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Biomedical subjects

J L Norris

Publications and source records attributed to J L Norris.

At least 19 recordsLinked to original sources
PubMed2003

Visual localization ability influences cross-modal bias.

The ability of a visual signal to influence the localization of an auditory target (i.e., "cross-modal bias") was examined as a function of the spatial disparity between the two stimuli and their absolute locations in space. Three experimental issues were examined: (a) the effect of a spatially disparate visual stimulus on auditory localization judgments; (b) how the ability to localize visual, auditory, and spatially aligned multisensory (visual-auditory) targets is related to cross-modal bias, and (c) the relationship between the magnitude of cross-modal bias and the perception that the two stimuli are spatially "unified" (i.e., originate from the same location). Whereas variability in localization of auditory targets was large and fairly uniform for all tested locations, variability in localizing visual or spatially aligned multisensory targets was much smaller, and increased with increasing distance from the midline. This trend proved to be strongly correlated with biasing effectiveness, for although visual-auditory bias was unexpectedly large in all conditions tested, it decreased progressively (as localization variability increased) with increasing distance from the midline. Thus, central visual stimuli had a substantially greater biasing effect on auditory target localization than did more peripheral visual stimuli. It was also apparent that cross-modal bias decreased as the degree of visual-auditory disparity increased. Consequently, the greatest visual-auditory biases were obtained with small disparities at central locations. In all cases, the magnitude of these biases covaried with judgments of spatial unity. The results suggest that functional properties of the visual system play the predominant role in determining these visual-auditory interactions and that cross-modal biases can be substantially greater than previously noted.

Adult↗
PubMed1999

Oncogenic Ras enhances NF-kappaB transcriptional activity through Raf-dependent and Raf-independent mitogen-activated protein kinase signaling pathways.

Tumors frequently contain mutations in ras genes, resulting in constitutive activation of Ras-activated signaling pathways. The ultimate targets of these signal transduction cascades are transcription factors required for cellular proliferation. Understanding how constitutive activation of Ras contributes to tumorigenesis requires an understanding of both the signaling pathways that Ras activates and how these pathways in turn regulate gene expression. Gene expression from kappaB sites is enhanced in cells transformed with activated Ras and NF-kappaB activity is required for oncogenic Ras to transform NIH-3T3 and Rat-1 fibroblasts. Both dominant negative and constitutively active components of signaling pathways have been tested for their ability to regulate NF-kappaB. These experiments show that Ras utilizes Raf-dependent and Raf-independent pathways to activate NF-kappaB transcriptional activity, both of which require the stress-activated kinase p38 or a related kinase. In the case of Raf, activation of NF-kappaB by an autocrine factor stimulates kappaB-dependent transcriptional activity.

3T3 Cells↗
PubMed1997

Oncogenic Ha-Ras-induced signaling activates NF-kappaB transcriptional activity, which is required for cellular transformation.

Ras proteins function in stimulating cell proliferation and differentiation through the activation of Raf-dependent and Raf-independent signal transduction pathways and the subsequent activation of specific transcription factors. The transcription factor NF-kappaB has been widely studied as a regulator of genes involved in immune and inflammatory responses. A variety of stimuli activate NF-kappaB through the induced phosphorylation and degradation of the inhibitor IkappaB followed by nuclear translocation of NF-kappaB. We show here that oncogenic forms of Ha-Ras activate NF-kappaB, not through induced nuclear translocation, but rather through the activation of the transcriptional function of the NF-kappaB RelA/p65 subunit. Importantly, RelA/p65 -/- cells are inefficient in the activation of kappaB-dependent gene expression in response to oncogenic Ras expression. Furthermore, IkappaBalpha expression blocks focus formation in NIH3T3 cells induced by oncogenic Ras. These results demonstrate that NF-kappaB is a critical downstream mediator of Ha-Ras signaling and oncogenic potential.

3T3 Cells↗
PubMed1997

Metacarpal and metatarsal fractures in dogs.

Metacarpal fractures were more common than metatarsal fractures in this retrospective study of 37 dogs. Fractures of one metacarpal or metatarsal bone occurred in 24 per cent of the dogs, two metacarpal bones in 16 per cent, three metacarpal or metatarsal bones in 19 per cent, and four metacarpal or metatarsal bones in 41 per cent. Eighty-seven per cent of the dogs with fractures of four bones had fracture displacement or malalignment of at least one digit. Progressive fracture healing usually occurred irrespective of stabilisation method. For malaligned fractures, however, external coaptation did not consistently improve alignment. Fracture alignment was consistently improved by open reduction and internal fixation of acute fractures with bone plates. Fractures of four bones occurred most often in the distal metacarpus as opposed to the proximal metatarsus. Therefore, open reduction and internal fixation may be more commonly indicated for severe metacarpal fractures, because fracture displacement or axial malalignment was significantly associated with fractures of the mid or distal regions of the metacarpus or metatarsus (P = 0.052).

Animals↗
PubMed1996

Functional interactions between the pelle kinase, Toll receptor, and tube suggest a mechanism for activation of dorsal.

A complex signal transduction pathway functions in the early Drosophila embryo to establish dorsal-ventral polarity. Activation of this pathway results in the nuclear transport of the protein dorsal (dl), a member of the rel/NF-kappaB family of transcription factors. Genetic studies have identified three intracellular components whose activity is required for activation of dl: Toll, a transmembrane receptor; pelle (pll), a serine/threonine protein kinase; and tube, a protein of unknown function. Here we examine the activities of these proteins when coexpressed in Drosophila Schneider cells. Coexpression of pll with dl enhanced dl nuclear localization and resulted in a modest increase in transcriptional activity. However, when pll was coexpressed with a specific mutant derivative of Toll (TlNaeI), although not with wild-type Toll, a striking synergistic activation of dl was detected. Unexpectedly, coexpression of pll plus TlNaeI, in the absence of dl, resulted in a similar synergistic activation of a GAL4-tube fusion protein. Based on these and other results, we propose a model in which pll receives a signal from activated Toll and phosphorylates tube, which then participates directly in dl activation.

Animals↗
PubMed1996

A naturalistic study of the impact of acute physical activity on feeling states and affect in women.

This field study used experience sampling procedures to examine the relationship of feeling states and affect to acute bouts of physical activity in women. Participants (N = 86) completed brief affect and feeling state measures (a) in response to random stratified pager tones and (b) before and after acute bouts of vigorous physical activity for 6 weeks. Analysis of averaged difference scores revealed that acute vigorous physical activity was associated with significant improvements in affect and feeling states, particularly in feelings of revitalization. Moreover, within-subject analyses indicated that the effects were moderated by preactivity scores, with the greatest improvements seen when women felt worst before activity.

Adult↗
PubMed1995

Regulation of dorsal in cultured cells by Toll and tube: tube function involves a novel mechanism.

We described previously a transient cotransfection assay that allows us to study regulation of the Drosophila Dorsal protein (dl) in cultured cells. For example, we showed that over-expression of the Toll transmembrane receptor was sufficient to cause relocalization of dl from the cytoplasm to the nucleus. Here we present data that the tube protein, shown previously by genetic studies to act downstream of Toll, can function in a novel way to enhance dl activity. In the absence of dl, or when dl is cytoplasmic, tube is also found in the cytoplasm of transfected cells. But when dl is localized to the nucleus, so is tube. tube can then function to enhance reporter gene expression, either by cooperation with dl or as a GAL4-tube fusion protein. tube thus appears capable of acting both as a chaperon or escort for dl as it moves to the nucleus, and then as a transcriptional coactivator. We also show that the intracytoplasmic domain of Toll, and specifically the region sharing homology with the interleukin-1 receptor, is sufficient to induce dl-tube nuclear translocation.

Animals↗
PubMed1995

Effects of baseline responses, in-task feelings, and duration of activity on exercise-induced feeling states in women.

This study investigated the hypothesis that the effects of acute aerobic exercise on feeling states may be influenced by the objective dose of activity, subjective responses during exercise, and preexisting levels of feeling states. College-age women (N = 80) completed baseline measures and were then randomly assigned to 1 of 4 conditions: attention control for 10 min, or exercise for 10 min, 25 min, or 40 min. Levels of exertion and affect were assessed during exercise, and posttesting occurred 20 min following activity. Exercise enhanced revitalization in comparison with the control condition; however, this effect occurred only for participants scoring low to moderate on the pretest. In addition, in-task feeling states predicted postexercise revitalization even after we controlled for the treatment, the pretest, and the Pretest x Treatment interaction.

Adolescent↗
PubMed1994

Fire safety in the operating room.

The operating room environment is considered a potentially significant fire hazard. The role of the anesthetist in preventing and handling fires is pivotal to patient survival. Means of preventing fires as well as extinguishing them are discussed.

Fires↗
PubMed1992

Selective nuclear transport of the Drosophila morphogen dorsal can be established by a signaling pathway involving the transmembrane protein Toll and protein kinase A.

Establishment of dorsal-ventral polarity in the early Drosophila embryo requires a concentration gradient of the maternal morphogen dorsal (dl). This concentration gradient is established by selective nuclear transport of dl so that dl protein is present only in ventral nuclei. The activity of 11 genes is required for dl nuclear localization. One of these genes, Toll, encodes a transmembrane protein that appears to play the most direct role in regulating dl localization. We have examined the effects of Toll on dl in cotransfected Schneider cells to gain insight into the nature of the interaction between these proteins. We have found that Toll can enhance the nuclear localization of dl and, independently, the ability of dl to activate transcription once in the nucleus. We present evidence that the signaling pathway from Toll to dl involves protein kinase A (PKA) and that nuclear transport and activation of dl results from phosphorylation of dl by PKA. We discuss the significance of these results with respect both to Drosophila embryogenesis and to the regulation of the mammalian transcription factor NF-kappa B.

Animals↗
PubMed1985

Bimanual endoscopic orbital biopsy. An emerging technique.

Diagnostic biopsy specimens from six posterior orbital lesions have been obtained under direct endoscopic view with either a fine needle aspiration or an intracannular microbiopsy forcep. This method is comparable to earlier fine needle aspiration techniques, but has the decided advantage of providing a specimen from visually indentified abnormal tissue. In those cases where inadequate specimens are obtained by fine needle aspiration, a microforcep is used to obtain a substantial specimen. The microinvasive endoscopic biopsy technique of the Orbital Unit at Pacific Medical Center is described with an analysis of six cases. The emerging technology of fiberoptic illumination, minified color video cameras, sophisticated imaging, efficient microsurgical instruments and laser delivery methods make the potential for deep orbital endoscopic microinvasive surgery exciting.

Aged↗
PubMed1983

Autosomal dominant exudative vitreoretinopathy.

Eight family members had familial exudative vitreoretinopathy. They exhibited a variety of clinical stages of the disease process. Some clinical findings included retinal detachment, fibrovascular masses with dragged disc and macula, neovascular fronds and intraretinal deposits. The fundus and angiographic findings were found to be similar to those in cases reported previously. Electroretinograms were normal. Of particular interest in this pedigree was the sole clinical finding of isolated intraretinal deposits in four family members. This characteristic may represent a mild expression of the disease and warrant appropriate genetic counseling. Our study confirms the variable clinical expression of the disease.

Adult↗
PubMed1982

Intraocular foreign body removal by endoscopy.

Pars plana endoscopy was used to guide removal of a large nonmagnetic intraocular foreign body from an eye with corneal scarring and irregularity of such a degree the view through the operating microscope was not adequate to permit such surgery.

Adolescent↗