Browsing by Subject "DEFECTS"

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  • Ainola, Mari; Tomaszewski, Waclaw; Ostrowska, Barbara; Wesolowska, Ewa; Wagner, H. Daniel; Swieszkowski, Wojciech; Sillat, Tarvo; Peltola, Emilia; Konttinen, Yrjo T. (2016)
    The aim was to develop a hybrid three-dimensional-tissue engineering construct for chondrogenesis. The hypothesis was that they support chondrogenesis. A biodegradable, highly porous polycaprolactone-grate was produced by solid freeform fabrication. The polycaprolactone support was coated with a chitosan/polyethylene oxide nanofibre sheet produced by electrospinning. Transforming growth factor-3-induced chondrogenesis was followed using the following markers: sex determining region Y/-box 9, runt-related transcription factor 2 and collagen II and X in quantitative real-time polymerase chain reaction, histology and immunostaining. A polycaprolactone-grate and an optimized chitosan/polyethylene oxide nanofibre sheet supported cellular aggregation, chondrogenesis and matrix formation. In tissue engineering constructs, the sheets were seeded first with mesenchymal stem cells and then piled up according to the lasagne principle. The advantages of such a construct are (1) the cells do not need to migrate to the tissue engineering construct and therefore pore size and interconnectivity problems are omitted and (2) the cell-tight nanofibre sheet and collagen-fibre network mimic a cell culture platform for mesenchymal stem cells/chondrocytes (preventing escape) and hinders in-growth of fibroblasts and fibrous scarring (preventing capture). This allows time for the slowly progressing, multiphase true cartilage regeneration.
  • Khanam, Afrina; Vohra, Anurag; Slotte, Jonatan; Makkonen, Ilja; Loo, Roger; Pourtois, Geoffrey; Vandervorst, Wilfried (2020)
    Positron annihilation spectroscopy in the Doppler and coincidence Doppler mode was applied on Ge1 xSnx epitaxial layers, grown by chemical vapor deposition with different total As concentrations (1019-1021 cm3), high active As concentrations (1019 cm3), and similar Sn concentrations (5.9%-6.4%). Positron traps are identified as mono-vacancy complexes. Vacancy-As complexes, V-Asi, formed during the growth were studied to deepen the understanding of the electrical passivation of the Ge1 xSnx:As epilayers. Larger monovacancy complexes, V-Asi (i 2), are formed as the As doping increases. The total As concentration shows a significant impact on the saturation of the number of As atoms (i 1/4 4) around the vacancies in the sample epilayers. The presence of V-Asi complexes decreases the dopant activation in the Ge1 xSnx:As epilayers. Furthermore, the presence of Sn failed to hinder the formation of larger V-Asi complexes and thus failed to reduce the donor-deactivation.
  • Esterhuizen, Karien; Lindeque, J. Zander; Mason, Shayne; van der Westhuizen, Francois H.; Suomalainen, Anu; Hakonen, Anna H.; Carroll, Christopher J.; Rodenburg, Richard J.; de Laat, Paul B.; Janssen, Mirian C. H.; Smeitink, Jan A. M.; Louw, Roan (2019)
    We used a comprehensive metabolomics approach to study the altered urinary metabolome of two mitochondrial myopathy, encephalopathy lactic acidosis and stroke like episodes (MELAS) cohorts carrying the m.3243A > G mutation. The first cohort were used in an exploratory phase, identifying 36 metabolites that were significantly perturbed by the disease. During the second phase, the 36 selected metabolites were able to separate a validation cohort of MELAS patients completely from their respective control group, suggesting usefulness of these 36 markers as a diagnostic set. Many of the 36 perturbed metabolites could be linked to an altered redox state, fatty acid catabolism and one-carbon metabolism. However, our evidence indicates that, of all the metabolic perturbations caused by MELAS, stalled fatty acid oxidation prevailed as being particularly disturbed. The strength of our study was the utilization of five different analytical platforms to generate the robust metabolomics data reported here. We show that urine may be a useful source for disease-specific metabolomics data, linking, amongst others, altered one-carbon metabolism to MELAS. The results reported here are important in our understanding of MELAS and might lead to better treatment options for the disease.
  • Vakkilainen, Svetlana; Mäkitie, Riikka; Klemetti, Paula; Valta, Helena; Taskinen, Mervi; Husebye, Eystein Sverre; Mäkitie, Outi (2018)
    Background: Mutations in RMRP, encoding a non-coding RNA molecule, underlie cartilage-hair hypoplasia (CHH), a syndromic immunodeficiency with multiple pathogenetic mechanisms and variable phenotype. Allergy and asthma have been reported in the CHH population and some patients suffer from autoimmune (AI) diseases. Objective: We explored AI and allergic manifestations in a large cohort of Finnish patients with CHH and correlated clinical features with laboratory parameters and autoantibodies. Methods: We collected clinical and laboratory data from patient interviews and hospital records. Serum samples were tested for a range of autoantibodies including celiac, anti-cytokine, and anti-21-hydroxylase antibodies. Nasal cytology samples were analyzed with microscopy. Results: The study cohort included 104 patients with genetically confirmed CHH; their median age was 39.2 years (range 0.6-73.6). Clinical autoimmunity was common (11/104, 10.6%) and included conditions previously undescribed in subjects with CHH (narcolepsy, psoriasis, idiopathic thrombocytopenic purpura, and multifocal motor axonal neuropathy). Patients with autoimmunity more often had recurrent pneumonia, sepsis, high immunoglobulin (Ig) E and/or undetectable IgA levels. The mortality rates were higher in subjects with AI diseases (X-(2)(2) = 14.056, p = 0.0002). Several patients demonstrated serum autoantibody positivity without compatible symptoms. We confirmed the high prevalence of asthma (23%) and allergic rhinoconjunctivitis (39%). Gastrointestinal complaints, mostly persistent diarrhea, were also frequently reported (32/104, 31%). Despite the history of allergic rhinitis, no eosinophils were observed in nasal cytology in five tested patients. Conclusions: AI diseases are common in Finnish patients with CHH and are associated with higher mortality, recurrent pneumonia, sepsis, high IgE and/or undetectable IgA levels. Serum positivity for some autoantibodies was not associated with clinical autoimmunity. The high prevalence of persistent diarrhea, asthma, and symptoms of inflammation of nasal mucosa may indicate common pathways of immune dysregulation.
  • Giordano, Luca; Farnham, Antoine; Dhandapani, Praveen K.; Salminen, Laura; Bhaskaran, Jahnavi; Voswinckel, Robert; Rauschkolb, Peter; Scheibe, Susan; Sommer, Natascha; Beisswenger, Christoph; Weissmann, Norbert; Braun, Thomas; Jacobs, Howard T.; Bals, Robert; Herr, Christian; Szibor, Marten (2019)
    Cigarette smoke (CS) exposure is the predominant risk factor for the development of chronic obstructive pulmonary disease (COPD) and the third leading cause of death worldwide. We aimed to elucidate whether mitochondrial respiratory inhibition and oxidative stress are triggers in its etiology. In different models of CS exposure, we investigated the effect on lung remodeling and cell signaling of restoring mitochondrial respiratory electron flow using alternative oxidase (AOX), which bypasses the cytochrome segment of the respiratory chain. AOX attenuated CS-induced lung tissue destruction and loss of function in mice exposed chronically to CS for 9 months. It preserved the cell viability of isolated mouse embryonic fibroblasts treated with CS condensate, limited the induction of apoptosis, and decreased the production of reactive oxygen species (ROS). In contrast, the early-phase inflammatory response induced by acute CS exposure of mouse lung, i.e., infiltration by macrophages and neutrophils and adverse signaling, was unaffected. The use of AOX allowed us to obtain novel pathomechanistic insights into CS-induced cell damage, mitochondrial ROS production, and lung remodeling. Our findings implicate mitochondrial respiratory inhibition as a key pathogenic mechanism of CS toxicity in the lung. We propose AOX as a novel tool to study CS-related lung remodeling and potentially to counteract CS-induced ROS production and cell damage.
  • Rajendran, Jayasimman; Purhonen, Janne; Tegelberg, Saara; Smolander, Olli-Pekka; Mörgelin, Matthias; Rozman, Jan; Gailus-Durner, Valerie; Fuchs, Helmut; de Angelis, Martin Hrabe; Auvinen, Petri; Mervaala, Eero; Jacobs, Howard T.; Szibor, Marten; Fellman, Vineta; Kallijärvi, Jukka (2019)
    Alternative oxidase (AOX) is a non-mammalian enzyme that can bypass blockade of the complex III-IV segment of the respiratory chain (RC). We crossed a Ciona intestinalis AOX transgene into RC complex III (cIII)-deficient Bcs1l(p.S78G) knock-in mice, displaying multiple visceral manifestations and premature death. The homozygotes expressing AOX were viable, and their median survival was extended from 210 to 590 days due to permanent prevention of lethal cardiomyopathy. AOX also prevented renal tubular atrophy and cerebral astrogliosis, but not liver disease, growth restriction, or lipodystrophy, suggesting distinct tissue-specific pathogenetic mechanisms. Assessment of reactive oxygen species (ROS) production and damage suggested that ROS were not instrumental in the rescue. Cardiac mitochondrial ultrastructure, mitochondrial respiration, and pathological transcriptome and metabolome alterations were essentially normalized by AOX, showing that the restored electron flow upstream of cIII was sufficient to prevent cardiac energetic crisis and detrimental decompensation. These findings demonstrate the value of AOX, both as a mechanistic tool and a potential therapeutic strategy, for cIII deficiencies.
  • Paatela, Teemu; Vasara, Anna; Nurmi, Heikki; Kautiainen, Hannu; Kiviranta, Ilkka (2020)
    The International Cartilage Repair Society (ICRS) score and the Oswestry Arthroscopic Score (OAS) have been validated to evaluate repair tissue quality. However, the performance of these scores has not been studied in typical patients undergoing cartilage repair and who have lesions of varying sizes. In this study, we compared the performance of the ICRS and the OAS scores and analyzed the effect of lesion characteristics on the performance of these two scores. Cartilage repair quality was assessed in a total of 104 arthroscopic observations of cartilage repair sites of the knee in 62 patients after autologous chondrocyte implantation. Two observers scored the repair areas independently with the ICRS and the OAS scores. The performance of both scores was evaluated according to internal consistency and inter-rater reliability and correlation between the scores. The frequency and proportion of disagreements were analyzed according to the repair site area and the given score. The correlation between the scores was good (r = 0.91, 95% confidence interval [CI]: 0.87-0.94). Both scores showed moderate internal consistency and inter-rater reliability. Cronbach's alpha was 0.88 (95% CI: 0.80-0.92) for the ICRS score and 0.79 (95% CI: 0.70-0.86) for the OAS score. The intraclass correlation coefficient was 0.89 (95% CI: 0.84-0.92) for the ICRS and 0.81 (95% CI: 0.74-0.87) for the OAS scores. The frequency and proportion of disagreements were higher in larger repair sites. In arthroscopic use, both ICRS and OAS scores perform similarly, however, their reliability deteriorates as the lesion size increases. (c) 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
  • Mason, D. R.; Sand, A. E.; Dudarev, S. L. (2019)
    We describe the development of a new object kinetic Monte Carlo (kMC) code where the elementary defect objects are off-lattice atomistic configurations. Atomic-level transitions are used to transform and translate objects, to split objects and to merge them together. This gradually constructs a database of atomic configurations-a set of relevant defect objects and their possible events generated on-the-fly. Elastic interactions are handled within objects with empirical potentials at short distances, and between spatially distinct objects using the dipole tensor formalism. The model is shown to evolve mobile interstitial clusters in tungsten faster than an equivalent molecular dynamics (MD) simulation, even at elevated temperatures. We apply the model to the evolution of complex defects generated using MD simulations of primary radiation damage in tungsten. We show that we can evolve defect structures formed in cascade simulations to experimentally observable timescales of seconds while retaining atomistic detail. We conclude that the first few nanoseconds of simulation following cascade initiation would be better performed using MD, as this will capture some of the near-temperature-independent evolution of small highly-mobile interstitial clusters. For the 20keV cascade annealing simulations considered here, we observe internal relaxations of sessile objects. These relaxations would be difficult to capture using conventional object kMC, yet are important as they establish the conditions for long timescale evolution.
  • Rahikkala, Elisa; Myllykoski, Matti; Hinttala, Reetta; Vieira, Paivi; Nayebzadeh, Naemeh; Weiss, Simone; Plomp, Astrid S.; Bittner, Reginald E.; Kurki, Mitja I.; Kuismin, Outi; Lewis, Andrea M.; Väisänen, Marja-Leena; Kokkonen, Hannaleena; Westermann, Jonne; Bernert, Gunther; Tuominen, Hannu; Palotie, Aarno; Aaltonen, Lauri; Yang, Yaping; Potocki, Lorraine; Moilanen, Jukka; van Koningsbruggen, Silvana; Wang, Xia; Schmidt, Wolfgang M.; Koivunen, Peppi; Uusimaa, Johanna (2019)
    Purpose: A new syndrome with hypotonia, intellectual disability, and eye abnormalities (HIDEA) was previously described in a large consanguineous family. Linkage analysis identified the recessive disease locus, and genome sequencing yielded three candidate genes with potentially pathogenic biallelic variants: transketolase (TKT), transmembrane prolyl 4-hydroxylase (P4HTM), and ubiquitin specific peptidase 4 (USP4). However, the causative gene remained elusive. Methods: International collaboration and exome sequencing were used to identify new patients with HIDEA and biallelic, potentially pathogenic, P4HTM variants. Segregation analysis was performed using Sanger sequencing. P4H-TM wild-type and variant constructs without the transmembrane region were overexpressed in insect cells and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot. Results: Five different homozygous or compound heterozygous pathogenic P4HTM gene variants were identified in six new and six previously published patients presenting with HIDEA. Hypoventilation, obstructive and central sleep apnea, and dysautonomia were identified as novel features associated with the phenotype. Characterization of three of the P4H-TM variants demonstrated yielding insoluble protein products and, thus, loss-of-function. Conclusions: Biallelic loss-of-function P4HTM variants were shown to cause HIDEA syndrome. Our findings enable diagnosis of the condition, and highlight the importance of assessing the need for noninvasive ventilatory support in patients.
  • Szibor, Marten; Dhandapani, Praveen K.; Dufour, Eric; Holmstrom, Kira M.; Zhuang, Yuan; Salwig, Isabelle; Wittig, Ilka; Heidler, Juliana; Gizatullina, Zemfira; Gainutdinov, Timur; Fuchs, Helmut; Gailus-Durner, Valerie; de Angelis, Martin Hrabe; Nandania, Jatin; Velagapudi, Vidya; Wietelmann, Astrid; Rustin, Pierre; Gellerich, Frank N.; Jacobs, Howard T.; Braun, Thomas; German Mouse Clinic Consortium (2017)
    Plants and many lower organisms, but not mammals, express alternative oxidases (AOXs) that branch the mitochondrial respiratory chain, transferring electrons directly from ubiquinol to oxygen without proton pumping. Thus, they maintain electron flow under conditions when the classical respiratory chain is impaired, limiting excess production of oxygen radicals and supporting redox and metabolic homeostasis. AOX from Ciona intestinalis has been used to study and mitigate mitochondrial impairments in mammalian cell lines, Drosophila disease models and, most recently, in the mouse, where multiple lentivector-AOX transgenes conferred substantial expression in specific tissues. Here, we describe a genetically tractable mouse model in which Ciona AOX has been targeted to the Rosa26 locus for ubiquitous expression. The AOX(Rosa26) mouse exhibited only subtle phenotypic effects on respiratory complex formation, oxygen consumption or the global metabolome, and showed an essentially normal physiology. AOX conferred robust resistance to inhibitors of the respiratory chain in organello; moreover, animals exposed to a systemically applied LD50 dose of cyanide did not succumb. The AOX(Rosa26) mouse is a useful tool to investigate respiratory control mechanisms and to decipher mitochondrial disease aetiology in vivo.
  • Hytönen, Marjo K.; Arumilli, Meharji; Sarkiala, Eva; Nieminen, Pekka; Lohi, Hannes (2019)
    Amelogenesis imperfecta (AI) refers to a genetically and clinically heterogeneous group of inherited disorders affecting the structure, composition, and quantity of tooth enamel. Both non-syndromic and syndromic forms of AI have been described and several genes affecting various aspects of the enamel physiology have been reported. Genetically modified murine models of various genes have provided insights into the complex regulation of proper amelogenesis. Non-syndromic AI occurs spontaneously also in dogs with known recessive variants in ENAM and SLC24A4 genes. Unlike rodents with a reduced dentition and continuously erupting incisors, canine models are valuable for human AI due to similarity in the dental anatomy including deciduous and permanent teeth. We have performed a series of clinical and genetic analyses to investigate AI in several breeds of dogs and describe here two novel recessive variants in the ENAM and ACP4 genes. A fully segregating missense variant (c.716C>T) in exon 8 of ENAM substitutes a well-conserved proline to leucine, p.(Pro239Leu), resulting in a clinical hypomineralization of teeth. A 1-bp insertion in ACP4 (c.1189dupG) is predicted to lead to a frameshift, p.(Ala397Glyfs), resulting in an abnormal C-terminal part of the protein, and hypoplastic AI. The ENAM variant was specific for Parson Russell Terriers with a carrier frequency of 9%. The ACP4 variant was found in two breeds, Akita and American Akita with a carrier frequency of 22%. These genetic findings establish novel canine models of human AI with a particular interest in the case of the ACP4-deficient model, since ACP4 physiology is poorly characterized in human AI. The affected dogs could also serve as preclinical models for novel treatments while the breeds would benefit from genetic tests devised here for veterinary diagnostics and breeding programs.
  • Sand, A. E.; Mason, D. R.; De Backer, A.; Yi, X.; Dudarev, S. L.; Nordlund, K. (2017)
    The sizes of defect clusters, produced in materials by energetic ion or neutron impacts, are critically important input for models describing microstructural evolution of irradiated materials. We propose a model for the distribution of sizes of vacancy and self-interstitial defect clusters formed by high-energy impacts in tungsten, and provide new data from in situ ion irradiation experiments to validate the model. The model predicts the statistics of sub-cascade splitting and the resulting distribution of primary defects extending over the entire range of cluster sizes, and is able to provide initial conditions for quantitative multi-scale simulations of microstructural evolution. [GRAPHICS] .
  • Salonius, Eve; Kontturi, Leena; Laitinen, Anita; Haaparanta, Anne-Marie; Korhonen, Matti; Nystedt, Johanna; Kiviranta, Ilkka; Muhonen, Virpi (2020)
    Cell therapy combined with biomaterial scaffolds is used to treat cartilage defects. We hypothesized that chondrogenic differentiation bone marrow-derived mesenchymal stem cells (BM-MSCs) in three-dimensional biomaterial scaffolds would initiate cartilaginous matrix deposition and prepare the construct for cartilage regeneration in situ. The chondrogenic capability of human BM-MSCs was first verified in a pellet culture. The BM-MSCs were then either seeded onto a composite scaffold rhCo-PLA combining polylactide and collagen type II (C2) or type III (C3), or commercial collagen type I/III membrane (CG). The BM-MSCs were either cultured in a proliferation medium or chondrogenic culture medium. Adult human chondrocytes (ACs) served as controls. After 3, 14, and 28 days, the constructs were analyzed with quantitative polymerase chain reaction and confocal microscopy and sulfated glycosaminoglycans (GAGs) were measured. The differentiated BM-MSCs entered a hypertrophic state by Day 14 of culture. The ACs showed dedifferentiation with no expression of chondrogenic genes and low amount of GAG. The CG membrane induced the highest expression levels of hypertrophic genes. The two different collagen types in composite scaffolds yielded similar results. Regardless of the biomaterial scaffold, culturing BM-MSCs in chondrogenic differentiation medium resulted in chondrocyte hypertrophy. Thus, caution for cell fate is required when designing cell-biomaterial constructs for cartilage regeneration.
  • Raissadati, Alireza; Haukka, Jari; Pätilä, Tommi; Nieminen, Heta; Jokinen, Eero (2020)
    Background Postoperative morbidity is an increasingly important outcome measure of patients who have undergone congenital heart surgery (CHS). We examined late postoperative morbidity after CHS on the basis of patients' government-issued medical special reimbursement rights. Methods and Results Between 1953 and 2009, 10 635 patients underwent CHS at Conclusions Chronic cardiac and noncardiac sequelae are common after CHS regardless of the severity of the defect, underscoring the importance of long-term follow-up of all patients after CHS.
  • Kiiski, Juha; Kuokkanen, Hannu O.; Kääriäinen, Minna; Kaartinen, Ilkka S.; Pakarinen, Toni-Karri; Laitinen, Minna K. (2018)
    Background: Sacrectomy is a rare and demanding surgical procedure that results in major soft tissue defects and spinopelvic discontinuity. No consensus is available on the optimal reconstruction algorithm. Therefore, the present study evaluated the results of sacrectomy reconstruction and its impact on patients' quality of life (QOL). Methods: A retrospective chart review was conducted for 21 patients who underwent sacrectomy for a primary bone tumour. Patients were divided into groups based on the timing of reconstruction as follows: no reconstruction, immediate reconstruction or delayed reconstruction. QOL was measured using the EQ-5D instrument before and after surgery in patients treated in the intensive care unit. Results: The mean patient age was 57 (range 22-81) years. The most common reconstruction was gluteal muscle flap (n =9) and gluteal fasciocutaneous flap (n = 4). Four patients required free-tissue transfer, three latissimus dorsi flaps and one vascular fibula bone transfer. No free flap losses were noted. The need for unplanned re-operations did not differ between groups (p =0.397), and no significant differences were found for pre- and post-operative QOL or any of its dimensions. Discussion: Free flap surgery is reliable for reconstructing the largest sacrectomy defects. Even in the most complex cases, surgery can be safely staged, and final reconstruction can be carried out within 1 week of resection surgery without increasing peri-operative complications. Sacrectomy does not have an immoderate effect on the measured QOL. (C) 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
  • Kotilainen, Hannele; Lokki, Marja-Liisa; Paakkanen, Riitta; Seppanen, Mikko; Tukiainen, Pentti; Meri, Seppo; Poussa, Tuija; Eskola, Jussi; Valtonen, Ville; Jarvinen, Asko (2014)
  • Känsäkoski, Johanna; Jaaskelainen, Jarmo; Jaaskelainen, Tiina; Tommiska, Johanna; Saarinen, Lilli; Lehtonen, Rainer; Hautaniemi, Sampsa; Frilander, Mikko J.; Palvimo, Jorma J.; Toppari, Jorma; Raivio, Taneli (2016)
    Mutations in the X-linked androgen receptor (AR) gene underlie complete androgen insensitivity syndrome (CAIS), the most common cause of 46, XY sex reversal. Molecular genetic diagnosis of CAIS, however, remains uncertain in patients who show normal coding region of AR. Here, we describe a novel mechanism of AR disruption leading to CAIS in two 46, XY sisters. We analyzed whole-genome sequencing data of the patients for pathogenic variants outside the AR coding region. Patient fibroblasts from the genital area were used for AR cDNA analysis and protein quantification. Analysis of the cDNA revealed aberrant splicing of the mRNA caused by a deep intronic mutation (c.2450-118A>G) in the intron 6 of AR. The mutation creates a de novo 5' splice site and a putative exonic splicing enhancer motif, which leads to the preferential formation of two aberrantly spliced mRNAs (predicted to include a premature stop codon). Patient fibroblasts contained no detectable AR protein. Our results show that patients with CAIS and normal AR coding region need to be examined for deep intronic mutations that can lead to pseudoexon activation.
  • Buchs, Gilles; Krasheninnikov, Arkady V.; Ruffieux, Pascal; Groening, Pierangelo; Foster, Adam S.; Nieminen, Risto M.; Groening, Oliver (2007)
  • Taleb, Kawther; Lauridsen, Eva; Daugaard-Jensen, Jette; Nieminen, Pekka; Kreiborg, Sven (2018)
    BackgroundDentinogenesis imperfecta (DI) is a rare debilitating hereditary disorder affecting dentin formation and causing loss of the overlying enamel. Clinically, DI sufferers have a discolored and weakened dentition with an increased risk of fracture. The aims of this study were to assess genotype-phenotype findings in three families with DI-II with special reference to mutations in the DSPP gene and clinical, histological, and imaging manifestations. MethodsNine patients participated in the study (two from family A, four from family B, and three from family C). Buccal swab samples were collected from all participants and extracted for genomic DNA. Clinical and radiographic examinations had been performed longitudinally, and the dental status was documented using photographic images. Four extracted and decalcified tooth samples were prepared for histological analysis to assess dysplastic manifestations in the dentin. Optical coherence tomography (OCT) was applied to study the health of enamel tissue from invivo images and the effect of the mutation on the function and structure of the DSPP gene was analyzed using bioinformatics software programs. ResultsThe direct DNA sequence analysis revealed three distinct mutations, one of which was a novel finding. The mutations caused dominant phenotypes presumably by interference with signal peptide processing and protein secretion. The clinical and radiographic disturbances in the permanent dentition indicated interfamilial variability in DI-II manifestations, however, no significant intrafamilial variability was observed. ConclusionThe different mutations in the DSPP gene were accompanied by distinct phenotypes. Enamel defects suggested deficit in preameloblast function during the early stages of amelogenesis.
  • Andjelkovic, Ana; Oliveira, Marcos T.; Cannino, Giuseppe; Yalgin, Cagri; Dhandapani, Praveen K.; Dufour, Eric; Rustin, Pierre; Szibor, Marten; Jacobs, Howard T. (2015)
    The mitochondrial alternative oxidase, AOX, carries out the non proton-motive re-oxidation of ubiquinol by oxygen in lower eukaryotes, plants and some animals. Here we created a modified version of AOX from Ciona instestinalis, carrying mutations at conserved residues predicted to be required for chelation of the diiron prosthetic group. The modified protein was stably expressed in mammalian cells or flies, but lacked enzymatic activity and was unable to rescue the phenotypes of flies knocked down for a subunit of cytochrome oxidase. The mutated AOX transgene is thus a potentially useful tool in studies of the physiological effects of AOX expression.