Sökresultat

Filtyp

Din sökning på "swedish" gav 94058 sökträffar

The complex world of proteins: Structure, function, and oligomerization of frataxin

Patients suffering from the deadly progressive neurodegenerative disease Friedreich's ataxia have reduced levels of expression of the protein frataxin. Yeast frataxin has been extensively studied in vitro, and has been shown to deliver iron to heme and iron-sulfur cluster biosynthesis, as well as to oligomerize in the presence of iron. In this dissertation metal-dependent oligomerization of fratax

The immunomodulatory properties of C-Med 100 an extract of the plant Uncaria tomentosa

Extracts from the bark of the vine Uncaria tomentosa have anti-inflammatory, antiviral, antimutagenic and antioxidant effects. In this study, we evaluate the effects of an Uncaria tomentosa extract, denoted C-Med 100, on the cellular level of the immune system both in vivo and in vitro. Our results indicated that lymphocytes had significantly prolonged half life after in vivo supplementation with

Pancreatic Growth and Secretion. An Experimental Study on Growth Factors in Rat and Mouse

The pancreas is a central organ in the digestion of food as well as in glucose metabolism. Its two major functions are exocrine and endocrine secretion. These are meticulously regulated processes that depend on hormonal response to gastrointestinal contents and blood glucose levels through feedback mechanisms, but also to the status of pancreas in health and diseases. The present thesis aimed at f

The upper gastrointestinal tract in chronic alcoholics

Background: Gastrointestinal symptoms such as dyspepsia, diarrhoea, and nausea are often seen in alcoholics. The causes are not clear. The stomach and upper small intestine are exposed to high alcohol concentrations. Yet, the majority of alcohol abusers do not exhibit macroscopic abnormalities at upper gastrointestinal endoscopy, although histological and electron microscopic (SEM) changes have be

Transvascular fluid exchange with application to the brain. An experimental study in cat skeletal muscle and brain.

This study evaluated transcapillary fluid exchange in the cat brain and in a cat skeletal muscle enclosed in a plethysmograph. A method for determination of capillary permeability (capillary filtration coefficient and reflection coefficient) and effects of transcapillary hydrostatic pressure changes were studied We found that capillary fluid permeability in a tissue can be determined by the capill

Exposure assessment for the prevention of musculoskeletal disorders

Work-related musculoskeletal disorders of shoulder/neck are a major and increasing problem. Beside the pain, they involve high cost for the employer and society. The total expenditure for the musculoskeletal disorders of the neck and upper limb have been estimated to 0.5-2.0% of the Gross National Product (GNP) in the Nordic countries. Due to the lack of precise knowledge of exposure/response rela

Respiratory NAD(P)H dehydrogenases of plants - Gene identity and expression in response to light and cold

The respiratory chain of plants contains class 2 NAD(P)H dehydrogenases, not present in animals. The functional roles of these enzymes have been elusive for a long time. Two cDNAs, homologous to class 2 NADH dehydrogenase genes of yeast and E. coli, were isolated from potato leaves. The gene products, NDA1 and NDB1, were shown to reside on the internal and external sides of the inner mitochondrial

Energy Efficient Processes for the Production of Gaseous Biofuels - Reforming and Gas Upgrading

Replacing fossil fuels with biofuels is one way of reducing the emission of greenhouse gases into the atmosphere, thus decreasing our impact on the global climate. For this to be a viable option, several production routes are needed, as no single option can fully replace fossil fuels. One way of making biofuels more competitive with fossil fuels is by reducing the production cost. As most of the p

Laser Doppler Flowmetry and Imaging: Methodological Studies

Laser Doppler flowmetry (LDF) and laser Doppler imaging (LDI) are modern methods for non-invasive and continuous assessment of skin blood flow. The techniques are based on the phenomenon that monochromatic light transilluminating a perfused tissue is spectrally broadened owing to scattering by moving blood cells. In this study, methodological aspects of the two methods are presented. LDF was used

Cytogenetic studies of normal kidney tissue and renal cell carcinoma

In the present thesis normal kidney tissue and renal cell carcinoma (RCC) were studied by cytogenetic and fluorescence in situ hybridization (FISH) methods to investigate chromosomal aberrations. In the first study, 4 samples of nonneoplastic kidney tissue were cultured for cytogenetic analysis and trisomy 7 was found in all cases in 3-15% of the cells. In the second study, cytogenetic analysis o

Aspects of Optical Broad Band Spectroscopy and Information Extraction - Applications in Medicine and Ecology

The present thesis describes a number of aspects of modern electro-optical measurement technology also known as bio-photonics; this includes instrumentation, applications, sample interaction and data interpretation. The methods employed operate over several domains, and light measurements are discretized both in intensity, space, angle, time, polarization and energy. Mainly the spectral domain is

Waterfowl herbivory on submerged macrophytes in eutrophic lakes

Submerged macrophytes are thought to stabilize clear-water states of shallow lakes. The aim of this thesis was to elucidate how waterfowl herbivory can affect abundance, distribution and species composition of submerged macrophytes in eutrophic lakes. I found that in a lake with sparse vegetation, which was in a colonization phase, small plants were uprooted and large plants were heavily grazed up

Experimental Stroke and Neurotrophins: Regulation, function and gene transfer of neurotrophins in rat and mouse models of focal cerebral ischemia

Stroke caused by focal cerebral ischemia is a major cause of death and neurological disability in humans. The forebrain region most commonly affected by ischemic incidents is that supplied by the middle cerebral artery. In this thesis, neuronal cell death has been investigated using immunohistochemistry for identification of specific neurons and unbiased counting methods after transient occlusion

Perspectives of anxiety in stressful environments : Prospective studies in real-life settings

The present thesis deals with perspectives of anxiety experienced in stressful environments. As such two major issues are addressed. The first issue is whether increased trait anxiety during work in a high-stress environment is related to impaired performance on executive control tasks. The second issue is whether the characteristic of a stressor and pre-stress individual differences in executive

Water-swelling tablets based on hydrophobically modified poly(acrylic acid) - Effects of amphiphiles on swelling and drug release

An important issue within the pharmaceutical world today is the increasing number of poorly soluble drugs. These often show a low bioavailability and a susceptibility to varying conditions in the intestine. Hydrophobically modified poly (acrylic acid) (HMPAA), commercially available as Pemulen TR2, has shown promising abilities to control the release of especially poorly soluble substances. In thi

Studies on chondrocyte integrins and mechanical signaling

Integrins are a family of cell surface receptors known to bind matrix proteins and to mediate signals such as mechanical signals between the cell and the surrounding matrix. We have studied integrins that are expressed by chondrocytes, with specific focus on the integrins that interact with the cartilage matrix protein collagen type II. It was found that chondrocytes isolated from articular cartil

Evolution of Vertebrate Eyes: a study on lens suspension and optical proterties

Many fishes have well-developed visual systems with color vision capabilities. The crystalline lens is the major refractive element in a fish eye since the cornea is optically inactive underwater. A typical fish eye has a large pupil and a lens of short focal length, features that increase light gathering ability. They lead also to short depth of focus, which makes the eye particularly susceptible

The ubiquity and type diversity of papillomaviruses in normal skin

Papillomaviruses are a diverse, epitheliotropic group of viruses. Some genotypes are the main cause of anogenital cancer in humans; others can induce skin lesions. In order to investigate the occurrence of subclinical skin infections with human papillomavirus (HPV), a pair of degenerate primers (FAP59/64) was designed. Moist cotton-tipped swabs were used as a gentle method of sample collection. Di

Modeling and simulation of electro-viscoelastic polymers

The electroactive polymer materials considered in this work react to electric stimuli by producing deformations. In some cases, the electrically induced deformations are moderate, while in other cases they can be very large and the specimen is stretched to more than twice its original length. The latter response is seen in so called dielectric elastomer actuators (DEA). The possibility of very lar

Development of Magnetomotive Ultrasound Imaging

The earlier abnormalities coupled with disease can be discovered in the body, the larger is the chance to survive the disease. Molecular imaging is a growing research field which aims to detect these abnormalities at a molecular level, when the chance of survival is still high. The main idea of molecular imaging is to use target specific contrast agents that accumulate at the diseased region at a