447 research outputs found

    Study of the improved Sf9 transient gene expression process

    Get PDF
    Insect cells have been widely used for the production of recombinant proteins using recombinant baculovirus for gene delivery [1]. To simplify protein production in insect cells, we have previously described a method, based on transient gene expression (TGE) with cultures of suspension-adapted Sf9 cells using polyethylenimine (PEI) for DNA delivery [2]. Expression of GFP has been realized at high efficiency and a tumor necrosis factor receptor-Fc fusion protein (TNFR-Fc) was produced at a level of 40 mg/L. However, the efficiency of the insect cells TGE system has not been studied and further opti- mization may improve protein titers. Here, we studied the efficiency of PEI for plasmid delivery in Sf9 cells

    A comparison of resting state functional magnetic resonance imaging to invasive electrocortical stimulation for sensorimotor mapping in pediatric patients

    Get PDF
    Localizing neurologic function within the brain remains a significant challenge in clinical neurosurgery. Invasive mapping with direct electrocortical stimulation currently is the clinical gold standard but is impractical in young or cognitively delayed patients who are unable to reliably perform tasks. Resting state functional magnetic resonance imaging non-invasively identifies resting state networks without the need for task performance, hence, is well suited to pediatric patients. We compared sensorimotor network localization by resting state fMRI to cortical stimulation sensory and motor mapping in 16 pediatric patients aged 3.1 to 18.6 years. All had medically refractory epilepsy that required invasive electrographic monitoring and stimulation mapping. The resting state fMRI data were analyzed using a previously trained machine learning classifier that has previously been evaluated in adults. We report comparable functional localization by resting state fMRI compared to stimulation mapping. These results provide strong evidence for the utility of resting state functional imaging in the localization of sensorimotor cortex across a wide range of pediatric patients

    On the role of the corpus callosum in interhemispheric functional connectivity in humans

    Get PDF
    Resting state functional connectivity is defined in terms of temporal correlations between physiologic signals, most commonly studied using functional magnetic resonance imaging. Major features of functional connectivity correspond to structural (axonal) connectivity. However, this relation is not one-to-one. Interhemispheric functional connectivity in relation to the corpus callosum presents a case in point. Specifically, several reports have documented nearly intact interhemispheric functional connectivity in individuals in whom the corpus callosum (the major commissure between the hemispheres) never develops. To investigate this question, we assessed functional connectivity before and after surgical section of the corpus callosum in 22 patients with medically refractory epilepsy. Section of the corpus callosum markedly reduced interhemispheric functional connectivity. This effect was more profound in multimodal associative areas in the frontal and parietal lobe than primary regions of sensorimotor and visual function. Moreover, no evidence of recovery was observed in a limited sample in which multiyear, longitudinal follow-up was obtained. Comparison of partial vs. complete callosotomy revealed several effects implying the existence of polysynaptic functional connectivity between remote brain regions. Thus, our results demonstrate that callosal as well as extracallosal anatomical connections play a role in the maintenance of interhemispheric functional connectivity

    Forest pest management on Typic Quartzipsamments: a management dilemma

    Get PDF
    Pine plantations on Typic Quartzipsamments in East Texas are difficult to establish. Forest management options following clearcutting are limited. A eight year regeneration study of the growth and survival of loblolly, Pinus tuedu, L. shortleaf, P. echinutu Mill., slash, P. elliofii Engelm and longleaf pines P. palustris Mill. was conducted to determine optimum tree species and treatments for reforestation; and to recommend practical alternative land uses and management strategies for Typic Quartzipsamrnents. With successful regeneration also comes insects and pathogens. Impacts of the Nantucket pine tip moth, Rhyacioniujkstrunu, (Comstock) the Deodar weevil, Pissodes nernorensis, Germar, Annosus root rot, Heterobusidion unnosusm (Fr: Fr) Bref, fusiform rust, Cronurtizun quercwn (Berk.) Miyabe ex Shirai f. sp. fisiforme (Hedge and N. Hunt) Burdsall and G. Snow and the Texas leaf-cutting ant, Attu texunu, (Buckley) will be discussed in the context of droughty site management
    corecore