Frequency Domain Channel-Wise Attack to CNN Classifiers in Motor Imagery Brain-Computer Interfaces

OBJECTIVE

Convolutional neural network (CNN), a classical structure in deep learning, has been commonly deployed in the motor imagery brain-computer interface (MIBCI). Many methods have been proposed to evaluate the vulnerability of such CNN models, primarily by attacking them using direct temporal perturbations. In this work, we propose a novel attacking approach based on perturbations in the frequency domain instead.

METHODS

For a given natural MI trial in the frequency domain, the proposed approach, called frequency domain channel-wise attack (FDCA), generates perturbations at each channel one after another to fool the CNN classifiers. The advances of this strategy are two-fold. First, instead of focusing on the temporal domain, perturbations are generated in the frequency domain where discriminative patterns can be extracted for motor imagery (MI) classification tasks. Second, the perturbing optimization is performed based on differential evolution algorithm in a black-box scenario where detailed model knowledge is not required.

RESULTS

Experimental results demonstrate the effectiveness of the proposed FDCA which achieves a significantly higher success rate than the baselines and existing methods in attacking three major CNN classifiers on four public MI benchmarks.

CONCLUSION

Perturbations generated in the frequency domain yield highly competitive results in attacking MIBCI deployed by CNN models even in a black-box setting, where the model information is well-protected.

SIGNIFICANCE

To our best knowledge, existing MIBCI attack approaches are all gradient-based methods and require details about the victim model, e.g., the parameters and objective function. We provide a more flexible strategy that does not require model details but still produces an effective attack outcome.

The Plant Defensin Ppdef1 Is a Novel Topical Treatment for Onychomycosis

Onychomycosis, or fungal nail infection, causes not only pain and discomfort but can also have psychological and social consequences for the patient. Treatment of onychomycosis is complicated by the location of the infection under the nail plate, meaning that antifungal molecules must either penetrate the nail or be applied systemically. Currently, available treatments are limited by their poor nail penetration for topical products or their potential toxicity for systemic products. Plant defensins with potent antifungal activity have the potential to be safe and effective treatments for fungal infections in humans. The cystine-stabilized structure of plant defensins makes them stable to the extremes of pH and temperature as well as digestion by proteases. Here, we describe a novel plant defensin, Ppdef1, as a peptide for the treatment of fungal nail infections. Ppdef1 has potent, fungicidal activity against a range of human fungal pathogens, including Candida spp., Cryptococcus spp., dermatophytes, and non-dermatophytic moulds. In particular, Ppdef1 has excellent activity against dermatophytes that infect skin and nails, including the major etiological agent of onychomycosis Trichophyton rubrum. Ppdef1 also penetrates human nails rapidly and efficiently, making it an excellent candidate for a novel topical treatment of onychomycosis.

Attaining consensus on a core dataset for upper limb lymphoedema using the Delphi method: A foundational step in creating a clinical support system

Background: Lymphoedema is a condition of localised swelling caused by a compromised lymphatic system. The protein-rich fluid accumulating in the interstitial tissue can create inflammation and irreversible changes to the skin and underlying tissue. An array of methods has been used to assess and report these changes. Heterogeneity is evident in the clinic and in the literature for the domains assessed, outcomes and outcome measures selected, measurement protocols followed, methods of analysis, and descriptors used to report change. Objective: This study seeks consensus on the required items for inclusion in a core data set for upper limb lymphoedema to digitise the monitoring and reporting of upper limb lymphoedema. Methods: The breadth of outcomes and descriptors in common use were captured in prior studies by this research group. This list was refined by frequency and proposed to experts in the field (n = 70) through a two-round online modified Delphi study. These participants rated the importance of each item for inclusion in the dataset and identified outcomes or descriptors they felt were missing in Round 1. In Round 2, participants rated any new outcomes or descriptors proposed and preference for how numeric data is displayed. Results: The core dataset was confirmed on completion of Round 2. Interlimb difference as a percentage, and limb volume were preferred for graphed display over time; and descriptors for observed and palpated change narrowed from 42 to 20. Conclusion: This dataset provides the foundation to create a clinical support system for upper limb lymphoedema.

Provision of High Protein Foods Slows the Age-Related Decline in Nutritional Status in Aged Care Residents: A Cluster-Randomised Controlled Trial

OBJECTIVES

Malnutrition, particularly protein insufficiency, is common in institutionalised older adults and increases morbidity, mortality, and costs. We aimed to determine whether 12 months supplementation using high-protein foods (milk, cheese, yoghurt) prevents malnutrition in older adults.

DESIGN

Cluster randomised control study.

SETTING

Sixty Australian aged care facilities.

PARTICIPANTS

Older adults living in aged care homes (n=654, mean age 86.7±7.2 years, 72% females). Intervention Facilities randomly allocated to a high-protein (n=30 intervention) or regular (n=30 controls) menu.

MEASUREMENTS

Nutritional status assessed using the Mini Nutrition Assessment (MNA) tool and fasting morning blood samples (n=302) assayed for haemoglobin (Hb) and albumin. Food intake was monitored 3-monthly using visual plate waste assessment. Measurements at baseline and month 12 were analysed using random effects model accounting for clustering (facility), repeated measure and confounders.

RESULTS

Addition of 11g of protein as 1.5 servings of high-protein foods daily preserved nutritional status that deteriorated in controls [MNA screen (-0.68, 95%CI: -1.03, -0.32, p<0.001) and total (-0.90, 95%CI: -1.45, -0.35, p=0.001) scores], resulting in group differences in MNA screen (0.62, 95%CI: 0.17, 1.06, p=0.007) and total (0.81, 95%CI: 0.11, 1.51, p=0.023) scores and group difference in Hb (3.60g/L, 95%CI: 0.18, 7.03, p=0.039), the net result of preservation with intervention (0.19g/L, 95%CI: -2.04, 2.42, p=0.896) and a decline in controls (-3.41g/L, 95%CI: -6.01, -0.82, p=0.010). No group differences were observed for serum albumin.

CONCLUSION

Consumption of high-protein foods is a pragmatic approach to maintaining nutritional status in older adults in aged-care.

Effect of dietary sources of calcium and protein on hip fractures and falls in older adults in residential care: cluster randomised controlled trial

OBJECTIVE

To assess the antifracture efficacy and safety of a nutritional intervention in institutionalised older adults replete in vitamin D but with mean intakes of 600 mg/day calcium and <1 g/kg body weight protein/day.

DESIGN

Two year cluster randomised controlled trial.

SETTING

60 accredited residential aged care facilities in Australia housing predominantly ambulant residents.

PARTICIPANTS

7195 permanent residents (4920 (68%) female; mean age 86.0 (SD 8.2) years).

INTERVENTION

Facilities were stratified by location and organisation, with 30 facilities randomised to provide residents with additional milk, yoghurt, and cheese that contained 562 (166) mg/day calcium and 12 (6) g/day protein achieving a total intake of 1142 (353) mg calcium/day and 69 (15) g/day protein (1.1 g/kg body weight). The 30 control facilities maintained their usual menus, with residents consuming 700 (247) mg/day calcium and 58 (14) g/day protein (0.9 g/kg body weight).

MAIN OUTCOME MEASURES

Group differences in incidence of fractures, falls, and all cause mortality.

RESULTS

Data from 27 intervention facilities and 29 control facilities were analysed. A total of 324 fractures (135 hip fractures), 4302 falls, and 1974 deaths were observed. The intervention was associated with risk reductions of 33% for all fractures (121 v 203; hazard ratio 0.67, 95% confidence interval 0.48 to 0.93; P=0.02), 46% for hip fractures (42 v 93; 0.54, 0.35 to 0.83; P=0.005), and 11% for falls (1879 v 2423; 0.89, 0.78 to 0.98; P=0.04). The risk reduction for hip fractures and falls achieved significance at five months (P=0.02) and three months (P=0.004), respectively. Mortality was unchanged (900 v 1074; hazard ratio 1.01, 0.43 to 3.08).

CONCLUSIONS

Improving calcium and protein intakes by using dairy foods is a readily accessible intervention that reduces the risk of falls and fractures commonly occurring in aged care residents.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12613000228785.

Developing a maturity model for cancer multidisciplinary teams

BACKGROUND

Multidisciplinary teams (MDTs) are considered the "gold standard" of care for patients with cancer but how well they function and the role they play in decision making varies widely. Although several observational tools have been developed to evaluate MDT performance, they are resource intensive and only assess MDT performance at a static point in time. The aim of this study was to develop a validated maturity model as a self-assessment instrument for MDTs to evaluate their performance and monitor improvement over time.

METHODS

The authors used a three-phase methodology to develop a maturity model. In the first phase, using a modified Delphi technique, we identified 20 indicators (within five components), each having five levels of maturity [1]. In the second phase, further Delphi iterations were undertaken to refine the content and structure of the model. By the end of the second phase six components and 17 indicators had been established. In the third phase, the refined model was distributed to members from 11 MDTs to test for validity and reliability. 101 valid responses were received. Principal Component Analysis was used to determine the optimal number of components that fit the indicators. Factors with eigenvalue greater than one were extracted. Cronbach's alpha (α) was used to measure the internal consistency of components. Bivariate correlation analysis, measuring pair-wise relationships between indicators (r), was undertaken to assess convergent and discriminant validity.

RESULTS

Five factors were extracted from Principal Component Analysis. For the factors extracted, 16 out of 17 indicators showed loadings greater than the 0.4 threshold. All components demonstrated good levels of internal consistency (α > 0.8) and convergent validity (r > 0.6). Discriminant validity cannot be established. Ratings for ease of use (3.6/5) and usefulness (3.4/5) were considered acceptable.

CONCLUSIONS

Further work is required to establish discriminant validity and refine the components and indicators. Once further refinement and validation are completed, the maturity model should be a simple tool for MDTs to measure their performance and monitor improvement over time.

Implementation of an Electronic Medication Management System in a large tertiary hospital: a case of qualitative inquiry

BACKGROUND

Hospitals across Australia are implementing Clinical Information Systems, e.g. Electronic Medication Management Systems (EMMS) at a rapid pace to moderate health services. The benefits of the EMMS depend on the acceptance of the system by the clinicians. The study hospital used a unique patient-centric implementation strategy that was based on the guiding principle of "one patient, one chart" to avoid a patient being on a hybrid medication chart. This paper aims to study the factors facilitating or hindering the adoption of the EMMS as viewed by clinicians and the implementation team.

METHODS

Four focus groups (FG), one each for (1) doctors, (2) nurses, (3) pharmacists, and (4) implementation team, were conducted. A guide for the FG was based on the Unified Theory of Acceptance and Use of Technology (UTAUT).

RESULTS

A total of 23 unique subthemes were identified and were grouped into five main themes (1) implementation strategy, (2) organisational outcome of EMMS, (3) individual impact of EMMS, (4) IT product, and (5) organisational culture. Clinicians reported improvement in their workflow efficiency post-EMMS implementation. They also reported some challenges in using the EMMS that centered around the area of infrastructure, technical and design issues. Additionally, the implementation team highlighted two crucial factors influencing the success of EMMS implementation, namely: (1) the patient-centric implementation strategy, and (2) the organisation readiness.

CONCLUSION

Overall, this study outlines the implementation process of the EMMS in a large healthcare facility from the clinicians' and the implementation team's perspectives using UTAUT model. The result suggests that clinicians' acceptance of the EMMS was highly influenced by the unique implementation strategy (namely, patient-centric approach and clinical leadership in the implementation team). Whereas the level of adoption of EMMS by clinicians was determined by their level of perceived and realised benefits. On the other hand, a number of barriers to the adoption of EMMS were discovered, namely, general training instead of customised training based on local needs, technical and design issues and lack of availability of computer systems. It is suggested that promptly resolving these issues can improve the adoption of the EMMS.

Compliance with Standard Precautions and Its Relationship with Views on Infection Control and Prevention Policy among Healthcare Workers during COVID-19 Pandemic

Background: Standard precautions prevent the spread of infections in healthcare settings. Incompliance with infection control guidelines of healthcare workers (HCWs) may increase their risk of exposure to infectious disease, especially under pandemics. The purpose of this study was to assess the level of compliance with the infection prevention and control practices among HCWs in different healthcare settings and its relationship with their views on workplace infection control measures during the COVID-19 pandemic. Methods: Nurses in Hong Kong were invited to respond to a cross-sectional online survey, in which their views on workplace infection and prevention policy, compliance with standard precautions and self-reported health during pandemics were collected. Results: The respondents were dissatisfied with workplace infection and prevention policy in terms of comprehensiveness (62%), clarity (64%), timeliness (63%), and transparency (60%). For the protective behavior, the respondents did not fully comply with the standard precautions when they were involved in medical care. Their compliance was relatively low when having proper patient handling (54%) and performing invasive procedures (46%). A multivariate analysis model proved that the level of compliance of the standard precautions was positively associated with the satisfaction on infection control and prevention policy among high risk group (0.020; 95% CI: 0.005–0.036), while older respondents had higher level of compliance among the inpatient and outpatient groups (coefficient range: 0.065–0.076). The higher level of compliance was also significantly associated with working in designated team and having chronic condition of the respondents among high-risk and inpatient groups. Conclusions: Standard precautions are the most important elements to reduce cross-transmission among HCWs and patients while the satisfaction on infection control and prevention policy would increase the compliance among the high-risk group. An overall suboptimal compliance and poor views on the infection prevention and control guidelines is a warning signal to healthcare system especially during pandemics.

A novel method for clinical risk prediction with low-quality data

In real-world data, predictive models for clinical risks (such as adverse drug reactions, hospital readmission, and chronic disease onset) are constantly struggling with low-quality issues, namely redundant and highly correlated features, extreme category imbalances, and most importantly, a large number of missing values. In most existing work, each patient is represented as a value vector with the fixed-length from some feature space, and missing values are forced to be imputed, which introduces much noise for prediction if the data set is highly incomplete. Besides, other challenges are either remaining unresolved or only partially solved when modeling, but without a systematic approach. In this paper, we propose a novel framework to address these low-quality problems, that we first treat patients as bags with the various number of feature-value pairs, called instances, and map them to an embedding space through our proposed feature embedding method to learn from it directly. In this way, predictive models can avoid the negative impact of missing data naturally. A novel multi-instance neural network is then connected, using two computational modules to deal with the problems of correlated and redundant features: multi-head attention and attention-based multi-instance pooling. They are capable of capturing the instance correlations and locating valuable information in each instance or bag. The feature embedding and multi-instance neural network are parameterized and optimized jointly in an end-to-end manner. Moreover, the training process is under both main and auxiliary supervision with focal loss functions to avoid the caveat of a highly imbalanced label set. This proposed framework is named AMI-Net3. We evaluate it on three suitable data sets from real-world settings with different clinical risk prediction tasks: adverse drug reaction of risperidone, schizophrenia relapse, and invasive fungi infection, respectively. The comprehensive experimental results demonstrate the effectiveness and superiority of our proposed method over competitive baselines.

Clinician Assessment of Upper Limb Lymphedema: An Observational Study

Background: Clinical management of lymphedema requires assessment, initially for detection, and then for determining treatment response and informing the treatment plan. It is unknown how the components of a lymphedema assessment are used in a clinical environment. Methods and Results: Experienced lymphedema therapists were observed assessing patients presenting with new or existing upper body lymphedema. Occupational and physiotherapists specializing in lymphedema management (n = 14) from public and private, rural and urban settings in Australia were visited at their work sites and observed with a minimum of two patients. In total, 37 upper limb assessments were observed. Reasons for attendance included: initial assessment with new swelling (n = 4); screening/detection for possible lymphedema (n = 3); bandaging as part of an intensive treatment program (n = 2); and review (n = 28). Clinicians were observed, in order of frequency, using (1) patient-reported outcomes, (2) palpation, (3) visual assessment, (4) assessment of limb size using circumference measurements, and (5) assessment of extracellular fluid using bioimpedance spectroscopy. Although clinicians selected similar assessments, differences were observed in the measurement protocols and informed reported. Objective assessment was commonly absent when the time available for an appointment was 30 minutes. Conclusions: While clinicians spent a significant portion of an appointment time assessing the limb, a standardized approach to the assessment of lymphedema was not observed. In the absence of a standardized assessment set, therapists have developed bespoke assessment routines.

Assessment of Upper Limb Lymphedema: A Qualitative Study Exploring Clinicians' Clinical Reasoning

Background: A variety of objective and subjective assessments are available for clinical assessment of lymphedema. The aim of this study was to explore the clinical reasoning underpinning the assessment of upper limb lymphedema by experienced lymphedema clinicians. Methods and Results: Semistructured, individual, interviews were conducted with lymphedema therapists (n = 14) from a variety of treatment settings. These interviews were conducted after observations of these therapists assessing patients with lymphedema and focused on: (1) the therapists' rationale for the assessments selected, (2) how the data were analyzed, and (3) how the information was then used. Assessment selection was guided by the purpose of the visit, patient preference, resources, and time available. Subjective measures of visible and palpated tissue changes were used to target treatment, and objective measures of circumference and bioimpedance spectroscopy and patient report of symptoms informed treatment evaluation and disease progression. Objective data collected were primarily analyzed for interlimb difference and change between appointments. Conclusions: A range of clinical assessments were used in the evaluation of lymphedema to detect the presence of lymphedema, estimate the extent of soft tissue change, understand the patient experience of lymphedema, and evaluate treatment response. A primary determinant for the collection of objective measures was the appointment duration. Current methods of data analysis and reporting do not facilitate the review of change over time.

Improving the Digestibility of Plant Defensins to Meet Regulatory Requirements for Transgene Products in Crop Protection

Despite the use of chemical fungicides, fungal diseases have a major impact on the yield and quality of plant produce globally and hence there is a need for new approaches for disease control. Several groups have examined the potential use of antifungal plant defensins for plant protection and have produced transgenic plants expressing plant defensins with enhanced resistance to fungal disease. However, before they can be developed commercially, transgenic plants must pass a series of strict regulations to ensure that they are safe for human and animal consumption as well as the environment. One of the requirements is rapid digestion of the transgene protein in the gastrointestinal tract to minimize the risk of any potential allergic response. Here, we examine the digestibility of two plant defensins, NaD1 from Nicotiana alata and SBI6 from soybean, which have potent antifungal activity against major cereal pathogens. The native defensins were not digestible in simulated gastrointestinal fluid assays. Several modifications to the sequences enhanced the digestibility of the two small proteins without severely impacting their antifungal activity. However, these modified proteins did not accumulate as well as the native proteins when transiently expressed in planta, suggesting that the protease-resistant structure of plant defensins facilitates their stability in planta.

Developing a performance matrix for multidisciplinary teams

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Background: While multidisciplinary teams (MDTs) are considered the “gold standard” of care for cancer patients, their performance varies widely. This study aimed to develop a user friendly, reliable and valid self-assessment tool for MDTs to evaluate their performance and monitor improvement over time. Methods: Using maturity modelling methodology, key themes from the literature were developed into a 2-dimensional matrix comprising 17 indicators (within 6 components) across 5 levels of performance. A modified Delphi methodology (where 38 MDT members each assigned the contents to components and performance levels using card sorting software) was used to establish face and content validity. A 10 minute on-line version of the matrix was piloted across 11 MDTs. Each participant estimated where they thought the MDT performed for each indicator. Correlation and factor analyses examining convergent and discriminant validity were conducted using SPSS. Cronbach alpha was used to measure internal consistency and evaluate reliability. Ease of use and usefulness were also examined. Results: A total of 109 members completed the matrix, with representation from medical, nursing and allied health professionals. The mean results for each indicator are shown below (maximum 5). Overall results for the different teams varied from 1.2 to 4.2, with standard deviations ranging from 0.4 to 0.8. Conclusions: This matrix has the potential to be a simple, valid and reliable tool for MDTs to measure their performance and monitor improvement over time. The tool will now be refined and then disseminated to a wider audience for further validation and feedback. [Table: see text]

Clinical Safety Incident Taxonomy Performance on C4.5 Decision Tree and Random Forest

The paper applies an artificial intelligence centered method to classify 12 clinical safety incident (CSI) classes. The paper aims to establish a taxonomy that classifies the CSI reports into their correct classes automatically and with high accuracy. The study investigates feasibility of applying the C4.5 decision tree (DT) classifier and the random forest (RF) classifier for this purpose. The classifiers were trained using randomly selected 3600 CSIs from an Incident Information Management System (IIMS) used by seven hospitals. The taxonomies investigated were the Generic Reference Model (GRM) and the World Health Organization (WHO) patient safety classification. The classifiers trained 13 GRM CSI classes and 9 WHO CSI classes using a bag-of-words approach. The overall taxonomies performance on the RF classifier was better than on the DT classifier. The performance achieved by the classifier applying the WHO taxonomy was better than the GRM taxonomy. Four of the five poorly performing classes in the GRM taxonomy significantly improved their performance on changing the taxonomy. To improve the WHO taxonomy performance the improved WHO (WHO-I) taxonomy was built by adding a new class that did not exist in WHO but existed in GRM. The performance of the RF classifier applied to the WHO-I taxonomy further improved.

Rapid and Scalable Plant-Based Production of a Potent Plasmin Inhibitor Peptide

The backbone cyclic and disulfide bridged sunflower trypsin inhibitor-1 (SFTI-1) peptide is a proven effective scaffold for a range of peptide therapeutics. For production at laboratory scale, solid phase peptide synthesis techniques are widely used, but these synthetic approaches are costly and environmentally taxing at large scale. Here, we developed a plant-based approach for the recombinant production of SFTI-1-based peptide drugs. We show that transient expression in Nicotiana benthamiana allows for rapid peptide production, provided that asparaginyl endopeptidase enzymes with peptide-ligase functionality are co-expressed with the substrate peptide gene. Without co-expression, no target cyclic peptides are detected, reflecting rapid in planta degradation of non-cyclized substrate. We test this recombinant production system by expressing a SFTI-1-based therapeutic candidate that displays potent and selective inhibition of human plasmin. By using an innovative multi-unit peptide expression cassette, we show that in planta yields reach ~60 μg/g dry weight at 6 days post leaf infiltration. Using nuclear magnetic resonance structural analysis and functional in vitro assays, we demonstrate the equivalence of plant and synthetically derived plasmin inhibitor peptide. The methods and insights gained in this study provide opportunities for the large scale, cost effective production of SFTI-1-based therapeutics.

Patient-centric implementation of an electronic medication management system at a tertiary hospital in Western Sydney

BACKGROUND

Traditional implementations of electronic medication management (EMM) systems have involved two common formats - a 'big bang' approach on the day of go-live, or a phased ward-by-ward approach over months.

OBJECTIVE

To describe the patient-centric roll-out, a novel implementation model in converting from paper to EMM.

METHOD

This model iteratively converted a large tertiary teaching hospital to electronic from paper medication charts, commencing the roll-out in the emergency department (ED). The tenet of 'one patient, one chart' was maintained with new patients commenced on EMM, while existing inpatients were maintained on paper charts until their discharge. In the second week, all other intake points commenced patients on EMM, and in the third week, all remaining patients were manually converted to EMM. The implementation was assessed with training completion rates, staff satisfaction surveys, focus group interviews and incident logs.

RESULTS

At go-live, 79% of doctors, 68% of nurses and 90% of pharmacists were trained in the EMM system. The ED converted to electronic prescribing within 24 hours; by day 20, all patients were on EMM. Two hundred and thirty issues were logged, none critical, of which 22 were escalated. Of the 51,063 medications administered, there were 13 EMM-related clinical incidents including three double dosing errors, none of which led to an adverse event or death. Overall, 77% of staff surveyed were satisfied with the EMM implementation.

CONCLUSIONS

The patient-centric roll-out model represents an innovative and safe approach with a single medication chart reducing transcription and improved medication safety for the patient and the organisation.

A Configurational Analysis of Risk Patterns for Predicting the Outcome After Traumatic Brain Injury

Exploring relationships between admission variables and outcome using regression models has been the focus of Traumatic Brain Injury (TBI) research. Although practical and well established, these approaches do not evaluate interactions between predictors. We therefore applied a set-theoretic logical analysis to the Corticosteroid Randomization after Significant Head Injury (CRASH) trial database. Complete data analysis of 6945 patients demonstrated 9 different configurations of admission variables were sufficient for favorable outcome in 87.5% of all cases and explained 57% of favorable outcomes (moderate disability or good outcome). We also evaluated the contrasting configurations for unfavorable versus favorable outcome. Results are largely in line with findings of previous studies however the influence of age fell behind GCS components, which is unexpected. Specifying a combination of admission parameters that are likely to translate into a given clinical outcome is appealing from a clinician's perspective therefore our results have considerable translational value.

Evaluation of three rapid oral fluid test devices on the screening of multiple drugs of abuse including ketamine

Rapid oral fluid testing (ROFT) devices have been extensively evaluated for their ability to detect common drugs of abuse; however, the performance of such devices on simultaneous screening for ketamine has been scarcely investigated. The present study evaluated three ROFT devices (DrugWipe^® 6S, Ora-Check^® and SalivaScreen^®) on the detection of ketamine, opiates, methamphetamine, cannabis, cocaine and MDMA. A liquid chromatography tandem mass spectrometry (LCMS) assay was firstly established and validated for confirmation analysis of the six types of drugs and/or their metabolites. In the field test, the three ROFT devices were tested on subjects recruited from substance abuse clinics/rehabilitation centre. Oral fluid was also collected using Quantisal^® for confirmation analysis. A total of 549 samples were collected in the study. LCMS analysis on 491 samples revealed the following drugs: codeine (55%), morphine (49%), heroin (40%), methamphetamine (35%), THC (8%), ketamine (4%) and cocaine (2%). No MDMA-positive cases were observed. Results showed that the overall specificity and accuracy were satisfactory and met the DRUID standard of >80% for all 3 devices. Ora-Check^® had poor sensitivities (ketamine 36%, methamphetamine 63%, opiates 53%, cocaine 60%, THC 0%). DrugWipe^® 6S showed good sensitivities in the methamphetamine (83%) and opiates (93%) tests but performed relatively poorly for ketamine (41%), cocaine (43%) and THC (22%). SalivaScreen^® also demonstrated good sensitivities in the methamphetamine (83%) and opiates (100%) tests, and had the highest sensitivity for ketamine (76%) and cocaine (71%); however, it failed to detect any of the 28 THC-positive cases. The test completion rate (proportion of tests completed with quality control passed) were: 52% (Ora-Check^®), 78% (SalivaScreen^®) and 99% (DrugWipe^® 6S).

Co-expression of a cyclizing asparaginyl endopeptidase enables efficient production of cyclic peptides in planta

Cyclotides are ultra-stable, backbone-cyclized plant defence peptides that have attracted considerable interest in the pharmaceutical industry. This is due to their range of native bioactivities as well as their ability to stabilize other bioactive peptides within their framework. However, a hindrance to their widespread application is the lack of scalable, cost-effective production strategies. Plant-based production is an attractive, benign option since all biosynthetic steps are performed in planta. Nonetheless, cyclization in non-cyclotide-producing plants is poor. Here, we show that cyclic peptides can be produced efficiently in Nicotiana benthamiana, one of the leading plant-based protein production platforms, by co-expressing cyclotide precursors with asparaginyl endopeptidases that catalyse peptide backbone cyclization. This approach was successful in a range of other plants (tobacco, bush bean, lettuce, and canola), either transiently or stably expressed, and was applicable to both native and engineered cyclic peptides. We also describe the use of the transgenic system to rapidly identify new asparaginyl endopeptidase cyclases and interrogate their substrate sequence requirements. Our results pave the way for exploiting cyclotides for pest protection in transgenic crops as well as large-scale production of cyclic peptide pharmaceuticals in plants.

Tribes and tribulations: interdisciplinary eHealth in providing services for people with a traumatic brain injury (TBI)

Background

eHealth has potential for supporting interdisciplinary care in contemporary traumatic brain injury (TBI) rehabilitation practice, yet little is known about whether this potential is being realised, or what needs to be done to further support its implementation. The purpose of this study was to explore health professionals’ experiences of, and attitudes towards eHealth technologies to support interdisciplinary practice within rehabilitation for people after TBI.

Methods

A qualitative study using narrative analysis was conducted. One individual interview and three focus groups were conducted with health professionals (n = 17) working in TBI rehabilitation in public and private healthcare settings across regional and metropolitan New South Wales, Australia.

Results

Narrative analysis revealed that participants held largely favourable views about eHealth and its potential to support interdisciplinary practice in TBI rehabilitation. However, participants encountered various issues related to (a) the design of, and access to electronic medical records, (b) technology, (c) eHealth implementation, and (d) information and communication technology processes that disconnected them from the work they needed to accomplish. In response, health professionals attempted to make the most of unsatisfactory eHealth systems and processes, but were still mostly unsuccessful in optimising the quality, efficiency, and client-centredness of their work.

Conclusions

Attention to sources of disconnection experienced by health professionals, specifically design of, and access to electronic health records, eHealth resourcing, and policies and procedures related to eHealth and interdisciplinary practice are required if the potential of eHealth for supporting interdisciplinary practice is to be realised.

Field resistance to Fusarium oxysporum and Verticillium dahliae in transgenic cotton expressing the plant defensin NaD1

The plant defensin NaD1, from Nicotiana alata, has potent antifungal activity against a range of filamentous fungi including the two important cotton pathogens, Fusarium oxysporum f. sp. vasinfectum (Fov) and Verticillium dahliae. Transgenic cotton plants expressing NaD1 were produced and plants from three events were selected for further characterization. Homozygous plants were assessed in greenhouse bioassays for resistance to Fov. One line (D1) was selected for field trial testing over three growing seasons in soils naturally infested with Fov and over two seasons in soils naturally infested with V. dahliae. In the field trials with Fov-infested soil, line D1 had 2-3-times the survival rate, a higher tolerance to Fov (higher disease rank), and a 2-4-fold increase in lint yield compared to the non-transgenic Coker control. When transgenic line D1 was planted in V. dahliae-infested soil, plants had a higher tolerance to Verticillium wilt and up to a 2-fold increase in lint yield compared to the non-transgenic Coker control. Line D1 did not exhibit any detrimental agronomic features compared to the parent Coker control when plants were grown in non-diseased soil. This study demonstrated that the expression of NaD1 in transgenic cotton plants can provide substantial resistance to two economically important fungal pathogens.

The C-terminal propeptide of a plant defensin confers cytoprotective and subcellular targeting functions

BACKGROUND

Plant defensins are small (45-54 amino acids), basic, cysteine-rich proteins that have a major role in innate immunity in plants. Many defensins are potent antifungal molecules and are being evaluated for their potential to create crop plants with sustainable disease resistance. Defensins are produced as precursor molecules which are directed into the secretory pathway and are divided into two classes based on the absence (class I) or presence (class II) of an acidic C-terminal propeptide (CTPP) of about 33 amino acids. The function of this CTPP had not been defined.

RESULTS

By transgenically expressing the class II plant defensin NaD1 with and without its cognate CTPP we have demonstrated that NaD1 is phytotoxic to cotton plants when expressed without its CTPP. Transgenic cotton plants expressing constructs encoding the NaD1 precursor with the CTPP had the same morphology as non-transgenic plants but expression of NaD1 without the CTPP led to plants that were stunted, had crinkled leaves and were less viable. Immunofluorescence microscopy and transient expression of a green fluorescent protein (GFP)-CTPP chimera were used to confirm that the CTPP is sufficient for vacuolar targeting. Finally circular dichroism and NMR spectroscopy were used to show that the CTPP adopts a helical confirmation.

CONCLUSIONS

In this report we have described the role of the CTPP on NaD1, a class II defensin from Nicotiana alata flowers. The CTPP of NaD1 is sufficient for vacuolar targeting and plays an important role in detoxification of the defensin as it moves through the plant secretory pathway. This work may have important implications for the use of defensins for disease protection in transgenic crops.

A chimeric arabinogalactan protein promotes somatic embryogenesis in cotton cell culture

Arabinogalactan proteins (AGPs) are a family of extracellular plant proteoglycans implicated in many aspects of plant growth and development, including in vitro somatic embryogenesis (SE). We found that specific AGPs were produced by cotton (Gossypium hirsutum) calli undergoing SE and that when these AGPs were isolated and incorporated into tissue culture medium, cotton SE was promoted. When the AGPs were partly or fully deglycosylated, SE-promoting activity was not diminished. Testing of AGPs separated by reverse-phase high-performance liquid chromatography revealed that the SE-promoting activity resided in a hydrophobic fraction. We cloned a full-length complementary DNA (cotton PHYTOCYANIN-LIKE ARABINOGALACTAN-PROTEIN1 [GhPLA1]) that encoded the protein backbone of an AGP in the active fraction. It has a chimeric structure comprising an amino-terminal signal sequence, a phytocyanin-like domain, an AGP-like domain, and a hydrophobic carboxyl-terminal domain. Recombinant production of GhPLA1 in tobacco (Nicotiana tabacum) cells enabled us to purify and analyze a single glycosylated AGP and to demonstrate that this chimeric AGP promotes cotton SE. Furthermore, the nonglycosylated phytocyanin-like domain from GhPLA1, which was bacterially produced, also promoted SE, indicating that the glycosylated AGP domain was unnecessary for in vitro activity.

Effects of Uptake and Efflux Transporter Inhibition on Erythromycin Breath Test Results

The erythromycin breath test (EBT) is a standard test used to evaluate the extent of CYP3A4 activity. This study examines whether presumed changes in CYP3A4 activity are in fact related to inhibition of an uptake organic anion transporter using rifampin and inhibition of the efflux hepatic P-glycoprotein transporter using lansoprazole. Three EBT tests in healthy adults were conducted: EBT alone, with lansoprazole, and with rifampin. For all subjects, lansoprazole treatment increased respiratory (14)C excretion by +0.25+/-0.51 met/h (P=0.07) and rifampin decreased (14)C excretion by -0.44+/-0.40 met/h (P<0.001) compared with baseline. Comparing lansoprazole to rifampin, (14)C excretion increased by +0.69+/-0.50 met/h (P<0.001). Only women had significant changes after drug infusion: (14)C excretion after rifampin -0.40+/-0.36 met/h (P=0.018) and +0.47+/-0.44 met/h (P=0.018) after lansoprazole. Relying on EBT without considering transporter interactions can lead to errors in interpreting the degree of CYP3A4 metabolism.

In vivo and in vitro examination of the functional significances of novel lamin gene mutations in heart failure patients

CONTEXT

Lamin A/C (LMNA) gene variations have been reported in more than one third of genotyped families with dilated cardiomyopathy (DCM). However, the relationship between LMNA mutation and the development of DCM is poorly understood.

METHODS AND RESULTS

We found that end stage DCM patients carrying LMNA mutations displayed either dramatic ultrastructural changes of the cardiomyocyte nucleus (D192G) or nonspecific changes (R541S). Overexpression of the D192G lamin C dramatically increased the size of intranuclear speckles and reduced their number. This phenotype was only partially reversed by coexpression of the D192G and wild type lamin C. Moreover, the D192G mutation precludes insertion of lamin C into the nuclear envelope when co-transfected with the D192G lamin A. By contrast, the R541S phenotype was entirely reversed by coexpression of the R541S and wild type lamin C. As lamin speckle size is known to be correlated with regulation of transcription, we assessed the SUMO1 distribution pattern in the presence of mutated lamin C and showed that D192G lamin C expression totally disrupts the SUMO1 pattern.

CONCLUSION

Our in vivo and in vitro results question the relationship of causality between LMNA mutations and the development of heart failure in some DCM patients and therefore, the reliability of genetic counselling. However, LMNA mutations producing speckles result not only in nuclear envelope structural damage, but may also lead to the dysregulation of cellular functions controlled by sumoylation, such as transcription, chromosome organisation, and nuclear trafficking.

Influence of alpha-helices on the emulsifying properties of proteins

A peptide derived from apomyoglobin by cyanogen bromide cleavage was found to be an active emulsifier. This molecule, peptide 1-55, has two potential amphipathic alpha-helices and a hydrophilic C-terminal domain. The importance of each of these domains to the emulsifying properties of this molecule was investigated by testing the products of gene constructs based on the sequence of peptide 1-55, but lacking one of the three domains. The emulsifying activity of the peptides lacking either of the alpha-helices was correlated with the hydrophobic moments of their respective helices. The hydrophobic moment is a measure of the amphipathicity of alpha-helices; a hydrophobic moment analysis of other emulsifying peptides supports the hypothesis that a high hydrophobic moment contributes to good emulsifying properties in a molecule which contains alpha-helices.

Effect of denaturants on the emulsifying activity of proteins

The relationship between protein flexibility and emulsifying activity was investigated by disrupting disulfide bonds and/or noncovalent interactions of the protein. Oil-in-water emulsions using model proteins (apomyoglobin, beta-casein, alpha-casein, lysozyme, bovine serum albumin, kappa-casein, and beta-lactoglobulin) were made in the presence of chemical denaturants (dithiothreitol and/or urea). In most cases, the presence of denaturants enhanced emulsifying activity. The effect was protein-specific and depended on the relative importance of disulfide bonds and noncovalent interactions in stabilizing the native conformation of each protein. Implications for the design of novel protein emulsifiers are discussed.

Clusterin is an ATP-independent chaperone with very broad substrate specificity that stabilizes stressed proteins in a folding-competent state

We recently reported that the ubiquitous, secreted protein clusterin has chaperone activity in vitro [Humphreys et al. (1999) J. Biol. Chem. 274, 6875-6881]. In this study, we demonstrate that clusterin (i) inhibits stress-induced precipitation of a very broad range of structurally divergent protein substrates, (ii) binds irreversibly via an ATP-independent mechanism to stressed proteins to form solubilized high molecular weight complexes, (iii) lacks detectable ATPase activity, (iv) when acting alone, does not effect refolding of stressed proteins in vitro, and (v) stabilizes stressed proteins in a state competent for refolding by heat shock protein 70 (HSP70). Furthermore, we show that, at physiological levels, clusterin inhibits stress-induced precipitation of proteins in undiluted human serum. Clusterin represents the first identified secreted mammalian chaperone. However, reports from others suggest that, at least under stress conditions, clusterin may be retained within cells to exert a protective effect. Regardless of the topological site(s) of action, the demonstration that clusterin can stabilize stressed proteins in a refolding-competent state suggests that, during stresses, the action of clusterin may inhibit rapid and irreversible protein precipitation and produce a reservoir of inactive but stabilized molecules from which other refolding chaperones can subsequently salvage functional proteins.

Effect of premedication guidelines and leukoreduction on the rate of febrile nonhaemolytic platelet transfusion reactions

Platelet transfusion reactions were prospectively studied in haematology/oncology patients at five university teaching hospitals over three consecutive summers. The initial summer study provided baseline information on the use of premedications and the rate of platelet transfusion reactions (fever, chills, rigors and hives). Most (73%) platelet recipients were premedicated and 30% (95% CI 28-33%) of transfusions were complicated by reactions. The second study followed implementation of guidelines for premedicating platelet transfusions. Despite a marked reduction in premedication (50%), there was little change in the platelet transfusion reaction rate, 26% (95% CI 24-29%), or the type of reactions. The third study followed implementation of prestorage platelet leukoreduction while maintaining the premedication guidelines. The reaction rate decreased to 19% (95% CI 17-22%). For nonleukoreduced platelets, there was a statistically significant association between the platelet age and reaction rate (P = 0.04). For leukoreduced platelets, there was no statistically significant association between platelet age and reaction rate (P = 0.5). Plasma reduction of nonleukoreduced platelet products also reduced the reaction rate. These prospective studies document a high rate of platelet transfusion reactions in haematology/oncology patients and indicate premedication use can be reduced without increasing the reaction rate. Prestorage leukoreduction and/or plasma reduction of platelet products reduces but does not eliminate febrile nonhemolytic platelet transfusion reactions.

Alternatively spliced isoforms of the rat eye sodium/calcium+potassium exchanger NCKX1

We have investigated the structure, function, and expression of the rat eye sodium/calcium+potassium exchanger NCKX1. The sequence of independent rat NCKX1 clones and the analysis of rat eye mRNA by RT-PCR revealed a region of alternative splicing that comprised four exons and encoded a stretch of 113 amino acids near the beginning of the large cytosolic loop. In comparison with other NCKX1 molecules and the rat NCKX2 protein, rat NCKX1 was highly conserved within the hydrophobic regions but was quite divergent in the two large hydrophilic loops. The only exception was the region of the cytosolic loop encoded by the second alternatively spliced exon, which was approximately 60% identical. Similar to bovine, but different from human, rat NCKX1 possessed an acidic motif that was repeated 14 times in the cytoplasmic loop. Analysis of NCKX1 expression in different rat tissues by Northern blot revealed a very high level of expression of a 7-kb transcript in the eye but also lower levels of transcripts of various lengths in other tissues. The recombinant rat NCKX1 protein was tagged in the extracellular loop with the FLAG epitope and expressed in HEK-293 cells. Surface delivery and potassium-dependent sodium/calcium exchange activity were observed for each spliced variant.

Ultrastructure and function of the fractalkine mucin domain in CX(3)C chemokine domain presentation

Fractalkine (FKN), a CX(3)C chemokine/mucin hybrid molecule on endothelium, functions as an adhesion molecule to capture and induce firm adhesion of a subset of leukocytes in a selectin- and integrin-independent manner. We hypothesized that the FKN mucin domain may be important for its function in adhesion, and tested the ability of secreted alkaline phosphatase (SEAP) fusion proteins containing the entire extracellular region (FKN-SEAP), the chemokine domain (CX3C-SEAP), or the mucin domain (mucin-SEAP) to support firm adhesion under flow. CX3C-SEAP induced suboptimal firm adhesion of resting peripheral blood mononuclear cells, compared with FKN-SEAP, and mucin-SEAP induced no firm adhesion. CX3C-SEAP and FKN-SEAP bound to CX(3)CR1 with similar affinities. By electron microscopy, fractalkine was 29 nm in length with a long stalk (mucin domain), and a globular head (CX(3)C). To test the function of the mucin domain, a chimeric protein replacing the mucin domain with a rod-like segment of E-selectin was constructed. This chimeric protein gave the same adhesion of peripheral blood mononuclear cells as intact FKN, both when immobilized on glass and when expressed on the cell surface. This implies that the function of the mucin domain is to provide a stalk, extending the chemokine domain away from the endothelial cell surface to present it to flowing leukocytes.

Structure-Function Analysis of the Emulsifying and Interfacial Properties of Apomyoglobin and Derived Peptides

Apomyoglobin was chosen as a model to study the emulsifying properties of proteins. It was cleaved into three peptides using cyanogen bromide and these peptides were purified and tested for emulsifying and interfacial properties. Two of the peptides had improved emulsifying activity compared to the whole protein. The peptide (residues 1-55) with the highest emulsifying activity and whole apomyoglobin were studied further. The amount of protein or peptide adsorbed at the oil-water interface of an emulsion was measured and the surface area occupied per molecule was calculated. For apomyoglobin, at maximal surface coverage each molecule occupied a surface area of approximately 8 nm2. This is consistent with a packed monolayer, based on the approximate dimensions of apomyoglobin. For peptide (1-55), at maximal surface coverage each molecule occupied a surface area of approximately 3 nm2. This is consistent with the area that the two amphipathic alpha-helices which are potentially present in this molecule would cover, if they were aligned along the oil-water interface. The different structural characteristics of these molecules responsible for their emulsifying properties are discussed. Copyright 1999 Academic Press.