NT-ProBNP levels in saliva and its clinical relevance to heart failure

Background: Current blood based diagnostic assays to detect heart failure (HF) have large intra-individual and inter-individual variations which have made it difficult to determine whether the changes in the analyte levels reflect an actual change in disease activity. Human saliva mirrors the body's health and well being and similar to 20% of proteins that are present in blood are also found in saliva. Saliva has numerous advantages over blood as a diagnostic fluid which allows for a non-invasive, simple, and safe sample collection. The aim of our study was to develop an immunoassay to detect NT-proBNP in saliva and to determine if there is a correlation with blood levels. Methods: Saliva samples were collected from healthy volunteers (n = 40) who had no underlying heart conditions and HF patients (n = 45) at rest. Samples were stored at -80 degrees C until analysis. A customised homogeneous sandwich AlphaLISA((R)) immunoassay was used to quantify NT-proBNP levels in saliva. Results: Our NT-proBNP immunoassay was validated against a commercial Roche assay on plasma samples collected from HF patients (n = 37) and the correlation was r(2) = 0.78 (p<0.01, y = 1.705 x +1910.8). The median salivary NT-proBNP levels in the healthy and HF participants were <16 pg/mL and 76.8 pg/mL, respectively. The salivary NT-proBNP immunoassay showed a clinical sensitivity of 82.2% and specificity of 100%, positive predictive value of 100% and negative predictive value of 83.3%, with an overall diagnostic accuracy of 90.6%. Conclusion: We have firstly demonstrated that NT-proBNP can be detected in saliva and that the levels were higher in heart failure patients compared with healthy control subjects. Further studies will be needed to demonstrate the clinical relevance of salivary NT-proBNP in unselected, previously undiagnosed populations.

Circulating fragments of N-Terminal Pro-B-Type Natriuretic Peptides in plasma of heart failure patients

BACKGROUND: The use of nonstandardized N-terminal pro-B-type natriuretic peptide (NT-proBNP) assays can contribute to the misdiagnosis of heart failure (HF). Moreover, there is yet to be established a common consensus regarding the circulating forms of NT-proBNP being used in current assays. We aimed to characterize and quantify the various forms of NT-proBNP in the circulation of HF patients. METHODS: Plasma samples were collected from HF patients (n = 20) at rest and stored at -80 degrees C. NT-proBNP was enriched from HF patient plasma by use of immunoprecipitation followed by mass spectrometric analysis. Customized homogeneous sandwich AlphaLISA (R) immunoassays were developed and validated to quantify 6 fragments of NT-proBNP. RESULTS: Mass spectrometry identified the presence of several N- and C-terminally processed forms of circulating NT-proBNP, with physiological proteolysis between Pro2-Leu3, Leu3-Gly4, Pro6-Gly7, and Pro75-Arg76. Consistent with this result, AlphaLISA immunoassays demonstrated that antibodies targeting the extreme N or C termini measured a low apparent concentration of circulating NT-proBNP. The apparent circulating NT-proBNP concentration was increased with antibodies targeting nonglycosylated and nonterminal epitopes (P < 0.05). CONCLUSIONS: In plasma collected from HF patients, immunoreactive NT-proBNP was present as multiple N- and C-terminally truncated fragments of the full length NT-proBNP molecule. Immunodetection of NT-proBNP was significantly improved with the use of antibodies that did not target these terminal regions. These findings support the development of a next generation NT-proBNP assay targeting nonterminal epitopes as well as avoiding the central glycosylated region of this molecule. (c) 2013 American Association for Clinical Chemistry

A rapid and cost-effective method of producing recombinant proBNP and NT-proBNP variants in Escherichia coli for immunoassay of heart failure

The measurements of plasma natriuretic peptides (NT-proBNP, proBNP and BNP) are used to diagnose heart failure but these are expensive to produce. We describe a rapid, cheap and facile production of proteins for immunoassays of heart failure. DNA encoding N-terminally His-tagged NT-proBNP and proBNP were cloned into the pJexpress404 vector. ProBNP and NT-proBNP peptides were expressed in Escherichia coli, purified and refolded in vitro. The analytical performance of these peptides were comparable with commercial analytes (NT-proBNP EC50 for the recombinant is 2.6 ng/ml and for the commercial material is 5.3 ng/ml) and the EC50 for recombinant and commercial proBNP, are 3.6 and 5.7 ng/ml respectively). Total yield of purified refolded NT-proBNP peptide was 1.75 mg/l and proBNP was 0.088 mg/l. This approach may also be useful in expressing other protein analytes for immunoassay applications. To develop a cost effective protein expression method in E. coli to obtain high yields of NT-proBNP (1.75 mg/l) and proBNP (0.088 mg/l) peptides for immunoassay use.

Citizen’s right to the digital city: Urban interfaces, activism, and placemaking

Edited by thought leaders of the fields of urban informatics and urban interaction design, this book brings together case studies and examples from around the world to discuss the role that urban Interfaces, citizen action, and city making play in the quest to create and maintain not only secure and resilient, but productive, sustainable, and liveable urban environments. The book debates the impact of these trends on theory, policy, and practice. The chapters in this book are sourced from blind peer reviewed contributions by leading researchers working at the intersection of the social / cultural, technical / digital, and physical / spatial domains of urbanism scholarship. The book appeals not only to research colleagues and students, but also to a vast number of practitioners in the private and public sector interested in accessible accounts that clearly and rigorously analyse the affordances and possibilities of urban interfaces, mobile technology, and location-based services to engage people towards open, smart and participatory urban environments.

The paradigm shift in realising the right to read : how ebook libraries are enabling in the university sector

Millions of people with print disabilities are denied the right to read. While some important efforts have been made to convert standard books to accessible formats and create accessible repositories, these have so far only addressed this crisis in an ad hoc way. This article argues that universally designed ebook libraries have the potential of substantially enabling persons with print disabilities. As a case study of what is possible, we analyse 12 academic ebook libraries to map their levels of accessibility. The positive results from this study indicate that universally designed ebooks are more than possible; they exist. While results are positive, however, we also found that most ebook libraries have some features that frustrate full accessibility, and some ebook libraries present critical barriers for people with disabilities. Based on these findings, we consider that some combination of private pressure and public law is both possible and necessary to advance the right-to-read cause. With access improving and recent advances in international law, now is the time to push for universal design and equality.

Automated power semiconductor switching performance feature extraction from experimental double-pulse waveform data

Double-pulse tests are commonly used as a method for assessing the switching performance of power semiconductor switches in a clamped inductive switching application. Data generated from these tests are typically in the form of sampled waveform data captured using an oscilloscope. In cases where it is of interest to explore a multi-dimensional parameter space and corresponding result space it is necessary to reduce the data into key performance metrics via feature extraction. This paper presents techniques for the extraction of switching performance metrics from sampled double-pulse waveform data. The reported techniques are applied to experimental data from characterisation of a cascode gate drive circuit applied to power MOSFETs.

SHM through flexible vibration sensing technologies and robust safety evaluation paradigm

This research has successfully developed a novel synthetic structural health monitoring system model that is cost-effective and flexible in sensing and data acquisition; and robust in the structural safety evaluation aspect for the purpose of long-term and frequent monitoring of large-scale civil infrastructure during their service lives. Not only did it establish a real-world structural monitoring test-bed right at the heart of QUT Gardens Point Campus but it can also facilitate reliable and prompt protection for any built infrastructure system as well as the user community involved.

Gliptins - do they increase cardiovascular risk or benefit?

INTRODUCTION: In 2008, the US FDA required all new glucose-lowering therapies to show cardiovascular safety, and this applies to the dipeptidyl peptidase-4 inhibitors ('gliptins'). AREAS COVERED: The cardiovascular safety trials of saxagliptin and alogliptin have recently been published and are the subject of this evaluation. EXPERT OPINION: The Saxagliptin Assessment of Vascular Outcomes Recorded in Patients with Diabetes Mellitus - Thrombolysis in Myocardial Infarction 53 trial and Examination of Cardiovascular Outcomes with Alogliptin versus Standard of Care were both multicentre, randomised, double-blind, placebo-controlled, Phase IV clinical trials. These trials showed that saxagliptin and alogliptin did not increase the primary end point, which was a composite of cardiovascular outcomes that did not include hospitalisations for heart failure. However, saxagliptin significantly increased hospitalisation for heart failure, which was a component of the secondary end point. The effect of alogliptin on hospitalisations for heart failure has not been reported. Neither agent improved cardiovascular outcomes. As there is no published evidence of improved outcomes with gliptins, it is unclear to us why these agents are so widely available for use. We suggest that the use of gliptins be restricted to Phase IV clinical trials until such time as cardiovascular safety and benefits/superiority are clearly established

Symptom correlates of static and dynamic facial affect processing in schizophrenia : evidence of a double dissociation?

Schizophrenia patients have been shown to be compromised in their ability to recognize facial emotion. This deficit has been shown to be related to negative symptoms severity. However, to date, most studies have used static rather than dynamic depictions of faces. Nineteen patients with schizophrenia were compared with seventeen controls on 2 tasks; the first involving the discrimination of facial identity, emotion, and butterfly wings; the second testing emotion recognition using both static and dynamic stimuli. In the first task, the patients performed more poorly than controls for emotion discrimination only, confirming a specific deficit in facial emotion recognition. In the second task, patients performed more poorly in both static and dynamic facial emotion processing. An interesting pattern of associations suggestive of a possible double dissociation emerged in relation to correlations with symptom ratings: high negative symptom ratings were associated with poorer recognition of static displays of emotion, whereas high positive symptom ratings were associated with poorer recognition of dynamic displays of emotion. However, while the strength of associations between negative symptom ratings and accuracy during static and dynamic facial emotion processing was significantly different, those between positive symptom ratings and task performance were not. The results confirm a facial emotion-processing deficit in schizophrenia using more ecologically valid dynamic expressions of emotion. The pattern of findings may reflect differential patterns of cortical dysfunction associated with negative and positive symptoms of schizophrenia in the context of differential neural mechanisms for the processing of static and dynamic displays of facial emotion.

Double-strand breaks and the concept of short- and long-term epigenetic memory

Double-strand breaks represent an extremely cytolethal form of DNA damage and thus pose a serious threat to the preservation of genetic and epigenetic information. Though it is well-known that double-strand breaks such as those generated by ionising radiation are among the principal causative factors behind mutations, chromosomal aberrations, genetic instability and carcino-genesis, significantly less is known about the epigenetic consequences of double-strand break formation and repair for carcinogenesis. Double-strand break repair is a highly coordinated process that requires the unravelling of the compacted chromatin structure to facilitate repair machinery access and then restoration of the original undamaged chromatin state. Recent experimental findings have pointed to a potential mechanism for double-strand break-induced epigenetic silencing. This review will discuss some of the key epigenetic regulatory processes involved in double-strand break (DSB) repair and how incomplete or incorrect restoration of chromatin structure can leave a DSB-induced epigenetic memory of damage with potentially pathological repercussions

Evaluation of the efficacy of radiation-modifying compounds using γH2AX as a molecular marker of DNA double-strand breaks

Radiation therapy is a widely used therapeutic approach for cancer. To improve the efficacy of radiotherapy there is an intense interest in combining this modality with two broad classes of compounds, radiosensitizers and radioprotectors. These either enhance tumour-killing efficacy or mitigate damage to surrounding non-malignant tissue, respectively. Radiation exposure often results in the formation of DNA double-strand breaks, which are marked by the induction of H2AX phosphorylation to generate γH2AX. In addition to its essential role in DDR signalling and coordination of double-strand break repair, the ability to visualize and quantitate γH2AX foci using immunofluorescence microscopy techniques enables it to be exploited as an indicator of therapeutic efficacy in a range of cell types and tissues. This review will explore the emerging applicability of γH2AX as a marker for monitoring the effectiveness of radiation-modifying compounds.

Methylproamine protects against ionizing radiation by preventing DNA double-strand breaks

Purpose The majority of cancer patients will receive radiotherapy (RT), therefore, investigations into advances of this modality are important. Conventional RT dose intensities are limited by adverse responses in normal tissues and a primary goal is to ameliorate adverse normal tissue effects. The aim of these experiments is to further our understanding regarding the mechanism of radioprotection by the DNA minor groove binder, methylproamine, in a cellular context at the DNA level. Materials and methods We used immunocytochemical methods to measure the accumulation of phosphorylated H2AX (γH2AX) foci following ionizing radiation (IR) in patient-derived lymphoblastoid cells exposed to methylproamine. Furthermore, we performed pulsed field gel electrophoresis DNA damage and repair assays to directly interrogate the action of methylproamine on DNA in irradiated cells. Results We found that methylproamine-treated cells had fewer γH2AX foci after IR compared to untreated cells. Also, the presence of methylproamine decreased the amount of lower molecular weight DNA entering the gel as shown by the pulsed field gel electrophoresis assay. Conclusions These results suggest that methylproamine acts by preventing the formation of DNA double-strand breaks (dsbs) and support the hypothesis that radioprotection by methylproamine is mediated, at least in part, by decreasing initial DNA damage.

H2AX phosphorylation screen of cells from radiosensitive cancer patients reveals a novel DNA double-strand break repair cellular phenotype

BACKGROUND: About 1-5% of cancer patients suffer from significant normal tissue reactions as a result of radiotherapy (RT). It is not possible at this time to predict how most patients' normal tissues will respond to RT. DNA repair dysfunction is implicated in sensitivity to RT particularly in genes that mediate the repair of DNA double-strand breaks (DSBs). Phosphorylation of histone H2AX (phosphorylated molecules are known as gammaH2AX) occurs rapidly in response to DNA DSBs, and, among its other roles, contributes to repair protein recruitment to these damaged sites. Mammalian cell lines have also been crucial in facilitating the successful cloning of many DNA DSB repair genes; yet, very few mutant cell lines exist for non-syndromic clinical radiosensitivity (RS). METHODS: Here, we survey DNA DSB induction and repair in whole cells from RS patients, as revealed by gammaH2AX foci assays, as potential predictive markers of clinical radiation response. RESULTS: With one exception, both DNA focus induction and repair in cell lines from RS patients were comparable with controls. Using gammaH2AX foci assays, we identified a RS cancer patient cell line with a novel ionising radiation-induced DNA DSB repair defect; these data were confirmed by an independent DNA DSB repair assay. CONCLUSION: gammaH2AX focus measurement has limited scope as a pre-RT predictive assay in lymphoblast cell lines from RT patients; however, the assay can successfully identify novel DNA DSB repair-defective patient cell lines, thus potentially facilitating the discovery of novel constitutional contributions to clinical RS.

Demographics and survivial of a cohort of blood and breast cancer patients who developed heart failure following cancer treatment

Background/Aim: Cardiotoxicity resulting in heart failure is a devastating complication of cancer therapy. It is possible that a patient may survive cancer only to develop heart failure (HF), which is more deadly than cancer. The aim of this project was to profile the characteristics of patients at risk of cancer treatment induced heart failure. Methods: Linked Health Data Analysis of Queensland Cancer Registry (QCR) from 1996-2009, Death Registry and Hospital Administration records for HF and chemotherapy admissions were reviewed. Index heart failure admission must have occurred after the date of cancer registry entry. Results: A total of 15,987 patients were included in this analysis; 1,062 (6.6%) had chemotherapy+HF admission (51.4% Female) and 14,925 (93.4%) chemotherapy_no HF admission. Median age of chemotherapy+HF patients was 67 years (IQR 58 to 75) vs. 54 years (IQR 44 to 64) for chemotherapy_no HF admission. Chemotherapy+HF patients had increased risk of all cause mortality (HR 2.79 [95% CI 2.58-3.02] and 1.67 [95% CI, 1.54 to 1.81] after adjusting for age, sex, marital status, country of birth, cancer site and chemotherapy dose). Index HF admission occurred within one year of cancer diagnosis in 47% of HF patients with 80% of patinets having there index admission with 3 years. The number of chemotherapy cycles was not associated with significant reduction in survival time in chemotherapy+HF patients. Mean survival for heart failure patients was 5.3 years (95% CI, 4.99 - 5.62) vs.9.57 years (95% CI, 9.47-9.68) for chemotherapy_no HF admission patients. Conclusion: All-cause mortality was 67% higher in patients diagnosed with HF following chemotherapy in adjusted analysis for covariates. Methods to improve and better coordinate of the interdisciplinary care for cancer patients with HF involving cardiologists and oncologists are required, including evidence-based guidelines for the comprehensive assessment, monitoring and management of this cohort.

In the right space : exploring the dynamics between design, environment and pedagogy

The environments that we inhabit shape our everyday lives, influencing our behaviors and responses (Manu, 2013). As we enter an immersive phase of education in which physical and digital environments become inseparable, should we reconsider the role and importance of design on pedagogical practice? This paper explores the reciprocal cause and effect of space, technology and pedagogy in shaping the design of educational experiences within Queensland University of Technology's collaborative learning spaces.