15 results on '"Komulainen, T."'
Search Results
2. Preservice subject teachers’ lack of interest in their minor subject:is it a problem?
- Author
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Havia, J. (Johanna), Lutovac, S. (Sonja), Komulainen, T. (Tiina), Kaasila, R. (Raimo), Havia, J. (Johanna), Lutovac, S. (Sonja), Komulainen, T. (Tiina), and Kaasila, R. (Raimo)
- Abstract
Interest in a particular subject is one central factor in preservice teachers’ decision to become subject teachers. Interest in a subject can also become visible in preservice teachers’ teaching and may consequently impact their students’ interest in the subject. However, the interest of preservice teachers in their major and minor subjects has been scarcely addressed. In Finland, secondary school teachers usually study and teach two or three subjects. Major subjects are often chosen based on interest; however, the reasons for choosing a minor subject can vary. In this study, we examined the narratives of three preservice subject teachers regarding their interest in their minor and major subjects. They all studied mathematics, physics, and chemistry and revealed a much weaker interest in the minor subjects compared to the major subjects. Interestingly, our findings also reveal that preservice teachers’ perceived strengths in a specific subject may not be as crucial to their interests, as has been suggested by prior research. We discuss the consequences of preservice teachers’ weaker interest in certain subjects and provide recommendations for teacher education.
- Published
- 2022
3. Streak detection and analysis pipeline for space-debris optical images
- Author
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Virtanen, Jenni, Poikonen, J., Säntti, T., Komulainen, T., Torppa, J., Granvik, M., Muinonen, Karri, Pentikäinen, H., Martikainen, J., Näränen, Jyri, Lehti, J., Flohrer, T., National Land Survey of Finland, and Maanmittauslaitos
- Published
- 2016
4. 'Iäti tulevat laivat kulkemaan tästä ohi':Ellin tarina ja kehitysromaanin murros Ahon Papin tytär- ja Papin rouva -romaaneissa
- Author
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Vornanen-Komulainen, T. (Tuula)
- Subjects
Literature - Abstract
Tutkielmassa selvitetään, miten 1800-luvun loppupuolella alkanut kehitysromaanin murros ilmenee Juhani Ahon romaaneissa Papin tytär (1885) ja Papin rouva (1893). Kehitysromaani nousi keskeiseksi kirjallisuudenlajiksi modernin ihmiskäsityksen syntyaikoihin. Moderniin ihmiskäsitykseen kuului, ettei ihminen omaksunut valmista, perittyä elämänmuotoa, vaan etsi omaa identiteettiään ja paikkaansa yhteiskunnassa. Tätä kehitysromaanille tyypillistä, jo 1700-luvulta peräisin olevaa ajatusta alettiin kritisoida sata vuotta myöhemmin. Yksilöllisen kasvuprosessin murtuminen on lähtökohtana teosten tarkastelussa. Realismin aikakaudella henkilöhahmot olivat erityisesti mielenkiinnon kohteina. Molempien teosten päähenkilönä on Elli, jonka kasvu ja kehitys ovat tutkielmassa keskeisellä sijalla. Päähenkilö ei ole romaanissa enää juonta teenpäin vievä toimija, vaan ainutlaatuinen yksilö, jonka luonteen ymmärtämisestä riippuu koko teoksen ymmärtäminen. Henkilökuvaukseen läheisesti liittyvät arjen kuvaukset tuovat mukaan myös yhteiskunnallisen todellisuuden. Ellin kasvatuksesta ja koulutuksesta käydyt keskustelut liitetään 1800-luvun yleisiin käsityksiin sivistyksestä, kasvatuksesta ja koulutuksesta. Koska realistisessa kirjallisuudessa teosten väliset suhteet ovat tärkeitä teosten illuusioiden luomisessa, Papin tytärtä ja Papin rouvaa tarkastellaan myös intertekstuaalisesta näkökulmasta käsin. Papin tytär ja Papin rouva sijoittuvat murroskohtaan realismin aikakauden kehitysromaaniperinteessä. 1800-luvun lopussa suoraviivaisesti aikuisuuteen ja oman paikan löytymiseen etenevä kehitystarina alkoi väistyä toisenlaisen totuuden tieltä. Eheän identiteetin sijaan Ellille muotoutuu hajanainen, ristiriitojen repimä minuus.
- Published
- 2015
5. Disturbances in mitochondrial DNA maintenance in neuromuscular disorders and valproate-induced liver toxicity
- Author
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Komulainen, T. (Tuomas), Uusimaa, J. (Johanna), Majamaa, K. (Kari), and Rantala, H. (Heikki)
- Subjects
mitokondrio-DNA ,n deleetio [mitokondrio-DNA] ,liver failure ,neuromuskulaariset sairaudet ,mitochondrial DNA ,neuromuscular disorders ,n depleetiosyndrooma [mitokondrio-DNA] ,mitochondrial DNA depletion syndrome ,drug toxicity ,mitokondriotaudit ,POLG1-geeni ,POLG1 gene ,vaikea maksan vajaatoiminta ,valproaatti ,mitochondrial DNA deletions ,sodium valproate ,lääketoksisuus - Abstract
Mitochondrial DNA depletion and deletions are related to mutations in the nuclear genes responsible for replication and maintenance of mitochondrial DNA (mtDNA). The POLG1 gene encodes the enzyme responsible for replication of mtDNA. A particular feature of the POLG1 mutations is an increased risk of acute liver failure (ALF) upon exposure to sodium valproate (VPA), but the pathomechanism is not resolved. The present work studies the molecular genetic aetiology and clinical phenotypes associated with mtDNA depletion and deletion. Another objective was an investigation of clinical phenotypes in POLG1 mutations and disentangling the pathomechanism of VPA-induced ALF in POLG1 mutations. Mitochondrial toxicity of VPA was examined using HepG2 cells as an experimental in vitro model. In this work, mtDNA depletion was associated with severe neonatal-onset encephalopathy. Furthermore, mtDNA depletion was found in muscle dystrophy as a secondary finding to muscle degradation. Multiple mitochondrial DNA deletions were found in two patients with Kearns-Sayre syndrome suggesting a genetic origin of the disease. POLG1 p.R722H mutation has been previously reported as a neutral polymorphism, but we found evidence suggesting that POLG1 p.R722H could be a pathogenic mutation in a homozygous or compound heterozygous state. We identified retrospectively five patients, who required liver transplant after VPA-induced ALF. All five patients harboured POLG1 mutations supporting the evidence of POLG1 mutations as a risk factor for VPA-induced ALF. Previously, patients with POLG1 mutations have been considered unsuitable for liver transplantation, but we found that homozygous POLG1 mutations and adolescent or adult-onset disease predicted a good outcome following liver transplantation. In vitro studies on HepG2 cells showed that VPA disturbs mitochondrial respiration. Our results expand the phenotypes and molecular genetic features in mitochondrial DNA depletion and deletion syndromes. We found evidence that POLG1 mutations are not a contraindication for liver transplantation; rather, mutation status and age at onset affect survival. This finding should be taken in consideration in the treatment of VPA-induced ALF. Furthermore, our findings indicate that sodium valproate is toxic to mitochondria and should be avoided in patients with mitochondrial disease. Tiivistelmä Mitokondrion DNA:n (mtDNA) kahdentumisesta ja ylläpidosta vastaavien tuman geenien mutaatiot voivat johtaa mtDNA:n määrän vähenemiseen (depleetioon) ja katkoksiin (deleetioihin). MtDNA:n kahdentumisesta vastaavaa entsyymiä koodaa tuman POLG1-geeni. POLG1-mutaatioihin liittyy kohonnut riski sairastua natriumvalproaatin (VPA) aiheuttamaan akuuttiin maksavaurioon. Tutkimuksen tavoitteena oli tutkia mtDNA:n depleetion ja deleetioiden molekyyligeneettistä etiologiaa ja kliinisiä taudinkuvia. Tutkimuksessa selvitettiin myös POLG1-mutaatioihin liittyviä taudinkuvia ja POLG1-mutaatioihin liittyvän akuutin maksavaurion patomekanismia. VPA:n vaikutusta mitokondrioiden toimintaan tutkittiin in vitro HepG2-solumallissa. Tutkimuksessa todettiin mtDNA:n depleetion liittyvän vaikeaan varhain alkavaan aivosairauteen. Depleetio todettiin myös sekundaarisena merosiini-negatiivisessa lihasdystrofiassa. Kahdella Kearns-Sayren syndroomaa sairastavalla potilaalla todettiin multippelit mtDNA:n deleetiot, mikä viittaa syndrooman geneettisen alkuperään. POLG1 p.R722H-mutaatiota on aiemmin pidetty neutraalina polymorfiana, mutta tutkimuksen tulokset viittasivat siihen, että homotsygoottisena tai yhdistelmäheterotsygoottisena mutaatio on tautia aiheuttava. Helsingin yliopistollisen sairaalan elinsiirtorekisteristä tunnistettiin retrospektiivisesti viisi potilasta, jotka olivat saaneet maksansiirteen VPA:n aiheuttaman maksavaurion vuoksi. Kaikilla viidellä potilaalla todettiin POLG1-geenin mutaatio, mikä vahvistaa käsitystä geenin yhteydestä VPA:n aiheuttamaan maksavaurioon. POLG1-mutaatioita on pidetty vasta-aiheena maksansiirrolle, mutta tutkimuksessa todettiin homotsygoottisena esiintyvän POLG1-mutaation ja nuoruusiällä tai varhaisella aikuisiällä alkaneen taudin liittyvän parempaan maksansiirron jälkeiseen ennusteeseen. HepG2-solumallilla tehdyt tutkimukset osoittivat VPA:n haittaavan mitokondrioiden solyhengitystä. Tutkimuksen tulokset tuovat lisätietoa mtDNA:n depleetioon ja deleetioihin liittyvistä taudinkuvista ja molekyyligeneettisestä taustasta. POLG1-mutaatiot eivät ole ehdoton vasta-aihe maksansiirrolle; potilaan geneettinen status ja ikä taudin alkamishetkellä vaikuttavat ennusteeseen, mikä tulisi huomioida potilaiden hoidossa. Tulokset myös osoittivat VPA:n olevan mitokondriotoksinen lääke, jonka käyttöä tulisi välttää mitokondriotautipotilaiden hoidossa.
- Published
- 2015
6. Disturbances in mitochondrial DNA maintenance in neuromuscular disorders and valproate-induced liver toxicity
- Author
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Uusimaa, J. (Johanna), Majamaa, K. (Kari), Rantala, H. (Heikki), Komulainen, T. (Tuomas), Uusimaa, J. (Johanna), Majamaa, K. (Kari), Rantala, H. (Heikki), and Komulainen, T. (Tuomas)
- Abstract
Mitochondrial DNA depletion and deletions are related to mutations in the nuclear genes responsible for replication and maintenance of mitochondrial DNA (mtDNA). The POLG1 gene encodes the enzyme responsible for replication of mtDNA. A particular feature of the POLG1 mutations is an increased risk of acute liver failure (ALF) upon exposure to sodium valproate (VPA), but the pathomechanism is not resolved. The present work studies the molecular genetic aetiology and clinical phenotypes associated with mtDNA depletion and deletion. Another objective was an investigation of clinical phenotypes in POLG1 mutations and disentangling the pathomechanism of VPA-induced ALF in POLG1 mutations. Mitochondrial toxicity of VPA was examined using HepG2 cells as an experimental in vitro model. In this work, mtDNA depletion was associated with severe neonatal-onset encephalopathy. Furthermore, mtDNA depletion was found in muscle dystrophy as a secondary finding to muscle degradation. Multiple mitochondrial DNA deletions were found in two patients with Kearns-Sayre syndrome suggesting a genetic origin of the disease. POLG1 p.R722H mutation has been previously reported as a neutral polymorphism, but we found evidence suggesting that POLG1 p.R722H could be a pathogenic mutation in a homozygous or compound heterozygous state. We identified retrospectively five patients, who required liver transplant after VPA-induced ALF. All five patients harboured POLG1 mutations supporting the evidence of POLG1 mutations as a risk factor for VPA-induced ALF. Previously, patients with POLG1 mutations have been considered unsuitable for liver transplantation, but we found that homozygous POLG1 mutations and adolescent or adult-onset disease predicted a good outcome following liver transplantation. In vitro studies on HepG2 cells showed that VPA disturbs mitochondrial respiration. Our results expand the phenotypes and molecular genetic features in mitochondrial DNA depletion and deletion syndro, Tiivistelmä Mitokondrion DNA:n (mtDNA) kahdentumisesta ja ylläpidosta vastaavien tuman geenien mutaatiot voivat johtaa mtDNA:n määrän vähenemiseen (depleetioon) ja katkoksiin (deleetioihin). MtDNA:n kahdentumisesta vastaavaa entsyymiä koodaa tuman POLG1-geeni. POLG1-mutaatioihin liittyy kohonnut riski sairastua natriumvalproaatin (VPA) aiheuttamaan akuuttiin maksavaurioon. Tutkimuksen tavoitteena oli tutkia mtDNA:n depleetion ja deleetioiden molekyyligeneettistä etiologiaa ja kliinisiä taudinkuvia. Tutkimuksessa selvitettiin myös POLG1-mutaatioihin liittyviä taudinkuvia ja POLG1-mutaatioihin liittyvän akuutin maksavaurion patomekanismia. VPA:n vaikutusta mitokondrioiden toimintaan tutkittiin in vitro HepG2-solumallissa. Tutkimuksessa todettiin mtDNA:n depleetion liittyvän vaikeaan varhain alkavaan aivosairauteen. Depleetio todettiin myös sekundaarisena merosiini-negatiivisessa lihasdystrofiassa. Kahdella Kearns-Sayren syndroomaa sairastavalla potilaalla todettiin multippelit mtDNA:n deleetiot, mikä viittaa syndrooman geneettisen alkuperään. POLG1 p.R722H-mutaatiota on aiemmin pidetty neutraalina polymorfiana, mutta tutkimuksen tulokset viittasivat siihen, että homotsygoottisena tai yhdistelmäheterotsygoottisena mutaatio on tautia aiheuttava. Helsingin yliopistollisen sairaalan elinsiirtorekisteristä tunnistettiin retrospektiivisesti viisi potilasta, jotka olivat saaneet maksansiirteen VPA:n aiheuttaman maksavaurion vuoksi. Kaikilla viidellä potilaalla todettiin POLG1-geenin mutaatio, mikä vahvistaa käsitystä geenin yhteydestä VPA:n aiheuttamaan maksavaurioon. POLG1-mutaatioita on pidetty vasta-aiheena maksansiirrolle, mutta tutkimuksessa todettiin homotsygoottisena esiintyvän POLG1-mutaation ja nuoruusiällä tai varhaisella aikuisiällä alkaneen taudin liittyvän parempaan maksansiirron jälkeiseen ennusteeseen. HepG2-solumallilla tehdyt tutkimukset osoittivat VPA:n haittaavan mitokondrioiden solyhengitystä. Tutkimuksen tulokset tuovat lisätietoa mtDNA:n depleetioon ja
- Published
- 2015
7. OP46 – 2969: Novel phenotypes of childhood encephalomyopathies with mitochondrial DNA depletion or deletions
- Author
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Hautakangas, M.R., primary, Komulainen, T., additional, Hinttala, R., additional, Pakanen, S., additional, Vähäsaija, V., additional, Lehenkari, P., additional, Olsen, P., additional, Vieira, P., additional, Saarenpää-Heikkilä, O., additional, Palmio, J., additional, Tuominen, H., additional, Kinnunen, P., additional, Majamaa, K., additional, Rantala, H., additional, and Uusimaa, J., additional
- Published
- 2015
- Full Text
- View/download PDF
8. Myofibroblasts reside in the middle dermis of the keloids but do not predict the response to injection therapies: a double-blinded, randomized, controlled trial.
- Author
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Komulainen T, Daymond P, Hietanen KE, Kaartinen IS, and Järvinen TAH
- Abstract
Introduction: Keloids form as a pathological response to skin wound healing, and their etiopathology is poorly understood. Myofibroblasts, which are cells transformed from normal fibroblasts, are believed to contribute to pathological scar formation in wounds., Methods: We carried out a double-blinded randomized controlled trial (RCT) comparing the efficacy of intralesional 5-fluorouracil (5-FU) and triamcinolone (TAC) injections in treating keloids. A total of 43 patients with 50 keloids were treated with either intralesional TAC or 5-FU injections, and their clinical response was evaluated. Biopsies were collected before, during, and after injection therapy from the active border of a keloid. To understand the role of myofibroblasts in keloids, we conducted an immunohistochemical analysis to identify myofibroblasts [α-smooth muscle actin (αSMA)] from the biopsies. We first defined the three histologically distinct regions-superficial, middle, and deep dermis-in each keloid., Results: We then demonstrated that myofibroblasts almost exclusively exist in the middle dermis of the keloids as 80% of the cells in the middle dermis were αSMA positive. However, both the percentage of myofibroblasts as well as the area covered by them was substantially lower in the superficial and deep dermis than in the middle dermis of the keloids. Myofibroblasts do not predict the clinical response to intralesional injection therapies. There is no difference in the myofibroblast numbers in keloids or in the induced change in myofibroblasts between the responders and non-responders after treatment., Discussion: This study demonstrates that myofibroblasts reside almost exclusively in the middle dermis layer of the keloids, but their numbers do not predict the clinical response to intralesional injection therapies in the RCT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Komulainen, Daymond, Hietanen, Kaartinen and Järvinen.)
- Published
- 2024
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9. Infantile onset encephalomyopathy, retinopathy, optic atrophy, and mitochondrial DNA depletion associated with a novel pathogenic DHX16 variant.
- Author
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Hautakangas MR, Widgren P, Korpelainen P, Kangas SM, Komulainen T, Vieira P, Rahikkala E, Pylkäs K, Tuominen H, Kokkonen H, Miinalainen I, Nadaf J, Majewski J, Hinttala R, and Uusimaa J
- Subjects
- Humans, DNA, Mitochondrial genetics, Muscle, Skeletal pathology, RNA Helicases, Infant, Metabolism, Inborn Errors, Optic Atrophy pathology, Retinal Diseases
- Abstract
We studied a patient with mitochondrial DNA depletion in skeletal muscle and a multiorgan phenotype, including fatal encephalomyopathy, retinopathy, optic atrophy, and sensorineural hearing loss. Instead of pathogenic variants in the mitochondrial maintenance genes, we identified previously unpublished variant in DHX16 gene, a de novo heterozygous c.1360C>T (p. Arg454Trp). Variants in DHX16 encoding for DEAH-box RNA helicase have previously been reported only in five patients with a phenotype called as neuromuscular oculoauditory syndrome including developmental delay, neuromuscular symptoms, and ocular or auditory defects with or without seizures. We performed functional studies on patient-derived fibroblasts and skeletal muscle revealing, that the DHX16 expression was decreased. Clinical features together with functional data suggest, that our patient's disease is associated with a novel pathogenic DHX16 variant, and mtDNA depletion could be a secondary manifestation of the disease., (© 2023 The Authors. Clinical Genetics published by John Wiley & Sons Ltd.)
- Published
- 2023
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10. Incidence and Risk Factors of Transient Global Amnesia.
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Komulainen T, Bärlund V, Tanila H, Koivisto A, and Jäkälä P
- Subjects
- Humans, Incidence, Risk Factors, Water, Amnesia, Transient Global epidemiology, Amnesia, Transient Global complications, Migraine Disorders
- Abstract
Introduction: Transient global amnesia (TGA) is a spontaneously resolving, anterograde amnesia that lasts mostly <24 h and often occurs with retrograde amnesia. The etiology of TGA remains unclear, although in recent decades, many risk factors and preceding events have been identified. There are few up-to-date reports on the TGA incidence in Northern Europe. In this study, we report the incidence and risk factors associated with TGA in Finland., Materials and Methods: The study included all patients with suspected TGA that were referred to Kuopio University Hospital (KUH) in 2017. The hospital catchment area included 246,653 individuals. Risk factors and demographic data were collected from medical records. The TGA incidence rates were calculated as the number of patients with TGA divided by the number of individuals at risk in different age groups., Results: In 2017, 56 patients were treated for TGA at KUH. Of these, 46 had a first-ever TGA. The most common event preceding TGA was physical effort (n = 28, 50%), followed by emotional stress (n = 11, 19.6%) and water contact or a temperature change (n = 11, 19.6%). The most common comorbidities were hypercholesterolemia (n = 22, 39.3%), hypertensive disease (n = 21, 37.5%), hypothyroidism (n = 11, 19.6%), coronary artery disease (n = 8, 14.3%), and migraine (n = 7, 12.5%). TGA occurred most often in December (n = 9, 16.0%), March (n = 8, 14.3%), or October (n = 8, 14.3%), and least often in November and May (n = 2, 3.6% in both months). The crude incidence of a first TGA in Eastern Finland was 18.6/100,000 inhabitants, and when standardized to the European population in 2010, it was 14.3/100,000 inhabitants. Therefore, the TGA incidence was higher than previously reported in European countries., Discussion: The most common precipitating factors for TGA were physical effort, emotional stress, and water contact/temperature change. The incidence of TGA was high in the Eastern Finnish population., (© 2023 The Author(s). Published by S. Karger AG, Basel.)
- Published
- 2023
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11. Incidence of first-ever transient ischemic attack in Eastern Finland.
- Author
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Komulainen T, Koivisto A, and Jäkälä P
- Subjects
- Aged, Female, Finland epidemiology, Humans, Incidence, Male, Neurologic Examination, Ischemic Attack, Transient diagnosis, Ischemic Attack, Transient epidemiology, Stroke epidemiology
- Abstract
Objectives: The incidence of stroke has been declining in Finland, as well as in Europe. However, it is unclear whether the incidence of transient ischemic attack (TIA) is also decreasing. In fact, the TIA incidence in the Finnish population has never been reported. Therefore, here we investigated the incidence of TIA in the Eastern Finnish population in 2017., Materials and Methods: All patients with suspected TIA, from a defined catchment area, were referred to a neurological emergency unit at Kuopio University Hospital (KUH) in the Northern Savonia region of Eastern Finland, which had a population of 246,653 in 2017. The original study population comprised TIA patients diagnosed based on the WHO TIA criteria in 2017. Incidence rates were calculated by dividing the number of TIA cases by the number of people in different age groups., Results: Among 432 patients with a suspected TIA referred to the neurological emergency unit at Kuopio University Hospital in 2017, 293 were living in Northern Savonia and were ultimately diagnosed with TIA after neurological examinations. The number of first-ever TIAs was 211. The crude incidence of all TIA was 122/100,000 inhabitants, and of first-ever TIA was 86/100,000. The age-standardized incidence (European population 2010) of the first-ever TIA was calculated to be 64/100,000. The mean age of first-ever TIA patients was 70 years: 72 years for women versus 68 years for men., Conclusions: We found a high incidence of TIA in Eastern Finland., (© 2022 The Authors. Acta Neurologica Scandinavica published by John Wiley & Sons Ltd.)
- Published
- 2022
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12. A relational database to identify differentially expressed genes in the endometrium and endometriosis lesions.
- Author
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Gabriel M, Fey V, Heinosalo T, Adhikari P, Rytkönen K, Komulainen T, Huhtinen K, Laajala TD, Siitari H, Virkki A, Suvitie P, Kujari H, Aittokallio T, Perheentupa A, and Poutanen M
- Subjects
- Endometrium pathology, Female, Humans, Peritoneum pathology, Endometriosis genetics, Endometrium metabolism, Gene Expression, Peritoneum metabolism
- Abstract
Endometriosis is a common inflammatory estrogen-dependent gynecological disorder, associated with pelvic pain and reduced fertility in women. Several aspects of this disorder and its cellular and molecular etiology remain unresolved. We have analyzed the global gene expression patterns in the endometrium, peritoneum and in endometriosis lesions of endometriosis patients and in the endometrium and peritoneum of healthy women. In this report, we present the EndometDB, an interactive web-based user interface for browsing the gene expression database of collected samples without the need for computational skills. The EndometDB incorporates the expression data from 115 patients and 53 controls, with over 24000 genes and clinical features, such as their age, disease stages, hormonal medication, menstrual cycle phase, and the different endometriosis lesion types. Using the web-tool, the end-user can easily generate various plot outputs and projections, including boxplots, and heatmaps and the generated outputs can be downloaded in pdf-format.Availability and implementationThe web-based user interface is implemented using HTML5, JavaScript, CSS, Plotly and R. It is freely available from https://endometdb.utu.fi/ .
- Published
- 2020
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13. A novel mutation m.8561C>G in MT-ATP6/8 causing a mitochondrial syndrome with ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.
- Author
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Kytövuori L, Lipponen J, Rusanen H, Komulainen T, Martikainen MH, and Majamaa K
- Subjects
- Adenosine Triphosphate metabolism, Ataxia complications, DNA Mutational Analysis, Female, Humans, Hypogonadism complications, Male, Middle Aged, Mitochondrial Diseases complications, Peripheral Nervous System Diseases complications, Ataxia genetics, Hypogonadism genetics, Mitochondrial Diseases genetics, Mitochondrial Proton-Translocating ATPases genetics, Mutation genetics, Peripheral Nervous System Diseases genetics
- Abstract
Defects in the respiratory chain or mitochondrial ATP synthase (complex V) result in mitochondrial dysfunction that is an important cause of inherited neurological disease. Two of the subunits of complex V are encoded by MT-ATP6 and MT-ATP8 in the mitochondrial genome. Pathogenic mutations in MT-ATP6 are associated with the Leigh syndrome, the syndrome of neuropathy, ataxia, and retinitis pigmentosa (NARP), as well as with non-classical phenotypes, while MT-ATP8 is less frequently mutated in patients with mitochondrial disease. We investigated two adult siblings presenting with features of cerebellar ataxia, peripheral neuropathy, diabetes mellitus, sensorineural hearing impairment, and hypergonadotropic hypogonadism. As the phenotype was suggestive of mitochondrial disease, mitochondrial DNA was sequenced and a novel heteroplasmic mutation m.8561C>G in the overlapping region of the MT-ATP6 and MT-ATP8 was found. The mutation changed amino acids in both subunits. Mutation heteroplasmy correlated with the disease phenotype in five family members. An additional assembly intermediate of complex V and increased amount of subcomplex F
1 were observed in myoblasts of the two patients, but the total amount of complex V was unaffected. Furthermore, intracellular ATP concentration was lower in patient myoblasts indicating defective energy production. We suggest that the m.8561C>G mutation in MT-ATP6/8 is pathogenic, leads biochemically to impaired assembly and decreased ATP production of complex V, and results clinically in a phenotype with the core features of cerebellar ataxia, peripheral neuropathy, diabetes mellitus, and hypergonadotropic hypogonadism.- Published
- 2016
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14. Sodium valproate induces mitochondrial respiration dysfunction in HepG2 in vitro cell model.
- Author
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Komulainen T, Lodge T, Hinttala R, Bolszak M, Pietilä M, Koivunen P, Hakkola J, Poulton J, Morten KJ, and Uusimaa J
- Subjects
- Adenosine Triphosphate metabolism, Cell Death drug effects, Cell Proliferation drug effects, Cell Respiration drug effects, Chemical and Drug Induced Liver Injury metabolism, Chemical and Drug Induced Liver Injury pathology, Dose-Response Relationship, Drug, Electron Transport Chain Complex Proteins metabolism, Galactose metabolism, Glucose metabolism, Hep G2 Cells, Hepatocytes metabolism, Hepatocytes pathology, Humans, Membrane Potential, Mitochondrial drug effects, Mitochondria, Liver metabolism, Mitochondria, Liver pathology, Mitochondrial Diseases metabolism, Mitochondrial Diseases pathology, Oxidative Stress drug effects, Pyruvic Acid metabolism, Reactive Oxygen Species metabolism, Superoxide Dismutase metabolism, Time Factors, Anticonvulsants toxicity, Chemical and Drug Induced Liver Injury etiology, Hepatocytes drug effects, Mitochondria, Liver drug effects, Mitochondrial Diseases chemically induced, Oxidative Phosphorylation drug effects, Valproic Acid toxicity
- Abstract
Sodium valproate (VPA) is a potentially hepatotoxic antiepileptic drug. Risk of VPA-induced hepatotoxicity is increased in patients with mitochondrial diseases and especially in patients with POLG1 gene mutations. We used a HepG2 cell in vitro model to investigate the effect of VPA on mitochondrial activity. Cells were incubated in glucose medium and mitochondrial respiration-inducing medium supplemented with galactose and pyruvate. VPA treatments were carried out at concentrations of 0-2.0mM for 24-72 h. In both media, VPA caused decrease in oxygen consumption rates and mitochondrial membrane potential. VPA exposure led to depleted ATP levels in HepG2 cells incubated in galactose medium suggesting dysfunction in mitochondrial ATP production. In addition, VPA exposure for 72 h increased levels of mitochondrial reactive oxygen species (ROS), but adversely decreased protein levels of mitochondrial superoxide dismutase SOD2, suggesting oxidative stress caused by impaired elimination of mitochondrial ROS and a novel pathomechanism related to VPA toxicity. Increased cell death and decrease in cell number was detected under both metabolic conditions. However, immunoblotting did not show any changes in the protein levels of the catalytic subunit A of mitochondrial DNA polymerase γ, the mitochondrial respiratory chain complexes I, II and IV, ATP synthase, E3 subunit dihydrolipoyl dehydrogenase of pyruvate dehydrogenase, 2-oxoglutarate dehydrogenase and glutathione peroxidase. Our results show that VPA inhibits mitochondrial respiration and leads to mitochondrial dysfunction, oxidative stress and increased cell death, thus suggesting an essential role of mitochondria in VPA-induced hepatotoxicity., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2015
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15. Mitochondrial DNA Depletion and Deletions in Paediatric Patients with Neuromuscular Diseases: Novel Phenotypes.
- Author
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Komulainen T, Hautakangas MR, Hinttala R, Pakanen S, Vähäsarja V, Lehenkari P, Olsen P, Vieira P, Saarenpää-Heikkilä O, Palmio J, Tuominen H, Kinnunen P, Majamaa K, Rantala H, and Uusimaa J
- Abstract
Objective: To study the clinical manifestations and occurrence of mtDNA depletion and deletions in paediatric patients with neuromuscular diseases and to identify novel clinical phenotypes associated with mtDNA depletion or deletions., Methods: Muscle DNA samples from patients presenting with undefined encephalomyopathies or myopathies were analysed for mtDNA content by quantitative real-time PCR and for deletions by long-range PCR. Direct sequencing of mtDNA maintenance genes and whole-exome sequencing were used to study the genetic aetiologies of the diseases. Clinical and laboratory findings were collected., Results: Muscle samples were obtained from 104 paediatric patients with neuromuscular diseases. mtDNA depletion was found in three patients with severe early-onset encephalomyopathy or myopathy. Two of these patients presented with novel types of mitochondrial DNA depletion syndromes associated with increased serum creatine kinase (CK) and multiorgan disease without mutations in any of the known mtDNA maintenance genes; one patient had pathologic endoplasmic reticulum (ER) membranes in muscle. The third patient with mtDNA depletion was diagnosed with merosine-deficient muscular dystrophy caused by a homozygous mutation in the LAMA2 gene. Two patients with an early-onset Kearns-Sayre/Pearson-like phenotype harboured a large-scale mtDNA deletion, minor multiple deletions and high mtDNA content., Conclusions: Novel encephalomyopathic mtDNA depletion syndrome with structural alterations in muscle ER was identified. mtDNA depletion may also refer to secondary mitochondrial changes related to muscular dystrophy. We suggest that a large-scale mtDNA deletion, minor multiple deletions and high mtDNA content associated with Kearns-Sayre/Pearson syndromes may be secondary changes caused by mutations in an unknown nuclear gene.
- Published
- 2015
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