Rapid, high throughput, automated detection of SARS-CoV-2 neutralizing antibodies against Wuhan-WT, delta and omicron BA1, BA2 spike trimers

Traditional cellular and live-virus methods for detection of SARS-CoV-2 neutralizing antibodies (nAbs) are labor- and time-intensive, and thus not suited for routine use in the clinical lab to predict vaccine efficacy and natural immune protection. Here, we report the development and validation of a rapid, high throughput method for measuring SARS-CoV-2 nAbs against native-like trimeric spike proteins. This assay uses a blockade of human angiotensin converting enzyme 2 (hACE-2) binding (BoAb) approach in an automated digital immunoassay on the Quanterix HD-X platform. BoAb assays using Wuhan-WT (vaccine strain), delta (B.1.167.2), omicron BA1 and BA2 variant viral strains showed strong correlation with cell-based pseudovirus neutralization activity (PNA) and live-virus neutralization activity. Importantly, we were able to detect similar patterns of delta and omicron variant resistance to neutralization in samples with paired vaccine strain and delta variant BoAb measurements. Finally, we screened clinical samples from patients with or without evidence of SARS-CoV-2 exposure by a single-dilution screening version of our assays, finding significant nAb activity only in exposed individuals. Importantly, this completely automated assay can be performed in 4 h to measure neutralizing antibody titers for 16 samples over 8 serial dilutions or, 128 samples at a single dilution with replicates. In principle, these assays offer a rapid, robust, and scalable alternative to time-, skill-, and cost-intensive standard methods for measuring SARS-CoV-2 nAb levels.

DKK1 drives immune suppressive phenotypes in intrahepatic cholangiocarcinoma and can be targeted with anti-DKK1 therapeutic DKN-01

BACKGROUND AND AIMS

Dickkopf-1 (DKK1) is associated with poor prognosis in intrahepatic cholangiocarcinoma (iCCA), but the mechanisms behind this are unclear. Here, we show that DKK1 plays an immune regulatory role in vivo and inhibition reduces tumour growth.

METHODS

Various in vivo GEMM mouse models and patient samples were utilized to assess the effects of tumour specific DKK1 overexpression in iCCA. DKK1-driven changes to the tumour immune microenvironment were characterized by immunostaining and gene expression analysis. DKK1 overexpressing and damage-induced models of iCCA were used to demonstrate the therapeutic efficacy of DKK1 inhibition in these contexts using the anti-DKK1 therapeutic, DKN-01.

RESULTS

DKK1 overexpression in mouse models of iCCA drives an increase in chemokine and cytokine signalling, the recruitment of regulatory macrophages, and promotes the formation of a tolerogenic niche with higher numbers of regulatory T cells. We show a similar association of DKK1 with FOXP3 and regulatory T cells in patient tissue and gene expression data, demonstrating these effects are relevant to human iCCA. Finally, we demonstrate that inhibition of DKK1 with the monoclonal antibody mDKN-01 is effective at reducing tumour burden in two distinct mouse models of the disease.

CONCLUSION

DKK1 promotes tumour immune evasion in iCCA through the recruitment of immune suppressive macrophages. Targeting DKK1 with a neutralizing antibody is effective at reducing tumour growth in vivo. As such, DKK1 targeted and immune modulatory therapies may be an effective strategy in iCCA patients with high DKK1 tumour expression or tolerogenic immune phenotypes.

In Vivo Modeling of Patient Genetic Heterogeneity Identifies New Ways to Target Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy of the bile ducts within the liver characterized by high levels of genetic heterogeneity. In the context of such genetic variability, determining which oncogenic mutations drive ICC growth has been difficult, and developing modes of patient stratification and targeted therapies remains challenging. Here we model the interactions between rare mutations with more common driver genes and combine in silico analysis of patient data with highly multiplexed in vivo CRISPR-spCas9 screens to perform a functional in vivo study into the role genetic heterogeneity plays in driving ICC. Novel tumor suppressors were uncovered, which, when lost, cooperate with the RAS oncoprotein to drive ICC growth. Focusing on a set of driver mutations that interact with KRAS to initiate aggressive, sarcomatoid-type ICC revealed that tumor growth relies on Wnt and PI3K signaling. Pharmacologic coinhibition of Wnt and PI3K in vivo impeded ICC growth regardless of mutational profile. Therefore, Wnt and PI3K activity should be considered as a signature by which patients can be stratified for treatment independent of tumor genotype, and inhibitors of these pathways should be levied to treat ICC.

SIGNIFICANCE

This work shows that, despite significant genetic heterogeneity, intrahepatic cholangiocarcinoma relies on a limited number of signaling pathways to grow, suggesting common therapeutic vulnerabilities across patients.

Rapid, high throughput, automated detection of SARS-CoV-2 neutralizing antibodies against native-like vaccine and delta variant spike trimers

Traditional cellular and live-virus methods for detection of SARS-CoV-2 neutralizing antibodies (nAbs) are labor- and time-intensive, and thus not suited for routine use in the clinical lab to predict vaccine efficacy and natural immune protection. Here, we report the development and validation of a rapid, high throughput method for measuring SARS-CoV-2 nAbs against native-like trimeric spike proteins. This assay uses a blockade of hACE-2 binding (BoAb) approach in an automated digital immunoassay on the Quanterix HD-X platform. BoAb assays using vaccine and delta variant viral strains showed strong correlation with cell-based pseudovirus and live-virus neutralization activity. Importantly, we were able to detect similar patterns of delta variant resistance to neutralization in samples with paired vaccine and delta variant BoAb measurements. Finally, we screened clinical samples from patients with or without evidence of SARS-CoV-2 exposure by a single-dilution screening version of our assays, finding significant nAb activity only in exposed individuals. In principle, these assays offer a rapid, robust, and scalable alternative to time-, skill-, and cost-intensive standard methods for measuring SARS-CoV-2 nAb levels.

Rapid, high throughput, automated detection of SARS-CoV-2 neutralizing antibodies against native-like vaccine and delta variant spike trimers

Traditional cellular and live-virus methods for detection of SARS-CoV-2 neutralizing antibodies (nAbs) are labor- and time-intensive, and thus not suited for routine use in the clinical lab to predict vaccine efficacy and natural immune protection. Here, we report the development and validation of a rapid, high throughput method for measuring SARS-CoV-2 nAbs against native-like trimeric spike proteins. This assay uses a blockade of hACE-2 binding (BoAb) approach in an automated digital immunoassay on the Quanterix HD-X platform. BoAb assays using vaccine and delta variant viral strains showed strong correlation with cell-based pseudovirus and live-virus neutralization activity. Importantly, we were able to detect similar patterns of delta variant resistance to neutralization in samples with paired vaccine and delta variant BoAb measurements. Finally, we screened clinical samples from patients with or without evidence of SARS-CoV-2 exposure by a single-dilution screening version of our assays, finding significant nAb activity only in exposed individuals. In principle, these assays offer a rapid, robust, and scalable alternative to time-, skill-, and cost-intensive standard methods for measuring SARS-CoV-2 nAb levels.

N-protein presents early in blood, dried blood and saliva during asymptomatic and symptomatic SARS-CoV-2 infection

The COVID-19 pandemic continues to have an unprecedented impact on societies and economies worldwide. There remains an ongoing need for high-performance SARS-CoV-2 tests which may be broadly deployed for infection monitoring. Here we report a highly sensitive single molecule array (Simoa) immunoassay in development for detection of SARS-CoV-2 nucleocapsid protein (N-protein) in venous and capillary blood and saliva. In all matrices in the studies conducted to date we observe >98% negative percent agreement and >90% positive percent agreement with molecular testing for days 1-7 in symptomatic, asymptomatic, and pre-symptomatic PCR+ individuals. N-protein load decreases as anti-SARS-CoV-2 spike-IgG increases, and N-protein levels correlate with RT-PCR Ct-values in saliva, and between matched saliva and capillary blood samples. This Simoa SARS-CoV-2 N-protein assay effectively detects SARS-CoV-2 infection via measurement of antigen levels in blood or saliva, using non-invasive, swab-independent collection methods, offering potential for at home and point of care sample collection.

Admission Levels of Total Tau and β-Amyloid Isoforms 1-40 and 1-42 in Predicting the Outcome of Mild Traumatic Brain Injury

Background: The purpose of this study was to investigate if admission levels of total tau (T-tau) and β-amyloid isoforms 1-40 (Aβ40) and 1-42 (Aβ42) could predict clinical outcome in patients with mild traumatic brain injury (mTBI).

Methods: A total of 105 patients with mTBI [Glasgow Coma Scale (GCS) ≥ 13] recruited in Turku University Hospital, Turku, Finland were included in this study. Blood samples were drawn within 24 h of admission for analysis of plasma T-tau, Aβ40, and Aβ42. Patients were divided into computed tomography (CT)-positive and CT-negative groups. The outcome was assessed 6–12 months after the injury using the Extended Glasgow Outcome Scale (GOSE). Outcomes were defined as complete (GOSE 8) or incomplete (GOSE < 8) recovery. The Rivermead Post Concussion Symptoms Questionnaire (RPCSQ) was also used to assess mTBI-related symptoms. Predictive values of the biomarkers were analyzed independently, in panels and together with clinical parameters.

Results: The admission levels of plasma T-tau, Aβ40, and Aβ42 were not significantly different between patients with complete and incomplete recovery. The levels of T-tau, Aβ40, and Aβ42 could poorly predict complete recovery, with areas under the receiver operating characteristic curve 0.56, 0.52, and 0.54, respectively. For the whole cohort, there was a significant negative correlation between the levels of T-tau and ordinal GOSE score (Spearman ρ = −0.231, p = 0.018). In a multivariate logistic regression model including age, GCS, duration of posttraumatic amnesia, Injury Severity Score (ISS), time from injury to sampling, and CT findings, none of the biomarkers could predict complete recovery independently or together with the other two biomarkers. Plasma levels of T-tau, Aβ40, and Aβ42 did not significantly differ between the outcome groups either within the CT-positive or CT-negative subgroups. Levels of Aβ40 and Aβ42 did not significantly correlate with outcome, but in the CT-positive subgroup, the levels of T-tau significantly correlated with ordinal GOSE score (Spearman ρ = −0.288, p = 0.035). The levels of T-tau, Aβ40, and Aβ42 were not correlated with the RPCSQ scores.

Conclusions: The early levels of T-tau are correlated with the outcome in patients with mTBI, but none of the biomarkers either alone or in any combinations could predict complete recovery in patients with mTBI.

Non-canonical Wnt signalling regulates scarring in biliary disease via the planar cell polarity receptors

The number of patients diagnosed with chronic bile duct disease is increasing and in most cases these diseases result in chronic ductular scarring, necessitating liver transplantation. The formation of ductular scaring affects liver function; however, scar-generating portal fibroblasts also provide important instructive signals to promote the proliferation and differentiation of biliary epithelial cells. Therefore, understanding whether we can reduce scar formation while maintaining a pro-regenerative microenvironment will be essential in developing treatments for biliary disease. Here, we describe how regenerating biliary epithelial cells express Wnt-Planar Cell Polarity signalling components following bile duct injury and promote the formation of ductular scars by upregulating pro-fibrogenic cytokines and positively regulating collagen-deposition. Inhibiting the production of Wnt-ligands reduces the amount of scar formed around the bile duct, without reducing the development of the pro-regenerative microenvironment required for ductular regeneration, demonstrating that scarring and regeneration can be uncoupled in adult biliary disease and regeneration.

Embryonic mesothelial-derived hepatic lineage of quiescent and heterogenous scar-orchestrating cells defined but suppressed by WT1

Activated hepatic stellate cells (aHSCs) orchestrate scarring during liver injury, with putative quiescent precursor mesodermal derivation. Here we use lineage-tracing from development, through adult homoeostasis, to fibrosis, to define morphologically and transcriptionally discreet subpopulations of aHSCs by expression of WT1, a transcription factor controlling morphological transitions in organogenesis and adult homoeostasis. Two distinct populations of aHSCs express WT1 after injury, and both re-engage a transcriptional signature reflecting embryonic mesothelial origin of their discreet quiescent adult precursor. WT1-deletion enhances fibrogenesis after injury, through upregulated Wnt-signalling and modulation of genes central to matrix persistence in aHSCs, and augmentation of myofibroblastic transition. The mesothelial-derived lineage demonstrates punctuated phenotypic plasticity through bidirectional mesothelial-mesenchymal transitions. Our findings demonstrate functional heterogeneity of adult scar-orchestrating cells that can be whole-life traced back through specific quiescent adult precursors to differential origin in development, and define WT1 as a paradoxical regulator of aHSCs induced by injury but suppressing scarring.

Correlation of Blood Biomarkers and Biomarker Panels with Traumatic Findings on Computed Tomography after Traumatic Brain Injury

The aim of the study was to examine the ability of eight protein biomarkers and their combinations in discriminating computed tomography (CT)-negative and CT-positive patients with traumatic brain injury (TBI), utilizing highly sensitive immunoassays in a well-characterized cohort. Blood samples were obtained from 160 patients with acute TBI within 24 h of admission. Levels of β-amyloid isoforms 1-40 (Aβ40) and 1-42 (Aβ42), glial fibrillary acidic protein (GFAP), heart fatty-acid binding protein (H-FABP), interleukin 10 (IL-10), neurofilament light (NF-L), S100 calcium-binding protein B (S100B), and tau were measured. Patients were divided into CT-negative (n = 65) and CT-positive (n = 95), and analyses were conducted separately for TBIs of all severities (Glasgow Coma Scale [GCS] score 3-15) and mild TBIs (mTBIs; GCS 13-15). NF-L, GFAP, and tau were the best in discriminating CT-negative and CT-positive patients, both in patients with mTBI and with all severities. In patients with all severities, area under the curve of the receiver operating characteristic (AUC) was 0.822, 0.817, and 0.781 for GFAP, NF-L, and tau, respectively. In patients with mTBI, AUC was 0.720, 0.689, and 0.676, for GFAP, tau, and NF-L, respectively. The best panel of three biomarkers for discriminating CT-negative and CT-positive patients in the group of all severities was a combination of GFAP+H-FABP+IL-10, with a sensitivity of 100% and specificity of 38.5%. In patients with mTBI, the best panel of three biomarkers was H-FABP+S100B+tau, with a sensitivity of 100% and specificity of 46.4%. Panels of biomarkers outperform individual biomarkers in separating CT-negative and CT-positive patients. Panels consisted mainly of different biomarkers than those that performed best as an individual biomarker.

Early Levels of Glial Fibrillary Acidic Protein and Neurofilament Light Protein in Predicting the Outcome of Mild Traumatic Brain Injury

The purpose of this study was to correlate the early levels of glial fibrillary acidic protein (GFAP) and neurofilament light protein (NF-L) with outcome in patients with mild traumatic brain injury (mTBI). A total of 107 patients with mTBI (Glasgow Coma Scale ≥13) who had blood samples for GFAP and NF-L available within 24 h of arrival were included. Patients with mTBI were divided into computed tomography (CT)-positive and CT-negative groups. Glasgow Outcome Scale-Extended (GOSE) was used to assess the outcome. Outcomes were defined as complete (GOSE 8) versus incomplete (GOSE <8), and favorable (GOSE 5-8) versus unfavorable (GOSE 1-4). GFAP and NF-L concentrations in blood were measured using ultrasensitive single molecule array technology. Patients with incomplete recovery had significantly higher levels of NF-L compared with those with complete recovery (p = 0.005). The levels of GFAP and NF-L were significantly higher in patients with unfavorable outcome than in patients with favorable outcome (p = 0.002 for GFAP and p < 0.001 for NF-L). For predicting favorable outcome, the area under the receiver operating characteristic curve for GFAP and NF-L was 0.755 and 0.826, respectively. In a multi-variate logistic regression model, the level of NF-L was still a significant predictor for complete recovery (odds ratio [OR] = 1.008; 95% confidence interval [CI], 1.000-1.016). Moreover, the level of NF-L was a significant predictor for complete recovery in CT-positive patients (OR = 1.009; 95% CI, 1.001-1.016). The early levels of GFAP and NF-L are significantly correlated with the outcome in patients with mTBI. The level of NF-L within 24 h from arrival has a significant predictive value in mTBI also in a multi-variate model.

Performance Evaluation of a Multiplex Assay for Simultaneous Detection of Four Clinically Relevant Traumatic Brain Injury Biomarkers

Traumatic brain injury (TBI) results in heterogeneous pathology affecting multiple cells and tissue types in the brain. It is likely that assessment of such complexity will require simultaneous measurement of multiple molecular biomarkers in a single sample of biological fluid. We measured glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase L1 (UCH-L1), neurofilament light chain (NF-L) and total tau in plasma samples obtained from 107 subjects enrolled in the Transforming Research and Clinical Knowledge in Traumatic Brain Injury Pilot (TRACK-TBI Pilot) Study using the Quanterix Simoa 4-Plex assay. We also measured NF-L using the Simoa singleplex assay. We computed the correlation between the different biomarkers and calculated the discriminative value of each biomarker for distinguishing between subjects with abnormal versus normal head computed tomography (CT). We found a strong correlation between NF-L values derived from the multiplex and singleplex assays (correlation coefficient = 0.997). Among biomarker values derived from the multiplex assay, the strongest correlation was between the axonal and neuronal markers, NF-L and UCH-L1 (coefficient = 0.71). The weakest correlation was between the glial marker GFAP and the axonal marker tau (coefficient = 0.06). The areas under the curves for distinguishing between subjects with/without abnormal head CT for multiplex GFAP, UCH-L1, NF-L, and total tau were: 0.88 (95% confidence interval 0.81-0.95), 0.86 (0.79-0.93), 0.84 (0.77-0.92), and 0.77 0.67-0.86), respectively. We conclude that the multiplex assay provides simultaneous quantification of GFAP, UCH-L1, NF-L, and tau, and may be clinically useful in the diagnosis of TBI as well as identifying different types of cellular injury.

Blood biomarkers indicate mild neuroaxonal injury and increased amyloid β production after transient hypoxia during breath-hold diving

OBJECTIVE

To determine whether transient hypoxia during breath-hold diving causes neuronal damage or dysfunction or alters amyloid metabolism as measured by certain blood biomarkers.

DESIGN

Sixteen divers competing in the national Swedish championship in breath-hold diving and five age-matched healthy control subjects were included. Blood samples were collected at baseline and over a course of 3 days where the divers competed in static apnea (STA), dynamic apnea without fins (DYN1) and dynamic apnea with fins (DYN2).

MAIN OUTCOMES

Biomarkers reflecting brain injury and amyloid metabolism were analysed in serum (S-100β, NFL) and plasma (T-tau, Aβ42) using immunochemical methods.

RESULTS

Compared to divers' baseline, Aβ42 increased after the first event of static apnea (p = 0.0006). T-tau increased (p = 0.001) in STA vs baseline and decreased after one of the dynamic events, DYN2 (p = 0.03). Further, T-tau correlated with the length of the apneic time during STA (ρ = 0.7226, p = 0.004) and during DYN1 (ρ = 0.66, p = 0.01).

CONCLUSION

The findings suggest that transient hypoxia may acutely increase the levels of Aβ42 and T-tau in plasma of healthy adults, further supporting that general hypoxia may cause mild neuronal dysfunction or damage and stimulate Aβ production.

Loss of fibronectin from the aged stem cell niche affects the regenerative capacity of skeletal muscle in mice

Age-related changes in the niche have long been postulated to impair the function of somatic stem cells. Here we demonstrate that the aged stem cell niche in skeletal muscle contains substantially reduced levels of fibronectin (FN), leading to detrimental consequences for the function and maintenance of muscle stem cells (MuSCs). Deletion of the gene encoding FN from young regenerating muscles replicates the aging phenotype and leads to a loss of MuSC numbers. By using an extracellular matrix (ECM) library screen and pathway profiling, we characterize FN as a preferred adhesion substrate for MuSCs and demonstrate that integrin-mediated signaling through focal adhesion kinase and the p38 mitogen-activated protein kinase pathway is strongly de-regulated in MuSCs from aged mice because of insufficient attachment to the niche. Reconstitution of FN levels in the aged niche remobilizes stem cells and restores youth-like muscle regeneration. Taken together, we identify the loss of stem cell adhesion to FN in the niche ECM as a previously unknown aging mechanism.

Rapid, Fully Automated Digital Immunoassay for p24 Protein with the Sensitivity of Nucleic Acid Amplification for Detecting Acute HIV Infection

BACKGROUND

Nucleic acid testing (NAT) has become the standard for high sensitivity in detecting low levels of virus. However, adoption of NAT can be cost prohibitive in low-resource settings where access to extreme sensitivity could be clinically advantageous for early detection of infection. We report development and preliminary validation of a simple, low-cost, fully automated digital p24 antigen immunoassay with the sensitivity of quantitative NAT viral load (NAT-VL) methods for detection of acute HIV infection.

METHODS

We developed an investigational 69-min immunoassay for p24 capsid protein for use on a novel digital analyzer on the basis of single-molecule-array technology. We evaluated the assay for sensitivity by dilution of standardized preparations of p24, cultured HIV, and preseroconversion samples. We characterized analytical performance and concordance with 2 NAT-VL methods and 2 contemporary p24 Ag/Ab combination immunoassays with dilutions of viral isolates and samples from the earliest stages of HIV infection.

RESULTS

Analytical sensitivity was 0.0025 ng/L p24, equivalent to 60 HIV RNA copies/mL. The limit of quantification was 0.0076 ng/L, and imprecision across 10 runs was <10% for samples as low as 0.09 ng/L. Clinical specificity was 95.1%. Sensitivity concordance vs NAT-VL on dilutions of preseroconversion samples and Group M viral isolates was 100%.

CONCLUSIONS

The digital immunoassay exhibited >4000-fold greater sensitivity than contemporary immunoassays for p24 and sensitivity equivalent to that of NAT methods for early detection of HIV. The data indicate that NAT-level sensitivity for acute HIV infection is possible with a simple, low-cost digital immunoassay.

Fully automated ultrasensitive digital immunoassay for cardiac troponin I based on single molecule array technology

BACKGROUND

The association between increases in cardiac troponin and adverse cardiac outcomes is well established. There is a growing interest in exploring routine cardiac troponin monitoring as a potential early indicator of adverse heart health trends. Prognostic use of cardiac troponin measurements requires an assay with very high sensitivity and outstanding analytical performance. We report development and preliminary validation of an investigational assay meeting these requirements and demonstrate its applicability to cohorts of healthy individuals and patients with heart failure.

METHODS

On the basis of single molecule array technology, we developed a 45-min immunoassay for cardiac troponin I (cTnI) for use on a novel, fully automated digital analyzer. We characterized its analytical performance and measured cTnI in healthy individuals and heart failure patients in a preliminary study of assay analytical efficacy.

RESULTS

The assay exhibited a limit of detection of 0.01 ng/L, a limit of quantification of 0.08 ng/L, and a total CV of 10% at 2.0 ng/L. cTnI concentrations were well above the assay limit of detection for all samples tested, including samples from healthy individuals. cTnI was significantly higher in heart failure patients, and exhibited increasing median and interquartile concentrations with increasing New York Heart Association classification of heart failure severity.

CONCLUSIONS

The robust 2-log increase in sensitivity relative to contemporary high-sensitivity cardiac troponin immunoassays, combined with full automation, make this assay suitable for exploring cTnI concentrations in cohorts of healthy individuals and for the potential prognostic application of serial cardiac troponin measurements in both apparently healthy and diseased individuals.

WNT signaling drives cholangiocarcinoma growth and can be pharmacologically inhibited

Cholangiocarcinoma (CC) is typically diagnosed at an advanced stage and is refractory to surgical intervention and chemotherapy. Despite a global increase in the incidence of CC, little progress has been made toward the development of treatments for this cancer. Here we utilized human tissue; CC cell xenografts; a p53-deficient transgenic mouse model; and a non-transgenic, chemically induced rat model of CC that accurately reflects both the inflammatory and regenerative background associated with human CC pathology. Using these systems, we determined that the WNT pathway is highly activated in CCs and that inflammatory macrophages are required to establish this WNT-high state in vivo. Moreover, depletion of macrophages or inhibition of WNT signaling with one of two small molecule WNT inhibitors in mouse and rat CC models markedly reduced CC proliferation and increased apoptosis, resulting in tumor regression. Together, these results demonstrate that enhanced WNT signaling is a characteristic of CC and suggest that targeting WNT signaling pathways has potential as a therapeutic strategy for CC.

Inhibition of JAK-STAT signaling stimulates adult satellite cell function

Diminished regenerative capacity of skeletal muscle occurs during adulthood. We identified a reduction in the intrinsic capacity of murine adult satellite cells to contribute to regeneration and repopulate the niche. Gene expression analysis identified an increase in expression of JAK/STAT signaling targets between 3 week old and 18 month old mice. Knockdown of Jak2 or Stat3 significantly stimulated symmetric satellite stem cell divisions on cultured myofibers. Knockdown of Jak2 or Stat3 in prospectively isolated satellite cells markedly enhanced their ability to repopulate the satellite cell niche. Pharmacological inhibition of Jak2 and Stat3 similarly stimulated symmetric expansion of satellite cells in vitro and their engraftment in vivo. Intramuscular injection of these drugs resulted in a dramatic enhancement of muscle repair and force generation. Together these results reveal intrinsic properties that functionally distinguish adult satellite cells and suggest a promising therapeutic avenue for the treatment of muscle wasting diseases.

Our perception of weight: Socioeconomic and sociocultural explanations

SUMMARY

OBJECTIVE

To compare self-reported perception of weight with biomedically measured body mass index in different socioeconomic and cultural groups.

METHOD

Of the original North West Adelaide Health (Cohort) Study (n = 4060) 68.5% (n = 2780) underwent a computer assisted telephone interview (CATI) answering additional questions related to their social and health status. The participants were asked "In terms of your weight, do you consider yourself to be… too thin, a little thin, normal weight, a little overweight or very overweight". The self-perception of weight was compared to biomedically measured BMI (body mass index). Binary logistic regression was used to compare those participants who were obese (BMI ≥ 30) with the self-perceived weight status of 'a little overweight'. The outcome measures included the Socioeconomic Indexes for Areas Index of Relative Socioeconomic Disadvantage (SEIFA IRSD), country of birth and household income.

RESULTS

Of those that were underestimating their obese weight status, 41.5% were male and 32.2% female. The highest misclassification was for those who considered their weight to be 'a little overweight', with 59.6% biomedically measured with a BMI of over 30. The odds of being biomedically measured obese (BMI ≥ 30) were compared to those who considered themselves to be 'a little overweight'. Those that misreported their weight status and were biomedically obese, were more likely to be living in the lowest quintile of disadvantage, have a household income of less then $20,000 or be born in Eastern or Western Europe.

CONCLUSION

There are psychosocial, sociocultural and social environmental influences related to the perception of weight status. Future research will need to understand the processes whereby people are not aware they have a weight problem.

Imatinib treatment and Aβ42 in humans

BACKGROUND

The first-line treatment in chronic myeloid leukemia (CML), imatinib, has been shown to decrease the production of amyloid-β (Aβ) in vitro and in animal studies. However, whether imatinib has this effect in humans is not known.

METHODS

Plasma levels of Aβ42 were analyzed in sequential samples from CML patients treated with imatinib (n=51). The effect of imatinib on Aβ production was also investigated in human embryonic kidney 293 (HEK293) cells overexpressing the amyloid precursor protein (APP) with the Swedish mutation, in mouse primary cortical neurons and in human Down syndrome embryonic stem-cell-derived cortical neurons.

RESULTS

Twelve months of imatinib treatment did not lower plasma Aβ42 levels in CML patients, and imatinib treatment did not lead to less Aβ42 production in any of the in vitro models whereas β- and γ-secretase inhibitors did.

CONCLUSION

These data question the previously described role of imatinib in inhibiting amyloidogenic APP processing and as a drug candidate for AD.

Cohort profile: The men androgen inflammation lifestyle environment and stress (MAILES) study

The Men Androgen Inflammation Lifestyle Environment and Stress (MAILES) Study was established in 2009 to investigate the associations of sex steroids, inflammation, environmental and psychosocial factors with cardio-metabolic disease risk in men. The study population consists of 2569 men from the harmonisation of two studies: all participants of the Florey Adelaide Male Ageing Study (FAMAS) and eligible male participants of the North West Adelaide Health Study (NWAHS). The cohort has so far participated in three stages of the MAILES Study: MAILES1 (FAMAS Wave 1, from 2002-2005, and NWAHS Wave 2, from 2004-2006); MAILES2 (FAMAS Wave 2, from 2007-2010, and NWAHS Wave 3, from 2008-2010); and MAILES3 (a computer-assisted telephone interview (CATI) survey of all participants in the study, conducted in 2010). Data have been collected on a comprehensive range of physical, psychosocial and demographic issues relating to a number of chronic conditions (including cardiovascular disease, diabetes, arthritis and mental health) and health-related risk factors (including obesity, blood pressure, smoking, diet, alcohol intake and inflammatory markers), as well as on current and past health status and medication.

The Australian Baby Boomer Population—Factors Influencing Changes to Health-Related Quality of Life Over Time

Objectives: Identify factors associated with changes to health-related quality of life (HRQoL) in baby boomers. Methods: Panel data were collected on baby boomers at two time points, 2000-2002 and 2004-2006. A fixed-effects model was used to identify associations between changes in the dependent variable (SF-36 summary scales) and changes in independent variables (health indicators/employment status). Results: Mental health problems, being out of labor force, sedentary behavior, and severe lung disease were associated with deterioration in physical and mental HRQoL. Obesity was associated with deterioration in physical HRQoL whereas cardiovascular disease was associated with deterioration in mental HRQoL. Unemployment, full-time employment, and absence of lung disease symptoms were associated with improvements in physical and mental HRQoL. Discussion: If we are to maximize the future labor participation, and HRQoL, of this cohort, it will be necessary to reduce obesity and sedentary behavior and to further investigate the association between health and employment.

Simple diffusion-constrained immunoassay for p24 protein with the sensitivity of nucleic acid amplification for detecting acute HIV infection

Nucleic acid amplification techniques have become the mainstay for ultimate sensitivity for detecting low levels of virus, including human immunodeficiency virus (HIV). As a sophisticated technology with relative expensive reagents and instrumentation, adoption of nucleic acid testing (NAT) can be cost inhibited in settings in which access to extreme sensitivity could be clinically advantageous for detection of acute infection. A simple low cost digital immunoassay was developed for the p24 capsid protein of HIV based on trapping enzyme-labeled immunocomplexes in high-density arrays of femtoliter microwells and constraining the diffusion of the enzyme-substrate reaction. The digital immunoassay was evaluated for analytical sensitivity for HIV capsid protein p24, and compared with commercially available NAT methods and immunoassays for p24, including 4th-generation antibody/antigen combo assays, for early detection of HIV in infected individuals. The digital immunoassay was found to exhibit 2000-3000-fold greater analytical sensitivity than conventional immunoassays reactive for p24, and comparable sensitivity to NAT methods. Assaying serial samples from 10 HIV-infected individuals, the digital immunoassay detected acute HIV infection as early as NAT methods, and 7-10 days earlier than conventional immunoassays. Comparison of assay results between the digital immunoassay and a quantitative NAT method from HIV infected serum exhibited a linear correlation R(2)>0.99. The data indicate that by constraining diffusion of the signal generation step of a simple sandwich immunoassay and enabling the digital counting of immunocomplexes, dramatic improvements in sensitivity to virus can be obtained to match the sensitivity of NAT at a fraction of the cost.

Tau proteins in serum predict neurological outcome after hypoxic brain injury from cardiac arrest: results of a pilot study

OBJECTIVE

To conduct a pilot study to evaluate the prognostic potential of serum tau protein measurements to predict neurological outcome 6 months following resuscitation from cardiac arrest.

METHODS

In this retrospective observational study, we employed a new ultra sensitive digital immunoassay technology to examine serial serum samples from 25 cardiac arrest patients to examine tau release into serum as a result of brain hypoxia, and probe for its significance predicting six-month neurological outcome. Serial blood samples were obtained from resuscitated cardiac arrest survivors during their first five days in an intensive care unit, and serum total tau was measured. Cerebral function assessments were made using Cerebral Performance Categorization (CPC) at discharge from the ICU and six months later. Tau data were analyzed in the context of 6-month CPC scores.

RESULTS

Tau elevations ranged from modest (<10 pg/mL) to very high (hundreds of pg/mL), and exhibited unexpected bi-modal kinetics in some patients. Early tau elevations appeared within 24h of cardiac arrest, and delayed elevations appeared after 24-48 h. In patients with delayed elevations, areas under the curves of tau concentration vs. hours since cardiac arrest were highly predictive of 6-month outcome (P<0.0005).

CONCLUSION

High-sensitivity serum tau measurements combined with an understanding of tau release kinetics could have utility for hypoxic brain injury assessment and prediction of cerebral function outcome.

Isolation and detection of single molecules on paramagnetic beads using sequential fluid flows in microfabricated polymer array assemblies

We report a method for isolating individual paramagnetic beads in arrays of femtolitre-sized wells and detecting single enzyme-labeled proteins on these beads using sequential fluid flows in microfabricated polymer array assemblies. Arrays of femtolitre-sized wells were fabricated in cyclic olefin polymer (COP) using injection moulding based on DVD manufacturing. These arrays were bonded to a complementary fluidic structure that was also moulded in COP to create an enclosed device to allow delivery of liquids to the arrays. Enzyme-associated, paramagnetic beads suspended in aqueous solutions of enzyme substrate were delivered fluidically to the array such that one bead per well was loaded by gravity. A fluorocarbon oil was then flowed into the device to remove excess beads from the surface of the array, and to seal and isolate the femtolitre-sized wells containing beads and enzyme substrate. The device was then imaged using standard fluorescence imaging to determine which wells contained single enzyme molecules. The analytical performance of this device as the detector for digital ELISA compared favourably to the standard method, i.e., glass arrays mechanically sealed against a silicone gasket; prostate specific antigen (PSA) could be detected from 0.011 pg mL(-1) up to 100 pg mL(-1). The use of an enclosed fluidic device to isolate beads in single-molecule arrays offers a multitude of advantages for low-cost manufacturing, ease of automation, and instrument development to enable applications in biomarker validation and medical diagnosis.

Single molecule enzyme-linked immunosorbent assays: theoretical considerations

We have developed a highly sensitive immunoassay-called digital ELISA-that is based on the detection of single enzyme-linked immunocomplexes on beads that are sealed in arrays of femtoliter wells. Digital ELISA was designed to be highly efficient in the capturing of target proteins, labeling of these proteins, and their detection in single molecule arrays (SiMoA); in essence, the goal of the assay is to "capture every molecule, detect every molecule". Here we provide the theoretical basis for the design of this assay derived from simple equations based on bimolecular interactions. Using these equations and knowledge of the concentrations of reagents, the times of interactions, and the on- and off-rates of the molecular interactions for each step of the assay, it is possible to predict the number of immunocomplexes that are formed and detected by SiMoA. The unique ability of SiMoA to count single immunocomplexes and determine an average number of enzymes per bead (AEB), makes it possible to directly compare the number of molecules detected experimentally to those predicted by theory. These predictions compare favorably to experimental data generated for a digital ELISA for prostate specific antigen (PSA). The digital ELISA process is efficient across a range of antibody affinities (K(D)~10(-11) -10(-9) M), and antibodies with high on-rates (k(on)>10(5) M(-1) s(-1)) are predicted to perform best. The high efficiency of digital ELISA and sensitivity of SiMoA to enzyme label also makes it possible to reduce the concentration of labeling reagent, reduce backgrounds, and increasing the specificity of the approach. Strategies for dealing with the dissociation of antibody complexes over time that can affect the signals in an assay are also described.

Investigating obstructive sleep apnoea: will the health system have the capacity to cope? A population study

Objective. To obtain prevalence estimates of clinical features of obstructive sleep apnoea (OSA) and identify the dimensions of the public health problem requiring further investigation for an Australian population. Methods. The South Australian Health Omnibus Survey is an annual representative population survey of South Australians aged ≥15 years, conducted via interviewer-administered questionnaire. In 2009, 3007 participants were asked the STOP-BANG instrument measure of obstructive sleep apnoea risk, which includes symptoms of loud snoring, frequent tiredness during daytime, observed apnoea, and high blood pressure (STOP), and measured body mass index, age, neck circumference and gender (BANG). Three or more positive response categorises a person at high risk for OSA. Results. Snoring was reported by 49.7% of adults. Tiredness after sleep more than 3 – 4 times per week was reported by 24.8%, and during wake-time by 27.7% of adults, with 8.8% reporting having fallen asleep while driving. Over half of the surveyed men (57.1%, n = 566) and 19.3% (n = 269) of the women were classified at high-risk of OSA with the STOP-BANG measure. In multivariable models, high risk was associated with less education, lower income, and residence in a regional rather than metropolitan area. Conclusion. The high prevalence of adults at risk for OSA suggests that the capacity currently available within the healthcare system to investigate and diagnose OSA is likely to be inadequate, particularly outside urban areas. This highlights an important public health problem that requires further detailed study and trials of new models of care. What is known about the topic? Obstructive sleep apnoea (OSA) is associated with obesity, and although it is associated with significant morbidity and mortality there is no simple clinical test for this condition. While the prevalence of snoring or sleepiness is reported to be high and increasing with obesity, there is little recent information on how many adults report combinations of frequent sleep-related breathing abnormalities, unsatisfactory sleep, or unexplained daytime sleepiness, that justify further investigation with tests such as polysomnography that require considerable health service investment. What does this paper add? In a representative adult population sample of 3007 adults, 27.8% were classified at high risk of OSA with a validated screening tool that uses symptoms and body measurements (STOP-BANG). Risk was greater with lower income and education, and residence outside of metropolitan areas. What are the implications for practitioners? Clinicians need to be aware that over a quarter of adults may need investigation for OSA, and should adopt an active approach to identifying people at risk. Health services and policy makers need to plan for this problem, and innovative approaches to provision of investigation and management need to be trialled.

Fifth-generation digital immunoassay for prostate-specific antigen by single molecule array technology

BACKGROUND

Measurement of prostate-specific antigen (PSA) in prostate cancer patients following radical prostatectomy (RP) has been hindered by the limit of quantification of available assays. Because radical prostatectomy removes the tissue responsible for PSA production, postsurgical PSA is typically undetectable with current assay methods. Evidence suggests, however, that more sensitive determination of PSA status following RP could improve assessment of patient prognosis and response to treatment and better target secondary therapy for those who may benefit most. We developed an investigational digital immunoassay with a limit of quantification 2 logs lower than current ultrasensitive third-generation PSA assays.

METHODS

We developed reagents for a bead-based ELISA for use with high-density arrays of femtoliter-volume wells. Anti-PSA capture beads with immunocomplexes and associated enzyme labels were singulated within the wells of the arrays and interrogated for the presence of enzymatic product. We characterized analytical performance, compared its accuracy with a commercially available test, and analyzed longitudinal serum samples from a pilot study of 33 RP patients.

RESULTS

The assay exhibited a functional sensitivity (20% interassay CV) <0.05 pg/mL, total imprecision <10% from 1 to 50 pg/mL, and excellent agreement with the comparator method. All RP samples were well within the assay measurement capability. PSA concentrations following surgery were found to be predictive of prostate cancer recurrence risk over 5 years.

CONCLUSIONS

The robust 2-log improvement in limit of quantification relative to current ultrasensitive assays and the validated analytical performance of the assay allow for accurate assessment of PSA status after RP.

Single molecule measurements of tumor necrosis factor α and interleukin-6 in the plasma of patients with Crohn's disease

The quantitative measurement of inflammatory cytokines in blood has been limited by insufficient sensitivity of conventional immunoassays. This limitation has prevented the widespread clinical monitoring of cytokine concentrations in chronic inflammatory diseases. We applied a sensitive, single molecule detection technology to measure TNF-α and IL-6 in the plasma of patients with Crohn's disease (CD), before and after treatment with anti-TNF-α therapy. Plasma from 17 patients with CD was collected prior to initiation of anti-TNF-α therapy, and the Crohn's disease activity index (CDAI) was determined for each patient. A sub-set of these patients returned for follow up 12 weeks after treatment started. Plasma from age- and gender-matched controls was also collected. Digital ELISAs were developed for TNF-α and IL-6, and the plasma concentrations of these cytokines were determined using digital ELISA. The limits of detection of the TNF-α and IL-6 digital ELISAs were 0.008 pg/mL and 0.006 pg/mL, respectively. Both cytokines were detected in all samples using digital ELISA and the concentrations of TNF-α and IL-6 in the plasma of patients with CD were (3.6±0.9) pg/mL and (10.9±11.2) pg/mL, respectively. TNF-α levels in patients and healthy controls were not significantly different, but the IL-6 levels in plasma were significantly elevated in patients compared to controls. After therapy, the mean reduction of the concentrations of free TNF-α and IL-6 were 46% and 58%, respectively. Digital ELISA provided the first quantitative measurements of TNF-α and IL-6 concentrations in the plasma of all patients in a population with CD. The changes in cytokine concentrations after therapy--which could be quantified because of the high sensitivity of digital ELISA--could be used for monitoring therapeutic efficacy.

Cause for concern in the use of non-steroidal anti-inflammatory medications in the community--a population-based study

BACKGROUND

Non-steroidal anti-inflammatory (NSAID) medications are a common cause of reported adverse drug side-effects. This study describes the prevalence of non-steroidal anti-inflammatory (NSAID) use (other than low-dose aspirin) and the presence of co-existing relative contraindications to NSAID use and chronic conditions in a representative population sample.

METHODS

Data were analysed from 3,206 adults attending first follow-up of the North West Adelaide Health Study (NWAHS) in 2004-2006, a longitudinal representative population study. Medications were brought into study clinic visits by participants. Clinical assessment included measured blood pressure, kidney function, serum cholesterol, blood glucose. Questionnaires assessed demographics, lifestyle risk factors, physician-diagnosed chronic conditions. Data were weighted to census measures by region, age group, gender, and probability of selection in the household, to provide population representative estimates. Pearson's Chi-square tests determined significant differences in proportions. Multiple logistic regression was used to examine associations of socio-demographic characteristics with use of NSAIDs.

RESULTS

Of 3,175 participants, 357 (11.2%), and 16% of those aged > 55 years, reported using either non-specific NSAIDs or COX-2 inhibitors, other than low-dose aspirin. Among people using NSAIDs, 60.8% had hypertension, 30.8% had Stage 3 or higher chronic kidney disease, 17.2% had a history of cardiovascular disease (CVD) and 20.7% had a > 15% 10-year CVD risk. The prevalence of NSAID use among people with hypertension was 16%, with kidney disease 15.9%, and a history of CVD 20.0%. Among people taking diuretics, 24.1% were also taking NSAIDs, and of those taking medications for gastro-esophageal reflux, 24.7% were on NSAIDs. Prescription-only COX-2 inhibitors, but not other NSAIDs, were used more by people > 75 years than by 35-54 year olds (OR 3.7, 95% CI 2.0, 6.7), and also were more commonly used by people with hypertension, cardiac and kidney disease.

CONCLUSIONS

There is a high prevalence of current NSAID use among groups at-risk for significant drug-related adverse events or who have major chronic conditions that are relative contraindications to NSAID use. Assessment of absolute risks regarding cardiovascular and kidney disease need to take into account use of medications such as NSAIDs. The potential to make a substantial impact on chronic disease burden via improved use of NSAIDs is considerable.

Simultaneous detection of single molecules and singulated ensembles of molecules enables immunoassays with broad dynamic range

We report a method for combining the detection of single molecules (digital) and an ensemble of molecules (analog) that is capable of detecting enzyme label from 10(-19) M to 10(-13) M, for use in high sensitivity enzyme-linked immunosorbent assays (ELISA). The approach works by capturing proteins on microscopic beads, labeling the proteins with enzymes using a conventional multistep immunosandwich approach, isolating the beads in an array of 50-femtoliter wells (Single Molecule Array, SiMoA), and detecting bead-associated enzymatic activity using fluorescence imaging. At low concentrations of proteins, when the ratio of enzyme labels to beads is less than ∼1.2, beads carry either zero or low numbers of enzymes, and protein concentration is quantified by counting the presence of "on" or "off" beads (digital regime). (1) At higher protein concentrations, each bead typically carries multiple enzyme labels, and the average number of enzyme labels present on each bead is quantified from a measure of the average fluorescence intensity (analog regime). Both the digital and analog concentration ranges are quantified by a common unit, namely, average number of enzyme labels per bead (AEB). By combining digital and analog detection of singulated beads, a linear dynamic range of over 6 orders of magnitude to enzyme label was achieved. Using this approach, an immunoassay for prostate specific antigen (PSA) was developed. The combined digital and analog PSA assay provided linear response over approximately four logs of concentration ([PSA] from 8 fg/mL to 100 pg/mL or 250 aM to 3.3 pM). This approach extends the dynamic range of ELISA from picomolar levels down to subfemtomolar levels in a single measurement.

Depression and obesity in adults with asthma: multiple comorbidities and management issues

OBJECTIVE

To examine the comparative prevalence and distribution of obesity and psychological disturbance in the asthma and non-asthma populations, and to determine how these comorbidities are associated with physical functioning.

DESIGN, SETTING AND PARTICIPANTS

A South Australian population-representative study of 3175 adults who provided data on asthma, psychological morbidity, physical functioning, and body mass index. Bivariate and multivariate analyses identified how these comorbidities were distributed in asthma and non-asthma subpopulations, and the variance in physical functioning that they explained.

MAIN OUTCOME MEASURES

Rates of obesity and psychological morbidity, and physical functioning scores in asthma and non-asthma populations.

RESULTS

Men and women in the asthma population had similar prevalences of obesity (35.3% v 33.6%) and psychological morbidity (29.5% v 29.4%). When compared with non-asthma controls, both comorbidities were significantly higher only in men with asthma. The prevalence of psychological morbidity within different weight categories in the asthma population compared with non-asthma weight-category controls varied by sex. Physical functioning was lower in the asthma population than the non-asthma population (46.6 [95% CI, 45.9-47.3] v 48.8 [95% CI, 47.8-50.0]; P < 0.001), and psychological morbidity explained 22% of this variance.

CONCLUSIONS

Psychological morbidity and obesity are common in people with asthma. The sex-specific variation in psychological morbidity across weight categories suggests that future studies of psychological morbidity in groups with asthma should adopt designs that consider sex-specific controls rather than comparisons between the sexes.

Hormone therapy use after the Women's Health Initiative

OBJECTIVE

To continue surveillance of hormone therapy (HT) use in an Australian population and to assess the impact of the Women's Health Initiative (WHI) and associated reports on HT use 16 months after the results of the WHI were first reported.

METHODS

Data were obtained from the 2003 South Australian Health Omnibus Survey, which involves a representative, population face-to-face interview survey. Data were compared to five surveys undertaken between 1991 and 2000, which had consistent methods and quality-control procedures. A total of 907 interviews were conducted with women over 40 years in their own homes by trained health interviewers.

RESULTS

In association with the timing of media reporting of the WHI, current HT use rates dropped from 28% in women over 50 years in 2000 to an estimated 10.2% in 2002. By October 2003, current use rates had returned to 18.8% in this age group. The media had been the main influence in the women's decision-making. Half of those who restarted therapy changed to another type of HT. Only 2.8% changed to an alternative/complementary therapy.

CONCLUSIONS

Nearly two-thirds (64%) of those currently using HT in 2002 stopped therapy, mostly in response to the media reporting of the WHI. Nearly half of those who stopped HT in 2002 have since restarted. Media reporting greatly influences the use of hormonal therapies.

Global Initiative for Chronic Obstructive Lung Disease stage 0 is associated with excess FEV(1) decline in a representative population sample

BACKGROUND

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guideline removed stage 0 (chronic cough and sputum without airflow obstruction, GOLD-0) because of poor prognostic value. Preventative intervention may be relevant for those with chronic symptoms; therefore, we assessed the stability, morbidity, and FEV(1) decline associated with GOLD stage 0 in a representative adult population cohort.

METHODS

Baseline (n = 4,060) and follow-up (n = 3,206, mean 3.5 years) clinic assessment of the North West Adelaide Health Study included postbronchodilator spirometry, anthropometry, and measures of doctor-diagnosed asthma, respiratory symptoms, smoking status, quality of life, and depression.

RESULTS

Baseline GOLD-0 prevalence was 17.0% (n = 584). At follow-up (n = 420), 39.8% remained stable, 1.4% progressed to GOLD stages 1 to 2, and 58.8% resolved to no symptoms. Persistent GOLD-0 at follow-up was associated with persistent smoking (men: odds ratio [OR] = 11.9, 95% CI, 6.4-22.1; women: OR = 4.0, 95% CI, 2.1-7.4), and depressive symptoms (men: OR = 3.8, 95% CI, 1.9-7.6; women: OR = 3.2, 95% CI, 1.7-5.9), with highest quartile of FEV(1) decline (mL) per year (OR = 2.1, 95% CI, 1.2-3.7) and the metabolic syndrome (OR = 1.7, 95% CI, 1.01-3.0) in men, and with older age in women. These associations generally held in smokers and never-smokers. Resolving GOLD-0 was associated with smoking cessation (OR = 13.7; 95% CI, 4.6-40.1), FEV(1) decline (mL) per year below the median (OR = 2.0; 95% CI, 1.1-3.5), normal BMI, and younger age groups. Sensitivity analyses based on the presence of sputum did not change the observed associations.

CONCLUSION

Persistent GOLD-0 identified people with physical and psychologic morbidity in both smokers and nonsmokers. Identification of those with persistent respiratory symptoms is therefore important. Excess FEV(1) decline in men suggests GOLD-0 may identify a group at risk to progress to COPD over time.

Associations of physical and mental health problems with chronic cough in a representative population cohort

Background

Although chronic cough is a common problem in clinical practice, data on the prevalence and characteristics of cough in the general population are scarce. Our aim was to determine the prevalence of chronic cough that is not associated with diagnosed respiratory conditions and examine the impact on health status and psychological health, in a representative adult population cohort

Methods

North West Adelaide Health Study (n stage 1 = 4060, stage 2 = 3160) is a representative population adult cohort. Clinical assessment included spirometry, anthropometry and skin tests. Questionnaires assessed demographics, lifestyle risk factors, quality of life, mental health and respiratory symptoms, doctor diagnosed conditions and medication use.

Results

Of the 3355 people without identified lung disease at baseline, 18.2% reported chronic cough. In multiple logistic regression models, at follow-up, dry chronic cough without sputum production was significantly more common in males (OR 1.5, 95% CI 1.1, 1.9), current smokers (OR 4.9, 95% CI 3.4, 7.2), obesity (OR 1.9, 95% CI 1.3, 2.9), use of ACE inhibitors (OR 1.8, 95% CI 1.1, 2.9), severe mental health disturbance (OR 2.1, 95% CI 1.4, 3.1) and older age (40-59 years OR 1.7 95% CI 1.2, 2.4; ≥ 60 years OR 2.1 95% CI 1.3, 3.5). Among non-smokers only, all cough was significantly more common in men, those with severe mental health disturbance and obesity.

Conclusions

Chronic cough is a major cause of morbidity. Attention to cough is indicated in patients with obesity, psychological symptoms or smokers. Inquiring about cough in those with mental health problems may identify reversible morbidity.

Gender differences in asthma prevalence: variations with socioeconomic disadvantage

BACKGROUND AND OBJECTIVE

Socioeconomic inequalities in health have been shown to vary for different diseases and by gender. This study aimed to examine gender differences in associations between asthma and socioeconomic disadvantage.

METHODS

Socioeconomic variables were assessed among men and women in the North West Adelaide Health Study, a representative population cohort (n = 4060) aged 18 years and over in metropolitan South Australia. Asthma was determined from spirometry and self-reported doctor diagnosis.

RESULTS

The prevalence of asthma was 12.0% (95% CI: 11.1-13.1), and was significantly higher among women (13.5%) than men (10.5%). For participants aged 18-64 years a higher prevalence of asthma was associated with an education level of secondary school or lower, or not being in the paid labour force among men, and with a gross annual household income of $20,000 or less among women. Among socioeconomically advantaged groups, the prevalence of asthma was significantly higher among women than men.

CONCLUSIONS

Socioeconomic disadvantage was associated with higher asthma prevalence, although this varied by gender depending on the indicator of socioeconomic position used. Men with low education or those not employed in the paid labour force had higher asthma prevalence than more socioeconomically advantaged men. Women with low income had higher asthma prevalence than those with higher income. Among all socioeconomically advantaged groups, and also the low-income group, women experienced a higher prevalence of asthma than men.

Effects of area deprivation on health risks and outcomes: a multilevel, cross-sectional, Australian population study

OBJECTIVES

Our aim was to examine the effect of local area socio-economic disadvantage after accounting for individual socio-economic status (SES), and to determine if these differ between various health and risk factor variables.

METHODS

The North West Adelaide Health Study (NWAHS) is a biomedical representative population study of adults. The Index of Relative Socio-Economic Disadvantage (IRSD), produced from the Australian Bureau of Statistics (ABS) Census data at the level of Collector Districts (200 dwellings) was used as an indicator of local area disadvantage. Multi-level modeling techniques examined the effects of IRSD level on a variety of health outcomes and risk factors, after accounting for individual socio-economic factors.

RESULTS

Significant, independent associations were seen between IRSD and obesity, smoking, and health-related quality of life, with 5 % to 7.2 % of the variance located at the neighborhood level. No independent associations were seen between IRSD and estimated cardiovascular disease risk, diabetes, physical activity, or at-risk alcohol use.

CONCLUSIONS

Aggregated area-level characteristics make modest, but significant independent contributions to smoking, obesity and quality of life, but not for other health outcomes.

Medicare-related service use and costs among people with diagnosed and undiagnosed diabetes and respiratory conditions

OBJECTIVE

To compare Medicare-related costs and service utilisation of people with diagnosed diabetes, asthma or chronic obstructive pulmonary disease (COPD) to those who were previously undiagnosed, and those without these conditions.

DESIGN, SETTING AND PARTICIPANTS

Representative cross-sectional study of people (18+ years) living in the north-west area of Adelaide. Participants were recruited by telephone interviews. Biomedical and self-report data for 2352 participants were linked to Medicare Australia Medicare Benefits Schedule (MBS) data from 1997 to 2002.

MAIN OUTCOME MEASURES

Mean number and cost (benefit paid) of MBS services for people with diagnosed and previously undiagnosed diabetes, asthma, and COPD, and those without these conditions.

RESULTS

Mean (+/- SD) MBS costs were significantly greater for people diagnosed with diabetes ($4205 +/- 2596), asthma ($3307 +/- 2542), or COPD ($3779 +/- 2529) than for those without these conditions. MBS costs for people with asthma or COPD that had not yet been diagnosed were also significantly higher than for those without these conditions, although this was inconsistent across financial years.

CONCLUSIONS

Diabetes, asthma, and COPD are costly conditions in terms of health service use. Costs associated with undiagnosed asthma and COPD are similar to their diagnosed states. Prevention of progression along each chronic disease continuum is likely to reduce costs.

Health literacy--a new concept for general practice?

BACKGROUND

Health literacy is the ability to understand and interpret the meaning of health information in written, spoken or digital form and how this motivates people to embrace or disregard actions relating to health.

OBJECTIVE

This article aims to describe the concept of health literacy, its importance and its applications in the general practice setting.

DISCUSSION

Australia trails behind other western countries in practical applications of health literacy. Health literacy underpins the efficiency of consultations, health promotion efforts, and self management programs. Recognition of the health literacy status of individuals allows use of appropriate communication tools. This can save time and effort and improve patient satisfaction and health outcomes.