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  • Raatikka, Vilho (Helsingin yliopisto, 2004)
  • Laitinen, Leena (Helsingin yliopisto, 2006)
    Several different in vitro absorption models are used in the screening of new drug candidates. One of them is the Caco-2 model, a widely used in vitro model for small intestinal absorption. Caco-2 cells, which originate from a colon carcinoma, differentiate spontaneously to cells that resemble mature small intestinal enterocytes and express carrier proteins similar to the small intestine, and can therefore be used for the assessment of active transport processes during intestinal absorption. Due to variation in cell line differentiation and selection of sub populations, permeability data obtained from different laboratories is seldom directly comparable. Hence, the use of several drugs or compounds with known permeability characteristics are recommended for model standardisation and the use of internal standards in every experiment could offer a solution to the problem. In this study, the simultaneous use of five to ten drugs as internal standards was evaluated. Drugs with different permeability characteristics (high and low permeability, passive and active transport and active efflux) were used to detect their possible effects on cell viability, monolayer integrity and possible interactions during permeability across Caco-2 cell monolayers. After validation of the use of several drugs simultaneously as internal standards, the usefulness of the method was further probed by testing the possible interactions during absorption between drugs and plant extracts that are used as food supplements, functional foods, or natural laxatives. These extracts contain several active compounds, such as flavonoids, alkyl gallates, or anthraquinones, which are able to partition into the cell membranes and thus affect e.g. the fluidity of the membranes, or diffuse across the cell monolayers, either by using active transport mechanisms or passively. Five to ten drugs in one experiment at individual 50 µM concentrations did not cause problems in cell viability (MTT test) or monolayer integrity (transepithelial electrical resistance (TEER) measurements, and 14C-mannitol diffusion test). The individual permeability values in the cocktails correlated closely with those obtained from single-drug experiments, except when active transport of drugs was involved. Drugs with passive permeability can be included in cocktails; no interactions between them are expected. Drugs, which occupy same binding sites of a transport protein, cannot be included as internal standards. According to the results, standard testing of Caco-2 functionality does not require the use of more than 3-4 compounds with very low, low, moderate and high permeability (including substrates for transporters), depending on the characteristics of the studied drug candidates. To probe the effects of plant extracts on the permeability of co-administered drugs, standard drugs with known absorption behaviour can be used. Flax seed extract, for example, decreased the permeability of all co-administered drugs. When flax seeds are used as a laxative, fluids with dissolved drugs are adsorbed on the fibers of flax seed, leading to decreased drug absorption. The effects of other plant extracts, which contain high concentrations of different flavonoids and alkyl gallates, are difficult to predict, because their interactions may be mediated via several active transport proteins, such as OCT, MDR1 and different MRP´s, or additionally via the effects on the cell membrane fluidity, as the permeability experiments with different flavonoids and alkyl gallates proved. Whereas several food-drug interactions have often been attributed to the inhibition of drug metabolizing enzymes, information regarding the effects of food components on transporters during absorption, distribution and excretion of drugs is still limited. Caco-2 cell monolayers, when expressing active transport and efflux proteins, are therefore very well suitable as in vitro model for this type of studies.
  • Tikka, Saara (Helsingin yliopisto, 2009)
    Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is the most common hereditary vascular dementia. CADASIL is a systemic disease of small and medium-sized arteries although the symptoms are almost exclusively neurological, including migraineous headache, recurrent ischemic episodes, cognitive impairment and, finally, subcortical dementia. CADASIL is caused by over 170 different mutations in the NOTCH3 gene, which encodes a receptor expressed in adults predominantly in the vascular smooth muscle cells. The function of NOTCH3 is not crucial for embryonic development but is needed after birth. NOTCH3 directs postnatal arterial maturation and helps to maintain arterial integrity. It is involved in regulation of vascular tone and in the wound healing of a vascular injury. In addition, NOTCH3 promotes cell survival by inducing expression of anti-apoptotic proteins. NOTCH3 is a membrane-spanning protein with a large extracellular domain (N3ECD) containing 34 epidermal growth factor-like (EGF) repeats and a smaller intracellular domain with six ankyrin repeats. All CADASIL mutations are located in the EGF repeats and the majority of the mutations cause gain or loss of one cysteine residue in one of these repeats leading to an odd number of cysteine residues, which in turn leads to misfolding of N3ECD. This misfolding most likely alters the maturation, targetting, degradation and/or function of the NOTCH3 receptor. CADASIL mutations do not seem to affect the canonical NOTCH3 signalling pathway. The main pathological findings are the accumulation of the NOTCH3 extracellular domain on degenerating vascular smooth muscle cells (VSMCs), accumulation of granular osmiophilic material (GOM) in the close vicinity of VSMCs as well as fibrosis and thickening of arterial walls. Narrowing of the arterial lumen and local thrombosis cause insufficient blood flow, mainly in small arteries of the cerebral white matter, resulting in tissue damage and lacunar infarcts. CADASIL is suspected in patients with a suggestive family history and clinical picture as well as characteristic white matter alterations in magnetic resonance imaging. A definitive verification of the diagnosis can be achieved by identifying a pathogenic mutation in the NOTCH3 gene or through the detection of GOM by electron microscopy. To understand the pathology underlying CADASIL, we have generated a unique set of cultured vascular smooth muscle cell (VSMC) lines from umbilical cord, placental, systemic and cerebral arteries of CADASIL patients and controls. Analyses of these VSMCs suggest that mutated NOTCH3 is misfolded, thus causing endoplasmic reticulum stress, activation of the unfolded protein response and increased production of reactive oxygen species. In addition, mutation in NOTCH3 causes alterations in actin cytoskeletal structures and protein expression, increased branching and abnormal node formation. These changes correlate with NOTCH3 expression levels within different VSMCs lines, suggesting that the phenotypic differences of SMCs may affect the vulnerability of the VSMCs and, therefore, the pathogenic impact of mutated NOTCH3 appears to vary in the arteries of different locations. Furthermore, we identified PDGFR- as an immediate downstream target gene of NOTCH3 signalling. Activation of NOTCH induces up-regulation of the PDGFR- expression in control VSMCs, whereas this up-regulation is impaired in CADASIL VSMCs and might thus serve as an alternative molecular mechanism that contributes to CADASIL pathology. In addition, we have established the congruence between NOTCH3 mutations and electron microscopic detection of GOM with a view to constructing a strategy for CADASIL diagnostics. In cases where the genetic analysis is not available or the mutation is difficult to identify, a skin biopsy is an easy-to-perform and highly reliable diagnostic method. Importantly, it is invaluable in setting guidelines concerning how far one should proceed with the genetic analyses.
  • Louhivuori, Lauri (Helsingin yliopisto, 2015)
    Signaling pathways linked to changes in the intracellular cytosolic concentrations of free calcium are involved in a plethora of cellular activities ranging from cell division, differentiation and migration, integration of neural circuits, as well as programmed neuronal cell death. Channels that permit the entrance of calcium into neuronal cells have gathered considerable interest due to their potential of being significant therapeutic targets not least to mention a means by which to answer key neurophysiological questions. This thesis investigates two distinct calcium influx pathways: one mediated by the transient receptor potential channel family which can be either directly activated or indirectly via second messengers and the second pathway involving voltage gated calcium channels. Using a neuronal cell line model (human neuroblastoma IMR-32) as well as the neural progenitor stem cell neurosphere assay with molecular biology techniques, immunocytochemistry, calcium imaging, electrophysiology and time-lapsed imaging the thesis culminates to provide novel insights into the interplay between these channel proteins and the differentiation and migration of neuronal cells. Furthermore it provides new information on the molecular mechanisms involved in the interaction between developing neurons and radial glial cells, whereby the migrational behavior of neuronal cells is influenced by the calcium influx pathways mediated by glutamate receptors in radial glial cells.
  • Ng, Kim (2012)
    In analysis of structural information for transmembrane (TM) proteins it is ideal to work with a three-dimensional (3D) structure. This is not always possible as determining an accurate 3D structure can be challenging and expensive as pursuing one can take large amounts of time. Sequence analysis is often used as a surrogate to determine a subset of information regarding secondary and tertiary protein structure given the primary structure (an amino acid sequence). Using Equilibrative Nucleoside Transporter member 1 (ENT1) as a model, the objective of predicting secondary and tertiary structure given primary structure is attempted through computational (in silico) methods. The in silico methods include the use of a pipeline of programs spanning both custom made and ready built software. A set of 2034 homologous protein sequences are first obtained from the initial human ENT1 (hENT1) sequence through a BLASTp. This sequence information is then processed to acquire information on variation, conservation, and hydrophobicity through topology prediction, hydropathic moment plots and variation moment plots. Comparing these results with data acquired from Glycerol-3-Phosphate Transporter (GlpT), a protein with a known 3D structure of 3.3 Angstrom resolution is done to assess evidence of evolutionary origin. This in turn allows estimation on the reliability of predictions to be made on aspects of the secondary and tertiary structure for hENT1. The results show that within predicted TM alpha helical regions that there is some level of correlation between the variation of the amino acids within the alpha helical TM region and its orientation towards the membrane. This can be further refined by gathering statistics on other known proteins with a 3D structure for their relationships in TM regions to hydrophobicity and variability. This will aid in secondary and tertiary structure predictions of other TM proteins given further refinement and additional data. In addition, the sequence conservation information obtained should prove to be robust and allow for a large number of sequences to be analyzed to determine conservation of amino acids given a reference protein. Ideally this information will provide aid in determining interesting amino acids for experiments to be done on hENT1.
  • Tamminen, Sakari (Faculty of Social Sciences, University of Helsinki, 2010)
    In recent decades, nation-states have become major stakeholders in nonhuman genetic resource networks as a result of several international treaties. The most important of these is the juridically binding international Convention on Biological Diversity (CBD), signed at the Rio Earth Summit in 1992 by some 150 nations. This convention was a watershed for the identification of global rights related to genetic resources in recognising the sovereign power of signatory nations over their natural resources. The contracting parties are legally obliged to identify their native genetic material and to take legislative, administrative, and/or policy measures to foster research on genetic resources. In this process of global bioprospecting in the name of biodiversity conservation, the world's nonhuman genetic material is to be indexed according to nation and nationality. This globally legitimated process of native genetic identification inscribes national identity into nature and flesh. As a consequence, this new form of potential national biowealth forms also what could be called novel nonhuman genetic nationhoods. These national corporealities are produced in tactical and strategic encounters of the political and the scientific, in new spaces crafted through technical and institutional innovation, and between the national reconfiguration of the natural and cultural as framed by international political agreements. This work follows the creation of national genetic resources in one of the biodiversity-poor countries of the North, Finland. The thesis is an ethnographic work addressing the calculation of life: practices of identifying, evaluating, and collecting nonhuman life in national genetic programmes. The core of the thesis is about observations made within the Finnish Genetic Resources Programmes in 2004 2008, gathered via multi-sited ethnography and related methods derived from the anthropology of science. The thesis explores the problematic relations of the communal forms of human and nonhuman life in an increasingly technoscientific contemporaneity  the co-production and coexistence of human and nonhuman life in biopolitical formations called nations.
  • Keskinen, Matti (2012)
    Tässä tutkelmassa esitellään algebrallisen ryhmän käsite sekä hieman tavallisesta poikkeava tapa ymmärtää permutaatioita. Työn tärkeimpinä kohtina voi pitää Caleyn lausetta, joka yhdistää permutaation ja ryhmän käsitteet, sekä p-ryhmän käsitettä. Työssä käsitellään myös pintapuolisesti suoraan tuloon liittyviä ryhmiä. Varsinaisia esitietovaatimuksia työn ymmärtämiseksi ei ole, mutta tietynlainen matemaattinen yleissivisistys on toivottavaa. Kenen tahansa kandidaattitasoisen matematiikan opiskelijan kuitenkin pit äisi pystyä ymmärtämään tämän tutkielman oleellinen sisältö. Esitelmäni perustuu Joseph J. Rotmanin kirjaan An Introduction to the Theory of Groups [2]. Tukena olen käyttänyt Tauno Metsänkylän ja Marjatta Näätäsen teosta Algebra I [1]. Permutaatioita käsittelevässä luvussa olen tukeutunut Pekka Tuomisen Todennäköisyyslaskenta I- kirjaan [3]. Permutaatioita oli tutkittu jo aikaisemminkin, mutta ryhmien teorian tutkimuksen aloitti varsinaisesti Galois (1811-1832). 1800-luvun lopussa ryhmäteoriaa tutkittiin lähinnä kahdessa päähaarassa. Nämä päähaarat olivat algebralliset ryhmät, erityisesti Lien ryhmät, sekä äärelliset ryhmät. 1900-luvulla ilmaantui kuitenkin kolmas päähaara, äärettömät ryhmät. Nykyään ryhmät esiintyvät monilla matematiikan aloilla, esimerkiksi geometriassa, topologiassa ja logiikassa.
  • Hakala, Jani (2012)
    The most important parameters describing the aerosol particle population are the size, concentration and composition of the aerosol particles. The size and water content of the aerosol particles are dependent of the relative humidity of the ambient air. Hygroscopicity is a measure to describe the water absorption ability of an aerosol particle. Volatility of an aerosol defines how the aerosol particles behave as a function of temperature. A Volatility-Hygroscopicity Tandem Differential Mobility Analyzer (VH-TDMA) is an instrument for size-selected investigation of particle number concentration, volatility, hygroscopicity and the hygroscopicity of the particle core, i.e. what is left of the particle after the volatilization. While knowing these qualities of aerosol particles, one can predict their behavior in different atmospheric conditions. Volatility and hygroscopicity can also be used for indirect analysis of chemical composition. The aim of this study was to build and characterize a VH-TDMA, and report the results of its field deployment at the California Nexus (CalNex) 2010 measurement campaign. The calibration measurements validated that with the VH-TDMA one can obtain accurate volatility and hygroscopicity measurements for particles between 20 nm and 145 nm. The CalNex 2010 results showed that the instrument is capable in field measurements at varying measurement conditions; and valuable data about hygroscopicty, volatility and the mixing state of several types of aerosols were measured. The data obtained was in line with the observations based on the data measured with other instruments.
  • Varho, Vilja (Helsingin yliopisto, 2007)
    Wind power has grown fast internationally. It can reduce the environmental impact of energy production and increase energy security. Finland has turbine industry but wind electricity production has been slow, and nationally set capacity targets have not been met. I explored social factors that have affected the slow development of wind power in Finland by studying the perceptions of Finnish national level wind power actors. By that I refer to people who affect the development of wind power sector, such as officials, politicians, and representatives of wind industries and various organisations. The material consisted of interviews, a questionnaire, and written sources. The perceptions of wind power, its future, and methods to promote it were divided. They were studied through discourse analysis, content analysis, and scenario construction. Definition struggles affect views of the significance and potential of wind power in Finland, and also affect investments in wind power and wind power policy choices. Views of the future were demonstrated through scenarios. The views included scenarios of fast growth, but in the most pessimistic views, wind power was not thought to be competitive without support measures even in 2025, and the wind power capacity was correspondingly low. In such a scenario, policy tool choices were expected to remain similar to ones in use at the time of the interviews. So far, the development in Finland has followed closely this pessimistic scenario. Despite the scepticism about wind electricity production, wind turbine industry was seen as a credible industry. For many wind power actors as well as for the Finnish wind power policy, the turbine industry is a significant motive to promote wind power. Domestic electricity production and the export turbine industry are linked in discourse through so-called home market argumentation. Finnish policy tools have included subsidies, research and development funding, and information policies. The criteria used to evaluate policy measures were both process-oriented and value-based. Feed-in tariffs and green certificates that are common elsewhere have not been taken to use in Finland. Some interviewees considered such tools unsuitable for free electricity markets and for the Finnish policy style, dictatorial, and being against western values. Other interviewees supported their use because of their effectiveness. The current Finnish policy tools are not sufficiently effective to increase wind power production significantly. Marginalisation of wind power in discourses, pessimistic views of the future, and the view that the small consumer demand for wind electricity represents the political views of citizens towards promoting wind power, make it more difficult to take stronger policy measures to use. Wind power has not yet significantly contributed to the ecological modernisation of the energy sector in Finland, but the situation may change as the need to reduce emissions from energy production continues.
  • Schönberg-Norio, Daniela (Helsingin yliopisto, 2009)
    Campylobacter jejuni and C. coli are the leading causes of human bacterial gastroenteritis in developed countries. Most human Campylobacter infections are sporadic and a seasonal peak in the distribution of infections can be seen in the summer months in several countries, including Finland. A variety of risk factors for Campylobacter infections have been identified; handling and eating poultry, drinking unpasteurized milk, contact with domestic animals, and travelling abroad. However, the relative importance of the different risk factors in sporadic cases of Campylobacter infection remains unknown. In most cases, the infection is self-limiting and no specific treatment is required. Campylobacter enteritis can cause a wide range of complications, including reactive arthritis (ReA) that is reported in 1-5% of the cases. Seven clinical microbiology laboratories serving different geographical areas of Finland, participated in this multi-centre study, conducted during a seasonal peak in 2002. In a matched case-control study, domestically-acquired sporadic Campylobacter infections from three geographical areas were collected. The final study comprised 100 cases and 137 controls. Risk factors for sporadic domestically-acquired Campylobacter infections were identified on the basis of a questionnaire; swimming in natural waters was found to be a novel risk factor for Campylobacter infection. Other independent risk factors were tasting or eating raw or undercooked meat and drinking untreated water from a dug well. The role of bacterial strain and host characteristics are not fully understood in Campylobacter infections. Exposure factors, demographical characteristics, and the serotype of the Campylobacter isolate may affect the severity of the enteritis. This cross-sectional study comprised 114 patients with C. jejuni enteritis, diagnosed in three clinical microbiology laboratories; most of the patients had participated in the previous case-control study. Swimming was associated with age ≤ 5 years and serotype Pen 6,7 was found significantly more often among patients reporting swimming. The geographical distribution among serotypes varied; serotype Pen 4-complex appeared more often in patients from urban areas and serotype Pen 21 among patients from more rural areas. Thus, risk factors and sources of infection for C. jejuni infection may vary among individuals depending on age and geographical location. The in vitro susceptibilities of C. jejuni and C. coli strains isolated from patients infected abroad (85 strains) or domestically (393 strains) revealed that susceptibility to erythromycin is still high, even among isolates of foreign origin. However, the novel antimicrobial agent telithromycin did not offer any advantage over erythromycin; isolates with high minimal inhibitory concentrations (MICs) for erythromycin also showed reduced susceptibility to telithromycin. Reduced susceptibility to fluoroquinolones was detected almost exclusively among isolates of foreign origin and half of these isolates with high MICs for fluoroquinolones also showed elevated MICs for doxycycline. Questionnaires concerning complications associated with C. jejuni enteritis were sent to patients two months after becoming ill; 201 patients from seven different geographical areas were included in the study. Musculoskeletal complications after C. jejuni infection were commonly reported by patients (39%). The incidence of classical ReA was 4% and that of Achilles enthesopathy and/or heel pain 9%. Other C. jejuni-associated reactive joint symptoms were commonly reported, however, due to their milder nature seldom seen and diagnosed by a physician. The severity of the enteritis may predict further complications; stomach ache during enteritis was connected to the development of later joint pain. Early antimicrobial treatment, within two days from the start of symptoms, shortened the duration of diarrhoea by two days but did not prevent later musculoskeletal complications. Campylobacter is an important human enteropathogen and causes a significant burden of illness. As the incidence of Campylobacter infections is high, the importance of the infection and the occurrence of complications will increase. This stresses the importance of understanding the risk factors for acquiring Campylobacter infection and how bacterial strain and host characteristics may affect the risk for infection. The role of antimicrobial treatment for acute Campylobacter enteritis seems to be marginal and should be used restrictively.
  • Perko-Mäkelä, Päivikki (Helsingin yliopisto, 2011)
    Campylobacter, mainly Campylobacter jejuni and C. coli, are worldwide recognized as a major cause of bacterial food-borne gastroenteritis. Epidemiological studies have shown handling or eating of poultry to be significant risk factors for human infections. Campylobacter contamination can occur at all stages of a poultry meat production cycle. The aim of this thesis was to study the occurrence and diversity of Campylobacter in broiler and turkey production in Finland. In summer 1999, 2.9 % of slaughtered broiler flocks were Campylobacter-positive. From the isolated strains 94 % were C. jejuni and 6% were C. coli. During years 2005-2006 one turkey parent flock, the hatchery, six different commercial turkey farms and different stages of the slaughterhouse were monitored during one and the half year. No Campylobacter were detected in either of the samples from the turkey parent flock or from the hatchery using the culture method. Instead PCR detected DNA of Campylobacter from the turkey parent flock and samples from the hatchery. Six out of 12 commercial turkey flocks were found negative at the farm level but only two of those were negative at slaughter. Campylobacter-positive samples within the flock at slaughter were detected between 0% and 94% with evisceration and chilling water being the most critical stages for contamination. All of Campylobacter isolates were shown to be C. jejuni. Campylobacter-positive turkey flocks were colonized by a limited number of Campylobacter genotypes both at the farm and slaughter level. In conclusion, in our first study in 1999 a low prevalence of Campylobacter in Finnish broiler flocks was detected and it has remained at a low level during the study period until the present. In the turkey meat production, we found that flocks which were negative at the farm became contaminated with Campylobacter at the slaughter process. These results suggest that proper and efficient cleaning and disinfection of slaughter and processing premises are needed to avoid cross-contamination. Prevention of colonization at the farm by a high level of biosecurity control and hygiene may be one of the most efficient ways to reduce the amount of Campylobacter-positive poultry meat in Finland. With a persistent low level of Campylobacter-positive flocks, it could be speculated that the use of logistic slaughtering, according to Campylobacter status at farm, might have be advantageous in reducing Campylobacter contamination of retail poultry products. However, the significance of the domestic poultry meat for human campylobacteriosis in Finland should be evaluated.
  • Lilja, Liisa (2001)
    Kampylobakteerit ovat teollisuusmaissa tavallisimpia diagnosoituja bakteeriperäisen gastroenteriitin aiheuttajia. C. jejuni aiheuttaa noin 90-95 % infektioista ja C. coli tavallisesti 5-10 %. Suomessa sairastuu vuosittain noin 3000 henkilöä kampylobakterioosiin. Infektioiden määrä on vähäinen talvella ja keväällä, jolloin suurin osa tapauksista on ulkomaista alkuperää. Kesäkuukausien aikana kampylobakteeri-infektioiden määrä kasvaa ja tapauksista jopa puolet voi olla kotimaista alkuperää. Yleensä tapaukset ovat yksittäisiä ja epidemioita esiintyy harvoin. Tartuntalähteistä tärkeimpinä pidetään saastunutta juomavettä ja broilerinlihaa. Perinteiset kampylobakteerien tunnistamismenetelmät ruokanäytteistä ovat aikaa vieviä ja hankalia. Ne sisältävät näytteen esirikastuksen, viljelyn selektiivisille alustoille sekä biokemiallisen varmistuksen. Viime vuosina kampylobakteerien tunnistamiseen tarkoitetut nopeat menetelmät, kuten nukleiinihappohybridisaatio, PCR (polymerase chain reaction) ja ELISA (enzyme-linked immuno-sorbent assay) ovat kehittyneet. Näiden pikamenetelmien kehitys avaa uusia mahdollisuuksia mm. teollisuudelle elintarvikevalvontaan. Opinnäytetyössä verrataan EiaFoss-ELISA-kampylobakteerimenetelmää, viljelymenetelmää ja PCR-analyysia C. jejunin ja C. colin toteamiseen ja tunnistamiseen broilertuotteista. EiaFoss-ELISA-menetelmä on kvalitatiivinen määritysmenetelmä C. jejunin ja C. colin tunnistamiseen elintarvikkeista (rikastus 46 h + täysin automatisoitu analyysi 2 h). ELISA-analyysi perustuu ”sandwich”-tekniikkaan, jossa kaksi erilaista polyklonaalista vasta-ainetta ovat kampylobakteeriantigeeneja vastaan. Viljelymenetelmä sisältää näytteen rikastuksen, viljelyn CCDA-maljalle (valikoiva kampylobakteerialusta ilman verta), maljojen inkuboinnin mikroaerofiilisissä olosuhteissa, tyypillisten pesäkkeiden jatkoviljelyn ja biokemiallisen varmistuksen. Valittu PCR-menetelmä sisältää rikasteliemen esikäsittelyn BDC (Buoyant Density Sentrifugation) menetelmällä, joka erottelee ominaispainoon perustuen bakteerit ja PCR-inhibittorit rikasteliemestä ja konsentroi bakteerit, sekä C. jejuni spesifisen PCR-analyysin. Tutkimuksessa analysoitiin yhteensä 105 tuotetta, joista 60 siipikarjatuotetta oli valittu juuri menetelmien vertailuun. Vaihtelut kaikkien kolmen menetelmän tuloksissa olivat vähäisiä. EiaFoss-positiivisia oli 13, PCR-positiivisia 10 ja viljely-positiivisia näytteitä 10. Varmaksi positiiviseksi tulokseksi määriteltiin sellainen näyte, joka antoi kahdella tai kaikilla kolmella menetelmällä positiivisen tuloksen. Näin ollen varmojen positiivisten määrä oli 12, joista 11 kyseessä oli C. jejuni ja yhdessä C. coli. Sekä EiaFoss- että BDC-PCR-menetelmissä väärien negatiivisten tulosten osuus oli 1,7 % näytteistä. Viljelymenetelmän väärät negatiiviset (3,3 %) johtuivat todennäköisesti valitusta pitkästä rikastusajasta, eivätkä siksi anna täysin oikeaa kuvaa kampylobakteereiden tunnistamisesta viljelemällä. EiaFoss-menetelmällä esiintyi vääriä positiivisia tuloksia (viljely- ja PCR-negatiivisia) 3,3 %. Viljely- ja BDC-PCR-menetelmissä ei esiintynyt vääriä positiivisia. Tämän perusteella sekä EiaFoss- että BDC-PCR-menetelmät osoittautuivat helpoiksi ja luotettaviksi pikamenetelmiksi tunnistaa kampylobakteerit broilernäytteistä.
  • Kalliala, Ilkka (Helsingin yliopisto, 2010)
    Cervical cancer develops through precursor lesions, i.e. cervical intraepithelialneoplasms (CIN). These can be detected and treated before progression to invasive cancer. The major risk factor for developing cervical cancer or CIN is persistent or recurrent infection with high-risk human papilloma virus (hrHPV). Other associated risk factors include low socioeconomic status, smoking, sexually transmitted infections, and high number of sexual partners, and these risk factors can predispose to some other cancers, excess mortality, and reproductive health complications as well. The aim was to study long-term cancer incidence, mortality, and reproductive health outcomes among women treated for CIN. Based on the results, we could evaluate the efficacy and safety of CIN treatment practices and estimate the role of the risk factors of CIN patients for cancer incidence, mortality, and reproductive health. We collected a cohort of 7 599 women treated for CIN at Helsinki University Central Hospital from 1974 to 2001. Information about their cancer incidence, cause of death, birth of children and other reproductive endpoints, and socio-economic status were gathered through registerlinkages to the Finnish Cancer Registry, Finnish Population Registry, and Statistics Finland. Depending on the endpoints in question, the women treated were compared to the general population, to themselves, or to an age- and municipality-matched reference cohort. Cervical cancer incidence was increased after treatment of CIN for at least 20 years, regardless of the grade of histology at treatment. Compared to all of the colposcopically guided methods, cold knife conization (CKC) was the least effective method of treatment in terms of later CIN 3 or cervical cancer incidence. In addition to cervical cancer, incidence of other HPV-related anogenital cancers was increased among those treated, as was the incidence of lung cancer and other smoking-related cancers. Mortality from cervical cancer among the women treated was not statistically significantly elevated, and after adjustment for socio-economic status, the hazard ratio (HR) was 1.0. In fact, the excess mortality among those treated was mainly due to increased mortality from other cancers, especially from lung cancer. In terms of post-treatment fertility, the CIN treatments seem to be safe: The women had more deliveries, and their incidence of pregnancy was similar before and after treatment. Incidence of extra-uterine pregnancies and induced abortions was elevated among the treated both before and after treatment. Thus this elevation did not occur because they were treated rather to a great extent was due to the other known risk factors these women had in excess, i.e. sexually transmitted infections. The purpose of any cancer preventive activity is to reduce cancer incidence and mortality. In Finland, cervical cancer is a rare disease and death from it even rarer, mostly due to the effective screening program. Despite this, the women treated are at increased risk for cancer; not just for cervical cancer. They must be followed up carefully and for a long period of time; general health education, especially cessation of smoking, is crucial in the management process, as well as interventions towards proper use of birth control such as condoms.
  • Taskila, Taina (Helsingin yliopisto, 2007)
    Due to the improved prognosis of many forms of cancer, an increasing number of cancer survivors are willing to return to work after their treatment. It is generally believed, however, that people with cancer are either unemployed, stay at home, or retire more often than people without cancer. This study investigated the problems that cancer survivors experience on the labour market, as well as the disease-related, sociodemographic and psychosocial factors at work that are associated with the employment and work ability of cancer survivors. The impact of cancer on employment was studied combining the data of Finnish Cancer Registry and census data of the years 1985, 1990, 1995 or 1997 of Statistics Finland. There were two data sets containing 46 312 and 12 542 people with cancer. The results showed that cancer survivors were slightly less often employed than their referents. Two to three years after the diagnosis the employment rate of the cancer survivors was 9% lower than that of their referents (64% vs. 73%), whereas the employment rate was the same before the diagnosis (78%). The employment rate varied greatly according to the cancer type and education. The probability of being employed was greater in the lower than in the higher educational groups. People with cancer were less often employed than people without cancer mainly because of their higher retirement rate (34% vs. 27%). As well as employment, retirement varied by cancer type. The risk of retirement was twofold for people having cancer of the nervous system or people with leukaemia compared to their referents, whereas people with skin cancer, for example, did not have an increased risk of retirement. The aim of the questionnaire study was to investigate whether the work ability of cancer survivors differs from that of people without cancer and whether cancer had impaired their work ability. There were 591 cancer survivors and 757 referents in the data. Even though current work ability of cancer survivors did not differ between the survivors and their referents, 26% of cancer survivors reported that their physical work ability, and 19% that their mental work ability had deteriorated due to cancer. The survivors who had other diseases or had had chemotherapy, most often reported impaired work ability, whereas survivors with a strong commitment to their work organization, or a good social climate at work, reported impairment less frequently. The aim of the other questionnaire study containing 640 people with the history of cancer was to examine extent of social support that cancer survivors needed, and had received from their work community. The cancer survivors had received most support from their co-workers, and they hoped for more support especially from the occupational health care personnel (39% of women and 29% of men). More support was especially needed by men who had lymphoma, had received chemotherapy or had a low education level. The results of this study show that the majority of the survivors are able to return to work. There is, however, a group of cancer survivors who leave work life early, have impaired work ability due to their illness, and suffer from lack of support from their work place and the occupational health services. Treatment-related, as well as sociodemographic factors play an important role in survivors' work-related problems, and presumably their possibilities to continue working.
  • Nieminen, Mikko (2011)
    Yläruoansulatuskanavan syöpien tärkeimpiä riskitekijöitä ovat tupakointi, alkoholin suurkulutus ja huono suuhygienia. Näiden tekijöiden vaikutuksesta sylkeen erittyy korkeita pitoisuuksia asetaldehydiä, jonka Kansainvälinen syöväntutkimuslaitos (IARC) on luokitellut 1-ryhmän karsinogeeniksi. Suuri osa syljen asetaldehydistä on suun mikrobien tuottamaa. Tiedetään, että suun mikrobiomiin kuuluvat bakteerit ja Candida albicans -hiivat kykenevät tuottamaan mutageenisiä määriä asetaldehydiä. C. albicansin aiheuttaman kroonisen mukosiitin onkin todettu olevan karsinogeeninen. Muiden kandidalajien (non- albicans Candida, NAC) määrän on todettu kasvavan etenkin suusyöpähoitoja saavilla potilailla ja toisinaan osalle näistä potilaista kehittyy uusi primäärikarsinooma kandidamukosiitin läheisyyteen. NAC-lajien kykyä tuottaa asetaldehydiä ei kuitenkaan ole aiemmin tutkittu. Tutkimuksen tavoitteena oli selvittää pystyvätkö NAC-lajit tuottamaan karsinogeenisiä määriä asetaldehydiä etanoli- ja glukoosi-inkubaatiossa in vitro. Kaikkiaan kolmenkymmenen (n=30) kliinisen ja kantapankkiNAC-kannan kyky tuottaa asetaldehydiä etanoli- ja glukoosi-inkubaatiossa mitattiin kaasukromatografilla. Yksi C. albicans kantapankkikanta oli mukana kontrollina. Kaikki kandidahiivat tuottivat merkittäviä määriä asetaldehydiä etanoli-inkubaatiossa in vitro. C. tropicalis –kannat tuottivat eniten (252,3 µM) ja C. krusei –kannat vähiten (54,6 µM) asetaldehydiä etanolista. NAC-lajeista ainoastaan C. glabrata tuotti merkittäviä määriä asetaldehydiä glukoosia fermentoimalla. Suuontelon kolonisoituminen merkittävään asetaldehydituotantoon pystyvällä NAC-lajilla kuten C. glabratalla voi altistaa suun limakalvon paikallisesti korkeille määrille asetaldehydiä, mikä voi johtaa suusyövän kehittymiseen.
  • Pärnänen, Pirjo (Helsingin yliopisto, 2010)
    The aim of this thesis was to compare the degradation of human oral epithelial proteins by proteinases of different Candida yeast species. We focused on proteins associated with Candida invasion in the cell-to-cell junction, the basement membrane zone, the extracellular matrix, and local tissue inflammatory regulators. Another main objective was to evaluate the effect of the yeast/hyphal transition and pH on the degradative capability of Candida. The enzymatic activity of the Candida proteinases was verified by gelatin zymography. Laminins-332 (Lm-322) and -511(Lm-511) produced by human oral keratinocytes were gathered from the growth media, and E-cadherin (E-Cad) was isolated from the cell membrane of the keratinocytes by immunoprecipitation. The proteins were incubated with Candida cells and cell-free fractions, and degradation was detected by fluorography. Fibronectin degradation was visualised by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE). Matrix metalloproteinase-9 (MMP-9) activation and tissue inhibitor of metalloproteinase-1 (TIMP-1) fragmentation was detected by using the Western blot and enhanced chemoluminescence (ECL) techniques. Residual activity of TIMP-1 was evaluated by a casein degradation assay. A fluorimetric assay was used to detect and compare Candida proteinase activities with MMP-9. These studies showed that the ability of the different Candida yeast species to degrade human Lm-332, fibronectin, and E-Cad vary from strain to strain and that this degradation is pH-dependent. This indicates that local acidic pH in tissue may play a role in tissue destruction by activating Candida proteinases and aid invasion of Candida into deeper tissue. A potential correlation exists between the morphological form of the yeasts and the degradative ability; the C. albicans yeast form seems to be related to superficial infections, and hyphal forms can apparently invade deeper tissues between the epithelial cells by degradation of E-Cad. Basement membrane degradation is possible, especially in the junctional epithelium, which contains only Lm-332 as a structural component. Local tissue host inflammatory mediators, such as MMP-9, were activated, and TIMP-1 was degraded by certain Candida species, thus indicating the possibility of a weakened host tissue defence mechanism in vivo.
  • Donner, Jonas (Helsingin yliopisto, 2012)
    Anxiety disorders, such as panic disorder (PD), obsessive-compulsive disorder, post-traumatic stress disorder, generalized anxiety disorder, and phobias are common psychiatric disorders, characterized by exaggerated, prolonged and debilitating levels of anxiety. They are complex diseases with onset influenced by both environmental and genetic factors, but so far little progress has been made in identifying solid susceptibility genes. The aim of this study was to shed light on the genetic basis of human anxiety disorders by genetic analyses of putative susceptibility genes. Altogether, 333 single nucleotide polymorphism markers from 30 genes were tested for genetic association to anxiety disorders in a sample (N = 974) derived from the Finnish population-based Health 2000 cohort. Three other samples from Spain (N = 503), Sweden (N = 2020) and USA (N = 1128) were used for replication attempts or meta-analyses. The studied genes were 1) selected based on a mouse model of anxiety-like behavior; 2) an asthma-linked receptor (neuropeptide S receptor 1; NPSR1) and its neuropeptide ligand (neuropeptide S; NPS); and 3) selected based on previous findings in anxiety disorders or anxiety-related personality traits. We also evaluated whether any of the studied genes modulate probability for anxiety disorders in interaction with childhood adverse life events, which are strong environmental risk factors for anxiety disorders. First, with a cross-species approach, we discovered that six of the murine candidate genes associated with specific human anxiety disorders. The implicated genes link novel biological pathways to anxiety susceptibility. Second, NPSR1 and NPS associated with PD in adults, and symptoms of anxiety/depression in children. Our findings suggest that NPS-NPSR1 signaling modulates predisposition not only to asthma, but also to anxiety. Third, of the putative susceptibility genes examined based on previous studies, the strongest associations were for glutamate decarboxylase 1 (GAD1) with phobias. Our results, together with previous findings in the gene, support the role of GAD1 as a risk factor for anxiety- and mood disorders, and neuroticism. Fourth, the neuropeptide Y (NPY) gene modulated the effects of the number of experienced childhood adversities on anxiety susceptibility. NPY may therefore influence individual variation in stress resilience. In conclusion, we identified altogether ten potential susceptibility genes for anxiety disorders. They should be further evaluated in independent study samples, and studied functionally to understand how they may regulate behavior. Such future studies will be essential for evaluating their therapeutic potential in treatment of anxiety disorders. Our findings also support the notion that understanding of the interplay between environmental risk factors and genetic variants is important for understanding predisposition to psychiatric disorders.