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Results for “Integrative interaction”

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At least 307 records · Page 17Linked to original sources

PubMed1997

How neural interactions form neural responses in the salamander retina.

A wide range of experimental data characterizing properties of individual salamander retinal cells and synaptic interactions are integrated to form a quantitative computational model of visual function in the salamander retina. The model is used to show how specific interactions between neurons and between networks of neurons can lead-to the integrated response behavior of individual cells deep in the retina. The model is also used to illustrate how the representation of moving and stationary stimuli is encoded in a series of layer-by-layer transformations leading to the final retinal output at the ganglion cell layer.

Animals↗

PubMed2003

An integrated strategy for sustainable forest-energy-environment interactions in Nigeria.

The Nigerian forests have been subjected to unguarded exploitation over the years. Although there is overwhelming empirical evidence, which show that Nigeria's forest, may soon vanish, available statistics have shown its increasing importance in the energy sector. With increasing population come the attendant demands on the biotic environment through increased land clearing, deforestation, devegetation, decertification, with attendant soil erosion, flooding, sand dune formation, and changes in the micro-climate with consequent loss of biological productivity and associated socio-economic and socio-political problems in the country. There is therefore the need to adopt measures that will shift the attention of the Nigerian populace from the forest to satisfy their energy needs. However, such measures that will address the challenges confronting the forestry, forest-based energy systems and the environment should be consistent with the development needs, resources and priorities of the nation. Hence, for sustainable forest-energy-environment interactions, a holistic and integrated strategy that can be adopted to minimise the observed forest depletion must take cognisance of options from various land use practices, energy and forest sectors. The focus of this paper is on a strategy of options from both the energy and forest sectors. Based on the socio-economic, socio-political and environmental analyses of various options from the energy and forest sectors, the philosophy behind the mosaic approach to sustainable development has been considered in developing the proposed strategy. Policy measures to implement this strategy of options in the national development programs are also suggested.

Conservation of Energy Resources↗

PubMedDate not supplied

The use of automated assessment with seriously mentally ill clients.

Despite the skepticism of many behavioral healthcare practitioners that their clients are "much too ill" to interact positively with a computer-based assessment system, this article describes a successful program that integrates computerized interactions for seriously mentally ill adults into its overall information management. At the core of this information system is a 30- to 45-minute assessment using eight basic scales plus clinical data. According to a satisfaction survey, clients generally are quite open to interacting with the computer--when it is presented as an adjunct to the work of clinicians.

Ambulatory Care Information Systems↗

PubMed2006

Lagged covariance structure models for studying functional connectivity in the brain.

Most cognitive processes are supported by large networks of brain regions. To describe the operation of these networks, it is critical to understand how individual areas are functionally connected. Here, we establish a statistical framework for studying effective and functional brain connectivity, using data obtained with a relatively new neuroimaging method, the event-related optical signal (EROS). The novelty of our approach is the use of timing information (in the form of lagged cross-correlations) in interpreting the connections between areas. Interpretation of lagged cross-correlations exploits the combination of spatial and temporal resolution provided by EROS. In this paper, we apply dynamic factor analysis as a method for testing various structural models on the lagged covariance matrices derived from the EROS data. We first illustrate the approach by testing a simple path model of neural activity propagation from area V1 to V3 in a visual stimulation task. We then build more complex structural equation models with latent variables, describing both within-hemisphere integrity, and interactions between the two hemispheres, to interpret data from a second task involving inter-hemispheric competition. The results demonstrate how the integrity of anatomical connections between the two hemispheres explains different patterns of cross-hemispheric interactions. This approach allows for fitting brain imaging data to complex models that capture dynamic cognitive processes as they rapidly evolve over time.

Adolescent↗

PubMed2002

Calpain as an effector of the Gq signaling pathway for inhibition of Wnt/beta -catenin-regulated cell proliferation.

Signaling pathways interact to integrate and regulate information flow in evoking complex cellular responses. We have studied the mechanisms and consequences of interactions between the Gq and Wnt/beta-catenin pathways. In human colon carcinoma SW480 cells, activation of the Gq pathway inhibits beta-catenin signaling as determined by transcriptional reporter and cell proliferation assays. Ca(2+) release from internal stores results in nuclear export and calpain-mediated degradation of beta-catenin in the cytoplasm. Galphaq does not inhibit the effects of constitutively activated DeltaN-XTCF3-VP16 chimera in SW480 cells. Similarly, in HEK293 cells the Gq pathway suppresses beta-catenin-T cell factor/lymphocyte enhancer factor-1 transcriptional activity induced by Wnt/Frizzled interaction or glycogen synthase kinase-3beta-resistant beta-catenin, but not DeltaN-XTCF3-VP16. We conclude that Gq signaling promotes nuclear export and calpain-mediated degradation of beta-catenin, which therefore contributes to the inhibition of Wnt/beta-catenin pathway.

Calcium↗

PubMed1997

The thiol-dependent reductase ERp57 interacts specifically with N-glycosylated integral membrane proteins.

The lumen of the endoplasmic reticulum contains a number of distinct molecular chaperones and folding factors, which modulate the folding and assembly of newly synthesized proteins and protein complexes. A subset of these luminal components are specific for glycoproteins, and, like calnexin and calreticulin, the thiol-dependent reductase ERp57 has been shown to interact specifically with soluble secretory proteins bearing N-linked carbohydrate. Calnexin and calreticulin also interact with glycosylated integral membrane proteins, and in this study we have examined the interaction of ERp57 with these substrates. As with soluble proteins, the binding of ERp57 to an integral membrane protein is dependent upon the protein bearing an N-glycan that has undergone glucose trimming. Furthermore, ERp57 binds to newly synthesized glycoproteins in combination with either calnexin or calreticulin. We propose that ERp57 acts in concert with calnexin and calreticulin to modulate glycoprotein folding and enforce the glycoprotein specific quality control mechanism operating in the endoplasmic reticulum.

Animals↗

PubMed1992

Promoting social interaction of children with disabilities in integrated preschools: a failure to generalize.

In this study, the Classwide Social Skills Program (CSSP) was introduced for all children in four integrated preschool classes, and generalization of effects was measured across settings and over time for 14 children with disabilities between the ages of 3 and 5 years. Results indicated that the CSSP increased the positive play of children with disabilities to levels comparable to classmates without disabilities. Levels of teacher reinforcement toward the children with disabilities increased as well. These increases in teacher and child behaviors, however, did not generalize to 3- or 6-month follow-up periods nor to another play session in the day. Implications for promoting social interaction in integrated preschool settings are discussed.

Behavior Therapy↗

PubMed2001

Essential components of antimicrobial gastrointestinal epithelial barrier: specific interaction of mucin with an integral apical membrane protein of gastric mucosa.

BACKGROUND: The gastric mucosal protective barrier consists of two essential elements: mucus glycoprotein, mucin, secreted by gastric mucosal cells, and the mucin binding protein (MBP), an integral component of the apical epithelial membrane. The studies described here provide evidence on the structure of MBP, its interaction with mucin, and the susceptibility to phospholipase C (PLC) and Helicobacter pylori protease. MATERIAL AND METHODS: The rat gastric mucosa was used to isolate mucin and the apical epithelial membranes. A buffered saline extract of the mucosal cells was used for the isolation of mucin and the 1% Triton X-100-insoluble gastric apical membranes for the preparation of MBP. RESULTS: The studies on MBP, the mucosal mucin receptor revealed that the protein is anchored in apical membrane through glycosylphosphatidylinositol (GPI). The deamination of MBP with nitrous acid afforded phosphatidylinositols (PIs) and a water soluble, 97 kDa glycosylated protein. The in situ studies with untreated rat gastric mucosa and the mucosa depleted of mucin showed that MBP without mucin was susceptible to the proteolytic degradation with pepsin and H. pylori proteases, but was not released from the apical membrane by the treatment with bacterial PLC. CONCLUSION: The study of carbohydrate ligands for MBP revealed binding of octa- and decasaccharides of gastric mucin. The severe impairment in mucin adhesion to MBP, induced by the diet containing ethanol, supports the conclusion that specific carbohydrate determinants participate in mucin attachment to MBP and epigenetic control of the processes that coordinates its interaction with apical mucosal epithelium in the formation of innate protective barrier.

Animals↗

PubMedDate not supplied

Integrated hormonal-immunological-vascular (H-I-V triad) systems interactions in the rheumatic diseases.

An expanded paradigm for the diffuse rheumatic diseases is presented which focuses upon the integrated interactions of hormonal, immunological and vascular systems, i.e. the "H-I-V" triad. The reciprocal interactions between the (neuro)hormonal and immunological systems are increasingly recognized in experimental models and human examples of these diseases. Other important two-way interactions, e.g. between the hormonal and vascular systems, are also believed to be operating, but are relatively unexplored at present. An overview of the triad interactions between these vital regulatory systems of the body is offered. These interactions are further influenced by their relationships to broader genetic controls, physiological modulators, and environmental influences. Earlier, physiopathogenic stages of these evolving rheumatic disorders need to be understood, if prevention and optimal healing are to be achieved in the future.

Autoimmunity↗

PubMed1995

Effect of hydrodynamic interactions on the diffusion of integral membrane proteins: tracer diffusion in organelle and reconstituted membranes.

A persistent discrepancy exists between theoretical predictions and experimental observations for the diffusion coefficients of integral membrane proteins in lipid bilayers free of immobilized proteins. Current thermodynamic theories overestimate tracer diffusion coefficients at high area fractions. We explore the hypothesis that the combined effect of hydrodynamic and thermodynamic interactions reconciles theory with experiment. We have determined previously the short- and long-time tracer diffusivities, Ds and Dl, respectively, of integral membrane proteins in lipid bilayers as a function of their area fraction, phi. The results are based on two-particle hydrodynamic and thermodynamic interactions and are precise to O(phi). Here we extend the results for Dl to high phi by combining the hydrodynamic results for Ds into theories for Dl based on many-particle thermodynamic interactions. The results compare favorably with the experimental measurements of Dl as a function of protein area fraction for bacteriorhodopsin in reconstituted membranes and for complex III of the mitochondrial inner membrane. The agreement suggests that both hydrodynamic and thermodynamic interactions are important determinants of diffusion coefficients of proteins in lipid bilayers. Additional experiments are required to verify the role of hydrodynamic interactions in protein diffusion in reconstituted systems.

Bacteriorhodopsins↗

PubMed2005

Multisensory spatial interactions: a window onto functional integration in the human brain.

Incoming signals from different sensory modalities are initially processed in separate brain regions. But because these different signals can arise from common events or objects in the external world, integration between them can be useful. Such integration is subject to spatial and temporal constraints, presumably because a common source is more likely for information arising from around the same place and time. This review focuses on recent neuroimaging data concerning spatial aspects of multisensory integration in the human brain. These findings indicate not only that multisensory integration involves anatomical convergence from sensory-specific ('unimodal') cortices into multisensory ('heteromodal') brain areas, but also that multisensory spatial interactions can affect even so-called 'unimodal' brain regions. Such findings call for a revision of traditional assumptions about multisensory processing in the brain.

Brain↗

PubMed2004

VisANT: an online visualization and analysis tool for biological interaction data.

BACKGROUND: New techniques for determining relationships between biomolecules of all types--genes, proteins, noncoding DNA, metabolites and small molecules--are now making a substantial contribution to the widely discussed explosion of facts about the cell. The data generated by these techniques promote a picture of the cell as an interconnected information network, with molecular components linked with one another in topologies that can encode and represent many features of cellular function. This networked view of biology brings the potential for systematic understanding of living molecular systems. RESULTS: We present VisANT, an application for integrating biomolecular interaction data into a cohesive, graphical interface. This software features a multi-tiered architecture for data flexibility, separating back-end modules for data retrieval from a front-end visualization and analysis package. VisANT is a freely available, open-source tool for researchers, and offers an online interface for a large range of published data sets on biomolecular interactions, including those entered by users. This system is integrated with standard databases for organized annotation, including GenBank, KEGG and SwissProt. VisANT is a Java-based, platform-independent tool suitable for a wide range of biological applications, including studies of pathways, gene regulation and systems biology. CONCLUSION: VisANT has been developed to provide interactive visual mining of biological interaction data sets. The new software provides a general tool for mining and visualizing such data in the context of sequence, pathway, structure, and associated annotations. Interaction and predicted association data can be combined, overlaid, manipulated and analyzed using a variety of built-in functions. VisANT is available at http://visant.bu.edu.

Animals↗

PubMed2002

Dynamic analysis of beat-to-beat fetal heart rate variability recorded by SQUID magnetometer: quantification of sympatho-vagal balance.

BACKGROUND: Quantitative analysis of fetal heart rate variability (HRV) can be used to investigate the neural control mechanisms of fetal cardiac activity. However, conventional power spectrum methods do not reveal the full complexity of the time-varying sympatho-vagal balance in the fetus. AIM: This study was carried out to explore alternative digital signal processing methods of analysing fetal HRV in time domain (rather than frequency domain), in line with most types of physiological monitoring. METHODS: The beat-to-beat fetal heart rate was obtained by Superconducting Quantum Interference Device (SQUID) magnetocardiographic recording. These data were filtered within appropriately selected frequency bands: high frequency (HF) f>0.2 Hz, low frequency (LF) 0.05<f<0.2 Hz and very low frequency (VLF) f<0.05 Hz. To quantify the dynamics of sympathetic-parasympathetic interaction, the integrated amplitude of the HF curve (within a moving 4-s time window) was compared with the LF component. Also, the interaction of the VLF component with both HF and LF components was analysed. RESULTS: A high degree of correlation was observed between these components for extended periods of time, although the presence of a strong correlation was found to depend on the fetal behavioural state. It was further observed that the low-frequency oscillations lag high-frequency activity by 1-3 s. CONCLUSIONS: We propose a numerical parameter, based on the ratio of the LF to HF components of the fetal HRV as a quantitative measure of the relative gain of the parasympathetic system. Our results show this parameter to decrease with gestational age of the fetus.

Female↗

PubMed2006

The electronic mean-field configuration interaction method. I. Theory and integral formulas.

In this article, we introduce a new method for solving the electronic Schrodinger equation. This new method follows the same idea followed by the mean-field configuration interaction method already developed for molecular vibrations; i.e., groups of electronic degrees of freedom are contracted together in the mean field of the other degrees. If the same partition of electronic degrees of freedom is iterated, a self-consistent field method is obtained. Making coarser partitions (i.e., including more degrees in the same groups) and discarding the high energy states, the full configuration interaction limit can be approached. In contrast with the usual group function theory, no strong orthogonality condition is enforced. We have made use of a generalized version of the fundamental formula defining a Hopf algebra structure to derive Hamiltonian and overlap matrix element expressions which respect the group structure of the wave function as well as its fermionic symmetry. These expressions are amenable to a recursive computation.

Journal Article↗

PubMed1985

The statistical interaction of cerebral specialization and integration in the interpretation of dynamic brain images.

Two constructs of brain function, namely cerebral specialization and integration, have been examined in the analysis of blood flow and metabolic function resulting from dynamic imaging procedures. The purpose of the current paper is to illustrate the interaction of these two constructs at the statistical level. Because of the statistical interaction, it is argued that the currently accepted statistical evidence for cerebral specialization is, in fact, partially a function of the degree of regional cerebral integration. Therefore, found asymmetries of flow or rate may be solely a function of cerebral integration. These points are discussed with respect to developing a better understanding of stimulus/brain/behavior relations.

Blood Glucose↗

PubMed2006

The neural cell adhesion molecule NCAM regulates neuritogenesis by multiple mechanisms of interaction.

The neural cell adhesion molecule NCAM and its glycosylation with polysialic acid (polySia) are crucially involved in proliferation, migration and differentiation of neural progenitors. Modification with polySia, homophilic and heterophilic interactions set the function of NCAM, but little is known on their interplay. We have shown recently that removal of polySia induces neuronal differentiation via heterophilic NCAM interactions at cell contacts between SH-SY5Y neuroblastoma cells. Here we analyze the additional impact of NCAM-positive fibroblasts as a ligand-presenting cellular environment, a model often used to demonstrate the neuritogenic effect of homophilic NCAM interactions. Native SH-SY5Y cells did not respond to interactions with fibroblast NCAM. However, after induction of neuronal differentiation by retinoic acid the previously ineffective NCAM signals activated extracellular signal-regulated kinase (ERK) and promoted neuritogenesis. Removal of polySia increased neuritogenesis in retinoic acid-treated cells additive to the NCAM substrate effect. The change in responsiveness to substrate NCAM was associated with a rearrangement of polysialylated NCAM away from its enrichment at homotypic cell-cell contacts and with the appearance of non-polysialylated NCAM, i.e. changes facilitating NCAM interactions with the substrate. Thus, heterophilic and homophilic NCAM interactions are integrated into the cell's response yet they have the capacity to independently trigger neuritogenesis. The actual occurrence of each of these interactions, however, depends on the cellular context, targeted cell surface presentation of NCAM and the dynamic regulation of its modification by polysialic acid. In summary, this study reveals how the complex interplay of NCAM interactions and polysialylation provides an elaborate system to regulate neuritogenesis.

Animals↗

PubMed2004

Effects of feeding endophyte-infected fescue seed on reproductive traits of male mice divergently selected for resistance or susceptibility to fescue toxicosis.

Our objective was to determine whether consumption of endophyte-infected fescue seed affected male reproduction differently in a mouse line previously selected for susceptibility (S) to fescue toxicosis than in a line previously selected for fescue toxicosis resistance (R). For 8 weeks following weaning, 48 males per line were provided diets containing 50% of either endophyte-infected (E+) or endophyte-free (E-) fescue seed. Each male was then paired with a female for 1 week, with litter size and weight recorded from subsequent births. Males were then killed, testes and seminal vesicles were weighed, cauda epididymal sperm were collected and testis cross-sections were fixed. The E+ diet reduced litter size by 0.5 in mates of S males but increased it by 1.0 in mates of R males (line by diet interaction P=0.05). Testis traits were not affected by diet or the line by diet interaction. Sperm integrity was adversely affected by the E+ diet (P<0.01) but did not differ significantly between lines, nor were line by diet interactions important. In earlier work, the E+ diet reduced long-term reproduction by a larger amount in S- than in R-line mated pairs. Because the E+ diet had similar effects on reproductive traits in R and S males in the current experiment, we infer that the differential impact previously reported acted primarily through traits expressed in females.

Animals↗

PubMed2002

Protein interaction verification and functional annotation by integrated analysis of genome-scale data.

Assays capable of determining the properties of thousands of genes in parallel present challenges with regard to accurate data processing and functional annotation. Collections of microarray expression data are applied here to assess the quality of different high-throughput protein interaction data sets. Significant differences are found. Confidence in 973 out of 5342 putative two-hybrid interactions from S. cerevisiae is increased. Besides verification, integration of expression and interaction data is employed to provide functional annotation for over 300 previously uncharacterized genes. The robustness of these approaches is demonstrated by experiments that test the in silico predictions made. This study shows how integration improves the utility of different types of functional genomic data and how well this contributes to functional annotation.

Animals↗