Browsing by Title

Sort by: Order: Results:

Now showing items 3182-3201 of 28481
  • Silfver, Olga (2008)
    This study examines the immigration reasons, the process of choosing the country and acculturation strategies of highly educated post-Soviet employees working in Finland. The main research questions of this study are: 1. Why do post-Soviet professionals leave their home countries? 2. Do post-Soviet highly educated professionals perceive they have a choice as far as their migration is concerned? 3. Why do the post-Soviet professionals choose Finland as the country of residence? 4. What is the main acculturation strategy for post-Soviet professionals in Finland, and why`? The thesis is a qualitative study that uses ten half-structured interviews as its material. It combines different theoretical perspectives: acculturation theory, thesis of global professionals, Bourdieu's concepts on transformation of resources and theories of cultural and ethnic identity. This study interprets the decision to immigrate and integration of the respondents as resource optimisation, ,where skills, networks, positions and cultural competences are used to achieve the best attainable position for the family. The main reason for the respondents to leave a home country was economic refuge. Social instability and search for better opportunities were also important factors. The majority of my respondents did not perceive to have a choice of country of immigration. Those who had selected Finland consciously did so due to networks or geographical proximity of the country. Mostly though, Finland was not well-known among highly educated post-Soviets, so the selection of Finland could be attributed ,more to a coincidence than to conscious Finnish state policy. The study emphasizes the sphere of work, since my respondents spend considerable portion of their daily time there and since workplace is an important integrating institution for work-related immigrants. The research concludes that the workplaces of the respondents are currently unable to fully support the needs of immigrant labour force. Commonly used short-term contracts cause a lack of stability, which lowers the motivation to integrate. I have discerned two processes operating in workplaces, selective racist labelling and double-level acceptance process, which both influence the process of integration of immigrants. Post-Soviet immigrants adopt a separatory acculturation strategy due to strong post-Soviet identity and rather slowly developing Finnish skills. They prefer to socialise with the Russian-speaking people, which has a negative effect on the speed of their integration into Finnish society. Global professionals have an additional slowing factor, i.e. poor motivation for language studies as long as the change of country is probable. Discriminatory attitudes of not only locals and post-Soviets, but also of post-Soviets towards other minorities ,strengthen the separatory acculturation strategy. All in all, I perceive my study group as a highly potential resource for the Finnish dwindling labour markets. They are attracted to Finnish orderliness, respect to law, and closeness of nature. However, the limitations of ,their legal status and the resulting instability, lack of knowledge and insufficient communication with local population pose challenges for their integration. In order to produce long-term advantages from immigrating workforce and avoid the problems of segregated society, these shortcomings have to be mitigated.
  • Luukkonen, Helka (1969)
  • Ylä-Outinen, Urho (1953)
  • Kashif, Muhammad (Helsingfors universitet, 2012)
    Sweetpotato is a subsistence crop for many thousands of families across the globe. The present studies in the thesis provide basic knowledge about Sweet potato chlorotic stunt virus (SPCSV) and Sweet potato feathery mottle virus (SPFMV) that were detected and characterized from sweetpotatoes in Guatemala and Honduras. Sweetpotato plants from Central American countries were showing typical virus-like symptoms. Different strategies were adopted for virus detection. SPCSV and SPFMV were found to be infecting sweetpotato plants. SPFMV was detected only in sweetpotato plants from Honduras. SPFMV infection was detected serologically and results were confirmed by RT-PCR and sequencing. A recently developed detection method, based on restrictotypes of PCR products by two different endonucleases, revealed co-infection of SPFMV strains C and RC in a sweetpotato plant from Honduras which was corroborated by sequencing 3'-proximal end (1.8 kb) of the genome and the coat protein (CP) ~940 nt based phylogenetic analysis. SPCSV was detected by double-stranded RNA extraction, confirmed by RT-PCR and subsequent sequencing of the partial HSP70h gene of genomic RNA2 gene of SPCSV. Phylogenetic analysis was done by constructing neighbour-joining tree of aligned nucleotide sequences, including SPCSV-EA isolates and SPCSV-WA isolates from database that clearly differentiated SPCSV isolates of Central American countries. These isolates from Guatemala and Honduras were grouped together with SPCSV-WA isolates from Argentina, United States, Spain, Israel, Nigeria and Egypt. Additionally, the RNase3 gene with UTR at 3´ end of genomic RNA1 gene of SPCSV was sequenced (1264 nt) and aligned against other WA isolates. It was found that the gene for the silencing suppressor protein p22 (676nt) was missing, reflecting intraspecific variation in the genomic structure of SPCSV. These findings revealed the two most important sweetpotato viruses in Guatemala, Honduras, and Central America for the first time and urge further studies of sweetpotato viruses in the region.
  • Jääskeläinen, Anu (Helsingin yliopisto, 2011)
    Pdf-file, link above
  • Ortiz, Fernanda (Helsingin yliopisto, 2009)
    Background. Kidney transplantation (KTX) is considered to be the best treatment of terminal uremia. Despite improvements in short-term graft survival, a considerable number of kidney allografts are lost due to the premature death of patients with a functional kidney and to chronic allograft nephropathy (CAN). Aim. To investigate the risk factors involved in the progression of CAN and to analyze diagnostic methods for this entity. Materials and methods. Altogether, 153 implant and 364 protocol biopsies obtained between June 1996 and April 2008 were analyzed. The biopsies were classified according to Banff ’97 and chronic allograft damage index (CADI). Immunohistochemistry for TGF-β1 was performed in 49 biopsies. Kidney function was evaluated by creatinine and/or cystatin C measurement and by various estimates of glomerular filtration rate (GFR). Demographic data of the donors and recipients were recorded after 2 years’ follow-up. Results. Most of the 3-month biopsies (73%) were nearly normal. The mean CADI score in the 6-month biopsies decreased significantly after 2001. Diastolic hypertension correlated with ΔCADI. Serum creatinine concentration at hospital discharge and glomerulosclerosis were risk factors for ΔCADI. High total and LDL cholesterol, low HDL and hypertension correlated with chronic histological changes. The mean age of the donors increased from 41 -52 years. Older donors were more often women who had died from an underlying disease. The prevalence of delayed graft function increased over the years, while acute rejections (AR) decreased significantly over the years. Sub-clinical AR was observed in 4% and it did not affect long-term allograft function or CADI. Recipients´ drug treatment was modified along the Studies, being mycophenolate mophetil, tacrolimus, statins and blockers of the renine-angiotensin-system more frequently prescribed after 2001. Patients with a higher ΔCADI had lower GFR during follow-up. CADI over 2 was best predicted by creatinine, although with modest sensitivity and specificity. Neither cystatin C nor other estimates of GFR were superior to creatinine for CADI prediction. Cyclosporine A toxicity was seldom seen. Low cyclosporin A concentration after 2 h correlated with TGF- β1 expression in interstitial inflammatory cells, and this predicted worse graft function. Conclusions. The progression of CAN has been affected by two major factors: the donors’ characteristics and the recipients’ hypertension. The increased prevalence of DGF might be a consequence of the acceptance of older donors who had died from an underlying disease. Implant biopsies proved to be of prognostic value, and they are essential for comparison with subsequent biopsies. The progression of histological damage was associated with hypertension and dyslipidemia. The augmented expression of TGF-β1 in inflammatory cells is unclear, but it may be related to low immunosuppression. Serum creatinine is the most suitable tool for monitoring kidney allograft function on every-day basis. However, protocol biopsies at 6 and 12 months predicted late kidney allograft dysfunction and affected the clinical management of the patients. Protocol biopsies are thus a suitable surrogate to be used in clinical trials and for monitoring kidney allografts.
  • Kinnunen, Paula M (Helsingin yliopisto, 2011)
    Several orthopoxviruses (OPV) and Borna disease virus (BDV) are enveloped, zoonotic viruses with a wide geographical distribution. OPV antibodies cross-react, and former smallpox vaccination has therefore protected human populations from another OPV infection, rodent-borne cowpox virus (CPXV). Cowpox in humans and cats usually manifests as a mild, self-limiting dermatitis and constitutional symptoms, but it can be severe and even life-threatening in the immunocompromised. Classical Borna disease is a progressive meningoencephalomyelitis in horses and sheep known in central Europe for centuries. Nowadays the virus or its close relative infects humans and also several other species in central Europe and elsewhere, but the existence of human Borna disease with its suspected neuropsychiatric symptoms is controversial. The epidemiology of BDV is largely unknown, and the present situation is even more intriguing following the recent detection of several-million-year-old, endogenized BDV genes in primate and various other vertebrate genomes. The aims of this study were to elucidate the importance of CPXV and BDV in Finland and in possible host species, and particularly to 1) establish relevant methods for the detection of CPXV and other OPVs as well as BDV in Finland, 2) determine whether CPXV and BDV exist in Finland, 3) discover how common OPV immunity is in different age groups in Finland, 4) characterize possible disease cases and clarify their epidemiological context, 5) establish the hosts and possible reservoir species of these viruses and their geographical distribution in wild rodents, and 6) elucidate the infection kinetics of BDV in the bank vole. An indirect immunofluorescence assay and avidity measurement were established for the detection, timing and verification of OPV or BDV antibodies in thousands of blood samples from humans, horses, ruminants, lynxes, gallinaceous birds, dogs, cats and rodents. The mostly vaccine-derived OPV seroprevalence was found to decrease gradually according to the year of birth of the sampled human subjects from 100% to 10% in those born after 1977. On the other hand, OPV antibodies indicating natural contact with CPXV or other OPVs were commonly found in domestic and wild animals: the horse, cow, lynx, dog, cat and, with a prevalence occasionally even as high as 92%, in wild rodents, including some previously undetected species and new regions. Antibodies to BDV were detected in humans, horses, a dog, cats, and for the first time in wild rodents, such as bank voles (Myodes glareolus). Because of the controversy within the human Borna disease field, extra verification methods were established for BDV antibody findings: recombinant nucleocapsid and phosphoproteins were produced in Escherichia coli and in a baculovirus system, and peptide arrays were additionally applied. With these verification assays, Finnish human, equine, feline and rodent BDV infections were confirmed. Taken together, wide host spectra were evident for both OPV and BDV infections based on the antibody findings, and OPV infections were found to be geographically broadly distributed. PCR amplification methods were utilised for hundreds of blood and tissue samples. The methods included conventional, nested and real-time PCRs with or without the reverse transcription step and detecting four or two genes of OPVs and BDV, respectively. OPV DNA could be amplified from two human patients and three bank voles, whereas no BDV RNA was detected in naturally infected individuals. Based on the phylogenetic analyses, the Finnish OPV sequences were closely related although not identical to a Russian CPXV isolate, and clearly different from other CPXV strains. Moreover, the Finnish sequences only equalled each other, but the short amplicons obtained from German rodents were identical to monkeypox virus, in addition to German CPXV variants. This reflects the close relationship of all OPVs. In summary, RNA of the Finnish BDV variant could not be detected with the available PCR methods, but OPV DNA infrequently could. The OPV species infecting the patients of this study was proven to be CPXV, which is most probably also responsible for the rodent infections. Multiple cell lines and some newborn rodents were utilised in the isolation of CPXV and BDV from patient and wildlife samples. CPXV could be isolated from a child with severe, generalised cowpox. BDV isolation attempts from rodents were unsuccessful in this study. However, in parallel studies, a transient BDV infection of cells inoculated with equine brain material was detected, and BDV antigens discovered in archival animal brains using established immunohistology. Thus, based on several independent methods, both CPXV and BDV (or a closely related agent) were shown to be present in Finland. Bank voles could be productively infected with BDV. This experimental infection did not result in notable pathological findings or symptoms, despite the intense spread of the virus in the central and peripheral nervous system. Infected voles commonly excreted the virus in urine and faeces, which emphasises their possible role as a BDV reservoir. Moreover, BDV RNA was regularly reverse transcribed into DNA in bank voles, which was detected by amplifying DNA by PCR without reverse transcription, and verified with nuclease treatments. This finding indicates that BDV genes could be endogenized during an acute infection. Although further transmission studies are needed, this experimental infection demonstrated that the bank vole can function as a potential BDV reservoir. In summary, multiple methods were established and applied in large panels to detect two zoonoses novel to Finland: cowpox virus and Borna disease virus. Moreover, new information was obtained on their geographical distribution, host spectrum, epidemiology and infection kinetics.
  • Jäämaa, Salla (Helsingfors universitet, 2010)
    Lung transplantation (LTx) is a generally accepted therapy for end-stage lung patients meeting the international criterias. Chronic dysfunction of the allograft, called Brochiolitis Obliterans Syndrome (BOS), is the most important complication limiting the long term survival of these patients. Known risk factors for developing BOS are episodes of acute rejection, CMV-pneumonitis and HLA-immunization. Other risk factors have also been suggested, as one of them gastroesophageal reflux desease (GERD) and the possible microaspiration caused by it. In this study we followed during one year 15 patients who underwent a bilateral LTx in Helsinki University Central Hospital. Our aim was to find out if it is possible to determine bile acids from lung allograft recipients´ bronchoalveolar lavage fluid (BALF) by using a commercially available kit and thus possibly find a useful method to verify the microaspiration in these patients. Our study demonstrates that most patients do have bile acids in their BALF samples during the first year after LTx and that this does not correlate with the reflux symptoms experienced by the patients. We were unable to show correlation between the bile acids in BALF and BOS developed by some patients, but our results indicate that BOS is preceded by repeated episodes of BALF neutrophilia.
  • Katainen, Riku (2013)
    After the Human Genome Project completed the mapping of human DNA sequence in 2001, a new era began in biological and medical research. The genetic basis of various diseases, such as cancer, could be studied with higher precision than ever before. The map of human genome enabled next-generation sequencing (NGS) techniques and not only DNA sequencing got faster and cheaper to perform, also the amount of data started to increase exponentially. The field of bioinformatics, which combines both computer and life sciences, got a great challenge to handle all the data available and to dig out relevant information out of it. Various tools with heavily enhanced or completely new kinds of algorithms were developed for the demanding task of the analysis of NGS data, which are in the focus of this thesis. For the search of cancer causing mutations, NGS methods enable genome scale studies with the precision of a single molecule. However, the spectacular scale and preciseness of the data offer another challenge – how to distinguish trivial data from the non-trivial, and furthermore, how to separate reliable data from erroneous. The raw data must be put through a pipeline of various processing tools, which organize and humanize the data with the help of the map of human genome. After data processing, the data is feasible for the actual cancer specific analysis, where causative mutations can be hunted down. For this purpose, I have developed an analysis and visualization software, Rikurator, which provides various features and tools to handle the NGS data. Rikurator is designed for comparative analysis of dozens of cancer samples, quality filtering, controlling and visualization to name a few. In addition to tools in data processing pipeline, this thesis will describe features and implementation of Rikurator.
  • Lintula, Susanna (Helsingin yliopisto, 2005)
  • Gao, Song (Helsingfors universitet, 2010)
    Molecular biology has created a new pathway for plant breeding in cut flower industry. It focuses on studying flower gene functions and provides a more direct and effective way of breeding new flower cultivars using genetic transformation. Besides flower color, disease resistance, quality and vase life, modification of flower architecture is an important target for flower breeding. Previous studies have showed that various transcription factors encoded by the corresponding genes are involved regulating flower development and flower architecture. The most studied are MADS domain and TCP domain transcription factors. For targeted breeding, it is crucial to study the functions of the corresponding genes in detail. For both MADS and TCP domain proteins, previous studies have indicated that protein-protein interactions are important for their function. GhCYC1, GhCYC2, GhCYC3 and GhCYC4, isolated from gerbera (Gerbera hybrida), are CYCLOIDEA –like genes affecting inflorescence development. The protein-protein interactions among these four genes have previously been studied by yeast two-hybrid system. The aim of this thesis was to verify the interactions in living plant cells, using both BiFC and split luciferase assays. Protoplast electroporation and agroinfiltration were used to introduce the genes in planta. The results from the two assays were compared in order to find an effective in planta method for detecting protein-protein interactions. The experiment also provided information about DNA transformation efficiency using protoplast electroporation and agroinfiltration. The results of the split luciferase assay showed that GhCYC1+GhCYC4, GhCYC3+GhCYC4 as well as GhCYC4+GhCYC4 interacted quite strongly in plant cells while GhCYC1+GhCYC1, GhCYC2+GhCYC2 as well as GhCYC4+GhCYC2 had almost no interactions. The interactions between GhCYC3+GhCYC4, and GhCYC4+ GhCYC4 were also shown in yeast two-hybrid, but the other results were different. According to the BiFC assay, no signals of interactions were detected from GhCYC2+GhCYC2, while strong signals were observed from GhCYC2+GhCYC3, and weak signals were seen from GhCYC2+GhCYC4. The interactions between GhCYC2+GhCYC3, GhCYC2+GhCYC4 were also observed in yeast two-hybrid, but the other results were unconfirmed. Large standard deviations were observed in the split luciferase assay and thereby reliable conclusions cannot be drawn from it. However, BiFC turned out to be a better method to detect the protein-protein interactions in planta and clear signals from interactions could be observed. Comparison of the transformation methods indicated that agroinfiltration is a better way of introducing DNA into plant cells than protoplast electroporation. For further study, BiFC assay still needs to be repeated to confirm the efficiency of this assay, and factors affecting the transformation efficiency in protoplast electroporation need to be optimized in the future studies.
  • Laisalmi, Merja (Helsingin yliopisto, 2006)
    Drugs and surgical techniques may have harmful renal effects during the perioperative period. Traditional biomarkers are often insensitive to minor renal changes, but novel biomarkers may more accurately detect disturbances in glomerular and tubular function and integrity. The purpose of this study was first, to evaluate the renal effects of ketorolac and clonidine during inhalation anesthesia with sevoflurane and isoflurane, and secondly, to evaluate the effect of tobacco smoking on the production of inorganic fluoride (F-) following enflurane and sevoflurane anesthesia as well as to determine the effect of F- on renal function and cellular integrity in surgical patients. A total of 143 patients undergoing either conventional (n = 75) or endoscopic (n = 68) inpatient surgery were enrolled in four studies. The ketorolac and clonidine studies were prospective, randomized, placebo controlled and double-blinded, while the cigarette smoking studies were prospective cohort studies with two parallel groups. As a sign of proximal tubular deterioration, a similar transient increase in urine N-acetyl-beta-D-glucosaminidase/creatinine (U-NAG/crea) was noted in both the ketorolac group and in the controls (baseline vs. at two hours of anesthesia, p = 0.015) with a 3.3 minimum alveolar concentration hour sevoflurane anesthesia. Uncorrelated U-NAG increased above the maximum concentration measured from healthy volunteers (6.1 units/l) in 5/15 patients with ketorolac and in none of the controls (p = 0.042). As a sign of proximal tubular deterioration, U-glutathione transferase-alpha/crea (U-GST-alpha/crea) increased in both groups at two hours after anesthesia but a more significant increase was noted in the patients with ketorolac. U-GST-alpha/crea increased above the maximum ratio measured from healthy volunteers in 7/15 patients with ketorolac and in 3/15 controls. Clonidine diminished the activation of the renin-angiotensin aldosterone system during pneumoperitoneum; urine output was better preserved in the patients treated with clonidine (1/15 patients developed oliguria) than in the controls (8/15 developed oliguria (p=0.005)). Most patients with pneumoperitoneum and isoflurane anesthesia developed a transient proximal tubular deterioration, as U-NAG increased above 6.1 units/L in 11/15 patients with clonidine and in 7/15 controls. In the patients receiving clonidine treatment, the median of U-NAG/crea was higher than in the controls at 60 minutes of pneumoperitoneum (p = 0.01), suggesting that clonidine seems to worsen proximal tubular deterioration. Smoking induced the metabolism of enflurane, but the renal function remained intact in both the smokers and the non-smokers with enflurane anesthesia. On the contrary, smoking did not induce sevoflurane metabolism, but glomerular function decreased in 4/25 non-smokers and in 7/25 smokers with sevoflurane anesthesia. All five patients with S-F- ≥ 40 micromol/L, but only 6/45 with S-F- less than 40 micromol/L (p = 0.001), developed a S-tumor associated trypsin inhibitor concentration above 3 nmol/L as a sign of glomerular dysfunction. As a sign of proximal tubulus deterioration, U-beta 2-microglobulin increased in 2/5 patients with S-F- over 40 micromol/L compared to 2/45 patients with the highest S-F- less than 40 micromol/L (p = 0.005). To conclude, sevoflurane anesthesia may cause a transient proximal tubular deterioration which may be worsened by a co-administration of ketorolac. Clonidine premedication prevents the activation of the renin-angiotensin aldosterone system and preserves normal urine output, but may be harmful for proximal tubules during pneumoperitoneum. Smoking induces the metabolism of enflurane but not that of sevoflurane. Serum F- of 40 micromol/L or higher may induce glomerular dysfunction and proximal tubulus deterioration in patients with sevoflurane anesthesia. The novel renal biomarkers warrant further studies in order to establish reference values for surgical patients having inhalation anesthesia.