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  • Halonen, Kirsi (Helsingin yliopisto, 2013)
    The aim of this study is to describe the expectations and experiences related to the promo-tion of the pedagogical competence of kindergarten teachers in multilingual and multicultural day-care centres, the operations of which have been supported by raising the number of kindergarten teachers from one to two in the care groups. This was enabled by the “positive discrimination funding” offered to those City of Helsinki day-care centres where the number of multilingual and -cultural children exceeds 30%. Three main questions emerged as the research questions. 1. What kind of expectations do kindergarten teachers in a multilingual and multicultural day-care centre have at the begin-ning of the enhancement of their pedagogical competence? 2. What kind of experiences have kindergarten teachers in a multilingual and multicultural day-care centre acquired during the enhancement of their pedagogical competence? 3. What similarities and differences exist between the expectations and experiences of kindergarten teachers with respect to the enhancement of their pedagogical competence? The sub-questions of the two main ques-tions relate to the activities of the care group, collaboration with the work community, cooperation partners and parents, and any other expectations and later experiences. The study is qualitative, and interviews served as the method for collecting information. The informants included six kindergarten teachers working in three day-care centres of city. Theme interviews as a research method were carried out twice for each informant; one in the autumn and one in the spring. Results include such aspects as small-group pedagogy, the pedagogy of play, child observation, activities planning, team-work and cooperation with the other kindergarten teacher working in a Finnish-as-a-second-language setting in the area. In contrast, the development of professional identity and the processing of professional and pedagogical competence are already mentioned as expectations by two kindergarten teachers, but identified as experiences by several of them.
  • Hiekkala, Anna-Riikka (Helsingin yliopisto, 2015)
    This is a qualitative study researching the current state of early childhood education. The purpose of the study was to find out what kinds of things kindergarten teachers are hoping to change regarding the distribution of work between kindergarten teachers and kindergarten´s nursemaids in day-care centers, and how kindergarten teachers wish the director would act regarding these issues. This study was part of the research project “Transition from the education to the profession and staying at work in the kindergarten teacher career” conducted by the teacher training college of the University of Helsinki. The data was collected using an electronic questionnaire and the study involved 490 kindergarten teachers from five counties in the metropolitan Helsinki area. This study focuses specifically on two open questions and total of the answers was 399. The data is analyzed through a content analysis. The theoretical background of the study is focused on the organisation of the distribution of work and leadership in day-care centers. Previous studies have shown that unclarity on the key tasks of the director in the field of early childhood education has affected confusion and excessive liberties in defining both the directors’ and the kindergarten teachers’ work descriptions. (Hujala 2005; Halttunen 2000; Nivala 1999) In addition, previous studies have shown that the growing work distribution trend in the day-care centers where everyone does everything has negatively affected the pedagogical level of staff, and kindergarten teachers have lost their position in the field of early childhood education. (Hujala 1998; Kinos 2008; Onnismaa & Kalliala 2010). The results showed that kindergarten teachers wish for a clearer definition of their tasks. They also hope better organization of work and usage of working time. Kindergarten teachers wish that directors would be involved in the distribution of work in the day-care centers. They also wish that the expertise of different professional groups would be recognized in the process. The results showed that many kindergarten teachers need the director to support the formation of a clear division of labor and its implementation in day-care centers. The results provide information on what issues the kindergarten teachers think should be payed attention to in day-care center leadership, and how they would want to change the distribution of work in day-care centers.
  • Rintakorpi, Kati (Helsingin yliopisto, 2010)
    Early childhood education carries multiple experiences, activities, challenges, disappointments, achievements and encounters. Small children have difficulties to remember, piece together and pass on those experiences and feelings to their teachers or parents. The aim of this study was to examine the contex and organization of early childhood education where documentation raises and develops. Furthermore it was examined what the documentation of small children means in practice and how the teachers understood it. In this study the mixed methods have been used to expose different perspectives about the subject. Also the material was collected using several methods and is a part of two other studies. The quantitative study was made with material which included 892 randomly chosen children and their teachers from 313 daycare units in the metropolitan area of Finland. The material is a part of a Children´s agentive perception uncovered study (2010), which was carried out by the University of Helsinki. The qualitative study was made by using the material of a VKK-Metro development project, which was carried out also in the metropolitan area (2009). The analysis and the conclusions were made by using Reunamo´s theoretical model of agentive perception and Bronfenbrenner´s ecological systems theory. The angle is childcentered, constructivistic and sosioconstructivistic education. In this study a remarkable confrontation was found between the visions and the practices of the early childhood educators. The documentation was not a powerful educational tool for them and the pedagogy was not built up in a sosioconstructive way. After all it was noticeable that when the teachers got more recources and pedagogical support to the documentation of the children, they found more child-centered angel in their practices as early educators. It seemed that the teachers usally work under quite a pressure and should get more resouces to become able to develop the pedagogy. This study is useful for those who are interested in the child-centered way of working and the documentation as a pedagogical tool. It is also a good basis for further studies and for the attempts to regenerate early childhood education.
  • Vesalainen, Anni (Helsingin yliopisto, 2013)
    This study is a part of relatively new field of co-research. Co-research means that adults research with children. The research trend was influenced by the UN rights of the child and childhood paradigm change in such a way, that the child is seen more capable instead of vulnerable. The aim of this research trend is to listen to children's views of his life and in this way to increase understanding between adults and children, as well as to improve the lives of children. Methods used in this research trend have been studied little. One of the most widely used method is children working as data collectors by taking photographs. The purpose of this study was to find out how children take photographs during the AGENTS co-research project. In this way it was tried to get more information about children as a co-researchers and the photographing method. The aim of this study was to find out the nature of photographing and how photographing was built. I hoped that knowing children s ways of doing would help adults understand children better and to act in children's best interests. Data of this study were selected from the finished video and photo material using Progressive refinement of hypotheses method. Video and photo materials were collected in preschool in Tampere together with 19 children using digital cameras, visual narratives and group discussions. Data for this study consisted of parts of group discussions in which children were told how they take photos and the photos and videos related to these discussions. Data was analyzed by using content analysis. As a result of analysis were found three main way of taking photographs. These were play, informal learning and teasing. The category of play divided tree lower categories which were having fun, secret shooting and competing. The category on informal learning divided to experimental shooting and problem solving. Children photographing were intentional and made them feel good. As data collectors children worked in a complete way. As a conclusion can be said that children are capable of working in such ways that increase their wellness. They only need enough of freedom to do so. Also it can be said that taking photographs is a meaningful way to work for children and it increases adults understanding of children. As a tool camera is enough challenging and encourages creativity. Using camera freely make basis to learn photographing and critical photo reading. Children must give space to work in their own way as data collectors in coming co-research projects. Adults also need to allow children to fool around during co-research projects and take care that all children have cameras and the rules of taking photographs are discussed.
  • Leino, Sanna (Helsingin yliopisto, 2009)
    This study examined year seven students´ proactive coping, self-efficacy and social support seeking. Proactive coping was defined as a behaviour where obstacles are seen as a challenge. In proactive coping, individuals set goals, build up resources and regulate their behaviour to achieve the goals. Self-efficacy can be seen as people’s beliefs about their capabilities. Social support seeking was divided into instrumental support seeking and emotional support seeking. According to the theoretical frame of this study self-efficacy and social support seeking were seen as resources to proactive coping (Greenglass 2002). The participants were 445 year seven students (Mo= 13 years) from seven secondary schools. The data was collected in March-May 2008. The survey consisted 37 Likert-scaled items from the Proactive Coping Inventory and from the General Self-Efficacy Scale. The survey consisted of four scales: Proactive Coping, Instrumental Support Seeking, Emotional Support Seeking and General Self-Efficacy. The participants' age, gender and studying in specialist streams were asked as background information. As a result, most of the participants (62 % girls, 38 % boys) reported fairly strong proactive coping: they can see obstacles as a challenge and they set goals and regulate their behaviour to achieve the goals. Most of the participants reported that they seek instrumental and emotional support when having troubles. Girls reported more social support seeking than did boys and the mean difference was statistically significant. Most of the participants had fairly high sense of self-efficacy. However, 4 % of the participants reported that they don’t believe in their capabilities. Some of these participants reported that they neither use proactive coping nor seek informational or emotional support when having troubles. Proactive coping correlated positively with self-efficacy and with social support seeking. In this study self-efficacy and social support seeking explained 47 % of proactive coping. It was discussed that children’s high sense of self-efficacy and social relationships can act as protective factors in transition to secondary school. When supporting children’s self-efficacy and social relationships one also assists children’s proactive coping. Proactive coping can be seen to support children’s personal growth.
  • Nikander, Heini (Helsingin yliopisto, 2014)
    Tutkielma etsii vastauksia kysymyksiin mitä on lapsen vastaanottaminen, mitä on lapsenkaltaisuus ja miten tulla suureksi. Tutkielman lähdeteksteinä käytetään Markuksen, Matteuksen ja Luukkaan evankeliumitekstejä ”Kuka on suurin?” ja ”Jeesus siunaa lapsia” otsikoiden alta. Tutkielma jakautuu kahteen osaan: analyysiin ja synteesiin. Analyysissa lähdetekstejä on tarkasteltu erikseen. Jokaista synoptista evankeliumia on käsitelty kummankin kohdan osalta erikseen. Analyysiosasta nousseista synoptisten evankelistojen yhteisistä aiheista muodostuvat synteesiosan teemat. Teemoja käsitellään yksittäin peilaten niitä ympäristöönsä, josta käsin evankelistat kirjoittivat. Näitä teemoja ovat vastaanottaminen, valtakunta, lastenkaltaisuus ja suureksi tuleminen. Vastaanottaminen liittyy sekä lapsen että valtakunnan vastaanottamiseen. Vastaanottaa verbinä sisältää hyväksymistä, tervetulleeksi toivottamista ja vieraanvaraisuutta. Lasten vastaanottaminen vaatii näitä kolmea. Lapsen vastaanottaminen ei ollut tavallista, sillä lapset kuuluivat alhaiseen sosiaaliluokkaan ja olivat yhteiskunnallisen arvojärjestyksen loppupäässä. Vastaanottamiseen lasten kanssa liittyy kiinteästi (taivasten/Jumalan) valtakunta. Lapsista tehtiin valtakuntaan astujien malleja. Kaikista yhteiskunnan sosiaaliluokan alhaisista juuri lapset valittiin tähän, ”sillä heidän kaltaistensa on (Jumalan) valtakunta.” Lapsilla oli tiettyjä ominaisuuksia, joita arvostettiin valtakunnassa. Näiksi ominaisuuksiksi on lueteltu riippuvuus, luottamus ja nöyryys. Lastenkaltaisilla oli myös mahdollisuus astua valtakuntaan. Lastenkaltaisiksi on evankeliumitutkimuksessa ehdotettu opetuslapsia ja Jeesuksen seuraajia. Jeesus liikkui syntisten ja halveksittujen parissa, mutta heitä ei huolittu valtakunnan malleiksi, vaikka heitä kuvasi riippuvuus. Lastenkaltaiset ymmärsivät valtakunnan luonteen lahjaksi annettuna ilman omia tekoja, ja että saivat nauttia siitä sellaisina kuin olivat. Suureksi tuleminen kuitenkin liittyy lapsiin, lastenkaltaisiin ja erityisesti syntisiin ja halveksittuihin. Nimittäin suureksi tullut on ensin ollut kaikkien palvelija, siis edellä mainittujen ihmisryhmien. Suureksi tulemiseen vaadittiin kunnian ja häpeän kulttuurin ylittämistä, sillä se oli oman kunnian kustannuksella häpeällisemmän ihmisen etusijalle asettamista. Suurin otti vastaan nämä syntiset ja heikot.
  • Lindroos, Auli (2005)
    Tutkielmassa arvioidaan Barnavårdsföreningen i Finland rf. Länsi-Uudellamaalla järjestämää lasten vertaisryhmätoimintaa toimintaan osallistuneiden lasten ja heidän vanhempiensa näkökulmasta.Tutkielmassa selvitetään minkälaisia vaikutuksia vertaisryhmätoimintaan osallistumisella on perheiden ja lasten elämässä ollut ja millä tavalla vaikutukset ovat nähtävissä. Mahdollisimman kattavan arvioinnin aikaansaamiseksi on tutkimusmenetelmiksi valittu kahden eri menetelmän, haastattelujen ja havainnoinnin yhdistäminen. Tutkimusmenetelmät tukivat ja täydensivät selkeästi toisiaan. Lasten haastatteleminen on yhteiskuntatieteellisessä tutkimuksessa suhteellisen uutta ja harvoin käytetty menetelmä. Lapsille suunnattu vertaisryhmätoiminta voidaan nähdä keinona yrittää ennaltaehkäistä lasten ja nuorten psyykkisiä ongelmia. Menetelminä lasten vertaisryhmätoiminnassa käytetään keskusteluja,luovaa toimintaa, leikkejä, draamaa tai toiminnallisia menetelmiä lasten iästä, kehitystasosta, valmiuksista ja tarpeista riippuen. Lasten vertaisryhmätoiminta on menetelmällisesti sosiaalityössä uutta ja liittyy tarpeeseen kehittää uusia työmuotoja sosiaalityöhön. Vanhemmat kokivat, että perheen tilanteesta kertominen lapselle oli vaikeaa ja sen takia se, että lapset vertaistukiryhmässä saivat ulkopuolisilta asiantuntijoilta tietoa perheen ongelmiin liittyvistä asioista, koettiin helpottavaksi. Vanhemmat tuntuivat uskovan, että lapsen iän karttuessa heille on helpompi kertoa oikealla tavalla, niin että lapsi pystyy kertomuksen ymmärtämään ja sisäistämään. Vertaisryhmätoimintaan osallistumisesta koettiin selkeästi olleen hyötyä lapsille. Vanhemmat kuvasivat vertaisryhmätoiminnan hyötyjä hyvin monella tavalla. Hyöty liittyi monen lapsen kohdalla siihen yksinäisyyden tai erilaisuuden tunteeseen, jota vanhemmat tiesivät lapsensa tunteneen. Myös vertaisryhmätoimintaan osallistuneet lapset olivat poikkeuksetta sitä mieltä, että ryhmätoimintaan osallistuminen oli ollut paitsi mukavaa ja hauskaa, myös tukea antavaa ja vahvistavaa. He kokivat helpottavana sen, että heidän kanssaan avoimesti keskusteltiin perheen ongelmista. He toivoivat, että ryhmätoiminta olisi ollut kestoltaan pitempiaikaista. Kiinnittämällä tarkempaa huomiota ryhmien kokoonpanoon ja tiivistämällä yhteistyötä vanhempien kanssa ryhmätoiminnan järjestäjä voi saada toiminnan entistä paremmin vastaamaan perheiden odotuksia. Tutkielmassa käytetyistä lähteistä tärkeimpiä ovat olleet Marianne Nylundin vertaisryhmätoimintaa koskevat teokset ja Annika Taiton ja Rita Jähin kokemukset päihde- ja mielenterveysongelmaisissa perheissä kasvaneiden lasten auttamisesta.
  • Liakka, Anni (Helsingin yliopisto, 2015)
    The focus of this study was on kirgergartners’ mathematical skills and task avoidance. Previous studies have shown that task avoidance is not a stable child characteristics in kindergarten-aged children, but may begin to stabilize during the first school years. Task avoidance has been shown to be linked to mathematical skills during the first school years. Furthermore, task avoidance behavior in kindergarten-aged children has been shown to be linked to slower acquisition of mathematical skills in the course of school years. This study examines the prevalence and stability of task avoidance in kindergarten-aged children. Moreover, it was studied how children’s task avoidance was linked to mathematical skills and their development during the kindergarten year. The study was a longitudinal study (N = 235), where kindergartners’ mathematical skills, more precisely, the mastery of relations and number sequences, were evaluated by The Early Numeracy Test for Toddlers three times during one school year. In addition, task avoidance was evaluated by teachers in the first and last measurement points using the following variables: diffidence, difficulties in motivation, difficulties in attention, tension and cooperate difficulties. The data was analyzed by quantitative research methods. The kindergartners were divided into three groups based on the level of their task avoidance behavior: no problems (N = 128), some amount of problems (N = 86), lots of problems (N = 19). The children with most task avoidance behavior had weaker mathematical skills than the others in the beginning of kindergarten. Those belonging to the lots of problems -group improved the most during the kindergarten year, reaching the skill level of those with less task avoidance characteristics. The belonging to a task avoidance group was relatively stable during kindergarten, especially within the lots of problems -group. According to the results, children’s task avoidance should be monitored already in kindergarten to ensure the earliest possible support in terms of both task avoidance and mathematical skills. Further studies are needed to form a reliable overview on the developmental relationship between task avoidance and mathematical skills in children below school-age.
  • Oja, Anni (Helsingfors universitet, 2012)
    Hypoglykemia on hyvin tunnettu ongelma etenkin diabeetikoilla. Hypoglykemiassa veren glukoosipitoisuus laskee alle 2.7-3.0 mmol/l aiheuttaen potilaalle oireita. Yleensä oireet ovat ohimeneviä, mutta aiemman tutkimuksen perusteella on havaittu, että jatkuvana tai toistuvana hypoglykemia voi aiheuttaa lapsille jopa pysyviä aivovaurioita. Tämä tutkimus on tehty selvittämään syitä suomalaislasten päivystyskäyntiin johtaneiden hypoglykemioiden takana. Tieto on kerätty potilasasiakirjoista vuosina 2003-2008 ko. syystä Lasten ja nuorten sairaalan päivystyksessä käyneistä alle 18-vuotiaista lapsista, joita kertyi yhteensä 31. Tutkimukseen ei ole sisällytetty vastasyntyneiden hypoglykemiaproblematiikkaa. Huomiota kiinnitettiin etenkin hormonaalisiin veren glukoosipitoisuuden säätelyn häiriöihin kuten hypokortisolismiin. Tulokset osoittavat että yleisin syy hypoglykemiaan on tässä aineistossa ns. hyvänlaatuinen ketoottinen hypoglykemiataipumus. Muita yleisiä syitä ovat diabetekseen ja sen hoitoon liittyvät ongelmat ja infektiot kuten gastroenteriitti. Kortisolinerityksen häiriöt eivät näytä olevan suuressa roolissa hypoglykemian aiheuttajana.
  • Kujanpää, Riia (2007)
    Tässä pro gradu -tutkielmassa selvitän lastensuojelun jälkihuollossa olevien sekä olleiden nuorten kokemuksia jälkihuollon tuetusta asumisesta. Käsittelyni kohteena ovat nuorten siirtymävaiheet heidän muuttaessaan laitoksesta tukiasuntoon ja sieltä pois. Siirtymävaiheita tarkastelen ensisijaisesti Kyngäksen käyttämän siirtymävaihe käsitteen kautta. Lisäksi tarkastelen nuorten arkea sekä heidän tulevaisuuden toiveita. Tarkastelun kohteena on Helsingissä sijaitseva lastensuojelun tukiasuntoyksikkö, joiden tukiasunnoissa nuoret ovat asuneet. Yksikkö tarjoaa tuettua asumista jälkihuollossa oleville nuorille. Olen pyrkinyt tuomaan esille nuorten kokemukset ja ajatukset tukiasunnossa asumisesta, siirtymävaiheista ja niistä selviytymisen. Tutkimusaineistoni koostuu kahdeksan 20-21-vuotiaan nuoren teemahaastattelusta. Jokainen heistä on asunut lastensuojelun tukiasunnossa. Haastatteluhetkellä heistä jokainen oli asunut jo jonkin aikaa omillaan. Tutkimushaastattelut analysoin teemoittelua ja niin kutsuttua Framework-analyysiä hyväksi käyttäen. Tutkimusaihe on tärkeä, koska lastensuojelututkimuksen alueella on olemassa vain vähän tutkimustietoa jälkihuollosta. Laitoksessa asuessaan nuoret olivat odottaneet malttamattomina tukiasunnon saantia. He kaipasivat rauhaa ja vapautta. He ajattelivat yksin asuessaan kaiken olevan myös paljon helpompaa. Yksinäisyys ja turvattomuus yllättivät kuitenkin jokaisen nuoren heidän asuessaan yksin. He kaipasivat takaisin laitokseen. He kaipasivat lähelleen aikuisia ja muiden nuorten seuraa. Nuorten odotukset yksin asumisesta olivat paljon positiivisemmat kuin miksi todellisuus osoittautui. Nuoret kokivat muuton laitoksesta tukiasuntoon merkittävänä siirtymävaiheena elämässään, johon he tarvitsevat paljon tukea. Nuoret hakivat sosiaaliselta verkostoltaan tukea ja turvaa. Tukiasunnon työntekijän tarjoama sosiaalinen tuki oli ollut myös merkityksellistä ja tarpeellista nuorelle. Nuoret kokivat tulleensa kuulluiksi ja saaneensa vaikuttaa omiin asioihin. Tukiasunnossa asuessaan nuoret saivat harjoitella itsenäistä elämää saaden samalla työntekijältään apua ja tukea. Nuoret olivat pärjääviä ja heistä jokaisella oli tulevaisuuden unelmia ja haaveita. Nuoret olivat tyytyväisiä tukiasunto-yksikön palveluun ja siellä oleviin työntekijöihin. Moni nuorista olisi jäänyt vielä asumaan tukiasuntoon 1-2 vuodeksi, jos se olisi ollut mahdollista. Asuminen kuitenkin päättyy, kun nuori täyttää 21 vuotta ja oikeus jälkihuoltoon lakkaa. Tutkimusaineistoni koostuu pärjäävistä nuorista. Jatkotutkimuksien tulisikin kohdistua heikommin pärjääviin jälkihuoltonuoriin. Miten tavoittaa nämä nuoret ja saada heidän kokemuksensa esille. Miten kehittää sellaisia palveluja joissa nämä nuoret pärjäisivät ja joihin he sitoutuisivat.
  • Kivilä, Henriikka (2014)
    Recent climate related changes in the Arctic have risen concern and interest to better understand the mechamisms of arctic climate system and to predict the future reponse. Due to short instrumental monitoring a palaeoenvironmental view is required to reveal and understand long-term changes, yet high-resolution palaeoecological and -climatological studies are sparse. Bjørnøya, the Bear Island, (74°30' N, 19° E) is a key site for terrestrial palaeoclimate records along the heat transport system of the North Atlantic Current, with the possibility of linking records from northern Fennoscandia and Arctic Svalbard. A summer temperature series for the past ca. 1000 years was reconstructed from a 64 cm surface sediment core from lake Ellasjøen, SW Bjørnøya, based on quantitative palaeoenvironmental modelling of subfossilized chironomid assemblages. Quality of reconstructions was assessed with modern analogue techique and principal component analysis. To support the interpretation and receive a more holistic view of the lake history, in- lake processes, catchment interaction and factors behind the changes, a multi-proxy approach was chosen. Sediment physical characteristics: water content, loss-on-ignition, magnetic susceptibility and spectrocolorimetric identification of sedimentary signatures and components, in addition to composition and diversity of the chironomid assemblage, were used to trace a comprehensive picture of past changes. Radiometric dating was conducted to assess the temporal context of the sedimentary series. The results reveal that Ellasjøen is a climatically sensitive lake and preserves a history of substantial changes. A general pattern is detected where Medieval Warm Period features very modest warmth, followed by warming summer temperatures untill 1600 AD, when the temperature trend starts to decrease towards culmination of the Little Ice Age at 1740 AD. A warming trend ever since is persistent but does not exceed past warmth. Results suggest higher seasonality during Little Ice Age and seek to explain causes for modest recent warmth. Reconstructed climate development is in good agreement with recent results from surrounding areas and a complex set of ice-ocean-atmosphere interactions is proposed as driving factors. The findings of this study highlight the importance of regionally solved high-resolution climate records and tracing of seasonal climate components to fully understand the variation and interrelationship of driving factors affecting the Arctic climate dynamics in the eastern North Atlantic sector.
  • Vehviläinen, Piia (Helsingin yliopisto, 2010)
    Latent transforming growth factor-beta (TGF-beta) binding proteins (LTBPs) -1, -3 and -4 are ECM components whose major function is to augment the secretion and matrix targeting of TGF-beta, a multipotent cytokine. LTBP-2 does not bind small latent TGF-beta but has suggested functions as a structural protein in ECM microfibrils. In the current work we focused on analyzing possible adhesive functions of LTBP-2 as well as on characterizing the kinetics and regulation of LTBP-2 secretion and ECM deposition. We also explored the role of TGF-beta binding LTBPs in endothelial cells activated to mimic angiogenesis as well as in malignant mesothelioma. We found that, unlike most adherent cells, several melanoma cell lines efficiently adhered to purified recombinant LTBP-2. Further characterization revealed that the adhesion was mediated by alpha3beta1 and alpha6beta1 integrins. Heparin also inhibited the melanoma cell adhesion suggesting a role for heparan sulphate proteoglycans. LTBP-2 was also identified as a haptotactic substrate for melanoma cell migration. We used cultured human embryonic lung fibroblasts to analyze the temporal and spatial association of LTBP-2 into ECM. By We found that LTBP-2 was efficiently assembled to the ECM only in confluent cultures following the deposition of fibronectin (FN) and fibrillin-1. In early, subconfluent cultures it remained primarily in soluble form after secretion. LTBP-2 colocalized transiently with FN and fibrillin-1. Silencing of fibrillin-1 expression by lentiviral shRNAs profoundly disrupted the deposition of LTBP-2 indicating that the ECM association of LTBP-2 depends on a pre-formed fibrillin-1 network. Considering the established role of TGF-beta as a regulator of angiogenesis we induced morphological activation of endothelial cells by phorbol 12-myristate 13-acetate (PMA) and followed the fate of LTBP-1 in the endothelial ECM. This resulted in profound proteolytic processing of LTBP-1 and release of latent TGF-beta complexes from the ECM. The processing was coupled with increased activation of MT-MMPs and specific upregulation of MT1-MMP. The major role of MT1-MMP in the proteolysis of LTBP-1 was confirmed by suppressing the expression with lentivirally induced short-hairpin RNAs as well as by various metalloproteinases inhibitors. TGF-beta can promote tumorigenesis of malignant mesothelioma (MM), which is an aggressive tumor of the pleura with poor prognosis. TGF-beta activity was analyzed in a panel of MM tumors by immunohistochemical staining of phosphorylated Smad-2 (P-Smad2). The tumor cells were strongly positive for P-Smad2 whereas LTBP-1 immunoreactivity was abundant in the stroma, and there was a negative correlation between LTBP-1 and P-Smad2 staining. In addition, the high P-Smad2 immunoreactivity correlated with shorter survival of patients. mRNA analysis revealed that TGF-beta1 was the most highly expressed isoform in both normal human pleura and MM tissue. LTBP-1 and LTBP-3 were both abundantly expressed. LTBP-1 was the predominant isoform in established MM cell lines whereas the expression of LTBP-3 was high in control cells. Suppression of LTBP-3 expression by siRNAs resulted in increased TGF-beta activity in MM cell lines accompanied by decreased proliferation. Our results suggest that decreased expression of LTBP-3 in MM could alter the targeting of TGF-beta to the ECM and lead to its increased activation. The current work emphasizes the coordinated process of the assembly and appropriate targeting of LTBPs with distinct adhesive or cytokine harboring properties into the ECM. The hierarchical assembly may have implications in the modulation of signaling events during morphogenesis and tissue remodeling.
  • Kantola, Anna (Helsingin yliopisto, 2010)
    Extracellular matrix (ECM) is a complex network of various proteins and proteoglycans which provides tissues with structural strength and resilience. By harvesting signaling molecules like growth factors ECM has the capacity to control cellular functions including proliferation, differentiation and cell survival. Latent transforming growth factor β (TGF-β) binding proteins (LTBPs) associate fibrillar structures of the ECM and mediate the efficient secretion and ECM deposition of latent TGF-β. The current work was conducted to determine the regulatory regions of LTBP-3 and -4 genes to gain insight into their tissue-specific expression which also has impact on TGF-β biology. Furthermore, the current research aimed at defining the ECM targeting of the N-terminal variants of LTBP-4 (LTBP-4S and -4L), which is required to understand their functions in tissues and to gain insight into conditions in which TGF-β is activated. To characterize the regulatory regions of LTBP-3 and -4 genes in silico and functional promoter analysis techniques were employed. It was found that the expression of LTBP-4S and -4L are under control of two independent promoters. This finding was in accordance with the observed expression patterns of LTBP-4S and -4L in human tissues. All promoter regions characterized in this study were TATAless, GC-rich and highly conserved between human and mouse species. Putative binding sites for Sp1 and GATA family of transcription factors were recognized in all of these regulatory regions. It is possible that these transcription factors control the basal expression of LTBP-3 and -4 genes. Smad binding element was found within the LTBP-3 and -4S promoter regions, but it was not present in LTBP-4L promoter. Although this element important for TGF-β signaling was present in LTBP-4S promoter, TGF-β did not induce its transcriptional activity. LTBP-3 promoter activity and mRNA expression instead were stimulated by TGF-β1 in osteosarcoma cells. It was found that the stimulatory effect of TGF-β was mediated by Smad and Erk MAPK signaling pathways. The current work explored the ECM targeting of LTBP-4S and identified binding partners of this protein. It was found that the N-terminal end of LTBP-4S possesses fibronectin (FN) binding sites which are critical for its ECM targeting. FN deficient fibroblasts incorporated LTBP-4S into their ECM only after addition of exogenous FN. Furthermore, LTBP-4S was found to have heparin binding regions, of which the C-terminal binding site mediated fibroblast adhesion. Soluble heparin prevented the ECM association of LTBP-4S in fibroblast cultures. In the current work it was observed that there are significant differences in the secretion, processing and ECM targeting of LTBP-4S and -4L. Interestingly, it was observed that most of the secreted LTBP-4L was associated with latent TGF-β1, whereas LTBP-4S was mainly secreted as a free form from CHO cells. This thesis provides information on transcriptional regulation of LTBP-3 and -4 genes, which is required for the deeper understanding of their tissue-specific functions. Further, the current work elucidates the structural variability of LTBPs, which appears to have impact on secretion and ECM targeting of TGF-β. These findings may advance understanding the abnormal activation of TGF-β which is associated with connective tissue disorders and cancer.
  • Kubischta, Frauke (Helsingin yliopisto, 2011)
    The purpose of this study was to establish the palaeoenvironmental conditions during the late Quaternary in Murchisonfjorden, Nordaustlandet, based on foraminiferal assemblage compositions, and to determine the onset and termination of the Weichselian glaciations. The foraminiferal assemblage compositions were studied in marine sediments from three different archives, from sections next to the present shoreline in the Bay of Isvika, from a core in the Bay of Isvika and from a core from Lake Einstaken. OSL and AMS 14C age determinations were performed on samples from the three archives, and the results show deposition of marine sediments during ice-free periods of the Early Weichselian, the Middle Weichselian and the Late Weichselian, as well as during the Holocene in the investigated area. Marine sediments from the Early and Middle Weichselian were sampled from isostatically uplifted sections along the present shoreline.Sediments from the transition from the Late Weichselian to early Holocene time intervals were found in the bottom of the core from Lake Einstaken. Holocene sediments were investigated in the sections and in the core from the Bay of Isvika. The marine sediments from the sections are comprised of five benthic foraminiferal assemblages. The Early Weichselian is represented by two foraminiferal assemblages, the Middle Weichselian, the early and the late Holocene each by one. All five foraminiferal assemblages were deposited in glacier-distal shallow-water environments, which had a connection to the open ocean. Changes in the composition of the assemblages can be ascribed to differences in the bottom-water currents and changes in the salinity. The Middle Weichselian assemblage is of special importance, because it is the first foraminiferal assemblage to be described from this time interval from Svalbard. Four benthic foraminiferal assemblages were deposited shortly before the marine to lacustrine transition at the boundary between the Late Weichselian and Holocene in Lake Einstaken. The foraminiferal assemblages show a change from a high-arctic, normal marine shallow-water environment to an even shallower environment with highly fluctuating salinity. The analyses of the core from 100 m water depth in the Bay of Isvika resulted in the determination of four foraminiferal assemblages. These indicated changes from a glacier-proximal environment during deglaciation, to a more glacier-distal environment during the Early Holocene. This was followed by a period with a marked change to a considerably cooler environment and finally to a closed fjord environment in the middle and late Holocene times. Additional sedimentological analyses of the marine and glacially derived sediments from the uplifted sections, as well as observations of multiple striae on the bedrock, observations of deeply weathered bedrock and findings of tills interlayered with marine sediments complete the investigations in the study area. They indicate weak glacial erosion in the study area. It can be concluded that marine deposition occurred in the investigated area during three time intervals in the Weichselian and during most of the Holocene. The foraminiferal assemblages in the Holocene are characterized by a transition from glacier-proximal to glacier-distal faunas. The palaeogeographical change from an open fjord to a closed fjord environment is a result of the isostatic uplift of the area after the LGM and is clearly reflected in the foraminiferal assemblages. Another influencing factor on the foraminiferal assemblage composition are changes in the inflow of warmer Atlantic waters to the study area.
  • Jutila, Arimatti (Helsingin yliopisto, 2001)
  • Eklund, Mikaela (Helsingfors universitet, 2010)
    Turners syndrom beror på avsaknaden av en X kromosom antingen helt (45X), eller delvis (ex. mosaikismkaryotyper 45,X/46XX) och drabbar 1 på 2000 flickor, vilka karakteriseras av kortväxthet och utebliven sekundär könskaraktär. Medicineringen består av tillväxthormon och estrogen. Kraniofakialt ses retrognatiska käkar, en liten mandibula samt en stor kranialbasvinkel. I denna studie ville vi utreda ifall svalget påverkas då käkarna är retrognatiska. 35 skallateralbilder från flickor med Turners syndrom och 35 kontrollbilder från friska flickor i åldrarna 6.5-21 år undersöktes genom standard kefalometrisk analys med sex linjära och tio angulära mått som kompletterades med sex mått från svalget och jämfördes statisktiskt med parat T-test. Alla sex mått i svalget var mindre hos flickorna med Turners syndrom. Två av svalgmåtten var statisktiskt signifikant mindre, PNS-ad2 (p=0.019) och PAS (p=0.012). Detta betyder att syndromet antingen i sig, eller sekundärt i och med de retrognatiska käkarna, gör svalget smalare.