939 resultados para Model of curriculum development
Resumo:
In human, neuronal migration disorders are commonly associated with developmental delay, mental retardation, and epilepsy. We describe here a new mouse mutant that develops a heterotopic cortex (HeCo) lying in the dorsolateral hemispheric region, between the homotopic cortex (HoCo) and subcortical white matter. Cross-breeding demonstrated an autosomal recessive transmission. Birthdating studies and immunochemistry for layer-specific markers revealed that HeCo formation was due to a transit problem in the intermediate zone affecting both radially and tangentially migrating neurons. The scaffold of radial glial fibers, as well as the expression of doublecortin is not altered in the mutant. Neurons within the HeCo are generated at a late embryonic age (E18) and the superficial layers of the HoCo have a correspondingly lower cell density and layer thickness. Parvalbumin immunohistochemistry showed the presence of gamma-aminobutyric acidergic cells in the HeCo and the mutant mice have a lowered threshold for the induction of epileptic seizures. The mutant showed a developmental delay but, in contrast, memory function was relatively spared. Therefore, this unique mouse model resembles subcortical band heterotopia observed in human. This model represents a new and rare tool to better understand cortical development and to investigate future therapeutic strategies for refractory epilepsy.
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Large animal models are an important resource for the understanding of human disease and for evaluating the applicability of new therapies to human patients. For many diseases, such as cone dystrophy, research effort is hampered by the lack of such models. Lentiviral transgenesis is a methodology broadly applicable to animals from many different species. When conjugated to the expression of a dominant mutant protein, this technology offers an attractive approach to generate new large animal models in a heterogeneous background. We adopted this strategy to mimic the phenotype diversity encounter in humans and generate a cohort of pigs for cone dystrophy by expressing a dominant mutant allele of the guanylate cyclase 2D (GUCY2D) gene. Sixty percent of the piglets were transgenic, with mutant GUCY2D mRNA detected in the retina of all animals tested. Functional impairment of vision was observed among the transgenic pigs at 3 months of age, with a follow-up at 1 year indicating a subsequent slower progression of phenotype. Abnormal retina morphology, notably among the cone photoreceptor cell population, was observed exclusively amongst the transgenic animals. Of particular note, these transgenic animals were characterized by a range in the severity of the phenotype, reflecting the human clinical situation. We demonstrate that a transgenic approach using lentiviral vectors offers a powerful tool for large animal model development. Not only is the efficiency of transgenesis higher than conventional transgenic methodology but this technique also produces a heterogeneous cohort of transgenic animals that mimics the genetic variation encountered in human patients.
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One third of all stroke survivors develop post-stroke depression (PSD). Depressive symptoms adversely affect rehabilitation and significantly increase risk of death in the post-stroke period. One of the theoretical views on the determinants of PSD focuses on psychosocial factors like disability and social support. Others emphasize biologic mechanisms such as disruption of biogenic amine neurotransmission and release of proinflammatory cytokines. The "lesion location" perspective attempts to establish a relationship between localization of stroke and occurrence of depression, but empirical results remain contradictory. These divergences are partly related to the fact that neuroimaging methods, unlike neuropathology, are not able to assess precisely the full extent of stroke-affected areas and do not specify the different types of vascular lesions. We provide here an overview of the known phenomenological profile and current pathogenic hypotheses of PSD and present neuropathological data challenging the classic "single-stroke"-based neuroanatomical model of PSD. We suggest that vascular burden due to the chronic accumulation of small macrovascular and microvascular lesions may be a crucial determinant of the development and evolution of PSD.
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Machado-Joseph disease or Spinocerebellar ataxia type 3 is a progressive fatal neurodegenerative disorder caused by the polyglutamine-expanded protein ataxin-3. Recent studies demonstrate that RNA interference is a promising approach for the treatment of Machado-Joseph disease. However, whether gene silencing at an early time-point is able to prevent the appearance of motor behavior deficits typical of the disease when initiated before onset of the disease had not been explored. Here, using a lentiviral-mediated allele-specific silencing of mutant ataxin-3 in an early pre-symptomatic cerebellar mouse model of Machado-Joseph disease we show that this strategy hampers the development of the motor and neuropathological phenotypic characteristics of the disease. At the histological level, the RNA-specific silencing of mutant ataxin-3 decreased formation of mutant ataxin-3 aggregates, preserved Purkinje cell morphology and expression of neuronal markers while reducing cell death. Importantly, gene silencing prevented the development of impairments in balance, motor coordination, gait and hyperactivity observed in control mice. These data support the therapeutic potential of RNA interference for Machado-Joseph disease and constitute a proof of principle of the beneficial effects of early allele-specific silencing for therapy of this disease.
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Mutations in RPE65 protein is characterized by the loss of photoreceptors, although the molecular pathways triggering retinal cell death remain largely unresolved. The role of the Bcl-2 family of proteins in retinal degeneration is still controversial. However, alteration in Bcl-2-related proteins has been observed in several models of retinal injury. In particular, Bax has been suggested to play a crucial role in apoptotic pathways in murine glaucoma model as well as in retinal detachment-associated cell death. We demonstrated that Bcl-2-related signaling pathway is involved in Rpe65-dependent apoptosis of photoreceptors during development of the disease. Pro-apoptotic Bax alpha and beta isoforms were upregulated in diseased retina. This was associated with a progressive reduction of anti-apoptotic Bcl-2, reflecting imbalanced Bcl-2/Bax ratio as the disease progresses. Moreover, specific translocation of Bax beta from cytosol to mitochondria was observed in Rpe65-deficient retina. This correlated with the initiation of photoreceptor cell loss at 4 months of age, and further increased during disease development. Altogether, these data suggest that Bcl-2-apoptotic pathway plays a crucial role in Leber's congenital amaurosis disease. They further highlight a new regulatory mechanism of Bax-dependent apoptosis based on regulated expression and activation of specific isoforms of this protein.
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Motivation: Hormone pathway interactions are crucial in shaping plant development, such as synergism between the auxin and brassinosteroid pathways in cell elongation. Both hormone pathways have been characterized in detail, revealing several feedback loops. The complexity of this network, combined with a shortage of kinetic data, renders its quantitative analysis virtually impossible at present.Results: As a first step towards overcoming these obstacles, we analyzed the network using a Boolean logic approach to build models of auxin and brassinosteroid signaling, and their interaction. To compare these discrete dynamic models across conditions, we transformed them into qualitative continuous systems, which predict network component states more accurately and can accommodate kinetic data as they become available. To this end, we developed an extension for the SQUAD software, allowing semi-quantitative analysis of network states. Contrasting the developmental output depending on cell type-specific modulators enabled us to identify a most parsimonious model, which explains initially paradoxical mutant phenotypes and revealed a novel physiological feature.
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BACKGROUND: Regulatory T cells (Tregs) are key players in controlling the development of airway inflammation. However, their role in the mechanisms leading to tolerance in established allergic asthma is unclear. OBJECTIVE: To examine the role of Tregs in tolerance induction in a murine model of asthma. METHODS: Ovalbumin (OVA) sensitized asthmatic mice were depleted or not of CD25(+) T cells by anti-CD25 PC61 monoclonal antibody (mAb) before intranasal treatment (INT) with OVA, then challenged with OVA aerosol. To further evaluate the respective regulatory activity of CD4(+)CD25(+) and CD4(+)CD25(-) T cells, both T cell subsets were transferred from tolerized or non-tolerized animals to asthmatic recipients. Bronchoalveolar lavage fluid (BALF), T cell proliferation and cytokine secretion were examined. RESULTS: Intranasal treatment with OVA led to increased levels of IL-10, TGF-beta and IL-17 in lung homogenates, inhibition of eosinophil recruitment into the BALF and antigen specific T cell hyporesponsiveness. CD4(+)CD25(+)Foxp3(+) T cells were markedly upregulated in lungs and suppressed in vitro and in vivo OVA-specific T cell responses. Depletion of CD25(+) cells before OVA INT severely hampered tolerance induction as indicated by a strong recruitment of eosinophils into BALF and a vigorous T cell response to OVA upon challenge. However, the transfer of CD4(+)CD25(-) T cells not only suppressed antigen specific T cell responsiveness but also significantly reduced eosinophil recruitment as opposed to CD4(+)CD25(+) T cells. As compared with control mice, a significantly higher proportion of CD4(+)CD25(-) T cells from OVA treated mice expressed mTGF-beta. CONCLUSION: Both CD4(+)CD25(+) and CD4(+)CD25(-) T cells appear to be essential to tolerance induction. The relationship between both subsets and the mechanisms of their regulatory activity will have to be further analyzed.
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The failure of current strategies to provide an explanation for controversial findings on the pattern of pathophysiological changes in Alzheimer's Disease (AD) motivates the necessity to develop new integrative approaches based on multi-modal neuroimaging data that captures various aspects of disease pathology. Previous studies using [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) and structural magnetic resonance imaging (sMRI) report controversial results about time-line, spatial extent and magnitude of glucose hypometabolism and atrophy in AD that depend on clinical and demographic characteristics of the studied populations. Here, we provide and validate at a group level a generative anatomical model of glucose hypo-metabolism and atrophy progression in AD based on FDG-PET and sMRI data of 80 patients and 79 healthy controls to describe expected age and symptom severity related changes in AD relative to a baseline provided by healthy aging. We demonstrate a high level of anatomical accuracy for both modalities yielding strongly age- and symptom-severity- dependant glucose hypometabolism in temporal, parietal and precuneal regions and a more extensive network of atrophy in hippocampal, temporal, parietal, occipital and posterior caudate regions. The model suggests greater and more consistent changes in FDG-PET compared to sMRI at earlier and the inversion of this pattern at more advanced AD stages. Our model describes, integrates and predicts characteristic patterns of AD related pathology, uncontaminated by normal age effects, derived from multi-modal data. It further provides an integrative explanation for findings suggesting a dissociation between early- and late-onset AD. The generative model offers a basis for further development of individualized biomarkers allowing accurate early diagnosis and treatment evaluation.
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Despite the important benefits for firms of commercial initiatives on the Internet, e-commerce is still an emerging distribution channel, even in developed countries. Thus, more needs to be known about the mechanisms affecting its development. A large number of works have studied firms¿ e-commerce adoption from technological, intraorganizational, institutional, or other specific perspectives, but there is a need for adequately tested integrative frameworks. Hence, this work proposes and tests a model of firms¿ business-to-consumer (called B2C) e-commerce adoption that is founded on a holistic vision of the phenomenon. With this integrative approach, the authors analyze the joint influence of environmental, technological, and organizational factors; moreover, they evaluate this effect over time. Using various representative Spanish data sets covering the period 1996-2005, the findings demonstrate the suitability of the holistic framework. Likewise, some lessons are learned from the analysis of the key building blocks. In particular, the current study provides evidence for the debate about the effect of competitive pressure, since the findings show that competitive pressure disincentivizes e-commerce adoption in the long term. The results also show that the development or enrichment of the consumers¿ consumption patterns, the technological readiness of the market forces, the firm¿s global scope, and its competences in innovation continuously favor e-commerce adoption.
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Les plantes sont essentielles pour les sociétés humaines. Notre alimentation quotidienne, les matériaux de constructions et les sources énergétiques dérivent de la biomasse végétale. En revanche, la compréhension des multiples aspects développementaux des plantes est encore peu exploitée et représente un sujet de recherche majeur pour la science. L'émergence des technologies à haut débit pour le séquençage de génome à grande échelle ou l'imagerie de haute résolution permet à présent de produire des quantités énormes d'information. L'analyse informatique est une façon d'intégrer ces données et de réduire la complexité apparente vers une échelle d'abstraction appropriée, dont la finalité est de fournir des perspectives de recherches ciblées. Ceci représente la raison première de cette thèse. En d'autres termes, nous appliquons des méthodes descriptives et prédictives combinées à des simulations numériques afin d'apporter des solutions originales à des problèmes relatifs à la morphogénèse à l'échelle de la cellule et de l'organe. Nous nous sommes fixés parmi les objectifs principaux de cette thèse d'élucider de quelle manière l'interaction croisée des phytohormones auxine et brassinosteroïdes (BRs) détermine la croissance de la cellule dans la racine du méristème apical d'Arabidopsis thaliana, l'organisme modèle de référence pour les études moléculaires en plantes. Pour reconstruire le réseau de signalement cellulaire, nous avons extrait de la littérature les informations pertinentes concernant les relations entre les protéines impliquées dans la transduction des signaux hormonaux. Le réseau a ensuite été modélisé en utilisant un formalisme logique et qualitatif pour pallier l'absence de données quantitatives. Tout d'abord, Les résultats ont permis de confirmer que l'auxine et les BRs agissent en synergie pour contrôler la croissance de la cellule, puis, d'expliquer des observations phénotypiques paradoxales et au final, de mettre à jour une interaction clef entre deux protéines dans la maintenance du méristème de la racine. Une étude ultérieure chez la plante modèle Brachypodium dystachion (Brachypo- dium) a révélé l'ajustement du réseau d'interaction croisée entre auxine et éthylène par rapport à Arabidopsis. Chez ce dernier, interférer avec la biosynthèse de l'auxine mène à la formation d'une racine courte. Néanmoins, nous avons isolé chez Brachypodium un mutant hypomorphique dans la biosynthèse de l'auxine qui affiche une racine plus longue. Nous avons alors conduit une analyse morphométrique qui a confirmé que des cellules plus anisotropique (plus fines et longues) sont à l'origine de ce phénotype racinaire. Des analyses plus approfondies ont démontré que la différence phénotypique entre Brachypodium et Arabidopsis s'explique par une inversion de la fonction régulatrice dans la relation entre le réseau de signalisation par l'éthylène et la biosynthèse de l'auxine. L'analyse morphométrique utilisée dans l'étude précédente exploite le pipeline de traitement d'image de notre méthode d'histologie quantitative. Pendant la croissance secondaire, la symétrie bilatérale de l'hypocotyle est remplacée par une symétrie radiale et une organisation concentrique des tissus constitutifs. Ces tissus sont initialement composés d'une douzaine de cellules mais peuvent aisément atteindre des dizaines de milliers dans les derniers stades du développement. Cette échelle dépasse largement le seuil d'investigation par les moyens dits 'traditionnels' comme l'imagerie directe de tissus en profondeur. L'étude de ce système pendant cette phase de développement ne peut se faire qu'en réalisant des coupes fines de l'organe, ce qui empêche une compréhension des phénomènes cellulaires dynamiques sous-jacents. Nous y avons remédié en proposant une stratégie originale nommée, histologie quantitative. De fait, nous avons extrait l'information contenue dans des images de très haute résolution de sections transverses d'hypocotyles en utilisant un pipeline d'analyse et de segmentation d'image à grande échelle. Nous l'avons ensuite combiné avec un algorithme de reconnaissance automatique des cellules. Cet outil nous a permis de réaliser une description quantitative de la progression de la croissance secondaire révélant des schémas développementales non-apparents avec une inspection visuelle classique. La formation de pôle de phloèmes en structure répétée et espacée entre eux d'une longueur constante illustre les bénéfices de notre approche. Par ailleurs, l'exploitation approfondie de ces résultats a montré un changement de croissance anisotropique des cellules du cambium et du phloème qui semble en phase avec l'expansion du xylème. Combinant des outils génétiques et de la modélisation biomécanique, nous avons démontré que seule la croissance plus rapide des tissus internes peut produire une réorientation de l'axe de croissance anisotropique des tissus périphériques. Cette prédiction a été confirmée par le calcul du ratio des taux de croissance du xylème et du phloème au cours de développement secondaire ; des ratios élevés sont effectivement observés et concomitant à l'établissement progressif et tangentiel du cambium. Ces résultats suggèrent un mécanisme d'auto-organisation établi par un gradient de division méristématique qui génèrent une distribution de contraintes mécaniques. Ceci réoriente la croissance anisotropique des tissus périphériques pour supporter la croissance secondaire. - Plants are essential for human society, because our daily food, construction materials and sustainable energy are derived from plant biomass. Yet, despite this importance, the multiple developmental aspects of plants are still poorly understood and represent a major challenge for science. With the emergence of high throughput devices for genome sequencing and high-resolution imaging, data has never been so easy to collect, generating huge amounts of information. Computational analysis is one way to integrate those data and to decrease the apparent complexity towards an appropriate scale of abstraction with the aim to eventually provide new answers and direct further research perspectives. This is the motivation behind this thesis work, i.e. the application of descriptive and predictive analytics combined with computational modeling to answer problems that revolve around morphogenesis at the subcellular and organ scale. One of the goals of this thesis is to elucidate how the auxin-brassinosteroid phytohormone interaction determines the cell growth in the root apical meristem of Arabidopsis thaliana (Arabidopsis), the plant model of reference for molecular studies. The pertinent information about signaling protein relationships was obtained through the literature to reconstruct the entire hormonal crosstalk. Due to a lack of quantitative information, we employed a qualitative modeling formalism. This work permitted to confirm the synergistic effect of the hormonal crosstalk on cell elongation, to explain some of our paradoxical mutant phenotypes and to predict a novel interaction between the BREVIS RADIX (BRX) protein and the transcription factor MONOPTEROS (MP),which turned out to be critical for the maintenance of the root meristem. On the same subcellular scale, another study in the monocot model Brachypodium dystachion (Brachypodium) revealed an alternative wiring of auxin-ethylene crosstalk as compared to Arabidopsis. In the latter, increasing interference with auxin biosynthesis results in progressively shorter roots. By contrast, a hypomorphic Brachypodium mutant isolated in this study in an enzyme of the auxin biosynthesis pathway displayed a dramatically longer seminal root. Our morphometric analysis confirmed that more anisotropic cells (thinner and longer) are principally responsible for the mutant root phenotype. Further characterization pointed towards an inverted regulatory logic in the relation between ethylene signaling and auxin biosynthesis in Brachypodium as compared to Arabidopsis, which explains the phenotypic discrepancy. Finally, the morphometric analysis of hypocotyl secondary growth that we applied in this study was performed with the image-processing pipeline of our quantitative histology method. During its secondary growth, the hypocotyl reorganizes its primary bilateral symmetry to a radial symmetry of highly specialized tissues comprising several thousand cells, starting with a few dozens. However, such a scale only permits observations in thin cross-sections, severely hampering a comprehensive analysis of the morphodynamics involved. Our quantitative histology strategy overcomes this limitation. We acquired hypocotyl cross-sections from tiled high-resolution images and extracted their information content using custom high-throughput image processing and segmentation. Coupled with an automated cell type recognition algorithm, it allows precise quantitative characterization of vascular development and reveals developmental patterns that were not evident from visual inspection, for example the steady interspace distance of the phloem poles. Further analyses indicated a change in growth anisotropy of cambial and phloem cells, which appeared in phase with the expansion of xylem. Combining genetic tools and computational modeling, we showed that the reorientation of growth anisotropy axis of peripheral tissue layers only occurs when the growth rate of central tissue is higher than the peripheral one. This was confirmed by the calculation of the ratio of the growth rate xylem to phloem throughout secondary growth. High ratios are indeed observed and concomitant with the homogenization of cambium anisotropy. These results suggest a self-organization mechanism, promoted by a gradient of division in the cambium that generates a pattern of mechanical constraints. This, in turn, reorients the growth anisotropy of peripheral tissues to sustain the secondary growth.
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Diplomityön tarkoituksena on kehittää kolmiulotteinen malli kerrosleijupoltolle. Työn kirjallisuusosa sisältää seuraavat perusteet kerrosleijupolton tekniikasta: yleistiedot, leijutus- ja palamisilmiöt, kiinteän aineen ja kaasun sekoittuminen, päästöt ja lämmönsiirto. Lisäksi palamissysteemin mallinnuksen perusteet ja ratkaisumenetelmät ovat esitelty. Työn mallinnusosassa kehitetty koodi on ohjelmoitu Fortran-ohjelmointikielellä. Kehitetty malli perustuu olemassa olevaan malliin kiertoleijupoltosta. Yhtälö kiintoainekonsentraatioprofiilille on vaihdettu ja kiertovirta on poistettu koodista. Mallilla on tehty herkkyystarkasteluja polttoaineen ja kaasun sekoittumisen sekä reaktiokertoimen vaikutukselle. Visualisointi on tehty ohjelmassa Tecplot 360 ja mallinnustuloksia on vertailtu mitattuihin tuloksiin. Mallin laskemattulokset vastaavat hyvin mittaustuloksia ja kokemusperäisiä tietoja; monissa tapauksissa malli pystyy kvantitatiivisesti kuvaamaan parametrien variointia ja kaikissa tapauksissa malli antaa ainakin kvalitatiivisesti oikeita tuloksia. Työhön liittyvän kehityksen ja mallinnuskokemuksen perusteella on tehty ehdotukset mallin tulevaa kehitystä ja mittauksia varten.
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Mutations in GDAP1, which encodes protein located in the mitochondrial outer membrane, cause axonal recessive (AR-CMT2), axonal dominant (CMT2K) and demyelinating recessive (CMT4A) forms of Charcot-Marie-Tooth (CMT) neuropathy. Loss of function recessive mutations in GDAP1 are associated with decreased mitochondrial fission activity, while dominant mutations result in impairment of mitochondrial fusion with increased production of reactive oxygen species and susceptibility to apoptotic stimuli. GDAP1 silencing in vitro reduces Ca2+ inflow through store-operated Ca2+ entry (SOCE) upon mobilization of endoplasmic reticulum (ER) Ca2+, likely in association with an abnormal distribution of the mitochondrial network. To investigate the functional consequences of lack of GDAP1 in vivo, we generated a Gdap1 knockout mouse. The affected animals presented abnormal motor behavior starting at the age of 3 months. Electrophysiological and biochemical studies confirmed the axonal nature of the neuropathy whereas histopathological studies over time showed progressive loss of motor neurons (MNs) in the anterior horn of the spinal cord and defects in neuromuscular junctions. Analyses of cultured embryonic MNs and adult dorsal root ganglia neurons from affected animals demonstrated large and defective mitochondria, changes in the ER cisternae, reduced acetylation of cytoskeletal α-tubulin and increased autophagy vesicles. Importantly, MNs showed reduced cytosolic calcium and SOCE response. The development and characterization of the GDAP1 neuropathy mice model thus revealed that some of the pathophysiological changes present in axonal recessive form of the GDAP1-related CMT might be the consequence of changes in the mitochondrial network biology and mitochondria-endoplasmic reticulum interaction leading to abnormalities in calcium homeostasis.
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Ohjelmistojen tärkeys nykypäivän yhteiskunnalle kasvaa jatkuvasti. Monia ohjelmistoprojekteja vaivaavat ongelmat aikataulussa pysymisestä, korkean tuottavuuden ylläpitämisestä ja riittävän korkeasta laadusta. Ohjelmistokehitysprosessien parantamisessa on naiden ongelmien minimoimiseksi tehty suuria investointeja. Investointien syynä on ollut olettamus ohjelmistokehityksen kapasiteetin suora riippuvuus tuotteen laadusta. Tämän tutkimuksen tarkoituksena oli tutkia Ohjelmistokehitysprosessien parantamisen mahdollisuuksia. Olemassaolevat ohjelmistokehityksen ja Ohjelmistokehitysprosessin parantamisen mallit, tekniikat ja metodologiat esiteltiin. Esiteltyjen mallien, tekniikoiden ja metodologioiden soveltuvuus analysoitiin ja suositus mallien käytöstä annettiin.
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Elevated serum phosphorus, calcium, and fibroblast growth factor 23 (FGF23) levels are associated with cardiovascular disease in chronic renal disease. This study evaluated the effects of sucroferric oxyhydroxide (PA21), a new iron-based phosphate binder, versus lanthanum carbonate (La) and sevelamer carbonate (Se), on serum FGF23, phosphorus, calcium, and intact parathyroid hormone (iPTH) concentrations, and the development of vascular calcification in adenine-induced chronic renal failure (CRF) rats. After induction of CRF, renal function was significantly impaired in all groups: uremic rats developed severe hyperphosphatemia, and serum iPTH increased significantly. All uremic rats (except controls) then received phosphate binders for 4 weeks. Hyperphosphatemia and increased serum iPTH were controlled to a similar extent in all phosphate binder-treatment groups. Only sucroferric oxyhydroxide was associated with significantly decreased FGF23. Vascular calcifications of the thoracic aorta were decreased by all three phosphate binders. Calcifications were better prevented at the superior part of the thoracic and abdominal aorta in the PA21 treated rats. In adenine-induced CRF rats, sucroferric oxyhydroxide was as effective as La and Se in controlling hyperphosphatemia, secondary hyperparathyroidism, and vascular calcifications. The role of FGF23 in calcification remains to be confirmed.
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This thesis studies evaluation of software development practices through an error analysis. The work presents software development process, software testing, software errors, error classification and software process improvement methods. The practical part of the work presents results from the error analysis of one software process. It also gives improvement ideas for the project. It was noticed that the classification of the error data was inadequate in the project. Because of this it was impossible to use the error data effectively. With the error analysis we were able to show that there were deficiencies in design and analyzing phases, implementation phase and in testing phase. The work gives ideas for improving error classification and for software development practices.