Unique T-cell Sub-Population Shifts after SBPT and Nivolumab in Platinum Refractory HNC: Biomarker Correlates from ROR1771

PURPOSE/OBJECTIVE(S)

ROR1771 was a clinical trial investigating the use of stereotactic body proton radiotherapy (SBPT) and nivolumab in recurrent platinum refractory head and neck squamous cell carcinoma (HNSCC). The planned analysis of T-cell subpopulation and biomarker response is herein presented.

MATERIALS/METHODS

Patients with metastatic histologically confirmed HNSCC from any primary site received 2 cycles of nivolumab followed by SBPT to 1-2 selected target lesion(s) (hilar/lung: 8 of 12 patients), followed by maintenance nivolumab. Peripheral blood mononuclear cells were isolated pre-/post-treatment. Flow cytometry identified T-cell subpopulations. Single Cell 5' Gene Expression (GEX) and V(D)J T Cell Receptor libraries were prepared using Single Cell Immune Profiling. Seurat (v4.1.1) was used to identify cell type clusters, and differential expression post-filtration was evaluated using the Wilcoxon Rank Sum test.

RESULTS

A total of 12 patients were eligible for analysis, with one alive at time of analysis, 52 months from start of treatment. Median overall survival here was 12.5 months vs. 7.5-months on CheckMate 141. SBPT ranged from 35-50 Gy. Sequential changes in T-cell populations from baseline were noted with initiation of nivolumab, driving decrease in tumor-reactive (TTR; CD11ahighPD1+CD8+), central memory (TCM; CCR7+CD45RA-), and effector T-cells (TEF; CCR7-CD45RA-). TTR and TCM increased following SBPT, with greatest increase (3.5x TTR and 5.2x TCM) in the surviving patient. An average of 68 genes with significant differential expression between timepoints (p<0.0001) demonstrated RNA gene expression changes across all cell subtypes, including ribosomal (RPL and RPS) genes, ACTB, FTL, MALAT1, and others. This averaged 113 genes across all timepoints in the surviving patient, with peak following nivolumab induction. On T-cell receptor (TCR) analysis of this patient, the predominant clonotype diversity changed substantially following nivolumab. Following SBPT, clonotype diversity again changed to include a milieu seen neither at baseline nor with nivolumab alone. These TCRs persisted for approximately 2 weeks following SBPT before returning to resemble the nivolumab-induced TCR diversity alone, coinciding with disease recurrence.

CONCLUSION

ROR1771 demonstrated overall survival favorably comparable to CheckMate 141. Biomarker analysis of peripheral blood samples demonstrated significant shifts in T-cell subpopulations and underlying gene expression to nivolumab and then to SBPT administration. SBPT to a target lesion changed TCR clonotypes within the peripheral blood beyond those seen with nivolumab administration, with fading of these TCR clonotypes coinciding with recurrence. SBPT in combination with nivolumab may drive systemic immunologic change above that induced by nivolumab alone and warrants further investigation.

Using robotics to move a neurosurgeon's hands to the tip of their endoscope

A major advantage of surgical robots is that they can reduce the invasiveness of a procedure by enabling the clinician to manipulate tools as they would in open surgery but through small incisions in the body. Neurosurgery has yet to benefit from this advantage. Although clinical robots are available for the least invasive neurosurgical procedures, such as guiding electrode insertion, the most invasive brain surgeries, such as tumor resection, are still performed as open manual procedures. To investigate whether robotics could reduce the invasiveness of major brain surgeries while still providing the manipulation capabilities of open surgery, we created a two-armed joystick-controlled endoscopic robot. To evaluate the efficacy of this robot, we developed a set of neurosurgical skill tasks patterned after the steps of brain tumor resection. We also created a patient-derived brain model for pineal tumors, which are located in the center of the brain and are normally removed by open surgery. In comparison, testing with existing manual endoscopic instrumentation, we found that the robot provided access to a much larger working volume at the trocar tip and enabled bimanual tasks without compression of brain tissue adjacent to the trocar. Furthermore, many tasks could be completed faster with the robot. These results suggest that robotics has the potential to substantially reduce the invasiveness of brain surgery by enabling certain procedures currently performed as open surgery to be converted to endoscopic interventions.

Robotic Instruments Inside the MRI Bore: Key Concepts and Evolving Paradigms in Imaging-enhanced Cranial Neurosurgery

Intraoperative MRI has been increasingly used to robotically deliver electrodes and catheters into the human brain using a linear trajectory with great clinical success. Current cranial MR guided robotics do not allow for continuous real-time imaging during the procedure because most surgical instruments are not MR-conditional. MRI guided robotic cranial surgery can achieve its full potential if all the traditional advantages of robotics (such as tremor-filtering, precision motion scaling, etc.) can be incorporated with the neurosurgeon physically present in the MRI bore or working remotely through controlled robotic arms. The technological limitations of design optimization, choice of sensing, kinematic modeling, physical constraints, and real-time control had hampered early developments in this emerging field, but continued research and development in these areas over time has granted neurosurgeons far greater confidence in using cranial robotic techniques. This article elucidates the role of MR-guided robotic procedures using clinical devices like NeuroBlate and Clearpoint that have several thousands of cases operated in a "linear cranial trajectory" and planned clinical trials, such as LAANTERN for MR guided robotics in cranial neurosurgery using LITT and MR-guided putaminal delivery of AAV2 GDNF in Parkinson's disease. The next logical improvisation would be a steerable curvilinear trajectory in cranial robotics with added DOFs and distal tip dexterity to the neurosurgical tools. Similarly, the novel concept of robotic actuators that are powered, imaged, and controlled by the MRI itself is discussed in this article, with its potential for seamless cranial neurosurgery.

Management of dental emergencies amongst Australian general medical practitioners - A case-vignette study

BACKGROUND

In Australia, because of inequity in dental service accessibility and affordability, patients can see general medical practitioners (GPs) for acute dental conditions.

METHODS

This cross-sectional study consisted of surveys distributed to the board registered GPs practising in Australia. The main outcome measures included statistical analysis of GPs managing different dental emergency scenarios and their confidence and expectations in managing dental emergencies.

RESULTS

A total of 425 GPs participated in the study. The sample primarily consisted of GPs practising in metropolitan clinics (n = 315). Most participants reported that they would refer to the dentist for mobilized tooth (n = 402). There was a negative correlation between GPs with 5-29 years of experience and traumatized tooth management (P < 0.05). GPs aged between 40 and 49 years were more inclined to treat patients with mobilized teeth [Multivariate (MV): 0.42(0.09-0.74)]. However, GPs with 0-5 years of experience were less likely to manage patients with dental abscess [MV: -0.52(-0.80 to -0.24)].

CONCLUSION

Most GPs referred dental emergencies to dentists. GP management of dental emergencies were predominantly palliative. Therefore, opportunities for collaborative practice models amongst GPs and dentists may be needed to bridge the gap in the regional and remote locations.

A geometrically adaptable heart valve replacement

Congenital heart valve disease has life-threatening consequences that warrant early valve replacement; however, the development of a growth-accommodating prosthetic valve has remained elusive. Thousands of children continue to face multiple high-risk open-heart operations to replace valves that they have outgrown. Here, we demonstrate a biomimetic prosthetic valve that is geometrically adaptable to accommodate somatic growth and structural asymmetries within the heart. Inspired by the human venous valve, whose geometry is optimized to preserve functionality across a wide range of constantly varying volume loads and diameters, our balloon-expandable synthetic bileaflet valve analog exhibits similar adaptability to dimensional and shape changes. Benchtop and acute in vivo experiments validated design functionality, and in vivo survival studies in growing sheep demonstrated that mechanical valve expansion accommodated growth. As illustrated in this work, dynamic size adaptability with preservation of unidirectional flow in prosthetic valves thus offers a paradigm shift in the treatment of heart valve disease.

Secondary non-invasive prenatal screening for fetal trisomy: an effectiveness study in a public health setting

OBJECTIVE

To evaluate the effectiveness of secondary screening using non-invasive prenatal testing (NIPT) in a routine NHS setting including test performance, turn-around times (TATs) and no-call (failure to obtain result) rates. To examine the influence of maternal and fetal characteristics on test performance.

DESIGN

Retrospective cohort.

SETTING

London teaching hospital.

SAMPLE

A total of 8651 pregnancies undergoing screening for fetal trisomy using NIPT provided by an NHS cell-free DNA screening laboratory - the SAFE laboratory.

METHODS

Screening test evaluation and TATs. Univariate and multivariate logistic regression analysis to identify significant predictors of no-call results and reported by low fetal fraction (<2%), very high fetal fraction (>40%) and processing failure.

MAIN OUTCOME MEASURES

Test performance, TATs and no-call rates, factors affecting no-call results.

RESULTS

Average TAT was 4.0 days (95% CI 4.0-4.2 days). Test sensitivities for trisomies 21 and 13/18 were 98.9% (95% CI 95.9-99.9%) and 90.4% (95% CI 80.0-96.8%), respectively. The overall no-call rate was 32/8651 (0.37%, 95% CI 0.26-0.52%). The overall risk of a no-call result was influenced by gestational age, dichorionic twin pregnancy, history of malignancy and pregnancies affected by trisomy 13/18, but not by maternal weight or use of low-molecular-weight heparin.

CONCLUSIONS

High-throughput NIPT can be effectively embedded into a public health NHS setting. TATs of 4 days and no-calls of <0.5% were well within clinically desirable tolerances. Gestational age, maternal weight, assisted reproductive techniques, use of low-molecular-weight heparin and past history of malignancy did not have major impacts on test no-call rates and should not constitute reasons for withholding the option of NIPT from women.

TWEETABLE ABSTRACT

Turn-around times of 4 days, no-call (test failure) rates of 0.37% and highly accurate NIPT can be successfully embedded in the NHS.

Is it safe for extended-role radiographers to measure migration percentage in children with cerebral palsy?

INTRODUCTION

In the surveillance of children with cerebral palsy, the measurement of migration percentage is used to identify children at risk of hip dislocation. Early identification of children at risk facilitates early intervention with less invasive surgical procedures to prevent further deterioration. The aim of this study is to evaluate the safety of the measurements of migration percentage for surveillance in cerebral palsy by extended-role radiographers by evaluating the reliability and validity of measurements performed by these professionals.

METHODS

A sample of thirty pelvic x-rays were selected from the local cerebral palsy database. A range of hip displacement was selected including some challenging borderline x-rays. All ten extended-role radiographers completed measurements using TraumaCAD which were repeated at a minimum of 4 weeks. Inter-rater and intra-rater reliability was calculated using intraclass correlation coefficients. The accuracy and safety of the system was evaluated by converting measurements into referral categories (red, amber or green) and cohen's kappa was calculated when categories were compared to measurements to orthopaedic surgeon RESULTS: The inter-rater reliability between radiographers was 0.938 (95% CI 0.914-0.991). The intra-rater reliability was 0.941 (95% CI 0.931-0.949). The percentage agreement was 94.8% for green, 93.8% for amber and 98.2% for red hips. The weighted kappa value was 0.923 (95% CI 0.889-0.957).

CONCLUSION

The reliability and accuracy of radiographer measurement of migration percentage is excellent. It is safe for radiographers to calculate the migration percentage using semi-automated software for the surveillance of children with cerebral palsy.

IMPLICATIONS FOR PRACTICE

We recommend the measurement of migration percentage may be performed by extended-role radiographers to deliver accurate and reliable measurements for use in cerebral palsy surveillance.

Autonomous Robotic Intracardiac Catheter Navigation Using Haptic Vision

While all minimally invasive procedures involve navigating from a small incision in the skin to the site of the intervention, it has not been previously demonstrated how this can be done autonomously. To show that autonomous navigation is possible, we investigated it in the hardest place to do it - inside the beating heart. We created a robotic catheter that can navigate through the blood-filled heart using wall-following algorithms inspired by positively thigmotactic animals. The catheter employs haptic vision, a hybrid sense using imaging for both touch-based surface identification and force sensing, to accomplish wall following inside the blood-filled heart. Through in vivo animal experiments, we demonstrate that the performance of an autonomously-controlled robotic catheter rivals that of an experienced clinician. Autonomous navigation is a fundamental capability on which more sophisticated levels of autonomy can be built, e.g., to perform a procedure. Similar to the role of automation in fighter aircraft, such capabilities can free the clinician to focus on the most critical aspects of the procedure while providing precise and repeatable tool motions independent of operator experience and fatigue.

Optically-guided instrument for transapical beating-heart delivery of artificial mitral chordae tendineae

OBJECTIVE

We sought to develop an instrument that would enable the delivery of artificial chordae tendineae (ACT) using optical visualization of the leaflet inside the beating heart.

METHODS

A delivery instrument was developed together with an ACT anchor system. The instrument incorporates an optically clear silicone grasping surface in which are embedded a camera and LED for direct leaflet visualization during localization, grasping, and chordal delivery. ACTs, comprised of T-shaped anchors and an expanded polytetrafluoroethylene chordae, were fabricated to enable testing in a porcine model. Ex vivo experiments were used to measure the anchor tear-out force from the mitral leaflets. In vivo experiments were performed in which the mitral leaflets were accessed transapically using only optical guidance and ACTs were deployed in the posterior and anterior leaflets (P2 and A2 segments).

RESULTS

In 5 porcine ex vivo experiments, the mean force required to tear the anchors from the leaflets was 3.8 ± 1.2 N. In 5 porcine in vivo nonsurvival procedures, 14 ACTs were successfully placed in the leaflets (9 in P2 and 5 in A2). ACT implantation took an average of 3.22 ± 0.83 minutes from entry to exit through the apex.

CONCLUSIONS

Optical visualization of the mitral leaflet during chordal placement is feasible and provides direct feedback to the operator throughout the deployment sequence. This enables visual confirmation of the targeted leaflet location, distance from the free edge, and successful deployment of the chordal anchor. Further studies are needed to refine and assess the device for clinical use.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Cardioscopically Guided Beating Heart Surgery: Paravalvular Leak Repair

PURPOSE

There remains a paucity of direct visualization techniques for beating-heart intracardiac procedures. To address this need, we evaluated a novel cardioscope in the context of aortic paravalvular leaks (PVLs) localization and closure.

DESCRIPTION

A porcine aortic PVL model was created using a custom-made bioprosthetic valve, and PVL presence was verified by epicardial echocardiography. Transapical delivery of occlusion devices guided solely by cardioscopy was attempted 13 times in a total of three pigs. Device retrieval after release was attempted six times. Echocardiography, morphologic evaluation, and delivery time were used to assess results.

EVALUATION

Cardioscopic imaging enabled localization of PVLs via visualization of regurgitant jet flow in a paravalvular channel at the base of the prosthetic aortic valve. Occluders were successfully placed in 11 of 13 attempts (84.6%), taking on average 3:03 ± 1:34 min. Devices were cardioscopically removed successfully in three of six attempts (50%), taking 3:41 ± 1:46 min. No damage to the ventricle or annulus was observed at necropsy.

CONCLUSIONS

Cardioscopy can facilitate intracardiac interventions by providing direct visualization of anatomic structures inside the blood-filled, beating-heart model.

A multiport MR-compatible neuroendoscope: spanning the gap between rigid and flexible scopes

OBJECTIVE Rigid endoscopes enable minimally invasive access to the ventricular system; however, the operative field is limited to the instrument tip, necessitating rotation of the entire instrument and causing consequent tissue compression while reaching around corners. Although flexible endoscopes offer tip steerability to address this limitation, they are more difficult to control and provide fewer and smaller working channels. A middle ground between these instruments-a rigid endoscope that possesses multiple instrument ports (for example, one at the tip and one on the side)-is proposed in this article, and a prototype device is evaluated in the context of a third ventricular colloid cyst resection combined with septostomy. METHODS A prototype neuroendoscope was designed and fabricated to include 2 optical ports, one located at the instrument tip and one located laterally. Each optical port includes its own complementary metal-oxide semiconductor (CMOS) chip camera, light-emitting diode (LED) illumination, and working channels. The tip port incorporates a clear silicone optical window that provides 2 additional features. First, for enhanced safety during tool insertion, instruments can be initially seen inside the window before they extend from the scope tip. Second, the compliant tip can be pressed against tissue to enable visualization even in a blood-filled field. These capabilities were tested in fresh porcine brains. The image quality of the multiport endoscope was evaluated using test targets positioned at clinically relevant distances from each imaging port, comparing it with those of clinical rigid and flexible neuroendoscopes. Human cadaver testing was used to demonstrate third ventricular colloid cyst phantom resection through the tip port and a septostomy performed through the lateral port. To extend its utility in the treatment of periventricular tumors using MR-guided laser therapy, the device was designed to be MR compatible. Its functionality and compatibility inside a 3-T clinical scanner were also tested in a brain from a freshly euthanized female pig. RESULTS Testing in porcine brains confirmed the multiport endoscope's ability to visualize tissue in a blood-filled field and to operate inside a 3-T MRI scanner. Cadaver testing confirmed the device's utility in operating through both of its ports and performing combined third ventricular colloid cyst resection and septostomy with an endoscope rotation of less than 5°. CONCLUSIONS The proposed design provides freedom in selecting both the number and orientation of imaging and instrument ports, which can be customized for each ventricular pathological entity. The lightweight, easily manipulated device can provide added steerability while reducing the potential for the serious brain distortion that happens with rigid endoscope navigation. This capability would be particularly valuable in treating hydrocephalus, both primary and secondary (due to tumors, cysts, and so forth). Magnetic resonance compatibility can aid in endoscope-assisted ventricular aqueductal plasty and stenting, the management of multiloculated complex hydrocephalus, and postinflammatory hydrocephalus in which scarring obscures the ventricular anatomy.

Abstract P2-09-05: 12 years' median follow up (MFU) of BIG 1-98: Adjuvant letrozole, tamoxifen and their sequence for postmenopausal women with endocrine responsive early breast cancer

Background

The Breast International Group (BIG) 1-98 study is a randomized, phase 3, double-blind trial that compared five yrs of adjuvant treatment with letrozole, tamoxifen, or their sequence in postmenopausal women with hormone-receptor–positive early breast cancer. The study is conducted by the International Breast Cancer Study Group (IBCSG) on behalf of BIG. 8010 patients (pts) were enrolled between March 1998 and May 2003, and first results demonstrating a significant DFS benefit favoring letrozole compared with tamoxifen were reported in 2005 at 25.8 months' MFU. Subsequent updates showed continuing DFS benefit and updated results published in 2011 at 8.1 yrs' MFU showed OS benefit. Industry-sponsorship of the original BIG 1-98 ended in 2010; IBCSG launched an observational, non-interventional long-term follow-up study (BIG 1-98 LTFU) to collect survival, disease status and adverse events for an additional 5 yrs. We report results from BIG 1-98 LTFU at 12 yrs' MFU.

Methods

The original trial includes the 8010 patients enrolled. The potential BIG 1-98 LTFU cohort consisted of 148 academic medical centers with a maximum of 6843 pts who were alive and continuing follow-up when the original study ended. Response bias was addressed using weighting class adjustments estimated using multivariable logistic regression. Unadjusted incidence rates are reported here per 1000 pt-yrs with 95% Poisson confidence intervals. An updated abstract will include adjusted incidence rates, as well as estimates of OS and DFS based on a weighted Kaplan-Meier approach. The database will close in July 2016.

Results

As of May 2016, 81 centers participated in the BIG 1-98 LTFU study, contributing data from approximately 3900 pts (57%) and extending MFU to 12 yrs. Compared with the potential cohort of 6843 pts, the ~3900 in the LTFU analytic cohort were more likely to be under age 65 yrs at enrollment, have node-positive disease, and have tumors that were &lt; 2 cm, PgR positive (≥1%), and with no evidence of peritumoral vascular invasion. Extended adjuvant endocrine therapy for primary BC was continued in 2% of pts. Unadjusted incidence estimates of myocardial infarction increased during LTFU, while incidence of thromboembolic events and osteoporosis decreased (Table). Variations in incidence rates were noted depending on recording mechanism (e.g. registry, clinic visit, telephone, information from family).

 Unadjusted Incidence Rate/1000 pt-yrs (95% CI)Adverse EventDuring original studyDuring LTFUMyocardial Infarction1.7 (1.4-2.0)3.5 (2.7-4.5)Thromboembolic event6.0 (5.4-6.6)2.5 (1.8-3.3)Osteoporosis23.6 (22.5-24.9)18.2 (16.3-20.3)Bone fractures17.2 (16.2-18.3)15.0 (13.2-16.9)

Overall 1845 deaths were reported; the unadjusted incidence of death was lower in the original study compared with during LTFU (21.9 vs. 26.6/1000 pt-yrs); incidence remained relatively stable for pts assigned to tamoxifen (24.9 vs. 25.2/1000 pt-yrs), and increased for pts assigned to letrozole (22.0 vs. 27.1/1000 pt-yrs).

Conclusions

The BIG 1-98 LTFU study has been successfully conducted. The additional data from the BIG 1-98 LTFU study provides important long-term clinical information about OS, DFS and adverse events.

Citation Format: Thürlimann B, Giobbie-Hurder A, Colleoni M, Jensen M-B, Ejlertsen B, de Azambuja E, Neven P, Láng I, Gladieff L, Bonnefoi H, Harvey VJ, Spazzapan S, Tondini C, Price K, Piccart-Gebhart M, Regan MM, Gelber RD, Coates AS, Goldhirsch A. 12 years' median follow up (MFU) of BIG 1-98: Adjuvant letrozole, tamoxifen and their sequence for postmenopausal women with endocrine responsive early breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-09-05.

Feeling angry about current health status: using a population survey to determine the association with demographic, health and social factors

BACKGROUND

Feeling angry about their health status may influence disease progression in individuals, creating a greater burden on the health care system. Identifying associations between different variables and feeling angry about health status may assist health professionals to improve health outcomes. This study used path analysis to explore findings from a population-based survey, informed by qualitative descriptions obtained from focus groups, to determine the prevalence of health-related anger within the community and variables associated with reporting health-related anger.

METHODS

A population-based Computer Assisted Telephone Interview (CATI) survey of 3003 randomly selected adults Australia-wide was conducted to examine the prevalence of health-related anger. A wide range of other covariates were included in the survey. Multivariable logistic regression and path analysis were undertaken to identify the relationships between different variables associated with feeling angry about the health status of people, to explore the direction of these associations and as a consequence of the results, consider implications for health service use and delivery.

RESULTS

Overall, 18.5 % of the population reported feeling angry about their health "some of the time", "most of the time" or "all of the time". People who felt angry about their health were more likely to have a severe health condition, at least one chronic condition, high psychological distress, fair to poor health status, and needed to adjust their daily lives because of a health condition. Having a tertiary level education was protective. Receiving some form of social support, usually from a support group, and not always doing as advised by a doctor, were also associated with a higher likelihood of being angry about their health.

CONCLUSIONS

People living with significant health problems are more likely to feel angry about their health. The path between illness and anger is, however, complex. Further research is needed to understand the extent that feeling angry influences the progression of health problems and, if necessary, how to minimise this progression. What also needs examining is whether identifying people who feel angry in the general population could be a predictor of persons most likely to develop significant health problems.

Design and development of magnetorheological fluid-based passive actuator

We present the design and experimental validation of a magnetorheological (MR) fluid-based passive actuator for tele-robotic bone biopsy procedures. With Finite Element Method Magnet (FEMM) software, the required uniform magnetic field circuit design was simulated. An 1100 turn 24 AWG copper wire coil wrapped around a magnetic core was used to create a magnetic field. The field strength was measured with a Hall effect sensor, and compared to the simulation. The maximum magnetic field flux produced by a constant current of 1.4 A was 0.2 T, similar to the simulation results. A series of quasi-static experiments were conducted to characterize the forces generated by the MR fluid-based actuator under various currents up to 12 N. An analytical model was developed to validate the measurements from the passive actuator.