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Helsingin yliopiston tutkijoiden julkaisemia artikkeleja.

Helsingin yliopiston tutkijat voivat rinnakkaistallentaa tutkimusjulkaisujansa HELDAan liittämällä kokotekstin julkaisuun TUHAT-tutkimustietojärjestelmässä. (Toimintaohje tutkijalle)

Kokoelmat

Uusimmat julkaisut

  • Böttcher, Kristin; Rautiainen, Kimmo; Aurela, Mika; Kolari, Pasi; Mäkelä, Annikki; Arslan, Ali N.; Black, T. Andrew; Koponen, Sampsa (2018)
    Triggered by decreases in photoperiod and temperature, evergreen needle-leaved trees in the boreal region downregulate photosynthetic activity and enter dormancy in autumn. Accompanying changes in canopy structure and chlorophyll content are small and precede the cessation of photosynthetic activity. Low solar elevation and cloud cover during this period pose additional challenges for the use of optical satellite instruments. Alternatively, environmental variables that correlate with photosynthesis, such as soil freeze, can be detected from satellite microwave observations independent of weather and illumination conditions. We tested for the first time the usability of satellite-observed soil freeze from the Soil Moisture and Ocean Salinity (SMOS) instrument as a proxy indicator for the end of vegetation active period (VAPend) at six eddy covariance sites in Finland and Canada. The time when soil freeze commenced over the large SMOS pixel can be employed to estimate VAPend (R-2=0.84, RMSE=7.5days), defined as the time when the photosynthetic capacity of the forest drops below 10% of the growing season maximum. In comparison to satellite-based soil freeze timing, an air temperature-based proxy from ERA-Interim reanalysis data showed better performance (R-2=0.92, RMSE=5.2days). VAPend was mapped in the boreal forest zone in Finland and Canada from both indicators based on linear regression models.
  • Jogiste, Kalev; Frelich, Lee E.; Laarmann, Diana; Vodde, Floortje; Baders, Endijs; Donis, Janis; Jansons, Arts; Kangur, Ahto; Korjus, Henn; Köster, Kajar; Kusmin, Jurgen; Kuuluvainen, Timo; Marozas, Vitas; Metslaid, Marek; Metslaid, Sandra; Polyachenko, Olga; Poska, Anneli; Rebane, Sille; Stanturf, John A. (2018)
    In the Baltic States region, anthropogenic disturbances at different temporal and spatial scales mostly determine dynamics and development phases of forest ecosystems. We reviewed the state and condition of hemiboreal forests of the Baltic States region and analyzed species composition of recently established and permanent forest (PF). Agricultural deforestation and spontaneous or artificial conversion back to forest is a scenario leading to ecosystems designated as recent forest (RF, age up to two hundred years). Permanent forest (PF) was defined as areas with no records of agricultural activity during the last 200 yr, including mostly forests managed by traditional even-aged (clear-cut) silviculture and salvage after natural disturbances. We hypothesized that RF would have distinctive composition, with higher dominance by hardwoods (e.g., aspen and birch), compared to PF. Ordination revealed divergence in the RF stands; about half had the hypothesized composition distinct from PF, with a tight cluster of stands in the part of the ordination space with high hardwood dominance, while the remaining RF stands were scattered throughout the ordination space occupied by PF with highly variable species composition. Planting of conifers, variability in site quality, and variability in spatial proximity to PF with relatively natural ecosystem legacies likely explained the variable compositions of this latter group of RF. We positioned the observations of RF in a classic quantification of site type conditions (based on Estonian forest vegetation survey previously carried out by LA mu hmus), which indicated that RF was more likely to occur on areas of higher soil fertility (in ordination space). Climatic and anthropogenic changes to RF create complex dynamic trends that are difficult to project into the future. Further research in tracing land use changes (using pollen analysis and documented evidence) should be utilized to refine the conceptual framework of ecosystem legacy and memory. Occurrence and frequency of deforestation and its characteristics as a novel disturbance regime are of particular interest.
  • Lainà, Patrizio (2018)
  • Nemitz, Eiko; Mammarella, Ivan; Ibrom, Andreas; Aurela, Mika; Burba, George G.; Dengel, Sigrid; Gielen, Bert; Grelle, Achim; Heinesch, Bernard; Herbst, Mathias; Hörtnagl, Lukas; Klemedtsson, Leif; Lindroth, Anders; Lohila, Annalea; McDermitt, Dayle K.; Meier, Philip; Merbold, Lutz; Nelson, David; Nicolini, Giacomo; Nilsson, Mats B.; Peltola, Olli; Rinne, Janne; Zahniser, Mark (2018)
    Commercially available fast-response analysers for methane (CH4) and nitrous oxide (N2O) have recently become more sensitive, more robust and easier to operate. This has made their application for long-term flux measurements with the eddycovariance method more feasible. Unlike for carbon dioxide (CO2) and water vapour (H2O), there have so far been no guidelines on how to optimise and standardise the measurements. This paper reviews the state-of-the-art of the various steps of the measurements and discusses aspects such as instrument selection, setup and maintenance, data processing as well as the additional measurements needed to aid interpretation and gap-filling. It presents the methodological protocol for eddy covariance measurements of CH4 and N2O fluxes as agreed for the ecosystem station network of the pan-European Research Infrastructure Integrated Carbon Observation System and provides a first international standard that is suggested to be adopted more widely. Fluxes can be episodic and the processes controlling the fluxes are complex, preventing simple mechanistic gap-filling strategies. Fluxes are often near or below the detection limit, requiring additional care during data processing. The protocol sets out the best practice for these conditions to avoid biasing the results and long-term budgets. It summarises the current approach to gap-filling.
  • Räsänen, Jenni; Oikkonen, Juha; Aksela, Maija (2018)
    There is a need to organize non-formal learning activities in mathematics for children and youth. In Finland, we are developing a new non-formal learning environment called Pulmaario where we use peer tutors as instructors. This study is the empirical problem analysis of the design-based research. The aim was to find out what kind of support the instructors of the Pulmaario learning environment felt they need. The research material (N=51) was collected with questionnaires. The analysis of the questionnaires was based on the method of inductive content analysis. The results shows the needs for developing the non-formal learning environment further.
  • Kaasila, Raimo; Laine, Anu (Niilo Mäki Instituutti, 2018)
  • Laine, Anu; Huhtala, Sissi; Kaasila, Raimo (Niilo Mäki Instituutti, 2018)
  • Rasila, Tiina; Saavalainen, Olga; Attalla, Hesham; Lankila, Petri; Haglund, Caj; Hölttä, Erkki; Andersson, Leif C. (2019)
    Our group originally found and cloned cDNA for a 98 kDa type 1 transmembrane glycoprotein of unknown function. Due to its abundant expression in astrocytes it was called the protein astroprincin (APCN). Two thirds of the evolutionarily conserved protein is intracytoplasmic whereas the extracellular domain carries two N-glycosidic side chains. APCN is physiologically expressed in placental trophoblasts, skeletal and hearth muscle, and kidney and pancreas. Overexpression of APCN (cDNA) in various cell lines induced sprouting of slender projections whereas knockdown of APCN expression by siRNA caused disappearance of actin stress fibres. Immunohistochemical staining of human cancers for endogenous APCN showed elevated expression in invasive tumor cells compared to intratumoral cells. Human melanoma cells (SK-MEL-28) transfected with APCN cDNA acquired ability of invasive growth in semisolid medium (Matrigel) not seen with control cells. A conserved carboxyterminal stretch of 21 amino acids was found to be essential for APCN to induce cell sprouting and invasive growth. Yeast-2-hybrid screening revealed several interactive partners of which ornithine decarboxylase (ODC) antizyme-1, NEEP21 (NSG1), and ADAM10 were validated by co-immunoprecipitation. This is the first functional description of APCN. These data show that APCN regulates the dynamics of the actin cytoskeletal and thereby the cell shape and invasive growth potential of tumor cells.
  • Mäkelä, Miia Riitta; Di Falco, M.; McDonnell, E.; Nguyen, T.T.M.; Wiebenga, A.; Hilden, Sari Kristiina; Peng, M.; Grigoriev, I.V.; Tsang, A.; de Vries, R.P. (2018)
    We classified the genes encoding carbohydrate-active enzymes (CAZymes) in 17 sequenced genomes representing 16 evolutionarily diverse Aspergillus species. We performed a phylogenetic analysis of the encoding enzymes, along with experimentally characterized CAZymes, to assign molecular function to the Aspergilli CAZyme families and subfamilies. Genome content analysis revealed that the numbers of CAZy genes per CAZy family related to plant biomass degradation follow closely the taxonomic distance between the species. On the other hand, growth analysis showed almost no correlation between the number of CAZyme genes and the efficiency in polysaccharide utilization. The exception is A. clavatus where a reduced number of pectinolytic enzymes can be correlated with poor growth on pectin. To gain detailed information on the enzymes used by Aspergilli to breakdown complex biomass, we conducted exoproteome analysis by mass spectrometry. These results showed that Aspergilli produce many different enzymes mixtures in the presence of sugar beet pulp and wheat bran. Despite the diverse enzyme mixtures produced, species of section Nigri, A. aculeatus, A. nidulans and A. terreus, produce mixtures of enzymes with activities that are capable of digesting all the major polysaccharides in the available substrates, suggesting that they are capable of degrading all the polysaccharides present simultaneously. For the other Aspergilli, typically the enzymes produced are targeted to a subset of polysaccharides present, suggesting that they can digest only a subset of polysaccharides at a given time.
  • Sukhenko, Inna (2018)
    30-year experience of studying “Chernobyl narrative” as a (non)fiction response to the explosion at Chernobyl nuclear energy plant (26 April, 1986) reveals that Chernobyl as a real urban Soviet City transferred into the amalgamation of its symbolic images such as a symbol of “Human-Nature” battle, an huge piece of abundant urban area, a Nature’s domination, a protector from “peaceful atom”, a tomb of the Soviet regime, selfdestroying science, a part of “private historical memory”, an unhealthy fascination (by A. Korzeniowska-Bihun), and even as a litmus test that shows the attitude of the authorities towards their own society both in the 1980s and even in the time of 2013/2014, followed by the military events. Nowadays shaped by the unique human-environment relationships, the digital society determines the transmedial transformations of “Chernobyl” perception within the convergent media culture (creating on/off-line activities – computer games S.T.A.L.K.E.R., ZONE; Chernobyl VR Project; Zone-tourism), which made “the Exclusion Zone” a subject of commodification stressing the commercialization of a nuclear disaster. “Chernobyl” extended the limits of real (and even “literary”) zone and changed into a digital place, where the S.T.A.L.K.E.R. universe hosts virtual characters-players wearing Exoskeletons or classic Monolith suits with gas masks and equipped with powerful weapons and aiming to reach Chernobyl Sarcopaghus and refuse Common Consciousness” Such aspect of the research is focused on studying the transformations of ”Chernobyl” (as a subject/object of commercial relations) within urban studies in the aspect of distinguishing local/global dimensions of “nuclear narrative” while stressing its implementation in shaping the “provincialized” nuclear culture. Studying the commercialized “Chernobyl” in “nuclear humanities” gives an opportunity to distinguish the local/global features of the urban studies in the context of researching ecological memory and nuclear identity in the post-traumatic societies.
  • Sukhenko, Inna (2018)
    The explosion at Chornobyl nuclear power plant (26 April, 1986) in the literary perspectve not only launched a new signifcant epoch of the Ukrainian nuclear discourse but also reconsidered the archetypes within the Ukrainian nuclear narratve. The transformatons of Madonna’s image in the Chornobyl literary responses to the disaster are under study here in the “provincializing” ecocritcal aspects of researching “nuclear narratve” within nuclear environmental humanites. In Ukrainian culture traditon this archetype is a milestone of the collectve unconsciousness of the Ukrainian people as well as a source of shaping new images which makes this “female” motve as a central one in the Ukrainian literature. In the Chornobyl narratve Madonna, the Mother of God is represented as a multfaceted image of a Slavic woman, which combines several female reincarnations which allows the integrated image of Madonna to split into some components in the historical and social perspectves. Appealing to the biblical character – Madonna, the Mother of God – within the Ukrainian nu within the Ukrainian nuclear narrative allows distinguishing the local/global dimensions of writing practices in the context of studying the correlations between human beings’ activity within “Atom for Peace” initiative and the tools of shaping “nuclear identity” within the ecocritical vision to ecological memory and ecological consciousness formation under the global/national/regional social needs in the post-trauma societies. Stressing the national as well as global nuclear tragedy in the light of reconsidering the Gospel legends and under the contemporary social and economic energy-related issues, such perspective on the image of Mary the Saint in Ukrainian nuclear fiction not only challenges the humanity for checking its power but also encourage the global features of a nuclear disaster in its literary dimensions in the aspect of current ecocritical parameters. The image of Madonna is very symbolic in its connotations of salvation, sacrifice and hope. The image of the Chornobyl Madonna embodies Ukraine as the soul of Ukrainian people, devoted to faith, hope and love, but at the same time this image is related to the global tendencies of depicting a nuclear disaster in the post-Chornobyl fiction, under the influence of ecocritical studies, nuclear criticism and environmental humanities
  • Sukhenko, Inna (Routledge, 2018)
    Researching the literary dimensions of the “Chernobyl” narrative in writing practices about the Chernobyl nuclear power plant explosion gives an opportunity to distinguish the local and global features of the “Chernobyl Syndrome” in post-Cold-War societies. The “Chernobyl Syndrome” (nuclear phobia, “nuclear energy” ignorance, the rejection of nuclear studies, health problem aftermath, forceful resettlement, etc.) is studied here through the risk communication parameters (Fahlquist and Roeser 2015) in US nuclear fiction. The analysis focuses on the “Chernobyl Syndrome” in US nuclear fiction (Pohl’s Chernobyl (1988), White’s Radiant Girl (2008), and Stelmach’s The Boy from Reactor 4 (2013)), depicting the Chernobyl nuclear power plant explosion and its aftermath. Relying upon such concepts as “hyber object frame” (Morton 2013), “intergenerational memory” studies (Lindsey 2014), and “literary energy narrative” studies (Goodbody 2018), the chapter aims to contribute to our understanding of “nuclear communication” aspects of the “Chernobyl Syndrome.”
  • Toppila-Salmi, Sanna; Rihkanen, Heikki; Arffman, Martti; Manderbacka, Kristiina; Keskimäki, Ilmo; Hytönen, Maija L. (2018)
    Objectives Endoscopic sinus surgery (ESS) is a common operation typically performed due to chronic rhinosinusitis (CRS). There are limited data on the nationwide ESS rate and factors contributing to its regional variation. The aim was to evaluate factors causing variation of ESS rate. Design Cross-sectional nationwide observational study. Setting A II patients undergoing ESS in Finland 2013-2015. Population Nationwide Finnish population aged 15 years or over. Main outcome measures ESS rate per 1000 inhabitants between 2013 and 2015 in all 21 hospital districts and independent factors for multilevel model analyses. Methods We used the Finnish register data of all patients with CRS who underwent ESS in 2013-2015. Patients aged under 15 years and those with ESS due to neoplasia were excluded. The age and gender standardised ESS rates were calculated, and multilevel Poisson regression models were used to evaluate variation in ESS in the 21 hospital districts. The likelihood ratio test was applied to assess the statistical significance of random components in the models. Results The nationwide annual rate of ESS is 0.71 per 1000 people in Finland. Hospital district rates varied from 0.25/1000 (95% CI 0.18 to 0.32) to 1.15/1000 (95% CI 1.09 1.21). Compared with males, females undergo ESS significantly more frequently (57% of the procedures), more often due to CRS without nasal polyps, and at a younger age (mean age 44.2 and 46.2 years, correspondingly). Multilevel analyses showed that lower age (between 24 years and 45 years) and availability/ease of medical services were independently associated with higher ESS rates. Conclusions This study confirms marked regional variation in the ESS rate in Finland, explained only in part by patients' age and differing availability of medical services. To analyse ESS across different CRS phenotypes or to compare quality registers on ESS properly, more research on regional variation is needed.
  • DiLeo, Michelle F.; Husby, Arild; Saastamoinen, Marjo (2018)
    There is now clear evidence that species across a broad range of taxa harbor extensive heritable variation in dispersal. While studies suggest that this variation can facilitate demographic outcomes such as range expansion and invasions, few have considered the consequences of intraspecific variation in dispersal for the maintenance and distribution of genetic variation across fragmented landscapes. Here, we examine how landscape characteristics and individual variation in dispersal combine to predict genetic structure using genomic and spatial data from the Glanville fritillary butterfly. We used linear and latent factor mixed models to identify the landscape features that best predict spatial sorting of alleles in the dispersal-related gene phosphoglucose isomerase (Pgi). We next used structural equation modeling to test if variation in Pgi mediated gene flow as measured by F-st at putatively neutral loci. In a year when the population was recovering following a large decline, individuals with a genotype associated with greater dispersal ability were found at significantly higher frequencies in populations isolated by water and forest, and these populations showed lower levels of genetic differentiation at neutral loci. These relationships disappeared in the next year when metapopulation density was high, suggesting that the effects of individual variation are context dependent. Together our results highlight that (1) more complex aspects of landscape structure beyond just the configuration of habitat can be important for maintaining spatial variation in dispersal traits and (2) that individual variation in dispersal plays a key role in maintaining genetic variation across fragmented landscapes.
  • Hognert, Helena; Skjeldestad, Finn Egil; Gemzell-Danielsson, Kristina; Heikinheimo, Oskari; Milsom, Ian; Lidegaard, Ojvind; Lindh, Ingela (2018)
    Objectives Compare hormonal contraceptive use, birth and abortion rates among teenagers in the Nordic countries. A secondary aim was to explore plausible explanations for possible differences between countries. Design Ecological study using national registry data concerning births and abortions among all women aged 15-19 years residing in Denmark, Finland, Iceland, Norway and Sweden 2008-2015. Age-specific data on prescriptions for hormonal contraceptives for the period 2008-2015 were obtained from national databases in Denmark, Norway and Sweden. Setting Denmark, Finland, Iceland, Norway and Sweden. Participants Women 15-19 years old in all Nordic countries (749 709) and 13-19 years old in Denmark, Norway and Sweden (815 044). Results Both annual birth rates and abortion rates fell in all the Nordic countries during the study period. The highest user rate of hormonal contraceptives among 15-19-year-olds was observed in Denmark (from 51% to 47%) followed by Sweden (from 39% to 42%) and Norway (from 37% to 41%). Combined oral contraceptives were the most commonly used methods in all countries. The use of long-acting reversible contraceptives (LARC), implants and the levonorgestrel-releasing intrauterine systems, were increasing, especially in Sweden and Norway. In the subgroup of 18-19-year-old teenagers, the user rates of hormonal contraceptives varied between 63% and 61% in Denmark, 56% and 61% in Norway and 54% and 56% in Sweden. In the same subgroup, the steepest increase of LARC was seen, from 2% to 6% in Denmark, 2% to 9% in Norway and 7% to 17% in Sweden. Conclusions Birth and abortion rates continuously declined in the Nordic countries among teenagers. There was a high user rate of hormonal contraceptives, with an increase in the use of LARC especially among the oldest teenagers.
  • Vennerström, Pia; Välimäki, Elina; Hautaniemi, Maria; Lyytikainen, Tapani; Kapiainen, Suvi; Vidgren, Gabriele; Virtala, Anna-Maija (2018)
    Wild fish were suspected to be the source of reinfection by viral haemorrhagic septicaemia virus (VHSV) in Finnish brackish water rainbow trout farms located in a restriction zone regarding viral haemorrhagic septicaemia (VHS) comprising the entire Province of Aland, Baltic Sea, in the 2000s. Altogether, 1636 wild fish of 17 different species living in the vicinity of infected fish farms were screened for VHSV during the years 2005-2008. Additionally, 2 uninfected wild fish species as well as farmed whitefish were introduced into a VHS-positive fish farm to test whether they became infected by VHSV from the clinically diseased rainbow trout. Wild fish did not test positive for VHSV on any occasion. In contrast, whitefish introduced to a VHS-positive farm were infected with VHSV genotype Id and started to replicate the virus for a short time during the trial. Whitefish are farmed together with, or in the vicinity of, farmed rainbow trout in the study area and, according to this study, are a possible source of the recurring infection in the restriction area. A sprivivirus was isolated from all fish species in the infection trial without causing mortality in the test groups.
  • University of Helsinki, Department of Digital Humanities; Zampieri, Marcos; Nakov, Preslav; Ljubesic, Nikola; Tiedemann, Jörg; Malmasi, Shervin; Ali, Ahmed; ; ; (Association for Computational Linguistics, 2018)
  • Kallio-Kujala, I. J.; Bennett, R. C.; Raekallio, M. R.; Yatkin, E.; Meierjohann, A.; Savontaus, E.; Scheinin, M.; Spillmann, T.; Vainio, O. M. (2018)
    The commonly used sedative alpha(2)-adrenoceptor agonist dexmedetomidine has adverse cardiovascular effects in dogs that can be prevented by concomitant administration of the peripherally acting alpha(2)-adrenoceptor antagonist MK-467. An ancillary effect of dexmedetomidine is to decrease insulin release from the pancreas, whereas MK-467 stimulates insulin release. This study assessed the effects of co-administered dexmedetomidine and MK-467 in a canine glibenclamide-induced hypoglycaemia model. In a randomised, cross-over experiment, eight beagle dogs received five intravenous treatments, comprising two administrations of saline, with dexmedetomidine or dexmedetomidine and MK-467, and three administrations of glibenclamide, with saline, dexmedetomidine or dexmedetomidine and MK-467. Plasma concentrations of glucose, lactate, insulin, glucagon and the test drugs were monitored. Administration of glibenclamide significantly increased insulin secretion and decreased blood glucose concentrations. Dexmedetomidine counteracted glibenclamide-evoked hypoglycaemia. This was opposed by the alpha(2)-adrenoceptor antagonist MK-467, but the glibenclamide-evoked hypoglycaemia was not potentiated by co-administration of dexmedetomidine and MK-467. None of the dogs developed uncontrolled hypoglycaemia. Thus, the combination of dexmedetomidine and MK-467 appeared to be safe in this canine hypoglycaemia model. Nevertheless, when MK-467 is used to alleviate the undesired cardiovascular effects of alpha(2)-adrenoceptor agonists in dogs, it should be used with caution in animals at risk for hypoglycaemia because of its insulin-releasing and hypoglycaemic effects. (C) 2018 The Author(s). Published by Elsevier Ltd.
  • Wiklund, Satu Mari-Anna (2017)
    Tytöt saavat nykyään keskimäärin korkeampia arvosanoja kuin pojat kaikissa oppiaineissa, ja uusimpien PISA-testien valossa kuilu tyttöjen ja poikien menestyksen välillä on kasvanut hälyttävästi: erot tyttöjen ja poikien menestyksen välillä ei ole missään muualla niin näkyvä kuin Suomessa. Tässä artikkelissa tyttöjen ja poikien arvosanaeroja tarkastellaan PISA-testien valossa. Lisäksi pohditaan motivaation ja koulumenestyksen yhteyttä eri näkökulmista. PISA-testien yhteydessä teetetyt kyselyt nimittäin paljastavat, että tytöillä on huomattavasti poikia korkeammat tavoitteet koulutuksen ja tulevan ammatin suhteen. Tämä viittaisi siihen, että poikien motivaatio koulutyötä kohtaan on vähäisempää kuin tytöillä. Moni poika kokeekin koulun ja omien kiinnostuksen kohteidensa kulkevan eri suuntiin. Koulu ei siis tunnu koskettavan heitä henkilökohtaisesti. Tytöt saattavat löytää koulumaailmasta poikia enemmän kosketuspinta-alaa suhteessa omiin kiinnostuksen kohteisiinsa. Tyttöjen ja poikien arvosanoissa on niin suuri ero, että tämä vaikuttaa heidän mahdollisuuksiinsa toisen asteen koulutukseen hakeuduttaessa. Poikien tyttöjä alhaisempi koulumotivaatio näyttäisikin heijastuvan jo siihenkin, kuinka suuri osa pojista suorittaa toisen asteen koulutuksen tai korkeakoulututkinnon. Opettajankoulutuksessa tulisi siis ehkä jatkossa kiinnittää entistä enemmän huomiota tasa-arvokasvatuksen vaatimuksiin sekä tyttöjen ja poikien yhdenvertaiseen huomioimiseen ja tukemiseen. Harrastusten ja koulutyön nykyistä tehokkaampi linkittäminen toisiinsa saattaisi myös hyödyttää joitakin oppilaita.
  • Sippola, Suvi; Grönroos, Juha; Sallinen, Ville; Rautio, Tero; Nordström, Pia; Rantanen, Tuomo; Hurme, Saija; Leppäniemi, Ari; Meriläinen, Sanna; Laukkarinen, Johanna; Savolainen, Heini; Virtanen, Johanna; Salminen, Paulina (2018)
    Introduction Recent studies show that antibiotic therapy is safe and feasible for CT-confirmed uncomplicated acute appendicitis. Spontaneous resolution of acute appendicitis has already been observed over a hundred years ago. In CT-confirmed uncomplicated acute diverticulitis (left-sided appendicitis), studies have shown no benefit from antibiotics compared with symptomatic treatment, but this shift from antibiotics to symptomatic treatment has not yet been widely implemented in clinical practice. Recently, symptomatic treatment of uncomplicated acute appendicitis has been demonstrated in a Korean open-label study. However, a double-blinded placebo-controlled study to illustrate the role of antibiotics and spontaneous resolution of uncomplicated acute appendicitis is still lacking. Methods and analysis The APPAC III (APPendicitis ACuta III) trial is a multicentre, double-blind, placebo-controlled, superiority randomised study comparing antibiotic therapy with placebo in the treatment CT scan-confirmed uncomplicated acute appendicitis aiming to evaluate the role of antibiotics in the resolution of uncomplicated acute appendicitis. Adult patients (18-60 years) with CT scan-confirmed uncomplicated acute appendicitis (the absence of appendicolith, abscess, perforation and tumour) will be enrolled in five Finnish university hospitals. Primary endpoint is success of the randomised treatment, defined as resolution of acute appendicitis resulting in discharge from the hospital without surgical intervention within 10 days after initiating randomised treatment (treatment efficacy). Secondary endpoints include postintervention complications, recurrent symptoms after treatment up to 1year, late recurrence of acute appendicitis after 1year, duration of hospital stay, sick leave, treatment costs and quality of life. A decrease of 15 percentage points in success rate is considered clinically important difference. The superiority of antibiotic treatment compared with placebo will be analysed using Fisher's one-sided test and CI will be calculated for proportion difference. Ethics and dissemination This protocol has been approved by the Ethics Committee of Turku University Hospital and the Finnish Medicines Agency (FIMEA). The findings will be disseminated in peer-reviewed academic journals. Trial registration number NCT03234296; Pre-results.

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