Dementia and Intersectionality: Exploring the experiences of older people with dementia and their significant others

The aim of this thesis is to demonstrate that new and varied views of dementia surface when the concept of intersectionality is applied to dementia research; and that these perspectives pose challenges to our assumptions about what it is like to have dementia. Grounded theory research from a feminist and anti-oppression perspective was undertaken to explore the question of the relationships between older people‘s experiences of dementia and the intersections of gender, class, ‘race’, and ethnicity. During nine months of field research in Canada, interviews, participant observation, photography, and focus groups were undertaken with eight older people with dementia and their significant others. The participants ranged from multiply marginalized to multiply privileged on the basis of their ‘race’, ethnicity, gender, and class. The grounded theory arising from this research explains the complex nature of the relationships between the subjective experiences of older people living with dementia and the intersections of ethnicity, ‘race’, class, and gender. I argue that there is a connection between social location and lived experiences of dementia; and that these relationships can be observed across and within the categories of experiencing, othering, and theorising. Experiencing captures the diversity of older people’s experiences of dementia, which range from ‘not a big deal’ to ‘a nuisance’ to ‘hellish’: these views are associated with social location, with the multiply privileged older people holding the most negative views of dementia and the multiply marginalized older people dismissing the significance of dementia. Othering refers to the marginalisation to which people with dementia are subject: it is shown to be a marked feature of life with dementia and to be connected to social location, with the multiply privileged people being othered more often as a result of their dementia status; the more marginalised participants demonstrating resilience (as an acquired characteristic); and all being subject to both othering practices and enabling behaviours enacted by members of their social worlds, such as their significant others. The theorising category refers to people with dementia being active meaning makers who theorise about dementia: the outcome of this intellectual activity is shown to be related to social location, with the most privileged participants being the only ones to view dementia as a brain disease; and all others making strategic use of the normal aging theory to avoid marginalisation due to dementia. The result of the theorising done by older people with dementia is a dialectical theory of dementia that positions dementia as a bio-psycho-social phenomenon, disrupts the false dichotomy between normal and pathological, and integrates emic and etic perspectives on dementia

Looking beyond endotoxin: a comparative study of pyrogen retention by ultrafilters used for the preparation of sterile dialyis fluid

Sterile single-use ultrafilters are used in dialysis for the preparation of the substitution fluid given to patients undergoing dialysis treatments with high convective fluid removal. The retention of pyrogenic agents by the ultrafilters is crucial to avoiding inflammatory responses. The performance of a new single-use ultrafilter (NUF) with a positively charged flat sheet membrane of relatively small membrane area and large pore size was compared to a reference ultrafilter (RUF) with a hollow fiber membrane. Filter performance was tested with various pyrogen-contaminated dialysis fluids by direct pyrogen quantification and by measuring inflammatory responses in cell-based bioassays. The NUF completely retained oligodeoxynucleotides (ODN), whereas the RUF was fully permeable. Both filters tended to decrease biological activity of DNA in filtered bacterial lysates. The NUF reduced lipopolysaccharides (LPS) and LPS-induced biological activity by 100%, whereas the RUF produced filtrates with low but detectable levels of LPS in most cases. Peptidoglycans (PGN) were fully retained both by the NUF and the RUF. The new ultrafilter retained biologically active ODN, which has not yet been described for any other device used in dialysis, and it showed better or equal retention of LPS and PGN even with a smaller membrane surface and larger pore size

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Dementia and intersectionality : exploring the experiences of older people with dementia and their significant others

The aim of this thesis is to demonstrate that new and varied views of dementia surface when the concept of intersectionality is applied to dementia research; and that these perspectives pose challenges to our assumptions about what it is like to have dementia. Grounded theory research from a feminist and anti-oppression perspective was undertaken to explore the question of the relationships between older people‘s experiences of dementia and the intersections of gender, class, ‘race’, and ethnicity. During nine months of field research in Canada, interviews, participant observation, photography, and focus groups were undertaken with eight older people with dementia and their significant others. The participants ranged from multiply marginalized to multiply privileged on the basis of their ‘race’, ethnicity, gender, and class. The grounded theory arising from this research explains the complex nature of the relationships between the subjective experiences of older people living with dementia and the intersections of ethnicity, ‘race’, class, and gender. I argue that there is a connection between social location and lived experiences of dementia; and that these relationships can be observed across and within the categories of experiencing, othering, and theorising. Experiencing captures the diversity of older people’s experiences of dementia, which range from ‘not a big deal’ to ‘a nuisance’ to ‘hellish’: these views are associated with social location, with the multiply privileged older people holding the most negative views of dementia and the multiply marginalized older people dismissing the significance of dementia. Othering refers to the marginalisation to which people with dementia are subject: it is shown to be a marked feature of life with dementia and to be connected to social location, with the multiply privileged people being othered more often as a result of their dementia status; the more marginalised participants demonstrating resilience (as an acquired characteristic); and all being subject to both othering practices and enabling behaviours enacted by members of their social worlds, such as their significant others. The theorising category refers to people with dementia being active meaning makers who theorise about dementia: the outcome of this intellectual activity is shown to be related to social location, with the most privileged participants being the only ones to view dementia as a brain disease; and all others making strategic use of the normal aging theory to avoid marginalisation due to dementia. The result of the theorising done by older people with dementia is a dialectical theory of dementia that positions dementia as a bio-psycho-social phenomenon, disrupts the false dichotomy between normal and pathological, and integrates emic and etic perspectives on dementia.EThOS - Electronic Theses Online ServiceOverseas Research Student Award Scheme : University of Stirling : Alzheimer Society of OntarioGBUnited Kingdo

Medium Cut-Off (MCO) Membranes Reduce Inflammation in Chronic Dialysis Patients—A Randomized Controlled Clinical Trial

Background To increase the removal of middle-sized uremic toxins a new membrane with enhanced permeability and selectivity, called Medium Cut-Off membrane (MCO-Ci) has been developed that at the same time ensures the retention of albumin. Because many middle-sized substances may contribute to micro-inflammation we hypothesized that the use of MCO-Ci influences the inflammatory state in hemodialysis patients. Methods The randomized crossover trial in 48 patients compared MCO-Ci dialysis to High-flux dialysis of 4 weeks duration each plus 8 weeks extension phase. Primary endpoint was the gene expression of TNF-α and IL-6 in peripheral blood mononuclear cells (PBMCs), secondary endpoints were plasma levels of specified inflammatory mediators and cytokines. Results After four weeks of MCO-Ci the expression of TNF-α mRNA (Relative quantification (RQ) from 0.92 ± 0.34 to 0.75 ± 0.31, -18.5%, p<0.001)-α and IL-6 mRNA (RQ from 0.78 ± 0.80 to 0.60 ± 0.43, -23.1%, p<0.01) was reduced to a significantly greater extent than with High-flux dialyzers (TNF mRNA-RQ: -14.3%; IL-6 mRNA-RQ: -3.5%). After retransformation of logarithmically transformed data, measurements after MCO were reduced to 82% of those after HF (95% CI 74%–91%). 4 weeks use of MCO-Ci resulted in long- lasting change in plasma levels of several cytokines and other substances with a significant decrease for sTNFR1, kappa and lambda free light chains, urea and an increase for Lp-PLA2 (PLA2G7) compared to High-flux. Albumin levels dropped significantly after 4 weeks of MCO dialysis but increased after additional 8 weeks of MCO dialysis. Twelve weeks treatment with MCO-Ci was well tolerated regarding the number of (S)AEs. In the extension period levels of CRP, TNF-α-mRNA and IL-6 mRNA remained stable in High-flux as well as in MCO-Ci. Conclusions MCO-Ci dialyzers modulate inflammation in chronic HD patients to a greater extent compared to High-flux dialyzers. Transcription of pro-inflammatory cytokines in peripheral leukocytes is markedly reduced and removal of soluble mediators is enhanced with MCO dialysis. Serum albumin concentrations stabilize after an initial drop. These results encourage further trials with longer treatment periods and clinical endpoints

Assessment of the association between increasing membrane pore size and endotoxin permeability using a novel experimental dialysis simulation set-up

Background: Membranes with increasing pore size are introduced to enhance removal of large uremic toxins with regular hemodialysis. These membranes might theoretically have higher permeability for bacterial degradation products. In this paper, permeability for bacterial degradation products of membranes of comparable composition with different pore size was investigated with a new in vitro set-up that represents clinical flow and pressure conditions. Methods: Dialysis was simulated with an AK200 machine using a low-flux, high-flux, medium cut-off (MCO) or high cut-off (HCO) device (n = 6/type). A polyvinylpyrrolidone-solution (PVP) was recirculated at blood side. At dialysate side, a challenge solution containing a filtrated lysate of two water-borne bacteria (Pseudomonas aeruginosa and Pelomononas saccharophila) was infused in the dialysate flow (endotoxin >= 4EU/ml). Blood and dialysate flow were set at 400 and 500 ml/min for 60 min. PVP was sampled before (PVPpre) and after (PVPpost) the experiment and dialysate after 5 and 55 min. Limulus Amebocyte Lysate (LAL) test was performed. Additionally, samples were incubated with a THP-1 cell line (24 h) and IL-1 beta levels were measured evaluating biological activity. Results: The LAL-assay confirmed presence of 9.5 +/- 7.4 EU/ml at dialysate side. For none of the devices the LAL activity in PVPpre vs. PVPpost was significantly different. Although more blood side PVP solutions had a detectable amount of endotoxin using a highly sensitive LAL assay in the more open vs traditional membranes, the permeability for endotoxins of the 4 tested dialysis membranes was not significantly different but the number of repeats is small. None of the PVP solutions induced IL-1 beta in the THP-1 assay. Conclusions: A realisitic in vitro dialysis was developed to assess membrane translocation of bacterial products. LAL activity on the blood side after endotoxin exposure did not change for all membranes. Also, none of the PVPpost solutions induced IL-1 beta in the THP-1 bio-assay

Donor ionization in size controlled silicon nanocrystals: The transition from defect passivation to free electron generation

We studied the photoluminescence spectra of silicon and phosphorus co-implanted silica thin films on (100) silicon substrates as a function of isothermal annealing time. The rapid phase segregation, formation, and growth dynamics of intrinsic silicon nanocrystals are observed, in the first 600 s of rapid thermal processing, using dark field mode X-TEM. For short annealing times, when the nanocrystal size distribution exhibits a relatively small mean diameter, formation in the presence of phosphorus yields an increase in the luminescence intensity and a blue shift in the emission peak compared with intrinsic nanocrystals. As the mean size increases with annealing time, this enhancement rapidly diminishes and the peak energy shifts further to the red than the intrinsic nanocrystals. These results indicate the existence of competing pathways for the donor electron, which depends strongly on the nanocrystal size. In samples containing a large density of relatively small nanocrystals, the tendency of phosphorus to accumulate at the nanocrystal-oxide interface means that ionization results in a passivation of dangling bond (Pb -centre) type defects, through a charge compensation mechanism. As the size distribution evolves with isothermal annealing, the density of large nanocrystals increases at the expense of smaller nanocrystals, through an Ostwald ripening mechanism, and the majority of phosphorus atoms occupy substitutional lattice sites within the nanocrystals. As a consequence of the smaller band-gap, ionization of phosphorus donors at these sites increases the free carrier concentration and opens up an efficient, non-radiative de-excitation route for photo-generated electrons via Auger recombination. This effect is exacerbated by an enhanced diffusion in phosphorus doped glasses, which accelerates silicon nanocrystal growth

Universal architecture of bacterial chemoreceptor arrays

Chemoreceptors are key components of the high-performance signal transduction system that controls bacterial chemotaxis. Chemoreceptors are typically localized in a cluster at the cell pole, where interactions among the receptors in the cluster are thought to contribute to the high sensitivity, wide dynamic range, and precise adaptation of the signaling system. Previous structural and genomic studies have produced conflicting models, however, for the arrangement of the chemoreceptors in the clusters. Using whole-cell electron cryo-tomography, here we show that chemoreceptors of different classes and in many different species representing several major bacterial phyla are all arranged into a highly conserved, 12-nm hexagonal array consistent with the proposed “trimer of dimers” organization. The various observed lengths of the receptors confirm current models for the methylation, flexible bundle, signaling, and linker sub-domains in vivo. Our results suggest that the basic mechanism and function of receptor clustering is universal among bacterial species and was thus conserved during evolution