Cellular senescence is a state of permanent cell cycle arrest in which a cell is unable to further divide in response to normal growth stimuli. Telomere shortening, believed to be a mechanism of cellular senescence, is a result of numerous rounds of cell division and can be accelerated by heightened levels of oxidative stress. An accumulation of senescent T lymphocytes in blood and tissues has been suggested to contribute to the general immunosuppression seen in the elderly. Obese individuals and athletes taking part in regular high intensity exercise are subjected to heightened states of oxidative stress which appears to result in immunosuppression and increased susceptibility to infection. It was hypothesised that there would be an accumulation of senescent T lymphocytes with ageing, with obesity and during six months training for an Iron man competition. Senescent CD4+ and CD8+ T peripheral blood lymphocytes were identified by 4 colour flow cytometry, based on their cell surface expression of CD57, the killer cell lectin-like receptor G1 (KLRG1) and the lack of cell surface expression of CD28. Where telomere length measurements were performed, CD4+ and CD8+ T lymphocyte subsets were isolated and telomere lengths were compared to the proportions of KLRG1+, CD57+ and CD28+ cells in each subset. Older subjects and obese subjects had significantly larger proportions of senescent cells (KLRG1+/CD57+) in the CD8+ but not the CD4+ peripheral blood T lymphocyte subset. Furthermore, during six months training for an Iron Man competition, compared to the first month, club level athletes showed a 92% increase in the frequency of senescent cells (KLRG1+/CD57+) in the CD4+ but not the CD8+ T lymphocyte subset. Telomere length was negatively correlated with the proportion of KLRG1+ and CD57+ cells and positively correlated with the proportion of CD28+ cells in the CD4+ but not the CD8+ T lymphocyte subset. It is concluded from this work that KLRG1+/CD57+ senescent T lymphocytes accumulate with age, obesity and regular high intensity training, which may contribute to the increased immunosuppression associated with these states.

Background and aims: The experience of anger could affect cardiovascular (CV) and electro-encephalographic (EEG) parameters but such parameters could vary within the motivational context. Although models of motivational contexts were proposed by CV literature as challenge/threat (Blascovich & Tomaka, 1996) and by frontal EEG asymmetry literature as approach/avoidance (Harmon-Jones, 2004a) little is known whether a negative emotion such as anger could be indexed by CV and EEG responses within motivational contexts. Anger in a threat context may be particularly detrimental for health due to low control compared to anger in a challenge context, where control is high. Hence, the aim of the research was twofold: 1. to investigate how a motivational context (challenge vs. threat) influences the cardiovascular system and frontal EEG asymmetry during anger induction protocols and 2. to analyse the efficacy of ambient interventions (music, light) to reduce the impact of anger on cardiovascular responses. Affective computing through the use of ambient intelligence technology could be used to promote positive emotion or to ameliorate negative moods. Method: There were two anger induction protocols within the thesis. Firstly, anger was manipulated using an experimenter effect (i.e., rude vs. polite experimenter). Participants were exposed to a computer-based problem-solving task under conditions of control and no control which represented the motivational contexts of challenge/threat. Secondly, anger was induced by exposing participants to a time constrained driving schedule on a simulated route with financial penalties for any delays to arrive to the destination. Motivation was manipulated by exposing participants to traffic delays at an early (challenge) and later point (threat) on a simulated driving route. STAXI-2 (Spielberg, 1999) was used to measure anger states and motivation was measured by Confidence and Perceived Control Scale from Dundee Stress State Questionnaire (Matthews & Desmond, 1998). Psychophysiological variables included: blood pressure (BP), cardiovascular impedance (ICG), frontal EEG asymmetry, and facial electromyography (fEMG). Results: The cardiovascular and EEG results of the present thesis pointed to a circumplex model of anger with quadruplet facets along cardiovascular responses to challenge/threat contexts in conjunction with approach/avoidance tendencies where a threat motivation with avoidance was indexed by increased blood pressure and cardiac output and by greater right frontal activation. The difference in the approach-threat responses was the activation of the left hemisphere. The challenge-avoidance state was defined by increased total peripheral resistance (TPR), systolic blood pressure (SBP), heart rate (HR), mean arterial pressure (MAP) and greater right frontal hemisphere activation. No frontal asymmetric activity was identified in the challenge-approach, but increased TPR, SBP, HR and MAP were observed. The ambient intervention results suggested that cardiovascular responses (e.g., SBP) could be reduced by low activation music or blue ambient light. Discussion and conclusions: Anger in the context of challenge can be distinguished from anger in the context of threat via a specific pattern of CV (systolic BP) and EEG measures (frontal peripheral brain site). Ambient interventions (low activation music or blue light) could be factors in modulating physiological reactions while driving; discrepancies between self-report measures and physiological responses, low sensitivity of impendence data to manipulations and low impact of various colour ambient lights on cardiovascular responses were addressed within a theoretical and methodological.

A novel screening method for detecting lignin-degradation activity on agar plates was developed using nitrated lignin. Using this method, ten lignindegrading bacteria have been isolated from environmental sources, including seven mesophilic soil bacteria and three thermotolerant strains from composted wheat straw. All of the isolates have demonstrated activity towards lignin degradation in the assays, the most active strain being a thermotolerant Sphingobacterium strain from the Bacteroidetes family. The ability of each strain to degrade a variety of aromatic carbon sources and size-fractionated Kraft lignin has been examined by laboratory-scale growth experiments and gel filtration chromatography respectively, and the bioconversion of different lignin-containing feedstocks by three of the most active strains has been examined in a series of laboratory-scale fermentation experiments. Purification of extracellular lignin-degrading enzymes from the culture supernatant of Sphingobacterium sp. has highlighted several different enzyme activities and possible lignin-degrading enzymes.

Touch is a sense with which humans are able to actively explore the world around them. Primary somatosensory cortex (S1) processing has been studied to differing degrees at both the macroscopic and microscopic levels in both humans and animals. Both levels of enquiry have their advantages, but attempts to combine the two approaches are still in their infancy. One mechanism that is possibly involved in determining the reponse properties of neurons that are involved in sensory discrimination is inhibition by γ-aminobutyric acid (GABA). Several studies have shown that inhibition is an important mechanism to “tune” the response of neurons. Recently it has become possible to measure the concentration of GABA in vivo using edited Magnetic Resonance Spectroscopy (MRS), whereas magnetoencephalography (MEG) offers the possibility to look at changes in neuromagnetic activation with millisecond accuracy. With these methods we aimed to establish whether in vivo non-invasive neuroimaging can elucidate the underlying neuronal mechanisms of human tactile behaviour and to determine how such findings can be integrated with what is currently known from invasive methods. Edited GABA-MRS has shown that individual GABA concentration in S1 correlates strongly with tactile frequency discrimination. MEG was used to investigate the neuromagnetic correlates of a frequency discrimination paradigm in which we induced adaptation to a 25 Hz frequency. We showed that S1 is driven by the adapting stimulus and shows that neural rhythms are modulated as a result of adaptation. This is the first time that behavioural psychophysics of tactile adaptation has been investigated using complimentary neuroimaging methods. We combined different methods to complement both physiological and behavioural studies of tactile processing in S1 to investigate the factors involved in the neural dynamics of tactile processing and we show that non-invasive studies on humans can be used to understand physiological underpinnings of somatosensory processing.

This Thesis presents an analysis of the role of interleukin (IL)-1α (IL-1α) as a potential future surrogate biomarker for AAA. It is the only research work to date to have looked into the role of IL-1α as a biomarker in AAA disease, correlating titres with different anatomical, morphological and patient-related factors. It is the first piece, in over 20 years of published literature, to have performed a robust methodology study on the measurement of IL-1a in serum samples using different techniques. A comparison study of commercially available immunoassays in the context of IL-1α has never been undertaken before, and we are the first to undertake one. Additionally the work on the natural history of AAA is one of the largest single-centre cohort studies to analyse AAA growth in surveillance. The work covers three main areas: identifying why current strategies for monitoring AAA are ineffective, analysis of different serum processing methodologies and commercially available immunoassays used to measure IL-1α, and linking IL-1α to different anatomical, morphological and patient-related AAA factors.

Hypertensive disorders of pregnancy are an increasingly common disorder in modern society. The increasing prevalence of women with pre-eclampsia superimposed on a background of chronic hypertension is a significant burden in modern society and is profoundly detrimental to both mother and child; during pregnancy and beyond. Little is understood about the development of these multifactorial hypertensive disorders, however there is increasing evidence that the manifestation of hypertensive disorders during pregnancy is not solely due to placental-derived dysfunctions and has important maternally-driven components. The stroke-prone spontaneously hypertensive (SHRSP) rat is a well-established model of human essential hypertension. SHRSP dams remain hypertensive throughout pregnancy and demonstrate an abnormal uterine artery structure and function at term. This project aimed to more fully characterise pregnancy in the SHRSP rat. The objectives were to assess maternal responses and determine how maternal hypertension impacts maternal and fetal well-being as well as placental development; to investigate the underlying genetic mechanisms behind the eventual abnormal pregnancy-dependent uterine artery remodelling; and, finally, to increase the maternal cardiovascular load in SHRSP pregnancy to establish a model of superimposed pre-eclampsia. In vivo and ex vivo techniques were used to characterise cardiovascular function in the hypertensive SHRSP and normotensive WKY rats during gestation, as well as assess pregnancy outcomes. The SHRSP dams were found to have similar cardiac function compared to WKY, yet there was evidence of impaired systemic vascular structure and function in late gestation and placental abnormalities. Nevertheless, the SHRSP maintained similar litter sizes to WKY and did not demonstrate any major impact on fetal growth. Further similarities between SHRSP and WKY pregnancy were revealed with the assessment of uterine artery function in early gestation. However, using RNA sequencing to elucidate the transcriptomic profiles of the uterine arteries, SHRSP were found to have strikingly different responses to pregnancy at the transcript expression level, compared to WKY. Finally, a model of superimposed pre-eclampsia was established by increasing the cardiovascular stress in the dam using angiotensin II infusion during pregnancy in SHRSP. This model had a significantly higher systolic and diastolic blood pressure than the already hypertensive SHRSP. The pregnancy-dependent increase in cardiac output, observed in SHRSP, was negated by AngII infusion and was reduced in the highest treatment group. These major cardiovascular impairments were observed alongside increased proteinuria and reduced fetal growth; all phenotypes found in severely pre-eclamptic women. This work has provided information on systemic and uterine specific vascular responses to pregnancy in SHRSP and WKY rats alongside detail of underlying transcriptional differences. This study was the first to examine uterine artery gene expression changes during pregnancy. The different transcriptomic profiles of early pregnancy changes in the two strains make this an intriguing model to study maternal-driven vascular remodelling in hypertensive pregnancy. Furthermore, this work demonstrated that increasing the cardiovascular load during pregnancy in SHRSP successfully mimics superimposed pre-eclamptic phenotypes and could be used in the assessment of novel therapeutic strategies. To conclude, the SHRSP has the potential to aid our understanding of human pre-eclamptic conditions, especially when endeavouring to determine the impact of maternally-driven components of hypertensive disorders of pregnancy.

Sub-critical water (SCW) hydrolysis has previously been used in the extraction of antioxidant compounds from a variety of food wastes, in-particular those which are rich in protein. The brewing industry generates high volumes of waste. The most abundant component, brewers' spent grain (BSG), is high in protein content. The work presented in this thesis aimed to investigate the SCW extraction of antioxidant compounds from BSG. Whilst SCW hydrolysis has proved effective in the extraction of antioxidants from a range of compounds its mechanism of action has not been thoroughly investigated. High performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (MS/MS) was used to analyse peptide production from the SCW hydrolysis of proteins. Sites of cleavage were identified and a mechanism of action of SCW on proteins was postulated. The results from this analysis raised the possibility of using SCW as a proteolytic reagent during proteomics experiments. Approaches for SCW-based proteomics were further explored by investigating SCW induced amino acid side chain modifications to aid peptide identification. To assess the antioxidant capacity of mixtures generated via SCW hydrolysis oxygen radical absorbance capacity, reducing power and comet assays were used. The decomposition products responsible for antioxidant capacity were characterised using MS/MS.

Nippostrongylus brasiliensis is a rodent intestinal nematode with an important pulmonary migrating stage. Previous studies have observed a lack of TNF-α production and minimal recruitment of neutrophils, which led us to the belief that anti-inflammatory mechanisms could be active in the lung stage. In this study, lipopolysaccharide (LPS) stimulated alveolar macrophages (NR8383) or rat lungs were used as in vitro or in vivo inflammation models respectively. Both live N.brasiliensis larvae and NES significantly reduced the production of LPS-induced pro-inflammatory mediators, TNF-α and NO, but not IL-1β, in NR8383 cells. The inhibition of TNF-α production was related to the heatlabile and trypsin-sensitive fraction of NES concentrate. 1-D protein gel of NES concentrate revealed that the molecular weights of proteins are between 6kDa and 100kDa. Glycoproteins were found abundant in NES concentrate. The inflammatory processes, including NF-κB translocation and TNF-α gene transcription were significantly inhibited by NES and/or NES concentrate. In vivo, we observed a significant reduction of neutrophil recruitment (≈ 40%) by NES on a background of LPS (100ng/ml) induced inflammation. This reduction was associated with the significant inhibition in gene transcriptions of proinflammatory mediators TNF-α, IL-1β, iNOS, ICAM-1 and MIP-2 in bronchoalveolar lavage (BAL) cells. The down-regulation of pro-inflammatory mediators and inflammatory processes observed in this study suggests that N.brasiliensis larvae and/or NES are capable of modifying the normally potent LPS inflammatory response, both in vitro and in vivo. This study and planned future studies could be fundamental in developing anti-inflammatory agents with immune-active molecules in N.brasiliensis-derived products.

The work presented in this thesis is concerned with modelling the growth of tissue constructs, with particular focus on the effects the local micro environment has on the cell cycle and metabolism. We consider two cases; multicellular tumour spheroids and orthopaedic tissue constructs. This thesis is divided into two parts. In the first part we will present a multispecies model of an avascular tumour that studies how a cell’s metabolism affects the cell cycle, spheroid growth and the mechanical forces that arise during growth. The second part consists of a study of the growth of an engineered cartilaginous tissue layer. Experimental observations will be compared to a model of the distribution of cells and extracellular matrix. The efficiency of cancer treatments such as radiotherapy and chemotherapy are sensitive to the local environment of a cell. Therefore an essential task in tumour biology is to understand the microenvironment within a tumour. Many mathematical models study the effects of nutrients and waste products, usually assuming growth is limited by the diffusion of a single nutrient. We will look in detail at the metabolic pathways from which cells obtain energy (ATP). A multispecies model is presented that considers the transition from aerobic to anaerobic respi- ration and includes relevant chemical and ionic buffering reactions and transport mechanisms. Results show that potential ATP production affects the cell cycle and consequently the rate of growth. This model is simplified using mathematical analysis and is integrated with a morphoelastic model to study the development of mechanical forces. The model shows that mechanical effects are particularly important during necrosis, where large tensile forces are shown to develop. A review of the equations governing nutrient conservation is given, by developing alternative macroscopic equations based on the microscopic features of a tumour using homogenization techniques. The second part of this thesis studies the growth of cartilaginous tissue. Bio-materials are being engineered in an attempt to replace dysfunctional tissue in the human body using cells extracted from living organisms. We model the growth of a cartilaginous tissue construct that has been grown from expanded chondrocytes seeded onto collagen coated filters. A model is developed to explain the distribution of cells and the concentration and distribution of collagen and GAGs. This is achieved by studying the local environment of the cells. Model predictions are compared to a range of experimental data and show most of the growth takes place in the upper region of the construct.

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