The development of imaging biomarkers for the diagnosis of human prion disease

Future therapeutic trials in human prion disease will require the use of biomarkers of disease activity such as MRI in order to assess efficacy of treatment. Whilst the development of biomarkers is of importance it is also necessary to be able to understand and interpret what imaging findings characterise at post-mortem and furthermore how they correlate with clinical symptoms. In this thesis I investigate whether both conventional and quantitative imaging parameters can act as biomarkers to predict disease progression in symptomatic patients. I also assess what conventional MRI findings represent on a microstructural level and how imaging findings correlate with clinical symptoms of prion disease such as sleep disturbance. This work is detailed in four projects, the first of which I investigate if abnormalities found on conventional MRI brain scans, PRNP genotype and prion strain can act as predictors of disease progression in patients with the sporadic form of prion disease. I was unable to show that conventional MR brain imaging helps to predict disease progression in this patient group, but I was able to show that codon 129 remains the main predictor of disease progression and strain subtype has an additional effect. In the second project I test the hypothesis that MTR, a quantitative imaging parameter can predict disease progression in symptomatic patients. I found that both on cross-sectional and longitudinal analysis there were significant differences in symptomatic patients and that there was a strong correlation with the MRC Scale score, clinical outcome measure, and MTR value in patients with symptomatic disease which could be used as a clinical biomarker in combination to predict response to therapeutics in future clinical trials. In the third project I focus on investigating the prevalence of sleep disturbance and its association with other features of disease and imaging findings. I found that sleep disturbance was highly prevalent in all forms of prion disease. I also found that there was a significant association found between thalamic signal change seen on MRI scan and sleep symptomatology. In order to capture more data on the diversity of sleep symptoms in this population I constructed the Prion Disease Sleep Questionnaire a bedside screening tool that can be used to both record and monitor the incidence and severity of sleep disturbance. In the final project I assess if specific histopathological findings on post-mortem correlate with cortical imaging abnormalities seen on DWI in patients diagnosed with sporadic CJD. I found that there were significant difference between patients with and without cortical ribboning present on their MRI brain scans those with DWI signal change had more frontal cortex spongiosis than those that didn’t. There was also a modest correlation identified between the 3 histopathological parameters: PrPSc, deposition, gliosis and spongiosis

Some comprehension problems in kindergarten,

Thesis (M.A.)--Boston Universit

Role-model, reoffer, reward: A thematic analysis and TDF mapping of influences on families’ use of evidence-based vegetable feeding practices

Children's vegetable intake is low, despite benefits for immediate and long-term health. Repeatedly reoffering vegetables, role-modelling consumption, and offering non-food rewards effectively increase children's vegetable acceptance and intake. However, a number of barriers prevent families from reoffering previously-rejected vegetables. This study used the Theoretical Domains Framework (TDF) and the COM-B model of behaviour to explore barriers and enablers to reoffering, role-modelling and offering non-food rewards among parents of 2-4-year-old children. Twenty-five semi-structured interviews were conducted, from which eleven core inductive themes were generated: ‘Child factors’, ‘Eating beliefs’, ‘Effectiveness beliefs’, ‘Past experience’, ‘Current family behaviours’, ‘Harms’, ‘Knowledge’, ‘Need for change’, ‘Parent effort’, ‘Parent values’ and ‘Practical issues’. The codes underpinning these themes were inductively mapped to 11 of the 14 TDF domains, and five of the six COM-B components. Previously-reported influences on families' vegetable feeding practices were confirmed, including concerns about child rejection of foods/meals, cost of vegetables, and food waste. Novel findings included some parents' perceptions that these practices are pressurising, and that certain beliefs/knowledge about children's eating behaviour can provide a “protective mindset” that supports families' perseverance with reoffering over time. Future interventions should be tailored to better reflect the diversity of needs and previous experiences of feeding that families have, with some families likely to find that troubleshooting and further signposting is appropriate for their needs while others might benefit from more persuasive and educational approaches. The mapping of codes to the TDF and COM-B will facilitate the identification of appropriate intervention functions and behaviour change techniques when designing new interventions to support families with increasing their children's vegetable intake

Establishing a robust two-step cloning strategy for the generation of cell lines with a high probability of monoclonality

A regulatory requirement for the production of therapeutic proteins from mammalian cells is that the production cell line is clonal, that is, derived from a single progenitor cell. It is therefore standard procedure to include at least one cloning step during the development of a recombinant cell line for therapeutic protein production. Numerous techniques can be employed for cloning cell lines, but regardless of the cloning method used there should be appropriate evidence to support that the method is fit for purpose. A point highlighted by the increasing interest from regulatory bodies regarding the cloning method used and the probability of monoclonality (P(monoclonality)) achieved during cell line development (CLD). FUJIFILM Diosynth Biotechnologies have thoroughly considered the cloning approach used during CLD: A two-step cloning strategy employed which combines the ClonePix™ as a cloning and screening tool followed by a second cloning step using the industrially accepted method of limiting dilution cloning will be discussed. A collaboration with statisticians led to the development of a method to estimate the resulting P(monoclonality) of cell lines generated using the ClonePix™ and experimental data to support this statistical method was generated, thereby ensuring that the ClonePix™ cloning step is robust. We will highlight the challenges of using the ClonePix™ for a single round of cloning and the advantages of combining it with a second cloning step. We will demonstrate how we achieve a minimum probability of monoclonality of ≥99.78% and typically achieve a P(monoclonality) of 99.9% using a two-step cloning strategy

Accelerated Partial Breast Irradiation: Using the CyberKnife as the Radiation Delivery Platform in the Treatment of Early Breast Cancer

We evaluate the CyberKnife (Accuray Incorporated, Sunnyvale, CA, USA) for non-invasive delivery of accelerated partial breast irradiation (APBI) in early breast cancer patients. Between 6/2009 and 5/2011, nine patients were treated with CyberKnife APBI. Normal tissue constraints were imposed as outlined in the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 (NSABP/RTOG) Protocol (Vicini and White, 2007). Patients received a total dose of 30 Gy in five fractions (group 1, n = 2) or 34 Gy in 10 fractions (group 2, n = 7) delivered to the planning treatment volume (PTV) defined as the clinical target volume (CTV) +2 mm. The CTV was defined as either the lumpectomy cavity plus 10 mm (n = 2) or 15 mm (n = 7). The cavity was defined by a T2-weighted non-contrast breast MRI fused to a planning non-contrast thoracic CT. The CyberKnife Synchrony system tracked gold fiducials sutured into the cavity wall during lumpectomy. Treatments started 4–5 weeks after lumpectomy. The mean PTV was 100 cm3 (range, 92–108 cm3) and 105 cm3 (range, 49–241 cm3) and the mean PTV isodose prescription line was 70% for groups 1 and 2, respectively. The mean percent of whole breast reference volume receiving 100 and 50% of the dose (V100 and V50) for group 1 was 11% (range, 8–13%) and 23% (range, 16–30%) and for group 2 was 11% (range, 7–14%) and 26% (range, 21–35.0%), respectively. At a median 7 months follow-up (range, 4–26 months), no acute toxicities were seen. Acute cosmetic outcomes were excellent or good in all patients; for those patients with more than 12 months follow-up the late cosmesis outcomes were excellent or good. In conclusion, the lack of observable acute side effects and current excellent/good cosmetic outcomes is promising. We believe this suggests the CyberKnife is a suitable non-invasive radiation platform for delivering APBI with achievable normal tissue constraints

Anthropometric study to update minimum aircraft seating standards

This study was initiated by the Joint Aviation Authorities (JAA) under UK Civil Aviation Authority funding. The study was undertaken against a background trend of generally increasing body dimensions within the European population. This trend, when combined with an increasing number of longer duration flights and high density seating, prompted the need for a wide-ranging review of published anthropometric data that would guide JAA when considering the need for any regulation in this area. It should be noted that this report concentrates on the safety issues associated with seating arrangements. The specific aim is to ensure that seating standards are such that passengers would be able to quickly evacuate an aircraft in the event of an emergency. Thus, the study considers seating accommodation against expected population body dimensions. Software modelling has been used to make an initial assessment of the relationship between seating dimensions and evacuation difficulties. The health implications of aircraft seating are also considered. However, the comfort aspects of aircraft seating did not form part of the research study

Evidence of blood stage efficacy with a virosomal malaria vaccine in a Phase IIa clinical trial

Background Previous research indicates that a combination vaccine targeting different stages of the malaria life cycle is likely to provide the most effective malaria vaccine. This trial was the first to combine two existing vaccination strategies to produce a vaccine that induces immune responses to both the pre-erythrocytic and blood stages of the P. falciparum life cycle. Methods This was a Phase I/IIa study of a new combination malaria vaccine FFM ME-TRAP+PEV3A. PEV3A includes peptides from both the pre-erythrocytic circumsporozoite protein and the blood-stage antigen AMA-1. This study was conducted at the Centre for Clinical Vaccinology and Tropical Medicine, University of Oxford, Oxford, UK. The participants were healthy, malaria naïve volunteers, from Oxford. The interventions were vaccination with PEV3A alone, or PEV3A+FFM ME-TRAP. The main outcome measure was protection from malaria in a sporozoite challenge model. Other outcomes included measures of parasite specific immune responses induced by either vaccine; and safety, assessed by collection of adverse event data. Results We observed evidence of blood stage immunity in PEV3A vaccinated volunteers, but no volunteers were completely protected from malaria. PEV3A induced high antibody titres, and antibodies bound parasites in immunofluorescence assays. Moreover, we observed boosting of the vaccine-induced immune response by sporozoite challenge. Immune responses induced by FFM ME-TRAP were unexpectedly low. The vaccines were safe, with comparable side effect profiles to previous trials. Although there was no sterile protection two major observations support an effect of the vaccine-induced response on blood stage parasites: (i) Lower rates of parasite growth were observed in volunteers vaccinated with PEV3A compared to unvaccinated controls (p = 0.012), and this was reflected in the PCR results from PEV3A vaccinated volunteers. These showed early control of parasitaemia by some volunteers in this group. One volunteer, who received PEV3A alone, was diagnosed very late, on day 20 compared to an average of 11.8 days in unvaccinated controls. (ii). Morphologically abnormal parasites were present in the blood of all (n = 24) PEV3A vaccinated volunteers, and in only 2/6 controls (p = 0.001). We describe evidence of vaccine-induced blood stage efficacy for the first time in a sporozoite challenge study

Students being set up to make mistakes in class through an error-eliciting task

In order for students to develop a better understanding and the skills to question future work, a session is introduced into a teaching workshop which sets students up to make common mistakes within a topic are more often made by blindly following procedural methods. The students’ views on these mistakes and how they found the error-eliciting task were gained through focus groups on the day of the activity. Factors such as knowing whether they had the right answer and the amount of staff involvement were discussed. In a follow-on focus group two weeks after the session, there were indications that the session had an impact on how they worked generally as there was more discussion within class and a shift in views about making mistakes

The Effect of Low-Processing Temperature on the Physicochemical and Mechanical Properties of Bovine Hydroxyapatite Bone Substitutes

Bovine bone grafts (BBX) require protein removal as part of the manufacturing process to reduce antigenicity and, in consequence, to be safely used in humans. Deproteinisation may have direct effects on the characteristics of the bone material and on in vivo material performance. This research aimed to comprehensively study the physicochemical and mechanical properties of BBX processed at low deproteinisation processing temperatures. Cubes of bovine bone (8 mm3) were treated with temperatures between 100 °C and 220 °C at 30 °C intervals and with pressures ranging from 1.01 to 24.58 Bar. The samples were characterised topographically and mechanically using scanning electron microscopy (SEM), atomic force microscopy (AFM), and uniaxial bending tests. The organic content and the chemical composition were determined using thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) and FTIR were also used to quantitatively determine the specimen crystallinity. Increasing temperature/pressure was associated with decreasing protein levels and compressive strength and increasing surface irregularities and crystallinity. The findings suggest that low-temperature processed bone is likely to exhibit a rapid in vivo degradation rate. The deproteinisation temperature can be adjusted to tailor the graft properties for specific applications