No description available.

The epidemiology of foot complications in patients with rheumatoid arthritis (RA) is poorly understood. A number of patients report ongoing foot-related pain, impairment, footwear restriction and activity limitation, despite developments in pharmacological disease management. Forefoot bursae (fluid filled sacks, FFB) have been previously shown to be highly prevalent and related to foot complications in patients with RA. However, the longitudinal epidemiology and clinical importance of FFB in this patient population remains unclear. It is anticipated that an improved understanding of the mechanisms by which FFB are responsive to, or contribute to, fluctuations in RA disease activity will inform future evaluation of foot health and novel therapeutic targets. Through a series of four experimental studies this work has shown that ultrasound (US) detectable FFB are highly prevalent in patients with RA compared to healthy volunteers (HV) and are clinically relevant. The natural history of FFB remains consistent longitudinally in a cohort of patients with established RA disease at baseline. US-detectable FFB were determined to be significant prognostic indicators of foot-related disability after three years. Furthermore, the distribution of US-detected FFB across forefoot sites was identified as significantly different between HV and patients with predominantly inflammatory or degenerative arthritis; uniquely patients with RA have a number of FFB within the central forefoot region, in addition to those located laterally, which were frequently present in all comparative groups. Thus, in patients with RA ~50% of US-detected FFB may be of greatest clinical relevance, due to their positioning within the central forefoot region. Detection of FFB using MRI defined a series of FFB characteristics of clinical relevance in patients with RA. The presence of plantar forefoot fluid lesions or intermetatarsal soft tissue lesions was significantly related to RA disease activity. The presence of plantar soft tissue lesions was significantly related to increased biomechanical impairment. However, a high proportion of plantar predominantly soft tissue FFB was also noted to be actively inflamed whilst other MRI-based markers of disease activity within the forefoot were minimal.

Microfluidic impedance cytometry is the dielectric characterisation of single particles flowing through a microfluidic channel. Microfluidic impedance cytometry offers a novel solution to counting and discrimination of dfferent particles and cells. One application is discrimination of different blood cell types in a low cost Point of Care device. However,the accuracy of currently available systems is poor and inadequate for clinical use. A full numerical model, developed in this research, demonstrated that the main source of measurement inaccuracy relates to the position of the particle in the micro-channel. Particles travelling at the top or bottom of the channel close to the electrodes were found to have a higher impedance signal compared with particles travelling through the centre of the channel. Counter-intuitively, the model also showed that although the electrode geometry is symmetrical, the variation in signal is asymmetric about the vertical position of the particle within the channel. A new electrode geometry was developed to minimise particle positional dependence. When combined with new signal processing techniques which were also developed, this led to marked improvements in measurement accuracy. For example, the coefficient of variation of monodisperse beads were half the manufacturer's data. Applications of the improved device were investigated by analysing a range of different cell types in blood. Measurements of the distribution width of red blood cells were successful and found to be within the known clinical range. It was also shown that combined with pre-enrichment techniques, the device successfully detected clinically relevant concentrations of individual tumour cells in a background of 106 times more white blood cells. In order to use microfluidic impedance cytometry for diagnostic blood counting applications, lysing of the more numerous red blood cells is required. Lysing methods suitable for implementing in a Point of Care device were evaluated and a stirred mixing system was developed. In summary, this thesis describes a new, high accuracy microfluidic impedance cytometer which has the potential to be integrated into a miniature blood counting device for Point of Care analysis.

No description available.

Epidemiological evidence suggests poor fetal growth is associated with poor later respiratory health, including the important childhood disorders asthma and wheeze. Factors creating a suboptimal early environment may persistently alter the structure and function of the immune and respiratory systems. This thesis explored the early life origins of paediatric asthma and wheeze in a large, prospective mother-child cohort. In particular, the contributions of maternal nutrition, and fetal and postnatal growth were assessed. The mothers of healthy, term infants had their body composition, lifestyle and diet characterised before and during pregnancy. Serum anti-oxidants, vitamin D and polyunsaturated fatty acids were measured in late pregnancy. Fetal growth was recorded by longitudinal ultrasound scans. 1548 children were followed to age 3 years and 469 were seen at 6 years. Wheeze was assessed by questionnaire and skin prick testing and detailed lung function measures were performed. Late pregnancy fetal growth faltering was associated with an increased risk of atopy and atopic wheeze at age 3 years, and greater weight and adiposity gain in the first year of life were associated with increased risk of wheeze. In those children seen at 6 years, greater maternal adiposity, before and during pregnancy, was associated with increased risk of non-atopic wheeze. Lower maternal pre-pregnancy vitamin D intake was associated with increased risk of childhood asthma, recent wheeze, and non-atopic wheeze. Lower maternal serum 25(OH) vitamin D in late pregnancy was also associated with childhood asthma and wheeze. Higher late pregnancy energy-adjusted vitamin A intake was associated with higher forced expiratory volumes but also greater bronchial hyperresponsiveness. Higher arachidonic acid status during pregnancy was associated with markers of atopy and greater risk of atopic wheeze. These results suggest early life factors contribute to paediatric asthma and wheeze. Optimising the early environment may reduce the burden of childhood wheeze

No description available.

Anaemia is common and frequent in HIV infection and Acquired Immune Deficiency Syndrome (AIDS). This study was aimed at exploring the interactions between the effects of HIV infection and other related anaemia-causing effects (reductive adaptation, reduced energy/nutrient intake and inflammatory and/or metabolic alterations), which may be responsible for most anaemia in this population. It is postulated that these interactions can heighten the risk levels for anaemia even in an asymptomatic HIV-infected population. The study is based on a secondary analysis of data from the Transition and Health during Urbanisation of South Africans (THUSA) survey, a population-based, cross-sectional study carried out in the North West Province of South Africa. Out of a sample population of 1854 ‘apparently healthy’ adults, aged ≥15 years, 216 (11.8%) were HIV sero-positive. A validated quantitative food frequency questionnaire was used to assess dietary intake and standard conditions and protocols used for anthropometric and biochemical measurements. Anaemia was defined using WHO haemoglobin (Hb) and haematocrit (Hct) definitions. Univariate ANOVA statistics showed that HIV-sero-positive subjects had lower Hb, Hct, serum iron, ferritin, total iron binding capacity (TIBC) but higher % saturation compared to their sero-negative peers. However, only the differences in Hct were significant (p<0.001). Anaemia prevalence was generally high but was higher though not statistically significant in sero-positives than sero-negatives (51.4% cf. 45.8%,p=0.123). Anaemia in the study population was mostly mild (about 65%), with a higher proportion of anaemia of chronic inflammation than iron deficiency anaemia. Vitamin a deficiency was significantly associated with anaemia (p=0.022). High serum total proteins, alanine transaminase (ALT), aspartate transaminase (AST) and low albumin were significantly associated with HIV sero-positivity. Predictors of anaemia in the study population by logistic regression modelling were settlement type (aOR,1.7;CI,1.2-2.5;p=0.004), serum albumin (0.6;0.4-0.9;p=0.016), TIBC (1.5;1.0-2.2;p=0.008), vitamin E (0.6;0.4-0.9;p=0.006), serum gamma-glutamyl transferase (0.6;0.4-0.9;p=0.007), Direct bilirubin (0.5;0.5-1.0;p=0.0446), and abdominal skinfold (1.8;1.2-2.5;p=0.004). HIV infection was not a significant predictor of anaemia in this asymptomatic population, but the virus and related inflammatory conditions may play a crucial role in the development of anaemia. Where HIV and other inflammatory stressors are prevalent, the overall burden of anaemia could also be increased

Hepatitis C virus (HCV) infection is a major global healthcare problem infecting 180 million people worldwide. Infection persists in 80% of patients and is thought to result from a failure to sustain an immune response to HCV. Current treatment with ribavirn and PEG-IFNα leads to a sustained viral clearance in 40-80% of patients. Despite its use for many years, the exact mechanisms of actions of ribavirin are poorly understood. These current treatments are poorly tolerated by many and therefore newer and more effective treatments are being investigated. This thesis investigated how current and novel treatments were able to modulate the immune response looking at effects on the innate immune response including dendritic cells and NK cells and their ability to stimulate T cells and the adaptive immune response. The aim of the work described in chapter 3 was to investigate the immunomodulatory effects of ribavirin on dendritic cell (DC) function. The results obtained suggest that ribavirin is able to modulate cytokine production from dendritic cells in response to maturation stimuli, in particular suppressing the production of IFNα from pDCS from both CHC and NHD patients but also TNFα, IL8 and IL10. In MoDCs from NHDs, ribavirin decreased CD40L-induced TNFα production but had no effect on other cytokines tested or on DC phenotype. These findings explain possible reasons behind the failure of monotherapy and dependence on co-administration of IFNα in treatment regimens. The aim of the work in chapters 4 and 5 was to investigate the immunomodulatory effects of two novel treatments, a novel helminth protein, rOv-ASP-1 and a TLR7 agonist, SM-360320. rOv-ASP-1 showed evidence of DC phenotypic maturation, based on up-regulation of phenotypic markers (CD40, HLA-DR, CD83 and CD86) and enhanced pro-inflammatory cytokine production (IL-6, IL-8 and TNFα). It was also shown to stimulate proliferation of allogeneic CD4+ T cells suggesting that the protein is able to enhance the accessory/antigen presentation by DCs. These findings suggest that this novel protein may be used as an effective immuno-stimulant to boost antigen specific responses or as a vaccine adjuvant. SM-360320 was shown to enhance viral clearance and immune modulation with induction of 2’5’OAS gene expression, inhibition of replication of HCV replicons in Huh 7 cells, enhanced secretion of anti-viral and pro-inflammatory cytokines, up-regulation of NK cell activation. These findings suggest that SM-360320 might provide complementary and additional mechanisms of action to current HCV therapies making it a promising novel treatment. Further investigation of these compounds is therefore warranted due to their potential widespread application in treating infectious diseases and immune mediated conditions

No description available.

Cystic Fibrosis (CF) causes chronic lower respiratory tract infection leading to morbidity and mortality. CF Pulmonary Exacerbations (CFPEs) cause accentuated symptoms and increase mortality. The definition and aetiology of CFPEs has however proved elusive. Recently, culture independent techniques have shown that there is much greater diversity of bacteria than previously detected by culture dependent methods. Building on this, in the work presented here, the bacteria in respiratory samples from adults with CF were studied over a 12 month period. Each subject provided thrice weekly sputum samples for analysis by culture and culture independent microbiological methods. Concurrently an in-depth assessment of their subjective and objective health using Visual Analogue Scales (VAS) and spirometry (FEV1) was undertaken. Inflammation markers were also measured. A total of 2061 samples from fourteen adults (mean age 30.2; mean FEV1% predicted 53.3%; 6 females; 8 ?F508 homozygotes) were collected. Subjective VAS measures correlated with objective spirometric measures. However, previously unsuspected complexity of subjective symptomatology was found. Ribosomal clone sequence analysis identified 90 different species, including 15 not previously reported in CF lung disease. Notably 44% of species detected were obligate anaerobes, and 72% were species previously associated with the human oro-pharynx. During the study period, subjects experienced 42 CFPEs requiring treatment. New species were not seen to enter the bacterial community as aetiological agents for CFPEs. However, whilst treatment for CFPEs caused a large fall in the proportion of anaerobic species, no significant change in the proportion of Pseudomonas aeruginosa was detected. Significant and potentially important differences in bacterial community composition, structure and stability between subjects separated by gender, genotype and lung function were observed. Moreover, the presence of certain species correlated with subjects suffering frequent CFPEs. The results presented here give new insights in to the complexity of symptoms and bacterial diversity in CF pulmonary disease