NON-INVASIVE MEASUREMENT OF OXIDATIVE STRESS IN SENIOR AND EXERCISING HORSES

The published data regarding oxidative stress in horses is generally concerned with blood and muscle samples. The aim of this thesis was to use non-invasive markers as a novel approach to investigate cellular stress in performance and senior horses. In addition, urine was analysed using IH NMR spectroscopy and renal insult during ageing and exercise was investigated using urinary N-acetyl-beta-D-glucosaminidase (NAG) activity. The results demonstrated that urinary thiobarbituric acid reactive substances (TBARS) in horses could be measured using a method adapted from Vagi (1976) and were significantly decreased following supplementation with antioxidants in the form of dandelion and milk thistle (p<O.05). Urinary TBARS were seen to decrease in horses supplemented with vitamin E at a level of 4mglkg bodyweight, but subsequently were unaffected in horses performing a sub-maximal exercise test on a treadmill when supplemented with vitamin E at a level of 3 mg/kg bodyweight. Urinary TBARS were seen to increase with age (P<O.05), consistent with increased lipid peroxidation in senior horses. Analysis using 1 H NMR spectroscopy revealed higher levels of aromatic amino acids in the urine of senior horses (p<O.05) and proteinuria quantification using the biuret assay demonstrated increased total proteinuria in the urine of senior horses compared to young horses (p<O.05). This indicated that subtle changes in renal, hepatic and endocrine functions may be evident in senior horses. TBARS in equine sweat could be measured using a method adapted from Vagi (1976) and were significantly decreased in horses performing a sub-maximal exercise test on a treadmill, following vitamin E supplementation (p<O.05). In addition, free radical scavenging activity of equine saliva could be measured using a method adapted from Atsumi et al (1999). Urinary NAG activity proved to be difficult to measure in the horse and may require further investigation to establish its potential use as a marker of renal insult in horses

BHPR research: qualitative1. Complex reasoning determines patients' perception of outcome following foot surgery in rheumatoid arhtritis

Background: Foot surgery is common in patients with RA but research into surgical outcomes is limited and conceptually flawed as current outcome measures lack face validity: to date no one has asked patients what is important to them. This study aimed to determine which factors are important to patients when evaluating the success of foot surgery in RA Methods: Semi structured interviews of RA patients who had undergone foot surgery were conducted and transcribed verbatim. Thematic analysis of interviews was conducted to explore issues that were important to patients. Results: 11 RA patients (9 ♂, mean age 59, dis dur = 22yrs, mean of 3 yrs post op) with mixed experiences of foot surgery were interviewed. Patients interpreted outcome in respect to a multitude of factors, frequently positive change in one aspect contrasted with negative opinions about another. Overall, four major themes emerged. Function: Functional ability & participation in valued activities were very important to patients. Walking ability was a key concern but patients interpreted levels of activity in light of other aspects of their disease, reflecting on change in functional ability more than overall level. Positive feelings of improved mobility were often moderated by negative self perception ("I mean, I still walk like a waddling duck”). Appearance: Appearance was important to almost all patients but perhaps the most complex theme of all. Physical appearance, foot shape, and footwear were closely interlinked, yet patients saw these as distinct separate concepts. Patients need to legitimize these feelings was clear and they frequently entered into a defensive repertoire ("it's not cosmetic surgery; it's something that's more important than that, you know?”). Clinician opinion: Surgeons' post operative evaluation of the procedure was very influential. The impact of this appraisal continued to affect patients' lasting impression irrespective of how the outcome compared to their initial goals ("when he'd done it ... he said that hasn't worked as good as he'd wanted to ... but the pain has gone”). Pain: Whilst pain was important to almost all patients, it appeared to be less important than the other themes. Pain was predominately raised when it influenced other themes, such as function; many still felt the need to legitimize their foot pain in order for health professionals to take it seriously ("in the end I went to my GP because it had happened a few times and I went to an orthopaedic surgeon who was quite dismissive of it, it was like what are you complaining about”). Conclusions: Patients interpret the outcome of foot surgery using a multitude of interrelated factors, particularly functional ability, appearance and surgeons' appraisal of the procedure. While pain was often noted, this appeared less important than other factors in the overall outcome of the surgery. Future research into foot surgery should incorporate the complexity of how patients determine their outcome Disclosure statement: All authors have declared no conflicts of interes

The contribution of X-linked coding variation to severe developmental disorders

Abstract: Over 130 X-linked genes have been robustly associated with developmental disorders, and X-linked causes have been hypothesised to underlie the higher developmental disorder rates in males. Here, we evaluate the burden of X-linked coding variation in 11,044 developmental disorder patients, and find a similar rate of X-linked causes in males and females (6.0% and 6.9%, respectively), indicating that such variants do not account for the 1.4-fold male bias. We develop an improved strategy to detect X-linked developmental disorders and identify 23 significant genes, all of which were previously known, consistent with our inference that the vast majority of the X-linked burden is in known developmental disorder-associated genes. Importantly, we estimate that, in male probands, only 13% of inherited rare missense variants in known developmental disorder-associated genes are likely to be pathogenic. Our results demonstrate that statistical analysis of large datasets can refine our understanding of modes of inheritance for individual X-linked disorders

Interaction of antimicrobial peptides with bacterial membranes

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Fabrication and characterization of bioactive thiol-silicate nanoparticles

Here we describe a new method for the production of thiol-silicate particles and the entrapment of enzymes within the thiol particles as they are formed. When bio-inspired polymers (polyethyleneimine) are combined with a silicic acid source and phosphate buffer under pH neutral conditions, formation of silicate particles occurs. In the method presented here the silica source contains a thiol group and so therefore the silicate particles are pre-functionalized with thiol groups. We have termed the silicate particles produced “thiol particles” and the characterization of these thiol particles is also presented in this chapter. As enzymes can be entrapped during fabrication, it means that the thiol particles can not only attach to metal surfaces but also catalyse certain reactions depending on the enzyme used. This means that there are many future possibilities for the use of thiol particles containing enzymes, as they may be used in a wide range of processes and devices which require catalytic functionalized surfaces, such as biosensors and biocatalytic reactors

Influence of Shell Thickness on the Colloidal Stability of Magnetic Core-Shell Particle Suspensions

We present a Discrete Element study of the behavior of magnetic core-shell particles in which the properties of the core and the shell are explicitly defined. Particle cores were considered to be made of pure iron and thus possessed ferromagnetic properties, while particle shells were considered to be made of silica. Core sizes ranged between 0.5 and 4.0 μm with the actual particle size of the core-shell particles in the range between 0.6 and 21 μm. The magnetic cores were considered to have a magnetization of one tenth of the saturation magnetization of iron. This study aimed to understand how the thickness of the shell hinders the formation of particle chains. Chain formation was studied with different shell thicknesses and particle sizes in the presence and absence of an electrical double layer force in order to investigate the effect of surface charge density on the magnetic core-shell particle interactions. For core sizes of 0.5 and 4.0 μm the relative shell thicknesses needed to hinder the aggregation process were approximately 0.4 and 0.6 respectively, indicating that larger core sizes are detrimental to be used in applications in which no flocculation is needed. In addition, the presence of an electrical double layer, for values of surface charge density of less than 20 mC/m2, could stop the contact between particles without hindering their vertical alignment. Only when the shell thickness was considerably larger, was the electrical double layer able to contribute to the full disruption of the magnetic flocculation process

The formation of polyethyleneimine-trimethoxymethylsilane organic-inorganic hybrid particles

Polyethyleneimine–silica (PEI–silica) organic–inorganic hybrid particles were formed in the presence of multivalent anions, using trimethoxymethylsilane as the silica source. Here we present new understanding on the difference in particle formation when multi- and monovalent anions were used as well as providing clear evidence that anions other than phosphate may be used to produce PEI–silica particles, unlike the phosphorylated peptides involved in silication in nature. We also show that PEI–silica particle size increases with ionic strength when monovalent anions were used, but that the diameter is not ionic strength dependent with the use of multivalent anions. Furthermore, our results suggest that PEI–silica particle production involves the formation of polyethyleneimine aggregates with multivalent anions due to electrostatic interactions, producing sites from which silica particles can grow. In addition, for the first time zeta potential measurement data show the surface charge of the PEI–silica particles, giving evidence of the presence of the polyethyleneimine at the surface of the particles, without the need of an additional surface modification step. The superior understanding of silica particle growth in order to control the parameters needed to refine and improve the production of silica particles made using less toxic reagents is of great significance in silica particle fabrication and processing. In addition, the potential application of the polyethyleneimine on the silica particle surface is of great benefit since hybrid organic–inorganic silica particles have several applications from carbon dioxide capture to drug delivery in many fields of science, engineering and medicine

High-resolution analysis of the influence of reactant concentration on nucleation time and growth of polyethyleneimine-trimethoxymethylsilane particles

High-resolution dynamic light scattering (DLS), scanning electron microscopy (SEM), time-lapse photography, and attenuated total reflectance Fourier transform infrared spectroscopy were used to analyze the growth kinetics of polyethyleneimine (PEI)-silica particles fabricated from the condensation of hydrolyzed trimethoxymethylsilane (TMOMS) and PEI/phosphate buffer (PEI/PB). Depending on the concentration of hydrolyzed TMOMS and PEI/PB, three stages were identified. We observed the existence of a nucleation time that has never been reported in the literature when TMOMS has been used. During this nucleation time, particles of less than 25 nm were detected using in situ DLS measurements taken every 15 s (high resolution), a DLS time-scale resolution not previously reported. In addition, the length of the nucleation time depended mainly on the PEI/PB concentration, but also TMOMS concentration. The growth stage was evident from the rapid increase of particle size with time. Due to the high resolution of the DLS measurements, a peak could be observed in the particle diameter during particle growth, which corresponds to a secondary population of particles required for the larger particles to further increase in size. Finally, during the equilibrium region, particles reached their maximum diameter that was independent of the concentration of PEI/PB and only changed with concentration of hydrolyzed TMOMS