Monocytes are haematopoietic stem cell-derived, immune effector cells. In mice, monocytes consist of two principal subsets: the classical Ly6C-expressing subset and the patrolling Ly6Clow subset. The origin and fate of Ly6Clow monocytes remains a topic of debate, as does their interrelationship with Ly6C+ monocytes. The current model of Ly6Clow monocyte development suggests that Ly6C+ monocytes are the obligate, steady state precursors of the Ly6Clow subset, undergoing conversion or maturation within the blood. However, several studies have reported differing genetic dependencies of monocyte subsets that are in conflict with this model of Ly6Clow monocyte development. To re-investigate monocyte precursor-product relationships, this project combined genetic, kinetic and adoptive transfer studies to probe the interrelationships between bone marrow precursors, blood monocytes and tissue macrophages. This study firstly confirms the existence of a third, minor monocyte subset that expresses MHC II and varying levels of Ly6C and is found in the blood, spleen and bone marrow monocyte compartments. Secondly, this study establishes that all three monocyte subsets arise in the bone marrow from a proliferating common pro-monocyte via two genetically distinct lineages. This study demonstrates that Ly6Clow MHC II- monocytes arise from a novel Nr4a1-dependent, Irf8-independent intermediate population in the bone marrow compartment under steady state conditions, whereas. Thirdly, Nr4a1-dependent monocytes have a long half-life and circulate within the systemic and splenic vasculature, contributing minimally to tissue macrophage populations under steady state conditions. The findings in this thesis clarify and extend our understanding of monocyte genetic and functional heterogeneity.

Introduction: Point-of-Care Testing (POCT) also widely known as Near Patient Testing (NPT), is pathology testing performed at or near the site of patient care, offering several advantages over traditional pathology testing: it is portable, provides rapid results, uses smaller sample sizes and can be used for patient self-testing (PST). Due to these differences, it is conceivable that the implementation of POCT in place of laboratory testing could have an impact on patient experience; therefore, the aim of this research was to investigate this impact. The specific objectives of the study are to identify where and how POCT is currently used, to assess its impact on patient outcome and experience within a community setting and to evaluate its performance in the community setting. Methods: A survey was performed to gain insight on the extent to which POCT is used within UK primary care, how well established it is and general attitudes toward its use. A cross-sectional study, employing both quantitative and qualitative methods was conducted with patients receiving local authority provided NHS Health Checks in the community, where POCT is used to measure cholesterol and glucose. The analytical and operator performance of the POCT used was also assessed. Results: UK primary care staff were aware of POCT; 86% of respondents reporting that their surgery used some form of POCT on a regular basis. It appeared, however, that POCT operators were not always trained and that the quality of results obtained was not always considered. The use of POCT in community-based NHS Health Checks was well received and enabled the screening of individuals who would not normally access healthcare. However, the programme as a whole did not instigate significant improvements in the cardiovascular health of the participants, unless the participant was referred for further testing. The POCT used produced results that were significantly different from the reference value, producing clinically significant changes in outcome. Conclusion: The use of POCT should be tightly managed in every setting, including the community. This management should include regular quality checks to ensure patient results are accurate and that clinical management decisions are appropriate.

In magnetic resonance (MR) imaging it is usually assumed that the acquired data represent samples of the Fourier transform of the object. However, there are many cases where this assumption is violated due to system imperfections, subject motion and deliberate undersampling in an effort to reduce scan times. This can lead to artefacts in the reconstructed images. In this thesis two emerging clinical applications of MRI are considered: hybrid PET-MR imaging and coronary MR angiography (CMRA). Factors giving rise to substantial deviations from the basic Fourier model in these cases are described and methods to reduce artefacts by incorporating additional information into the reconstruction are presented. This information is either in the form of additional measurements, or as sparsity priors. Two major limitations of current techniques for PET attenuation correction using ultrashort echo-time MRI are addressed: Artefacts due to eddy currents and prohibitively long scan times. To account for eddy currents the use of a magnetic field camera to measure the true k-space trajectories is proposed. The method is demonstrated in numerical and tissue phantoms and in vivo cranial imaging of healthy volunteers. Parallel imaging and compressed sensing are then explored to accelerate the acquisition. A method to improve motion correction for CMRA is also proposed based on a novel image navigation scheme. This method uses a golden radial trajectory, which provides both high-temporal-resolution translational and low-temporalresolution affine motion estimates from the same navigator data. The approach is demonstrated in healthy volunteers, leading to improved depiction of the coronary arteries compared to when correcting only for translational motion. Furthermore, the proposed method gives rise to a predictable and reduced scan time compared to a gated diaphragmatic navigator scan, while maintaining a high image quality. The advances in the reconstruction that are proposed in this thesis help to tackle some of the major problems with UTE-based attenuation correction for PET and with CMRA. The proposed methods help to bring these emerging applications of MRI towards routine clinical practice.

<i>Hypotheses. </i>The severity and specific anatomical location of an initial traumatic injury are important in determining the level of risk of subsequent post traumatic respiratory compromise. An immediate post-traumatic stress response can be identified, and the subsequent activation of the inflammatory and coagulation cascades can be related to the degree of injury sustained and the subsequent development of complications. <i>Results. </i>Regression analysis of possible epidemiological factors determining the risk of ARDS demonstrated that the Injury Severity Score (ISS), the presence of a femoral fracture, the combination of long bone and abdominal injuries and unstable physiological observations on admission were each independently associated with ARDS. In the prospective clinical cohort study, the serum concentrations of a number of mediators, particularly interleukin-6, was shown to correlate with the severity of injury. However, no marker was found to be a useful indicator of the later development of respiratory insufficiency. In the laboratory study, an immediate depressant response of the cardiovascular system to injury was identified, the components of the stress response were observed to evolve in a reproducible manner, and the additional surgical treatment of the injury was not found to make a significant difference to this response. <i>Conclusion. </i>Several epidemiological, clinical and laboratory factors contributing to the development of the post-traumatic stress response are measurable. A group of patients at increased risk of respiratory insufficiency can be identified by their epidemiological features, but the role of measurements of inflammatory and coagulation activation remains to be defined.

No description available.

No description available.

The assessment of serum proteins has become of great importance in the diagnosis and management of many human diseases. Two methods currently used for this purpose are electrophoresis and immunoelectrophoresis both of which separate serum proteins according to their charge. However, in recent years two simple techniques have become available which separate proteins principally according to their molecular size. These methods are sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE) and gel filtration chromatography. The aim of this thesis was to examine these methods and to see if they could be profitably applied to the analysis of serum proteins. In particular, emphasis was placed on the assessment of the molecular size of the serum immunoglobulins in certain diseases. In Chapter one a general introduction was given about the serum proteins and several specific protein disorders were considered. In Chapter two the methods of SDSPAGE and gel filtration were described. In addition, these methods were used in an analysis of various pathological sera. The sera of eight patients with multiple myeloma were found to contain paraproteins of atypical molecular size. These were considered to be paraproteins with heavy chain deletions or light chain dimers. In Chapter three a study was undertaken of the clinical and immunological features of 25 patients with IgA myeloma. These patients were divided into two groups on the basis of the degree of paraprotein polymerization. The first group comprised those patients in whom the IgA paraprotein was greater than 50% polymerized, whilst in the second group the paraprotein was predominantly monomeric. No clinical or pathological differences were seen between the 'polymeric' and 'monomeric' groups of myeloma apart from that directly attributable to the physicochemical effect of the paraprotein polymerization. Thus, five patients out of 11 of the 'polymeric' group developed the hyperviscosity syndrome, whilst no patients in the 'monomeric' group developed this complication. The concentration of the paraprotein during the course of the disease was comparable in both groups. Chapters four, five and six were concerned with the detection, biological properties and clinical significance of circulating immune complexes containing IgG. To detect these complexes the method of gel filtration was used. The rationale for using this method was based upon the fact that complexed IgG has a larger molecular size than non complexed or monomeric IgG and thus elutes in earlier fractions of the chromatogram. However, SDSPAGE is of no use in detecting complexed IgG as SDS (an anionic detergent) dissociates immune complexes. In Chapter four a general review was undertaken of the implications of circulating immune complexes and the methods used for their detection. It was concluded that while immune complexes have been implicated in the pathogenesis of a large number of human diseases, there is no simple and sensitive method currently available to detect all forms of complexes. In Chapter five IgG containing complexes were detected in the majority of the sera of 35 patients with rheumatoid arthritis. These complexes v/ere small, eluting between IgG and IgM, and were not seen in the sera of healthy subjects. A monomer to complexed IgG ratio was used for quantitation of the complexes. This ratio was derived from the IgG profile obtained by gel filtration of the serum. The quantity of complexes correlated significantly with inhibition obtained by the rheumatoid sera of cytolysis in vitro of IgG sensitised target cells by K cells from human peripheral blood. A significant inverse correlation was observed between the quantity of serurn complexes and the chemotactic index of the circulating polymorphonuclear leucocytes obtained from the same rheumatoid patient. This suggests that these complexes may be implicated in the suppression of polymorphonuclear leucocyte chemotaxis observed in patients with rheumatoid arthritis. There was no correlation between the quantity of the complexes in the sera and other clinical, haematological and biochemical measurements. In addition to these rheumatoid patients the presence of complexes in the sera of patients with other joint diseases was also assessed. In some of these latter patients complexed IgG was found. In Chapter six four groups of patients were studied for the presence of circulating immune complexes. The first group comprised 19 patients having newly diagnosed acute myeloid leukaemia. The IgG in the majority of these patients' sera eluted in a normal position and complexed IgG was not detected. The second group was comprised of 11 patients with cutaneous vasculitis. Serum from these patients was examined for cryoglobulin and for complexed IgG. It was observed that complexed IgG was present in six of these sera and was generally associated with the presence of cryoglobulin and with a significant inhibition of K cell mediated cytotoxicity but not always so. In addition, in two patients active vasculitis was seen without the presence of either a cryoglobulin or complexed IgG. In the analysis of the cryoglobulins it was concluded that SDSPAGE might be a rewarding method. The third group consisted of 26 patients with multiple sclerosis. The percentage inhibition of K cell mediated cytotoxicity by the serum of these patients was similar to that obtained by serum from patients with other neurological disorders. In addition no significant inhibition of cytotoxicity was obtained with any of the cerebrospinal fluid of these patients. Immune complexes are unlikely to be present in the serum or cerebrospinal fluid of these patients. The fourth group consisted of 7 patients with a variety of diseases. One serum from a woman suffering from severe pre eclampsia was found to have complexed IgG. In Chapter seven SDSPAGE was used to analyse the blood/CSF barrier in 27 patients with non demyelinating or non infectious neurological diseases. It was concluded that this barrier acts as an efficient molecular sieve to plasma proteins and that SDSPAGE of CSF was a simple means of assessing this barrier. From the examples given above it was generally concluded that the assessment of the molecular size of serum proteins can provide information supplementary to that obtained using the current electrophoretic methods. It is hoped that now simple techniques are available, the assessment of protein molecular size will be more frequently performed in routine clinical practice. The topic of Chapter eight deviated from the central theme. In this chapter an examination was undertaken of the cerebrospinal fluid immunoglobulins in various neurological diseases. An increase in the CSF IgG/albumin quotient was observed in 19/36 (53%) cases of definite multiple sclerosis, in 13/47 (28%) cases of probable or possible multiple sclerosis, in 6/9 cases of proven herpes simplex encephalitis, in 3/4 cases of neurosyphylis, in 1/1 case of subacute sclerosing panencephalitis, in 2/9 cases of other neurological infections and in 2/12 cases of polyneuritis when compared with a group of 236 patients having other neurological diseases. In many of these patients a comparison was also made between the IgG/albumin quotient and the CSF kappa/lambda ratio and the CSF and serum viral antibody titre. It was concluded that the measurement of CSF IgG/albumin quotient is a valuable adjunct in neurological diagnosis and can be supplemented by the measurement of the CSF kappa/lambda ratio or antibody titres to certain viruses.

Sleep fragmentation is the term used to describe brief awakenings or microarousals from sleep which are less than 15 seconds long and often occur without the awareness of the sleeping subject. Arousals is the collective term for awakenings >15 seconds and microarousals < 15 seconds. Patients with sleep apnoea/ hypopnoea syndrome (SAHS) have recurrent upper airway obstructions during sleep usually terminated by arousals and decreases in oxygen saturation. They suffer from impaired daytime function which correlates weakly with their nocturnal hypoxemia and sleep fragmentation. These are interrelated making it difficult to distinguish which is the cause of daytime dysfunction in SAHS patients. This thesis examines the impact of sleep fragmentation alone on daytime function by inducing sleep fragmentation in normal subjects and studying their subsequent daytime function. A problem associated with studying sleep fragmentation is its poor definition. Current arousal definitions use a combination of a greater than 1 second increase in EEG frequency with or without increased EMG activity depending on sleep stage. This can lead to difficulties in comparing results between studies. Although the American Sleep Disorders Association (ASDA) has published guidelines on visual scoring of arousals they have not been validated or compared with other arousal definitions currently in use. Therefore 3 different arousal definitions and 1 definition of awakening were compared in SAHS patients. The definitions were (1) ASDA (3 seconds), (2) ASDA modified to 1.5 seconds, (3) Cheshire 1.5 second. The awakening was defined as a Rechtschaffen and Kales' stage shift to wakefulness. There were significantly more arousals of any kind than awakenings, and significantly more 1.5 second arousals by either definition than ASDA arousals. However not all apnoeas and hypopnoeas were terminated by visible EEG arousals with at best, 83% of respiratory events being terminated by 1.5 second ASDA arousals. There were weak but significantrelationships between microarousals scored by any definition and daytime sleepiness on the multiple sleep latency test (MSLT). The first sleep fragmentation protocol examined the effects of one night of induced visible EEG arousals on the daytime function of normal subjects. The subjects were objectively sleepier during the day after fragmentation as measured by both the MSLT and the maintenance of wakefulness test (MWT). Subjects had altered mood on the UWIST mood adjective checklist following sleep fragmentation; energetic arousal was diminished all day except at 12.00, hedonic tone was decreased at 10.00, and tense arousal was increased at 08.00 and 10.00. Subjects had impaired performance on 2 tests of cognitive function; Trailmaking B, a test of mental flexibility, and on PASAT 4 seconds, a test of sustained attention. These deficits were similar to those seen in SAHS patients prior to CPAP therapy. There are subgroups of patients with sleep apnoea whose apnoeas and hypopnoeas occur when they are lying supine or when they are in REM sleep. This allows them to obtain periods of uninterrupted sleep which may be sufficient to overcome any daytime dysfunction that may have occurred due to their REM or posture related sleep apnoea. Therefore 2 fragmentation paradigms were compared; regular fragmentation every 90 seconds of sleep, and clustered fragmentation every 30 seconds for 30 minutes every 90 minutes. There was no difference in arousal frequencies between study nights. There were no differences in daytime function despite significantly less stage 2 and more slow wave sleep on the clustered fragmentation night. This suggests that deficits in daytime function are dependent on sleep fragmentation and not stage 2 or slow wave sleep. Not all apnoeas and hypopnoeas are terminated by visible EEG arousals but are terminated by transient increases in blood pressure. The impact of these transient increases in blood pressure on daytime function are unknown. Therefore daytime function was compared after an undisturbed night's sleep and one night of sleep fragmentation to cause blood pressure elevations alone without coincident visible EEG arousals. There wassignificantly less slow wave sleep on the fragmented study night but there was no difference in visible EEG arousals between study nights. Non-visible sleep fragmentation made subjects sleepier during the day on the MSLT and MWT, and decreased hedonic tone upon awakening. There was no effect on cognitive function. Finally changes in EEG frequencies during visible EEG arousals were examined using Fast Fourier Transformation (FFT). There were significant increases in all physiological frequencies of human sleep within 5 seconds of the start of an arousal. During the non-visible fragmentation night alpha EEG power was determined with FFT. There was a significant increase in peak alpha power within 5 seconds of a tone whether that tone produced a visible EEG arousal or not. This suggests that computerised analysis of the EEG may be useful in measuring sleep fragmentation

Wegener's Granulomatosis, classically, comprises a triad of granulomatous vasculitis in the upper and lower respiratory tracts, and a focal and segmental, necrotising glomerulonephritis in the kidney. In practice disease presentation and organ involvement is widespread and variable. The aetiology is unknown but an infectious aetiology has been proposed, based on the especial involvement of the respiratory tract in the disease process. The pathogenesis is also unclear but immune complex deposition leading to neutrophil chemotaxis and activation causing endothelial injury has been suggested. Recently antibodies against a component of neutrophil cytoplasm have been described in Wegener's Granulomatosis. This thesis records studies of the diagnosis and pathogenesis of Wegener's Granulomatosis. The first part of the study examined the problem of diagnosis using renal biopsy material. Renal biopsy is important because renal functional status is the major factor determining outcome, yet renal biopsy appearances are not specific for the condition and may be found in other vasculitides such as microscopic polyarteritis. Review of the histology, immunofluorescence studies and ultrastructure of renal biopsies from patients with Wegener's granulomatosis and microscopic polyarteritis revealed no diagnostically useful differences. In Wegener's Granulomatosis renal mast cells were frequently present unassociated with areas of active inflammation, whereas in microscopic polyarteritis they were predominantly present as part of an inflammatory infiltrate. In both conditions the number of mast cells was increased. The functional significance of this difference is unclear. The second part of the study examined the presence of autoantibodies against neutrophils. IgG antibodies giving coarse, granular, cytoplasmic fluorescence when incubated with cytospin preparations of normal neutrophils were found to be highly specific for Wegener's Granulomatosis. Diffuse cytoplasmic fluorescence was present in a wide variety of other diseases including some other forms of systemic vaculitis. By differential protein extraction of neutrophils and Western Blot analysis IgG antibodies which gave coarse fluorescence were found to react with 45 kDa 27-31 kDa proteins in the membrane-bound protein extract. This is consistent with the autoantibodies being directed against a component of neutrophil granules. An hypothesis is proposed. Wegener's Granulomatosis is the product of an immunological response to an antigen, possibly to an inhaled, exogenous pathogen. A predominantly cell-mediated response results in the typical lesions identified pathologically within the respiratory tract including granulomata. A humoral response also may occur, reflected by the presence of specific autoantibodies and this can lead to systemic imjury primarily by the formation and deposition of immune complexes. In other systemic vasculitides, such as microscopic polyarteritis, a variety of exogenous antigens result in humoral responses and immune complex formation and deposition leading to the same pattern of renal injury.

Throughout the twentieth century clear professional demarcations have existed between the professions of radiography and radiology in respect of the nature of practitioners' work and responsibilities. Yet, in the last two decades, an extended scope of radiography practice has begun to blur traditional professional boundaries. In particular, the concept of advanced practice in radiography has the potential to improve the quality and quantity of services available for the benefit of patients. This thesis presents thirteen works published between 1998 and 2009, which collectively explore this changing professional landscape. Critical analysis of the contribution of the published works via extensive literature review, book reviews and citation / download analysis, demonstrated their utility and impact. The published works offer a distinctive and original contribution that supports the general development of radiography advanced practice, and in particular the emerging subspecialty of gastrointestinal imaging. Thematic analysis of the published works reveals their contribution to knowledge and understanding of radiography advanced practice in respect to the following themes: the drivers and barriers to implementation; the consequences of advanced practice; dissemination of advanced practice both within the United Kingdom and overseas; the influence of education; the required knowledge base, teaching, learning and assessment. The published works demonstrate that the concept of advanced practice has now been embraced within the UK radiography workforce, with increasing international interest in adopting practices pioneered by radiographers within the United Kingdom. The importance of reliable evidence for the success (or otherwise) of these emerging radiographer roles, coupled with the creation of relevant educational materials to support knowledge and skills development, is not to be underestimated if the contemporary professional landscape, to which this thesis contributes, is to significantly benefit patient care.