44 resultados para 100-50 µm

em Helda - Digital Repository of University of Helsinki


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Venäjän kieleen on kautta historian lainautunut sanoja muista kielistä. Historian tapahtumat ovat vaikuttaneet siihen, mistä kielistä sanoja on lainautunut eri aikakausina. Viime vuosikymmeninä venäjän kieleen on tulvinut lainasanoja englannin kielestä yhteiskunnan eri alueille. Tiiviit poliittiset, taloudelliset ja kulttuurisuhteet maiden ja kansojen välillä ovat ulkoisia, ei-kielellisiä syitä sanojen lainaamiseen. Kielen osa-alueista sanasto on kaikista avoimin ulkoisille vaikutteille ja samalla se on alue, johon heijastuvat yhteiskunnassa tapahtuvat muutokset. Lainasanojen ilmaantumiselle kieleen on myös sisäisiä, kielellisiä syitä. Lainasanojen ilmaantumisessa kirjallisessa muodossa venäjän kieleen voidaan erottaa kolme tapaa: transplantaatio eli sitaattilaina, translitteraatio sekä käytännöllinen transkriptio, jossa jokainen vieraskielinen foneemi pyritään esittämään vastaavalla venäjän foneemilla, jolloin vieraskielisen sanan ääntämys säilyy mahdollisimman alkuperäisenä. Lider-sana on esimerkki käytännöllisestä transkriptiosta, jossa venäläinen kirjoitusasu vastaa englannin kielen ääntämystä. Tutkimuksen kohteena on englanninkielinen lainasana lider, joka on ilmaantunut venäjän kieleen jo 1800-luvun puolivälissä. Sana on johdettu verbistä lead, merkityksessä ’johtaa, olla johdossa’, ja siinä on muodostunut substantiivi leader, ’johtaja’. Tutkimusaineistoa varten on poimittu 100 poliittiseen kielenkäyttöön liittyvää lider-sanaa sähköisessä tietokannassa Integrumissa olevassa Izvestija-lehdestä kahtena eri ajanjaksona, vuoden 1994 alusta alkaen sekä vuoden 2004 alusta alkaen. Tutkimuksessa keskityttiin lider-sanan käyttöön poliittisessa kielenkäytössä, mutta tutkimusaineiston keräysvaiheessa kirjattiin ylös myös muilla aihealueilla esiintyneet lider-sanat niidenkin käytön tarkastelua varten. Tutkimusta varten tarkasteltiin, millaisia määrityksiä lider-sanalle löytyy erilaisista nykykielen sanakirjoista eri vuosikymmeniltä. Vanhin mukana oleva sanakirja on venäläis-suomalainen sanakirja vuodelta 1912, jossa lider-sana määritellään yhdellä sanalla, ’puolueenjohtaja’. Aineisto jaettiin myös kolmeen ryhmään maantieteellisen sijainnin mukaan: Venäjä, entiset neuvostotasavallat ja ulkomaat. Tällä haluttiin selvittää, käytetäänkö lider-sanaa enemmän ulkomaisten vai venäläisten tapahtumin yhteydessä. Tutkimuksessa ilmeni, että suurin osa lider-sanoista liittyi Venäjän tapahtumiin molempina tarkasteluajanjaksoina – v. 1994 osuus oli 54 % ja v. 2004 50 %. Tähän tulokseen vaikuttavat varmaankin v. 1993 joulukuussa pidetyt ensimmäiset parlamenttivaalit sekä vuoden 2003 joulukuussa pidetyt duuman vaalit. Tutkimuksessa lider-sana jaettiin seitsemään eri kategoriaan käyttöyhteytensä mukaan ja saatujen tulosten perusteella suuri9n osa sanoista kuului kategoriaan ”puolueen johtaja”, v. 1994 osuus oli 47 % ja v. 2004 oli 40 %. Lider-sanan käyttö on levinnyt myös monelle muulle alueelle: urheilu, liike-elämä, kulttuuri, taide, tiede ja tekniikka. Venäjän kieleen ilmaantuu koko ajan vieraskielisiä sanoja, mutta kaikki niistä eivät sopeudu eivätkä juurru kieleen. Lainasanan on täytettävä tiettyjä edellytyksiä, jotta sitä voitaisiin pitää kieleen sopeutuneena: mukautumien kielen foneettiseen järjestelmään, sopeutuminen kielen graafiseen järjestelmään, sopeutuminen kieliopilliseen ympäristöön, semanttinen vakiintuminen sekä vakiintuminen vähintään kahdelle temaattiselle alueelle. Lainasanan juurtumisesta ja sopeutumisesta ovat todisteena myös siitä johdetut sanat. Lider-sana täyttää kaikki em. ehdot, joten sitä voidaan pitää venäjän kieleen sopeutuneena ja juurtuneena.

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The neural basis of visual perception can be understood only when the sequence of cortical activity underlying successful recognition is known. The early steps in this processing chain, from retina to the primary visual cortex, are highly local, and the perception of more complex shapes requires integration of the local information. In Study I of this thesis, the progression from local to global visual analysis was assessed by recording cortical magnetoencephalographic (MEG) responses to arrays of elements that either did or did not form global contours. The results demonstrated two spatially and temporally distinct stages of processing: The first, emerging 70 ms after stimulus onset around the calcarine sulcus, was sensitive to local features only, whereas the second, starting at 130 ms across the occipital and posterior parietal cortices, reflected the global configuration. To explore the links between cortical activity and visual recognition, Studies II III presented subjects with recognition tasks of varying levels of difficulty. The occipito-temporal responses from 150 ms onwards were closely linked to recognition performance, in contrast to the 100-ms mid-occipital responses. The averaged responses increased gradually as a function of recognition performance, and further analysis (Study III) showed the single response strengths to be graded as well. Study IV addressed the attention dependence of the different processing stages: Occipito-temporal responses peaking around 150 ms depended on the content of the visual field (faces vs. houses), whereas the later and more sustained activity was strongly modulated by the observers attention. Hemodynamic responses paralleled the pattern of the more sustained electrophysiological responses. Study V assessed the temporal processing capacity of the human object recognition system. Above sufficient luminance, contrast and size of the object, the processing speed was not limited by such low-level factors. Taken together, these studies demonstrate several distinct stages in the cortical activation sequence underlying the object recognition chain, reflecting the level of feature integration, difficulty of recognition, and direction of attention.

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The early detection of hearing deficits is important to a child's development. However, examining small children with behavioural methods is often difficult. Research with ERPs (event-related potentials), recorded with EEG (electroencephalography), does not require attention or action from the child. Especially in children's ERP research, it is essential that the duration of a recording session is not too long. A new, faster optimum paradigm has been developed to record MMN (mismatch negativity), where ERPs to several sound features can be recorded in one recording session. This substantially shortens the time required for the experiment. So far, the new paradigm has been used in adult and school-aged children research. This study examines if MMN, LDN (late discriminative negativity) and P3a components can be recorded in two-year-olds with the new paradigm. The standard stimulus (p=0.50) was an 80 dB harmonic tone consisting of three harmonic frequencies (500 Hz, 1000 Hz and 1500 Hz) with a duration of 200 ms. The loudness deviants (p=0.067) were at a level of +6 dB or -6 dB compared to the standards. The frequency deviants (p=0.112) had a fundamental frequency of 550 or 454.4 Hz (small deviation), 625 or 400 Hz (medium deviation) or 750 or 333.3 Hz (large deviation). The duration deviants (p=0.112) had a duration of 175 ms (small deviation), 150 ms (medium deviation) or 100 ms (large deviation). The direction deviants (p=0.067) were presented from the left or right loudspeaker only. The gap deviant (p=0.067) included a 5-ms silent gap in the middle of the sound. Altogether 17 children participated in the experiment, of whom the data of 12 children was used in the analysis. ERP components were observed for all deviant types. The MMN was significant for duration and gap deviants. The LDN was significant for the large duration deviant and all other deviant types. No significant P3a was observed. These results indicate that the optimum paradigm can be used with two-year-olds. With this paradigm, data on several sound features can be recorded in a shorter time than with the previous paradigms used in ERP research.

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The purpose of the present study was to explore the associations between good self-rated health and economic and social factors in different regions among ageing people in the Päijät-Häme region in southern Finland. The data of this study were collected in 2002 as part of the research and development project Ikihyvä 2002 2012 (Good Ageing in Lahti region GOAL project). The baseline data set consisted of 2,815 participants born in 1926 30, 1936 40, and 1946 50. The response rate was 66 %. According to the previous studies, trust in other people and social participation as the main aspects of social capital are associated with self-rated health. In addition, socioeconomic position (SEP) and self-rated health are associated, but all SEP indicators do not have identical associations with health. However, there is a lack of knowledge of the health associations and regional differences with these factors, especially among ageing people. Regarding these questions, the present study gives new information. According to the results of this study, self-perceived adequacy of income was significantly associated with good self-rated health, especially in the urban areas. Similar associations were found in the rural areas, though education was also considered an important factor. Adequacy of income was an even stronger predictor of good health than the actual income. Women had better self-rated health than men only in the urban areas. The youngest respondents had quite equally better self-rated health than the others. Social participation and access to help when needed were associated with good self-rated health, especially in the urban area and the sparsely populated rural areas. The result was comparable in the rural population centres. The correlation of trust with self-rated health was significant in the urban area. High social capital was associated with good self-rated health in the urban area. The association was quite similar in the other areas, though it was statistically insignificant. High social capital consisted of co-existent high social participation and high trust. The association of traditionalism (low participation and high trust) with self-rated health was also substantial in the urban area. The associations of self-rated health with low social capital (low participation and low trust) and the miniaturisation of community (high participation and low trust) were less significant. From the forms of single participation, going to art exhibitions, theatre, movies, and concerts among women, and studying and self-development among men were positively related to self-rated health. Unexpectedly, among women, active participation in religious events and voluntary work was negatively associated with self-rated health. This may indicate a coping method with ill-health. As a whole, only minor variations in self-rated health were found between the areas. However, the significance of the factors associated with self-rated health varied according to the areas. Economic factors, especially self-perceived adequacy of income was strongly associated with good self-rated health. Also when adjusting for economic and several other background factors social factors (particularly high social capital, social participation, and access to help when needed) were associated with self-rated health. Thus, economic and social factors have a significant relation with the health of the ageing, and improving these factors may have favourable effects on health among ageing people.

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Clinical trials have shown that weight reduction with lifestyles can delay or prevent diabetes and reduce blood pressure. An appropriate definition of obesity using anthropometric measures is useful in predicting diabetes and hypertension at the population level. However, there is debate on which of the measures of obesity is best or most strongly associated with diabetes and hypertension and on what are the optimal cut-off values for body mass index (BMI) and waist circumference (WC) in this regard. The aims of the study were 1) to compare the strength of the association for undiagnosed or newly diagnosed diabetes (or hypertension) with anthropometric measures of obesity in people of Asian origin, 2) to detect ethnic differences in the association of undiagnosed diabetes with obesity, 3) to identify ethnic- and sex-specific change point values of BMI and WC for changes in the prevalence of diabetes and 4) to evaluate the ethnic-specific WC cutoff values proposed by the International Diabetes Federation (IDF) in 2005 for central obesity. The study population comprised 28 435 men and 35 198 women, ≥ 25 years of age, from 39 cohorts participating in the DECODA and DECODE studies, including 5 Asian Indian (n = 13 537), 3 Mauritian Indian (n = 4505) and Mauritian Creole (n = 1075), 8 Chinese (n =10 801), 1 Filipino (n = 3841), 7 Japanese (n = 7934), 1 Mongolian (n = 1991), and 14 European (n = 20 979) studies. The prevalence of diabetes, hypertension and central obesity was estimated, using descriptive statistics, and the differences were determined with the χ2 test. The odds ratios (ORs) or  coefficients (from the logistic model) and hazard ratios (HRs, from the Cox model to interval censored data) for BMI, WC, waist-to-hip ratio (WHR), and waist-to-stature ratio (WSR) were estimated for diabetes and hypertension. The differences between BMI and WC, WHR or WSR were compared, applying paired homogeneity tests (Wald statistics with 1 df). Hierarchical three-level Bayesian change point analysis, adjusting for age, was applied to identify the most likely cut-off/change point values for BMI and WC in association with previously undiagnosed diabetes. The ORs for diabetes in men (women) with BMI, WC, WHR and WSR were 1.52 (1.59), 1.54 (1.70), 1.53 (1.50) and 1.62 (1.70), respectively and the corresponding ORs for hypertension were 1.68 (1.55), 1.66 (1.51), 1.45 (1.28) and 1.63 (1.50). For diabetes the OR for BMI did not differ from that for WC or WHR, but was lower than that for WSR (p = 0.001) in men while in women the ORs were higher for WC and WSR than for BMI (both p < 0.05). Hypertension was more strongly associated with BMI than with WHR in men (p < 0.001) and most strongly with BMI than with WHR (p < 0.001), WSR (p < 0.01) and WC (p < 0.05) in women. The HRs for incidence of diabetes and hypertension did not differ between BMI and the other three central obesity measures in Mauritian Indians and Mauritian Creoles during follow-ups of 5, 6 and 11 years. The prevalence of diabetes was highest in Asian Indians, lowest in Europeans and intermediate in others, given the same BMI or WC category. The  coefficients for diabetes in BMI (kg/m2) were (men/women): 0.34/0.28, 0.41/0.43, 0.42/0.61, 0.36/0.59 and 0.33/0.49 for Asian Indian, Chinese, Japanese, Mauritian Indian and European (overall homogeneity test: p > 0.05 in men and p < 0.001 in women). Similar results were obtained in WC (cm). Asian Indian women had lower  coefficients than women of other ethnicities. The change points for BMI were 29.5, 25.6, 24.0, 24.0 and 21.5 in men and 29.4, 25.2, 24.9, 25.3 and 22.5 (kg/m2) in women of European, Chinese, Mauritian Indian, Japanese, and Asian Indian descent. The change points for WC were 100, 85, 79 and 82 cm in men and 91, 82, 82 and 76 cm in women of European, Chinese, Mauritian Indian, and Asian Indian. The prevalence of central obesity using the 2005 IDF definition was higher in Japanese men but lower in Japanese women than in their Asian counterparts. The prevalence of central obesity was 52 times higher in Japanese men but 0.8 times lower in Japanese women compared to the National Cholesterol Education Programme definition. The findings suggest that both BMI and WC predicted diabetes and hypertension equally well in all ethnic groups. At the same BMI or WC level, the prevalence of diabetes was highest in Asian Indians, lowest in Europeans and intermediate in others. Ethnic- and sex-specific change points of BMI and WC should be considered in setting diagnostic criteria for obesity to detect undiagnosed or newly diagnosed diabetes.

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Various reasons, such as ethical issues in maintaining blood resources, growing costs, and strict requirements for safe blood, have increased the pressure for efficient use of resources in blood banking. The competence of blood establishments can be characterized by their ability to predict the volume of blood collection to be able to provide cellular blood components in a timely manner as dictated by hospital demand. The stochastically varying clinical need for platelets (PLTs) sets a specific challenge for balancing supply with requests. Labour has been proven a primary cost-driver and should be managed efficiently. International comparisons of blood banking could recognize inefficiencies and allow reallocation of resources. Seventeen blood centres from 10 countries in continental Europe, Great Britain, and Scandinavia participated in this study. The centres were national institutes (5), parts of the local Red Cross organisation (5), or integrated into university hospitals (7). This study focused on the departments of blood component preparation of the centres. The data were obtained retrospectively by computerized questionnaires completed via Internet for the years 2000-2002. The data were used in four original articles (numbered I through IV) that form the basis of this thesis. Non-parametric data envelopment analysis (DEA, II-IV) was applied to evaluate and compare the relative efficiency of blood component preparation. Several models were created using different input and output combinations. The focus of comparisons was on the technical efficiency (II-III) and the labour efficiency (I, IV). An empirical cost model was tested to evaluate the cost efficiency (IV). Purchasing power parities (PPP, IV) were used to adjust the costs of the working hours and to make the costs comparable among countries. The total annual number of whole blood (WB) collections varied from 8,880 to 290,352 in the centres (I). Significant variation was also observed in the annual volume of produced red blood cells (RBCs) and PLTs. The annual number of PLTs produced by any method varied from 2,788 to 104,622 units. In 2002, 73% of all PLTs were produced by the buffy coat (BC) method, 23% by aphaeresis and 4% by the platelet-rich plasma (PRP) method. The annual discard rate of PLTs varied from 3.9% to 31%. The mean discard rate (13%) remained in the same range throughout the study period and demonstrated similar levels and variation in 2003-2004 according to a specific follow-up question (14%, range 3.8%-24%). The annual PLT discard rates were, to some extent, associated with production volumes. The mean RBC discard rate was 4.5% (range 0.2%-7.7%). Technical efficiency showed marked variation (median 60%, range 41%-100%) among the centres (II). Compared to the efficient departments, the inefficient departments used excess labour resources (and probably) production equipment to produce RBCs and PLTs. Technical efficiency tended to be higher when the (theoretical) proportion of lost WB collections (total RBC+PLT loss) from all collections was low (III). The labour efficiency varied remarkably, from 25% to 100% (median 47%) when working hours were the only input (IV). Using the estimated total costs as the input (cost efficiency) revealed an even greater variation (13%-100%) and overall lower efficiency level compared to labour only as the input. In cost efficiency only, the savings potential (observed inefficiency) was more than 50% in 10 departments, whereas labour and cost savings potentials were both more than 50% in six departments. The association between department size and efficiency (scale efficiency) could not be verified statistically in the small sample. In conclusion, international evaluation of the technical efficiency in component preparation departments revealed remarkable variation. A suboptimal combination of manpower and production output levels was the major cause of inefficiency, and the efficiency did not directly relate to production volume. Evaluation of the reasons for discarding components may offer a novel approach to study efficiency. DEA was proven applicable in analyses including various factors as inputs and outputs. This study suggests that analytical models can be developed to serve as indicators of technical efficiency and promote improvements in the management of limited resources. The work also demonstrates the importance of integrating efficiency analysis into international comparisons of blood banking.

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Intracranial artery aneurysms (IAs) are estimated to be present in 2.3% of the population. A rupture of an IA causes subarachnoid hemorrhage, with up to 50% mortality. The annual low rupture risk of an IA indicates that most IAs never rupture. The current treatment options are invasive and somewhat risky. Thus rupture-prone IAs should be identified and this requires a better understanding of the IA wall pathobiology. Inflammatory cell infiltrations have been found to precede IA rupture, indicating the role of inflammation in IA wall degeneration and rupture. The complement system is a key mediator of inflammation and house-hold processing of injured tissue. This study aimed at identifying the role of complement activation in IA wall degeneration and the complement activators involved and determining how the complement system is regulated in the IA wall. In immunostainings, the end-product of complement activation, the terminal complement complex (TCC), was located mainly in the outer part of the IA wall, in areas that had also sustained loss of cells. In electron microscopy, the area of maximum TCC accumulation contained cellular debris and evidence of both apoptotic and necrotic cell death. Complement activation correlated with IA wall degeneration and rupture, de-endothelialization, and T-cell and CD163-positive macrophage infiltration. The complement system was found to become activated in all IAs by the classical pathway, with recruitment of alternative pathway amplification. Of the potential activators immunoglobulins G and M and oxidatively modified lipids were found in large areas. Lipid accumulation was observed to clearly colocalize with TCC and C-reactive protein. In the luminal parts of the IA wall, complement activation was limited by cellular expression of protectin (CD59) and extracellular matrix-bound inhibitors, C4b binding protein and factor H whereas the outer part of the wall lacked cells expressing protectin as well as matrix-bound factor H. In single nucleotide polymorphism-analysis, age-related macular degeneration-associated factor H Y402H polymorphism did not associate with the presence of IAs or their rupture The data suggest that complement activation and TCC formation are involved in IA wall degeneration and rupture. Complement seems to become activated by more than one specific activator. The association of complement with de-endothelialization and expression of several complement activators indicate a possible role of endothelial dysfunction and/or impaired clearance mechanisms. Impaired complement regulation seems to be associated with increased complement activation in IA walls. These results stress the role of chronic inflammation in IA wall pathobiology and the regulatory role of complement within this process. Imaging inflammation would possibly enhance the diagnostics of rupture-prone IAs, and targeting IA treatment to prevent chronic inflammation might improve IA treatment in the future.

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Infection by Epstein-Barr virus (EBV) occurs in approximately 95% of the world s population. EBV was the first human virus implicated in oncogenesis. Characteristic for EBV primary infection are detectable IgM and IgG antibodies against viral capsid antigen (VCA). During convalescence the VCA IgM disappears while the VCA IgG persists for life. Reactivations of EBV occur both among immunocompromised and immunocompetent individuals. In serological diagnosis, measurement of avidity of VCA IgG separates primary from secondary infections. However, in serodiagnosis of mononucleosis it is quite common to encounter, paradoxically, VCA IgM together with high-avidity VCA IgG, indicating past immunity. We determined the etiology of this phenomenon and found that, among patients with cytomegalovirus (CMV) primary infection a large proportion (23%) showed antibody profiles of EBV reactivation. In contrast, EBV primary infection did not appear to induce immunoreactivation of CMV. EBV-associated post-transplant lymphoproliferative disease (PTLD) is a life threatening complication of allogeneic stem cell or solid organ transplantation. PTLD may present with a diverse spectrum of clinical symptoms and signs. Due to rapidity of PTLD progression especially after stem cell transplantation, the diagnosis must be obtained quickly. Pending timely detection, the evolution of the fatal disease may be halted by reduction of immunosuppression. A promising new PTLD treatment (also in Finland) is based on anti-CD-20 monoclonal antibodies. Diagnosis of PTLD has been demanding because of immunosuppression, blood transfusions and the latent nature of the virus. We set up in 1999 to our knowledge first in Finland for any microbial pathogen a real-time quantitative PCR (qPCR) for detection of EBV DNA in blood serum/plasma. In addition, we set up an in situ hybridisation assay for EBV RNA in tissue sections. In collaboration with a group of haematologists at Helsinki University Central Hospital we retrospectively determined the incidence of PTLD among 257 allogenic stem cell transplantations (SCT) performed during 1994-1999. Post-mortem analysis revealed 18 cases of PTLD. From a subset of PTLD cases (12/18) and a series of corresponding controls (36), consecutive samples of serum were studied by the new EBV-qPCR. All the PTLD patients were positive for EBV-DNA with progressively rising copy numbers. In most PTLD patients EBV DNA became detectable within 70 days of SCT. Of note, the appearance of EBV DNA preceded the PTLD symptoms (fever, lymphadenopathy, atypical lymphocytes). Among the SCT controls, EBV DNA occurred only sporadically, and the EBV-DNA levels remained relatively low. We concluded that EBV qPCR is a highly sensitive (100%) and specific (96%) new diagnostic approach. We also looked for and found risk factors for the development of PTLD. Together with a liver transplantation group at the Transplantation and Liver Surgery Clinic we wanted to clarify how often and how severely do EBV infections occur after liver transplantation. We studied by the EBV qPCR 1284 plasma samples obtained from 105 adult liver transplant recipients. EBV DNA was detected in 14 patients (13%) during the first 12 months. The peak viral loads of 13 asymptomatic patients were relatively low (<6600/ml), and EBV DNA subsided quickly from circulation. Fatal PTLD was diagnosed in one patient. Finally, we wanted to determine the number and clinical significance of EBV infections of various types occurring among a large, retrospective, nonselected cohort of allogenic SCT recipients. We analysed by EBV qPCR 5479 serum samples of 406 SCT recipients obtained during 1988-1999. EBV DNA was seen in 57 (14%) patients, of whom 22 (5%) showed progressively rising and ultimately high levels of EBV DNA (median 54 million /ml). Among the SCT survivors, EBV DNA was transiently detectable in 19 (5%) asymptomatic patients. Thereby, low-level EBV-DNA positivity in serum occurs relatively often after SCT and may subside without specific treatment. However, high molecular copy numbers (>50 000) are diagnostic for life-threatening EBV infection. We furthermore developed a mathematical algorithm for the prediction of development of life-threatening EBV infection.

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Sindbis virus (SINV) (genus Alphavirus, family Togaviridae) is an enveloped virus with a genome of single-stranded, positive-polarity RNA of 11.7 kilobases. SINV is widespread in Eurasia, Africa, and Australia, but clinical infection only occurs in a few geographically restricted areas, mainly in Northern Europe. In Europe, antibodies to SINV were detected from patients with fever, rash, and arthritis for the first time in the early 1980s in Finland. It became evident that the causative agent of this syndrome, named Pogosta disease, was closely related to SINV. The disease is also found in Sweden (Ockelbo disease) and in Russia (Karelian fever). Since 1974, for unknown reason, the disease has occurred as large outbreaks every seven years in Finland. This study is to a large degree based on the material collected during the 2002 Pogosta disease outbreak in Finland. We first developed SINV IgM and IgG enzyme immunoassays (EIA), based on highly purified SINV, to be used in serodiagnostics. The EIAs correlated well with the hemagglutination inhibition (HI) test, and all individuals showed neutralizing antibodies. The sensitivities of the IgM and IgG EIAs were 97.6% and 100%, and specificities 95.2% and 97.6%, respectively. E1 and E2 envelope glycoproteins of SINV were shown to be recognized by IgM and IgG in the immunoblot early in infection. We isolated SINV from five patients with acute Pogosta disease; one virus strain was recovered from whole blood, and four other strains from skin lesions. The etiology of Pogosta disease was confirmed by these first Finnish SINV strains, also representing the first human SINV isolates from Europe. Phylogenetic analysis indicated that the Finnish SINV strains clustered with the strains previously isolated from mosquitoes in Sweden and Russia, and seemed to have a common ancestor with South-African strains. Northern European SINV strains could be maintained locally in disease-endemic regions, but the phylogenetic analysis also suggests that redistribution of SINV tends to occur in a longitudinal direction, possibly with migratory birds. We searched for SINV antibodies in resident grouse (N=621), whose population crashes have previously coincided with human SINV outbreaks, and in migratory birds (N=836). SINV HI antibodies were found for the first time in birds during their spring migration to Northern Europe, from three individuals: red-backed shrike, robin, and song thrush. Of the grouse, 27.4% were seropositive in 2003, one year after a human outbreak, but only 1.4% of the grouse were seropositive in 2004. Thus, grouse might contribute to the human epidemiology of SINV. A total of 86 patients with verified SINV infection were recruited to the study in 2002. SINV RNA detection or virus isolation from blood and/or skin lesions was successful in eight patients. IgM antibodies became detectable within the first eight days of illness, and IgG within 11 days. The acute phase of Pogosta disease was characterized by arthritis, itching rash, fatigue, mild fever, headache, and muscle pain. Half of the patients reported in self-administered questionnaires joint symptoms to last > 12 months. Physical examination in 49 of these patients three years after infection revealed persistent joint manifestations. Arthritis (swelling and tenderness in physical examination) was diagnosed in 4.1% (2/49) of the patients. Tenderness in palpation or in movement of a joint was found in 14.3% of the patients in the rheumatologic examination, and additional 10.2% complained persisting arthralgia at the interview. Thus, 24.5% of the patients had joint manifestations attributable to the infection three years earlier. A positive IgM antibody response persisted in 3/49 of the patients; both two patients with arthritis were in this group. Persistent symptoms of SINV infection might have considerable public health implications in areas with high seroprevalence. The age-standardized seroprevalence of SINV (1999-2003, N=2529) in the human population in Finland was 5.2%. The seroprevalence was high in North Karelia, Kainuu, and Central Ostrobothnia. The incidence was highest in North Karelia. Seroprevalence in men (6.0%) was significantly higher than in women (4.1%), however, the average annualized incidence in the non-epidemic years was higher in women than in men, possibly indicating that infected men are more frequently asymptomatic. The seroprevalence increased with age, reaching 15.4% in persons aged 60-69 years. The incidence was highest in persons aged 50-59 years.

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The von Hippel-lindau (VHL) disease is a dominantly inherited neoplastic disorder which predisposes patients to multiple tumours including capillary haemangioblastomas (CHBs), pheochromocytomas (PCCs), renal cell carcinomas (RCCs). CHBs are the most common manifestations of VHL disease, occurring sporadically or as a manifestation of VHL disease. Inactivation of the VHL gene at 3p25-26 is believed to cause both familial and sporadic VHL-associated tumours and germ-line mutation of the VHL gene have been detected in 100% of the CHBs studied. However, a limited number of sporadic CHBs, PCCs display VHL inactivation. Other molecular alterations involved in tumourigenesis of sporadic CHBs, PCCs remain largely unknown. The purpose of the present work was to search for genetic alterations, or other mechanisms of inactivation, in addition to the VHL gene, that may be important in the development of VHL-associated tumours. Though less satisfactory than cure, prevention and early detection are the most promising and feasible means reducing cancer morbidity and mortality. This work is based on the view that increasing knowledge about the molecular events underlying tumour development will eventually aid in early detection and lead to improved treatment. We evaluated a large set of VHL-associated patients, searched for a clinical and radiologic signs of the disease. We succesfully performed a germ-line mutation analysis and characterised three patient groups, VHL, suspect VHL and sporadic, a germ-line mutation analysis revealed a 50% mutation rate only in the VHL groups, no sporadic or suspect cases displayed any mutation. We also utilized comparative genomic hybridization (CGH) to screen for DNA copy number changes in both sporadic and VHL-associated CHB. Our analysis revealed (27%) DNA copy number losses. The most common finding was loss of chromosomal arm 6q, seen in (23%) cases, No differences were noted between VHL-associated and sporadic tumours. Furthermore a loss of heterozygosity (LOH) study on chromosome 3p and 6q was done with the purpose to determine allele losses not observable by CGH, and to uncover the location of putative tumour suppressor genes important in CHB and PCC tumourigenesis. We identified loss of chromosome 6q and a minimal deleted area at 6q23-24 in CHBs. We also showed LOH at 6q23-24 in PCCs and identified the ZAC1 (6q24-25) as a candidate gene, ZAC1 is a maternally imprinted tumour suppressor gene with anti proliferative properties. To study further the role of ZAC inactivation in CHBs, we investigated LOH, promoter hypermethylation and expression status of the ZAC1 gene in mainly sporadic CHBs. Our LOH analysis revealed that the majority of the tumours with allele loss. The gene promoter methylation analysis similarly detected predominance of the methylated ZAC sequence in almost all tumours. Immunohistochemistry exhibited a strongly reduced expression of ZAC in stromal cells of all CHBs studied. Our current results indicate that the absence of the unmethylated, ZAC1 promoter sequence was highly concurrent with LOH for the ZAC1 region or 6q loss. This observation together with lack of ZAC expression, points to preferential loss of the non imprinted, expressed ZAC allele in CHB, in summary, our series of studies reveal a new chromosomal region 6q, emphasizes the importance of ZAC1 gene in the development of CHB and PCC, particularly in non-VHL associated cases.

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Dengue is a mosquito-borne viral disease caused by the four dengue virus serotypes (DENV-1-4) and is currently considered as the most important arthropod-borne viral disease in the world. Nearly half of the human population lives in risk areas, and 50-100 million infections occur yearly according to World Health Organization. The disease can vary from a mild febrile disease to severe haemorrhagic fever and shock. A secondary infection with heterologous serotype increases the risk for severe disease outcome. During the last three decades the impact of dengue has dramatically increased in the endemic areas including the tropics and subtropics of the world. The current situation with massive epidemics of severe disease forms has been associated with socio-ecological changes that have increased the transmission and enabled the co-circulation of different serotypes. Consequently, an increase of dengue has also been observed in travelers visiting these areas. Currently approximately 30 cases are diagnosed yearly in Finnish travelers. In travelers dengue is rarely a life-threatening disease, however in the current study, a fatality was documented in a young Finnish patient who experienced a prolonged primary dengue infection. To improve particularly early laboratory diagnostics, a novel real-time RT-PCR method was developed for the detection of DENV-1-4 RNA based on TaqMan chemistry. The method was shown to be sensitive and specific for detecting DENV RNA and suitable for diagnostic use. The newly developed real-time RT-PCR was compared to other available early diagnostic methods including IgM and NS1 antigen detection using a panel of selected patient samples. The results suggest that the best diagnostic rates are achieved by a combination of IgM with RNA or NS1 detection. The dengue virus strains studied here included the first DENV strains isolated from serum samples of Finnish travelers collected in 2000-2005. The results of sequence analysis demonstrated that the 11 isolates included all four DENV serotypes and presented a global sample of DENV strains from different geographical areas including Asia, Africa and South America. In the present study sequence analysis was also carried out for a collection of 23 novel DENV-2 isolates from Venezuelan patients collected in 1999-2005. The Venezuelan DENV-2 exclusively represented the American-Asian genotype, suggesting that no foreign DENV-2 lineages have recently been introduced to the country. The results also suggest that the DENV-2 viruses detected earlier from Venezuela have been maintained in the area where they have evolved into several lineages. This is in contrast to the pattern observed in some other dengue endemic areas, where introductions of novel virus types and lineages are frequently detected.

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The objectives of this study were to investigate the stand structure and succession dynamics in Scots pine (Pinus sylvestris L.) stands on pristine peatlands and in Scots pine and Norway spruce (Picea abies (L.) Karst.) dominated stands on drained peatlands. Furthermore, my focus was on characterising how the inherent and environmental factors and the intermediate thinnings modify the stand structure and succession. For pristine peatlands, the study was based on inventorial stand data, while for drained peatlands, longitudinal data from repeatedly measured stands were utilised. The studied sites covered the most common peatland site types in Finland. They were classified into two categories according to the ecohydrological properties related to microsite variation and nutrient levels within sites. Tree DBH and age distributions in relation to climate and site type were used to study the stand dynamics on pristine sites. On drained sites, the Weibull function was used to parameterise the DBH distributions and mixed linear models were constructed to characterise the impacts of different ecological factors on stand dynamics. On pristine peatlands, both climate and the ecohydrology of the site proved to be crucial factors determining the stand structure and its dynamics. Irrespective of the vegetation succession, enhanced site productivity and increased stand stocking they significantly affected the stand dynamics also on drained sites. On the most stocked sites on pristine peatlands the inter-tree competition seemed to also be a significant factor modifying stand dynamics. Tree age and size diversity increased with stand age, but levelled out in the long term. After drainage, the stand structural unevenness increased due to the regeneration and/or ingrowth of the trees. This increase was more pronounced on sparsely forested composite sites than on more fully stocked genuine forested sites in Scots pine stands, which further undergo the formation of birch and spruce undergrowth beneath the overstory as succession proceeds. At 20-30 years after drainage the structural heterogeneity started to decrease, indicating increased inter-tree competition, which increased the mortality of suppressed trees within stand. Peatland stands are more dynamic than anticipated and are generally not characterized by a balanced, self-perpetuating structure. On pristine sites, various successional pathways are possible, whereas on drained sites the succession has more uniform trend. Typically, stand succession proceeds without any distinct developmental stages on pristine peatlands, whereas on drained peatlands, at least three distinct stages could be identified. Thinnings had only little impact on the stand succession. The new information on stand dynamics may be utilised, e.g. in forest management planning to facilitate the allocation of the growth resources to the desired crop component by appropriate silvicultural treatments, as well as assist in assessing the effects of the climate change on the forested boreal peatlands.

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B. cereus is a gram-positive bacterium that possesses two different forms of life:the large, rod-shaped cells (ca. 0.002 mm by 0.004 mm) that are able to propagate and the small (0.001 mm), oval shaped spores. The spores can survive in almost any environment for up to centuries without nourishment or water. They are insensitive towards most agents that normally kill bacteria: heating up to several hours at 90 ºC, radiation, disinfectants and extreme alkaline (≥ pH 13) and acid (≤ pH 1) environment. The spores are highly hydrophobic and therefore make them tend to stick to all kinds of surfaces, steel, plastics and live cells. In favorable conditions the spores of B. cereus may germinate into vegetative cells capable of producing food poisoning toxins. The toxins can be heat-labile protein formed after ingestion of the contaminated food, inside the gastrointestinal tract (diarrhoeal toxins), or heat stable peptides formed in the food (emesis causing toxin, cereulide). Cereulide cannot be inactivated in foods by cooking or any other procedure applicable on food. Cereulide in consumed food causes serious illness in human, even fatalities. In this thesis, B. cereus strains originating from different kinds of foods and environments and 8 different countries were inspected for their capability of forming cereulide. Of the 1041 isolates from soil, animal feed, water, air, used bedding, grass, dung and equipment only 1.2 % were capable of producing cereulide, whereas of the 144 isolates originating from foods 24 % were cereulide producers. Cereulide was detected by two methods: by its toxicity towards mammalian cells (sperm assay) and by its peculiar chemical structure using liquid-chromatograph-mass spectrometry equipment. B. cereus is known as one of the most frequent bacteria occurring in food. Most foods contain more than one kind of B. cereus. When randomly selected 100 isolates of B. cereus from commercial infant foods (dry formulas) were tested, 11% of these produced cereulide. Considering a frequent content of 103 to 104 cfu (colony forming units) of B. cereus per gram of infant food formula (dry), it appears likely that most servings (200 ml, 30 g of the powder reconstituted with water) may contain cereulide producers. When a reconstituted infant formula was inoculated with >105 cfu of cereulide producing B. cereus per ml and left at room temperature, cereulide accumulated to food poisoning levels (> 0.1 mg of cereulide per serving) within 24 hours. Paradoxically, the amount of cereulide (per g of food) increased 10 to 50 fold when the food was diluted 4 - 15 fold with water. The amount of the produced cereulide strongly depended on the composition of the formula: most toxin was formed in formulas with cereals mixed with milk, and least toxin in formulas based on milk only. In spite of the aggressive cleaning practices executed by the modern dairy industry, certain genotypes of B. cereus appear to colonise the silos tanks. In this thesis four strategies to explain their survival of their spores in dairy silos were identified. First, high survival (log 15 min kill ≤ 1.5) in the hot alkaline (pH >13) wash liquid, used at the dairies for cleaning-in-place. Second, efficient adherence of the spores to stainless steel from cold water. Third, a cereulide producing group with spores characterized by slow germination in rich medium and well preserved viability when exposed to heating at 90 ºC. Fourth, spores capable of germinating at 8 ºC and possessing the psychrotolerance gene, cspA. There were indications that spores highly resistant to hot 1% sodium hydroxide may be effectively inactivated by hot 0.9% nitric acid. Eight out of the 14 dairy silo tank isolates possessing hot alkali resistant spores were capable of germinating and forming biofilm in whole milk, not previously reported for B. cereus. In this thesis it was shown that cereulide producing B. cereus was capable of inhibiting the growth of cereulide non-producing B. cereus occurring in the same food. This phenomenon, called antagonism, has long been known to exist between B. cereus and other microbial species, e.g. various species of Bacillus, gram-negative bacteria and plant pathogenic fungi. In this thesis intra-species antagonism of B. cereus was shown for the first time. This brother-killing did not depend on the cereulide molecule, also some of the cereulide non-producers were potent antagonists. Interestingly, the antagonistic clades were most frequently found in isolates from food implicated with human illness. The antagonistic property was therefore proposed in this thesis as a novel virulence factor that increases the human morbidity of the species B. cereus, in particular of the cereulide producers.

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This doctoral thesis describes the development of a miniaturized capillary electrochromatography (CEC) technique suitable for the study of interactions between various nanodomains of biological importance. The particular focus of the study was low-density lipoprotein (LDL) particles and their interaction with components of the extracellular matrix (ECM). LDL transports cholesterol to the tissues through the blood circulation, but when the LDL level becomes too high the particles begin to permeate and accumulate in the arteries. Through binding sites on apolipoprotein B-100 (apoB-100), LDL interacts with components of the ECM, such as proteoglycans (PGs) and collagen, in what is considered the key mechanism in the retention of lipoproteins and onset of atherosclerosis. Hydrolytic enzymes and oxidizing agents in the ECM may later successively degrade the LDL surface. Metabolic diseases such as diabetes may provoke damage of the ECM structure through the non-enzymatic reaction of glucose with collagen. In this work, fused silica capillaries of 50 micrometer i.d. were successfully coated with LDL and collagen, and steroids and apoB-100 peptide fragments were introduced as model compounds for interaction studies. The LDL coating was modified with copper sulphate or hydrolytic enzymes, and the interactions of steroids with the native and oxidized lipoproteins were studied. Lipids were also removed from the LDL particle coating leaving behind an apoB-100 surface for further studies. The development of collagen and collagen decorin coatings was helpful in the elucidation of the interactions of apoB-100 peptide fragments with the primary ECM component, collagen. Furthermore, the collagen I coating provided a good platform for glycation studies and for clarification of LDL interactions with native and modified collagen. All methods developed are inexpensive, requiring just small amounts of biomaterial. Moreover, the experimental conditions in CEC are easily modified, and the analyses can be carried out in a reasonable time frame. Other techniques were employed to support and complement the CEC studies. Scanning electron microscopy and atomic force microscopy provided crucial visual information about the native and modified coatings. Asymmetrical flow field-flow fractionation enabled size measurements of the modified lipoproteins. Finally, the CEC results were exploited to develop new sensor chips for a continuous flow quartz crystal microbalance technique, which provided complementary information about LDL ECM interactions. This thesis demonstrates the potential of CEC as a valuable and flexible technique for surface interaction studies. Further, CEC can serve as a novel microreactor for the in situ modification of LDL and collagen coatings. The coatings developed in this study provide useful platforms for a diversity of future investigations on biological nanodomains.

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Palaeoenvironments of the latter half of the Weichselian ice age and the transition to the Holocene, from ca. 52 to 4 ka, were investigated using isotopic analysis of oxygen, carbon and strontium in mammal skeletal apatite. The study material consisted predominantly of subfossil bones and teeth of the woolly mammoth (Mammuthus primigenius Blumenbach), collected from Europe and Wrangel Island, northeastern Siberia. All samples have been radiocarbon dated, and their ages range from >52 ka to 4 ka. Altogether, 100 specimens were sampled for the isotopic work. In Europe, the studies focused on the glacial palaeoclimate and habitat palaeoecology. To minimise the influence of possible diagenetic effects, the palaeoclimatological and ecological reconstructions were based on the enamel samples only. The results of the oxygen isotope analysis of mammoth enamel phosphate from Finland and adjacent nortwestern Russia, Estonia, Latvia, Lithuania, Poland, Denmark and Sweden provide the first estimate of oxygen isotope values in glacial precipitation in northern Europe. The glacial precipitation oxygen isotope values range from ca. -9.2±1.5 in western Denmark to -15.3 in Kirillov, northwestern Russia. These values are 0.6-4.1 lower than those in present-day precipitation, with the largest changes recorded in the currently marine influenced southern Sweden and the Baltic region. The new enamel-derived oxygen isotope data from this study, combined with oxygen isotope records from earlier investigations on mammoth tooth enamel and palaeogroundwaters, facilitate a reconstruction of the spatial patterns of the oxygen isotope values of precipitation and palaeotemperatures over much of Europe. The reconstructed geographic pattern of oxygen isotope levels in precipitation during 52-24 ka reflects the progressive isotopic depletion of air masses moving northeast, consistent with a westerly source of moisture for the entire region, and a circulation pattern similar to that of the present-day. The application of regionally varied δ/T-slopes, estimated from palaeogroundwater data and modern spatial correlations, yield reasonable estimates of glacial surface temperatures in Europe and imply 2-9°C lower long-term mean annual surface temperatures during the glacial period. The isotopic composition of carbon in the enamel samples indicates a pure C3 diet for the European mammoths, in agreement with previous investigations of mammoth ecology. A faint geographical gradient in the carbon isotope values of enamel is discernible, with more negative values in the northeast. The spatial trend is consistent with the climatic implications of the enamel oxygen isotope data, but may also suggest regional differences in habitat openness. The palaeogeographical changes caused by the eustatic rise of global sea level at the end of the Weichselian ice age was investigated on Wrangel Island, using the strontium isotope (Sr-87/Sr-86) ratios in the skeletal apatite of the local mammoth fauna. The diagenetic evaluations suggest good preservation of the original Sr isotope ratios, even in the bone specimens included in the study material. To estimate present-day environmental Sr isotope values on Wrangel Island, bioapatite samples from modern reindeer and muskoxen, as well as surface waters from rivers and ice wedges were analysed. A significant shift towards more radiogenic bioapatite Sr isotope ratios, from 0.71218 ± 0.00103 to 0.71491 ± 0.00138, marks the beginning of the Holocene. This implies a change in the migration patterns of the mammals, ultimately reflecting the inundation of the mainland connection and isolation of the population. The bioapatite Sr isotope data supports published coastline reconstructions placing the time of separation from the mainland to ca. 10-10.5 ka ago. The shift towards more radiogenic Sr isotope values in mid-Holocene subfossil remains after 8 ka ago reflects the rapid rise of the sea level from 10 to 8 ka, resulting in a considerable reduction of the accessible range area on the early Wrangel Island.