| 4631. |
- Permanto, Stefan, 1969
(författare)
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The Elders and the Hills: Animism and Cosmological Re-Creation among the Q'eqchi' Maya in Chisec, Guatemala
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on fieldwork conducted in the municipality of Chisec in the department of Alta Verapaz in Guatemala. Within the context of post-war Maya cultural emergence and the recent introduction of non-indigenous elements this study examines the cosmological notions and ritual practices among a group of elderly Q’eqchi’ men and women. The main motive for this endeavor is the expressed concern of the elders that the younger generations of today are diverting from what the elders consider to be the traditional ways of life that are inherited from their ancestors. The elders fear that if traditional cosmological notions are lost it may eventually wreak havoc in the world. Therefore, these elders have come together not only to narrate and share their vital knowledge amongst themselves but also to transmit it to future generations. Theoretically, the thesis is inspired by the recent re-definition of the concept of animism within anthropological theory. Stripping the concept of earlier evolutionary notions that debunks it as only irrational understandings of the world, the cosmological notions and ritual practices of the Q’eqchi’ elders are taken at face value and approached as ways of being-in-the-world. While this ‘new’ animism has been deployed in studies among indigenous peoples from Amazonia to South East Asia it has been conspicuously absent in Mesoamerica. By applying the new perspectives on animism to the cosmology of the Q’eqchi’ elders this study contributes not only to the general body of anthropological studies of animism and indigenous societies but expands it to include the Maya region. Since culture is neither static nor homogeneous the work and ambition of the elders to preserve and transmit their inherited knowledge inevitably gives fuel to a process of rediscovering and re-creating their cosmological roots and ritual practices: a cosmology the elders assert is crucial not only for human and non-human wellbeing but also for a sustainable ecology and cosmic equilibrium.
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| 4632. |
- Pernber, Zarah, 1969
(författare)
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Expression of sulfatide in rodent CNS - not only restricted to myelin
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sulfatide is an acidic glycosphingolipid and a component of myelin in the nervous system proposed to be involved in maintenance of the myelin structure and thereby its function. Sulfatide is also a commonly used marker for detection of oligodendrocyte progenitor cells in cultures as well as in tissues. Previous studies have, however, indicated that sulfatide might also be expressed in non-myelin-forming cells in the brain. The aim of this study was to elucidate the existence of sulfatide beyond oligodendrocytes in the CNS by combining immunohistochemistry and lipid analyses. Sulfatide expression was analysed in primary astrocyte cultures and in adult rodent brain tissue. To improve detection of sulfatide-positive cells in tissues, the detergent treatment was minimised to avoid extraction of the glycosphingolipid antigen and confocal microscopy was used for examination. In primary cultures, a minor population of sulfatide-positive astrocytes was detected immunohistochemically and the amount of sulfatide was quantified by lipid analyses. Sulfatide was located intracellularly in these astrocytes, in contrast to the cell plasma membrane association and external exposure in myelin. Subpopulations of sulfatide-positive astrocytes were also found in vitro, in rat and mouse brain tissue. Moreover, selected neurons expressed sulfatide in the investigated brain areas; cerebral cortex, hippocampus and cerebellum. An arylsulfatase A (ASA) null mutation mouse model, unable to degrade sulfatide, was used to facilitate the detection of sulfatide-expressing cells. This tissue showed an extensive accumulation of sulfatide in neurons, which indicates a higher turnover of sulfatide in neurons compared to astrocytes. Metachromatic leukodystrophy (MLD) is a human disease caused by defects in the ASA enzyme followed by extensive sulfatide accumulation in white matter and demyelination. Neurological symptoms are the most pronounced, while adult patients have initial psychiatric symptoms that have raised the question if other cells are involved in the progression of the disease. The findings in this study indicate that neurons might be those other cells. In conclusion, this thesis provides evidence for the expression of the myelin-associated glycosphingolipid - sulfatide - also in astrocytes and neurons in adult rodent brain. The role of sulfatide in the various cells remains an open question but its existence supports multipotential function, which might be considered to contribute to the symptoms of MLD.
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| 4633. |
- Pernbro, Fredrik
(författare)
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Coagulation in paediatric cardiac surgery
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Surgical correction of congenital heart defects has a profound effect on the coagulation of the patients during and immediately after surgery. The aim of this thesis was to increase the knowledge of this effect, and to add to the work of establishing methods for treating this coagulopathy. Methods: Study I investigates the platelet response to paediatric cardiac surgery by analysis of platelet count and platelet aggregation measured with multiple electrode aggregation (MEA) before, during and after surgery. Study II measures the in vitro potency of the platelet inhibitor ticagrelor by measuring platelet aggregation using light transmission aggregometry and MEA. Study III compares MEA with a vasodilator activated phosphoprotein assay (VASP) before and after cardiac surgery. Study IV examines the coagulation in children with preoperative cardiac failure using rotational thromboelastometry. Study V is a method description of an ongoing study where patients are randomized to platelets or fibrinogen concentrate as the primary treatment of coagulopathy after cardiac surgery. Results: Platelet count and aggregation fall significantly during cardiac surgery, and impaired aggregation increases the risk of blood transfusion. The potency of ticagrelor in vitro does not vary with patient age. The correlation between MEA and VASP is poor. MEA results are similar in children with cardiac defects and healthy children. Preoperative cardiac failure does not have a significant impact on thromboelastometry results. Conclusions: Cardiac surgery in certain paediatric populations causes significant coagulopathy. Impaired platelet aggregation increases the risk of transfusion. Cardiac failure does not cause coagulopathy in infants. Ticagrelor potency is similar in patients of different ages.
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| 4634. |
- Persdotter, Josefin, 1985
(författare)
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Menstrual dirt - An exploration of contemporary menstrual hygiene practices in Sweden
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Menstrual Dirt is a sociological study of how some aspects of menstruation come into being as dirty phenomenon, both in material and symbolic terms. Through engaging with a variety of empirical material Persdotter explores the everyday details of menstrual hygiene practices: how people roll their used pads, dispose their menstrual waste, wash their bloody genitals, change and clean their menstrual cups, clean toilets, and wash dirty clothes and carpets, and much more. With a theoretical basis in Mary Douglas’ arguments surrounding dirt as symbolic pollution, Persdotter explores the symbolic underpinnings of menstrual pollution, while also exploring the materiality and sensoriality of menstrual dirt, as well as adding a focus on the personal and emotional consequences of dirt and pollution. Persdotter employs primarily qualitative research methods, but the empirical material utilized in the study includes both in-depth interviews (12 interviewees) as well as survey data (445 respondents), and documents, commercials, online discussions, and de-scription of selected menstrual technologies. The thesis focuses on two specific technologies: the disposable pad and the reusable cup. The results showcase how everyday practices and technologies take part in the (re)enactment of ideas of menstrual pollution as well as material, sensory and emotional experiences of menstrual dirt. The thesis elaborates on these processes in four analytical chapters. Two revolve around the pad and explore dirt and pollution in relation to wearing the pad, and in relation to disposing of a used pad. Two revolve around the cup and explore the cup as a dirty and/or polluted object in itself, and the practice of changing (exerting, emptying, reinserting) as a practice that can make other objects dirty. Through using analytical tools from Science and Technology Studies, this thesis provides insights on the many heterogeneous actors and factors that take part in making menstruation into a matter of dirt and/or pollution. It explores technological, material and embodied aspects of that which critical menstruation scholarship often have regarded as merely social. This thesis adds to Critical Menstruation Studies also in shedding light on how pollution-beliefs, concealment imperatives and stigmatization of menstruation come into being in everyday practices. Through studying a Swedish context, it makes visible how a polluted status of menstruation can come into being in a Western society with a comparatively high level of gender equality and menstrual activism. Moreover, this research contributes to sociological explorations on dirt, and expands on the ways in which dirt can be utilized as an analytical tool, as well as facilitate greater understanding of the world around us, as well as exemplifying how exploring the seemingly trivial and inconsequential can make visible invisible how gendered inequalities are maintained and reaffirmed. Persdotter argues that exploring makings of menstrual pollution and dirt offers a sociological opportunity to make visible naturalized, routinized and trivialized practices and technologies in our everyday lives, and opening them up as more problematic, less given and more possible to change.
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| 4635. |
- Persson, Anita, 1971
(författare)
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Echocardiographic assessment and B-type natriuretic peptide for risk evaluation in acute coronary syndromes
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Acute coronary syndromes (ACS) is one of the most common causes of emergency medical care and the single most common cause of death in Sweden in both men and women. Despite a significant improvement in survival in the acute phase, the frequency of rehospitalization and death in subsequent years is unacceptably high. An estimation of future risk should therefore be a central part of the care of patients with ACS. Echocardiography for the evaluation of left ventricular (LV) function has become an important component in risk assessment. Further, the usefulness of various biochemical variables has been recognized and B-type natriuretic peptide (BNP) has been proven to be an important prognostic marker among patients with heart failure (CHF) and recently also in ACS. The aim of this thesis was to assess whether the incorporation of BNP and Doppler echocardiographic variables in risk stratification strategies in patients with ACS can improve the prediction of mortality and rehospitalization for CHF during long-term follow-up. The study included consecutive patients with ACS who received coronary care at Sahlgrenska University Hospital from September 1995 to March 2001. Clinical variables were collected during hospitalization, blood for the determination of BNP was sampled in the acute phase and a Doppler echocardiographic examination was performed. The echocardiographic 4-chamber view and Doppler curves were saved digitally or digitized and a range of systolic and diastolic variables, which reflect cardiac structure and function, were calculated. Patients were followed prospectively for a maximum of 110 months with regard to death and rehospitalization due to CHF. We found that BNP was significantly higher in deceased patients than in those who survived. BNP provided prognostic information, even when adjusting for Killip class >1, age and LV ejection fraction (LVEF), and also among patients without clinical evidence of CHF (Killip class 1). The presence of significant mitral regurgitation, low LVEF and increased levels of BNP were all independently associated with death, while rehospitalization for CHF was predicted by mitral regurgitation and LVEF. In a multivariate analysis, the LV volume index in systole (LVVIs) and the ratio of maximum systolic and diastolic pulmonary venous flow velocities (PV-s/d) were associated with all-cause mortality, cardiovascular mortality and rehospitalization due to CHF. Patients with a restrictive LV filling pattern had a poorer prognosis than those with normal filling and this diastolic abnormality remained a significant predictor of outcome even after adjustment for BNP and clinical risk factors, as assessed by the GRACE risk score. Further, additional prognostic information was provided by the LV outflow tract velocity integral (LVOT-VTI), LVEF and PV-s/d ratio. In conclusion, our results indicate that BNP, as well as a restrictive filling pattern, mitral regurgitation and other Doppler echocardiographic variables, such as LVOT-VTI, LVVIs, LVEF and PV-s/d ratio, provide prognostic information on long-term survival and rehospitalization due to CHF in patients with ACS, over and above clinical risk factors. For this reason, both information from a single echocardiographic view and BNP levels appear to be useful tools in the identification of high-risk ACS patients. Further studies are needed to clarify exactly how these risk markers should be used in the clinical routine.
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| 4636. |
- Persson, Annelie, 1977
(författare)
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Hyperoxia avoidance and aggregation behavior in C. elegans
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Living in the soil, C. elegans can move in three dimensions in search for food. To navigate, it partly uses oxygen levels as a description of its habitat. Oxygen tension may indicate presence of microbial food and location with respect to the surface, where oxygen is 21%. The N2 groups of C. elegans strains differ in their oxygen responses from other strains of this species collected in the wild. This difference is due to a polymorphism in the NPY receptor homologe, NPR-1. The result is two distinct feeding strategies; solitary feeding and feeding in groups (aggregation). NPR-1 antagonizes hyperoxia avoidance on food and N2-like strains, carrying a gain of function mutation in the receptor, feed alone and do not respond strongly to changes in ambient oxygen. In contrast, strains carrying the ancestral form of the receptor, NPR-1 215F, exhibit robust hyperoxia avoidance. These animals aggregate on food, at least in part because animals create a low oxygen environment as they form groups. In paper I we examined how hyperoxia avoidance can trigger aggregation. We showed that when animals encounter a rise in oxygen they initiate a reversal and turn. We showed that similar behaviors direct the animal to stay in an aggregate, and that aggregated animals create a sharp oxygen gradient. We further showed that soluble guanylate cyclases, expressed in the body cavity neurons, and TRPV channels expressed in the nociceptive neurons ASH and ADL, regulate these behaviors. ---text removed from public version--- In paper III we showed that a polymorphic locus, encoding the neuroglobin glb-5, regulates hyperoxia avoidance. The ancestral allele, glb-5(Haw), acts in the body cavity neurons and tunes the dynamic range of these neurons to a narrow range close 21% oxygen. ---text removed from public version--- The data presented in this thesis thus provide novel insights into oxygen sensing in a metazoan, and highlight how oxygen responses promote aggregation behavior of a nematode.
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| 4637. |
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| 4638. |
- Persson, Anders I., 1973
(författare)
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Opioids regulate proliferation of neural progenitors. A study on the effects of opioids on adult rat hippocampal progenitors in vitro and in vivo
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The opioid receptors were among the first pharmacologically described brain receptors. These opioid receptors have thereafter been shown to mediate effects on proliferation and differentiation in both the embryonal and adult central nervous system. The aim of this thesis was to investigate if cultured hippocampal progenitors from the adult rat brain expressed opioids and opioid receptors and to investigate a possible regulation by opioids on proliferation, differentiation and gene expression in these cultures. Furthermore, we wanted to extend the results and investigate if endogenous opioids regulated hippocampal proliferation in vivo by using opioid receptor antagonists in both non-running and voluntary running rats, a situation associated with increased levels of endogenous opioids. Hippocampal progenitors were found to release b-endorphin that bound to mu- (MOR) and delta- (DOR) but not kappa- (KOR) opioid receptors in vitro. Incubation with MOR or DOR antagonists reduced proliferation whereas stimulation with b-endorphin increased proliferation in these cultures, respectively. The opioid-induced proliferation involved both intracellular calcium and phosphatidylinositol 3-kinase that stimulated phosphorylation of mitogen-activated protein kinase (MAPK). Incubation with naloxone for ten days increased neurogenesis and reduced astrogliogenesis and oligodendrogenesis whereas stimulation with b-endorphin increased oligodendrogenesis but had no effect on astrogliogenesis. Using cDNA arrays, the levels of endogenous opioids were found to regulate gene expression for several cell cycle and oligodendrocyte-specific proteins. Stimulation with b-endorphin also increased Id1, but not Id3 mRNA levels. Down-regulation of Id1 protein using antisense oligonucleotides was suggested to antagonize the opioid-induced oligodendrogenesis.Using bromodeoxyuridine (BrdU), we observed a five-fold increase in hippocampal proliferation after nine days of wheel running in spontaneously hypertensive rats, a rat strain known to run voluntary. This increased BrdU labelling was reduced by peripheral administration of a preferential MOR, but not a DOR antagonist. In non-running rats, MOR and DOR antagonists increased hippocampal proliferation. In non-running, but not in running rats, the opioid receptor antagonists reduced adrenal gland weights and plasma levels of corticosterone. This stress hormone is known to reduce hippocampal neurogenesis. Running rats had three-fold higher levels of hippocampal Met-enkephalin-Arg-Phe levels compared to non-running rats, indicating increased opioid activity in hippocampus during running. These findings demonstrate that the levels of endogenous opioids, acting on MORs and DORs, regulate proliferation of adult rat hippocampal progenitors both in vitro and in vivo. Endogenous opioids were also shown to regulate differentiation and gene expression in cultures of hippocampal progenitors. Finally, we show that exercise robustly increases proliferation of hippocampal progenitors and that such an effect is partly mediated by endogenous opioids.
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| 4639. |
- Persson, Anna, 1986
(författare)
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Numerical Analysis of Evolution Problems in Multiphysics
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis we study numerical methods for evolution problems in multiphysics. The term multiphysics is commonly used to describe physical phenomena that involve several interacting models. Typically, such problems result in coupled systems of partial differential equations. This thesis is essentially divided into two parts, which address two different topics with applications in multiphysics. The first topic is numerical analysis for multiscale problems, with a particular focus on heterogeneous materials, like composites. For classical finite element methods such problems are known to be numerically challenging, due to the rapid variations in the data. One of our main goals is to develop a numerical method for the thermoelastic system with multiscale coefficients. The method we propose is based on the localized orthogonal decomposition (LOD) technique introduced in Målqvist and Peterseim (Math Comput 83(290):2583-2603, 2014). This is performed in three steps, first we extend the LOD framework to parabolic problems (Paper I) and then to linear elasticity equations (Paper II). Using the theory developed in these two papers we address the thermoelastic system (Paper III). In addition, we aim to extend the LOD framework to differential Riccati equations where the state equation is governed by a multiscale operator. The numerical solution of such problems involves solving many parabolic equations with multiscale coefficients. Hence, by applying the method developed in Paper I to Riccati equations the computational gain may be significantly large. In this thesis we show that this is indeed the case (Paper IV). The second part of this thesis is devoted to the Joule heating problem, a coupled nonlinear system describing the temperature and electric current in a material. Analyzing this system turns out to be difficult due to the low regularity of the nonlinear term. We overcome this issue by introducing a new variational formulation based on a cut-off functional. Using this formulation, we prove (Paper V) strong convergence of a large class of finite element methods for the Joule heating problem with mixed boundary conditions on nonsmooth domains in three dimensions.
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| 4640. |
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