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91.
Following growth in a chemically defined medium (CDM), five strains of Streptococcus uberis were tested for their ability to survive killing by bovine neutrophils. Strains 0140J, ST10, EF20 and C221 were easily killed, whereas strain C197C was highly resistant. The ability of strain 0140J to resist phagocytosis and killing was increased by supplementation of the growth medium with milk whey, casaminoacids, casein, or, to a lesser extent, bovine serum. Supplementation of the growth medium with yeast extract or bovine serum albumin did not affect the resistance of this strain. Following growth in CDM supplemented with casein, strains ST10 and C221, like strain 0140J, were significantly more resistant to killing by neutrophils. The resistance of strains EF20 and C197C was unaffected by the addition of casein to the medium; strain EF20 remained susceptible and strain C197C highly resistant to killing. The effect of supplementing the growth media with components other than casein was only studied for strain 0140J. Decapsulation of strains C197C, ST10 and 0140J, grown in CDM + casein, with type-X hyaluronidase did not significantly affect their ability to survive in the presence of bovine neutrophils. 相似文献
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93.
Current theories hypothesize that dopamine neuronal firing encodes reward prediction errors. Although studies in nonhuman species provide direct support for this theory, functional magnetic resonance imaging (fMRI) studies in humans have focused on brain areas targeted by dopamine neurons [ventral striatum (VStr)] rather than on brainstem dopaminergic nuclei [ventral tegmental area (VTA) and substantia nigra]. We used fMRI tailored to directly image the brainstem. When primary rewards were used in an experiment, the VTA blood oxygen level-dependent (BOLD) response reflected a positive reward prediction error, whereas the VStr encoded positive and negative reward prediction errors. When monetary gains and losses were used, VTA BOLD responses reflected positive reward prediction errors modulated by the probability of winning. We detected no significant VTA BOLD response to nonrewarding events. 相似文献
94.
OBJECTIVE: To develop a set of microsatellite markers, composed of a minimal number of these markers, suitable for use in forensic genetic investigations in dogs. SAMPLE POPULATION: Blood, tissue, or buccal epithelial cells from 364 dogs of 85 breeds and mixed breeds and 19 animals from related species in the family Canidae. PROCEDURE: 61 tetranucleotide microsatellite markers were characterized on the basis of number and size of alleles, ease of genotyping, chromosomal location, and ability to be coamplified. The range in allele size, number of alleles, total heterozygosity, and fixation index for each marker were determined by use of genotype data from 383 dogs and related species. Polymorphism information content was calculated for several breeds of dogs. RESULTS: 7 microsatellite markers could be coamplified. These markers were labeled with fluorescent dyes, multiplexed into a single reaction, and optimized for resolution in a commercial genetic analyzer. The multiplex set was used to identify sires for 2 mixed litters. The test was not species specific; genotype information collected for wolves, coyotes, jackals, New Guinea singing dogs, and an African wild dog could not distinguish between these species. CONCLUSIONS AND CLINICAL RELEVANCE: This set of 7 microsatellite markers is useful in forensic applications (ie, identification of dogs and determination of parentage) in closely related animals and is applicable to a wide range of species belonging to the family Canidae. 相似文献
95.
OBJECTIVE: To compare the sensory and motor effects of adding medetomidine to mepivicaine, administered either perineurally or systemically, for radial nerve block in dogs. STUDY DESIGN: Prospective randomized cross-over study. ANIMALS: Six healthy Beagles, aged 18.7 +/- 6.3 months and weighing 10.4 +/- 1.3 kg. METHODS: Dogs were anesthetized briefly with sevoflurane on three separate occasions and received each treatment administered in random order: mepivacaine 5 mg kg(-1) perineurally around the radial nerve with saline 0.01 mL kg(-1) intramuscularly (CONTROL); mepivacaine 5 mg kg(-1) and medetomidine 0.01 mg kg(-1) combined, perineurally with saline 0.01 mL kg(-1) intramuscularly (MEDPN); mepivacaine 5 mg kg(-1) perineurally around the radial nerve with medetomidine 0.01 mg kg(-1) intramuscularly (MEDIM). All nerve blocks were performed with the aid of a nerve locator. Motor effects were evaluated based on the ability to bear weight. Sensory effects were evaluated by the response to a graded-electrical stimulus. These were evaluated at 5-minute intervals for the first hour, and at 10-minute intervals thereafter. Mean intervals were calculated as follows: time to motor block onset, duration of motor block, time to peak sensory block, duration of peak sensory block (i.e. period of no response to maximal stimulus intensity), and duration of residual sensory block (i.e. time to return to baseline sensory function). Treatment means were compared using a one-way analysis of variance for repeated measures and, where significant differences were noted, a Student-Newman-Keuls test was applied; p < 0.05 was considered significant. RESULTS: Medetomidine, administered either systemically or perineurally, significantly prolonged duration of peak motor block, peak sensory block, and residual sensory block compared with CONTROL. CONCLUSION: Medetomidine prolonged sensory and motor blockade after radial nerve block with mepivacaine in dogs. CLINICAL RELEVANCE: Medetomidine may prove to be a useful adjunct to peripheral nerve blockade with local anesthetics. 相似文献
96.
Antimicrobial resistance of fecal Escherichia coli isolated from grow-finish pigs in 20 herds in Alberta and Saskatchewan.
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Leigh B. Rosengren Cheryl L. Waldner Richard J. Reid-Smith Sylvia L. Checkley Margaret E. McFall Andrijana Raji? 《Canadian journal of veterinary research》2008,72(2):160-167
Escherichia coli (n = 1439), isolated from the feces of apparently healthy grow-finish pigs in 20 herds in Alberta and Saskatchewan, were tested for susceptibility to 16 antimicrobials. All isolates were susceptible to amikacin, ceftriaxone, and ciprofloxacin and less than 1% was resistant to amoxicillin-clavulanic acid, cefoxitin, ceftiofur, gentamicin, and nalidixic acid. Resistance was most common to tetracycline (66.8%), sulfamethoxazole (46.0%) and streptomycin (33.4%). Twenty-one percent of the isolates were susceptible to all drugs, while 57% were resistant to 2 or more antimicrobials. Unconditional associations between resistances provided insight into the potential for co-selection. Every resistance-outcome was associated with at least 2 other drug-resistances. These associations illustrate the propensity for resistance phenotypes to occur together and the importance of considering co-selection in antimicrobial use decisions. A 2nd analysis explored the associations between resistance phenotypes in E. coli and Salmonella spp. from the same herd. Only 2 resistances in Salmonella were associated with herd-level E. coli resistance, indicating that E. coli is a poor sentinel for Salmonella AMR within herds. Herd-level management, including antimicrobial use, could affect antimicrobial resistance. The intra-class correlation between isolates within herds ranged from 0.1 to 0.46, which confirmed resistance clustered within herds. This suggests herd-level interventions might mitigate antimicrobial resistance. Overall, these results reflect the on-farm selection pressure for resistance and the potential food-safety risk from near-market animals. These data provide a baseline for comparisons with future on-farm monitoring of antimicrobial resistance in E. coli. 相似文献
97.
Cheryl L. Waldner Richard I. Kennedy Leigh Rosengren Edward G. Clark 《The Canadian veterinary journal. La revue veterinaire canadienne》2009,50(5):491-499
The objectives were to describe the pattern of losses through culling, sales of breeding stock, mortality, and disappearance, and to characterize the causes of mortality of cows and replacement heifers of breeding age from Western Canadian beef herds. Cows and replacement heifers from 203 herds were observed for a 1-year period starting June 1, 2001. Veterinarians examined dead animals on-farm using a standard postmortem protocol. The incidence of culling in cows and replacements heifers was 14.3 per 100 cow-years at risk, and the frequencies of sales for breeding stock, mortality, and cows reported missing per cow-years at risk were 4.0, 1.1, and 0.4, respectively. During the study, 355 animals died or were euthanized, 209 were examined postmortem, and the requested tissues were submitted for histopathologic examination from 184. A cause of death was determined for 70% (128/184) of the cows with complete gross postmortem and histopathologic examinations. Hardware disease (traumatic reticuloperitonitis), malignant neoplasia (cancer), calving-associated injury, rumen tympany (bloat), myopathy, and pneumonia accounted for 56% (72/128) of the animals where a cause of death was determined. Twenty-three other causes of death accounted for the remaining 44% (56/128). Factors relating to cow nutrition accounted for 25% of the deaths, emphasizing the importance of feeding management as a determinant of cow health in western Canada. 相似文献
98.
99.
Isolation and characterization of polyphenol type-A polymers from cinnamon with insulin-like biological activity 总被引:10,自引:0,他引:10
Anderson RA Broadhurst CL Polansky MM Schmidt WF Khan A Flanagan VP Schoene NW Graves DJ 《Journal of agricultural and food chemistry》2004,52(1):65-70
The causes and control of type 2 diabetes mellitus are not clear, but there is strong evidence that dietary factors are involved in its regulation and prevention. We have shown that extracts from cinnamon enhance the activity of insulin. The objective of this study was to isolate and characterize insulin-enhancing complexes from cinnamon that may be involved in the alleviation or possible prevention and control of glucose intolerance and diabetes. Water-soluble polyphenol polymers from cinnamon that increase insulin-dependent in vitro glucose metabolism roughly 20-fold and display antioxidant activity were isolated and characterized by nuclear magnetic resonance and mass spectroscopy. The polymers were composed of monomeric units with a molecular mass of 288. Two trimers with a molecular mass of 864 and a tetramer with a mass of 1152 were isolated. Their protonated molecular masses indicated that they are A type doubly linked procyanidin oligomers of the catechins and/or epicatechins. These polyphenolic polymers found in cinnamon may function as antioxidants, potentiate insulin action, and may be beneficial in the control of glucose intolerance and diabetes. 相似文献
100.
Broadhurst CL Schmidt WF Crawford MA Wang Y Li R 《Journal of agricultural and food chemistry》2004,52(13):4250-4255
In the (13)C NMR spectra of natural, unenriched docosahexaenoic acid-rich sardine oil and cod muscle glycerophosphocholine significant signal intensity differences across the 1D spectrum between undiluted and diluted samples were observed. In undiluted samples (13)C-(13)C 2D nuclear Overhauser enhancement spectroscopy (NOESY) interchain cross-peaks for CH, CH(2), CH(3), and C=C structures were observed. Results indicate that in undiluted natural lipids, NMR signal intensity is influenced by polarization transfer from the extended lipid structure. The NOE enhancement of specific molecular sites especially in unsaturated lipids is evidence that some natural lipids remain oriented relative to each other and in an orderly arrangement at the molecular level long enough for the effect to be detected by the NMR experiment. The presence of polyunsaturated fatty acids in mixtures of natural lipids could stabilize specific local molecular conformations within the remaining less saturated lipids. 相似文献