E-thesis

Recent Submissions

  • Puonti, Päivi (Helsingin yliopisto, 2017)
    This dissertation is a collection of three self-contained essays that analyse the effects of monetary and fiscal policy using novel time series econometric methods. The research questions become important both academically and for practical policy-making after the global financial crisis of the early 2000s. The main contribution of the dissertation is in applying recent time series econometric methods to highly topical policy questions. Structural vector autoregressive (SVAR) models are an important tool in the empirical analysis of monetary and fiscal policy. The difficulty with conventional SVARs is the identification of structural shocks of interest needed for meaningful impulse response analysis. In this thesis I opt for a fairly novel approach to identify economically interpretable shocks which are then used to assess the macroeconomic effects of various economic policies. The so-called statistical identification consists of exploiting the statistical properties of the error processes, such as non-normality, to identify the structural model. In the three research chapters statistical, data-based information is combined with information from other sources. The assessment of economic policy can then be based on impulse response functions that are both economically meaningful and compatible with the sample data. In Chapter 2 I study the macroeconomic effects of the risk taking channel of monetary policy. The methodological improvement makes previously used identifying restrictions statistically testable and confirms that the balance sheet management of financial intermediaries led to a lower price of risk and higher real activity in the US before the financial crisis. Chapter 3 addresses the question whether increasing government spending stimulates real activity in the US. Unlike previous empirical research using SVARs I estimate a vector error correction model (VEC) that takes into account cointegration between the variables and use non-normality of the error processes for identification. The results show that when the empirical literature does not seem to reach a conclusion – in this case with respect to the sign or size of the fiscal multiplier – the identification strategy could play a role. In Chapter 4 I analyse the macroeconomic effects of the Bank of Japan’s, the Federal Reserve’s and the European Central Bank’s unconventional monetary policies. The use of a novel Bayesian SVAR method allows basing the whole analysis on the data and provides a formal way to assess the plausibility of given sign restrictions against the data. The analysis reveals differences in the output and price effects of the three central banks’ balance sheet operations.
  • Kontro, Mika (Helsingin yliopisto, 2017)
    Direct translation of cancer-specific genomic information into effective personalized therapies for acute leukemias has proven to be difficult. The aim of this study was to utilize novel tools for detailed characterization of genomic, transcriptomic, and functional aberrations in acute leukemia to gain understanding of disease pathology and guide individualized therapies. The main methods used were ex vivo drug sensitivity and resistance testing (DSRT), exome and transcriptome (RNA) sequencing, all of which were facilitated by extensive biobanking. In study I, we developed DSRT platform performed on primary leukemic cells ex vivo for identification of effective patient-specific drugs. Exome and RNA sequencing of serial samples were used for molecular characterization and to understand mechanisms of acquired resistance. Although AML samples exhibited unique DSRT profiles, responses could be clustered in five distinctive groups. Individualized treatment of refractory patients with DSRT-guided therapy resulted in meaningful clinical responses in 3/7 patients. In study II, we studied molecular drivers for relapsed T-cell acute lymphoblastic leukemia (T-ALL) and found novel STAT5B mutations. Functional studies demonstrated these mutations to enhance the transcriptional activity and to induce constitutive phosphorylation of STAT5B. The mutated blasts showed elevated BCL-XL expression and sensitivity to the pan-BCL-2 inhibitor navitoclax. Targeted sequencing revealed activating STAT5B mutations in 6/68 patients. In study III, we first evaluated ex vivo BCL-2 inhibitor sensitivity of AML cells, then we systematically assessed whether these responses correlated to specific mutations or gene expression signatures. BCL-2 inhibitor sensitivity associated with mutations in IDH1/IDH2 and WT1, as well as with aberrations in chromatin modifiers. Importantly, overexpression of a specific set of HOX genes predicted highly selective responses to BCL-2 inhibition. In study IV, we developed a national hematological biobank to allow researchers to access high-quality samples with accompanying clinical data. The samples from three collection time-points—diagnosis, potential remission, and relapse—are available. For this study, we evaluated the quality of stored samples and demonstrated that extracted DNA and RNA remain usable for demanding down-stream experiments.
  • Möller, Tia (Suomalainen Lakimiesyhdistys, 2017)
    The Europeanization of private international law is a well-recognized fact. The European Union (EU) has adopted a number of legal instruments in the field of private international law (PIL) in order to create a European area of justice, the objective defined by the EU Treaties. In addition to the Treaty provisions and the EU legislature there is also a third element influencing the Europeanization of PIL: multiannual programmes for the Area of Freedom, Security and Justice. These multiannual programmes have been adopted successively since 1998 (Vienna Action Plan 1998, Tampere Conclusions 1999, Hague Programme 2004, Stockholm Programme 2009, Strategic Guidelines 2014), and they have been adopted by the European Council, and thus by the Member States together with the Commission, and since the Lisbon Treaty, with the president of the European Council. This study analyses the impact of the multiannual programmes in the EU legislative process in the field of PIL and thus, their impact for the Europeanization of PIL. This is discussed from the various angles: the programmes’ relationship to the relevant EU Treaty provisions, concrete guidelines in the programmes for PIL (thus defining the vision of EU PIL) and the programmes’ influence on the EU legislative process. The latter aspect is analysed by examining all the EU PIL legislative acts adopted thus far. Moreover, possible future changes to the content and adoption procedure of multiannual programmes and their impact on future Europeanization of PIL are discussed. The study proposes that the vision of a European area of justice created by the multiannual programmes has played a central role not only in defining the direction of the Europeanization of PIL but also in its actual Europeanization, i.e. in the adoption of EU PIL instruments. In particular, in the area of family law, which varies widely between different legal traditions and legal cultures, the vision of a European area of justice has fostered a common understanding of the legislative work required, thereby furthering the Europeanization of PIL. The multiannual programmes have determined, prior to the formal EU legislative procedure, the PIL issues to be addressed by various legislative acts and also defined the general principles on which PIL cooperation should be based in the EU. The vision has brought real value to the EU Treaty provisions. However, the impact has been limited due to the general nature of the programmes and their limited possibilities in influencing the law on its different aspects. The study is based on the paradigms of legal dogmatics, i.e. legal positivism and the theory of the sources of law. The study uses methods from law and politics and legal history. The impacts of the programmes for the Europeanization of PIL are reflected on different aspects of law: legal order, judicial practices, the legal system and legal culture.
  • Salo, Emma (Helsingin yliopisto, 2017)
    This thesis investigated brain activity with functional magnetic resonance imaging (fMRI) during selective and divided attention. Selective attention refers to the ability to selectively attend and process certain stimuli while ignoring others. Divided attention is needed, when two or more tasks requiring selective attention are performed in parallel. However, attention is easily caught by sudden changes in the environment. Brain activity and task performance during distracted and undistracted attention was also compared. The results showed that selective attention to auditory or visual modality enhanced activity in the auditory and visual cortices, respectively. However, the results also implied that the effects of selective attention may be influenced by task-irrelevant variation of the stimuli. The present thesis also showed that during divided attention, when two cognitively demanding tasks are performed in parallel, brain activity is enhanced in cortical areas in relation to the two tasks performed one at a time. Such activity enhancements specifically associated with divided attention were found in left middle frontal cortex during several different divided attention tasks. This suggests that division of attention requires specific, higher-level cognitive processes not needed in other attention-engaging tasks. However, not all dual tasks were associated with frontal activity enhancements. Complex selective attention tasks performed in parallel with another selective attention task may influence the higher-level cognitive processes or integration of two tasks needed during dual tasking.
  • Ren, Wei (Helsingin yliopisto, 2017)
    Nanowires (NWs) and nanotubes (NTs) are considered to be of great importance for future nanotechnology applications, due to the roles of dimensionality and small system size. Potential applications of NWs and NTs range from field-effect transistors to biological applications. However, the one-dimensional (1D) nanostructures and most of their applications are still in an early stage of technical development. There are several issues that need to be addressed before they are ripe for industrial applications. Irradiation has been widely used in semiconductor industry to modify the properties of materials since the 1950s. Irradiation in 1D nanomaterials has been studied to tailor the mechanical, electronic, optical and even magnetic properties in a controlled manner, to improve the functionality of the devices based on the 1D nanomaterials. This thesis focuses on the structural and mechanical modifications of the 1D nanomaterials under energetic ion irradiation, as well as the formation mechanisms of the composites of the functional one-dimensional nanomaterials to improve their usage. In the first part, we studied the defect production of GaN NWs under Ar irradiation. The difference of defect production between NWs and the bulk counterpart was studied. The effect of the large surface-area-to-volume ratio was found to play an importance role in defect production in NWs. The irradiation energy of the maximum damage production in the NWs has been obtained. In the second part of the thesis, we studied the formation of the composite nanomaterials of diamond-like-carbon (DLC) and carbon nanotubes (CNTs). We used the classical MD method to simulate the deposition process of carbon atoms on the CNT systems to provide the atomic insights into structural changes. The results show that high-sp$^3$-content DLC can be formed provided the deposition conditions allow for sidewards pressure to form from a substrate close beneath the CNTs.
  • Bukonte, Laura (Helsingin yliopisto, 2017)
    Defects always exists in a crystal lattice at temperatures above absolute zero. Our knowledge of defect concentration and mobility is crucial, due to their profound influence on the material properties. It has been shown that the presence of light impurities may enhance vacancy formation in many metals and metal alloys. The main reason for this phenomenon, often referred to as the superabundant vacancy formation, is the lowering of the vacancy formation energy due to the impurity trapping. In this thesis a theoretical thermodynamics model has been developed to study the equilibrium vacancy concentrations as a function of impurity concentration and temperature. The diffusion of monovacancies and hydrogen in tungsten is studied due to its relevance to fusion research. The molecular dynamics method has been used to simulate the diffusion of hydrogen and monovacancies in tungsten. The commonly accepted and so far used H diffusion migration barrier is revised and a new analysis method to determine diffusion coefficients that accounts for the random oscillation of atoms around the equilibrium position is presented. The results show the presence of multiple nearest neighbour jumps of monovacancy above 2/3 of the melting temperature of tungsten, that partly explains the upward curvature of Arrhenius diagram of self-diffusion experiments in tungsten. For the first time, the W monovacancy diffusion prefactor is calculated, and found to be unexpectedly high, resulting in a monovacancy diffusion attempt frequency of about 2-3 orders of magnitude higher than the values commonly used. A comparative study between the molecular dynamics and a Monte Carlo method – binary collision approximation has been carried out by simulating the single ion impacts on silicon and tungsten surfaces. The results from both methods are compared and found to be in a good agreement for crystalline structures. However, large discrepancies between the two methods arise for materials that are amorphous or become amorphized during ion irradiation.
  • Tenca, Andrea (Helsingin yliopisto, 2017)
    BACKGROUND AND AIM This thesis includes two studies conducted in a paediatric and two studies conducted in an adult primary sclerosing cholangitis (PSC) population. The common denominator was endoscopic retrograde cholangiography (ERC) with brush cytology that was performed in all patients. The aims were to: i) identify the possible environmental risk factors (Study I) and report the long-term outcome (Study II) of paediatric-onset PSC, ii) compare ERC and magnetic resonance imaging with cholangiopancreatography (MRI-MRCP) in the evaluation of disease activity and severity of patients with PSC (Study III) and evaluate the role of ERC with brush cytology as screening for cholangiocarcinoma (CC) in patients with PSC (Study IV). MATERIAL AND METHODS PSC was diagnosed, followed-up (or both) in Helsinki University Hospital (HUH). Study I: 71 patients with a new diagnosis of paediatric-onset (age < 16 years) PSC, autoimmune hepatitis (AIH) or PSC-AIH (togheter autoimmune liver diseases or AILD) between 1985-2011. Two control groups were used: 1) 91 IBD patients matched for gender and age, collected from the IBD Population Registry at HUH and 2) 716 healthy subjects matched for gender, age and also place of birth at the time of AILD diagnosis, collected from the Population Registry Centre. A questionnaire of 22 items was administered. Study II: 41 patients with a new diagnosis of paediatric-onset PSC between 1993-2011. Study III: 48 patients with PSC who underwent ERC and MRI-MRCP within + 3 months for the diagnosis or the follow-up of the disease. Study IV: 261 patients with a new diagnosis of PSC (age > 18 years) between 1 January 2006 and 31 October 2011. All cholangiographic images were scored according to the modified Amsterdam PSC score. RESULTS Study I: In multivariate analysis, children ‘living with a cat in a block of flats’ had a higher risk (OR 3.6; 95% CI: 1.2-10.8) of having AILD than healthy controls, but not IBD controls. Study II: At the end of follow-up (9 years, range 2-20 years) all children were alive and no malignancy occurred. 29/33 (88%) were not transplanted; 26/29 (78%) were not cirrhotic and 3/29 (10%) were cirrhotic. 4/33 (12%) were transplanted after a median of 7.5 years; no PSC recurrence in the graft occurred. Study III: MRCP and ERC scores for IHBD were associated with alkaline phosphatase (p = 0.016 and p = 0.018, respectively) and CA19-9 level (p < 0.001 and p = 0.030, respectively); MRCP score for EHBD was also associated with CA19-9 level (p = 0.021). Finally, peribiliary enhancement detected on MRI correlated with cytology findings for both IHBD (Spearman’s rho = 0.322, SE: 0.095, p = 0.022) and EHBD (Spearman’s rho = 0.319, SE: 0.113, p = 0.025, respectively). Study IV: Most of the patients were asymptomatic (211/261; 80.8%) and had only mild changes on cholangiography (149/261; 57.1%) at time of first ERC. Follow-up was completed in 249/261 (95%). CC developed in 7 patients and biliary dysplasia in 8 patients; brush cytology was suspicious or malignant in 8 patients at time of PSC diagnosis. Advanced EHBD cholangiographic changes (HR: 1.7; 95% CI: 1.2-2.3) and alanine aminotransferase (HR: 14.2; 95% CI: 1.9-106.4) were associated with increased risk of biliary neoplasia. CONCLUSIONS An unidentified environmental risk factor (i.e., microbial) especially associated with cats may increase the risk of PSC in children. The clinical course and outcome of paediatric-onset PSC seems to be good until adulthood with a high survival rate, with no occurrence of malignancy and LT required in only a minority of patients. MRI-MRCP use in PSC follow-up seems to be low. In this respect, ERC with brush cytology is a good screening tool for detection of biliary dysplasia or neoplasia (or both) in patients with PSC. Advanced extrahepatic disease and alanine aminotransferase elevation may predict the occurrence of CC.
  • Känsäkoski, Johanna (Helsingin yliopisto, 2017)
    Sexual differentiation and pubertal development are complex processes whose disruption leads to the abnormal development of primary and/or secondary sexual characteristics. Although mutations in several genes have been implicated in these disorders, the majority of the patients still lack a molecular genetic diagnosis. The aim of this thesis work was to identify genetic defects underlying complete androgen insensitivity syndrome (CAIS), congenital hypogonadotropic hypogonadism (CHH) and gonadotropin-dependent precocious puberty (GDPP), in Finnish and Danish patients. The genetic cause of CAIS was investigated in two siblings without identified mutations in the androgen receptor gene (AR). Whole-genome sequencing and AR cDNA analysis revealed a deep intronic mutation that led to abnormal splicing of AR mRNA and undetectable amount of AR protein in patient fibroblasts. The genetic causes of both extremes of pubertal variation, GDPP and CHH, were investigated in Danish patients. Twenty-nine Danish girls with GDPP were screened for mutations in MKRN3, which was recently identified as a regulator of pubertal onset, and one girl was found to have a mutation in this gene. Forty-one Danish CHH patients were screened for mutations in the CHH genes ANOS1, FGFR1, FGF8, PROK2, PROKR2, GNRHR, TAC3, TACR3, and KISS1R. Additionally, CHD7 was screened in two patients with hearing loss. Twelve patients were found to have a conclusive mutation; either in FGFR1 (5), ANOS1 (4), GNRHR (1), or CHD7 (2). SEMA3A and SEMA7A, two candidate genes of CHH, were screened in fifty Finnish CHH patients. Three SEMA3A variants and two SEMA7A variants were identified in the patients, but the identified variants do not seem to be sufficient to cause CHH alone. In conclusion, the intronic AR mutation is the first reported case of pseudoexon activation leading to CAIS demonstrating the importance of AR cDNA analysis in AIS patients without a molecular genetic diagnosis. Mutations in MKRN3 underlie GDPP in Denmark, although they are not very common in sporadic cases. FGFR1, ANOS1, GNRHR, and CHD7 mutations were found to underlie CHH in the Danish patients, but the majority still remain without a molecular genetic diagnosis. Finally, mutations in SEMA3A and SEMA7A do not seem to contribute significantly to CHH, and it remains to be seen whether mutations in these genes cause CHH in humans.
  • Tuori, Klaus (2017)
    The thesis assesses the constitutional implications of the Eurosystem’s changing role and measures during the crisis. It is a supranational central banking system that does not have the state’s economic and political will-formation as its counterpart and control, but rather the constitutional framework in which it was supposed to work, called the European economic constitution. The common macroeconomic policy was elevated to a constitutional level in the Maastricht Treaty and the underlying economic, political and even constitutional assumptions and constraints were agreed upon. The Eurosystem can be assessed as an economic policy actor. How it achieves its objectives and how it performs its tasks. As an independent EU expert institution it also needs to be assessed on the grounds of how it respects and advances the values it is supposed to protect and serve, which is a constitutional perspective. The main question is twofold: How should the legal mandate of the Eurosystem and the ECB be defined and how should the Eurosystem’s measures during the crisis be constitutionally assessed? In the first part, the thesis discovers the economic and institutional framework of the EMU, by reconstructing this economic framework as the European economic constitution. The new elements introduced in the Maastricht Treaty formed a new macroeconomic layer to it, named the European macroeconomic constitution. The EMU and the European macroeconomic constitution are based on three different foundations. The philosophical foundation was economic constitutional thinking largely based on the German ordoliberal approach to the economy. The economic foundation was built on the evolution in central banking and economics that culminated in some form of consensus towards the end of the 1980s. The institutional foundation was the economic, political and legal development in the EU that pave the way towards macroeconomic integration in the form of a common currency. These three different but interlinked foundations happened to share a common ground towards the end of the 1980s and early 1990s that made an agreement on the main elements of the Maastricht Treaty possible. The first part concludes with the forming of the key constitutional principles of the European macroeconomic constitution. The second part of the book places the principles to the test of reality, by analysing the common central banking system through the lens of the constitutional principles, including assessments of many unconventional and contested decisions and measures by the Eurosystem during the crisis. The final conclusions ask some simple questions that raise issues of the constitutional implications of the economic and constitutional crisis and particularly the Eurosystem’s responses to and during the crisis.
  • Mäkinen, Hanna (Helsingin yliopisto, 2017)
    Climate change is characterized by uncertainty in climate and increasing variability in weather. In addition to traditional ‘predict and adapt’ approaches of preparing for projected average long-term change in climate, approaches addressing adaptive capacity and system resilience are required. Diversity is associated with enhanced stability and resilience in the face of climate change. However, any kind of diversity does not necessarily enhance resilience, but the diversity of responses is critical to resilience. Such response diversity means that the ability to react to changes and variability differs within a functional group. In this thesis, response diversity was empirically assessed using forage crops, a response diversity index (RD-index) was constructed and the practical significance of the RD-index was demonstrated. Forage crops were chosen for the studies because they are a cornerstone of Finnish dairy and beef farming. The following species and their cultivars were included: timothy (Phleum pratense L.), meadow fescue (Festuca pratensis Huds.), tall fescue (Festuca arundinacea Schreb. syn. Lolium arundinaceum Schreb.), festulolium (Festulolium pabulare), Italian ryegrass (Lolium multiflorum L.) and red clover (Trifolium pratense L.). The analyses started with testing the effect of the hypothetically critical agro-climatic variables on forage crop yield performance using plant data from the Official Variety Trials of Natural Resources Institute Finland (126 cultivars) and the weather data of the Finnish Meteorological Institute from 1979 to 2012 that was matched to the phenology of the crops. A linear mixed model was used to determine the effect of the site, year and weather on crop yields (I, II). In the second round of analyses, the three-way interaction of cultivars, soil types and weather were analysed using mixed models (III). Within-species diversity of responses to individual weather variables was firstly investigated for the modern set of forage crop cultivars. The results revealed that in these, within-species diversity in response to weather was generally low, particularly within the modern set of timothy and meadow fescue cultivars. On the other hand, the set of modern festulolium cultivars showed higher levels of differences in responses, which indicates their greater capacity to cope with climate change (II). Principal component analysis was used to determine common weather patterns, and forage crops and their cultivars were clustered based on the scores of the principal component analysis (I, III). Response diversity to the critical weather patterns within the set of forage crop species and cultivars was found. The value of the RD-index, measured as numbers of identifiable functional groups of species and cultivars with similar yield responses, was 10 across the soil types. An increase in RD-index decreased the yield response variation. The practical significance of complementarity of yield 10 responses of forage crops and their cultivars represents an option for the enhancement of climate resilience of feed production. The RD-index of forage crops and their cultivars varied from one climate–soil type pattern to another, with the following RD-index values: coarse mineral soils = 4, clay = 9, organic soils = 8 (III). Due to the demonstrated dependency of crop responses to climate change on soil type, attention should be given to the plausible shifts in soil–climate combinations when planning adaptation.
  • Suomi, Irene (Helsingin yliopisto, 2017)
    Wind gusts, which are short duration (typically 3 s) wind speed maxima, are representative of the extreme wind conditions. They are very important for human activity, because the strongest gusts associated with storms are the most significant single cause of natural hazards. The impact of wind gusts on different structures depends on the characteristics of each structure. For example for wind energy, it is important to know both the probability of extreme maximum gusts in time scales of decades for the design of power plants and in the shorter term to support wind turbine operations. For wind gust forecasting it is essential to have reliable wind gust observations. Traditionally, observations have only been available from weather stations where the wind is usually measured at a reference height of 10 m. For wind energy, information is needed at greater heights, as the hub heights of the largest turbines extend even above 150 m. The main aim of this work has been to investigate wind gusts across the entire atmospheric boundary layer based on observations from tall meteorological masts as well as applying new measurement methods developed in this dissertation. The novel methods are based on turbulence measurements taken on board a research aircraft and by a Doppler lidar. The research aircraft can fly long distances in a short time, so the measured wind speeds do not represent wind speed variation in time but they are a function of flight distance. The new method developed in this dissertation to compare temporal and spatial scales allows the measurement of wind gusts from a research aircraft. Then, observations can be obtained from places where traditional weather stations or meteorological masts cannot be deployed. Applying the new method, the observed wind gusts from the marine Arctic matched well with those observed at a meteorological mast in the Baltic Sea, although also differences were observed between these environments. Doppler lidar provides radial wind speed measurements along a laser beam transmitted by the instrument. When data from at least three lines of sight are combined, the three-dimensional wind vector can be derived. However, the measurements from multiple lines of sight take several seconds, and the different beams represent different measurement volumes. For these reasons, the measured wind speed maxima from the Doppler lidar used in this work were higher than the corresponding wind gusts from the nearby meteorological mast. In this dissertation, we developed a new theoretical method that significantly reduced this positive bias. Wind gust measurements are usually prone to measurement errors, called outliers. The use of a spike removal algorithm typically applied in traditional turbulence measurements, resulted in significantly improved Doppler lidar data quality. The method performed even better than the traditional data quality assurance methods based on carrier-to-noise ratio, by removing the unrealistic outliers present in the time series. Based on the above wind gust measurements, it was found that in the lowest part of the atmospheric boundary layer the ratio of the wind gust speed and the mean wind speed, called the gust factor, decreases strongly with measurement height. The higher the aerodynamic roughness of the surface, the greater is the change. Moreover, the static stability of the atmosphere affects the gust factor: the decrease of the gust factor with height is clearly smaller in unstable than in stable conditions. The gust parameterizations used in numerical weather prediction models were originally designed for the reference measurement height of 10 m. A new parameterization was developed that takes into account not only the effects of surface roughness and atmospheric stability but also the height above the surface. Based on meteorological mast and research aircraft measurements, the new parametrization yielded better results than previous methods.
  • Laakko, Maria (2017)
    Gene therapy is the therapeutic delivery of nucleic acid sequences into cells, where they can replace a gene that is missing, mutated or poorly expressed. It is a potential treatment to cure e.g. genetic diseases, viral infections and various cancers. The nucleic acid needs to be delivered across the cell membrane and into the nucleus to affect the gene expression. Anionic nucleic acids need a cationic carrier, such as a cationic liposome, to enable their delivery into the cells. The liposomes used in gene delivery usually contain both a cationic lipid to associate with the nucleic acid and a neutral helper lipid to stabilize the structure. The liposome-nucleic acid complex is called a lipoplex. The cationic carrier must include or function as a cell-penetrating enhancer (CPE) to be able to translocate across the cell membrane into the cytosol and to the nucleus. The experimental part of this work was aimed at developing and characterizing an innovative poly-cationic liposomal platform for gene delivery, using a novel synthetic CPE. The CPE used in this study is an oligo-guanidyl derivative (OGD) that had either 4 (OGD4) or 6 (OGD6) cationic charges. Liposomes were surface-engineered with OGD, obtaining a cationic formulation that was then exploited for DNA loading. The study has two main characterization steps: Step 1 was to decorate liposomes with OGD by post insertion using increasing amounts of OGD, and determine the vesicle size and zeta potential by dynamic light scattering (DLS). Step 2 involved DNA loading by post insertion into the cationic liposomes with increasing amounts of DNA. The lipoplex size and zeta potential was determined by DLS, the complexation by electrophoresis, and the thermodynamics of the cationic liposome/DNA association by isothermal titration calorimetry (ITC). The measurements were performed in isotonic buffers (HEPES pH 7.4 and citrate pH 5) and in lower ionic strength TRIS buffer (pH 7.4). The aim of the characterization studies was first to find a liposome composition that includes just enough OGD to obtain a sufficiently high zeta potential and a uniform, sufficiently small size. The optimal formulation contained either 10 % of OGD4 or 5 % of OGD6 of the total lipid amount. The second step was to find the highest stable DNA loading for the lipoplexes. All the characterization studies were performed on OGD4 lipoplexes in TRIS buffer. The optimal OGD4/DNA N/P (nitrogenous/phosphorous) ratio was found to be around 5. Further investigation is needed to determine the best lipoplex composition and manufacturing method using an isotonic buffer. A DNA release study remains to be performed prior to further in vitro and in vivo studies.
  • Konttinen, Riikka (2017)
    C-hepatiitti on veren välityksellä tarttuva virussairaus. Krooninen C-hepatiitti aiheuttaa maksavaurioita, kuten maksafibroosia, maksakirroosia ja maksasyöpää. Suomessa arvioidaan olevan 20 000 - 30 000 C-hepatiittiviruksen kantajaa. Aiemmin C-hepatiitin standardihoito on perustunut pegyloidun interferonin ja ribaviriinin yhdistelmähoitoon. Standardihoidolla ei ole saavutettu riittävää hoitovastetta ja hoidosta on aiheutunut potilaille haittavaikutuksia. Vuodesta 2014 lähtien markkinoille on tullut uusia tehokkaita viruksen rakenneproteiineja ja entsyymejä vastaan tarkoitettuja virusspesifisiä lääkkeitä C-hepatiitin hoitoon. Toisen polven virusspesifiset lääkkeet ovat tehokkaita, turvallisia ja hyvin siedettyjä. Niiden ainoa haitta on korkea hinta, jonka vuoksi lääkkeiden käyttöä on jouduttu rajoittamaan ainoastaan vakavasta maksavauriosta kärsiville potilaille. Terveydenhuollossa käytettävissä olevat varat ovat rajalliset, joten tietoa toisen polven virusspesifisten lääkkeiden kustannusvaikuttavuudesta tarvitaan päätöksenteon tueksi. Tämän pro gradu-tutkielman teoriaosuudessa kuvataan C-hepatiitin hoito ja hoitokäytännöt Suomessa sekä C-hepatiitista aiheutuvia kustannuksia. Lisäksi kuvataan taloudellisen arvioinnin ja järjestelmällisen kirjallisuuskatsauksen menetelmät ja käsitteet. Tutkielman tavoitteena on järjestelmällisen kirjallisuuskatsauksen avulla arvioida C-hepatiitin hoidossa käytettävien toisen polven virusspesifisten lääkkeiden kustannusvaikuttavuutta standardihoitoon verrattuna. Lisäksi arvioidaan järjestelmälliseen kirjallisuuskatsaukseen sisällytettyjen tutkimusten laatu. Tutkielman aineistona käytettiin aikaisemmin julkaistuja tutkimuksia, joissa on arvioitu toisen polven virusspesifisten lääkkeiden kustannusvaikuttavuutta. Kirjallisuushaun perusteella löytyi yhteensä 435 viitettä. Lisäksi järjestelmälliseen kirjallisuuskatsaukseen sisällytettyjen artikkelien viiteluettelosta löytyi kaksi mukaanottokriteerit täyttävää artikkelia. Järjestelmälliseen kirjallisuuskatsaukseen valittiin lopulta 25 alkuperäistutkimusta ja yksi aiemmin julkaistu järjestelmällinen kirjallisuuskatsaus. Tutkimuksista kerättiin ja taulukoitiin keskeiset tiedot. Tutkimusten laatua arvioitiin kolmella eri laadunarviointiin käytettävällä tarkistuslistalla. Toisen polven virusspesifisten lääkkeiden kustannusvaikuttavuudesta ei voitu tehdä johtopäätöksiä aikaisempien tutkimusten perusteella, koska kirjallisuushaun perusteella löytyi vain yksi aiemmin julkaistu järjestelmällinen kirjallisuuskatsaus. Tutkielman perusteella toisen polven virusspesifisten lääkkeiden inkrementaalinen kustannusvaikuttavuussuhde (ICER) vaihteli dominanssin ja 1 135 655 € /QALY:n välillä verrattuna standardihoitoon. Kun toisen polven virusspesifistä lääkettä verrattiin vaihtoehtoiseen toisen polven virusspesifiseen lääkkeeseen, ICER vaihteli dominanssin ja 65 281 € /QALY:n välillä. Kun arvioitiin maksavaurion vaikutusta toisen polven virusspesifisten lääkkeiden kustannusvaikuttavuuteen, havaittiin että kirroottisilla potilailla toisen polven virusspesifisten lääkkeiden ICER vaihteli 299 € - 85 195 € /QALY:n välillä. Ei-kirroottisilla potilailla ICER vaihteli 2182 € - 177 679 € /QALY:n välillä. Kun arvioitiin aineiston pohjalta tutkimusten rahoittajan yhteyttä kustannusvaikuttavuuteen, havaittiin että tutkimuksen rahoittajan ollessa lääkeyhtiö, ICER vaihteli 1717 € - 86 056 € /QALY:n välillä. Muun tahon rahoittamissa tutkimuksissa ICER vaihteli 299 € - 1 135 655 € /QALY:n välillä. Tämän järjestelmällisen kirjallisuuskatsauksen perusteella toisen polven virusspesifiset lääkkeet saattavat olla kustannusvaikuttavia standardihoitoon tai muuhun aktiivihoitoon verrattuna. Toisen polven virusspesifisten lääkkeiden ICER euroa per QALY oli alhaisempi maksavaurion vakavuuden lisääntyessä. Lääkeyritysten rahoittamissa tutkimuksissa ICER oli keskimäärin alhaisempi kuin muun tahon rahoittamissa tutkimuksissa. Järjestelmälliseen kirjallisuuskatsaukseen sisällytettyjen tutkimusten laatu vaihteli, mikä vaikeuttaa tulosten tulkintaa ja luotettavien johtopäätösten tekemistä. Tutkielman vahvuutena on järjestelmällisesti ja läpinäkyvästi toteutettu kirjallisuushaku, laadunarviointi ja tulosten raportointi. Heikkoutena on yhden henkilön suorittama kirjallisuuskatsaukseen sisällytettyjen tutkimusten valinta, tiedonkeruu ja laadunarviointi, jolloin inhimillisen virheen mahdollisuus kasvaa.
  • Bäckström, Mia (2017)
    Background: Dexmedetomdine is a α2–adrenergic receptor agonist, which by binding to the α2–adrenergic receptor in the sympathetic nervous system exhibits sedative effect. Additionally, it has an analgesic and anxiolytic effect. Dexmedetomidine is registered as a sedative for use in the intensive care unit and in USA, additionally, in surgical settings. The study was conducted to characterize the pharmacokinetics in healthy volunteers through pharmacokinetic analysis methods. Methods: The clinical study was conducted on healthy 10 voluntary subjects each receiving dose of 1 μg/kg both intravenously (IV) and subcutaneously (SC). The study session lasted for 10 hours, with a wash-out period of at least 7 days between consecutive administrations. Arterial blood samples were taken to determine the plasma concentrations of dexmedetomidine. The pharmacokinetics of the IV and SC dose were determined by noncompartmental analysis (NCA) and, additionally, population modeling using nonlinear mixed effects model (NONMEM) was used to determine the pharmacokinetics of the IV dose. Results: The population´s mean clearance after the IV dose was 40.0 L/h and for SC 45.6 L/h. The elimination half-life was 2 hours for IV, whereas terminal half-life was 9 hours for the SC dose. The SC bioavailability was 120 %. From the population modeling the typical elimination clearance, volume of distribution in central compartment, inter-compartmental clearance, and volume of distribution in the second compartment were 39.6 L/h, 13.7 L, 116 L/h, and 77 L, respectively. Conclussion: The obtained pharmacokinetic parameter values from NCA for IV were in line with the results from previous studies. For the SC dose the pharmacokinetic parameter values had high SD indicating high inter-individual variations. However, when the 8th subject was excluded from data analysis less SD was obtained and the result resembled more the results from other extravascular studies. The pharmacokinetic population results for IV dexmedetomidine were similar to previous studies on healthy subjects. Weight was used as a covariate, and was modeled by allometrically scaling the parameters. From the results it is shown that the covariate improved the model´s goodness of fit.
  • Tapanainen, Tuukka (2017)
    Asetyylikoliinin nikotiinireseptorien α5-alayksikkö osallistuu reseptorimuodostukseen rakenteellisena alayksikkönä. Se muuttaa reseptorin rakenteellisia ja toiminnallisia ominaisuuksia esimerkiksi kasvattamalla niiden läpäisevyyttä kalsiumille ja nopeuttamalla niiden desensitisaatiota. Nisäkkäiden aivoissa α5-alayksikön mRNA:ta ilmentyy eniten mustatumakkeen pars compactassa, ventraalisella tegmentaalialueella ja interpedunkulaaritumakkeessa. Sen proteiinia on tunnistettu olevan useilla eri aivoalueilla, kuten striatumissa, aivokuorella ja mediaalisessa habenulassa. α5-alayksikkö vaikuttaa motorisiin toimintoihin osallistuvassa dorsaalisessa striatumissa dopamiinin vapautumisen säätelyyn, jossa sen uskotaan säätelevän motorisia toimintoja. Tutkimuksen kokeellisessa osassa α5-poistogeenisille hiirille tehtiin toispuoleinen dopamiinihermosoluvaurio dorsaaliseen striatumiin 6-hydroksidopamiinilla (6-OHDA). Työn tarkoituksena oli selvittää α5-alayksikön osallisuus leesioinnin onnistumiseen ja motoriikan säätelyyn. α5-poistogeenisten ja villityypin hiirien motoriikkaa mitattiin amfetamiinilla ja apomorfiinilla aikaansaaduissa rotametriakokeissa. Rotametriakokeiden jälkeen hiiret lopetettiin ja niiden keskiaivoista määritettiin mustatumakkeen alueen dopamiinihermosolujen määrät mustatumakkeen mediaaliselta ja dorsaaliselta alueelta. Solulaskennan tarkoituksena oli määrittää 6-OHDA:lla tehdyn leesion laajuus ja selittää tutkimusryhmän aikaisempi havainto α5-poistogeenisten hiirten leesioinnin jälkeisestä vähäisemmästä amfetamiinin aiheuttamasta pyörimisestä vaurion suuntaan eli ipsilateraalisesti. α5-poistogeenisten hiirten havaittiin pyörivän amfetamiinilla aikaasaadussa rotametriakokeessa villityypin hiiriä vähemmän vaurion suuntaan ja apomorfiinilla aikaansaadussa rotametriakokeessa ensin villityypin hiiriä vähemmän ja lopuksi niitä enemmän vauriosta poispäin eli kontralateraalisesti. Pienempilukumääräisten urospuolisten hiirten tulokset jätettiin pois molemmista rotametriatuloksista, sillä villityypin hiirillä havaittiin sukupuolten välillä tilastollisesti merkitsevä ero amfetamiinilla aikaansaadussa rotametriakokeessa. Solulaskennassa ei havaittu tilastollisesti merkitseviä eroja mustatumakkeen mediaalisessa eikä dorsaalisessa osassa genotyyppien välillä, vaikka villityypin hiirillä näyttikin olevan mediaalisella alueella vähemmän soluja jäljellä 6-OHDA-leesioinnin jälkeen. Havaitut erot pyörimiskäyttäytymisessä voivat johtua myös genotyyppien välisistä eroista striatumissa vapautuvan dopamiinin määrissä tai eroista striatumin dopamiinireseptorien määrissä tai toiminnassa. Saadut tulokset tukevat käsitystä, että α5-alayksikön sisältämät nikotiinireseptorit osallistuvat motoriikan säätelyyn..