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Immunological self-tolerance is a state of the whole organism where deleterious responses are either avoided or regulated. Breaking of immunological tolerance will lead to autoimmune disease or chronic inflammatory conditions. T cell maturation in the thymus generates a peripheral T cell pool with an enormous TCR repertoire, from which specific T cells are selected and activated upon encounters wi
Most organisms on Earth live a life where they are exposed to multiple and variable threats. In order to maximise survival they need to be able to perceive and respond to these threats. Two common threats that crustacean zooplankton are faced with are predation and ultraviolet radiation (UVR). To cope with these threats zooplankton use different strategies such as diel vertical migration and the a
Left atrioventricular plane displacement (AVPD) has been shown to correlate well with left ventricular (LV) systolic function measured as ejection fraction (EF). AVPD has also been shown to be related to diastolic performance. Other factors related to AVPD include age, heart rate, LV and atrial dimensions, myocardial thickness, bodysurface, and afterload. In this thesis the left AVPD was studied i
The growth of short fatigue cracks deviates from the behaviour of long fatigue cracks even if subjected to the same nominal driving force. The influence from the microstructure is pronounced, while crack closure effects may not be that important as for longer cracks. The objective of this thesis is to study the local conditions for crack growth for two different short crack problems, and to develo
This thesis evaluates alterations in lipid metabolism and Kupffer cell morphology seen during total parenteral nutrition in healthy rats. During infusion of lipid emulsions, cholesterol and phospholipids accumulated in non-high density lipoproteins, while high density lipoproteins were enriched in triglycerides. Triglycerides also accumulated in hepatic tissue, and the activity of hepatic lipase
Estrogen receptors (ER) are expressed not only in classical target organs for estrogen like breast and uterus, but also in male reproductive system as well as in non-reproductive organs such as brain, liver and bone. The functions of ER are quite well known in reproductive organs but less information is available regarding their function in vascular tissue. The objective of this thesis was to inve
This thesis describes early inflammatory responses involving interactions between leukocytes and the endothelial lining of the blood vessel wall. An adhesion molecule, E-selectin, which is upregulated on interleukin-1 activated endothelium, was found to mediate rolling between leukocytes and endothelial cells in vivo. Immunohistochemistry revealed that E-selectin was preferentially expressed in ve
Competition between and within species has been one of the most studied concepts in ecology. In this thesis the aim was to test the idea of plant-microbial competition for N and, by studying this interaction, to gain a better understanding of different N processes in soil. The research carried out seeks to investigate plant-microbial competition for N based on the definition that competition only
Acute pancreatitis (AP) is a common disorder where underlying mechanisms for the local initiating events in the pancreas, the systemic dissemination of the inflammatory response and the remote organ dysfunction still are unclear. The aim of the present study was to further characterize the dynamics and sequence of the immune response in AP, and to determine the cellular origin of the initiating ev
Two putative cyclodextrinases (CDases) were amplified from two moderate thermophiles isolated in Iceland: Anoxybacillus flavithermus and Laceyella sacchari. They were cloned, expressed and characterized. The expression of the former was optimized in E. coli by using a solubility-enhancing tag, NusA, and tuning of inducer concentration in the expression strain Tuner(DE3). The CDases were optimally
A probabilistic framework used in studying collective decision making is the uncertain dichotomous choice model. The model is essentially characterized by two components: the organizational structure and the voting process. By organizational structure, we refer to a group composed of members with common objectives and who are tasked to choose one of the two given alternatives, one of which is assu
The influence of alcohol on bone metabolism, fracture and fracture healing was evaluated in men and male rats by measurements of bone mineral density (BMD), biochemical markers and biomechanical testings. Retrospectively, 199 male patients hospitalized for tibia shaft fractures were studied. Forty-nine were judged as problem drinkers. Abusers were more prone to sustain oblique fractures. The heal
In many species of birds juveniles migrate independently of experienced adults and thus have to rely on innate information about migratory routes and wintering area. This information is encoded as a set of inherited migratory directions and a timing schedule that provides information on when and how far to migrate. Apart from these remarkable behavioral adaptations, migration also requires several
The CD4+ T cells have an important role in inflammation. Based on the local cytokine milieu, these cells can differentiate into either a Th1 population promoting cellular immunity or Th2 population involved in humoral immunity. Th2 cells produce the anti-inflammatory cytokines IL-4 and IL-10, which might have a protective role in autoimmune diseases like rheumatoid arthritis (RA) and multiple scle
Translation is a central biological process, that is catalysed by a machinery consisting of RNA and protein. In this thesis three different protein components of the bacterial protein synthesis system have been structurally studied. Ribosome recycling factor (RRF) is essential for the recycling step of the translation cycle, elongation factor SelB is a specialised elongation factor needed for co-t
Overall the aim has been to characterise the in vitro upregulation of the 5-hydroxytryptamine 1B/1D (5-HT(1B/1D)) and endothelin (ET) receptors in the cerebral circulation as well as demonstrating phenotypic changes in a pathophysiological model mimicking subarachnoid haemorrhage. The first part describes receptor upregulation using organ culture of whole vessel segments from both rat and man. The
Natural disturbance is an important driving force of community dynamics in many forest types around the globe. Understanding spatial and temporal properties of disturbance events in the present and in the past is important in formulating the nature conservation strategies as well as for the modeling of climate and human impacts on forest vegetation. In this thesis I studied wind and fire disturban
The immune pathology and MHC association of chronic arthritis was studied in three rat models for reumatoid arthritis (RA). Susceptible rat strains develop a T cell dependent chronic disease after immunization with rat collagen type II (CII). The LEW rat does not develop arthritis after immunization with rat CII, but a heterologous immune response to pepsin can break the tolerance to CII and rende
A considerable part of all chemistry in nature and in industry occurs in solvents. Sol- vents affect both the interactions and the reactions of the particles immersed in them. The work in this thesis concerns the properties of ionic and polar solvents, as well as the interactions between solutes and/or dispersed particles. Molecular simulations and simple approximate theories were used to study th
The aim of this thesis is to study the life-changing processes necessary when a person is faced with the demands caused by chronic illness or disability. As subjects for the study, women with chronic pain (fibromyalgi and myofascial pain syndrome), were chosen. Eighteen women active in working life were interviewed on two occasions, with an interval of two months. The women have been living with t
