Native metabolomics identifies the rivulariapeptolide family of protease inhibitors.

The identity and biological activity of most metabolites still remain unknown. A bottleneck in the exploration of metabolite structures and pharmaceutical activities is the compound purification needed for bioactivity assignments and downstream structure elucidation. To enable bioactivity-focused compound identification from complex mixtures, we develop a scalable native metabolomics approach that integrates non-targeted liquid chromatography tandem mass spectrometry and detection of protein binding via native mass spectrometry. A native metabolomics screen for protease inhibitors from an environmental cyanobacteria community reveals 30 chymotrypsin-binding cyclodepsipeptides. Guided by the native metabolomics results, we select and purify five of these compounds for full structure elucidation via tandem mass spectrometry, chemical derivatization, and nuclear magnetic resonance spectroscopy as well as evaluation of their biological activities. These results identify rivulariapeptolides as a family of serine protease inhibitors with nanomolar potency, highlighting native metabolomics as a promising approach for drug discovery, chemical ecology, and chemical biology studies.

RNase P Inhibitors Identified as Aggregators.

RNase P is an essential enzyme responsible for tRNA 5'-end maturation. In most bacteria, the enzyme is a ribonucleoprotein consisting of a catalytic RNA subunit and a small protein cofactor termed RnpA. Several studies have reported small-molecule inhibitors directed against bacterial RNase P that were identified by high-throughput screenings. Using the bacterial RNase P enzymes from Thermotoga maritima, Bacillus subtilis, and Staphylococcus aureus as model systems, we found that such compounds, including RNPA2000 (and its derivatives), iriginol hexaacetate, and purpurin, induce the formation of insoluble aggregates of RnpA rather than acting as specific inhibitors. In the case of RNPA2000, aggregation was induced by Mg2+ ions. These findings were deduced from solubility analyses by microscopy and high-performance liquid chromatography (HPLC), RnpA-inhibitor co-pulldown experiments, detergent addition, and RnpA titrations in enzyme activity assays. Finally, we used a B. subtilis RNase P depletion strain, whose lethal phenotype could be rescued by a protein-only RNase P of plant origin, for inhibition zone analyses on agar plates. These cell-based experiments argued against RNase P-specific inhibition of bacterial growth by RNPA2000. We were also unable to confirm the previously reported nonspecific RNase activity of S. aureus RnpA itself. Our results indicate that high-throughput screenings searching for bacterial RNase P inhibitors are prone to the identification of "false positives" that are also termed pan-assay interference compounds (PAINS).

Survival of hendra virus in the environment: modelling the effect of temperature.

Hendra virus (HeV), a highly pathogenic zoonotic paramyxovirus recently emerged from bats, is a major concern to the horse industry in Australia. Previous research has shown that higher temperatures led to lower virus survival rates in the laboratory. We develop a model of survival of HeV in the environment as influenced by temperature. We used 20 years of daily temperature at six locations spanning the geographic range of reported HeV incidents to simulate the temporal and spatial impacts of temperature on HeV survival. At any location, simulated virus survival was greater in winter than in summer, and in any month of the year, survival was higher in higher latitudes. At any location, year-to-year variation in virus survival 24 h post-excretion was substantial and was as large as the difference between locations. Survival was higher in microhabitats with lower than ambient temperature, and when environmental exposure was shorter. The within-year pattern of virus survival mirrored the cumulative within-year occurrence of reported HeV cases, although there were no overall differences in survival in HeV case years and non-case years. The model examines the effect of temperature in isolation; actual virus survivability will reflect the effect of additional environmental factors.

Sustainable management for rangelands in a variable climate: evidence and insights from northern Australia.

Inter-annual rainfall variability is a major challenge to sustainable and productive grazing management on rangelands. In Australia, rainfall variability is particularly pronounced and failure to manage appropriately leads to major economic loss and environmental degradation. Recommended strategies to manage sustainably include stocking at long-term carrying capacity (LTCC) or varying stock numbers with forage availability. These strategies are conceptually simple but difficult to implement, given the scale and spatial heterogeneity of grazing properties and the uncertainty of the climate. This paper presents learnings and insights from northern Australia gained from research and modelling on managing for rainfall variability. A method to objectively estimate LTCC in large, heterogeneous paddocks is discussed, and guidelines and tools to tactically adjust stocking rates are presented. The possible use of seasonal climate forecasts (SCF) in management is also considered. Results from a 13-year grazing trial in Queensland show that constant stocking at LTCC was far more profitable and largely maintained land condition compared with heavy stocking (HSR). Variable stocking (VAR) with or without the use of SCF was marginally more profitable, but income variability was greater and land condition poorer than constant stocking at LTCC. Two commercial scale trials in the Northern Territory with breeder cows highlighted the practical difficulties of variable stocking and provided evidence that heavier pasture utilisation rates depress reproductive performance. Simulation modelling across a range of regions in northern Australia also showed a decline in resource condition and profitability under heavy stocking rates. Modelling further suggested that the relative value of variable v. constant stocking depends on stocking rate and land condition. Importantly, variable stocking may possibly allow slightly higher stocking rates without pasture degradation. Enterprise-level simulations run for breeder herds nevertheless show that poor economic performance can occur under constant stocking and even under variable stocking in some circumstances. Modelling and research results both suggest that a form of constrained flexible stocking should be applied to manage for climate variability. Active adaptive management and research will be required as future climate changes make managing for rainfall variability increasingly challenging.

Sexual selection uncouples the evolution of brain and body size in pinnipeds.

The size of the vertebrate brain is shaped by a variety of selective forces. Although larger brains (correcting for body size) are thought to confer fitness advantages, energetic limitations of this costly organ may lead to trade-offs, for example as recently suggested between sexual traits and neural tissue. Here, we examine the patterns of selection on male and female brain size in pinnipeds, a group where the strength of sexual selection differs markedly among species and between the sexes. Relative brain size was negatively associated with the intensity of sexual selection in males but not females. However, analyses of the rates of body and brain size evolution showed that this apparent trade-off between sexual selection and brain mass is driven by selection for increasing body mass rather than by an actual reduction in male brain size. Our results suggest that sexual selection has important effects on the allometric relationships of neural development.

Foot care education in patients with diabetes at low risk of complications: a consensus statement.

AIMS: To define and agree a practical educational framework for delivery by all healthcare professionals managing patients with diabetes, particularly those at low risk of developing foot complications. METHODS: A consensus meeting of a multidisciplinary expert panel. Prior to the meeting, relevant clinical papers were disseminated to the panel for review. The consensus was largely based upon the experts' clinical experience and judgement. RESULTS: Four main health behaviours were identified for those at low risk of developing foot complications, namely: control of blood glucose levels; attendance at annual foot screening examination; reporting of any changes in foot health immediately; and the engagement in a simple daily foot care routine. CONCLUSION: There is currently little evidence-based literature to support specific foot care practices. Patients with diabetes at low risk of developing complications should be encouraged to undertake a basic foot care regimen to reduce their likelihood of developing complications.

Design search and optimization in aerospace engineering.

In this paper, we take a design-led perspective on the use of computational tools in the aerospace sector. We briefly review the current state-of-the-art in design search and optimization (DSO) as applied to problems from aerospace engineering, focusing on those problems that make heavy use of computational fluid dynamics (CFD). This ranges over issues of representation, optimization problem formulation and computational modelling. We then follow this with a multi-objective, multi-disciplinary example of DSO applied to civil aircraft wing design, an area where this kind of approach is becoming essential for companies to maintain their competitive edge. Our example considers the structure and weight of a transonic civil transport wing, its aerodynamic performance at cruise speed and its manufacturing costs. The goals are low drag and cost while holding weight and structural performance at acceptable levels. The constraints and performance metrics are modelled by a linked series of analysis codes, the most expensive of which is a CFD analysis of the aerodynamics using an Euler code with coupled boundary layer model. Structural strength and weight are assessed using semi-empirical schemes based on typical airframe company practice. Costing is carried out using a newly developed generative approach based on a hierarchical decomposition of the key structural elements of a typical machined and bolted wing-box assembly. To carry out the DSO process in the face of multiple competing goals, a recently developed multi-objective probability of improvement formulation is invoked along with stochastic process response surface models (Krigs). This approach both mitigates the significant run times involved in CFD computation and also provides an elegant way of balancing competing goals while still allowing the deployment of the whole range of single objective optimizers commonly available to design teams.

Developing alternative devices to the long-term urinary catheter for draining urine from the bladder.

The self-retaining urinary catheter is used for long-term drainage of urine from the bladder only as a last resort because of serious associated complications, yet it remains a routine method for managing older and disabled patients with loss of bladder control. Blockage of the catheter from calcified deposits within its lumen is a common occurrence, obstructing the passage of urine and causing an urgent, unpredictable problem for patients, carers and the nursing staff. The need for further research on the subject has been recognized for many years. The SuPort Project aimed to develop an alternative suprapubic urine collection system. This report outlines the approach adopted towards the design and selection of the novel device, the production problems that ensued and the small clinical trial of a modified prototype.

Antidepressant prescribing in nursing homes: is there a place for tricyclics?

OBJECTIVE: To deduce a model describing physicians' choice of antidepressants for treating elderly nursing home patients. METHODS: Subjects were geriatric residents of 137 skilled nursing facilities who regularly received an antidepressant medication for at least one month (n = 3,440, 28% of all residents). Reasons for prescribing antidepressants and physicians' diagnoses of depression and dementia were identified by medical record audit. Residents were grouped by dementia and antidepressant target symptoms (depression, or one or more non-psychiatric symptoms, i.e. insomnia, pain, incontinence, itching). RESULTS: Selective serotonin reuptake inhibitors (SSRIs) were prescribed preferentially over tricyclic antidepressants (TCAs) for treating depression in both demented and non-demented residents, but TCAs were nine times more likely to be prescribed for treating non-psychiatric target symptoms alone. When non-psychiatric target symptoms were present without depression or dementia, both amitriptyline and nortriptyline prescribing was increased, but amitriptyline appeared to be the antidepressant of choice. In all subgroups examined, its use was two to five times more prevalent when such symptoms were present. In patients with dementia, amitriptyline prescribing declined whether or not non-psychiatric target symptoms were present, but nortriptyline prescribing did not; nortriptyline was three times more likely than amitriptyline to be prescribed in the presence of dementia. CONCLUSIONS: Physicians prescribe anticholinergic TCAs principally to treat common non-depressive symptoms in nursing home residents, preferring SSRIs for uncomplicated depression and depression with dementia. They tend to avoid prescribing anticholinergic TCAs other than nortriptyline when they recognize a patient as demented. The data suggest that physicians employ a decision model for antidepressant prescribing that simultaneously recognizes the utility of TCAs in treating non-psychiatric symptoms and the anticholinergic vulnerability of older, especially demented, patients. Whether or not this model leads to optimal patient management requires further study.

Urinary catheter 'deflation cuff' formation: clinical audit and quantitative in vitro analysis.

OBJECTIVE: To investigate reports from district nursing staff of difficulty in removing long-term urinary catheters (LTCs) because of the formation of a 'cuff' on deflating the self-retaining balloon. PATIENTS AND METHODS: Problems experienced by district nurses when removing urethral and suprapubic LTCs were audited, noting the type of problem, the catheter and any action taken. Quantitative in vitro studies were conducted on the deflated self-retaining balloons after incubating a similar range of catheters in saline at 37 degrees C for 6 weeks, using suprapubic profilometry to assess the resistance to withdrawal (retention force). RESULTS: Questionnaires were returned on 154 patients with LTCs; 56% had urethral and 44% suprapubic catheters. The catheters were hydrogel-coated (83%), all-silicone (13%) and PTFE-coated (3%). Twenty-two (14%) of the sample reported problems with catheter removal in the previous year, including 15 (68%) with all-silicone catheters and 15 (68%) with suprapubic catheters; cuff formation was noted in 60%. In the laboratory, 10 of the balloons formed a 'cuff' on deflation, but there was great variability in the effect this had on the retention force, with values of 0.5-3 N for different catheters. CONCLUSIONS: Most problems with catheter removal involved all-silicone and suprapubic catheters. Suprapubic profilometry confirmed increased resistance to withdrawal by formation of a 'cuff' on deflation of the balloon of all-silicone catheters. These results suggest that the first choice of catheter material for long-term urethral and suprapubic use should be hydrogel-coated latex.

The dynamics of grazed woodlands in southwest Queensland, Australia and their effect on greenhouse gas emissions.

This study outlines the development of an approach to evaluate the sources, sinks, and magnitudes of greenhouse gas emissions from a grazed semiarid rangeland dominated by mulga (Acacia aneura) and how these emissions may be altered by changes in management. This paper describes the modification of an existing pasture production model (GRASP) to include a gas emission component and a dynamic tree growth and population model. An exploratory study was completed to investigate the likely impact of changes in burning practices and stock management on emissions. This study indicates that there is a fundamental conflict between maintaining agricultural productivity and reducing greenhouse gas emissions on a given unit of land. Greater agricultural productivity is allied with the system being an emissions source while production declines and the system becomes a net emissions sink as mulga density increases. Effective management for sheep production results in the system acting as a net source (approximately 60-200 kg CO2 equivalents/ha/year). The magnitude of the source depends on the management strategies used to maintain the productivity of the system and is largely determined by starting density and average density of the mulga over the simulation period. Prior to European settlement, it is believed that the mulga lands were burnt almost annually. Simulations indicate that such a management approach results in the system acting as a small net sink with an average net absorption of greenhouse gases of 14 kg CO2 equivalents/ha/year through minimal growth of mulga stands. In contrast, the suppression of fire and the introduction of grazing results in thickening of mulga stands and the system can act as a significant net sink absorbing an average of 1000 kg CO2 equivalents/ha/year. Although dense mulga will render the land largely useless for grazing, land in this region is relatively inexpensive and could possibly be developed as a cost-effective carbon offset for greenhouse gas emissions elsewhere. These results also provide support for the hypothesis that changes in land management, and particularly, suppression of fire is chiefly responsible for the observed increases in mulga density over the past century.

Are the salutogenic effects of social supports modified by income? A test of an "added value hypothesis".

Older adults (54 men, 113 women; M age = 69.5 years) were examined to test the hypothesis that social supports would be more salutogenic (health promoting) for persons with lower incomes than for persons with higher incomes. Interactions of income and social supports (mean of 3 emotional scales of the Interpersonal Support Evaluation List) at study entry predicted changes 15-18 months later in a cardiovascular composite (linear combination of high-density lipoproteins-mean arterial pressure; p < .05), and natural killer cell activity (p < .05). For both outcomes, emotional supports were salutogenic for persons with lower incomes (< or =$29,000/year), but not for persons with higher incomes (>$29,000/year). In contrast, interactions of the Tangible Support Scale with income did not occur. Persons with lower incomes may derive benefits from social supports that go beyond tangible assistance.

Urinary free cortisol and sleep under baseline and stressed conditions in healthy senior women: effects of estrogen replacement therapy.

The purpose of this study was to examine the effects of a mild 24-h stress (indwelling IV catheter) on cortisol and sleep in postmenopausal women, and to evaluate differences due to estrogen replacement therapy (ERT) status. This study, conducted in the General Clinical Research Center at the University of Washington Medical Center, examined sleep, cortisol and sleep-cortisol relationships in both baseline and stress conditions, and compared women on ERT with women not on ERT. Forty-two women (age=69.6 +/- 6.2 years [SD]), of whom 20 were on ERT, participated. Urinary free cortisol (UFC) levels and sleep polysomnography were measured over both 24-baseline and stress condition. Sleep was impaired in the stress condition for both groups; mean UFC levels were higher, sleep efficiency and minutes of stages 2, 3 and 4 sleep were reduced, and morning risetime was earlier in the stress than baseline condition. For the combined groups, age-controlled correlations between 24-h UFC and sleep were significant in both conditions: at baseline, UFC levels were associated with earlier time of rising and less REM sleep, and under stress with reduced sleep efficiency, there was reduced minutes of stages 2, 3, 4 sleep, reduced REM sleep, and an earlier risetime. The pattern of negative significant correlations between UFC and sleep/sleep timing remained when plasma estrogen was statistically controlled; however, when groups were examined separately, the significant negative UFC-sleep relationships were confined to the non ERT group. Elevated 24-h UFC is associated with impaired sleep and earlier awakening in older women not on ERT, but not in women on ERT.

Sense of coherence buffers relationships of chronic stress with fasting glucose levels.

Sense of coherence (SOC) was examined as a buffer of the relationship of chronic stress with fasting glucose and insulin levels. Spouse caregivers of persons with diagnoses of Alzheimer's disease (AD) (n = 73) were compared to controls [spouses of nondemented persons (n = 69)], group-matched on age/gender. After controlling for anger and coronary heart disease (CHD), interactions of SOC and gender explained variance in glucose (but not insulin) at study entry (T1) and 15-18 months later (T2). However, this occurred only in caregivers. At both times SOC and glucose were negatively related in men caregivers but not in women caregivers or in controls. In caregivers (but not controls), SOC at T1 predicted glucose at T2, independent of gender, anger, and glucose at T1; and hassles at T1 appeared to mediate this relationship. Future research should examine SOC as a buffer of other chronic stressors and metabolic variables.

The Mini-Cog: receiver operating characteristics with expert and naïve raters.

BACKGROUND: As elderly populations grow, dementia detection in the community is increasingly needed. Existing screens are largely unused because of time and training requirements. We developed the Mini-Cog, a brief dementia screen with high sensitivity, specificity, and acceptability. Here we describe the development of its scoring algorithm, its receiver operating characteristics (ROC), and the generalizability of its clock drawing scoring system. SAMPLE AND METHODS: A total of 249 multi-lingual older adults were examined. Scores on the three-item recall task and the clock drawing task (CDT-CERAD version) were combined to create an optimal algorithm. Receiver operating characteristics for seven alternatives were compared with those of the MMSE and the CASI using expert raters. To assess the CDT scoring generalizability, 20 naïve raters, without explicit instructions or prior CDT exposure, scored 80 randomly selected clocks as "normal" or "abnormal" (20 from each of four CERAD categories). RESULTS: An algorithm maximizing sensitivity and correct diagnosis was defined. Its ROC compared favorably with those of the MMSE and CASI. CDT concordance between naïve and trained raters was >98% for normal, moderately and severely impaired clocks, but lower (60%) for mildly impaired clocks. Recalculation of the Mini-Cog's performance, assuming that naïve raters would score all mildly impaired CDTs in the full sample as normal, retained high sensitivity (97%) and specificity (95%). CONCLUSION: The Mini-Cog algorithm performs well with simple clock scoring techniques. The results suggest that the Mini-Cog may be used successfully by relatively untrained raters as a first-stage dementia screen. Further research is needed to characterize the Mini-Cog's utility when population dementia prevalences are low.

Learning clinical teaching. Is it magic?

Clinical teaching in nursing is a complex phenomenon that lacks a coherent theoretical base and is perplexing to novices, who tend to teach as they were taught. Nursing educators must find strategies to assist novice clinical teachers to learn the practice of clinical teaching. This article reports on the findings of a qualitative study that describes the process of learning clinical teaching through the voices of five novice and five expert clinical teachers. Essential differences between novices and experts are presented, and the challenges of preparing clinical teachers are discussed.

Dealing with the unsafe student in clinical practice.

How do social justice issues affect the clinical evaluation of students? An emotionally charged issue, clinical evaluation can become a mine field when it becomes entangled with issues of social justice. The authors discuss the issues of justice and fairness in relation to situations that arise when a student repeatedly fails to meet minimum expectations for clinical performance. They discuss policies developed to deal with such situations and describe the application of these policies in a case study.