Case for rethinking system leadership and its development in public health

Background

There is growing recognition of the importance of leadership in Public Health (PH) practice, and the need to embed it into the education and training of PH professionals. However the theoretical discourse within leadership research has changed significantly and there is recognition that previous conceptualisations of leadership, and our ways of developing it may be flawed, and need to be changed in practice.

Objectives

This presentation will discuss development of leadership theory, and system leadership. In particular it will highlight how System Leadership differs from previous understandings of leadership and the implications of this for ph practitioners and those charged with developing system leadership capacity within public health.

Body of the session

Leadership in organisations is mostly focused on current/anticipated internal challenges (strategy, performance management, staff engagement, etc.). Leaders are generally developed via individual leader development rather than a focus developing Leadership capacity across organisations/systems. Within PH it is increasingly realised that single organisations can no longer respond effectively to the “wicked” issues they face. They do not possess sufficient know-how to address the complex and multi-dimensional problems faced, so leadership models based on a single hierarchical organisation are not sustainable. There is a need to work collectively in an ecosystem-based approach (not an ego-based system). System Leadership development requires that participants are actively engaged in real attempts to improve PH System. Development requires that underlying values are made explicit, explored and diversity embraced. The emphasis will be on supporting learners in the doing rather than critiquing or talking about it.

Conclusions

There is need to appreciate fully the nature of systems leadership, together with implications for PH practice and the development of system leadership capacity throughout the PH workforce.

SAT0182 THE ASSOCIATION BETWEEN AUTOANTIBODIES AND RITUXIMAB RESPONSE IN SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Systemic Lupus Erythematosus (SLE) is clinically and immunologically heterogeneous with a variable response to treatment. MASTERPLANS is an MRC-funded consortium that seeks to identify immunophenotypic subgroups of patients that predict response to therapy. Autoantibody profiles can differentiate subgroups of patients and have potential to predict response to treatment.

Objectives:

To determine whether known and novel autoantibodies are associated with response to rituximab (RTX), and analyse the association between these antibodies and disease involvement in various organ systems.

Methods:

Serum was obtained from 224 SLE patients in the BILAG Biologics Registry who received rituximab according to NHS England criteria (2). Patients were recruited if they were starting a first cycle of rituximab for active SLE (BILAG A or 2xBILAG B) despite previous cyclophosphamide or mycophenolate mofetil. Evidence of any single organ system involvement previous or current was taken as having a BILAG score of A-D but not E. Disease activity was measured using BILAG-2004. Clinical response was defined as improvement by >=1 grade in active BILAG-2004 systems with no worsening in other systems. Autoantibodies were measured by immunoprecipitation of proteins by sera from35S-labelled K562 cell lines, followed by SDS-PAGE separation and autoradiography. Autoantibodies not able to be detected by this technique (anti-Ro52, anti-dsDNA and aCL) were measured by ELISA. Autoantibody data was analysed in IBM SPSS and GraphPad Prism v8.2. Association between autoantibodies and RTX response was analysed using binary logistic interaction terms and Pearson’s Chi-Square test.

Results:

Of the 224 patients (201 female, 23 male, median age 40 years) the most common system involvement from the 9 BILAG domains was musculoskeletal (164 patients) and the least ophthalmic (11 patients). Patients with anti-Ro52 and anti-U1RNP/Sm had more frequent involvement of mucocutaneous (p<0.036,p<0.012) and musculoskeletal domains (p<0.015 for U1RNP) respectively.

There were 136 patients with sufficient data to define as either responders (n=67) or non-responders (n=69) to RTX at 6 months. RTX responders had a higher frequency of anti-U1RNP/Sm compared to non-responders (Figure 1). Further Pearson’s Chi-Square analysis showed a significant association between presence of anti-U1RNP/Sm and better response to RTX (p<0.018).

Conclusion:

Our findings suggest that the presence of U1RNP/Sm autoantibodies in a cohort of patients who have received treatment with RTX is associated with more frequent musculoskeletal and mucocutaneous involvement and predicts a more favourable response to treatment.

Acknowledgments :

Funded by a grant from the Medical Research Council, grant number MR/M01665X/1. BILAG BR has been funded by unrestricted educational donations from Roche, GSK and LUPUS UK. Part-funded by a grant from LUPUS UK.

Disclosure of Interests: :

Danyang Li: None declared, Hui Lu: None declared, Juliet Dunphy: None declared, Theresa Smith: None declared, Edward Vital Grant/research support from: AstraZeneca, Roche/Genentech, and Sandoz, Consultant of: AstraZeneca, GSK, Roche/Genentech, and Sandoz, Speakers bureau: Becton Dickinson and GSK, Ian N. Bruce Grant/research support from: Genzyme Sanofi, GSK, and UCB, Consultant of: Eli Lilly, AstraZeneca, UCB, Iltoo, and Merck Serono, Speakers bureau: UCB, Neil McHugh: None declared

THU0209 UPTAKE OF JANUS KINASE INHIBITORS FOR MANAGEMENT OF RHEUMATOID ARTHRITIS IN AUSTRALIA

Background:

JAK inhibitors (JAKi) are oral tsDMARDs with a different mode of action (MOA) to both oral cs- and parenteral bDMARDs. In Australia the cost of b/tsDMARDs for treatment of RA is subsidized if the patient has documented high levels of clinical/laboratory disease activity and has not responded to a pre-specified combination of csDMARDs, including MTX. Once eligible for subsidy the clinician can prescribe the b/tsDMARD deemed most clinically appropriate.

Objectives:

To determine the patterns of use and reasons for initiation and discontinuation of JAKi in real-world rheumatology practice in Australia.

Methods:

Deidentified clinical data were sourced from the OPAL dataset, which is collected in a custom-built electronic medical record at the time of the consultation1by 94 rheumatologists in Australia, representing one third of Australian clinical rheumatologists. Data from patients >18 years with a diagnosis of RA who commenced a b/tsDMARD between Jan-2007 and Sept-2019 were included in the analysis. Tableau®was used to display data on medication initiation and cessation dates, and reasons for starting and stopping b/tsDMARDs, which is recorded at the time of the decision.

Results:

At Sept 2019, there were 45,317 patients with RA in the data set, with 27% prescribed b/tsDMARDs. Of patients currently on treatment at Sept 2019, 53% were receiving a TNFi and 21% a JAKi, with the remainder receiving tocilizumab, abatacept or rituximab. Of patients who commenced their current treatment after JAKi’s become available in Sept 2015, 46% were treated with a TNFi, and 32% were treated with a JAKi. Tofacitinib (TOF) has been the most prescribed b/tsDMARD since Sept 2015 with 22% of all initiations; however, since baricitinib (BARI) became available in Sept 2018, it has taken over as the preferred JAKi with 24% of new initiations compared to 14% for TOF. From Sept 2018-Sept 2019 etanercept and adalimumab were the most commonly prescribed agents in first line, followed by TOF then BARI; however, BARI was the most prescribed agent in lines 2-6+ (figure 1). The main clinician-listed reason for choice of TOF was MOA in 54%, efficacy compared with alternatives in 30%, mode of administration in 7%, efficacy as monotherapy in 7%, and safety in 1%. BARI was chosen for MOA in 35%, efficacy compared with alternatives in 38%, mode of administration in 12%, efficacy as monotherapy in 12%, and safety in 1%. The main reasons for stopping TOF were lack of efficacy (34%), better alternative (25%) and adverse reaction (13%); those for BARI were lack of efficacy (35%) and adverse reaction (25%) which is consistent with the rates observed in the first 12-months of clinical experience with TOF, and better alternative (12%). Patient non-adherence was listed in 1% and 2% of cessations for TOF and BARI, respectively. 45% of patients discontinuing a JAKi in first line switched to a TNFi in second line, and 40% switched to another JAKi, citing lack of efficacy, adverse reaction, and better alternative as the reason for switching.

Figure 1.

Rank of new initiations by line of therapy (Sept 2018-Sept 2019)

Conclusion:

There has been significant and sustained uptake of JAKi for the management of RA in Australia. MOA and perceived efficacy rate much higher than mode of administration for clinicians when selecting a JAKi. Clinical outcomes and persistence following JAKi cycling requires further investigation.

References:

Littlejohn GO, Tymms KE, Smith T, Griffiths HT. Using big data from real-world Australian rheumatology encounters to enhance clinical care and research. Clin Exp Rheum Nov 2019

Disclosure of Interests:

None declared

Maximizing the use of social and behavioural information from secondary care mental health electronic health records

PURPOSE

The contribution of social and behavioural factors in the development of mental health conditions and treatment effectiveness is widely supported, yet there are weak population level data sources on social and behavioural determinants of mental health. Enriching these data gaps will be crucial to accelerating precision medicine. Some have suggested the broader use of electronic health records (EHR) as a source of non-clinical determinants, although social and behavioural information are not systematically collected metrics in EHRs, internationally.

OBJECTIVE

In this commentary, we highlight the nature and quality of key available structured and unstructured social and behavioural data using a case example of value counts from secondary mental health data available in the UK from the UK Clinical Record Interactive Search (CRIS) database; highlight the methodological challenges in the use of such data; and possible solutions and opportunities involving the use of natural language processing (NLP) of unstructured EHR text.

CONCLUSIONS

Most structured non-clinical data fields within secondary care mental health EHR data have too much missing data for adequate use. The utility of other non-clinical fields reported semi-consistently (e.g., ethnicity and marital status) is entirely dependent on treating them appropriately in analyses, quantifying the many reasons behind missingness in consideration of selection biases. Advancements in NLP offer new opportunities in the exploitation of unstructured text from secondary care EHR data particularly given that clinical notes and attachments are available in large volumes of patients and are more routinely completed by clinicians. Tackling ways to re-use, harmonize, and improve our existing and future secondary care mental health data, leveraging advanced analytics such as NLP is worth the effort in an attempt to fill the data gap on social and behavioural contributors to mental health conditions and will be necessary to fulfill all of the domains needed to inform personalized interventions.

Thermionic microwave gun for terahertz and synchrotron light sources

Conventional thermionic microwave and radio frequency (RF) guns can offer high average beam current, which is important for synchrotron light and terahertz (THz) radiation source facilities, as well as for industrial applications. For example, the Advanced Photon Source at Argonne National Laboratory is a national synchrotron-radiation light source research facility that utilizes thermionic RF guns. However, these existing thermionic guns are bulky, difficult to handle and install, easily detuned, very sensitive to thermal expansion, and due for a major upgrade and replacement. In this paper, we present the design of a new, more stable, and reliable gun with optimized electromagnetic performance, improved thermal engineering, and a more robust cathode mounting technique, which is a critical step to improve the performance of existing and future light sources, industrial accelerators, and electron beam-driven THz sources. We will also present a fabricated gun prototype and show results of high-power and beam tests.

SAXS studies of the thermally-induced fusion of diblock copolymer spheres: formation of hybrid nanoparticles of intermediate size and shape

Dilute dispersions of poly(lauryl methacrylate)-poly(benzyl methacrylate) (PLMA-PBzMA) diblock copolymer spheres (a.k.a. micelles) of differing mean particle diameter were mixed and thermally annealed at 150 °C to produce spherical nanoparticles of intermediate size. The two initial dispersions were prepared via reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate in n-dodecane at 90 °C. Systematic variation of the mean degree of polymerization of the core-forming PBzMA block enabled control over the mean particle diameter: small-angle X-ray scattering (SAXS) analysis indicated that PLMA39-PBzMA97 and PLMA39-PBzMA294 formed well-defined, non-interacting spheres at 25 °C with core diameters of 21 ± 2 nm and 48 ± 5 nm, respectively. When heated separately, both types of nanoparticles regained their original dimensions during a 25-150-25 °C thermal cycle. However, the cores of the smaller nanoparticles became appreciably solvated when annealed at 150 °C, whereas the larger nanoparticles remained virtually non-solvated at this temperature. Moreover, heating caused a significant reduction in mean aggregation number for the PLMA39-PBzMA97 nanoparticles, suggesting their partial dissociation at 150 °C. Binary mixtures of PLMA39-PBzMA97 and PLMA39-PBzMA294 nanoparticles were then studied over a wide range of compositions. For example, annealing a 1.0% w/w equivolume binary mixture led to the formation of a single population of spheres of intermediate mean diameter (36 ± 4 nm). Thus we hypothesize that the individual PLMA39-PBzMA97 chains interact with the larger PLMA39-PBzMA294 nanoparticles to form the hybrid nanoparticles. Time-resolved SAXS studies confirm that the evolution in copolymer morphology occurs on relatively short time scales (within 20 min at 150 °C) and involves weakly anisotropic intermediate species. Moreover, weakly anisotropic nanoparticles can be obtained as a final copolymer morphology over a restricted range of compositions (e.g. for PLMA39-PBzMA97 volume fractions of 0.20-0.35) when heating dilute dispersions of such binary nanoparticle mixtures up to 150 °C. A mechanism involving both chain expulsion/insertion and micelle fusion/fission is proposed to account for these unexpected observations.

Deliberate practice as an educational method for learning to interpret the prepubescent female genital examination

BACKGROUND

Correct interpretation of the prepubescent female genital examination is a critical skill; however, physician skill in this area is limited.

OBJECTIVE

To complement the bedside learning of this examination, we developed a learning platform for the visual diagnosis of the prepubescent female genital examination and examined the amount and rate of skill acquisition.

PARTICIPANTS AND SETTING

Medical students, residents, and fellows and attendings participated in an on-line learning platform.

METHODS

This was a multicenter prospective cross-sectional study. Study participants deliberately practiced 158 prepubescent female genital examination cases hosted on a computer-based learning and assessment platform. Participants assigned the case normal or abnormal; if abnormal, they identified the location of the abnormality and the specific diagnosis. Participants received feedback after every case.

RESULTS

We enrolled 107 participants (26 students, 31 residents, 24 fellows and 26 attendings). Accuracy (95 % CI) increased by 10.3 % (7.8, 12.8), Cohen's d-effect size of 1.17 (1.14, 1.19). The change in specificity was +16.8 (14.1, 19.5) and sensitivity +2.4 (-0.9, 5.6). It took a mean (SD) 46.3 (32.2) minutes to complete cases. There was no difference between learner types with respect to initial (p = 0.2) or final accuracy (p = 0.4) scores.

CONCLUSIONS

This study's learning intervention led to effective and feasible skill improvement. However, while participants improved significantly with normal cases, which has relevance in reducing unnecessary referrals to child protection teams, learning gains were not as evident in abnormal cases. All levels of learners demonstrated a similar performance, emphasizing the need for this education even among experienced clinicians.

Comparison of the Petrifilm Dry Rehydratable Film and Conventional Culture Methods for Enumeration of Yeasts and Molds in Foods: Collaborative Study

A collaborative study was performed involving 18 laboratories and 6 food types to compare 3M Petrifilm yeast and mold count plates with the method described in the U.S. Food and Drug Administration’s Bacteriological Analytical Manual. Four species of mold and 2 species of yeast were used to inoculate the following foods: hot dogs, corn meal, ketchup, orange juice, yogurt, and cake mix. Each collaborator received 15 samples of each food type: 5 low-level inoculations, 5 high- level inoculations, and 5 uninoculated samples. There was no significant difference between the means of the 2 methods for any product or inoculation level. The Petrifilm yeast and mold count plate method for enumeration of yeasts and molds in foods has been adopted first action by AOAC INTERNATIONAL.

Haematobia irritans parasitism of F1 yak × beef cattle (Bos grunniens × Bos taurus) hybrids

The horn fly Haematobia irritans (Diptera: Muscidae) is a blood obligate ectoparasite of bovids that causes annual losses to the U.S. beef cattle industry of over US$1.75 billion. Climate warming, the anthropogenic dispersion of bovids and the cross-breeding of beef cattle with other bovid species may facilitate novel horn fly-host interactions. In particular, hybridizing yaks [Bos grunniens (Artiodactyla: Bovidae)] with beef cows (Bos taurus) for heterosis and carcass improvements may increase the exposure of yak × beef hybrids to horn flies. The present paper reports on the collection of digital images of commingled beef heifers (n = 12) and F1 yak × beef hybrid bovids (heifers, n = 7; steers, n = 5) near Laramie, Wyoming (∼ 2200 m a.s.l.) in 2018. The total numbers of horn flies on beef heifers and F1 yak × beef heifers [mean ± standard error (SE): 88 ± 13 and 70 ± 17, respectively] did not differ significantly; however, F1 yak × beef steers had greater total horn fly abundance (mean ± SE: 159 ± 39) than female bovids. The present report of this experiment is the first such report in the literature and suggests that F1 yak × beef bovids are as susceptible as cattle to horn fly parasitism. Therefore, similar monitoring and treatment practices should be adopted by veterinarians, entomologists and producers.

Impact of dietary protein on postprandial glycaemic control and insulin requirements in Type 1 diabetes: a systematic review

AIM

Postprandial hyperglycaemia is a challenge for people living with Type 1 diabetes. In addition to carbohydrate, dietary protein has been shown to contribute to postprandial glycaemic excursions with recommendations to consider protein when calculating mealtime insulin doses. The aim of this review is to identify and synthesize evidence about the glycaemic impact of dietary protein and insulin requirements for individuals with Type 1 diabetes.

METHODS

A systematic literature search of relevant biomedical databases was performed to identify research on the glycaemic impact of dietary protein when consumed alone, and in combination with other macronutrients in individuals with Type 1 diabetes.

RESULTS

The review included 14 published studies dated from 1992 to 2018, and included studies that researched the impact of protein alone (n = 2) and protein in a mixed meal (n = 12). When protein was consumed alone a glycaemic effect was not seen until ≥ 75 g. In a carbohydrate-containing meal ≥ 12.5 g of protein impacted the postprandial glucose. Inclusion of fat in a high-protein meal enhanced the glycaemic response and further increased insulin requirements. The timing of the glycaemic effect from dietary protein ranged from 90 to 240 min. Studies indicate that the postprandial glycaemic response and insulin requirements for protein are different when protein is consumed alone or with carbohydrate and/or fat.

CONCLUSIONS

This systematic review provides evidence that dietary protein contributes to postprandial glycaemic excursions and insulin requirements. These insights have important implications for the education of people with Type 1 diabetes and highlights the need for more effective insulin dosing strategies for mixed macronutrient meals.

ICRP Publication 141: Occupational Intakes of Radionuclides: Part 4

The 2007 Recommendations (ICRP, 2007) introduced changes that affect the calculation of effective dose, and implied a revision of the dose coefficients for internal exposure, published previously in the Publication 30 series (ICRP, 1979a,b, 1980a, 1981, 1988) and Publication 68 (ICRP, 1994b). In addition, new data are now available that support an update of the radionuclide-specific information given in Publications 54 and 78 (ICRP, 1989a, 1997) for the design of monitoring programmes and retrospective assessment of occupational internal doses. Provision of new biokinetic models, dose coefficients, monitoring methods, and bioassay data was performed by Committee 2 and its task groups. A new series, the Occupational Intakes of Radionuclides (OIR) series, will replace the Publication 30 series and Publications 54, 68, and 78. OIR Part 1 (ICRP, 2015) describes the assessment of internal occupational exposure to radionuclides, biokinetic and dosimetric models, methods of individual and workplace monitoring, and general aspects of retrospective dose assessment. OIR Part 2 (ICRP, 2016), OIR Part 3 (ICRP, 2017), this current publication, and the final publication in the OIR series (OIR Part 5) provide data on individual elements and their radioisotopes, including information on chemical forms encountered in the workplace; a list of principal radioisotopes and their physical half-lives and decay modes; the parameter values of the reference biokinetic models; and data on monitoring techniques for the radioisotopes most commonly encountered in workplaces. Reviews of data on inhalation, ingestion, and systemic biokinetics are also provided for most of the elements. Dosimetric data provided in the printed publications of the OIR series include tables of committed effective dose per intake (Sv per Bq intake) for inhalation and ingestion, tables of committed effective dose per content (Sv per Bq measurement) for inhalation, and graphs of retention and excretion data per Bq intake for inhalation. These data are provided for all absorption types and for the most common isotope(s) of each element. The online electronic files that accompany the OIR series of publications contains a comprehensive set of committed effective and equivalent dose coefficients, committed effective dose per content functions, and reference bioassay functions. Data are provided for inhalation, ingestion, and direct input to blood. This fourth publication in the OIR series provides the above data for the following elements: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), actinium (Ac), protactinium (Pa), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), and fermium (Fm).

Optogenetically-Induced Population Discharge Threshold as a Sensitive Measure of Network Excitability

Network excitability is governed by synaptic efficacy, intrinsic excitability, and the circuitry in which these factors are expressed. The complex interplay between these factors determines how circuits function and, at the extreme, their susceptibility to seizure. We have developed a sensitive, quantitative estimate of network excitability in freely behaving mice using a novel optogenetic intensity-response procedure. Synchronous activation of deep sublayer CA1 pyramidal cells produces abnormal network-wide epileptiform population discharges (PDs) that are nearly indistinguishable from spontaneously-occurring interictal spikes (IISs). By systematically varying light intensity, and therefore the magnitude of the optogenetically-mediated current, we generated intensity-response curves using the probability of PD as the dependent variable. Manipulations known to increase excitability, such as sub-convulsive doses (20 mg/kg) of the chemoconvulsant pentylenetetrazol (PTZ), produced a leftward shift in the curve compared to baseline. The anti-epileptic drug levetiracetam (LEV; 40 mk/kg), in combination with PTZ, produced a rightward shift. Optogenetically-induced PD threshold (oPDT) baselines were stable over time, suggesting the metric is appropriate for within-subject experimental designs with multiple pharmacological manipulations.

P680The clinical value of CMR in the management of Cardio-Oncology patients - a tertiary centre experience

Background

There is increasing awareness of cardiotoxicity arising from cancer treatments. Early diagnosis and treatment is key, to ensure patients receive optimal oncological management. Cardiovascular magnetic resonance (CMR) offers gold standard measurement of cardiac function, alongside tissue characterisation and myocardial perfusion, thereby potentially providing additive value in the context of cardio-oncology.

Purpose

We sought to understand the clinical value of CMR in cardio-oncology at a tertiary cardio-oncology centre.

Methods

We retrospectively reviewed CMR scans requested in cardio-oncology patients at our institution within a ten-month period. We categorised clinical indications and assessed the impact on clinical management using previously-published criteria.

Results

102 CMR studies were requested in 93 cardio-oncology patients (mean age 56 (range 18 to 82), 49% male) between (March to December 2018). 41% of patients had haematological malignancies, 59% solid tumours.

15% of requests were for risk stratification prior to initiation of cancer therapy, 21% for screening for cardio-toxicity in patients currently receiving cardiotoxic agents (3% anthracyclines, 13% HER2 monoclonal antibodies, 4% fluoropyrimidines), 15% for investigation of patients with cardiac complications during cancer treatment, 35% assessment for late effects post cancer treatment, and 14% for cardiac malignancies/ infiltration.

The most common indications for CMR were monitoring of left ventricular ejection fraction (LVEF) in patients where quantification by echocardiography was non-diagnostic or significantly different between imaging studies (39%) and ischaemia assessment including for patients due to receive fluoropyrimidines (26%). Others were aetiology of LV dysfunction/cardiomyopathy (13%) and tissue characterisation (23%), including assessment for cardiac AL amyloid (11 patients), myocarditis (2), cardiac metastases (1), cardiac masses (6), and cardiac iron loading (1).

CMR findings had clinical impact in 61% of patients and assisted in adjudicating a new diagnosis in 29% of patients. 88% of patients were able to continue anthracycline/anti-HER2 therapies based on CMR findings of stable LVEF (93% of whose echocardiograms had suggested reductions). LVEF had reduced significantly in 12% of patients meaning chemotherapy was held/discontinued. 3 patients were recommended to receive non-fluoropyrimidine chemotherapy based on perfusion CMR (pCMR) findings, with one patient permitted to receive capecitabine following normal pCMR.

Conclusion

CMR provides a comprehensive assessment of myocardial structure and function with utility within the context of cardio-oncology for risk stratification pre-chemotherapy, screening for cardiotoxicity during treatment and investigation of cardiac complications of cancer treatment. The additional information derived from CMR generally provides reassurance enabling administration of optimal cancer therapies.

Effect of walking surface, late-cueing, physiological characteristics of aging, and gait parameters on turn style preference in healthy, older adults

Turning while walking is a crucial component of locomotion, often performed on irregular surfaces with little planning time. Turns can be difficult for some older adults due to physiological age-related changes. Two different turning strategies have been identified in the literature. During step turns, which are biomechanically stable, the body rotates about the outside limb, while for spin turns, generally performed with closer foot-to-foot distance, the inside limb is the main pivot point. Turning strategy preferences of older adults under challenging conditions remains unclear. The aim of this study was to determine how turning strategy preference in healthy older adults is modulated by surface features, cueing time, physiological characteristics of aging, and gait parameters. Seventeen healthy older adults (71.5 ± 4.2 years) performed 90° turns for two surfaces (flat, uneven) and two cue conditions (pre-planned, late-cue). Gait parameters were identified from kinematic data. Measures of lower-limb strength, balance, and reaction-time were also recorded. Generalized linear (logistic) regression mixed-effects models examined the effect of (1) surface and cuing, (2) physiological characteristics of ageing, and (3) gait parameters on turn strategy preference. Step turns were preferred when the condition was pre-planned (p < 0.001) (model 1) and when the gait parameters of stride regularity and maximum acceleration decreased (p = 0.010 and p = 0.039, respectively) (model 3). Differences in turn strategy selection under dynamic conditions ought to be evaluated in future fall-risk research and rehabilitation utilizing real-world activity monitoring.

The stabilization effect of the conjoint tendon in reverse total shoulder arthroplasty

BACKGROUND

Numerous factors determine stability of reverse total shoulder arthroplasty. The effect of the conjoint tendon in relation to stability remains unknown. In this biomechanical study, we evaluated the influence of the conjoint tendon on the anterior stability of reverse total shoulder arthroplasty with a hemispherical glenosphere and a glenosphere with 9 mm lateralisation.

METHODS

A reverse total shoulder arthroplasty was implanted in 6 human cadaveric shoulders. The anterior stability was evaluated using a shoulder simulator. Two conditions, intact and dissected conjoint tendon, and 2 component configurations, a hemispherical glenosphere and a glenosphere with 9 mm lateralisation, were tested in each specimen. Testing of anterior stability was performed in 30° and 60° of abduction, with 0° and 30° of external rotation in the glenohumeral joint.

FINDINGS

The conjoint tendon showed a significant influence on the anterior stability with a hemispherical glenosphere in 30° and 60° with neutral rotation (p = 0.028) as well as 30° abduction with 30° (p = 0.028) external rotation. The 9 mm lateralised glenosphere stabilized significantly reverse total shoulder arthroplasty with resected conjoint tendon compared to the hemispherical glenosphere with resected conjoint tendon (p = 0.028).

INTERPRETATION

In a biomechanical setting the conjoint tendon has a stabilizing influence on the anterior stability of the reverse total shoulder arthroplasty with a hemispherical glenosphere in an abducted arm position, but this stabilizing effect was not seen with the lateralised glenosphere. The single influence of the lateralisation of the glenosphere on anterior stability was shown in cases of resected conjoint tendon.

The mechanical loading and muscle activation of four common exercises used in osteoporosis prevention for early postmenopausal women

High impact exercise can reduce postmenopausal bone loss, however stimulus frequency (loading cycles per second) can affect osteogenesis. We aimed to examine the effect of stimulus frequency on the mechanical loading of four common osteoporosis prevention exercises, measuring body acceleration and muscle activation with accelerometry and electromyography (EMG), respectively. Fourteen early postmenopausal women completed randomised countermovement jumps (CMJ), box-drops (BD), heel-drops (HD) and stamp (STP) exercises for continuous and intermittent stimulus frequencies. Sacrum accelerometry and surface electromyography (EMG) of four muscles were recorded. CMJ (mean ± SD: 10.7 ± 4.8 g & 10.0 ± 5.0 g), BD (9.6 ± 4.1 g & 9.5 ± 4.0 g) and HD (7.3 ± 3.8 g & 8.6 ± 4.4 g) conditions generated greater peak acceleration than STP (3.5 ± 1.4 g & 3.6 ± 1.7 g) across continuous and intermittent trials. CMJ and BD generated greater acceleration gradients than STP across continuous and intermittent trials. CMJ generated greater rectus femoris EMG than all other exercises, CMJ and BD generated greater semitendinosus and tibialis anterior EMG than HD across continuous and intermittent trials. CMJ and BD provide greater peak acceleration than STP and remain similar during different stimulus frequencies. CMJ, BD and HD may exceed STP in maintaining postmenopausal bone health.

Genetic diversity and cultivar variants in the NCGR cranberry (Vaccinium macrocarpon Aiton) collection

The American cranberry (Vaccinium macrocarpon) is an endemic domesticated species that has become an economically important commercial fruit crop. The USDA-ARS National Clonal Germplasm Repository (NCGR) houses the national Vaccinium collection, which includes representatives of historical cranberry cultivars and wild-selected germplasm. The objective of this study wasto examine the genotypes of 271 cranberry plants from 77 accessions representing 66 named cultivars using 12 simple-sequence repeats to assess clonal purity and cultivar relatedness. Using principal components analysis and neighbour-joining based on estimated genetic distances between individuals, we identified 64 unique genotypes and observed that intracultivar variants (i.e. subclones) existed in the germplasm collection and in the commercial bogs where some accessions originated. Finally, through a comparison of the genotypes of this study with the previous studies, pedigree analysis and the study of the geographic distribution of cranberry diversity, we identified consensus genotypes for many accessions and cultivars. We highlight the important role that the NCGR collection playsfor ex situ conservation of cranberry germplasm for future breeders and researchers. The NCGR continues to search for historically relevant cultivars absent from the collection in an effort to preserve these genotypes before they are lost and no longer commercially grown.