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101.
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Belichenko PV Brown D Jeffrey M Fraser JR 《Neuropathology and applied neurobiology》2000,26(2):143-149
Neurone damage and eventual loss may underlie the clinical signs of disease in the transmissible spongiform encephalopathies (TSEs). Although neurone death appears to be through apoptosis, the trigger for this form of cell death in the TSEs is not known. Using two different murine scrapie models, hippocampal pyramidal cells were studied through microinjection of fluorescent dye, and synaptic integrity, using p38-immunoreactivity (p38-IR), both visualized using confocal laser scanning microscopy. Intradendritic distensions and dendritic spine loss were found to co-localize to areas of vacuolar and prion protein pathology in the hippocampus of mice infected with ME7 or 87 V scrapie. A significant reduction in p38-IR was found concomitantly in the hippocampus in ME7 scrapie mice. These results indicate that both pre- and post-synaptic sites are altered by scrapie infection; this would disrupt neuronal circuitry and may initiate apoptotic cell death, giving rise to the neurological disturbances manifested in clinical TSE cases. 相似文献
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Cellulose-based composites have attracted interest given the shift towards ‘green’ materials, but achieving uniform dispersions of cellulose in polymer matrices and/or enhancement of interfacial interactions between components remains challenging. Herein we report the preparation of polypyrrole/cellulose nanocomposites in [Cu(NH3)4(H2O)2](OH)2 (Schweizer''s reagent/cuoxam)-based reaction media via in situ polymerization. The effect of cellulose template morphology and reaction media on the microstructure, electrical conductivity, and surface wettability was studied. Aqueous reaction media favored the formation of a uniform polypyrrole coating encapsulating the cellulose fibers; concentrated cuoxam solutions promoted inhomogeneity and exhibited a progressive decline in conductivity. The maximum conductivity attained was 3.08 S cm−1 from a bacterial cellulose-templated composite prepared in aqueous reaction media and afforded an approximately threefold increase in conductivity when compared with pure PPy at 1.14 S cm−1. Generally, the composites resembled wetting surfaces – with highly concentrated cuoxam solutions yielding improved hydrophilicity, while substitution of bacterial cellulose with nanocrystalline cellulose engendered a shift towards hydrophobicity. Most composites displayed a contact angle of less than 90° suggesting PPy/cellulose composites tended towards hydrophilic behavior. This study highlights investigations into the viability of cellulose solvents as a facile means to control the structure and performance of in situ functionalized cellulose nanocomposites.The in situ polymerization of polypyrrole/cellulose nanocomposites using Schweizer''s reagent is demonstrated and measured against a number of structural, electrical, and colligative properties. 相似文献
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Ashlyn G. Rickard Meng Zhuang Christopher A. DeRosa Mark W. Dewhirst Cassandra L. Fraser Gregory M. Palmer 《Biomedical optics express》2022,13(7):3869
Intracellular oxygenation is an important parameter for numerous biological studies. While there are a variety of methods available for acquiring in vivo measurements of oxygenation in animal models, most are dependent on indirect oxygen measurements, restraints, or anesthetization. A portable microscope system using a Raspberry Pi computer and Pi Camera was developed for attaching to murine dorsal window chambers. Dual-emissive boron nanoparticles were used as an oxygen-sensing probe while mice were imaged in awake and anesthetized states. The portable microscope system avoids altered in vivo measurements due to anesthesia or restraints while enabling increased continual acquisition durations. 相似文献
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Dorothee Bienzle Joyce Rousseau David Marom Jennifer MacNicol Linda Jacobson Stephanie Sparling Natalie Prystajecky Erin Fraser J. Scott Weese 《Emerging infectious diseases》2022,28(6):1154
We tested swab specimens from pets in households in Ontario, Canada, with human COVID-19 cases by quantitative PCR for SARS-CoV-2 and surveyed pet owners for risk factors associated with infection and seropositivity. We tested serum samples for spike protein IgG and IgM in household pets and also in animals from shelters and low-cost neuter clinics. Among household pets, 2% (1/49) of swab specimens from dogs and 7.7% (5/65) from cats were PCR positive, but 41% of dog serum samples and 52% of cat serum samples were positive for SARS-CoV-2 IgG or IgM. The likelihood of SARS-CoV-2 seropositivity in pet samples was higher for cats but not dogs that slept on owners’ beds and for dogs and cats that contracted a new illness. Seropositivity in neuter-clinic samples was 16% (35/221); in shelter samples, 9.3% (7/75). Our findings indicate a high likelihood for pets in households of humans with COVID-19 to seroconvert and become ill. 相似文献
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A Jamieson GC Inglis M Campbell R Fraser JM Connell 《Archives of disease in childhood》1994,71(1):40-43
Glucocorticoid suppressible hyperaldosteronism (GSH) is an uncommon form of dominantly inherited hypertension. Presentation with hypertension and complications such as stroke in early life are well recognised. The use of a simple genetic test carried out on blood or placenta facilitates the detection of infants and children with GSH before the development of hypertension, allowing prompt treatment of hypertension if it occurs, and an opportunity to study the effects of growth and environmental influences on the progression of the condition. 相似文献
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Bradley S. Hollidge Mary-Virginia Salzano John M. Ibrahim Jonathan W. Fraser Valentina Wagner Nicole E. Leitner Susan R. Weiss Friedemann Weber Francisco Gonzlez-Scarano Samantha S. Soldan 《Viruses》2022,14(7)
La Crosse virus (LACV) is a major cause of pediatric encephalitis and aseptic meningitis in the Midwestern, Mid-Atlantic, and Southern United States, where it is an emerging pathogen. The LACV Gc glycoprotein plays a critical role in the neuropathogenesis of LACV encephalitis as the putative virus attachment protein. Previously, we identified and experimentally confirmed the location of the LACV fusion peptide within Gc and generated a panel of recombinant LACVs (rLACVs) containing mutations in the fusion peptide as well as the wild-type sequence. These rLACVs retained their ability to cause neuronal death in a primary embryonic rat neuronal culture system, despite decreased replication and fusion phenotypes. To test the role of the fusion peptide in vivo, we tested rLACVs in an age-dependent murine model of LACV encephalitis. When inoculated directly into the CNS of young adult mice (P28), the rLACV fusion peptide mutants were as neurovirulent as the rLACV engineered with a wild-type sequence, confirming the results obtained in tissue culture. In contrast, the fusion peptide mutant rLACVs were less neuroinvasive when suckling (P3) or weanling (P21) mice were inoculated peripherally, demonstrating that the LACV fusion peptide is a determinant of neuroinvasion, but not of neurovirulence. In a challenge experiment, we found that peripheral challenge of weanling (P21) mice with fusion peptide mutant rLACVs protected from a subsequent WT-LACV challenge, suggesting that mutations in the fusion peptide are an attractive target for generating live-attenuated virus vaccines. Importantly, the high degree of conservation of the fusion peptide amongst the Bunyavirales and, structurally, other arboviruses suggests that these findings are broadly applicable to viruses that use a class II fusion mechanism and cause neurologic disease. 相似文献