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27 preschool children were observed naturally during classroom activities. Observations of behaviors of Social Interaction, Spatial Localization, and Posture categories were made under music (folk or rock and roll) and no music conditions. Music selections favored child-to-child social interaction.
Cataract prevention, delay, or reversal requires in vivo detection of lens changes that initiate the opacification process. The determination of lenticular biochemistry by a noninvasive methodology would represent a major step in the in vivo assessment of lens normalcy. Nuclear magnetic resonance spectroscopy appears to be a promising noninvasive technique to meet this goal. However, the correlation of lenticular "invasive" morphological and physiological data with NMR spectroscopic data in organ culture is necessary for establishing the validity of NMR spectral measurements as an index of lens functional integrity. The implementation of lenticular NMR spectroscopic studies will provide quantitative information such as intralenticular pH, Na+ and K+ ion distributions, lenticular levels of phosphorus-containing metabolites, glycolytic pathway intermediates and the end product lactate, sorbitol pathway activity, and possibly reduced glutathione levels. Development in surface coil NMR spectroscopy which enables the spatial localization of tissue metabolites and advances in the refinements required for quantitation of these results are discussed. These measurements of in vivo lenticular biochemistry will provide the information necessary for the scheduling of anticataract drug therapy as well as an ongoing method for monitoring the efficacy of such treatment.
In experiments designed to study the co-adjuvant action of interleukin-2, a model antigen (tetanus toxoid) was passively entrapped in, or covalently coupled to multilamellar liposomes in the presence or absence of interleukin-2 (IL-2). When present, IL-2 was either co-entrapped with the toxoid, entrapped alone in liposomes with toxoid coupled to their surface, or coupled to the surface of liposomes with entrapped toxoid. The role of spatial localization of IL-2 within the liposomal structure (vis a vis that of the toxoid) was studied in terms of its immunoadjuvant action in vivo. Male CD-1 mice were injected intramuscularly twice with a variety of toxoid-containing liposomal preparations in the absence or presence of IL-2 incorporated in the same liposomes as above. In some experiments mice were immunized with liposomal toxoid mixed with separately entrapped IL-2. Results show that IL-2 augments significantly secondary immune responses (IgG1, IgGa, IgG2b subclasses) against the liposomal toxoid (up to 15-fold compared with the liposomal toxoid alone), regardless of cytokine and antigen mode of accommodation in the liposomal structure but only when both are present in the same vesicles. It is suggested that liposomal IL-2 may prove useful as a co-adjuvant for vaccines which are weak or ineffective.
OBJECT: After traumatic brain injury (TBI), S100B protein is released by astrocytes. Furthermore, cerebrospinal fluid (CSF) and serum S100B levels have been correlated to outcome. Given that no data exist about the temporal profile of cerebral S100B levels following TBI and their correlation to serum levels, the authors examined whether proton magnetic resonance (MR) spectroscopy is capable of measuring S100B. METHODS: Results of in vitro proton MR spectroscopy experiments (2.35-tesla magnet, 25 G/cm, point-resolved spatially localized spectroscopy) revealed an Sl00B-specific peak at 4.5 ppm and confirmed a positive correlation between different S100B concentrations (10 nM-1 microM) and the area under the curve (AUC) for the S100B peak (r = 0.991, p < 0.001). Thereafter, proton MR spectroscopy was performed in male Sprague-Dawley rats (7 X 5 X 5-mm voxel in each hemisphere, TR 3000 msec, TE 30 msec, 256 acquisitions). Exogenously increased CSF S100B levels (approximately 200 ng/ml) through the intraventricular infusion of S100B increased the AUC of the S100B peak from 0.06 +/- 0.02 to 0.44 +/- 0.06 (p < 0.05), whereas serum S100B levels remained normal. Two hours after lateral fluid-percussion injury, serum S100B levels increased to 0.61 +/- 0.09 ng/ml (p < 0.01) and rapidly returned to normal levels, whereas the AUC of the S100B peak increased to 0.19 +/- 0.04 at 2 hours postinjury and 0.41 +/- 0.07 (p < 0.05) on Day 5 postinjury. CONCLUSIONS: Proton MR spectroscopy proves a strong correlation between the AUC of the S100B peak and S100B concentrations. Following experimental TBI, serum S100B levels increased for only a very short period, whereas cerebral S100B levels were increased up to Day 5 postinjury. Given that experimental data indicate that S100B is actively released following TBI, proton MR spectroscopy may represent a new tool to identify increased cerebral S100B levels in patients after injury, thus allowing its biological function to be better understood.
OBJECT: The authors conducted a study to determine age-related changes in expression of transforming growth factor (TGF)-beta1, -beta2, -beta3, and Type I and Type II receptors in various cells in the nucleus pulposus and anulus fibrosus. Immunolocalization of TGFbetas and Type I and II receptors was examined during the aging process of cervical intervertebral discs in senescence-accelerated mice (SAM). The TGFbeta family has important roles for cellular function of various tissues. Its role in disc aging, however, is unknown. Detailed information on the temporal and spatial localization of TGFbetas and their receptors in discs is required before discussing introduction of them clinically into the intervertebral disc. METHODS: Three groups of five SAM each were used. The groups of SAM were age 8, 24, and 50 weeks, respectively. Hematoxylin and eosin staining and immunohistochemical study involving specific antibodies for TGFbeta1, -beta2, -beta3, and Types I and II TGF receptors were performed. Intervertebral discs exhibited degenerative change with advancing age. The TGFbetas and their receptors were present in the fibrocartilaginous cells within the anulus fibrosus and notochord-like cells within the nucleus pulposus of young mice. Expression of TGFbetas and Type I and Type II receptors changed markedly in the cells within the anulus fibrosus during the aging process. CONCLUSIONS: The TGFbetas and their receptors were present in cells within the nucleus pulposus and the anulus fibrosus of young mice, and their expression decreased with age.
Visual marking is a mechanism by which new visual stimuli can gain a selection advantage by the top-down attentional inhibition of stimuli already in the field. Previous work (Olivers, Watson, & Humphreys, 1999) has shown that, for moving stimuli, there must be a unique feature difference between the old items and the new items for marking to occur. The present study shows that this constraint is not necessary if the local spatial relationships between the old moving items remain constant. It is proposed that, with a fixed configuration, the old moving items can be grouped to form a single object. An inhibitory template set up to represent the object then coordinates the application of inhibition to the individual stimuli. Implications for the theory and ecological flexibility of visual marking are discussed.
Three experiments examined sequential effects in choice reaction time tasks. On each trial, a right/left positional judgment was made to a either a pure tone or a luminance increment in a visual array of box elements. In the first two experiments, a preparatory signal was presented prior to each imperative signal to indicate the relevant stimulus modality. At a short stimulus onset asynchrony (SOA) between the preparatory and the imperative signal (i.e., 60 msec), subjects were quicker to repeat the same response than to change their response when presented with successive tones, although no such repetition effect occurred on the visual target trials. Subjects were impaired if the stimulus modality changed across successive trials regardless of the modality of the target. At a longer SOA (i.e., 500 msec), these sequential effects were abolished; subjects were assumed to be able to prepare for the relevant modality because of the presentation of the preparatory signal. When the preparatory signals were omitted, in a final experiment, the modality-switching costs were still evident, but now inhibition of return occurred on both the auditory and the visual target trials-subjects were now impaired in responding when the target reappeared at its immediately previous location. It seems, therefore, that the repetition effect and modality-switching effects do dissociate. The data revealed clear differences between orienting attention to a particular spatial locale and focusing attention to a particular sensory modality.
Experiments were performed to assess the response of the human visual system to dynamic random-dot patterns composed of disparity mixtures. In Experiment 1, the perceived depth and relative stability of two patterns were compared; one pattern depicted two transparent layers of dots, and the other depicted a volume of dots. Two effects were found: (1) the volume pattern exhibited a large degree of disparity averaging; and (2) asymmetries were observed in the relative stability of these two patterns. Experiment 2 was designed to determine whether these findings could be attributed to spatially localized processes occurring at the location of disparity discontinuities. This was accomplished by introducing unpaired noise points localized either along the disparity discontinuities or in the center of the layered and volume patterns. The amount of depth averaging and the direction of the asymmetry did not appear to depend on processes localized along the disparity discontinuities. Results of these experiments, taken in conjunction with those of previous studies, suggest that hysteresis is independent of cooperative persistence mechanisms.
Recently, quantitative models based on signal detection theory have been successfully applied to the prediction of human accuracy in visual search for a target that differs from distractors along a single attribute (feature search). The present paper extends these models for visual search accuracy to multidimensional search displays in which the target differs from the distractors along more than one feature dimension (conjunction, disjunction, and triple conjunction displays). The model assumes that each element in the display elicits a noisy representation for each of the relevant feature dimensions. The observer combines the representations across feature dimensions to obtain a single decision variable, and the stimulus with the maximum value determines the response. The model accurately predicts human experimental data on visual search accuracy in conjunctions and disjunctions of contrast and orientation. The model accounts for performance degradation without resorting to a limited-capacity spatially localized and temporally serial mechanism by which to bind information across feature dimensions.
Mycobacterium tuberculosis (M.tb) is a leading cause of global infectious mortality. The pathogenesis of tuberculosis involves inhibition of phagosome maturation, leading to survival of M.tb within human macrophages. A key determinant is M.tb-induced inhibition of macrophage sphingosine kinase (SK) activity, which normally induces Ca2+ signaling and phagosome maturation. Our objective was to determine the spatial localization of SK during phagocytosis and its inhibition by M.tb. Stimulation of SK activity by killed M.tb, live Staphylococcus aureus, or latex beads was associated with translocation of cytosolic SK1 to the phagosome membrane. In contrast, SK1 did not associate with phagosomes containing live M.tb. To characterize the mechanism of phagosomal translocation, live cell confocal microscopy was used to compare the localization of wild-type SK1, catalytically inactive SK1G82D, and a phosphorylation-defective mutant that does not undergo plasma membrane translocation (SK1S225A). The magnitude and kinetics of translocation of SK1G82D and SK1S225A to latex bead phagosomes were indistinguishable from those of wild-type SK1, indicating that novel determinants regulate the association of SK1 with nascent phagosomes. These data are consistent with a model in which M.tb inhibits both the activation and phagosomal translocation of SK1 to block the localized Ca2+ transients required for phagosome maturation.
Chronic pain often differs from acute pain. The correlation between tissue pathology and the perceived severity of the chronic pain experience is poor or even absent. Furthermore, the sharp spatial localization of acute pain is not a feature of chronic pain; chronic pain is more diffuse and often spreads to areas beyond the original site. Of importance, chronic pain seldom responds to the therapeutic measures that are successful in treating acute pain. Physicians who are unaware of these differences may label the patient with chronic pain as being neurotic or even a malingerer. During the past decade, an exponential growth has occurred in the scientific underpinnings of chronic pain states. In particular, the concept of nonnociceptive pain has been refined at a physiologic, structural, and molecular level. This review focuses on this new body of knowledge, with particular reference to the chronic pain state termed "fibromyalgia."
The spatial expression of carrot (Daucus carota L.) top1 genes encoding the two isoforms of the enzyme DNA topoisomerase I (EC 5.99.1.2) was investigated. In situ hybridization analysis performed with a probe recognizing both top1 transcripts provided evidence that in explanted hypocotyls induced to proliferate in vitro by the addition of the growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D), the mRNA accumulation parallels the proliferation of provascular cells of the stelar cylinder. During somatic embryogenesis, the histological distribution of top1 transcripts was strongly evident at the stage of torpedo-shaped embryos, but gene expression was not only restricted to meristematic regions. When the spatial localization was extended to carrot vegetative apices and the investigation was carried out with specific probes for top1alpha and top1beta, both transcripts preferentially accumulated in tissues having mitotic activity.
Spiral waves are though to be the underlying mechanism of re-entrant ventricular and atrial tachycardias. In such cases, one is generally interested in eliminating spiral wave activity from the medium. In this paper, solve a cubic FitzHugh-Nagumo system of PDEs is solved in two dimensions with initial conditions such that a spiral wave is formed at the center of a rectangular grid. Then the effect of a spatially-localized step-like periodic forcing placed at different positions around the spiral tip is studied. Due to this forcing, the tip begins to drift away from the perturbation in a direction that depends on their relative location. By shifting successively the location of the perturbation relative to that of the tip strategy is developed which it is possible to pursuit the spiral wave away from the center of the grid accelerating its drift with every shift of the perturbation.
Spatially localized Ca(2+) domains are thought to play a key role in action potential (AP)-evoked neurotransmitter release at fast synapses. We used a stage-scan confocal spot-detection method and the low-affinity Ca(2+) indicator Oregon Green 488 BAPTA-5N to study the spatiotemporal profile of presynaptic AP-induced Ca(2+) domains. Families of scanned AP-induced fluorescence transients were detected from spot locations separated by 200-300 nm, within the vicinity of Ca(2+) entry sites. Typically, the largest transient in a particular scan peaked within approximately 1 msec and decayed with rapid (tau(1) of 1.7 msec) and slow components (tau(2) of 16 msec, tau(3) of 78 msec). As the spot was incrementally displaced, transients progressively exhibited a slowing in their time-to-peak and a loss of the fast decay component. Three-dimensional graphs of fluorescence versus time and spot displacement revealed the presence of AP-induced fluorescence domains that dissipated within approximately 7 msec. The size of fluorescence domains were estimated from the full-width at half-maximum of gaussian fits to isochronal DeltaF/F plots and ranged from 0.6 to 3.0 micrometer, with a mean +/- SD of 1.6 +/- 0.6 micrometer. Model simulations of a localized Ca(2+) entry site predicted the major features of the fluorescence transients and suggested that, within approximately 1 msec of the initiation of the Ca(2+) current, both the fluorescence domain and the underlying Ca(2+) domain do not extend significantly beyond the site of entry. Consistent with this prediction, the intracellular addition of EGTA (up to 2 mM) accelerated the decay of the measured transients but did not affect the domain size.
PURPOSE: To determine whether binding of Pseudomonas aeruginosa (P. aeruginosa) to the scarified mouse cornea depends on interaction with proteoglycans (PGs). METHODS: Scarified corneas were treated with anti-proteoglycan monoclonal antibodies (MAbs), glycosaminoglycans (GAGs), heparinase III or chondroitin ABC lyase before inoculation with P. aeruginosa strain ATCC 19660 or PAO1. Scanning electron microscopy (SEM) was used to quantitate adherent bacteria. Frozen sections of unwounded and wounded mouse cornea, the latter treated or not treated with heparinase III were stained to spatially localize perlecan [core protein or heparan sulfate (HS) side chains]. Anti-perlecan MAb against the heparan sulfate proteoglycan core protein and succinyl wheat germ agglutinin (sWGA), a lectin which recognizes N-acetyl-glucosamine in heparan sulfate, respectively were used. RESULTS: Anti-perlecan MAb, as well as heparan sulfate, heparin and heparinase III decreased the binding of both bacterial strains to cornea, and the decrease was concentration-dependent. Fluorescence microscopic analysis of sections of mouse cornea immunostained with anti-perlecan MAb showed that perlecan was localized to the epithelial basement membrane. Scarification of the mouse cornea exposed perlecan in the basement membrane and increased bacterial binding to this site was consistent with this exposure. Lectin staining revealed that heparinase treatment removed heparan sulfate side chains of perlecan from the exposed basement membrane, and this removal was consistent with a decrease in bacterial binding. CONCLUSIONS: These studies provide evidence that perlecan, core protein and its heparan sulfate side chains serve as a binding site for Pseudomonas aeruginosa when the basement membrane of the cornea is exposed.
In situ hybridization (ISH) is the demonstration of specific genetic information within a morphologic context. For HPV, colorimetric ISH has the advantage that it can be applied to routine formalin-fixed paraffin embedded tissues. This conserves patient material and permits histologic selection of optimal material for testing. ISH allows for precise spatial localization of viral sequences within tissues. ISH also allows the integration status of HPV to be determined. The major limitations of the method are the potential for error in HPV typing because of probe cross-hybridization and relatively low sensitivity if the method is not fully optimized.
Spatial localization and time of expression of glial, neurospecific, and extracellular antigens were studied during retina regeneration in adult newts using antibodies against the glial acidic fibrillar protein (GFAP), neurospecific molecules (N-CAM and PSA-N-CAM), and tenascin (Tn). At the early stages of regeneration (5th day after the operation), slightly differentiated cells in the retina growth area, which are not cellular sources of regeneration, were brightly stained by the antibodies. The one-two-layered retina rudiment formed from the pigment epithelium layer a week later was also intensely stained by the antibodies to GFAP. The retina rudiment cells belong to slightly differentiated precursors of the regenerating retina. It was first shown that the antibodies to GFAP were not only markers of the glial cells, but also markers of slightly differentiated precursors of the regenerating retina. Expression of neurospecific antigens was found in depigmented cells of the retina rudiment. It appeared to have been initiated by cell interactions in the regenerate. An expression of tenascin was found in the cells migrating in the eye cavity and contacting with the retina rudiment cells. The role of tenascin in interaction with the retina rudiment is unknown.
Laparoscopic surgery has numerous advantages, but this technique is difficult and requires specific training. This paper presents a simulator for gynecologic laparoscopic surgery called S.P.I.C. (Pedagogical Simulator for Gynecologic Laparoscopic Surgery), specifically designed for teaching. It includes a rail with 3 trocars already in place, and a computer monitor. Training using the simulator is divided into tasks and steps in order of increasing difficulty. Each step consists of training exercises and evaluations. Learning with the simulator is guided by software that allows instructors to personalize their lessons. This prototype has allowed us to put into place training for spatial localization and manipulation of surgical instruments in the abdominal cavity. An evaluation at a clinical site has allowed us to determine the improvements to be made on this prototype. Training with a simulator is part of a resident's regular curriculum and is not meant to replace on site hospital experience. Some imperfections in imaging still exist, due to inevitable technical limitations. Our initial choice was to emphasize realism and "real time", rather than the "aesthetic quality" of the images. Furthermore, by limiting our graphic expectations, we have been able to create a simulator at a reasonable overall price. The S.P.I.C. training tool remains experimental and is still in the process of being developed.