941 resultados para Nonlinear functional analysis


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The sciarid DNA puff C4 BhC4-1 gene is amplified and transcribed in salivary glands at the end of the larval stage. In transgenic Drosophila, the BhC4-1 promoter drives transcription in prepupal salivary glands and in the ring gland of late embryos. A bioinformatics analysis has identified 162 sequences similar to distinct regions of the BhC4-1 proximal promoter, which are predominantly located either in 5` or 3` regions or introns in the Drosophila melanogaster genome. A significant number of the identified sequences are found in the regulatory regions of Drosophila genes that are expressed in the salivary gland. Functional assays in Drosophila reveal that the BhC4-1 proximal promoter contains both a 129 bp (-186/-58) salivary gland enhancer and a 67 bp (-253/-187) ring gland enhancer that drive tissue specific patterns of developmentally regulated gene expression, irrespective of their orientation.

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Background and Purpose-Functional MRI is a powerful tool to investigate recovery of brain function in patients with stroke. An inherent assumption in functional MRI data analysis is that the blood oxygenation level-dependent (BOLD) signal is stable over the course of the examination. In this study, we evaluated the validity of such assumption in patients with chronic stroke. Methods-Fifteen patients performed a simple motor task with repeated epochs using the paretic and the unaffected hand in separate runs. The corresponding BOLD signal time courses were extracted from the primary and supplementary motor areas of both hemispheres. Statistical maps were obtained by the conventional General Linear Model and by a parametric General Linear Model. Results-Stable BOLD amplitude was observed when the task was executed with the unaffected hand. Conversely, the BOLD signal amplitude in both primary and supplementary motor areas was progressively attenuated in every patient when the task was executed with the paretic hand. The conventional General Linear Model analysis failed to detect brain activation during movement of the paretic hand. However, the proposed parametric General Linear Model corrected the misdetection problem and showed robust activation in both primary and supplementary motor areas. Conclusions-The use of data analysis tools that are built on the premise of a stable BOLD signal may lead to misdetection of functional regions and underestimation of brain activity in patients with stroke. The present data urge the use of caution when relying on the BOLD response as a marker of brain reorganization in patients with stroke. (Stroke. 2010; 41:1921-1926.)

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Studies have provided evidence of the important effects of omega-3 fatty acid on the brain in neurological conditions, including epilepsy. Previous data have indicated that omega-3 fatty acids lead to prevention of status epilepticus-associated neuropathological changes in the hippocampal formation of rats with epilepsy. Omega-3 fatty acid supplementation has resulted in extensive preservation of GABAergic cells in animals with epilepsy. This study investigated the interplay of these effects with neurogenesis and brain-derived neurotrophic factor (BDNF). The results clearly showed a positive effect of long-term omega-3 fatty acid supplementation on brain plasticity in animals with epilepsy. Enhanced hippocampal neurogenesis and BDNF levels and preservation of interneurons expressing parvalbumin were observed. Parvalbumin-positive cells were identified as surviving instead of newly formed cells. Additional investigations are needed to determine the electrophysiological properties of the newly formed cells and to clarify whether the effects of omega-3 fatty acids on brain plasticity are accompanied by functional gain in animals with epilepsy. (C) 2009 Elsevier Inc. All rights reserved.

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The Schistosoma mansoni fatty acid binding protein (FABP), SmA, is a vaccine candidate against, S. mansoni and F hepatica. Previously, we demonstrated the importance of a correct fold to achieve protection in immunized animals after cercariae challenge [[10]. C.R.R. Ramos, R.C.R. Figueredo, T.A. Pertinhez, M.M. Vilar, A.L.T.O. Nascimento, M. Tendler, I. Raw, A. Spisni, P.L. Ho, Gene structure and M20T polymorphism of the Schistosoma mansoni Sm14 fatty acid-binding protein: structural, functional and immunoprotection analysis. J. Biol. Chem. 278 (2003) 12745-12751]. Here we show that the reduction of vaccine efficacy over time is due to protein dimerization and subsequent aggregation. We produced the mutants Sm14-M20(C62S) and Sm14M20(C62V) that, as expected, did not dimerize in SDS-PAGE. Molecular dynamics calculations and unfolding experiments highlighted a higher structural stability of these mutants with respect to the wild-type. In addition, we found that the mutated proteins, after thermal denaturation, refolded to their active native molecular architecture as proved by the recovery of the fatty acid binding ability. Sm14-M20(C62V) turned out to be the more stable form over time, providing the basis to determine the first 3D solution structure of a Sm14 protein in its apo-form. Overall, Sm14-M20(C62V) possesses an improved structural stability over time, an essential feature to preserve its immunization capability and, in experimentally immunized animals, it exhibits a protection effect against S. mansoni cercariae infections comparable to the one obtained with the wild-type protein. These facts indicate this protein as a good lead molecule for large-scale production and for developing an effective Sm14 based anti-helminthes vaccine. (C) 2008 Elsevier B.V. All rights reserved.

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There are many techniques for the treatment of hip dysplasia, and novel research is currently being undertaken in the hope of obtaining more efficient and less traumatic techniques. The denervation of the hip joint capsule is a simple and effective technique that allows recovery of the functional activity of the affected limbs in significantly less time than other techniques. This surgical procedure consists of removing the acetabular periosteum, thus eliminating the nerve fibres with consequent analgesia. The aim of this investigation was to quantify the number of nerve fibres present in different regions of the acetabular periosteum. The knowledge of regional differences is potentially valuable for the refining of the denervation technique of the hip joint capsule. Thirty canine acetabular fragments were used to compare the nerve fibre density of the periosteum. The results showed a significant difference between the mean density of nerve fibres at the cranial and dorsal-lateral portion (approximately 75 fibres/mm(2)) and caudal lateral portion (approximately 60 fibres/mm(2)) of the acetabulum. Those fibres at the pedosteum are almost positioned in a sagittal plane, pointing towards the joint capsule, suggesting the some density in the latter region. These results indicate a new approach to the articular denervation technique, thus obtanining even better results for the treatment of hip dysplasia in dogs.

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The complete genome sequence of wild-type rabies virus (RABV) isolated from a wild Brazilian hoary fox (Dusicyon sp.), the BR-Pfx1 isolate, was determined and compared with fixed RABV strains. The genome structure and organization of the BR-Pfx1 isolate were composed of 11,924 nt and included the five standard genes of rhabdoviruses. Sequences of mRNA start and stop signals for transcription were highly conserved among all structural protein genes of the BR-Pfx1 isolate. All amino acid residues in the glycoprotein (G) gene associated with pathogenicity were retained in the BR-Pfx1 isolate, while unique amino acid substitutions were found in antigenic region I of the nucleoprotein gene and III of G. These results suggest that although the standard genome structure and organization of the RABV isolate are common between the BR-Pfx1 isolate and fixed RABV strains, the unique amino acid substitutions in functional sites of the BR-Pfx1 isolate may result in different biological characteristics from fixed RABV strains.

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Tonic immobility behavior (TI) is an innate response characterized by profound motor inhibition that is exhibited by prey when physical contact with a predator is prolonged and the situation inescapable. The periaqueductal gray matter (PAG) is intimately associated with the somatic and autonomic components of defensive reactions. This study investigated whether the TI response was able to recruit specific functional columns of the PAG by examining c-fos immunolocalization in guinea pigs. In the TI group, the innate response was invoked in animals through inversion and physical contention for at least 15 min. In the control group, the animals were physically manipulated only. Our results demonstrate that the defensive behavior of TI is capable of promoting the expression of Fos protein in different areas of the PAG, with higher levels of staining in the ventrolateral (vI) and lateral (I) columns. In addition, our results demonstrate increased Fos immunoreactivity (FOS-IR) in the dorsal raphe nucleus, the Edinger-Westphal nucleus, the cuneiform nucleus and the superior colliculus. In contrast, there were no significant alterations in the number of FOS-IR cells in the inferior colliculus or the oculomotor nucleus. Analysis of the results suggests that neuronal activation after the TI response differs by functional column of the PAG. (C) 2010 Elsevier B.V. All rights reserved.

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Spinal cord injury (SCI) causes motor and sensory deficits that impair functional performance, and significantly impacts life expectancy and quality. Animal models provide a good opportunity to test therapeutic strategies in vivo. C57BL/6 mice were subjected to laminectomy at T9 and compression with a vascular clip (30 g force, 1 min). Two groups were analyzed: injured group (SCI, n = 33) and laminectomy only (Sham, n = 15). Locomotor behavior (Basso mouse scale-BMS and global mobility) was assessed weekly. Morphological analyses were performed by LM and EM. The Sham group did not show any morphofunctional alteration. All SCI animals showed flaccid paralysis 24 h after injury. with subsequent improvement. The BMS score of the SCI group improved until the intermediate phase (2.037 +/- 1.198): the Sham animals maintained the highest BMS score (8.981 +/- 0.056). p < 0.001 during the entire time. The locomotor speed was slower in the SCI animals (5.581 +/- 0.871) than in the Sham animals (15.80 +/- 1.166), p < 0.001. Morphological analysis of the SCI group showed, in the acute phase, edema, hemorrhage, multiple cavities, fiber degeneration, cell death and demyelination. In the chronic phase we observed glial scarring, neuron death, and remyelination of spared axons by oligodendrocytes and Schwann cells. In conclusion, we established a simple, reliable, and inexpensive clip compression model in mice, with functional and morphological reproducibility and good validity. The availability of producing reliable injuries with appropriate outcome measures represents great potential for studies involving cellular mechanisms of primary injury and repair after traumatic SCI. (C) 2008 Elsevier B.V. All rights reserved.

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Map algebra is a data model and simple functional notation to study the distribution and patterns of spatial phenomena. It uses a uniform representation of space as discrete grids, which are organized into layers. This paper discusses extensions to map algebra to handle neighborhood operations with a new data type called a template. Templates provide general windowing operations on grids to enable spatial models for cellular automata, mathematical morphology, and local spatial statistics. A programming language for map algebra that incorporates templates and special processing constructs is described. The programming language is called MapScript. Example program scripts are presented to perform diverse and interesting neighborhood analysis for descriptive, model-based and processed-based analysis.

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Objective. The aim of this study was to determine the function of primitive hematopoietic stem cells (PHSC) at phases G(0) and G(1) of the cell cycle. Materials and Methods. A combination of supravital dyes rhodamine123 (Rh), Hoechst33342 (Ho), and pyronin (PY) was used to isolate the G(0) and G(1) subsets of PHSC. A competitive repopulation assay was used to evaluate their in vivo function. Results. We confirmed that the Rh(lo)Lin(-)Kit(+)Sca-1(+) PHSC were relatively quiescent when compared with the more mature Rh(hi)Lin(-)Kit(+)Sca-1 HSC and Rh(hi)Lin(-)Kit(+)Sca-1(-) progenitors. In addition, cells with Rh(lo)Lin(-)Kit(+)Sca-1(+), Rh(lo)Ho(lo)Lin(-)Sca-1(+), or Rh(lo)Ho(sp)Lin(-)Sca-1(+) phenotypes identified the same cell population. We further subfractionated the Rh(lo)Ho(lo/sp)Lin(-)Sca-1(+) PHSC using PY into PYlo and PYhi subsets. Limiting dilution analysis revealed that the frequency of long-term in vivo competitive repopulating units (CRU) of the (PYRhHolo/sp)-Rh-lo-Ho-lo PHSC was 1 in 10 cells, whereas there was at least a three-fold lower frequency in those isolated at the G(1) phase (PYhi) We found a dose-dependent PY-mediated cytotoxicity that at moderate concentration affected most of the murine hematopoietic compartment but spared the early HSC compartment. Conclusion. Our data confirm that the HSC compartment is hierarchically ordered on the basis of quiescence and further extend this concept to PY-mediated cytotoxicity. PY supravital dye can be used to reveal functional heterogeneity within the (RhHolosp)-Ho-lo PHSC population but is of limited use in dissecting the relatively more mature hematopoietic stem/progenitor cell population. (C) 2001 International Society for Experimental Hematology. Published by Elsevier Science Inc.

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The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

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An important feature of improving lattice gas models and classical isotherms is the incorporation of a pore size dependent capacity, which has hitherto been overlooked. In this paper, we develop a model for predicting the temperature dependent variation in capacity with pore size. The model is based on the analysis of a lattice gas model using a density functional theory approach at the close packed limit. Fluid-fluid and solid-fluid interactions are modeled by the Lennard-Jones 12-6 potential and Steele's 10-4-3, potential respectively. The capacity of methane in a slit-shaped carbon pore is calculated from the characteristic parameters of the unit cell, which are extracted by minimizing the grand potential of the unit cell. The capacities predicted by the proposed model are in good agreement with those obtained from grand canonical Monte Carlo simulation, for pores that can accommodate up to three adsorbed layers. Single particle and pair distributions exhibit characteristic features that correspond to the sequence of buckling and rhombic transitions that occur as the slit pore width is increased. The model provides a useful tool to model continuous variation in the microstructure of an adsorbed phase, namely buckling and rhombic transitions, with increasing pore width. (C) 2002 American Institute of Physics.

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In this paper we analyzed the adsorption of gases and vapors on graphitised thermal carbon black by using a modified DFT-lattice theory, in which we assume that the behavior of the first layer in the adsorption film is different from those of second and higher layers. The effects of various parameters on the topology of the adsorption isotherm were first investigated, and the model was then applied in the analysis of adsorption data of numerous substances on carbon black. We have found that the first layer in the adsorption film behaves differently from the second and higher layers in such a way that the adsorbate-adsorbate interaction energy in the first layer is less than that of second and higher layers, and the same is observed for the partition function. Furthermore, the adsorbate-adsorbate and adsorbate-adsorbent interaction energies obtained from the fitting are consistently lower than the corresponding values obtained from the viscosity data and calculated from the Lorentz-Berthelot rule, respectively.

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Transthyretin (TTR) is a 55 kDa protein responsible for the transport of thyroid hormones and retinol in human serum. Misfolded forms of the protein are implicated in the amyloid diseases familial amyloidotic polyneuropathy and senile systemic amyloidosis. Its folding properties and stabilization by ligands are of current interest due to their importance in understanding and combating these diseases. To assist in such studies we developed a method for the solid phase synthesis of the monomeric unit of a TTR analogue and its folding to form a functional 55 kDa tetramer. The monomeric unit of the protein was chemically synthesized in three parts, comprising amino acid residues 151, 5499 and 102127, and ligated using chemoselective thioether ligation chemistry. The synthetic protein was folded and assembled to a tetrameric structure in the presence of the TTRs native ligand, thyroxine, as shown by gel filtration chromatography, native gel electrophoresis, TTR antibody recognition and thyroid hormone binding. In the current study the solution structure of the first of these fragment peptides, TTR(151) is examined to determine its intrinsic propensity to form beta-sheet structure, potentially involved in amyloid fibril formation by TTR. Despite the presence of extensive beta-structure in the native form of the protein, the Nterminal fragment adopts an essentially random coil conformation in solution.

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The aim of the study was to investigate the role of glutamate residue 113 in transmembrane domain 2 of the human noradrenaline transporter in determining cell surface expression and functional activity. This residue is absolutely conserved in all members of the Na+- and Cl--dependent transporter family. Mutations to alanine (hE113A), aspartate (hE113D) and glutamine (hE113Q) were achieved by site-directed mutagenesis and the mutants were expressed in transfected COS-7 or HEK-293 cells. Cell surface expression of IIE113A and hE113D, but not hE113Q, was markedly reduced compared with wild type, and functional noradrenaline uptake was detected only for the hE113Q mutant. The pharmacological properties of the hE113Q mutant showed very little change compared with wild type, except for a decrease in V-max values for noradrenaline and dopamine uptake of 2-3-fold. However, the hE113D mutant showed very marked changes in its properties, compared with wild type, with 82-260-fold decreases in the affinities of the substrates, noradrenaline, dopamine and MPP+, and increased Na+ affinity for stimulation of nisoxetine binding. The results of the study show that the size and not the charge of the 113 glutamate residue of the noradrenaline transporter seems to be the most critical factor for maintenance of transporter function and surface expression.