11 resultados para population studies

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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Coastal birds are an integral part of coastal ecosystems, which nowadays are subject to severe environmental pressures. Effective measures for the management and conservation of seabirds and their habitats call for insight into their population processes and the factors affecting their distribution and abundance. Central to national and international management and conservation measures is the availability of accurate data and information on bird populations, as well as on environmental trends and on measures taken to solve environmental problems. In this thesis I address different aspects of the occurrence, abundance, population trends and breeding success of waterbirds breeding on the Finnish coast of the Baltic Sea, and discuss the implications of the results for seabird monitoring, management and conservation. In addition, I assess the position and prospects of coastal bird monitoring data, in the processing and dissemination of biodiversity data and information in accordance with the Convention on Biological Diversity (CBD) and other national and international commitments. I show that important factors for seabird habitat selection are island area and elevation, water depth, shore openness, and the composition of island cover habitats. Habitat preferences are species-specific, with certain similarities within species groups. The occurrence of the colonial Arctic Tern (Sterna paradisaea) is partly affected by different habitat characteristics than its abundance. Using long-term bird monitoring data, I show that eutrophication and winter severity have reduced the populations of several Finnish seabird species. A major demographic factor through which environmental changes influence bird populations is breeding success. Breeding success can function as a more rapid indicator of sublethal environmental impacts than population trends, particularly for long-lived and slowbreeding species, and should therefore be included in coastal bird monitoring schemes. Among my target species, local breeding success can be shown to affect the populations of the Mallard (Anas platyrhynchos), the Eider (Somateria mollissima) and the Goosander (Mergus merganser) after a time lag corresponding to their species-specific recruitment age. For some of the target species, the number of individuals in late summer can be used as an easier and more cost-effective indicator of breeding success than brood counts. My results highlight that the interpretation and application of habitat and population studies require solid background knowledge of the ecology of the target species. In addition, the special characteristics of coastal birds, their habitats, and coastal bird monitoring data have to be considered in the assessment of their distribution and population trends. According to the results, the relationships between the occurrence, abundance and population trends of coastal birds and environmental factors can be quantitatively assessed using multivariate modelling and model selection. Spatial data sets widely available in Finland can be utilised in the calculation of several variables that are relevant to the habitat selection of Finnish coastal species. Concerning some habitat characteristics field work is still required, due to a lack of remotely sensed data or the low resolution of readily available data in relation to the fine scale of the habitat patches in the archipelago. While long-term data sets exist for water quality and weather, the lack of data concerning for instance the food resources of birds hampers more detailed studies of environmental effects on bird populations. Intensive studies of coastal bird species in different archipelago areas should be encouraged. The provision and free delivery of high-quality coastal data concerning bird populations and their habitats would greatly increase the capability of ecological modelling, as well as the management and conservation of coastal environments and communities. International initiatives that promote open spatial data infrastructures and sharing are therefore highly regarded. To function effectively, international information networks, such as the biodiversity Clearing House Mechanism (CHM) under the CBD, need to be rooted at regional and local levels. Attention should also be paid to the processing of data for higher levels of the information hierarchy, so that data are synthesized and developed into high-quality knowledge applicable to management and conservation.

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Mitochondria are present in all eukaryotic cells. They enable these cells utilize oxygen in the production of adenosine triphosphate in the oxidative phosphorylation system, the mitochondrial respiratory chain. The concept ‘mitochondrial disease’ conventionally refers to disorders of the respiratory chain that lead to oxidative phosphorylation defect. Mitochondrial disease in humans can present at any age, and practically in any organ system. Mitochondrial disease can be inherited in maternal, autosomal dominant, autosomal recessive, or X-chromosomal fashion. One of the most common molecular etiologies of mitochondrial disease in population is the m.3243A>G mutation in the MT-TL1 gene, encoding mitochondrial tRNALeu(UUR). Clinical evaluation of patients with m.3243A>G has revealed various typical clinical features, such as stroke-like episodes, diabetes mellitus and sensorineural hearing loss. The prevalence and clinical characteristics of mitochondrial disease in population are not well known. This thesis consists of a series of studies, in which the prevalence and characteristics of mitochondrial disease in the adult population of Southwestern Finland were assessed. Mitochondrial haplogroup Uk was associated with increased risk of occipital ischemic stroke among young women. Large-scale mitochondrial DNA deletions and mutations of the POLG1 gene were the most common molecular etiologies of progressive external ophthalmoplegia. Around 1% of diabetes mellitus emerging between the ages 18 – 45 years was associated with the m.3243A>G mutation. Moreover, among these young diabetic patients, mitochondrial haplogroup U was associated with maternal family history of diabetes. These studies demonstrate the usefulness of carefully planned molecular epidemiological investigations in the study of mitochondrial disorders.

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Tyypin 1 diabeteksen perinnöllinen alttius Suomessa - HLA-alueen ulkopuolisten alttiuslokusten IDDM2 ja IDDM9 rooli taudin periytymisessä HLA-alue, joka sijaitsee kromosomissa 6p21.3, vastaa noin puolesta perinnöllisestä alttiudesta sairastua tyypin 1 diabetekseen. Myös HLA-alueen ulkopuolisten lokusten on todettu liittyvän sairausalttiuteen. Näistä kolmen lokuksen on varmistettu olevan todellisia alttiuslokuksia ja lisäksi useiden muiden, vielä varmistamattomien lokusten, on todettu liittyvän sairausalttiuteen. Tässä tutkimuksessa 12:n HLA-alueen ulkopuolisen alttiuslokuksen kytkentä tyypin 1 diabetekseen tutkittiin käyttäen 107:aa suomalaista multiplex-perhettä. Jatkotutkimuksessa analysoitiin IDDM9-alueen kytkentä ja assosiaatio sairauteen laajennetuissa perhemateriaaleissa sekä IDDM2-alueen mahdollinen interaktio HLA-alueen kanssa sairauden muodostumisessa. Lisäksi suoritettiin IDDM2-alueen suojaavien haplotyyppien alatyypitys tarkoituksena tutkia eri haplotyyppien käyttökelpoisuutta sairastumisriskin tarkempaa ennustamista varten. Ensimmäisessä kytkentätutkimuksessa ei löytynyt koko genomin tasolla merkitsevää tai viitteellistä kytkentää tutkituista HLA-alueen ulkopuolisista lokuksista. Voimakkain havaittu nimellisen merkitsevyyden tavoittava kytkentä nähtiin IDDM9-alueen markkerilla D3S3576 (MLS=1.05). Tutkimuksessa ei kyetty varmistamaan tai sulkemaan pois aiempia kytkentähavaintoja tutkituilla lokuksilla, mutta IDDM9-alueen jatkotutkimuksessa havaittu voimakas kytkentä (MLS=3.4) ja merkitsevä assosiaatio (TDT p=0.0002) viittaa vahvasti siihen, että 3q21-alueella sijaitsee todellinen tyypin 1 diabeteksen alttiusgeeni, jolloin alueen kattava assosiaatiotutkimus olisi perusteltu jatkotoimenpide. Sairauteen altistava IDDM2-alueen MspI-2221 genotyyppi CC oli nimellisesti yleisempi matalan tai kohtalaisen HLA-sairastumisriskin diabeetikoilla, verrattuna korkean HLA-riskin potilaisiin (p=0.05). Myös genotyyppijakauman vertailu osoitti merkitsevää eroa ryhmien välillä (p=0.01). VNTR-haplotyyppitutkimus osoitti, että IIIA/IIIA-homotsygootin sairaudelta suojaava vaikutus on merkitsevästi voimakkaampi kuin muiden luokka III:n genotyypeillä. Nämä tulokset viittaavat IDDM2-HLA -vuorovaikutukseen sekä siihen että IDDM2-alueen haplotyyppien välillä esiintyy etiologista heterogeniaa. Tämän johdosta IDDM2-alueen haplotyyppien tarkempi määrittäminen voisi tehostaa tyypin 1 diabeteksen riskiarviointia.

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Although abundant in the number of individuals, the Atlantic salmon may be considered as a threatened species in many areas of its native distribution range. Human activities such as building of power plant dams, offshore overfishing, pollution, clearing of riverbeds for timber floating and badly designed stocking regimes have diminished the distribution of Atlantic salmon. As a result of this, many of the historical populations both in Europe and northern America have gone extinct or are severely depressed. In fact, only 1% of Atlantic salmon existing today are of natural origin, the rest being farmed salmon. All of this has lead to a vast amount of research and many restoration programmes aiming to bring Atlantic salmon back to rivers from where it has vanished. However, many of the restoration programmes conducted thus far have been unsuccessful due to inadequate scientific research or lack of its implementation, highlighting the fact that more research is needed to fully understand the biology of this complex species. The White and Barents Seas in northwest Russia are among the last regions in Europe where Atlantic salmon populations are still stable, thus forming an important source of biodiversity for the entire European region. Salmon stocks from this area are also of immense economic and social importance for the local people in the form of fishing tourism. The main aim of this thesis was to elucidate the post-glacial history and population genetic structure of north European and particularly northwest Russian Atlantic salmon, both of which are aspects of great importance for the management and conservation of the species. Throughout the whole thesis, these populations were studied by utilizing microsatellites as the main molecular tool. One of the most important discoveries of the thesis was the division of Atlantic salmon from the White and Barents Seas into four separate clusters, which has not been observed in previous studies employing nuclear markers although is supported by mtDNA studies. Populations from the western Barents Sea clustered together with the northeast Atlantic populations into a clearly distinguishable group while populations from the White Sea and eastern Barents Sea were separated into three additional groups. This has important conservation implications as this thesis clearly indicates that conservation of populations from all of the observed clusters is warranted in order to conserve as much of the genetic diversity as possible in this area. The thesis also demonstrates how differences in population life histories within a species, migratory behaviour in this case, and in their phylogeographic origin affect the genetic characteristics of populations, namely diversity and divergence levels. The anadromous populations from the Atlantic Ocean, White Sea and Barents Sea possessed higher levels of genetic diversity than the anadromous populations form the Baltic Sea basin. Among the non-anadromous populations the result was the opposite: the Baltic freshwater populations were more variable. This emphasises the importance of taking the life history of a population into consideration when developing conservation strategies: due to the limited possibilities for new genetic diversity to be generated via gene flow, it is expected that freshwater Atlantic salmon populations would be more vulnerable to extinction following a population crash and thus deserve a high conservation status. In the last chapter of this thesis immune relevant marker loci were developed and screened for signatures of natural selection along with loci linked to genes with other functions or no function at all. Also, a novel landscape genomics method, which combines environmental information with molecular data, was employed to investigate whether immune relevant markers displayed significant correlations to various environmental variables more frequently than other loci. Indications of stronger selection pressure among immune-relevant loci compared to non-immune relevant EST-linked loci was found but further studies are needed to evaluate whether it is a common phenomenon in Atlantic salmon.

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Aims: This study was carried out to investigate the role of common liver function tests, and the degree of common bile duct dilatation in the differential diagnosis of extrahepatic cholestasis, as well as the occurrence, diagnosis and treatment of iatrogenic bile duct injuries. In bile duct injuries, special attention was paid to gender and severity distribution and long-term results. Patients and methods: All consecutive patients with diagnosed common bile duct stones or malignant strictures in ERCP between August 2000 and November 2003. Common liver function tests were measured in the morning before ERCP on all of these 212 patients, and their common bile duct diameter was measured from ERCP films. Between January 1995 and April 2002, 3736 laparoscopic cholecystectomies were performed and a total of 32 bile duct injuries were diagnosed. All pre-, per-, and postoperative data were collected retrospectively; and the patients were also interviewed by phone. Results: Plasma bilirubin proved to be the best discriminator between CBD stones and malignant strictures (p≤0.001 compared to other liver function tests and degree of common bile duct dilatation). The same effect was seen in Receiver Operating Characteristics curves (AUC 0.867). With a plasma bilirubin cut-off value of 145 μmol/l, four out of five patients could be classified correctly. The degree of common bile duct dilatation proved to be worthless in differential diagnostics. After laparoscopic cholecystectomy the total risk for bile duct injury was 0.86%, including cystic duct leaks. 86% of severe injuries and 88% of injuries requiring operative treatment were diagnosed in females. All the cystic duct leakages and 87% of the strictures were treated endoscopically. Good long-term results were seen in 84% of the whole study population. Conclusions: Plasma bilirubin is the most effective liver function test in differential diagnosis between CBD stones and malignant strictures. The only value of common bile duct dilatation is its ability to verify the presence of extrahepatic cholestasis. Female gender was associated with higher number of iatrogenic bile duct injuries, and in particular, most of the major complications occur in females. Most of the cystic duct leaks and common bile duct strictures can be treated endoscopically. The long-term results in our institution are at an internationally acceptable level.

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In general, models of ecological systems can be broadly categorized as ’top-down’ or ’bottom-up’ models, based on the hierarchical level that the model processes are formulated on. The structure of a top-down, also known as phenomenological, population model can be interpreted in terms of population characteristics, but it typically lacks an interpretation on a more basic level. In contrast, bottom-up, also known as mechanistic, population models are derived from assumptions and processes on a more basic level, which allows interpretation of the model parameters in terms of individual behavior. Both approaches, phenomenological and mechanistic modelling, can have their advantages and disadvantages in different situations. However, mechanistically derived models might be better at capturing the properties of the system at hand, and thus give more accurate predictions. In particular, when models are used for evolutionary studies, mechanistic models are more appropriate, since natural selection takes place on the individual level, and in mechanistic models the direct connection between model parameters and individual properties has already been established. The purpose of this thesis is twofold. Firstly, a systematical way to derive mechanistic discrete-time population models is presented. The derivation is based on combining explicitly modelled, continuous processes on the individual level within a reproductive period with a discrete-time maturation process between reproductive periods. Secondly, as an example of how evolutionary studies can be carried out in mechanistic models, the evolution of the timing of reproduction is investigated. Thus, these two lines of research, derivation of mechanistic population models and evolutionary studies, are complementary to each other.

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This work presents models and methods that have been used in producing forecasts of population growth. The work is intended to emphasize the reliability bounds of the model forecasts. Leslie model and various versions of logistic population models are presented. References to literature and several studies are given. A lot of relevant methodology has been developed in biological sciences. The Leslie modelling approach involves the use of current trends in mortality,fertility, migration and emigration. The model treats population divided in age groups and the model is given as a recursive system. Other group of models is based on straightforward extrapolation of census data. Trajectories of simple exponential growth function and logistic models are used to produce the forecast. The work presents the basics of Leslie type modelling and the logistic models, including multi- parameter logistic functions. The latter model is also analysed from model reliability point of view. Bayesian approach and MCMC method are used to create error bounds of the model predictions.

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Modern cancer therapy has resulted in increased survival among patients diagnosed with cancer at a young age. These improvements have led to the investigation of late morbidity and mortality associated with cancer and its treatments. The aim of this study was to evaluate late effects of cancer treated at a young age on the health of patients and their offspring. Utilising the nationwide population-based registries in Finland, we evaluated the risk of hypothyroidism and the probability of parenthood in cancer survivors as well as preterm birth, neonatal outcomes, and the risk of cancer among offspring of patients. The survivor cohort, identified from the Finnish Cancer Registry, consisted of 25,784 cancer patients diag-nosed between ages 0 and 34 in 1953–2004. By linkage to the population register, siblings of these patients were identified for comparison. The prevalence of hypothyroidism was higher among former childhood cancer (aged 0–16) patients than in the general population. The probability of parenthood following early onset cancer was overall significantly reduced compared to siblings. Offspring of female cancer survivors were at an increased risk of preterm birth, this risk being highest among patients diagnosed in childhood and early adulthood (aged 20–34 years). The offspring were not, however, at a significantly increased risk of neonatal death or stillbirth, though they were more likely to need monitoring or intensive care in the neonatal period. The risk of sporadic cancer among offspring of male and female cancer survivors was not elevated in comparison to the general population. The study showed that former cancer patients are at risk of certain adverse endocrine and reproductive health outcomes and should be followed for timely intervention. The offspring of cancer survivors do not appear to be at risk for adverse health outcomes.

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Aino Toiviainen Probiotics and oral health: in vitro and clinical studies University of Turku, Faculty of Medicine, Institute of Dentistry, Periodontology, Finnish Doctoral Program in Oral Sciences (FINDOS-Turku), Turku, Finland Annales Universitatis Turkuensis, Sarja – Ser. D, Medica-Odontologica. Painosalama Oy, Turku, Finland, 2015 Probiotics are used, for example, to prevent and treat diarrhea, allergies and respiratory infections, and there is an increasing interest to use probiotics also for oral health purposes. The most commonly used probiotic bacteria are lactobacilli and bifidobacteria, which are acidogenic and aciduric. From the oral point of view, use of these probiotics may, at least in theory, mean an increased risk of caries. In this thesis, the effects of probiotics on oral microbial composition, acid production of dental plaque and gingival health were studied through in vitro studies and two clinical studies. In a randomized, double-blind and crossover study, 13 healthy adults were allocated into two groups. Half of the subjects first consumed Lactobacillus rhamnosus GG tablets twice a day for two weeks, and after the washout period, L. reuteri tablets twice a day for two weeks. The other half of the subjects used the tablets in reverse order. In another controlled, randomized and double-blind study, 62 healthy adults were allocated into two groups. One group used the test tablets containing L. rhamnosus GG and B. lactis BB-12 and the other group used control tablets without probiotics. The recommendation for the use of the tablets was 4 per day for 4 weeks. Probiotic lactobacilli interfered with S. mutans biofilm formation and the adhesion of S. mutans to saliva-coated hydroxyapatite in vitro. No effect was found in S. mutans levels in the three-species biofilms. In clinical studies, the studied probiotics had no effect on the acid production of plaque. The counts of mutans streptococci and the oral microbial composition remained the same. Tablets containing L. rhamnosus GG and Bifidobacterium animalis subsp. lactis BB-12 did decrease the amount of plaque and gingival bleeding. According to our results, it seems that probiotics have beneficial effects on gingival health. The present results confirmed that probiotics are safe and have beneficial effects on oral health. Since the consumption of probiotics by the general population is steadily increasing, an understanding of the functions of probiotics in the oral cavity has become more important. Keywords: lactobacilli, bifidobacteria, caries, periodontal disease, mutans streptococci, probiotics

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The inability to achieve and to maintain erection, erectile dysfunction, is a bothersome symptom of elderly men. Moreover, there is a high comorbidity between cardiovascular diseases and erectile dysfunction. However, very little is known concerning the risk factors of ED in apparently healthy men without comorbidities affecting the arteries. A cross-sectional population survey was conducted from August 2005 to September 2007 in two rural towns of Harjavalta and Kokemäki in Finland. Excluding those with previously diagnosed cardiovascular diseases, diabetes or chronic kidney disease, every community-dwelling inhabitant was invited to take part in the survey. Of the 2939 45- to 70-year-old men invited, 2049 responded. Selecting those at risk for cardiovascular diseases, 1000 eligible men were examined. According to the International Index of Erectile Function short form 57% of the studied men reported erectile dysfunction. Increasing age, smoking, depressive symptoms, decreasing pulmonary function, sedentary lifestyle, non-marital status and low education level were associated with increasing risk of erectile dysfunction. However, hypertension, diabetes, obesity, hypercholesterolemia were not associated with erectile dysfunction, although these associations have been described in numerous previous studies. Moreover, erectile dysfunction was not associated with increasing risk of pre-diabetes. In apparently healthy men, increasing age, smoking, depressive symptoms, decreasing pulmonary function, sedentary lifestyle, non-marital status, low education level but not hypertension, obesity, hypercholesterolemia, diabetes or pre-diabetes were associated with increasing risk of erectile dysfunction.