45 resultados para Linear forms in logarithms
em Universit
Resumo:
BACKGROUND: The long latent stage seen in syphilis, followed by chronic central nervous system infection and inflammation, can be explained by the persistence of atypical cystic and granular forms of Treponema pallidum. We investigated whether a similar situation may occur in Lyme neuroborreliosis. METHOD: Atypical forms of Borrelia burgdorferi spirochetes were induced exposing cultures of Borrelia burgdorferi (strains B31 and ADB1) to such unfavorable conditions as osmotic and heat shock, and exposure to the binding agents Thioflavin S and Congo red. We also analyzed whether these forms may be induced in vitro, following infection of primary chicken and rat neurons, as well as rat and human astrocytes. We further analyzed whether atypical forms similar to those induced in vitro may also occur in vivo, in brains of three patients with Lyme neuroborreliosis. We used immunohistochemical methods to detect evidence of neuroinflammation in the form of reactive microglia and astrocytes. RESULTS: Under these conditions we observed atypical cystic, rolled and granular forms of these spirochetes. We characterized these abnormal forms by histochemical, immunohistochemical, dark field and atomic force microscopy (AFM) methods. The atypical and cystic forms found in the brains of three patients with neuropathologically confirmed Lyme neuroborreliosis were identical to those induced in vitro. We also observed nuclear fragmentation of the infected astrocytes using the TUNEL method. Abundant HLA-DR positive microglia and GFAP positive reactive astrocytes were present in the cerebral cortex. CONCLUSION: The results indicate that atypical extra- and intracellular pleomorphic and cystic forms of Borrelia burgdorferi and local neuroinflammation occur in the brain in chronic Lyme neuroborreliosis. The persistence of these more resistant spirochete forms, and their intracellular location in neurons and glial cells, may explain the long latent stage and persistence of Borrelia infection. The results also suggest that Borrelia burgdorferi may induce cellular dysfunction and apoptosis. The detection and recognition of atypical, cystic and granular forms in infected tissues is essential for the diagnosis and the treatment as they can occur in the absence of the typical spiral Borrelia form.
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To evaluate antibody specificities induced by simian immunodeficiency virus (SIV) versus human immunodeficiency virus type 1 (HIV-1) envelope antigens in nonhuman primate (NHP), we profiled binding antibody responses to linear epitopes in NHP studies with HIV-1 or SIV immunogens. We found that, overall, HIV-1 Env IgG responses were dominated by V3, with the notable exception of the responses to the vaccine strain A244 Env that were dominated by V2, whereas the anti-SIVmac239 Env responses were dominated by V2 regardless of the vaccine regimen.
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OBJECTIVE: While there is a dose-response relationship between physical activity (PA) and health benefit, little is known about the effectiveness of different PA prescriptions on total daily PA. AIM: To test, under real-life conditions and using an objective, non-invasive measurement technique (accelerometry), the effect of prescribing additional physical activity (walking only) of different durations (30, 60 and 90 min/day) on compliance (to the activity prescribed) and compensation (to total daily PA). Participants in each group were prescribed 5 sessions of walking per week over 4 weeks. METHODS: 55 normal-weight and overweight women (mean BMI 25 ± 5 kg/m(2), height 165 ± 1 cm, weight 68 ± 2 kg and mean age 27 ± 1 years) were randomly assigned to 3 prescription groups: 30, 60 or 90 min/day PA. RESULTS: Walking duration resulted in an almost linear increase in the number of steps per day during the prescription period from an average of about 10,000 steps per day for the 30-min prescription to about 14,000 for the 90-min prescription. Compliance was excellent for the 30-min prescription but decreased significantly with 60-min and 90-min prescriptions. In parallel, degree of compensation subsequent to exercise increased progressively as length of prescription increased. CONCLUSION: A 30-min prescription of extra walking 5 times per week was well tolerated. However, in order to increase total PA further, much more than 60 min of walking may need to be prescribed in the majority of individuals. While total exercise 'volume' increased with prescriptions longer than 30 min, compliance to the prescription decreased and greater compensation was evident. © 2014 S. Karger GmbH, Freiburg.
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Juvenile spondylarthropathies (JSpAs) comprise a group of rheumatic diseases distinct from other categories of juvenile arthritis. Several classification systems have been applied, and some are specific for children, such as the seronegative enthesopathy and arthropathy (SEA) syndrome and the enthesitis-related arthritis, diagnostic forms in the International League of Associations for Rheumatism (ILAR) classification. JSpA seems more frequent than was previously believed, but actual epidemiological data show important variations between studies. Compared to adult patients, children with JSpA present with peripheral arthritis and enthesitis early in disease but sacroiliac and spine joints involvement many years later. A multidisciplinary team in a paediatric environment should be responsible for the management of children with spondylarthropathies to ensure the best care for these children with their chronic disease and risk of long-term disability. Recent advances in the treatment of rheumatic diseases with biological agents show promising results in children with JSpA. Further research needs to be conducted to increase our knowledge of the long-term outcome of these patients, to improve management, and to prevent long-term consequences of the disease.
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Humans and mice lacking functional caspase-8 in T cells manifest a profound immunodeficiency syndrome due to defective T cell antigen receptor (TCR)-induced NF-kappaB signaling and proliferation. It is unknown how caspase-8 is activated following T cell stimulation, and what is the caspase-8 substrate(s) that is necessary to initiate T cell cycling. We observe that following TCR ligation, a small portion of total cellular caspase-8 and c-FLIP(L) rapidly migrate to lipid rafts where they associate in an active caspase complex. Activation of caspase-8 in lipid rafts is followed by rapid cleavage of c-FLIP(L) at a known caspase-8 cleavage site. The active caspase.c-FLIP complex forms in the absence of Fas (CD95/APO1) and associates with the NF-kappaB signaling molecules RIP1, TRAF2, and TRAF6, as well as upstream NF-kappaB regulators PKC theta, CARMA1, Bcl-10, and MALT1, which connect to the TCR. The lack of caspase-8 results in the absence of MALT1 and Bcl-10 in the active caspase complex. Consistent with this observation, inhibition of caspase activity attenuates NF-kappaB activation. The current findings define a link among TCR, caspases, and the NF-kappaB pathway that occurs in a sequestered lipid raft environment in T cells.
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A child's natural gait pattern may be affected by the gait laboratory environment. Wearable devices using body-worn sensors have been developed for gait analysis. The purpose of this study was to validate and explore the use of foot-worn inertial sensors for the measurement of selected spatio-temporal parameters, based on the 3D foot trajectory, in independently walking children with cerebral palsy (CP). We performed a case control study with 14 children with CP aged 6-15 years old and 15 age-matched controls. Accuracy and precision of the foot-worn device were measured using an optical motion capture system as the reference system. Mean accuracy±precision for both groups was 3.4±4.6cm for stride length, 4.3±4.2cm/s for speed and 0.5±2.9° for strike angle. Longer stance and shorter swing phases with an increase in double support were observed in children with CP (p=0.001). Stride length, speed and peak angular velocity during swing were decreased in paretic limbs, with significant differences in strike and lift-off angles. Children with cerebral palsy showed significantly higher inter-stride variability (measured by their coefficient of variation) for speed, stride length, swing and stance. During turning trajectories speed and stride length decreased significantly (p<0.01) for both groups, whereas stance increased significantly (p<0.01) in CP children only. Foot-worn inertial sensors allowed us to analyze gait spatiotemporal data outside a laboratory environment with good accuracy and precision and congruent results with what is known of gait variations during linear walking in children with CP.
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L'ARN Polymérase III (Pol III) transcrit un ensemble de petits ARN non traduits impliqués dans des processus cellulaires tels que la biosynthèse des protéines, la maturation des ARNs ou le contrôle transcriptionnel. De ce fait, la Pol III joue un rôle important dans la régulation de la croissance et la prolifération cellulaire. L'initiation de la transcription par la Pol III nécessite l'interaction entre des facteurs de transcription et le complexe de la Pol III lui-même. Un sous- complexe de la Pol III, composé de 3 sous-unités, HsRPC3, HsRPC6 et HsRPC7 sert d'intermédiaire dans cette interaction. Dans cette étude, nous avons caractérisé une nouvelle sous-unité de la Pol III, HsRPC7-Like, homologue à HsRPC7. Nous avons montré que ces deux homologues se trouvent spécifiquement chez les vertébrés. Ils proviennent d'un ancêtre commun qui, après duplication il y a 600 millions d'années, a donné naissance à ces deux paralogues. Dans les cellules humaines, deux formes de Pol III coexistent : l'une contientt HsRPC7, l'autre HsRPC7-Like. Nous avons localisé, à l'échelle du génome entier, la présence de ces deux formes de Pol III dans des cellules humaines et dans le foie de souris. Les deux sous-unités ont démontré des caractéristiques identiques, suggérant qu'elles possèdent des fonctions similaires. Cependant, nous avons analysé les motifs d'expression des gènes codant pour RPC7 et RPC7-Like dans des lignées cellulaires dans des conditions variées telles que la concentration de sérum et la densité cellulaire, ainsi que les motifs d'expression dans le foie de souris et des cellules d'hépatocarcinome de souris. Nos résultats suggèrent que l'expression de ces deux sous-untiés varie en fonction de l'activité de prolifération de la cellule. - RNA polymerase III (Pol III) transcribes a set of genes coding for short untranslated RNAs involved in essential cellular processes as for example protein biosynthesis, RNA maturation, and transcriptional control. Thereby Pol III plays an important role in regulating cell growth and proliferation. Initiation of Pol III transcription requires interactions between transcription factors and the Pol III core complex. A Pol III sub-complex composed of three subunits, HsRPC3, HsRPC6, and HsRPC7 mediates this interaction. In this study, we have characterized a new Pol III subunit, HsRPC7-Like, an homologue of HsRPC7. We have shown that these two homologues are specific to vertebrates and originate from an ancestor gene that duplicated 600 mio years ago to give birth to two paralogues. In human cells, two forms of Pol III coexist, one containing HsRPC7 and the other HsRPC7-Like. We have localized, genome-wide, these two Pol III forms in human cells and mouse liver. Both subunits were found on all types of Pol III genes, suggesting that they share similar function. However, we analysed the expression patterns of the RPC7 and RPC7-Like coding genes under various conditions of serum concentration and cell density in different cell lines, as well as expression patterns in mouse liver and mouse hepatocarcinoma cells. Our results suggest that the expression of these two subunits varies with the proliferation rate of the cell.
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Spirituality addresses the need to give meaning to life events and is characterized by the relationship with oneself, others and the universe. This article aims to provide an overview of the empirical knowledge, and the prevailing thoughts about spirituality in nursing and suggest perspectives for future directions. The literature review was conducted using the main databases; 36 articles, published between 2008-2013, were selected. The themes covered include the definitions of the spirituality, the spiritual care and the spiritual well-being. Spirituality differs from, yet is not opposed to religion and takes different forms in multicultural and secular societies. Cancer incites existential questions and impacts quality of life, and spiritual well-being is recognized as a good indicator of quality of life for people living with cancer. Professional caregivers are concerned about the needs and spiritual well-being of their patients and often consider interventions to address them. This article reflects the depth of thought and research in nursing and touches on both discipline-specific and interdisciplinary issues.
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The photoreceptor phytochrome B (phyB) interconverts between the biologically active Pfr (λmax = 730 nm) and inactive Pr (λmax = 660 nm) forms in a red/far-red-dependent fashion and regulates, as molecular switch, many aspects of light-dependent development in Arabidopsis thaliana. phyB signaling is launched by the biologically active Pfr conformer and mediated by specific protein-protein interactions between phyB Pfr and its downstream regulatory partners, whereas conversion of Pfr to Pr terminates signaling. Here, we provide evidence that phyB is phosphorylated in planta at Ser-86 located in the N-terminal domain of the photoreceptor. Analysis of phyB-9 transgenic plants expressing phospho-mimic and nonphosphorylatable phyB-yellow fluorescent protein (YFP) fusions demonstrated that phosphorylation of Ser-86 negatively regulates all physiological responses tested. The Ser86Asp and Ser86Ala substitutions do not affect stability, photoconversion, and spectral properties of the photoreceptor, but light-independent relaxation of the phyB(Ser86Asp) Pfr into Pr, also termed dark reversion, is strongly enhanced both in vivo and in vitro. Faster dark reversion attenuates red light-induced nuclear import and interaction of phyB(Ser86Asp)-YFP Pfr with the negative regulator PHYTOCHROME INTERACTING FACTOR3 compared with phyB-green fluorescent protein. These data suggest that accelerated inactivation of the photoreceptor phyB via phosphorylation of Ser-86 represents a new paradigm for modulating phytochrome-controlled signaling.
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RESUME En Amérique Centrale et en Amérique du Sud, la leishmaniose cutanéo-muqueuse (LCM) est provoquée par le protozoaire Leishmania du sous-genre Viannia dont font partie L. (V.) braziliensis, L. (V.) panamensis et L. (V.) guyanensis. Dans la LCM, après guérison apparente de la lésion primitive, des lésions secondaires peuvent apparaître dues à la migration de l'infection à partir du site d'inoculation vers les muqueuses de l'ororhino-pharynx. Ce type de dissémination, communément appelé métastase, peut se produire plusieurs années après la guérison de la lésion cutanée initiale, et est un facteur majeur contribuant à la morbidité associée à la LCM. L'expression reproductible de l'activité métastatique au sein de populations discrètes de leishmanies chez le hamster fournit un modèle expérimental permettant d'étudier le degré de virulence du parasite. Nous avons utilisé des clones de L. (V.) guyanensis présentant des phénotypes stables allant d'un caractère hautement métastatique (M+) à non-métastatique (M-) comme outils pour mettre en évidence des facteurs spécifiques liés à la métastase chez les leishmanies du Nouveau Monde. Des analyses protéomiques comparatives utilisant l'électrophorèse bidimensionnelle sur gel de polyacrylamide couplée à de la spectrométrie de masse ont permis l'identification de plusieurs formes de la tryparedoxine peroxidase (TXNPx) en tant que polypeptides associés au phénotype métastatique. TXNPx, une enzyme de la famille des peroxiredoxines (Prxs), protéines antioxydantes, fonctionne comme la dernière peroxydase d'une cascade d'oxydoréductases qui réduit le peroxyde d'hydrogène aux dépens de NADPH. Toutes les Prxs sont caractérisées par un (1-Cys Prx) ou par deux résidus cystéines (2-Cys Prx), respectivement placés dans un environnement structurel conservé de la protéine et sont centrales dans la réaction catalytique. Des immuno-empreintes (« immunoblotting ») ont révélé que TXNPx est présente sous forme dimérique dans les promastigotes (M+) alors que dans les promastigotes, (M-) TXNPx est présente sous forme monomérique et dimérique. Cette caractéristique spécifique de dimérisation pourrait expliquer les différentes activités enzymatiques observées entre les deux promastigotes (M+) et (M-) en présence de peroxyde d'hydrogène ainsi que leur différence de survie et de charge parasitaire à l'intérieur des macrophages. Par conséquent, le processus métastatique pourrait être lié à la capacité du parasite à échapper efficacement aux défenses microbicides de la cellule hôte. ABSTRACT In South and Central America, protozoan parasites of the Leishmania Viannia subgenus including L. (V.) braziliensis, L. (V.) guyanensis and L. (V). panamensis cause mucocutaneous leishmaniasis (MCL). In MCL, after apparent cure of the primary lesion, secondary lesions may appear in the nasopharyngeal tissues of the infected host due to dissemination of the infection from the inoculation site. This type of dissemination, known as metastasis, can occur several years after healing of the original cutaneous lesion, and is a major contributory factor to the morbidity associated with MCL. The reproducible expression of metastasis by discrete populations of Leishmania parasites in hamsters provides an experimental model to examine the expression of parasite virulence. We used laboratory clones of L. (V.) guyanensis with stable phenotypes ranging from highly metastatic (M+) to non-metastatic (M-) as tools for the discovery of specific factors associated with metastasis in New World Leishmania species. Comparative proteome analyses via 2D-electrophoresis (2-DE) coupled with mass spectrometry (MS) enabled the identification of various isoforms of tryparedoxin peroxidase (TXNPx) as polypeptides associated with the metastatic phenotype. TXNPx, an enzyme related to the antioxidant peroxiredoxin family (Prx) functions as the terminal peroxidase of a redox cascade that reduces hydroperoxides by NADPH. All Prxs are characterized by one (1-Cys Prx) or two cysteine residue(s) (2-Cys Prx), respectively, located in a conserved structural environment of the protein which are central for the catalytic reaction. Immunoblotting analysis revealed that, under non-reducing denaturing conditions, TXNPx is present in dimeric forms in (M+) promastigotes, whereas in (M-) promastigotes, both monomeric and dimeric forms are found. This specific dimerization feature may explain the different enzymatic activities of both (M+) and (M-) promastigote parasites in the presence of H2O2 and their difference in survival and parasite load inside macrophages. Therefore, the metastatic process could be related to the ability of the parasite to efficiently evade the microbicidal effect of the host cell.
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Raman spectroscopy has become an attractive tool for the analysis of pharmaceutical solid dosage forms. In the present study it is used to ensure the identity of tablets. The two main applications of this method are release of final products in quality control and detection of counterfeits. Twenty-five product families of tablets have been included in the spectral library and a non-linear classification method, the Support Vector Machines (SVMs), has been employed. Two calibrations have been developed in cascade: the first one identifies the product family while the second one specifies the formulation. A product family comprises different formulations that have the same active pharmaceutical ingredient (API) but in a different amount. Once the tablets have been classified by the SVM model, API peaks detection and correlation are applied in order to have a specific method for the identification and allow in the future to discriminate counterfeits from genuine products. This calibration strategy enables the identification of 25 product families without error and in the absence of prior information about the sample. Raman spectroscopy coupled with chemometrics is therefore a fast and accurate tool for the identification of pharmaceutical tablets.
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We introduce disk matrices which encode the knotting of all subchains in circular knot configurations. The disk matrices allow us to dissect circular knots into their subknots, i.e. knot types formed by subchains of the global knot. The identification of subknots is based on the study of linear chains in which a knot type is associated to the chain by means of a spatially robust closure protocol. We characterize the sets of observed subknot types in global knots taking energy-minimized shapes such as KnotPlot configurations and ideal geometric configurations. We compare the sets of observed subknots to knot types obtained by changing crossings in the classical prime knot diagrams. Building upon this analysis, we study the sets of subknots in random configurations of corresponding knot types. In many of the knot types we analyzed, the sets of subknots from the ideal geometric configurations are found in each of the hundreds of random configurations of the same global knot type. We also compare the sets of subknots observed in open protein knots with the subknots observed in the ideal configurations of the corresponding knot type. This comparison enables us to explain the specific dispositions of subknots in the analyzed protein knots.
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Path integration is known to provide information to keep track of spatial location. Surprisingly, few investigations concerning sex differences in computation of the traveling distance have been done. This work was aimed at analyzing the reproduction of both passive and active linear displacements in women and men. To this end, the displacement of blindfolded subjects was done in a wheelchair, then on foot, three times in each condition for a fixed distance. Copies of passive and active traveling distance, distance estimations and pointing responses towards the starting point were analyzed. In passive condition and comparatively to men, women error was larger. Whereas traveling distance was generally underestimated in women, it was overestimated in men. In active condition, no sex differences were observed. When blindfolded subjects have to estimate the traveling distance, the female error was larger than the male one. But, when subjects were asked to indicate the visual cue corresponding to the traveling distance, the male error was larger than the female one. Finally, pointing to the starting point (0°) after a whole-body rotation showed a larger deviation from 0° in men than in women. These results suggest that sex of the subjects influence brain computation of path integration information.
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Apathy is a complex, behavioural disorder associated with reduced spontaneous initiation of actions. Although present in mild forms in some healthy people, it is a pathological state in conditions such as Alzheimer's and Parkinson's disease where it can have profoundly devastating effects. Understanding the mechanisms underlying apathy is therefore of urgent concern but this has proven difficult because widespread brain changes in neurodegenerative diseases make interpretation difficult and there is no good animal model. Here we present a very rare case with profound apathy following bilateral, focal lesions of the basal ganglia, with globus pallidus regions that connect with orbitofrontal (OFC) and ventromedial prefrontal cortex (VMPFC) particularly affected. Using two measures of oculomotor decision-making we show that apathy in this individual was associated with reward insensitivity. However, reward sensitivity could be established partially with levodopa and more effectively with a dopamine receptor agonist. Concomitantly, there was an improvement in the patient's clinical state, with reduced apathy, greater motivation and increased social interactions. These findings provide a model system to study a key neuropsychiatric disorder. They demonstrate that reward insensitivity associated with basal ganglia dysfunction might be an important component of apathy that can be reversed by dopaminergic modulation.
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MAP1a is a microtubule-associated protein with an apparent molecular weight of 360 kDa that is found in the axonal and dendritic processes of neurons. Two monoclonal anti-MAP1a antibodies anti-A and anti-BW6, revealed different epitope distributions in the adult mouse cerebellum. Anti-A stained Purkinje and granule cells uniformly throughout the cerebellum. In contrast, anti-BW6 selectively stained the dendriites of a subset of Purkinje cells, revealing parasagittal bands of immunoreactivity in the molecular layer. The compartmentation of the BW6 epitope was compared to the Purkine cells as revealed by immunostaining with anti-zebrin II, a well known antigen expressed selectively by bands of Purkinje cells. The anti-BW6 staining pattern was complementary to the zebrin II bands, the zebrin II- Purkinjke cells having BW6+ dendrites. These results demonstrate that MAP1a is present in two forms in the mouse cerebellum, one of which is segregated into parasagittal bands. This may indicate a unique MAP1a isoform or may reflect differences in the metabolic states of Purkinje cell classes, and regional differences in their functions.