Filtyp
Until recently, the islets of Langerhans were thought to harbour four main cell types characterised with respect to principal hormone product. Here we show that the novel hormone ghrelin is expressed in a fifth islet cell type, the islet ghrelin cell, in humans and rodents. The cells are developmentally regulated in that they are numerous around birth and fewer in the adult. The islet ghrelin cell
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
Plant phenology exerts major influences on carbon, water, and energy exchanges between atmosphere and ecosystems, provides feedbacks to climate, and affects ecosystem functioning and services. Great efforts have been spent in studying plant phenology over the past decades, but there are still large uncertainties and disputations in phenology estimation, trends, and its climate sensitivities. This
Systemic sclerosis (SSc) is a connective tissue disease with a highly variable prognosis. Since new treatment strategies are emerging, there is a need for prognostic markers in order to help allocate patients to the optimal treatment. When comparison is made to the general population, there is an increased mortality rate in this study, both in the series as a whole and in the subgroups of men and
As a cancer grows it will, at a certain stage of disease progression, start spreading in the body. For several types of cancer this spreading will first occur through the lymphatic system and the first place where metastatic cell will be encountered is the first lymph node that drains the area where the tumor is located. This lymph node is defined as the sentinel lymph node (SLN). By analyzing the
This thesis deals with Lennart Hellsing's works, and especially his texts for small children, from 1945 to 2000. In an introductory survey the oral transmission of literature is discussed in relation to orality and literacy. The presupposition is that there are similarities between oral culture and texts for the very young. Hellsing's production is surveyed along with his position as a poet, his i
Short high-frequency electromagnetic pulses, also referred to as wavelets, are considered for use in various short-range impulse based ultra-wideband applications, such as communication, imaging, radar, spectroscopy, and localization. This thesis investigates field-effect and tunneling based semiconductor devices and their operation in millimeter-wave (mm-wave) impulse transceivers. The main resea
Bacterial adhesion to the bladder mucosa is a critical step for the establishment of Escherichia coli bacteriuria. The P-fimbriae, encoded by the pap gene cluster, are considered as virulence factors but the mechanisms have been debated. This study defined the roles for P fimbriation during the early colonization of the human urinary tract. Patients with recurrent UTI were first subjected to deli
