Best macular dystrophy (BMD) is an autosomal dominant inherited eye disease with a juvenile onset. Accumulation of the pigment lipofuscin in the retinal pigment epithelium can later cause macular degeneration and loss of vision. BMD have histopathologic similarities with age-related macular degeneration, the most common cause of blindness among elderly. BMD diagnosis is made with fundus examination and electrophysiology. The VMD2 gene, causing BMD, has previously been localized to 11q13 using linkage and recombination of a 12 generation family with BMD. In this study the genetic region has been further narrowed using polymorphic markers in the BMD family. A human homolog for a C. elegans protein family, expressed in retina, was identified as the VMD2 gene. It has a 1755 bp open reading frame with 11 exons and encodes a 585 amino acid protein called bestrophin. Mutation analysis of the VMD2 gene in BMD families from Sweden, Denmark and Netherlands revealed 15 missense mutations, altering single amino acids in bestrophin, accumulating in the N-terminal half of the protein. VMD2 expression analysis with in situ hybridization revealed specific localization in the retinal pigment epithelium and Northern blot showed expression in retina and brain. Clinical and genetic analysis of a BMD family with generally late onset revealed a novel bestrophin mutation. Analysis of mouse Vmd2 and bestrophin during development showed presence of mouse bestrophin in retinal pigment epithelium at postnatal day 10 and in photoreceptor outer segments during the entire postnatal period. Vmd2 expression levels were highest around birth.

<b>Pressemelding:</b> Behandling av type 2 diabetes har trolig best effekt i en tidlig fase av sykdommen. Dette skriver assistentlege Elisabeth Qvigstad (36) fra Grimstad i doktoravhandlingen sin ved Norges teknisk-naturvitenskapelige universitet NTNU. Arbeidet kan bidra til at det utvikles nye medisiner mot diabetes. Avhandlingen tar utgangspunkt i type 2 diabetes, som rammer 105-120 000 nordmenn. Tidligere forskning i form av celle- og dyreforsøk har vist at vedvarende høye nivåer av fettsyrer i blodet og langvarig stimulering av insulinfrigjøring kan svekke funksjonen til de insulinproduserende beta-cellene i bukspyttkjertelen. Avhandlingen ville teste om lignende forhold er til stede hos mennesker og om korrigerende tiltak ville bedre insulinfrigjøringen ved type 2 diabetes. Nivået av frie fettsyrer hos personer med type 2 diabetes er oftest forhøyet. Langvarig faste hos friske gir også forhøyet fettsyrenivå og kan ses på som en modellsituasjon for type 2 diabetes. Qvigstad fant redusert insulinfrigjøring hos friske forsøkspersoner etter 58 timer faste. Fettsyrenivået i blod under testing ble senket ved hjelp av et nikotinsyrederivat hos friske personer og personer med type 2 diabetes. Hos friske påvirket ikke medikamentet insulinfrigjøring eller -følsomhet. Imidlertid virket behandlingen positivt på insulinfrigjøring hos de diabetikerne som hadde best blodsukker-kontroll. Derimot, når type 2 diabetikere reduserte fett i kosten, ga dette ingen utslag på insulinfrigjøringen, men noe nedsatt insulinfølsomhet. Nivået av fettvevshormoner (leptin, adiponectin) ble redusert. Den egne insulinfrigjøringen ble hemmet med medikamentet diazoxid, og insulininjeksjoner ble brukt som erstatning. Insulinfrigjøringen økte uten å endre insulinbehov eller blodsukkerkontroll sammenliknet med placebo. Disse resultatene tyder på at "betacelle-hvile" er gunstig ved type-2 diabetes. Qvigstads doktorgradsarbeid bidrar til økt forståelse av betydningen av fettsyrer for insulinfrigjøring og insulinfølsomhet hos friske og ved type 2 diabetes. I tillegg støtter funnene betydningen av "betacelle-hvile», som kan bidra til utvikling av nye medisiner mot diabetes. http://www.ntnu.no/doktorgrader/dr.med/02.03/qvigstad.htm

Diabetic nephropathy (DN) is associated with morbidity and mortality due to cardiovascular disease and renal failure. This study focused on the impact of glycemic control on the development of DN and the metabolic consequences of DN. The euglycemic hyperinsulinemic clamp technique was used to assess insulin sensitivity and insulin clearance. Two different registries, the Diabetes Incidence Study in Sweden (DISS) and the Swedish Childhood Diabetes Registry, as well as questionnaires and data from medical records were used to study diabetic complications in population-based cohorts. Microalbuminuria is an early marker of DN and may also be associated with impaired insulin sensitiv-ity in diabetic and non-diabetic subjects. We studied the relationship between insulin sensitivity and the degree of albuminuria in patients with type 1 diabetes and micro- or macroalbuminuria but normal glomerular filtration rate (GFR). We did not find a direct quantitative association between the degree of albuminuria and insulin resistance, arguing against a cause-effect relationship. With progression of DN, a decline in GFR is seen. Patients with severe renal failure have both im-paired insulin sensitivity and insulin clearance. We studied insulin sensitivity and insulin clearance in type 1 diabetes patients with three different degrees of renal involvement (none, only albuminuria, and slightly reduced GFR, ~40-70 ml/min/1.73 m2, respectively). A clear reduction in insulin sensitivity in vivo, but not in insulin clearance, was seen in the group with reduced GFR, and concomitant changes in the levels of PTH, IGF-1, IL-6 and TNF-α were found. In parallel, cellular insulin sensitivity and insulin degradation were examined in vitro, in subcutaneous fat cells but no differences were found between the three groups of patients. To study the occurrence of renal involvement in patients with modern diabetes treatment we moni-tored a cohort of young adults from the DISS-registry with onset of diabetes in 1987-88 at age 15-34 years. We found that ~7% of the patients had signs of renal involvement, i.e. incipient nephropathy (5%) and overt nephropathy (2%), after a median follow-up of ~9 years and the strongest risk markers were poor glycemic control (HbA1c) and high blood pressure. Patients with type 2 diabetes were most prone to have renal involvement in this age group. Retrospectively, we studied 94 patients diagnosed with type 1 diabetes in 1981-1992 at age 0-14 years at the Umeå University Hospital. Incipient nephropathy and background retinopathy occurred in 18 and 45%, respectively, of the patients, during ~12 years of follow-up. Glycemic control, also during the first five years of diabetes, was a strong risk marker. Young age at onset of diabetes prolonged the time to development of microvascular complications. Conclusion: Despite modern diabetes treatment some patients with diabetes develop renal involvement within the first ten years. Inadequate glycemic control, also early in the disease, is a risk marker as well as type 2 diabetes and high blood pressure. In patients with type 1 diabetes and diabetic neph-ropathy a slightly reduced GFR, but not albuminuria, is associated with insulin resistance. Concomi-tant changes in insulin-antagonistic hormones and cytokines may be involved.

The phylogeography of a wide ranging temperate species, the adder, Vipera berus, was investigated using several genetic tools, with special emphasis on the post-glacial colonisation pattern of Fennoscandia. The area was colonised from two directions by adder populations representing different glacial refugia. The two populations meet in three places and the main contact zone is situated in Northern Finland. The two other contact zones are the result of dispersal across the Baltic Sea to the Umeå archepelago and South-Western Finland. Asymmetrically distributed nuclear genetic variation compared to mitochondrial DNA in the northern contact zone suggests a skewed gene flow from the east to the west across the zone. This pattern might reflect differences in dispersal among sexes and lineages, or may be accounted for by a selective advantage for nuclear variation of eastern origin among Fennoscandian adders. The phylogeographic pattern for adders across the entire species range was addressed by sequencing part of the mitochondrial genome and scoring microsatellite markers. The adder can be divided into three major genetic groups. One group is confined to the Balkan peninsula harbouring the distribution range of V. b. bosniensis. A second, well differentiated group is restricted to the Southern Alps. These two areas have probably served as refugia for adders during a number of ice ages for the adders. The third group is distributed across the remainder of the species’ range, from extreme Western Europe to Pacific Russia and can be further divided into one ancestral group inhabiting the Carpathians refugial area, and three more recent groups inhabiting areas west, north and east of the Alps. The adder provides an example of a species where the Mediterranean areas are housing endemic populations, rather than the sources for post-glacial continental colonisation. Continent-wide colonisation has instead occurred from up to three cryptic northern refugia.

The studies in the present thesis sought to define virus and host factors that can influence on the susceptibility to murine retrovirus infection. In addition, we wanted to study possible correlations between events of early infection and subsequent disease progression. For an extensive discussion of the major findings, the reader is referred to papers I-IV. The following section will give a general discussion concerning 1) some methodological aspects; 2) the course of FIS-2 infection; 3) determinants responsible for erythroleukaemia; 4) determinants responsible for immunosuppression; and, 5) does sex matter?

The purpose of the study was to: • Study the effect of vascular gas bubbles on the brain and lung • Study changes in the endothelial function caused by gas bubbles • Study the preventive effects of monoclonal anti-C5a antibody on functional changes caused by gas bubbles It is important to reveal any changes in the function of the endothelium caused by gas bubbles, as the endothelium probably plays an important role in the development of decompression sickness (DCS). Furthermore, we followed up previous studies using monoclonal anti-C5a antibody trying to prevent damages caused by gas bubbles. In order to prevent damages causes by gas bubbles and maybe prevent DCS, the mechanisms behind have to be revealed. This thesis is part of an ongoing project that for several years has tried to bring to light the “secrets” of DCS.

Mitochondrial DNA (mtDNA) has been a potent tool in studies of the evolution of modern humans, human migrations and the dynamics of human populations over time. The popularity of this cytoplasmic genome has largely been due to its clonal inheritance (in Man) allowing the tracing of a direct genetic line. In addition, a comparatively high rate of nucleotide substitution facilitates phylogenetic resolution among relatively closely related individuals of the same species. In this thesis, a statistically supported phylogeny based on complete mitochondrial genome sequences is presented which, for the first time, unambiguously places the root of modern human mitochondrial lineages in Africa in the last 200 thousand years. This conclusion provides strong support for the “recent African origin” hypothesis. Also, the complete genome data underline the problematic nature of traditional approaches to analyses of mitochondrial phylogenies. The dispersal of anatomically modern humans from the African continent is examined through single nucleotide polymorphism (SNP) and sequence data. These data imply an expansion from Africa about 57 thousand years ago and a subsequent population dispersal into Asia. The dispersal coincides with a major population division that may be the result of multiple migratory routes to East Asia. Also investigated is the question of a common origin for the indigenous peoples of Australia and New Guinea. Previous studies have been equivocal on this question with some presenting evidence for a common genetic origin and other proposing separate histories. Our data reveals an ancient genetic link between Australian Aborigines and the peoples of the New Guinea highlands.

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The main purpose of the present work was to evaluate the efforts taken by the Norwegian surgical community in order to promote and enhance the standards of rectal cancer treatment on a national level, in particular: - to examine the outcome of rectal cancer surgery following implementation of total mesorectal excision as the standard rectal resection technique - to explore the prognostic impact of the circumferential resection margin on local recurrence, distant metastases and overall survival following mesorectal excision - to evaluate the oncological outcomes following mesorectal excision of cancer of the lower rectum, particularly the rates of local recurrence and overall survival for patients with tumours in this areas - to illustrate the influence of a rectal cancer registry as a quality control instrument on outcome of rectal treatment, and furthermore, to investigate the rates of postoperative mortality, anastomic leakage, local recurrence (LR) and overall survival related to hospital caseload among Norwegian hospitals during implementation of mesorectal excision.

The aim of this thesis is to study phylogeny, species-wide phylogeography and genetic diversity in Formica ants across Eurasia in connection with the history of biotic responses to Quaternary environmental changes. The mitochondrial DNA phylogeny of Palaearctic Formica species supported the subgeneric grouping based on morphological similarity. The exception was that F. uralensis formed a separate phylogenetic group. The mitochondrial DNA phylogeny of the F. rufa group showed the division into three major phylogenetic groups: one with the species F. polyctena and F. rufa, one with F. aquilonia, F. lugubris and F. paralugubris, and the third one with F. pratensis. West-east phylogeographic divisions were found in F. pratensis suggesting post-glacial colonization of western Europe and a wide area from Sweden to the Baikal Lake from separate forest refugia. In contrast, no phylogeographic divisions were detected in either F. lugubris or F. exsecta. Contraction of the distribution range to a single refugial area during the late Pleistocene and the following population expansion could offer a general explanation for the lack of phylogeographic structure across most of Eurasia in these species. Sympatrically distributed and ecologically similar species F. uralensis and F. candida showed clear difference in the phylogeographic structure that reflected difference in their vicariant history. Whereas no phylogeographic divisions were detected in F. uralensis across Europe, F. candida showed a well-supported phylogeographic division between the western, the central and the southern group. In socially polymorphic F. cinerea, the overall level of intrapopulation microsatellite diversity was relatively high and differentiation among populations was low, indicating recent historical connections. The lack of correspondence between genetic affinities and geographic locations of studied populations did not provide any evidence for differentiating between alternative hypotheses concerning the directions and sources of postglacial colonization of Fennoscandia.