. UPR activation precedes a marked decrease in endogenous WT CFTR mRNA expression. Furthermore, polarized airway epithelial cell lines are important tools in cystic fibrosis research, and herein we provide an airway epithelial model to study the biogenesis and function of WT and deltaF508 CFTR expressed within the same cell.

The interpretation of exposure effect estimates in chronic air pollution studies

In this article we consider the interpretation of regression parameters used to represent 'chronic' or 'long-term' air pollution exposure effects. Although scientific interest typically lies in understanding such effects at the level of the individual, studies have generally employed a semi-ecological design; outcomes and confounder information are collected on individuals while exposure is only available at the aggregate-or group-level. A precise interpretation of results from a semi-ecological design must take into account the aggregated nature, both spatial and temporal, of the exposure measure. The most common analysis approach for assessing chronic exposure effects has been within the Cox proportional hazards model framework; specific analyses are tailored to accommodate the shortcomings of the available exposure information. We revisit the underlying assumptions of the Cox model and discuss the implications of two common aspects of chronic effects studies: time-dependent exposures and time-varying effects. Focusing on the consequences of temporal aggregation of exposure, we show that an estimate obtained from a time-aggregated semi-ecological design can correspond to very different underlying time-varying exposure and risk scenarios. Further, distinguishing which of these is correct is not possible from the semi-ecological data alone. Our goal is to highlight some statistical issues faced by existing studies of chronic air pollution effects, and aid in the development and planning of future studies.

Endoplasmic reticulum stress and the unfolded protein response regulate genomic cystic fibrosis transmembrane conductance regulator expression

The unfolded protein response (UPR) is a cellular recovery mechanism activated by endoplasmic reticulum (ER) stress. The UPR is coordinated with the ER-associated degradation (ERAD) to regulate the protein load at the ER. In the present study, we tested how membrane protein biogenesis is regulated through the UPR in epithelia, using the cystic fibrosis transmembrane conductance regulator (CFTR) as a model. Pharmacological methods such as proteasome inhibition and treatment with brefeldin A and tunicamycin were used to induce ER stress and activate the UPR as monitored by increased levels of spliced XBP1 and BiP mRNA. The results indicate that activation of the UPR is followed by a significant decrease in genomic CFTR mRNA levels without significant changes in the mRNA levels of another membrane protein, the transferrin receptor. We also tested whether overexpression of a wild-type CFTR transgene in epithelia expressing endogenous wild-type CFTR activated the UPR. Although CFTR maturation is inefficient in this setting, the UPR was not activated. However, pharmacological induction of ER stress in these cells also led to decreased endogenous CFTR mRNA levels without affecting recombinant CFTR message levels. These results demonstrate that under ER stress conditions, endogenous CFTR biogenesis is regulated by the UPR through alterations in mRNA levels and posttranslationally by ERAD, whereas recombinant CFTR expression is regulated only by ERAD.

Establishment and characterization of a novel polarized MDCK epithelial cellular model for CFTR studies

F508del is the most common mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that is responsible for the genetic disease Cystic Fibrosis (CF). It results in a major failure of CFTR to traffic to the apical membrane of epithelial cells, where it should function as a chloride (Cl-) channel. Most studies on localization, processing and cellular trafficking of wild-type (wt) and F508del-CFTR have been performed in non-epithelial cells. Notwithstanding, polarized epithelial cells possess distinctly organized and regulated membrane trafficking pathways. We have used Madin-Darby canine kidney (MDCK) type II cells (proximal tubular cells which do not express endogenous CFTR) to generate novel epithelial, polarized cellular models stably expressing wt- or F508del-CFTR through transduction with recombinant lentiviral vectors. Characterization of these cell lines shows that wt-CFTR is correctly processed and apically localized, producing a cAMP-activated Cl- conductance. In contrast, F508del-CFTR is mostly detected in itsimmature form, localized intracellularly and producing only residual Cl- conductance. These novel cell lines constitute bona fide models and significantly improved resources to investigate the molecular mechanisms of polarized membrane traffic of wt- and F508del-CFTR in the same cellular background. They are also useful to identify/validate novel therapeutic compounds for CF.

Lentiviral vector-based models of amyloid pathology: from cells to animals

Lentiviral vectors are efficient tools for the introduction of genes into a wide range of established and primary cells in vitro, ex vivo, and in vivo, and also permit efficient transgenesis in a wide range of mammalian species. Our goals have been to apply the broad capabilities of the lentiviral vector system to AD research. Using a set of vectors expressing APP and PS1 genes, we demonstrated the efficiency and fidelity of the system for in vitro biochemical analyses of genes and pathways involved in plaque deposition. These analyses were performed in cell lines and in primary neuronal cultures, which have previously been difficult to use. The methods and tools described here are applicable to the study of effects of other genes and gene combinations on APP processing, including suppression of gene activity by delivering shRNAs. We have attempted to create local plaque pathology by stereotactic injection of APP and PS1 expressing vectors into mouse brains for use as a rapid model for plaque pathology that can be used in a broad range of mammals. No amyloid or preamyloid pathology has been detected over a six-month period; the possible reasons are discussed. Lastly, we have used the vectors to create transgenic rats expressing mutant APP and mutant PS1 and have obtained the first set of positive pups with more expected. The results presented here demonstrate the utility of Lentiviral vector-based approaches to the study of AD and other neurodegenerative diseases.

Failure of cAMP agonists to activate rescued deltaF508 CFTR in CFBE41o- airway epithelial monolayers

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-regulated chloride channel. Mutations in the CFTR gene result in cystic fibrosis (CF). The most common mutation, deltaF508, results in endoplasmic reticulum-associated degradation (ERAD) of CFTR. DeltaF508 CFTR has been described as a temperature-sensitive mutation that can be rescued following growth at 27 degrees C. In order to study the processing and function of wild-type and rescued deltaF508 CFTR at the cell surface under non-polarized and polarized conditions, we developed stable cell lines expressing deltaF508 or wild-type CFTR. CFBE41o- is a human airway epithelial cell line capable of forming high resistance, polarized monolayers when cultured on permeable supports, while HeLa cells are normally grown under non-polarizing conditions. Immunoprecipitation, cell surface biotinylation, immunofluorescence, and functional assays confirmed the presence of deltaF508 CFTR at the cell surface in both cell lines after incubating the cells for 48 h at 27 degrees C. However, stimulators of wild-type CFTR such as forskolin, beta2-adrenergic or A2B-adenosine receptor agonists failed to activate rescued deltaF508 CFTR in CFBE41o- monolayers. Rescued deltaF508 CFTR could be stimulated with genistein independent of pretreatment with cAMP signalling agonists. Interestingly, rescued deltaF508 CFTR in HeLa cells could be efficiently stimulated with either forskolin or genistein to promote Cl- transport. These results indicate that deltaF508 CFTR, when rescued in CFBE41o- human airway epithelial cells, is poorly responsive to signalling pathways known to regulate wild-type CFTR. Furthermore, the differences in rescue and activation of deltaF508 CFTR in the two cell lines suggest that cell-type specific differences in deltaF508 CFTR processing are likely to complicate efforts to identify potentiators and/or correctors of the deltaF508 defect.

Lentiviral mediated gene delivery to the anterior chamber of rodent eyes

PURPOSE

To study the in vivo efficiency of lentiviral vectors in delivering genes to the trabecular meshwork (TM) of rodent eyes.

METHODS

Lentiviral vectors were constructed using the elongation factor 1 alpha (EF-1alpha) promoter driving expression of the green fluorescent protein (GFP) gene. The viral construct was injected intracamerally through the peripheral cornea into the anterior chamber of live rodent eyes. Several variables were evaluated to determine the optimal conditions for TM cell transduction. These parameters included viral concentration, injection volume, needle rotation, and the modulation of anterior chamber current convections. Changes in intraocular pressures (IOPs) were monitored using a Tonopen XL. Signs of inflammation and corneal neovascularization were evaluated by slit lamp observation. Three weeks after injection, the eyes were enucleated and analyzed for GFP expression and distribution.

RESULTS

A single intracameral viral dose between 10(7) and 10(8) pfu produced a high and evenly distributed expression of GFP in the TM and corneal endothelial cells. The cornea remained clear and no signs of inflammation were present during the course of the experiment. Moreover, no significant changes in IOPs were observed.

CONCLUSIONS

A high transduction efficiency of TM and corneal endothelial cells can be effectively obtained after a single dose of recombinant lentivirus. The EF-1alpha promoter induces high expression of the reporter gene and is a reliable alternative to the CMV promoter when stable, long term expression is desired.

Inhibition of p53 by lentiviral mediated shRNA abrogates G1 arrest and apoptosis in retinal pigmented epithelial cell line

We silenced p53 gene expression in ARPE-19, a human retinal pigmented epithelial cell line using RNA interference. The effect of silencing the p53 gene in proliferating ARPE-19 cells was studied. Four short hairpin RNAs (shRNAs) targeting different regions of human p53 mRNA were delivered individually into ARPE-19 cells using lentiviral vector to produce stable cell lines. p53 mRNA and protein levels were reduced to varying extents in the four shRNA-transduced ARPE-19 cell lines. The cell line that showed greatest reduction (85-90%) of p53 expression showed decreased p21 promoter activation after DNA damage with camptothecin, etoposide and MMS. Whereas treatment of wild type ARPE-19 cells with camptothecin resulted in apoptosis, silencing p53 expression increased their survival. Cell cycle analyses indicated that irradiation resulted in a G(1) arrest in ARPE-19 cells, and that the arrest was significantly reduced in p53-silenced cells. Thus, p53 plays a central role in the response of ARPE-19 cells to DNA damaging agents that act via different mechanisms. Additionally, ARPE-19 cells with reduced p53 expression behave similar to tumor cell lines with mutated or non-functional p53. The present data demonstrate the utility of lentiviral vectors to create stable isogenic cell lines with reduced expression of a specific gene, thereby permitting the study of the function of a gene, the pathways controlled by it, and the effect of therapeutics on a cell with altered genetic makeup in a pair-wise fashion.

Efficient intracellular processing of the endogenous cystic fibrosis transmembrane conductance regulator in epithelial cell lines

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-dependent protein kinase A-activated chloride channel that resides on the apical surface of epithelial cells. One unusual feature of this protein is that during biogenesis, approximately 75% of wild type CFTR is degraded by the endoplasmic reticulum (ER)-associated degradative (ERAD) pathway. Examining the biogenesis and structural instability of the molecule has been technically challenging due to the limited amount of CFTR expressed in epithelia. Consequently, investigators have employed heterologous overexpression systems. Based on recent results that epithelial specific factors regulate both CFTR biogenesis and function, we hypothesized that CFTR biogenesis in endogenous CFTR expressing epithelial cells may be more efficient. To test this, we compared CFTR biogenesis in two epithelial cell lines endogenously expressing CFTR (Calu-3 and T84) with two heterologous expression systems (COS-7 and HeLa). Consistent with previous reports, 20 and 35% of the newly synthesized CFTR were converted to maturely glycosylated CFTR in COS-7 and HeLa cells, respectively. In contrast, CFTR maturation was virtually 100% efficient in Calu-3 and T84 cells. Furthermore, inhibition of the proteasome had no effect on CFTR biogenesis in Calu-3 cells, whereas it stabilized the immature form of CFTR in HeLa cells. Quantitative reverse transcriptase-PCR indicated that CFTR message levels are approximately 4-fold lower in Calu-3 than HeLa cells, yet steady-state protein levels are comparable. Our results question the structural instability model of wild type CFTR and indicate that epithelial cells endogenously expressing CFTR efficiently process this protein to post-Golgi compartments.

Novel Approaches to Models of Alzheimer's Disease Pathology for Drug Screening and Development

Development of therapeutics for Alzheimer's disease (AD) requires appropriate cell culture models that reflect the errant biochemical pathways and animal models that reflect the pathological hallmarks of the disease as well as the clinical manifestations. In the past two decades AD research has benefited significantly from the use of genetically engineered cell lines expressing components of the amyloid-generating pathway, as well as from the study of transgenic mice that develop the pathological hallmarks of the disease, mainly neuritic plaques. The choice of certain cell types and the choice of mouse as the model organism have been mandated by the feasibility of introduction and expression of foreign genes into these model systems. We describe a universal and efficient gene-delivery system, using lentiviral vectors, that permits the development of relevant cell biological systems using neuronal cells, including primary neurons and animal models in mammalian species best suited for the study of AD. In addition, lentiviral gene delivery provides avenues for creation of novel models by direct and prolonged expression of genes in the brain in any vertebrate animal. TranzVector is a lentiviral vector optimized for efficiency and safety that delivers genes to cells in culture, in tissue explants, and in live animals regardless of the dividing or differentiated status of the cells. Genes can also be delivered efficiently to fertilized single-cell-stage embryos of a wide range of mammalian species, broadening the range of the model organism (from rats to nonhuman primates) for the study of disease mechanism as well as for development of therapeutics.

Direct evidence that IFN-beta functions as a tumor-suppressor protein

Interferon-beta (IFN-beta) induces aberrant cell cycle progression as well as cytotoxicity and apoptosis. However, the relationship between the cell cycle alteration and the induction of cytotoxicity/apoptosis is unknown. Here, we report the first demonstration that the IFN-beta-induced direct cytotoxic/apoptotic effect can be separated functionally from its cell cycle effect. By using lentiviral transduction, we generated human tumor cells that stably expressed IFN-beta and were resistant to its direct cytotoxic/apoptotic effect. Despite this resistance to apoptosis, these cells showed significant S phase accumulation as measured by both FACS analyses and bromodeoxyuridine (BrdU) incorporation. Although the cells proliferated in the presence of high levels of IFN-beta, they had lost their tumorigenicity in mice. A portion of these cells was observed to undergo a tumor cell-specific senescence. Therefore, our study revealed a direct tumor-suppressor function of IFN-beta. This tumor-suppressor function was independent of IFN-beta-induced direct cytotoxic effect. It was also distinct from the IFN-beta-induced immunologic antitumor response, an indirect effect of IFN-beta. We conclude that the antiproliferative effect on human tumor cells is the collective activities of the direct cytotoxic/apoptotic effect, the cell cycle alteration that occurs as predominantly S phase accumulation, and less frequently other cell cycle effects, such as G(1) arrest, and the promotion of tumor cells into a senescent-like state.

Cancer risks in populations living near landfill sites in Great Britain

Previous studies have raised concerns about possible excess risks of bladder, brain and hepatobiliary cancers and leukaemias near landfill sites. Several cancers have been implicated, but no consistent pattern has emerged. We present a large nationwide analysis of selected cancers near landfill sites in Great Britain. The base population comprised people living within 2 km of 9565 (from a total of 19 196) landfill sites that were operational at some time from 1982 to 1997, with populations living more than 2 km from a landfill as reference. Risks of cancers at the above sites were computed with adjustment for age, sex, year of diagnosis, region and deprivation. National post-coded registers provided a total of 341 856 640 person-years for the adult cancer analyses and 113 631 443 person-years for childhood leukaemia. There were 89 786 cases of bladder cancer, 36 802 cases of brain cancer, 21 773 cases of hepatobiliary cancer, 37 812 cases of adult leukaemia and 3973 cases of childhood leukaemia. In spite of the very large scale of this national study, we found no excess risks of cancers of the bladder and brain, hepatobiliary cancer or leukaemia, in populations living within 2 km of landfill sites. The results were similar if the analysis were restricted to landfill sites licensed to carry special (hazardous) waste. Our results do not support suggestions of excess risks of cancer associated with landfill sites reported in other studies.

Aspiration cytodiagnosis of amyloid from vitreous fluid

Amyloidosis of the vitreous body is a rare disorder that causes progressive visual loss. In this report, a 36-yr-old female with familial amyloidosis is described in whom a progressive reduction of vision in both eyes over the last 4 yr was ascribed to vitreous opacities due to amyloid. A left pars plana vitrectomy was performed and an aspirated sample of the vitreous on cytologic examination showed vitreous strands admixed with abundant dense, pink, globular material which was intensely positive on Congo red staining and exhibited yellowish-green birefringence indicative of amyloid. This was further confirmed ultrastructurally, which showed the classical appearance of amyloid fibrils. The case is of interest not only in view of the rarity of the condition but also in view of the fact that as far as we are aware the cytodiagnosis of amyloid from an aspirate sample from the vitreous has not been previously described in the literature.

Temperature, housing, deprivation and their relationship to excess winter mortality in Great Britain, 1986-1996

OBJECTIVES

To examine the associations between temperature, housing, deprivation and excess winter mortality using census variables as proxies for housing conditions.

DESIGN

Small area ecological study at electoral ward level. Setting Great Britain between 1986 and 1996.

PARTICIPANTS

Men and women aged 65 and over.

MAIN OUTCOME MEASURES

Deaths from all causes (International Classification of Diseases, Ninth Revision [ICD-9] codes 0-999), coronary heart disease (ICD-9 410-414), stroke (ICD-9 430-438) and respiratory diseases (ICD-9 460-519). Odds of death occurring in winter period of the four months December to March compared to the rest of the year.

RESULTS

During the study period (excluding the influenza epidemic year of 1989/90), a total of 1,682,687 deaths occurred in winter and 2,825,223 deaths occurred during the rest of the year among people aged > or =65 (around 30,000 excess winter deaths per year). A trend of higher excess winter mortality with age was apparent across all disease categories (P < 0.01). There was a significant association between winter mortality and temperature with a 1.5% higher odds of dying in winter for every 1 degrees C reduction in 24-h mean winter temperature. The amount of rain, wind and hours of sunshine were inversely associated with excess winter mortality. Selected housing variables derived from the English House Condition Survey showed little agreement with census-derived variables at electoral ward level. For all-cause mortality there was little association between deprivation and excess winter mortality, although lack of central heating was associated with a higher risk of dying in winter (odds ratio [OR] = 1.016, 95% CI : 1.009-1.022).

CONCLUSIONS

Excess winter mortality continues to be an important public health problem in Great Britain. There was a strong inverse association with temperature. Lack of central heating was associated with higher excess winter mortality. Further work is needed to disentangle the complex relationships between different indicators of housing quality and other measures of socioeconomic deprivation and their relationship to the high number of excess winter deaths in Great Britain.

Errors-in-variables in joint population pharmacokinetic/pharmacodynamic modeling

Pharmacokinetic (PK) models describe the relationship between the administered dose and the concentration of drug (and/or metabolite) in the blood as a function of time. Pharmacodynamic (PD) models describe the relationship between the concentration in the blood (or the dose) and the biologic response. Population PK/PD studies aim to determine the sources of variability in the observed concentrations/responses across groups of individuals. In this article, we consider the joint modeling of PK/PD data. The natural approach is to specify a joint model in which the concentration and response data are simultaneously modeled. Unfortunately, this approach may not be optimal if, due to sparsity of concentration data, an overly simple PK model is specified. As an alternative, we propose an errors-in-variables approach in which the observed-concentration data are assumed to be measured with error without reference to a specific PK model. We give an example of an analysis of PK/PD data obtained following administration of an anticoagulant drug. The study was originally carried out in order to make dosage recommendations. The prior for the distribution of the true concentrations, which may incorporate an individual's covariate information, is derived as a predictive distribution from an earlier study. The errors-in-variables approach is compared with the joint modeling approach and more naive methods in which the observed concentrations, or the separately modeled concentrations, are substituted into the response model. Throughout, a Bayesian approach is taken with implementation via Markov chain Monte Carlo methods.

Risk of adverse birth outcomes in populations living near landfill sites

OBJECTIVE

To investigate the risk of adverse birth outcomes associated with residence near landfill sites in Great Britain.

DESIGN

Geographical study of risks of adverse birth outcomes in populations living within 2 km of 9565 landfill sites operational at some time between 1982 and 1997 (from a total of 19 196 sites) compared with those living further away.

SETTING

Great Britain.

SUBJECTS

Over 8.2 million live births, 43 471 stillbirths, and 124 597 congenital anomalies (including terminations).

MAIN OUTCOME MEASURES

All congenital anomalies combined, some specific anomalies, and prevalence of low and very low birth weight (<2500 g and <1500 g).

RESULTS

For all anomalies combined, relative risk of residence near landfill sites (all waste types) was 0.92 (99% confidence interval 0.907 to 0.923) unadjusted, and 1.01 (1.005 to 1.023) adjusted for confounders. Adjusted risks were 1.05 (1.01 to 1.10) for neural tube defects, 0.96 (0.93 to 0.99) for cardiovascular defects, 1.07 (1.04 to 1.10) for hypospadias and epispadias (with no excess of surgical correction), 1.08 (1.01 to 1.15) for abdominal wall defects, 1.19 (1.05 to 1.34) for surgical correction of gastroschisis and exomphalos, and 1.05 (1.047 to 1.055) and 1.04 (1.03 to 1.05) for low and very low birth weight respectively. There was no excess risk of stillbirth. Findings for special (hazardous) waste sites did not differ systematically from those for non-special sites. For some specific anomalies, higher risks were found in the period before opening compared with after opening of a landfill site, especially hospital admissions for abdominal wall defects.

CONCLUSIONS

We found small excess risks of congenital anomalies and low and very low birth weight in populations living near landfill sites. No causal mechanisms are available to explain these findings, and alternative explanations include data artefacts and residual confounding. Further studies are needed to help differentiate between the various possibilities.

Cumulative logit models for ordinal data: a case study involving allergic rhinitis severity scores

Ordered categorical data arise in numerous settings, a common example being pain scores in analgesic trials. The modelling of such data is intrinsically more difficult than the modelling of continuous data due to the constraints on the underlying probabilities and the reduced amount of information that discrete outcomes contain. In this paper we discuss the class of cumulative logit models, which provide a natural framework for ordinal data analysis. We show how viewing the categorical outcome as the discretization of an underlying continuous response allows a natural interpretation of model parameters. We also show how covariates are incorporated into the model and how various types of correlation among repeated measures on the same individual may be accounted for. The models are illustrated using longitudinal allergy data consisting of sneezing scores measured on a four-point scale. Our approach throughout is Bayesian and we present a range of simple diagnostics to aid model building.

Spatial variation and temporal trends of testicular cancer in Great Britain

Increases in testicular cancer incidence have been reported in several countries over a long period. Geographical variability has also been reported in some studies. We have investigated temporal trends and spatial variation of testicular cancer at ages 20-49 in Britain. Temporal trends in testicular cancer incidence were examined, 1974 to 1991 and in mortality, 1981-1997. Spatial variation in incidence was analysed across electoral wards, 1975 to 1991. We used Poisson regression to examine for regional and socio-economic effects and Bayesian mapping techniques to analyse small-area spatial variability. Incidence increased from 6.5 to 11.1 per 100 000 in men at ages 20-34, and from 5.6 to 9.7 per 100 000 in men at ages 35-49, while mortality declined by 50% in both age groups. Risks of testicular cancer varied across regional cancer registries, ranging from 0.79 (95% CI: 0.73-0.84) to 1.32 (95% CI: 1.25-1.38), and was higher in the most affluent compared with the most deprived areas. Analyses within 2 regions (one predominantly urban, the other predominantly rural) did not indicate any localized geographical clustering. The increasing incidence contrasted with a decreasing mortality over time in Great Britain, similar to that found in other countries. The higher risk in more affluent areas is not consistent with findings on social class at the individual level. The absence of any marked geographical variability at small area scale argues against a geographically varying environmental factor operating strongly in the aetiology of testicular cancer.

Environmental Florence Nightingales: nursing's new front line

Nurses comprise the largest health professional group in terms of number, and they can be found in almost every health care setting, including homes, schools, work sites, and hospitals. To a large extent, nurses have always been aware of environmental factors when doing their job, but the definition of environmental health nursing is being expanded. Today, in addition to considering the possibility of environmental influences when taking patient health histories, evaluating symptoms, and conducting community assessments, nurses may change environmental conditions of affected individuals or populations through direct care, teaching, advocacy, and public policy initiatives. Nurses are helping patients evaluate the relative risks of various types of environmental exposures, such as lead. And they are also playing a key role in establishing a national tracking system of environmental health as well as in conducting patient research.

Proximity to coke works and hospital admissions for respiratory and cardiovascular disease in England and Wales

BACKGROUND

The incidence of hospital admissions for respiratory and cardiovascular diseases in areas close to operating coke works in England and Wales was investigated.

METHODS

A small area study using distance from source as a proxy for exposure was undertaken in subjects aged 65 or over and children under 5 years within 7.5 km of four coke works (1991 estimated populations 87 760 and 43 932, respectively). The main outcome measures were emergency hospital admissions in 1992/3-1994/5 with a primary diagnosis of coronary heart disease (ICD 410-414), stroke (ICD 431-438), all respiratory diseases (ICD 460-519), chronic obstructive pulmonary disease (ICD 491-492), and asthma (ICD 493) in those aged 65 or over, and all respiratory and asthma admissions in children under 5 years of age.

RESULTS

At age 65 or over the combined estimate of relative risk with proximity to coke works (per km) ranged from 0.99 (95% CI 0.90 to 1.09) for chronic obstructive pulmonary disease to 1.03 (95% CI 0.94 to 1.13) for asthma. For children under 5 years the combined estimate of risk was 1.08 (95% CI 0.98 to 1.20) for all respiratory disease and 1.07 (95% CI 0.98 to 1.18) for asthma. There was evidence of significant heterogeneity in risk estimates between coke work groups, especially in children under 5 years (p<0.001 and p=0.004 for respiratory disease and asthma, respectively). For the Teesside coke works in North East England the relative risk with proximity (per km) was 1.09 (95% CI 1.06 to 1.12) for respiratory disease and 1.09 (95% CI 1.04 to 1.15) for asthma.

CONCLUSIONS

No evidence overall was found for an association between hospital admissions and living near operational coke works in England and Wales. Trends of a higher risk of hospital admission for respiratory disease and asthma among children with proximity to the Teesside plant require further investigation.