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81.
Meyer-Luehmann M Coomaraswamy J Bolmont T Kaeser S Schaefer C Kilger E Neuenschwander A Abramowski D Frey P Jaton AL Vigouret JM Paganetti P Walsh DM Mathews PM Ghiso J Staufenbiel M Walker LC Jucker M 《Science (New York, N.Y.)》2006,313(5794):1781-1784
Protein aggregation is an established pathogenic mechanism in Alzheimer's disease, but little is known about the initiation of this process in vivo. Intracerebral injection of dilute, amyloid-beta (Abeta)-containing brain extracts from humans with Alzheimer's disease or beta-amyloid precursor protein (APP) transgenic mice induced cerebral beta-amyloidosis and associated pathology in APP transgenic mice in a time- and concentration-dependent manner. The seeding activity of brain extracts was reduced or abolished by Abeta immunodepletion, protein denaturation, or by Abeta immunization of the host. The phenotype of the exogenously induced amyloidosis depended on both the host and the source of the agent, suggesting the existence of polymorphic Abeta strains with varying biological activities reminiscent of prion strains. 相似文献
82.
Merchant ME Leger N Jerkins E Mills K Pallansch MB Paulman RL Ptak RG 《Veterinary immunology and immunopathology》2006,110(3-4):221-228
Leukocytes were isolated from whole blood of wild alligators by differential sedimentation. The leukocytes were disrupted in 5% AcOH and the crude extracts processed by ultrafiltration. The extracts were subjected to solvent exchange (0.1% AcOH) and the fraction that contained macromolecules between 1 and 10 kDa were subjected to further analyses. The acid extracts of the alligator leukocytes exhibited substantial antimycotic activities against six of eight species of Candida yeast tested. In addition, the alligator leukocyte extracts were effective as antimicrobial agents against 10 of 12 bacterial species, and displayed moderate activity against two enveloped viruses (human immunodeficiency virus-1 and herpes simplex virus-1HF). Kinetic analyses revealed that the antimycotic effects of the leukocyte extract occurred rapidly, with 64% fungal growth inhibition within 3 min of exposure. The molecule(s) responsible for the antimicrobial activities were sensitive to proteases, heat-stable, acid soluble, and in the 1–10 kDa range. These data suggest that alligator leukocytes express cationic peptides that are responsible for their antimicrobial properties. 相似文献
83.
Melanie Caffe‐Treml Karl D. Glover Padmanaban G. Krishnan Gary A. Hareland 《Cereal Chemistry》2010,87(6):574-580
Because of the large number of cultivars that require examination in the development of spring wheat (Triticum aestivum L.) cultivars, breeding programs use predictive methods to test end use quality. The Mixograph is a widely used predictive test with which end use quality of many genotypes can be assessed in a short time. By comparison, the Mixolab is a relatively new device with additional capability that might be used for the same purpose. Our objective was to document variability of, and relationships among, 20 parameters obtained from Mixolab, Mixograph, and bake tests. Tests were performed on flour from 18 genotypes grown in 20 environments. Both genotype and environment had significant effects on quality parameter values. Several Mixograph and Mixolab parameters were highly significantly correlated, particularly when genotype mean values over environments were considered. Correlations between loaf volume and Mixolab parameters within environments were inconsistent and suggest that average genotype values over environments will be most useful. For example, the correlation between Mixolab stability and loaf volume (r = 0.25, P < 0.001) was much higher when genotype averages (r = 0.70, P < 0.001) were considered. Our results show that selection for Mixolab stability and water absorption should help delineate and improve the selection of genotypes with greater loaf volume. 相似文献
84.
Charles F. Adams Elizabeth N. Brooks Christopher M. Legault Melanie A. Barrett David F. Chevrier 《Fisheries Management and Ecology》2021,28(5):417-427
Allocating quotas among stakeholders requires an agreed-upon formula. If the stock unit spans multiple management jurisdictions, the formula may require updated biomass estimates of the stock's spatial distribution with respect to those jurisdictions. Data for calculating stock biomass often come from fishery-independent surveys. While stratified random sampling is a common design, strata boundaries may not always align with state or national jurisdictions, requiring post hoc stratification and imputation to calculate area-specific biomass. The vector autoregressive spatiotemporal (VAST) model was explored as a tool for calculating fish biomass within subareas of a defined stock unit for three different stocks jointly managed by the United States and Canada on Georges Bank in the Northwest Atlantic Ocean. VAST estimated proportions of stock biomass in each nation's waters were compared with an existing allocation algorithm that utilises a loess smooth through the average design-based swept area biomass from three fishery-independent surveys. The ability of VAST to impute biomass when no tows occur in a subarea of a survey stratum was demonstrated, as well as the relatively smoother biomass trend compared with design-based estimates, which may be desirable if the intent is to avoid large inter-annual swings in allocated quota. 相似文献
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87.
OBJECTIVES: To compare the precision obtained with computer-assisted screw insertion for treatment of mid-sagittal articular fractures of the distal phalanx (P3) with results achieved with a conventional technique. STUDY DESIGN: In vitro experimental study. SAMPLE POPULATION: Thirty-two cadaveric equine limbs. METHODS: Four groups of 8 limbs were studied. Either 1 or 2 screws were inserted perpendicular to an imaginary axial fracture of P3 using computer-assisted surgery (CAS) or conventional technique. Screw insertion time, predetermined screw length, inserted screw length, fit of the screw, and errors in placement were recorded. RESULTS: CAS technique took 15-20 minutes longer but resulted in greater precision of screw length and placement compared with the conventional technique. CONCLUSION: Improved precision in screw insertion with CAS makes insertion of 2 screws possible for repair of mid-sagittal P3 fractures. CLINICAL RELEVANCE: CAS although expensive improves precision in screw insertion into P3 and consequently should yield improved clinical outcome. 相似文献
88.
Cholangiohepatitis and pancreatitis secondary to severe gastroduodenal ulceration in a foal
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Buote M 《The Canadian veterinary journal. La revue veterinaire canadienne》2003,44(9):746-748
A 2-month-old foal was presented with clinical signs of colic. Gastroduodenal ulceration was suspected. A poor response to medical treatment and signs of gastroduodenal obstruction led to celiotomy and an attempted bypass procedure. The foal was euthanized and postmortem examination revealed gastric ulceration, segmental duodenal stenosis, and severe chronic cholangiohepatitis and pancreatitis. 相似文献
89.
Amir N Hamir Janice M Miller Randall C Cutlip Robert A Kunkle Allen L Jenny Mick J Stack Melanie J Chaplin Juergen A Richt 《Journal of veterinary diagnostic investigation》2004,16(4):316-321
This is a final report of an experimental transmission of sheep scrapie agent by intracerebral inoculation to Rocky Mountain elk (Cervus elaphus nelsoni). It documents results obtained in experimental (n = 6) and control (n = 2) elk. During the first 2 years postinoculation (PI), 3 animals died or were euthanized because of infection or injuries other than spongiform encephalopathy (SE). In years 3 and 4 PI, 3 other inoculated elk died after brief terminal neurological episodes. Necropsy of these animals revealed moderate weight loss but no other gross lesions. Microscopically, characteristic lesions of SE were seen throughout the brain and spinal cord, and the tissue was positive for proteinase K-resistant prion protein (PrPres) by immunohistochemistry (IHC) and by Western blot. Scrapie-associated fibrils (SAF) were observed by negative-stain electron microscopy in the brain of elk with neurologic signs. PrPres and SAF were not detected in the 3 inoculated elk necropsied during the first 2 years or in the 2 control animals. Retrospective analysis of the gene-encoding cervid PrP revealed a polymorphism at codon 132. The elk with SE were either homozygous (MM) or heterozygous (LM). These findings confirm that intracerebral inoculation of sheep scrapie agent results in SE with accumulations of PrPres in the central nervous system of elk. Based on morphologic and IHC findings, the experimentally induced SE cannot be distinguished from chronic wasting disease of elk with currently available diagnostic techniques. 相似文献
90.
Amir N Hamir Robert A Kunkle Randall C Cutlip Janice M Miller Katherine I O'Rourke Elizabeth S Williams Michael W Miller Mick J Stack Melanie J Chaplin Jürgen A Richt 《Journal of veterinary diagnostic investigation》2005,17(3):276-281
This communication reports final observations on experimental transmission of chronic wasting disease (CWD) from mule deer to cattle by the intracerebral route. Thirteen calves were inoculated intracerebrally with brain suspension from mule deer naturally affected with CWD. Three other calves were kept as uninoculated controls. The experiment was terminated 6 years after inoculation. During that time, abnormal prion protein (PrP(res)) was demonstrated in the central nervous system (CNS) of 5 cattle by both immunohistochemistry and Western blot. However, microscopic lesions suggestive of spongiform encephalopathy (SE) in the brains of these PrP(res)-positive animals were subtle in 3 cases and absent in 2 cases. Analysis of the gene encoding bovine PRNP revealed homozygosity for alleles encoding 6 octapeptide repeats, serine (S) at codon 46, and S at codon 146 in all samples. Findings of this study show that although PrP(res) amplification occurred after direct inoculation into the brain, none of the affected animals had classic histopathologic lesions of SE. Furthermore, only 38% of the inoculated cattle demonstrated amplification of PrP(res). Although intracerebral inoculation is an unnatural route of exposure, this experiment shows that CWD transmission in cattle could have long incubation periods (up to 5 years). This finding suggests that oral exposure of cattle to CWD agent, a more natural potential route of exposure, would require not only a much larger dose of inoculum but also may not result in amplification of PrP(res) within CNS tissues during the normal lifespan of cattle. 相似文献