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Results for “spatial patterning”

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At least 1,009 records · Page 56Linked to original sources
PubMed1995

Velocity profile distribution along an arterial vessel: way to improve detection of stenotic sites.

The influence of an arterial stenosis on the pattern of blood velocity spatial distribution is investigated. The blood velocity field in a human femoral artery in a stenotic state is computed by means of numerical simulation. Four distributions of velocity profiles along the vessel are shown, corresponding to four different instants of the cardiac cycle. The shape of the spatial pattern of the velocity profile is strongly perturbed by the stenosis: disturbances are so clear that an easy, precise localisation of the stenotic site is always possible, whatever instant of the cardiac cycle is considered. The reported results prove that a three-dimensional view of the velocity profile distribution along the vessel best emphasises the relevant haemodynamic information from a diagnostic point of view.

Arterial Occlusive Diseases↗
PubMed2002

Developmental and spatial expression pattern of syntaxin 13 in the mouse central nervous system.

Vesicular transport involves SNARE (soluble- N-ethylmaleimide-sensitive-factor-attachment-protein-receptor) proteins on transport vesicles and on target membranes. Syntaxin 13 is a SNARE enriched in brain, associated with recycling endosomes; its overexpression in PC12 cells promotes neurite outgrowth. This suggests an important role for receptor recycling during neuronal differentiation. Here we describe the spatiotemporal pattern of syntaxin 13 expression during mouse brain development. During early embryogenesis (E12-E15), it was found in the forebrain ventricular zone and in primary motor and sensory neurons in the brainstem, spinal cord and sensory ganglia. In the forebrain at E15, syntaxin 13 was not detected in neuroblasts in the intermediate zone of the embryonic hemispheric wall, while there was labeling in cortical neurons in deeper layers starting at E15-18, and progressively in later-generated neurons up to layer II around P6. Syntaxin 13 reached maximal expression in all brain divisions at about P7, followed by a decrease, with heterogeneous neuron populations displaying various staining intensities in adult brain. While usually restricted to the soma of neurons, we transiently detected syntaxin 13 in dendrites of pyramidal neurons during the first postnatal week. In conclusion, the developmentally regulated syntaxin 13 expression in various neuronal populations is consistent with its involvement in endocytic trafficking and neurite outgrowth.

Aging↗
PubMed1991

Two-dimensional gel electrophoresis of human lens epithelium: a study of spatial protein patterns and aging.

The polypeptides in portions of human lens epithelium from individuals of various ages were resolved by two-dimensional (2D) gel electrophoresis. The epithelium was divided into a central area of 12.5 mm2, a surrounding area of 50.2 mm2, and an area which was outside of this region. The proteins were solubilized in urea and run on gels to determine if differences existed in the major polypeptides of the lens epithelium with regard to position in the lens as well as if differences might occur with age. The patterns obtained were remarkably similar in regions of the epithelium examined. The results also demonstrated that the composition of the major polypeptides were not substantially altered in the adult epithelium with age. Two-dimensional gels of proteins from a 3-month-old specimen prepared in a manner similar to that used during extracapsular cataract extraction were also similar to the other samples; however, this sample contained slightly increased staining of proteins greater than 30 kD.

Adult↗
PubMed1992

Effects of contrast substitutions upon motion detection in spatially random patterns.

We report the effects of contrast changes between frames in a random-square kinematogram. When the contrasts of both frames are too low to permit directional discrimination, increasing the contrast of either the first or the second frame alone makes directional discrimination possible. However, at suprathreshold contrasts for motion detection, increasing the contrast of either the first or the second frame alone makes discrimination more difficult. We conclude that motion detection is a special case of contrast discrimination, in agreement with the Reichardt model of motion detection.

Contrast Sensitivity↗
PubMed1994

Xenopus laevis cellular retinoic acid-binding protein: temporal and spatial expression pattern during early embryogenesis.

There is increasing evidence that retinoic acid (RA) has a role in establishing normal axial patterns during Xenopus laevis embryo-genesis. Several types of retinoid binding proteins are thought to mediate the effects of RA. We report the isolation of a cDNA, named xCRABP-b, which encodes a X. laevis cellular retinoic acid-binding protein (xCRABP). This cDNA hybridises to a transcript in gastrular stage embryos of approximately 3 kb, much larger than those CRABP transcripts expressed in mice. The expression of the xCRABP mRNA is generally restricted to tissues which are sensitive to the teratogenic effects of excess RA. It is likely, that during normal X. laevis embryogenesis, concentrations of RA in RA-responsive cells are modulated by the xCRABP gene product.

Amino Acid Sequence↗
PubMed2005

Temporal and spatial expression pattern of beta1 sodium channel subunit during heart development.

OBJECTIVES: The aim of this study is to analyze Scn1b mRNA expression levels and protein distribution of Scn1b, a putative modulator of the pore-forming Na(+) channel subunit in the heart, during mouse cardiac development. METHODS: Scn1b mRNA levels were determined by real-time RT-PCR using embryonic hearts ranging from E9.5 to E18.5 as well as in postnatal and adult heart. Scn1b protein distribution and subcellular localization during cardiogenesis were analyzed by immunohistochemistry and confocal microscopy. RESULTS: Scn1b mRNA showed a dynamic expression pattern, peaking at stage E12.5 and decreasing at E15.5. Scn1b mRNA increased at later embryonic and neonatal stages, being maximal in the adult heart. Immunohistochemistry experiments revealed comparable distribution of Scn1b protein between the different cardiac chambers at early embryonic stages. With further development, Scn1b protein showed an enhanced expression in the trabeculated myocardium and the bundle branches. At the subcellular level in later embryonic and postnatal mouse cardiomyocytes, Scn1b was present in T-tubules as identified by immunostaining of alpha-actinin, and in the intercalated disks as identified by immunostaining of connexin 43. CONCLUSION: These results demonstrate that Scn1b is expressed during mouse heart development, suggesting it can play an important role in the action potential configuration of the cardiomyocytes during heart morphogenesis.

Aging↗
PubMed2006

The temporal and spatial expression pattern of myosin Va, Vb and VI in the mouse ovary.

There are 16 classes of unconventional myosins. Class V myosins have been shown to be involved in transporting cargo to and from the cell periphery. Class VI myosins have also been shown to transport cargo from the cell periphery, although it seems that these proteins have many roles which include the mediation of cell migration and stereocillia stabilisation. With the requirement of myosin VI for Drosophila oogenesis, the localised expression of Myosin V in the developing egg chamber and recent mounting evidence which links myosin VI to the migration of human ovarian cancer cell lines, we wanted to investigate the expression pattern of these two myosin classes in the normal mouse ovary. Here we show that these myosins are expressed, localised and regulated within the oocyte and granulosa cells of the developing mouse follicle.

Animals↗
PubMed1997

Further evidence of abnormal cytoarchitecture of the entorhinal cortex in schizophrenia using spatial point pattern analyses.

Previous studies have reported cytoarchitectural abnormalities in superficial laminae of rostral portions of the entorhinal cortex in schizophrenia, including decreased densities of neurons, poorly formed layer II neuron islands, and apparent displacement of layer II-type neurons deep into layer III; however, findings have been controversial, given the qualitative nature of the descriptions and the normal heterogeneity of cytoarchitecture of the region. The x, y coordinates of Nissl-stained neurons were mapped in layers II, III, and V of entorhinal subdivision ER in 8 prospectively accrued patients with schizophrenia and 8 nonneuropsychiatric controls. Indices of neuron dispersion, nearest neighbor distances, and effective radius were determined. An abnormally clustered dispersion of neurons in layer III was present in schizophrenics compared to controls along with a reduced neuron effective radius, whereas the mean nearest-neighbor distance was normal. In layer II, there was a significantly increased effective radius, whereas other indices were normal. No between-group differences were noted in layer V for any variable. These data provide further evidence for subtle aberrant cytoarchitecture in superficial laminae of the entorhinal cortex in schizophrenia and are consistent with neurodevelopmental models of abnormal neuronal pruning, "miswiring," and/or migration in the illness.

Aged↗
PubMed1995

Patterns of spatial functioning in Turner's syndrome.

This paper presents results from a study of task performance on a variety of spatial tasks in 9-11 year-old children with Turner's Syndrome (T.S.), divided into those with genotype 45XO and those with Mixed genotypes, including isochromosomes of X and mosaicism. There was a significant overall effect of group reflecting impaired spatial cognition in T.S. with greater decrement in the 45XO group. Further investigation of the significant group by task interaction indicated that the group effects appeared on a visuo-perceptual task and on three visuo-constructional tasks but that there were no specific deficits in the T.S. groups on visuo-spatial or tactile-spatial tasks. In T.S., visuo-perceptual and visuo-constructive sub-systems of spatial skill may be more vulnerable than other components of spatial cognition, to the neuro-biological influences which contribute to the disorder. Such dissociation supports theories of modularity in the development of spatial skill. The spatial tasks which create difficulty overlap only partially with those for which there are sex differences amongst normal children and do not represent a simple exaggeration of normal male-female differences.

Child↗