Bimekizumab treatment in patients with active axial spondyloarthritis: 52-week efficacy and safety from the randomised parallel phase 3 BE MOBILE 1 and BE MOBILE 2 studies

OBJECTIVES

Bimekizumab (BKZ), a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)-17F in addition to IL-17A, has demonstrated superior efficacy versus placebo in patients with non-radiographic (nr-) and radiographic (r-) axial spondyloarthritis (axSpA) at Week 16. Here, the objective is to report the efficacy and safety of BKZ at Week 52.

METHODS

BE MOBILE 1 (nr-axSpA; NCT03928704) and BE MOBILE 2 (r-axSpA; NCT03928743) comprised a 16-week, double-blind, placebo-controlled period, then a 36-week maintenance period. From Week 16, all patients received subcutaneous BKZ 160 mg every 4 weeks.

RESULTS

Improvements versus placebo in Assessment of SpondyloArthritis International Society ≥40% response (primary endpoint), Ankylosing Spondylitis Disease Activity Score, high-sensitivity C-reactive protein levels and MRI inflammation of the sacroiliac joints/spine at Week 16 were sustained to Week 52 in BKZ-randomised patients. At Week 52, responses of patients switching from placebo to BKZ at Week 16 were comparable to BKZ-randomised patients. At Week 52, ≥1 treatment-emergent adverse events (TEAEs) were reported in 183 (75.0%) and 249 (75.5%) patients with nr-axSpA and r-axSpA, respectively. Serious TEAEs occurred in 9 (3.7%) patients with nr-axSpA and 20 (6.1%) patients with r-axSpA. Oral candidiasis was the most frequent fungal infection (nr-axSpA: 18 (7.4%); r-axSpA: 20 (6.1%)). Uveitis occurred in three (1.2%) and seven (2.1%) patients with nr-axSpA and r-axSpA, and inflammatory bowel disease in two (0.8%) and three (0.9%).

CONCLUSIONS

At Week 52, dual inhibition of IL-17A and IL-17F with BKZ resulted in sustained efficacy across the axSpA spectrum; the safety profile was consistent with the known safety of BKZ.

TRIAL REGISTRATION NUMBER

NCT03928704; NCT03928743.

Safe and Effective Subcutaneous Self-Injection of Bimekizumab with Safety Syringe and Auto-Injector Devices: Results from a Multicenter, Randomized, Open-Label Study in Patients with Psoriatic Arthritis

Purpose

Bimekizumab is a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)-17F in addition to IL-17A, key drivers of chronic inflammation. Bimekizumab must be injected subcutaneously and so patients require self-injection options that meet their preferences. This study evaluated safe and effective self-injection of bimekizumab by patients with psoriatic arthritis using the 1 mL safety syringe (SSy) or the 1 mL auto-injector (AI).

Patients and Methods

The DV0004 devices study (NCT04109976) was a sub-study of BE VITAL, a multicenter, open-label extension of BE OPTIMAL (NCT03895203) and BE COMPLETE (NCT03896581) in patients with active psoriatic arthritis. After receiving training, patients subcutaneously self-injected bimekizumab 160 mg at Baseline and Week 4. The primary and secondary endpoints were the proportion of patients self-injecting bimekizumab safely and effectively at Week 4 and Baseline, respectively. Patient self-injection experience was evaluated using the pain visual analog scale (VAS) and the Self-Injection Assessment Questionnaire (SIAQ).

Results

Overall, 214 patients were randomized 1:1 at Baseline. All evaluable patients safely and effectively self-injected bimekizumab at Week 4 (SSy: n=105; AI: n=104) and Baseline (SSy: n=106; AI: n=106). Mean pain VAS scores were generally low at Week 4 (SSy: 11.0; AI: 11.4) and Baseline (SSy: 9.5; AI: 14.9). High mean pre- and post-injection SIAQ scores (≥6.7) were observed for both devices indicating a positive overall patient experience with self-injection. Self-injection was well tolerated with no reports of treatment-emergent adverse device effects (TEADEs), serious TEADEs or discontinuations due to TEADEs. Four non-device-related injection site reactions during the sub-study were reported in the parent study; all were mild, did not lead to discontinuation and resolved without treatment. All devices maintained their structural and functional integrity post-use.

Conclusion

All patients self-injected subcutaneous bimekizumab safely and effectively using either device at Baseline and Week 4. Overall, patients reported a positive self-injection experience.

Efficacy and safety of bimekizumab in axial spondyloarthritis: results of two parallel phase 3 randomised controlled trials

OBJECTIVES

Axial spondyloarthritis (axSpA) is a complex disease with diverse manifestations, for which new treatment options are warranted. BE MOBILE 1 (non-radiographic (nr)-axSpA) and BE MOBILE 2 (radiographic axSpA (r-axSpA)) are double-blind, phase 3 trials designed to evaluate efficacy and safety of bimekizumab, a novel dual interleukin (IL)-17A and IL-17F inhibitor, across the axSpA spectrum.

METHODS

In parallel 52-week trials, patients with active disease were randomised 1:1 (nr-axSpA) or 2:1 (r-axSpA) to bimekizumab 160 mg every 4 weeks:placebo. From week 16, all patients received bimekizumab 160 mg every 4 weeks. Primary (Assessment of SpondyloArthritis international Society ≥40% improvement (ASAS40)) and secondary endpoints were assessed at week 16. Here, efficacy and treatment-emergent adverse events (TEAEs) are reported up to week 24.

RESULTS

254 patients with nr-axSpA and 332 with r-axSpA were randomised. At week 16, primary (ASAS40, nr-axSpA: 47.7% bimekizumab vs 21.4% placebo; r-axSpA: 44.8% vs 22.5%; p<0.001) and all ranked secondary endpoints were met in both trials. ASAS40 responses were similar across TNFi-naïve and TNFi-inadequate responder patients. Improvements were observed in Ankylosing Spondylitis Disease Activity Score (ASDAS) states and objective measures of inflammation, including high-sensitivity C-reactive protein (hs-CRP) and MRI of the sacroiliac joints and spine. Most frequent TEAEs with bimekizumab (>3%) included nasopharyngitis, upper respiratory tract infection, pharyngitis, diarrhoea, headache and oral candidiasis. More fungal infections (all localised) were observed with bimekizumab vs placebo; no major adverse cardiovascular events (MACE) or active tuberculosis were reported. Incidence of uveitis and adjudicated inflammatory bowel disease was low.

CONCLUSIONS

Dual inhibition of IL-17A and IL-17F with bimekizumab resulted in significant and rapid improvements in efficacy outcomes vs placebo and was well tolerated in patients with nr-axSpA and r-axSpA.

Patient-reported distress as an early warning sign of unmet palliative care needs and increased healthcare utilization in patients with advanced cancer

INTRODUCTION

Cancer patients' sources of distress are often unaddressed, and patient-reported distress data could be utilized to identify those with unmet and impending care needs. We explored the association between moderate/severe distress and healthcare utilization in a large sample of non-small cell lung cancer (NSCLC) and non-colorectal gastrointestinal cancer patients.

METHODS AND MATERIALS

Adult patients treated between July 2013 and March 2019. Data from the NCCN Distress Thermometer (DT) and the accompanying "Problem List" were extracted from the EHR. A DT score of ≥ 4 indicates "actionable distress." Statistical analysis was performed using descriptive analysis for patient characteristics, clinical outcomes, and sources of distress. Generalized linear mixed models were fit to determine the relationship between distress and healthcare utilization (hospitalization, emergency department (ED) visit, or both).

RESULTS

The ten most frequently reported problems were from the Physical and Emotional domains of the Problem List. Distress was mostly related to physical symptoms (pain, fatigue) and emotional issues (worry, fears, sadness, nervousness). Patients with actionable distress generally reported more problems across all their visits. Actionable distress was associated with higher odds of the composite outcome measure of hospitalization or visiting the ED, within both the next 3 months (OR = 1.37; 95% CI = 1.19, 1.58; p < 0.001) and 6 months (OR = 1.19; 95% CI = 1.03, 1.37; p = 0.019).

CONCLUSION

Patients with significant distress had marked utilization of ED and inpatient services. DT scores are a source of untapped data in the EHR that can highlight patients in need of intervention, including palliative care and cancer support services.

Treatment-Related Changes in Left Atrial Structure in Atrial Fibrillation: Findings From the CABANA Imaging Substudy

[Figure: see text].

Implementation and Impact of a Risk-Stratified Prostate Cancer Screening Algorithm as a Clinical Decision Support Tool in a Primary Care Network

BACKGROUND

Implementation methods of risk-stratified cancer screening guidance throughout a health care system remains understudied.

OBJECTIVE

Conduct a preliminary analysis of the implementation of a risk-stratified prostate cancer screening algorithm in a single health care system.

DESIGN

Comparison of men seen pre-implementation (2/1/2016-2/1/2017) vs. post-implementation (2/2/2017-2/21/2018).

PARTICIPANTS

Men, aged 40-75 years, without a history of prostate cancer, who were seen by a primary care provider.

INTERVENTIONS

The algorithm was integrated into two components in the electronic health record (EHR): in Health Maintenance as a personalized screening reminder and in tailored messages to providers that accompanied prostate-specific antigen (PSA) results.

MAIN MEASURES

Primary outcomes: percent of men who met screening algorithm criteria; percent of men with a PSA result. Logistic repeated measures mixed models were used to test for differences in the proportion of individuals that met screening criteria in the pre- and post-implementation periods with age, race, family history, and PSA level included as covariates.

KEY RESULTS

During the pre- and post-implementation periods, 49,053 and 49,980 men, respectively, were seen across 26 clinics (20.6% African American). The proportion of men who met screening algorithm criteria increased from 49.3% (pre-implementation) to 68.0% (post-implementation) (p < 0.001); this increase was observed across all races, age groups, and primary care clinics. Importantly, the percent of men who had a PSA did not change: 55.3% pre-implementation, 55.0% post-implementation. The adjusted odds of meeting algorithm-based screening was 6.5-times higher in the post-implementation period than in the pre-implementation period (95% confidence interval, 5.97 to 7.05).

CONCLUSIONS

In this preliminary analysis, following implementation of an EHR-based algorithm, we observed a rapid change in practice with an increase in screening in higher-risk groups balanced with a decrease in screening in low-risk groups. Future efforts will evaluate costs and downstream outcomes of this strategy.

Overcoming underpowering: Trial simulations and a global rank end point to optimize clinical trials in children with heart disease

BACKGROUND

Randomized controlled trials (RCTs) in children with heart disease are challenging and therefore infrequently performed. We sought to improve feasibility of perioperative RCTs for this patient cohort using data from a large, multicenter clinical registry. We evaluated potential enrollment and end point frequencies for various inclusion cohorts and developed a novel global rank trial end point. We then performed trial simulations to evaluate power gains with the global rank end point and with use of planned covariate adjustment as an analytic strategy.

METHODS

Data from the Society of Thoracic Surgery-Congenital Heart Surgery Database (STS-CHSD, 2011-2016) were used to support development of a consensus-based global rank end point and for trial simulations. For Monte Carlo trial simulations (n = 50,000/outcome), we varied the odds of outcomes for treatment versus placebo and evaluated power based on the proportion of trial data sets with a significant outcome (P < .05).

RESULTS

The STS-CHSD study cohort included 35,967 infant index cardiopulmonary bypass operations from 103 STS-CHSD centers, including 11,411 (32%) neonatal cases and 12,243 (34%) high-complexity (Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality category ≥4) cases. In trial simulations, study power was 21% for a mortality-only end point, 47% for a morbidity and mortality composite, and 78% for the global rank end point. With covariate adjustment, power increased to 94%. Planned covariate adjustment was preferable to restricting to higher-risk cohorts despite higher event rates in these cohorts.

CONCLUSIONS

Trial simulations can inform trial design. Our findings, including the newly developed global rank end point, may be informative for future perioperative trials in children with heart disease.

Rationale and design of the STeroids to REduce Systemic inflammation after infant heart Surgery (STRESS) trial

For decades, physicians have administered corticosteroids in the perioperative period to infants undergoing heart surgery with cardiopulmonary bypass (CPB) to reduce the postoperative systemic inflammatory response to CPB. Some question this practice because steroid efficacy has not been conclusively demonstrated and because some studies indicate that steroids could have harmful effects. STRESS is a randomized, placebo-controlled, double-blind, multicenter trial designed to evaluate safety and efficacy of perioperative steroids in infants (age < 1 year) undergoing heart surgery with CPB. Participants (planned enrollment = 1,200) are randomized 1:1 to methylprednisolone (30 mg/kg) administered into the CPB pump prime versus placebo. The trial is nested within the existing infrastructure of the Society of Thoracic Surgeons Congenital Heart Surgery Database. The primary outcome is a global rank score of mortality, major morbidities, and hospital length of stay with components ranked commensurate with their clinical severity. Secondary outcomes include several measures of major postoperative morbidity, postoperative hospital length of stay, and steroid-related safety outcomes including prevalence of hyperglycemia and postoperative infectious complications. STRESS will be one of the largest trials ever conducted in children with heart disease and will answer a decades-old question related to safety and efficacy of perioperative steroids in infants undergoing heart surgery with CPB. The pragmatic "trial within a registry" design may provide a mechanism for conducting low-cost, high-efficiency trials in a heretofore-understudied patient population.

Myocardial Viability and Long-Term Outcomes in Ischemic Cardiomyopathy

BACKGROUND

The role of assessment of myocardial viability in identifying patients with ischemic cardiomyopathy who might benefit from surgical revascularization remains controversial. Furthermore, although improvement in left ventricular function is one of the goals of revascularization, its relationship to subsequent outcomes is unclear.

METHODS

Among 601 patients who had coronary artery disease that was amenable to coronary-artery bypass grafting (CABG) and who had a left ventricular ejection fraction of 35% or lower, we prospectively assessed myocardial viability using single-photon-emission computed tomography, dobutamine echocardiography, or both. Patients were randomly assigned to undergo CABG and receive medical therapy or to receive medical therapy alone. Left ventricular ejection fraction was measured at baseline and after 4 months of follow-up in 318 patients. The primary end point was death from any cause. The median duration of follow-up was 10.4 years.

RESULTS

CABG plus medical therapy was associated with a lower incidence of death from any cause than medical therapy alone (182 deaths among 298 patients in the CABG group vs. 209 deaths among 303 patients in the medical-therapy group; adjusted hazard ratio, 0.73; 95% confidence interval, 0.60 to 0.90). However, no significant interaction was observed between the presence or absence of myocardial viability and the beneficial effect of CABG plus medical therapy over medical therapy alone (P = 0.34 for interaction). An increase in left ventricular ejection fraction was observed only among patients with myocardial viability, irrespective of treatment assignment. There was no association between changes in left ventricular ejection fraction and subsequent death.

CONCLUSIONS

The findings of this study do not support the concept that myocardial viability is associated with a long-term benefit of CABG in patients with ischemic cardiomyopathy. The presence of viable myocardium was associated with improvement in left ventricular systolic function, irrespective of treatment, but such improvement was not related to long-term survival. (Funded by the National Institutes of Health; STICH ClinicalTrials.gov number, NCT00023595.).

Variants Associated with the Ankle Brachial Index Differ by Hispanic/Latino Ethnic Group: a genome-wide association study in the Hispanic Community Health Study/Study of Latinos

Lower extremity peripheral artery disease (PAD) burden differs by race/ethnicity. Although familial aggregation and heritability studies suggest a genetic basis, little is known about the genetic susceptibility to PAD, especially in non-European descent populations. Genome-wide association studies (GWAS) of the ankle brachial index (ABI) and PAD (defined as an ABI < 0.90) have not been conducted in Hispanics/Latinos. We performed a GWAS of PAD and the ABI in 7,589 participants aged >45 years from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). We also performed GWAS for ABI stratified by Hispanic/Latino ethnic subgroups: Central American, Mexican, and South American (Mainland group), and Cuban, Dominican, and Puerto Rican (Caribbean group). We detected two genome-wide significant associations for the ABI in COMMD10 in Puerto Ricans, and at SYBU in the Caribbean group. The lead SNP rs4466200 in the COMMD10 gene had a replication p = 0.02 for the ABI in Multi-Ethnic Study of Atherosclerosis (MESA) African Americans, but it did not replicate in African Americans from the Cardiovascular Health Study (CHS). In a regional look-up, a nearby SNP rs12520838 had Bonferroni adjusted p = 0.05 (unadjusted p = 7.5 × 10⁻⁵) for PAD in MESA Hispanics. Among three suggestive associations (p < 10⁻⁷) in subgroup-specific analyses, DMD on chromosome X, identified in Central Americans, replicated in MESA Hispanics (p = 2.2 × 10⁻⁴). None of the previously reported ABI and PAD associations in whites generalized to Hispanics/Latinos.

Femoral Artery Atherosclerosis Is Associated With Physical Function Across the Spectrum of the Ankle-Brachial Index: The San Diego Population Study

Background

The ankle‐brachial index (ABI) is inadequate to detect early‐stage atherosclerotic disease, when interventions to prevent functional decline may be the most effective. We determined associations of femoral artery atherosclerosis with physical functioning, across the spectrum of the ABI, and within the normal ABI range.

Methods and Results

In 2007–2011, 1103 multiethnic men and women participated in the San Diego Population Study, and completed all components of the summary performance score. Using Doppler ultrasound, superficial and common femoral intima media thickness and plaques were ascertained. Logistic regression was used to assess associations of femoral atherosclerosis with the summary performance score and its individual components. Models were adjusted for demographics, lifestyle factors, comorbidities, lipids, and kidney function. In adjusted models, among participants with a normal‐range ABI (1.00–1.30), the highest tertile of superficial intima media thickness was associated with lower odds of a perfect summary performance score of 12 (odds ratio=0.56 [0.36, 0.87], P=0.009), and lower odds of a 4‐m walk score of 4 (0.34 [0.16, 0.73], P=0.006) and chair rise score of 4 (0.56 [0.34, 0.94], P=0.03). Plaque presence (0.53 [0.29, 0.99], P=0.04) and greater total plaque burden (0.61 [0.43, 0.87], P=0.006) were associated with worse 4‐m walk performance in the normal‐range ABI group. Higher superficial intima media thickness was associated with lower summary performance score in all individuals (P=0.02).

Conclusions

Findings suggest that use of femoral artery atherosclerosis measures may be effective in individuals with a normal‐range ABI, especially, for example, those with diabetes mellitus or a family history of peripheral artery disease, when detection can lead to earlier intervention to prevent functional declines and improve quality of life.

Do pollinators contribute to nutritional health?

Despite suggestions that animal pollinators are crucial for human nutritional health, no studies have actually tested this claim. Here, we combined data on crop pollination requirements, food nutrient densities, and actual human diets to predict the effects of pollinator losses on the risk of nutrient deficiency. In four developing countries and across five nutrients, we found that 0 to 56% of populations would become newly at risk if pollinators were removed. Increases in risk were most pronounced for vitamin A in populations with moderate levels of total nutrient intake. Overall, the effects of pollinator decline varied widely among populations and nutrients. We conclude that the importance of pollinators to human nutrition depends critically on the composition of local diets, and cannot be reliably predicted from global commodity analyses. We identify conditions under which severe health effects of pollinator loss are most likely to occur.

Recasting the theory of mosquito-borne pathogen transmission dynamics and control

Mosquito-borne diseases pose some of the greatest challenges in public health, especially in tropical and sub-tropical regions of the world. Efforts to control these diseases have been underpinned by a theoretical framework developed for malaria by Ross and Macdonald, including models, metrics for measuring transmission, and theory of control that identifies key vulnerabilities in the transmission cycle. That framework, especially Macdonald's formula for R₀ and its entomological derivative, vectorial capacity, are now used to study dynamics and design interventions for many mosquito-borne diseases. A systematic review of 388 models published between 1970 and 2010 found that the vast majority adopted the Ross–Macdonald assumption of homogeneous transmission in a well-mixed population. Studies comparing models and data question these assumptions and point to the capacity to model heterogeneous, focal transmission as the most important but relatively unexplored component in current theory. Fine-scale heterogeneity causes transmission dynamics to be nonlinear, and poses problems for modeling, epidemiology and measurement. Novel mathematical approaches show how heterogeneity arises from the biology and the landscape on which the processes of mosquito biting and pathogen transmission unfold. Emerging theory focuses attention on the ecological and social context for mosquito blood feeding, the movement of both hosts and mosquitoes, and the relevant spatial scales for measuring transmission and for modeling dynamics and control.

A systematic review of mathematical models of mosquito-borne pathogen transmission: 1970-2010

Mathematical models of mosquito-borne pathogen transmission originated in the early twentieth century to provide insights into how to most effectively combat malaria. The foundations of the Ross–Macdonald theory were established by 1970. Since then, there has been a growing interest in reducing the public health burden of mosquito-borne pathogens and an expanding use of models to guide their control. To assess how theory has changed to confront evolving public health challenges, we compiled a bibliography of 325 publications from 1970 through 2010 that included at least one mathematical model of mosquito-borne pathogen transmission and then used a 79-part questionnaire to classify each of 388 associated models according to its biological assumptions. As a composite measure to interpret the multidimensional results of our survey, we assigned a numerical value to each model that measured its similarity to 15 core assumptions of the Ross–Macdonald model. Although the analysis illustrated a growing acknowledgement of geographical, ecological and epidemiological complexities in modelling transmission, most models during the past 40 years closely resemble the Ross–Macdonald model. Modern theory would benefit from an expansion around the concepts of heterogeneous mosquito biting, poorly mixed mosquito-host encounters, spatial heterogeneity and temporal variation in the transmission process.

Parameterization and sensitivity analysis of a complex simulation model for mosquito population dynamics, dengue transmission, and their control

Models can be useful tools for understanding the dynamics and control of mosquito-borne disease. More detailed models may be more realistic and better suited for understanding local disease dynamics; however, evaluating model suitability, accuracy, and performance becomes increasingly difficult with greater model complexity. Sensitivity analysis is a technique that permits exploration of complex models by evaluating the sensitivity of the model to changes in parameters. Here, we present results of sensitivity analyses of two interrelated complex simulation models of mosquito population dynamics and dengue transmission. We found that dengue transmission may be influenced most by survival in each life stage of the mosquito, mosquito biting behavior, and duration of the infectious period in humans. The importance of these biological processes for vector-borne disease models and the overwhelming lack of knowledge about them make acquisition of relevant field data on these biological processes a top research priority.

Electron attachment and electron ionization of acetic acid clusters embedded in helium nanodroplets

The effect of incident electrons on acetic acid clusters is explored for the first time. The acetic acid clusters are formed inside liquid helium nanodroplets and both cationic and anionic products ejected into the gas phase are detected by mass spectrometry. The cation chemistry (induced by electron ionization at 100 eV) is dominated by production of protonated acetic acid (Ac) clusters, Ac(n)H(+), although some fragmentation is also observed. In the case of anion production (at 2.8 eV electron energy) there is a clear distinction between the monomer and the clusters. For the monomer the dominant product is the dehydrogenated species, [Ac-H](-), whereas for the clusters both the parent anion, Ac(n)(-), and the dehydrogenated species, [Ac(n)-H](-), have similar abundances. A particularly intriguing contrast between the monomer and cluster anions is that helium atoms are seen attached to the latter whereas no evidence of helium atom attachment is found for the monomer. This surprising observation is attributed to the formation of acyclic (head-to-tail) acetic acid clusters in helium nanodroplets, which have more favourable electronic properties for binding helium atoms. The acyclic clusters represent a local minimum on the potential energy surface and in the case of the dimer this is distinct from the cyclic isomer (the global minimum) identified in gas phase experiments.

The efficacy of small cell foundation as a varroa mite (Varroa destructor) control

Due to a continuing shift toward reducing/minimizing the use of chemicals in honey bee colonies, we explored the possibility of using small cell foundation as a varroa control. Based on the number of anecdotal reports supporting small cell as an efficacious varroa control tool, we hypothesized that bee colonies housed on combs constructed on small cell foundation would have lower varroa populations and higher adult bee populations and more cm(2) brood. To summarize our results, we found that the use of small cell foundation did not significantly affect cm(2) total brood, total mites per colony, mites per brood cell, or mites per adult bee, but did affect adult bee population for two sampling months. Varroa levels were similar in all colonies throughout the study. We found no evidence that small cell foundation was beneficial with regard to varroa control under the tested conditions in Florida.

Novel gas-stabilized iron clusters: synthesis, structure and magnetic behaviour

A novel method for the synthesis of nanostructured films produced by depositing gas-phase magnetic nanoparticles is presented and the properties of the films are reported. The technique mixes metal vapour and small argon clusters produced in a supersonic expansion. The condensed clusters are subsequently deposited in situ onto copper grids. The cluster size is controlled by the vapour pressure of the metal inside the pick-up chamber. Detailed analysis of the transmission electron micrographs of the Fe clusters shows that there is a simple linear relationship between the average metal cluster diameter and the metal vapour pressure during deposition. Furthermore, the nanoparticles show a relatively narrow size distribution for a given set of experimental conditions. Structural and magnetic investigations have been performed on Fe cluster samples, and the influence of the metal vapour pressure has been studied. Detailed analysis of the magnetic and structural data has been performed and valuable information such as cluster size distributions, strength of the interparticle dipolar interactions and average magnetic moment per cluster are derived. It is shown that, at room temperature, the magnetic behaviour of the films is consistent with nanoparticle supermoments interacting via dipolar interactions.

Incorporating density dependence into the oviposition preference-offspring performance hypothesis

1. Although theory predicts a positive relationship between oviposition preferences and the developmental performance of offspring, the strength of this relationship may depend not only on breeding site quality, but also on the complex interactions between environmental heterogeneity and density-dependent processes. Environmental heterogeneity may not only alter the strength of density dependence, but may also fundamentally alter density-dependent relationships and the preference-performance relationship. 2. Here I present results from a series of field experiments testing the effects of environmental heterogeneity and density-dependent feedback on offspring performance in tree-hole mosquitoes. Specifically, I asked: (i) how do oviposition activity, patterns of colonization and larval density differ among habitats and among oviposition sites with different resources; and (ii) how is performance influenced by the density of conspecifics, the type of resource in the oviposition site, and the type of habitat in which the oviposition site is located? 3. Performance did not differ among habitats at low offspring densities, but was higher in deciduous forest habitats than in evergreen forest habitats at high densities. Oviposition activity and larval densities were also higher in deciduous forests, suggesting a weak preference for these habitats. 4. The observed divergence of fitness among habitats with increasing density may select for consistent but weak preferences for deciduous habitats if regional abundances vary temporally. This would generate a negative preference-performance relationship when population densities are low, but a positive relationship when population densities are high. 5. This study demonstrates that failure to recognize that fitness differences among habitats may themselves be density-dependent may bias our assumptions about the ecological and evolutionary processes determining oviposition preferences in natural systems.

Evaluating the long-term metacommunity dynamics of tree hole mosquitoes

Four different conceptual models of metacommunities have been proposed, termed "patch dynamics," "species sorting", "mass effect", and "neutral". These models simplify thinking about metacommunities and improve our understanding of the role of spatial dynamics both in structuring communities and in determining local and regional diversity. We tested whether mosquito communities inhabiting water-filled tree holes in southeastern Florida, U.S.A., displayed any of the characteristics and dynamics predicted by the four models. The densities of the five most common species in 3-8 tree holes were monitored every two weeks during 1978-2003. We tested relationships between habitat variables and species densities, spatial synchrony, the presence of life history trade-offs, and species turnover. Dynamics showed strong elements of species sorting, but with considerable turnover, as predicted by the patch dynamics model. Consistent with patch dynamics, there was substantial asynchrony in dynamics for different tree holes, substantial species turnover in space and time, and an occupancy/colonization trade-off. Substantial correlations of density and occupancy with tree hole volume were consistent with the species-sorting model, but unlike this model, species did not have permanent refuges. No evidence of mass effects was found, and correlations between habitat variables and dynamics were inconsistent with neutral models. Our results did not match a single model and therefore caution against overly simplifying metacommunity dynamics by using one dynamical characteristic to select a particular metacommunity perspective.

Hybrid external fixation in complex tibial plateau and plafond fractures: an Australian audit of outcomes

Hybrid external fixators are useful for the management of complex tibial plateau and plafond fractures, as they provide rigid fixation with relatively minimal soft tissue disruption. We reviewed the outcomes of patients with proximal (plateau) and distal (plafond) tibial fractures who were treated with hybrid frames at the Royal North Shore Hospital from 1998 to 2001. Twenty-four patients were identified from the hospital operating records and chart, X-ray and clinical reviews were performed. Follow-up periods averaged 13 months. Fractures were classified using the Ruedi classification for ankle fractures, and the Schatzker classification for the knee fractures. Clinical outcome was assessed using the Iowa knee score and the AOFAS ankle score. As one of the first Australian audits our outcomes were consistent with international standards.

Osteomyelitis and pyogenic sacroiliitis: A difficult diagnosis

Pyogenic sacroiliitis is an uncommon infection often diagnosed late because of poor localization of symptoms and inadequate physical examination. We describe a 12-year-old girl whose osteomyelitis and pyogenic sacroiliitis was initially misdiagnosed and discuss examination, investigation and management of the condition. This case highlights the importance of thorough physical examination and the consideration of septic arthritis in an unusual joint.

Population response to climate change: linear vs. non-linear modeling approaches

BACKGROUND

Research on the ecological consequences of global climate change has elicited a growing interest in the use of time series analysis to investigate population dynamics in a changing climate. Here, we compare linear and non-linear models describing the contribution of climate to the density fluctuations of the population of wolves on Isle Royale, Michigan from 1959 to 1999.

RESULTS

The non-linear self excitatory threshold autoregressive (SETAR) model revealed that, due to differences in the strength and nature of density dependence, relatively small and large populations may be differentially affected by future changes in climate. Both linear and non-linear models predict a decrease in the population of wolves with predicted changes in climate.

CONCLUSIONS

Because specific predictions differed between linear and non-linear models, our study highlights the importance of using non-linear methods that allow the detection of non-linearity in the strength and nature of density dependence. Failure to adopt a non-linear approach to modelling population response to climate change, either exclusively or in addition to linear approaches, may compromise efforts to quantify ecological consequences of future warming.

Prison construction and guarding behaviour by European honeybees is dependent on inmate small hive beetle density

Increasing small hive beetle (Aethina tumida Murray) density changes prison construction and guarding behaviour in European honeybees (Apis mellifera L.). These changes include more guard bees per imprisoned beetle and the construction of more beetle prisons at the higher beetle density. Despite this, the number of beetles per prison (inmate density) did not change. Beetles solicited food more actively at the higher density and at night. In response, guard bees increased their aggressive behaviour towards beetle prisoners but did not feed beetles more at the higher density. Only 5% of all beetles were found among the combs at the low density but this percentage increased five-fold at the higher one. Successful comb infiltration (and thus reproduction) by beetles is a possible explanation for the significant damage beetles cause to European honeybee colonies in the USA.

Use of simulation technology in Australian Defence Force resuscitation training

Realistic training of health personnel for the resuscitation of military casualties is problematic. There are few opportunities for personnel to obtain the necessary experience unless working in a busy emergency or trauma environment. Even so, the specific nature of military trauma means that many aspects of casualty management may not be adequately covered in the civilian domain. This paper discusses the use of advanced simulation technology in the training of military resuscitation teams. Such training has been available to members of the Australian Defence Force (ADF) for two years.

Excitation evoked by FMRFamide and FLRFamide in the heart of Buccinum undatum and evidence for inositol 1,4,5-trisphosphate as an RF-tetrapeptide second messenger

In this study the relative potencies of four established molluscan cardioexcitatory agents were examined on Buccinum heart. The potencies were, in decending order: phenylalanine-leucine-arginine-phenylalanine-NH2 (FLRFamide) > phenylalanine-methionine-arginine-phenylalanine-NH2 (FMRFamide; 80% of maximum) > 5-hydroxytryptamine (5HT; 60% of maximum) > guanosine triphosphate (GTP; 15% of maximum). FMRFamide and FLRFamide had similar dose-response curve patterns with thresholds at 10(-9) mol l(-1) but FLRFamide was more potent than FMRFamide. The superfused atrium was much less sensitive to all agonists than the internally perfused ventricle. FLRFamide and FMRFamide induced small depolarizations (1-2 mV) which triggered a burst of action potentials of about 5 mV which on reaching 4 mV triggered a burst of fast twitch contractions. Lithium, at high concentrations inhibited FMRFamide and 5-HT responses of internally perfused ventricles. Neomycin also inhibited peptide responses, but was without effect on 5-HT responses. Heparin, however, for technical reasons was without effect on ventricular responses to all three agonists. FMRFamide and FLRFamide appear to share a common receptor, the potency difference being due to the substitution of leucine for methionine in FLRFamide. The RF N-terminal sequence appears crucial for receptor activation. The Phospholipase C inhibitor neomycin equally inhibits responses to the two peptides while 5-HT responses are unaffected. This implicates a peptide/receptor interaction which activated inositol 1,4,5-trisphosphate (IP3) as a second messenger.

Intravertebral spinal neurenteric cysts: a unique radiographic sign--"the hole-in-one vertebra"

A well-defined circular defect in the midst of a complex vertebral anomaly, visible on a plain radiograph, is diagnostic of an intravertebral extension of a neurenteric cyst. It may represent a connecting stalk between a mediastinal cyst and an intraspinal lesion. The "hole-in-one" vertebra is an indication for a magnetic resonance imaging (MRI) scan. When surgical excision of a mediastinal cyst is undertaken, the intravertebral tract should be curetted to avoid recurrence.

Intra-articular local anaesthesia for pain after hip arthroplasty

We investigated 15 patients with painful hip arthroplasties using intra-articular injection of bupivicaine. Fourteen had pain relief and 13 of them were subsequently found to have loosening of one or both components. The relief of pain after total hip arthroplasty by intra-articular injection of bupivicaine indicates that a satisfactory result is probable after revision surgery with refixation of the components.

First Spectroscopic Observation of the CdC2H5 Radical

We report the first spectroscopic observation of the monoethyl cadmium free radical, CdC2H5, using laser-induced fluorescence spectroscopy. This molecule was prepared in a supersonic jet by reaction of cadmium atoms with an ethyl precursor in a recently developed dual-channel electrical discharge nozzle. The laser excitation spectrum of CdC2H5 consists of a single, unresolved, band attributed to the A-X origin transition. However, the dispersed fluorescence spectrum obtained by laser-pumping the origin transition does show some vibrational structure. A short progression in the Cd-C stretching mode has been observed giving a frequency of 280 cm-1 for this mode. Comparison with the related molecule ZnC2H5 shows that the increase in reduced mass is not sufficient to account for the much lower metal-carbon stretching frequency in CdC2H5 and the evidence therefore points to a substantially weaker metal-carbon bond in the latter. The absence of vibrational structure in the excitation spectrum of CdC2H5 is attributed to the depopulation of excited vibronic levels by predissociation. Copyright 1997 Academic Press. Copyright 1997Academic Press

Dispersed Fluorescence Spectroscopy of the ZnC2H5 Free Radical

Dispersed fluorescence spectra of the zinc monoethyl radical are presented. These have allowed vibrational frequencies of several modes in the ground electronic state of this molecule to be determined for the first time. In particular, substantial activity in both the Zn-C stretch and the Zn-C-C bend has been observed, with the frequencies for these modes being deduced as 387 and 180 cm-1, respectively. With the aid of the dispersed fluorescence data it has also proved possible to make reasonable assignments for several bands in the excitation spectrum. ZnC2H5 was prepared in these experiments by a dc electrical discharge through an argon/diethyl zinc mixture in a supersonic nozzle. Copyright 1997 Academic Press. Copyright 1997Academic Press

Bizarre parosteal osteochondromatous proliferation: a review of seven cases

BACKGROUND

Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare tumour-like condition mostly affecting the tubular bones of the hands and feet. Although it recurs in 50% of cases after local excision, it is a form of heterotopic ossification and its behaviour is otherwise benign. The present study describes seven cases of BPOP collected by the Bone Tumour Registry of New South Wales.

METHODS

Clinical data, radiographs and histological specimens collected by the Bone Tumour Registry of New South Wales were examined, and further clinical data were sought from the referring doctor where necessary.

RESULTS

Six males and one female aged 18 to 37 years (median 30 years) presented between 1988 and 1995. There were three cases involving the hands, three involving the feet and one involving the distal humerus. Initial treatment was by local excision in all cases. There was local recurrence in three cases. The initial diagnosis was wrong in five of the seven cases. Radiologically, BPOP appears as a well-defined tumour arising directly from the bony cortex, without periosteal reaction or change to the underlying bone. Histologically, a large amount of hypercellular cartilage shows maturation to trabecular bone, which frequently contains spindle cells in the intertrabecular spaces.

CONCLUSION

BPOP is a rare, locally recurrent but otherwise benign condition of bone which must be distinguished from more sinister lesions such as parosteal osteosarcoma and chondrosarcoma.

Sexual abuse and drinking and drug use: implications for prevention

Based on a survey of adolescent females in grades seven through twelve in a suburban school system, the relationship between drinking, drug use, and sexual abuse is examined. Using a holistic approach to adolescent deviant behavior, connections between family, peer, psychosocial factors and drug use and delinquency are explored. Girls who report sexual molestation are more likely to have used a number of drugs, different from the prevalence profile of the larger sample. Significant correlations for younger girls between sexual molestation and delinquency are also reported. Implications for school based drug prevention programs are discussed.

Contribution of antiplatelet activity to the effects of 5-HT2 receptor antagonists on reperfusion-induced arrhythmias in anaesthetized rats

The effects of certain 5-HT receptor antagonists were examined on ischaemia-induced and reperfusion-induced arrhythmias, on ex vivo platelet aggregation and on isolated cardiac muscle. Methiothepin (1 mg kg-1) reduced the total number of ischaemia-induced ventricular premature beats whereas ICI 170,809 (1 mg kg-1) reduced reperfusion-induced mortality to 10% compared with 70% in controls. ICI 169,369 did not significantly alter either ischaemia- or reperfusion-induced arrhythmias. High concentrations of both ICI 169,369 and ICI 170,809 caused reductions in the maximum driving frequency of isolated cardiac muscle but methiothepin had no significant effect. Administration of ketanserin, ritanserin, methiothepin or ICI 170,809, but not ICI 169,369, abolished the ability of 5-HT to enhance platelet aggregation. The results of these experiments suggest that the ability of 5-HT2 receptor antagonists to reduce reperfusion-induced arrhythmias may be related to their antiplatelet activity.

Five year outcome of preterm sextuplets related to size at birth

Preterm sextuplets were studied to examine whether growth retardation affects long term outcome. All were growing normally at 5 years. Intelligence quotients (IQ) ranged from 105-116 and motor impairment scores from 1.0-7.0. No neurological or behavioural abnormalities were found. The largest sextuplet has maintained her position for growth and IQ. No relation between test scores and birth weight or perinatal variables was found in the remaining siblings.

Directed-donor programs may adversely affect autologous donor participation

One hundred autologous whole blood donors (11 men, 89 women; 49 preoperative, 51 prenatal) completed a questionnaire concerning their motivations as autologous donors, their perceptions of the relative safety of blood donor options, and their interest in directed donations. Concern about acquiring AIDS from transfusion was the most prevalent reason for autologous donation. Nearly all participants knew that autologous blood was safer than volunteer blood, and most also believed that directed-donor blood was safer than volunteer blood. Most would have used a directed-donor program if available, particularly if they were ineligible as autologous donors. Furthermore, their interest in directed donations was unaffected by written material, provided pathway through the questionnaire, that included a statement that no scientific evidence exists to support directed donations' being safer than volunteer blood. One donor in five believed that autologous and directed donations were equivalent in safety, and 19 (15 of whom were prenatal donors) indicated that they probably or surely would not have participated in the autologous program if directed donations had been available. This study demonstrates that a sizable proportion of autologous donor candidates might not participate if a directed donation program were available. The unrestricted availability of directed donations may thus contribute to suboptimal use of autologous donor programs.

Ketanserin and ritanserin can reduce reperfusion-induced but not ischaemia-induced arrhythmias in anaesthetised rats

The effects of the 5-hydroxytryptamine2 (5-HT2) antagonists ketanserin and ritanserin on ischaemia- and reperfusion-induced arrhythmias were investigated in pentobarbitone-anaesthetised rats. Both ketanserin (3 mg kg-1) and ritanserin (1 mg kg-1) significantly reduced the incidence of ventricular fibrillation (from 60 to 25% and 88 to 12%, respectively) and the mortality induced by reperfusion after 5 min of myocardial ischaemia. Neither drug significantly altered the number of ventricular ectopic beats, the incidence of ventricular tachycardia, ventricular fibrillation, or mortality during the first 25 min of coronary artery occlusion. Significant dose-dependent reductions in heart rate and arterial blood pressure were observed with all doses of ketanserin (0.1-3 mg kg-1) and ritanserin (0.3 and 1 mg kg-1), but neither drug had any major effect on arterial blood gases or pH. In isolated guinea pig and rat atria and ventricular muscle preparations, ketanserin (10(-5) M) and ritanserin (3 X 10(-5) M) reduced the maximal driving frequency, whereas 5-HT itself was without effect. The results suggest that the antiarrhythmic activity of ketanserin and ritanserin observed in this study was probably not due to 5-HT2 receptor or alpha 1-adrenoceptor blockade, but may have been due to a direct action on cardiac muscle.