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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1251

Fcγ Receptors in the Immune Response

Díaz de Ståhl, Teresita January 2001 (has links)
<p>Circulating immune complexes play an important role in the modulation of antibody responses and in the pathogenesis of immune diseases. This thesis deals with the <i>in vivo </i>regulatory properties of antibodies and their specific Fc receptors.</p><p>The immunosuppressive function of IgG is used clinically, to prevent rhesus-negative women from becoming sensitized to rhesus-positive erythrocytes from the fetus. The mechanism behind this regulation is poorly understood but involvement of a receptor for IgG, FcγRII, has been suggested. It is shown in this thesis that IgG and also IgE induce immunosuppression against sheep erythrocytes to a similar extent both in mice lacking all the known Fc receptors as in wild-type animals. These findings imply that antibody-mediated suppression of humoral responses against particulate antigens is Fc-independent and that the major operating mechanism is masking of epitopes.</p><p>Immunization with soluble antigens in complex with specific IgG leads to an augmentation of antibody production. The cellular mechanism behind this control is examined here and it is found that the capture of IgG2a immune complexes by a bone marrow-derived cell expressing FcγRI (and FcγRIII) is essential. An analysis of the ability of IgG3 to mediate this regulation indicated that, in contrast, this subclass of IgG augments antibody responses independently of FcγRI (and FcγRIII). These findings suggest that distinct mechanisms mediate the enhancing effect of different subclasses of antibodies.</p><p>Finally, the contribution of FcγRIII was studied in the development of collagen-induced arthritis (CIA), an animal model for rheumatoid arthritis in humans. It was discovered that while DBA/1 wild-type control mice frequently developed severe CIA, with high incidence, FcγRIII-deficient mice were almost completely protected, indicating a crucial role for FcγRIII in CIA.</p><p>The results presented here help to understand how immune complexes regulate immune responses <i>in vivo</i> and show that Fc receptors for IgG, if involved, could be new targets for the treatment of immune complex-related disorders.</p>
1252

Meals and Food in Older Women : Health Perceptions, Eating Habits, and Food Management

Gustafsson, Kerstin January 2002 (has links)
<p>The aim was to describe and explore the food-related work and eating habits of older community-dwelling women, with Parkinson’s disease, rheumatoid arthritis or stroke or without these diseases. The major focus is on health perceptions, eating habits and meal support. A theoretical framework based on cultural and health theories was adopted. A total of 91 women between 64 and 88 years were visited in their homes, a food survey was performed consisting of a 24h recall and an estimated three-day food diary was introduced. Seventy-two of the women also took part in qualitative interviews with an ethnographic approach. Approximately one week later, another 24h recall was carried out at a second visit, or for the non-disabled women by telephone. The analyses revealed that many women were influenced by the prevailing health message and tried to eat a healthy diet. It was also important to them to enjoy their preferred foods, but this gave some women a bad conscience, while others perceived their usual foods as wholesome to eat. Health promotion for older women needs to incorporate the women’s own cultural context, their perceptions of food-related health, and their wish to adhere to their usual habits. Women with disease, frailty and who had become alone reported simplified food-related work and poor eating habits. However, management of these duties was highly valued, and women strove to cook by themselves as long as possible when disability became a threat. This resulted in a trend towards less nourishing cooked meals for women with disabilities. Thus, many women with these diseases living at home need support with their meals. This has to be planned in collaboration with the woman and build on her cultural values. The help must be performed with respect for the woman’s sense of order, be given sufficient time, and acknowledge her self-determination.</p>
1253

Intra-articular Glucocorticoid Treatment : Efficacy and Side Effects

Weitoft, Tomas January 2005 (has links)
<p>Intra-articular glucocorticoid injection therapy is frequently used to relieve symptoms of arthritis, but there is considerable variation in injection routines among physicians. One issue of debate concerns the importance of synovial fluid aspiration during the injection procedure. In the present randomised controlled study of patients with rheumatoid arthritis (RA), a significantly reduced risk for arthritis relapse was observed when arthrocentesis was included in the intra-articular injection procedure of the knee. </p><p>Furthermore, there is no consensus about the post-injection regimes. Previous studies have shown beneficial effects of post-injection rest of the knee, but also injection routines for other joints often include such recommendations. The present randomised controlled trial showed that 48-hour rest in elastic orthosis after intra-articular injection in the wrist did not improve the outcome. Thus, the effect of post-injection rest varies between different joints. </p><p>The improved treatment result of post-injection rest of the knee is supposed to be caused by retarded steroid resorption from the joint. In order examine the metabolic effects in cartilage, bone and the hypothalamic-piuitary-adrenal (HPA)-axis, resting and mobile RA patients were studied after intra-articular knee injections. Serum levels of the injected glucocorticoid, triamcinolone hexacetonide (THA), were analysed, as well as cartilage oligomeric matrix protein (COMP) as a marker of cartilage turnover, osteocalcin for bone formation and deoxypyridinoline for bone resorption. The HPA-axis was assessed using serum levels of cortisol and adrenocorticotropine hormone. The result showed a short term and reversible suppression of the HPA-axis and bone formation, whereas bone resorption was unaffected. No differences between mobile and resting patients were observed. In both groups reduction of COMP levels were seen, but these were significantly more pronounced in resting patients, suggesting a cartilage-protective effect. The THA levels increased similarly in both groups, indicating that rest did not affect glucocorticoid resorption. </p><p>Consequently, another explanation for the beneficial effects of postinjection rest of knee synovitis should be considered. In the present material the incidence of infectious complications of intra-articular treatment was less than 1/12,000 injections. </p><p>The findings in this thesis can be applied in the clinical practice and should be considered when new guidelines for intra-articular glucocorticoid therapy are created.</p>
1254

Asymmetric Synthesis of C-Glycosylated Amino Acids : Incorporation in Collagen Glycopeptides and Evaluation in a Model for Rheumatoid Arthritis

Gustafsson, Tomas January 2005 (has links)
This thesis describes stereoselective syntheses of four amino acids, three of which are C-glycosidic analogues of glycosylated amino acids. The overall goal of the project was to probe the interactions between MHC molecules, glycopeptide antigens and T cell receptors, that are essential for development of collagen induced arthritis. Collagen induced arthritis is a frequently used mouse model for rheumatoid arthritis, an autoimmune disease that attacks joint cartilage and leads to a painful and eventually crippling condition. The thesis is based on four studies. The first study describes the synthesis of hydroxylysine, an amino acid that is found in collagen and is an important constituent of the glycopeptide proposed as an antigen in collagen induced arthritis. During the synthesis of hydroxylysine some new insight into the mechanism of the reductive opening of p-methoxybenzylidene acetals was obtained. The remaining three studies deals with the synthesis of C-glycosidic analogues of glycosylated amino acids, hydroxy norvaline, threonine and hydroxylysine.The synthesis of each amino acid required control of several stereogenic centra and utilizes a variety of approaches such as use of stereoselective reactions, chiral auxilaries, chiral templates and asymmetric catalysis. The C-glycosidic analogues of galactosylated hydroxynorvaline and hydroxylysine were incorporated in glycopeptides from type II collagen and evaluated in T cell response assays. It was found that the T cells were stimulated by the C-glycopeptides, but that higher concentrations were required than for the native O-glycopeptide
1255

Fcγ Receptors in the Immune Response

Díaz de Ståhl, Teresita January 2001 (has links)
Circulating immune complexes play an important role in the modulation of antibody responses and in the pathogenesis of immune diseases. This thesis deals with the in vivo regulatory properties of antibodies and their specific Fc receptors. The immunosuppressive function of IgG is used clinically, to prevent rhesus-negative women from becoming sensitized to rhesus-positive erythrocytes from the fetus. The mechanism behind this regulation is poorly understood but involvement of a receptor for IgG, FcγRII, has been suggested. It is shown in this thesis that IgG and also IgE induce immunosuppression against sheep erythrocytes to a similar extent both in mice lacking all the known Fc receptors as in wild-type animals. These findings imply that antibody-mediated suppression of humoral responses against particulate antigens is Fc-independent and that the major operating mechanism is masking of epitopes. Immunization with soluble antigens in complex with specific IgG leads to an augmentation of antibody production. The cellular mechanism behind this control is examined here and it is found that the capture of IgG2a immune complexes by a bone marrow-derived cell expressing FcγRI (and FcγRIII) is essential. An analysis of the ability of IgG3 to mediate this regulation indicated that, in contrast, this subclass of IgG augments antibody responses independently of FcγRI (and FcγRIII). These findings suggest that distinct mechanisms mediate the enhancing effect of different subclasses of antibodies. Finally, the contribution of FcγRIII was studied in the development of collagen-induced arthritis (CIA), an animal model for rheumatoid arthritis in humans. It was discovered that while DBA/1 wild-type control mice frequently developed severe CIA, with high incidence, FcγRIII-deficient mice were almost completely protected, indicating a crucial role for FcγRIII in CIA. The results presented here help to understand how immune complexes regulate immune responses in vivo and show that Fc receptors for IgG, if involved, could be new targets for the treatment of immune complex-related disorders.
1256

Meals and Food in Older Women : Health Perceptions, Eating Habits, and Food Management

Gustafsson, Kerstin January 2002 (has links)
The aim was to describe and explore the food-related work and eating habits of older community-dwelling women, with Parkinson’s disease, rheumatoid arthritis or stroke or without these diseases. The major focus is on health perceptions, eating habits and meal support. A theoretical framework based on cultural and health theories was adopted. A total of 91 women between 64 and 88 years were visited in their homes, a food survey was performed consisting of a 24h recall and an estimated three-day food diary was introduced. Seventy-two of the women also took part in qualitative interviews with an ethnographic approach. Approximately one week later, another 24h recall was carried out at a second visit, or for the non-disabled women by telephone. The analyses revealed that many women were influenced by the prevailing health message and tried to eat a healthy diet. It was also important to them to enjoy their preferred foods, but this gave some women a bad conscience, while others perceived their usual foods as wholesome to eat. Health promotion for older women needs to incorporate the women’s own cultural context, their perceptions of food-related health, and their wish to adhere to their usual habits. Women with disease, frailty and who had become alone reported simplified food-related work and poor eating habits. However, management of these duties was highly valued, and women strove to cook by themselves as long as possible when disability became a threat. This resulted in a trend towards less nourishing cooked meals for women with disabilities. Thus, many women with these diseases living at home need support with their meals. This has to be planned in collaboration with the woman and build on her cultural values. The help must be performed with respect for the woman’s sense of order, be given sufficient time, and acknowledge her self-determination.
1257

Intra-articular Glucocorticoid Treatment : Efficacy and Side Effects

Weitoft, Tomas January 2005 (has links)
Intra-articular glucocorticoid injection therapy is frequently used to relieve symptoms of arthritis, but there is considerable variation in injection routines among physicians. One issue of debate concerns the importance of synovial fluid aspiration during the injection procedure. In the present randomised controlled study of patients with rheumatoid arthritis (RA), a significantly reduced risk for arthritis relapse was observed when arthrocentesis was included in the intra-articular injection procedure of the knee. Furthermore, there is no consensus about the post-injection regimes. Previous studies have shown beneficial effects of post-injection rest of the knee, but also injection routines for other joints often include such recommendations. The present randomised controlled trial showed that 48-hour rest in elastic orthosis after intra-articular injection in the wrist did not improve the outcome. Thus, the effect of post-injection rest varies between different joints. The improved treatment result of post-injection rest of the knee is supposed to be caused by retarded steroid resorption from the joint. In order examine the metabolic effects in cartilage, bone and the hypothalamic-piuitary-adrenal (HPA)-axis, resting and mobile RA patients were studied after intra-articular knee injections. Serum levels of the injected glucocorticoid, triamcinolone hexacetonide (THA), were analysed, as well as cartilage oligomeric matrix protein (COMP) as a marker of cartilage turnover, osteocalcin for bone formation and deoxypyridinoline for bone resorption. The HPA-axis was assessed using serum levels of cortisol and adrenocorticotropine hormone. The result showed a short term and reversible suppression of the HPA-axis and bone formation, whereas bone resorption was unaffected. No differences between mobile and resting patients were observed. In both groups reduction of COMP levels were seen, but these were significantly more pronounced in resting patients, suggesting a cartilage-protective effect. The THA levels increased similarly in both groups, indicating that rest did not affect glucocorticoid resorption. Consequently, another explanation for the beneficial effects of postinjection rest of knee synovitis should be considered. In the present material the incidence of infectious complications of intra-articular treatment was less than 1/12,000 injections. The findings in this thesis can be applied in the clinical practice and should be considered when new guidelines for intra-articular glucocorticoid therapy are created.
1258

Predictors of disease onset and progression in early rheumatoid arthritis : A clinical, laboratory and radiological study

Berglin, Ewa January 2006 (has links)
To diagnose rheumatoid arthritis (RA) during the early stages of the disease is often difficult. The disease course shows great inter-individual variation from mild, self-limiting to very severe destruc-tive disease with extra-articular manifestations. Early aggressive treatment with potentially toxic drugs has been shown to improve the long-term outcome. Thus, it is desirable to make an early reliable di-agnosis and to identify those patients who would benefit from being treated most aggressively. The aim of this thesis was to evaluate laboratory and clinically markers of inflammation as predic-tors of disease course, to compare dual-energy X-ray absorptiometry (DXA) and conventional radiog-raphy (CR) as measures of joint destruction and to investigate the significance of antibodies against cyclic citrullinated peptide (anti-CCP antibodies), rheumatoid factors (RFs) and HLA shared epitope (SE) alleles for the relative risk of future development of RA and as predictors of disease severity in patients with early RA. Patients with RA of recent onset are included in the early RA programme at the Department of Rheumatology, University Hospital, Umeå and are followed longitudinally. The prediction of markers of inflammation for bone loss and radiological outcome was analyzed in the first 43 patients recruited. Radiographs of hands and feet (Larsen score) and bone mineral density (BMD) in hands (DXA), were assessed at baseline, after 1 and 2 years. The disease activity was evaluated clinically and by labora-tory tests. Radiological damage increased significantly during the study and was particularly corre-lated with Larsen score at baseline. BMD in hands decreased significantly in postmenopausal women and the decrease was greater than in healthy matched controls. Radiological progression and bone loss in hands was retarded by an early response to therapy. In a case-control study within the Medical Biobank and the Maternity cohort of Northern Sweden, patients from the early RA programme were identified among blood donors from whom samples had been collected years before onset of symptoms. The prevalence of anti-CCP antibodies and RFs (IgA-RF, IgG-RF and IgM-RF) was investigated in samples from 83 individuals (pre-patients) and com-pared with matched controls. SE alleles were assessed in a sub-group of 59 individuals. Anti-CCP antibodies and RFs preceded onset of RA by several years and increased in prevalence closer to dis-ease onset. Anti-CCP antibodies and IgA-RF significantly predicted the onset of RA. The combination of anti-CCP antibodies and SE alleles was associated with a high relative risk for future development of RA. In a later co-analysis between the register of patients in the early RA programme (n=138) and the Medical Biobank and the Maternity cohort, 93 pre-patient samples were identified. The significance of SE alleles and of the presence of anti-CCP antibodies and RFs before and at disease onset for disease activity and severity was studied. Radiographs of hands and feet were assessed at baseline and after 2 years (Larsen score). The presence of anti-CCP antibodies in pre-patient samples and at baseline was associated with radiological damage, as was presence of all RFs at baseline. A higher titre of anti-CCP antibodies was associated with greater radiological progression. The titre was lowered by a therapeutic response. In multiple logistic regression analyses anti-CCP antibodies, IgA-RF, ESR and swollen joint count predicted greater radiological progression, whilst a therapeutic response predicted a lesser pro-gression. In conclusion, anti-CCP antibodies and IgA-RF are predictors for future onset of RA and for radio-logical destruction and progression. The combination of anti-CCP antibodies and SE alleles is associ-ated with a high relative risk for future RA. Therapeutic response decreases the radiological progres-sion and the bone loss in hands and lowers the titre of anti-CCP antibodies. Conventional radiography is a better measure of joint destruction than DXA.
1259

Chronic Obstructive Pulmonary Disease : Patients´ Perspectives, Impact of the Disease and Utilization of Spirometry

Arne, Mats January 2010 (has links)
The overall aim of this thesis was to describe subjects with chronic obstructive pulmonary disease (COPD) from different perspectives. Focus was on patients at the time of diagnosis, impact of the disease in comparison to other chronic diseases, factors associated with good health and quality of life (QoL), and diagnostic spirometry in clinical practice. Methods: Qualitative method, grounded theory, was used to analyse patients´ perspectives at the time of diagnosis in a primary care setting (n=10). Public health surveys in the general population were used to compare chronic diseases (n=10,755) and analyse factors associated with health outcomes in COPD (n=1,475). Medical records and spirometry reports, from primary and secondary care, were analysed to assess diagnosis of COPD in clinical practice (n=533). Results: In clinical practice, 70% of patients at the time of diagnosis of COPD lacked spirometry results confirming the diagnosis. Factors related to consequences of smoking, shame and restrictions in physical activity (PA) in particular, were described by patients at the time of diagnosis of COPD. In general subjects with COPD (84%), rheumatoid arthritis (74%) and diabetes mellitus (72%) had an activity level considered too low to maintain good health. In COPD, the most important factor associated with good health and quality of life was a high level of PA. Odds ratios (OR (95%CI)) varied from 1.90 (1.47-2.44) to 7.57 (4.57-12.55) depending on the degree of PA, where subjects with the highest PA level had the best health and QoL. Conclusions: Subjects with COPD need to be diagnosed at an early stage, and health professionals should be aware that feelings of shame could delay patients from seeking care and thus obtaining a diagnosis. The use of spirometry and the diagnostic quality should be emphasised. In patients with COPD greater attention should be directed on increasing the physical activity level, as patients with a low level of physical activity display worse health and quality of life.
1260

Development of diffraction enhanced computed tomography for imaging joints

2015 September 1900 (has links)
This research was inspired by a need to discover more refined technologies for imaging growing joints to facilitate research in childhood arthritis, which is among the most common chronic conditions of childhood. The objective of this project was to develop and test a new technology for imaging growing joints using diffraction enhanced imaging (DEI) combined with computed tomography (CT) using a synchrotron radiation source. DEI is a modality that derives contrast from x-ray refraction, extinction (an extreme form of scatter rejection), and absorption (as in conventional radiography). The ability to add to an image’s contrast from the refraction of x-rays, rather than that solely from absorption, generates more detailed visualization of soft tissue and of interfaces between tissues. Additionally, refraction-based imaging allows reduction of absorbed radiation dose by the sample tissue. For this research, stifle joints from four-week piglet joints were imaged by DEI-CT using the BioMedical Imaging and Therapy (BMIT) beamline at the Canadian Light Source (CLS) synchrotron facility. This new modality for imaging growing joints incorporated a novel feedback control to maintain precise alignment of the analyzer crystal, which is used to re- diffract the beam that passes through the object, throughout the scanning procedure. Results showed that high-resolution DEI-CT provided three-dimensional images of the bone and soft tissue of growing joints at a resolution on the order of microns. Fine detail within and between all joint structures and tissues, including striking detail of cartilage vasculature, a iii characteristic of growing but not mature joints, was demonstrated. This report documents for the first time that DEI combined with CT and using a synchrotron radiation source can generate more detailed images of intact, growing joints than is currently available from conventional imaging modalities. The development of this high resolution imaging system, which provides excellent contrast for both hard and soft tissues, fills an important gap in the suite of imaging modalities available for joint research, particularly during growth.

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