Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “spatial patterning”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed2004

Temporal and spatial patterns of Kv1.1 and Kv1.2 protein and gene expression in spinal cord white matter after acute and chronic spinal cord injury in rats: implications for axonal pathophysiology after neurotrauma.

After spinal cord injury (SCI), surviving white matter axons display axonal dysfunction associated with demyelination and altered K+ channel activity. To clarify the molecular basis of posttraumatic axonal pathophysiology after SCI, we investigated the changes in expression and distribution of the axonal K+ channel subunits Kv1.1 and Kv1.2 in spinal cord white matter after in vivo SCI in the rat. Using Western blot analysis, we found an increased expression of Kv1.1 and Kv1.2 at 2 and 6 weeks after SCI. By real-time PCR we observed an increase in Kv1.1 and Kv1.2 mRNA levels 1 day after SCI, which persisted until 6 weeks. Confocal immunohistochemistry showed a markedly dispersed labelling of Kv1.1 and Kv1.2 along the injured axons, in contrast to the tight localization of these channels to the juxtaparanodes of noninjured axons. This redistribution of Kv1.1 and Kv1.2 occurred as early as 1 h postinjury along some injured axons, and persisted at 6 weeks postinjury. In parallel with the redistribution of Kv1.1 and 1.2, contactin-associated protein (Caspr), which is normally confined to a paranodal location, also displayed a more diffuse distribution along the injured spinal cord axons. Our results suggest that the increased expression of Kv1.1 and Kv1.2 proteins is transcriptionally regulated. In contrast, the redistribution of the axonal K+ channel subunits occurs very early postinjury and probably reflects a disruption of the juxtaparanodal axonal region due to physical trauma, as shown by altered localization of Caspr.

Actins↗
PubMed1988

Spatial patterns in the fruiting bodies of the cellular slime mold Polysphondylium pallidum.

During morphogenesis in the slime mold Polysphondylium pallidum cell masses are periodically pinched off from the base of the developing sorogen. These masses round up and differentiate into secondary sorogens, which become radially ordered arrays of secondary fruiting bodies called whorls. Here we describe the morphogenesis of P. pallidum and characterize the spacing of whorls along the central stalk of the fruiting body and the spacing of sorocarps within whorls. We find both are highly regular. We propose that the linear spacing of whorls can be accounted for satisfactorily by a model that views the periodic release of cell masses from the base of the developing sorogen as the consequence of an imbalance between forces that orient amoebae toward the tip of the culminating sorogen, and cohesive forces between randomly moving cells in the basal region of the sorogen, which act as a retarding force. The orderly arrangement of fruiting bodies within whorls can be explained most easily by models that employ short-range activation and lateral inhibition.

Cell Differentiation↗
PubMed1991

[Spatial pattern and microvascularization of the ductuli efferentes testis of bulls (Bos taurus)].

The arrangement, origin, course and opening of the ductuli efferents testis of the bull (Bos taurus) were visualized using scanning electron microscopy. The corresponding capillary structure was also described and documented with the help of corrosive microanatomical casts. The number of the ductuli efferents testis of the bull varies narrowly between 12 to 13. Ductuli removed from the surrounding tissue have a length of up to 78 cm. The duct system is composed of linear as well as tortuous parts, permitting division into three distinct segments. Blind ending ductules are very short. We therefore do not see these structures as being associated with spermiostasis. The capillary density as well as the capillary architecture show regional peculiarities. All segments of the ductuli efferents testis are composed of capillaries of the continuous type. The findings indicate that the increased capillary density in the voluminous initial section of the ductuli efferents testis represents the basis for resorptive as well as secretory activities in the bull.

Animals↗
PubMed2005

Spatial patterns of gene expression in the extramatrical mycelium and mycorrhizal root tips formed by the ectomycorrhizal fungus Paxillus involutus in association with birch (Betula pendula) seedlings in soil microcosms.

Functional compartmentation of the extramatrical mycelium of ectomycorrhizal (ECM) fungi is considered important for the operation of ECM associations, although the molecular basis is poorly characterized. Global gene expression profiles of mycelium colonizing an ammonium sulphate ((NH4)2SO4) nutrient patch, rhizomorphs and ECM root tips of the Betula pendula-Paxillus involutus association were compared by cDNA microarray analysis. The expression profiles of rhizomorphs and nutrient patch mycelium were similar to each other but distinctly different from that of mycorrhizal tips. Statistical analyses revealed 337 of 1075 fungal genes differentially regulated among these three tissues. Clusters of genes exhibiting distinct expression patterns within specific tissues were identified. Genes implicated in the glutamine synthetase/glutamate synthase (GS/GOGAT) and urea cycles, and the provision of carbon skeletons for ammonium assimilation via beta-oxidation and the glyoxylate cycle, were highly expressed in rhizomorph and nutrient patch mycelium. Genes implicated in vesicular transport, cytoskeleton organization and morphogenesis and protein degradation were also differentially expressed. Differential expression of genes among the extramatrical mycelium and mycorrhizal tips indicates functional specialization of tissues forming ECM associations.

Ammonium Sulfate↗
PubMedDate not supplied

Relationship between spatial pattern of basal bodies and membrane skeleton (epiplasm) during the cell cycle of Tetrahymena: cdaA mutant and anti-membrane skeleton immunostaining.

Microtubular basal bodies and epiplasm (membrane skeleton) are the main components of the cortical skeleton of Tetrahymena. The aim of this report was to study functional interactions of basal bodies and epiplasm during the cell cycle. The cortex of Tetrahymena cells was stained with anti-epiplasm antibody. This staining produced a bright epiplasmic layer with a dark pattern of unstained microtubular structures. The fluorescence of the anti-epiplasm antibody disappeared at sites of newly formed microtubular structures, so the new basal body domains and epiplasmic layer could be followed throughout the cell cycle. Different patterns of deployment of new basal bodies were observed in early and advanced dividers. In advanced dividers the fluorescence of the epiplasmic layer diminished locally within the forming fission line where the polymerization of new basal bodies largely extincted. In wild type Tetrahymena, the completion of the micronuclear metaphase/anaphase transition was associated with a transition from the pattern of new basal body deployment and epiplasm staining of the early divider to the pattern of the advanced dividers. The signal for the fission line formation in Tetrahymena (absent in cdaA1 Tetrahymena mutationally arrested in cytokinesis) brings about 1) transition of patterns of deployment of basal bodies and epiplasmic layer on both sides of the fission line; and 2) coordination of cortical divisional morphogenesis with the micronuclear mitotic cycle.

Animals↗
PubMed1996

Organizing spatial pattern in limb development.

Recent studies on the development of the legs and wings of Drosophila have led to the conclusion that insect limb development is controlled by localized pattern organizing centers, analogous to those identified in vertebrate embryos. Genetic analysis has defined the events that lead to the formation of these organizing centers and has led to the identification of gene products that mediate organizer function. The possibility of homology between vertebrate and insect limbs is considered in light of recently reported similarities in patterns of gene expression and function.

Animals↗
PubMed2000

Relationships between spatial patterns of colonic pressure and individual movements of content.

The aim of this study was to examine the relationship between colonic pressure waves and movement of content. In 11 healthy subjects, pressures were recorded at 10-cm intervals from cecum to rectum for 32 h. In six subjects, transit was simultaneously measured for 8 h after direct cecal instillation of 1.5 mCi of (99m)Tc sulfur colloid. Thirty-two percent of isotope movements were related to nonpropagating activity and twenty-eight percent to propagating sequences. The extent of isotope movement related to propagating sequences (25.1 +/- 2.1 cm) was greater than that due to nonpropagating activity (12.8 +/- 0.7 cm; P = 0.0001). Propagating sequences originated significantly more frequently (P = 0.004) and propagated further (P = 0.0006) in the proximal compared with the distal colon. Only 36% of propagating sequences were propulsive of content, and compared with nonpropulsive sequences, these propagated further (41 +/- 6 vs. 27 +/- 2 cm; P < 0.05) and had a higher probability of originating proximally (P = 0.0003), a higher pressure wave amplitude (50 +/- 5 vs. 34 +/- 4 mmHg; P = 0.0001), and slower velocity (2.2 +/- 0.3 vs. 3.6 +/- 0.47 cm/s; P = 0.02). We conclude that most movements of colonic content are related to pressure waves. There is marked regional variation in the prevalence, velocity, and extent of propagation of propagating pressure wave sequences, which are an important mechanism for transporting content over long distances. The effectiveness of transport by a propagating sequence is influenced by its site of origin, amplitude, and velocity.

Adolescent↗
PubMed1995

Odorant-specific spatial patterns in mucosal activity predict perceptual differences among odorants.

1. Using operant techniques, rats were trained to differentially report (i.e., identify) the odorants propanol, carvone, citral, propyl acetate, and ethylacetoacetate. After acquisition training, the animals were tested using a 5 x 5 confusion matrix design. The results of the behavioral tests were used to measure the degree of perceptual dissimilarity between any pair of odorants. These dissimilarity measures were then subjected to multidimensional scaling analysis to establish a two-dimensional perceptual odor space for each rat. 2. At the completion of behavioral testing, the fluorescence changes in the dye di-4-ANEPPS were monitored on the rat's nasal septum and medial surface of the turbinates in response to the same odorants. For each mucosal surface a 6.0 x 6.0 mm area was sampled at 100 contiguous sites with a 10 x 10 photodiode array. 3. Formal statistical analysis indicated a highly significant predictive relationship between the relative position of an odorant's mucosal loci of maximal activity or "hot spot" and the relative position of the same odorant in a psychophysically determined perceptual odor space (F = 15.6, P < 0.001). 4. The results of this study suggest for the first time that odorant-induced mucosal activity patterns serve as the substrate for the perception of odorant quality.

Animals↗
PubMed1997

Topographical analysis of spatial patterns generated by a cellular automaton model of the proliferation of a cancer cell line in vitro.

A well-suited model to simulate cellular population dynamics is the two-dimensional cellular automaton model, which consists of a lattice of sites, the value ai,j of each site being updated in discrete time steps according to an identical deterministic rule depending on a neighbourhood of sites around it. A cellular automaton is described which mimics cell population proliferation by replacing the site values by the age and the cycle phase of cells. The model takes into account the size of the cells. It is used to simulate the proliferation of the human breast cancer cell line MCF-7 and the results of the simulation are compared with experimental data obtained from a light microscopic image analysis of the proliferation process. The initial configuration of the cellular automaton is obtained from the discretization of the results of the initial stage of the image processing. After each day of proliferation the pattern obtained from the simulation is compared to the experimental result of the corresponding image analysis. The comparison is made from a topographical point of view through the concept of the minimal spanning tree graph. The agreement between experiment and model is a good starting point to complex models such as cell proliferation under growth effectors or drugs.

Breast Neoplasms↗
PubMedDate not supplied

Spatial patterning of colloidal nanoparticle-based thin film by a combinative technique of layer-by-layer self-assembly and lithography.

A novel approach to generating clear patterns of different types of nanoparticles is presented in this paper. Nanoassembly in the vertical direction was combined with planar micropatterning. This provides industrial applications of a popular layer-by-layer method to produce multilayers of polymers, nanoparticles, and proteins organized on the nanometer scale. A thin film of organic polystyrene spheres was first coated on the pretreated silicon wafer with layer-by-layer self-assembly. Then a layer of aluminium was deposited on the thin film. A layer of positive photoresist was spun on the surface of aluminum and then illuminated with UV light. The exposed parts of the resist were removed and windows were opened above the aluminum. The subsequent etching removed exposed aluminium and left a polystyrene thin film in the open windows. Oxygen plasma was employed to remove the polystyrene thin film on the bottom. Eventually, aluminum and photoresist were removed and only the desired pattern remained. This approach was also employed for the patterning of the silica nanoparticle thin film, a widely used material in various applications. In this case, wet etching was demonstrated to etch silica particles. A scanning electron microscope was used to produce the image of the pattern.

Aluminum↗