Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Spatial Analysis”

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 1,063 records · Page 59Linked to original sources
PubMed1972

Qualitative analysis of unilateral spatial neglect in relation to laterality of cerebral lesions.

Two unselected groups of patients, affected by a mono-hemispheric cerebral lesion, were studied in two seperate services by means of various tasks of copying drawings, in order to check the hypothesis of a qualitative difference between unilateral spatial neglect (USN) of right and left brain-damaged patients. In both experimental groups drawing asymmetries were found to be of slight importance among the left hemispheric patients, consisting chiefly in a tendency to omit some figures lying on the right half of the models, and to be definitely more severe in the right braindamaged patients, where the main pattern of USN seemed to be the tendency to leave unfinished the left half of the drawings. A second aim of the study was to describe some less frequent features of USN, sometimes found in patients who were recovering from a severe damage of the minor hemisphere. These patterns of USN seemed to suggest that the core of unilateral spatial neglect consists in a peculiar disorganization of the type of synthesis of the sensory data which seems characteristic of the minor hemisphere.

Apraxias↗
PubMed1992

Flow-induced calcium transients in single endothelial cells: spatial and temporal analysis.

Endothelial cells (EC) are uniquely situated to respond to hemodynamic forces. Because flow-mediated release of endothelial-derived relaxing factors is associated with increased EC intracellular calcium ([Ca2+]i), we sought to determine the effects of fluid shear stress on EC [Ca2+]i. Cells were subjected to flow in parallel-plate flow chambers and glass capillary tubes, and single cell [Ca2+]i was measured using fura-2. Upon initiation of flow (shear stress of 30 dyn/cm2), [Ca2+]i increased within 30 s to a peak value (approximately 4 times basal) and then decreased slowly to a plateau (approximately 2 times basal) that persisted for greater than 5 min. A striking finding was that the increases in [Ca2+]i were nonhomogeneous; the nuclear region and a periplasma membrane region were higher than the cytosol. After flow cessation, the increase in [Ca2+]i could be elicited repeatedly by resumption of flow. Removing extracellular Ca2+ did not eliminate the response. In contrast to EC, rat aortic smooth muscle cells showed no flow-mediated increase in [Ca2+]i. The complexity of EC [Ca2+]i response to flow suggests regulation of [Ca2+]i by several mechanisms that may serve a role in both short- and long-term EC responses to flow.

Animals↗
PubMed2026

Spatial Mapping of the Precancer-to-Cancer Transition in Breast and Prostate.

UNLABELLED: Breast and prostate cancers are both hormone-driven adenocarcinomas that undergo analogous invasion programs. Using lightsheet microscopy on intact tumors, we identified transitional junctions between precancerous and invasive regions. We then developed a multimodal serial-section workflow integrating volumetric reconstruction with spatial transcriptomics. Analysis of 319 spatial assays from 51 cases revealed gene expression features and novel structural insights defining the shift from precancer to invasive disease. In breast cancer, loss of MGP and PLAT was associated with invasive transition and promoted tumorigenesis in functional assays. In prostate cancer, GDF15, ALDH1A3, ANPEP, and FASN were upregulated along invasive progression, and their knockdown in PC-3 cells suppressed proliferation and migration. Enrichment of tumor-associated macrophages (SPP1+ and MS4A6A+) along non-triple-negative breast cancer breast cancer transitions highlights immune involvement as a potential driver of invasiveness. SIGNIFICANCE: Our method of defining precise spatial locations of invasive transition allows for the direct interrogation of transition drivers, presenting new therapeutic targets for the two most prevalent cancers and providing a framework for studying spatially defined mechanisms of tumor progression. See related commentary by Jing and Li, p. 1720.

Humans↗
PubMed2006

Spatially filtered magnetoencephalographic analysis of cortical oscillatory changes in basic brain rhythms during the Japanese 'Shiritori' Word Generation Task.

BACKGROUND: 'Shiritori' (capping verses) is a traditional Japanese word generation game, and is very familiar to native Japanese speakers. The shiritori task is expected to more strongly activate temporal language-related regions than conventional word generation to letters because of its characteristic way to make cue letters. OBJECTIVES: The aim of this study was to examine the cortical oscillatory changes in basic brain rhythms during silently performing a shiritori task. METHODS: Using synthetic aperture magnetometry (SAM) analysis of magnetoencephalography, we estimated the tomographic distributions of the statistically significant differences of the power in the alpha and beta frequency bands between the resting and the task periods. RESULTS: Significant event-related desynchronization (ERD) in the 8- to 25-Hz band, thought to reflect neural activation, was localized within task-related cortical regions with left-side dominance. The significant ERDs were estimated in both the frontal and temporal language-related regions encompassing Broca's and Wernicke's areas, although previous neuroimaging studies using word generation to letters showed neural activation predominantly in frontal regions. CONCLUSIONS: Our results show the potential of SAM analysis for reliable brain mapping of language processing, and suggest that the shiritori task might be more suitable for examining the language-related network in the brain than conventional word generation to letters.

Adult↗
PubMed1997

Cellular dynamics in early atherosclerotic lesion progression in white carneau pigeons. Spatial and temporal analysis of monocyte and smooth muscle invasion of the intima.

The early stages of atherosclerosis are characterized by macrophage invasion of the intimal space and proliferation of smooth muscle cells (SMCs). In this study, we characterize the timing and location of each of these processes. Dividing cells of the developing lesions were labeled with [3H]thymidine at different times during lesion progression. Comparable stages of lesion development were analyzed, with the only variable being the length of time between labeling and necropsy. In this way, the mechanism by which lesion composition changes could be inferred from changes in the distribution of label over time. When cells were labeled just before necropsy, serial sections showed monocyte influx predominantly occurring at lesion edges and resulting in a labeling index of 27%. Near the lesion edge, medial SMCs were not stimulated to proliferate. In contrast, in more central areas of the lesion, monocyte influx and intimal SMC proliferation were minimal. Medial SMC proliferation in central regions, however, was high, with a labeling index of 20% in the upper media. Over time, proliferating medial SMCs migrated into the intimal lesion but did not migrate laterally to any great extent. This migration pattern maintained precise subdomains during lesion development, with each domain representing a different stage of lesion development. The edge of lesions thus represents very early events, central regions indicate later events, and intermediate regions provide information about stages between these extremes.

Animals↗
PubMed1988

Discrete analysis of spatial-sensitivity models.

The visual representation of spatial patterns begins with a series of linear transformations: the stimulus is blurred by the optics, spatially sampled by the photoreceptor array, spatially pooled by the ganglion-cell receptive fields, and so forth. Models of human spatial-pattern vision commonly summarize the initial transformations by a single linear transformation that maps the stimulus into an array of sensor responses. Some components of the initial linear transformations (e.g., lens blurring, photoreceptor sampling) have been estimated empirically; others have not. A computable model must include some assumptions concerning the unknown components of the initial linear encoding. Even a modest sketch of the initial visual encoding requires the specification of a large number of sensors, making the calculations required for performance predictions quite large. We describe procedures for reducing the computational burden of current models of spatial vision that ensure that the simplifications are consistent with the predictions of the complete model. We also describe a method for using pattern-sensitivity measurements to estimate the initial linear transformation. The method is based on the assumption that detection performance is monotonic with the vector length of the sensor responses. We show how contrast-threshold data can be used to estimate the linear transformation needed to characterize threshold performance.

Humans↗
PubMed2006

Lethal risk to birds from insecticide use in the United States--a spatial and temporal analysis.

We used pesticide use data and previously published models to estimate the lethal risk to birds from insecticides used in U.S. agriculture. Data from the U.S. Department of Agriculture's National Agricultural Statistical Service (NASS, Washington, D.C.) were used to assess how the lethal risk to birds has changed over the period 1991 to 2003 and to compare risk among crop types according to the most recently available surveys. Because the NASS data coverage is incomplete, both with respect to crop and state, we also used a database assembled by the National Center for Food and Agriculture Policy (NCFAP, Washington, D.C.) for the 1997 reference year, to which we added state-specific average application rates for crop/insecticide combinations. For each state/crop/insecticide combination (>6000 entries), we assessed the proportion of crop area on which avian mortality was deemed probable, as well as the extended number of hectares this represented. The crops responsible for most potential bird mortality in the United States were corn and cotton, followed more distantly by alfalfa, wheat, potato, peanut, sugar beet, sorghum, tobacco, and citrus. Other crops represented a higher risk to birds on a per hectare basis. The southeast United States generally had the highest proportion of farmland with a lethal risk to birds. On a positive note, the lethal risk to birds has generally declined over the last decade in most crops, although there are exceptions such as small fruit crops. The reasons for this improvement vary from crop to crop, but usually entail the replacement of older more hazardous products with newer ones with lower acute toxicity to birds.

Animals↗
PubMed1986

Development and analysis of a spatial visualization test for middle school boys and girls.

The development of a paper-and-pencil spatial-visualization test for middle school students is reported. The test consists of 32 multiple-choice items of 10 different types. The basic figures for the stimuli and the responses for the items vary from flat views, to numerical data, to corner views of "buildings" constructed from small cubes. The test was administered to a sample of 674 boys and 676 girls in Grades 5 through 8 from three sites representing a broad range of socioeconomic background. The reliability coefficients for various groups of students ranged from .72 to .86. The test-retest reliability coefficient for 73 students was .79. Site, grade, and sex differences, consistent with many other reports, were found. For additional 582 students in Grades 8 to 12 at two sites scores correlated .61 and .66 with scores of the Differential Aptitude Space Relations Test.

Child↗
PubMed1995

Mechanisms in retinal vasculogenesis: an analysis of the spatial branching site correlation.

Starting from fractal dimension calculations of retinal vessel patterns, different growth models and related mechanisms have been suggested to simulate retinal vasculogenesis. A comprehensive view of this topic does not exist. In order to elucidate this question the spatial correlation of the vessel branching sites of the embryonic vessel pattern has been studied. During development of the retinal vasculature within the nerve fiber layer a modification of the branching characteristics can be observed. This result supports theories which suggest a close relation between the vessel propagation and the structure and surface characteristics of the invading vascular cells and the retinal tissue. Arterio-venous differentiation, however, may be dominated by diffusion processes.

Animals↗
PubMedDate not supplied

[Comparative analysis of the spatial organization of myoglobins. I. Hydrophobicity profiles].

Hydrophobicity profiles of myoglobins in the animal species far remote in the evolutionary series are considerably similar. A complete coincidence as to the arrangement of hydrophobic zones along the polypeptide chain in myoglobins of the compared species (from a man to mollusc) is revealed at the beginning of alpha-helix of B-segment and in the area corresponding to a cluster which embodies a heme- bound water molecule, distal histidine E7 being directed to this cluster. The mollusc myoglobin with two absent (as compared to myoglobins of other species) hydrophobic sites differs in the profile of hydrophobicity most of all. It is supposed that hydrophobic nuclei forming the heme circumference create a globule "skeleton" thus pre-setting general spatial structure of the myoglobin molecule, which is very significant for its functional activity.

Alligators and Crocodiles↗
PubMed2003

[Analysis on instantaneous spatial pattern of thermal force field in Harbin].

The spatial pattern of urban thermal force field is not only the dominant content in assessing city ecological environment, but also an important base for city green system planning. The status of spatial pattern of thermal force field in Harbin was analyzed with RS and GIS techniques. Based on the instantaneous radiation temperature of the land surfaces in the city when the TM image was sensed remotely, all the patches were divided into 3 levels, i.e., low radiation temperature (< 10 degrees C), middle radiation temperature (10-22 degrees C), and high radiation temperature of the land surfaces (22-31 degrees C). The patches with high radiation temperature accounted for 61%, those with low radiation temperature accounted for 17%, and those with middle radiation temperature accounted for 22%. 7018 patches (12,252 hm2 in total) with super-thermal radiation (> 28 degrees C) were uneven in their areas. The biggest area in these patches was 1489 hm2, and the smallest one was 0.72 hm2. The proportion of the patches with an area less than 1 hm2, between 1-5 hm2, and more than 5 hm2 was 95.02%, 3.46%, and 1.58%, respectively. There were 3 types of spatial patterns of the super-thermal radiation patches, i.e., round form (the average radiation temperature was 30.8 degrees C), ring form (the average radiation temperature was 27 degrees C), and pieces form (the average radiation temperature was 24.7 degrees C). Daowai District and Daoli District were round form, districts along the ring routes of railway in the city were ring form, and Nangang District and Dongli District were pieces form. Some advices to resolve the problem of 'heat island effect' influenced by the factors including greenland covering rate, greenland area and building dimension were discussed.

City Planning↗
PubMedDate not supplied

[Comparative analysis of EEG spatial organization in the rats with different level of genetically determinated anxiety under ethanol].

The pecularities of EEG changes in the rats with geneticaly different level of anxiety was studed after ethanol injection. The biopotentials spatial synchronization and entropy in the "high anxious" rats (strain MR) did not increase under low dose; on the contrary the above changes were characteristic for the rats without anxiety signs (strain MNRA). After injection of middle and high ethanol doses the "high anxious" rats as compared with "low anxious" ones had the "simplification" of reaction type--the increase of narrow frequency coherence (i.e. linear biopotentials relationship) and spectral power of theta-activity (5.75-7.25 Hz), which was combined with the decrease of nonlinear biopotential characteristics. This fact is interpreted as the predominance of subcortical mechanisms of the brain functional state regulation over cortical ones. The significant decrease of high frequency EEG components in "high anxious" rats takes place under more high ethanol doses, presumably reflecting the increase of the anxiolytic level of ethanol effect.

Animals↗
PubMedDate not supplied

[Computer analysis of the spatial structure of the amphotericin channel].

Energy of Amphotericin B cholesterol complex in a membrane was calculated by the method of atom--atomic potentials. The complex is shown to have two stable states. One of them is stabilized by electrostatic interactions between charged groups of neighbouring antibiotic molecules due to a decline of the molecules to the pore radius. Another state with radial orientation of antibiotic molecules and smaller pore diameter is stabilized mainly by van-der-Waals forces. A conclusion is made that transitions between open and closed states may result from small shifts and turn of all the antibiotic molecules in the complex.

Amphotericin B↗