Identification and antibiotic susceptibility of bacterial isolates from dogs with otitis externa in Australia     

DL Bugden 《Australian veterinary journal》2013,91(1-2):43-46

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Oral vaccination of brushtail possums with BCG: Investigation into factors that may influence vaccine efficacy and determination of duration of protection     

BM Buddle  FE Aldwell  DL Keen  NA Parlane  KL Hamel  GW de Lisle 《New Zealand veterinary journal》2013,61(5):224-230

AIMS: To determine factors that may influence the efficacy of an oral pelleted vaccine containing Mycobacterium bovis bacille Calmette-Guérin (BCG) to induce protection of brushtail possums against tuberculosis. To determine the duration of protective immunity following oral administration of BCG.

METHODS: In Study 1, a group of possums (n=7) was immunised by feeding 10 pellets containing dead Pasteur BCG, followed 15 weeks later with a single pellet of live Pasteur BCG. At that time, four other groups of possums (n=7 per group) were given a single pellet of live Pasteur BCG orally, a single pellet of live Danish BCG orally, 10 pellets of live Pasteur BCG orally, or a subcutaneous injection of live Pasteur BCG. For the oral pelleted vaccines, BCG was formulated into a lipid matrix, and each pellet contained approximately 10⁷ colony forming units (cfu) of BCG, while the vaccine injected subcutaneously contained 10⁶ cfu of BCG. A sixth, non-vaccinated, group (n=7) served as a control. All possums were challenged by the aerosol route with a low dose of virulent M. bovis 7 weeks after vaccination, and killed 7–8 weeks after challenge. Protection against challenge with M. bovis was assessed from pathological and bacteriological findings.

In Study 2, lipid-formulated live Danish BCG was administered orally to three groups of possums (10–11 per group), and these possums were challenged with virulent M. bovis 8, 29 or 54 weeks later. The possums were killed 7 weeks after challenge, to assess protection in comparison to a non-vaccinated group.

RESULTS: The results from Study 1 showed that vaccine efficacy was not adversely affected by feeding dead BCG prior to live BCG. Feeding 10 vaccine pellets induced a level of protection similar to feeding a single pellet. Protection was similar when feeding possums a single pellet containing the Pasteur or Danish strains of BCG. All vaccinated groups had significantly reduced pathological changes or bacterial counts when compared to the non-vaccinated group. In Study 2, oral administration of Danish BCG induced protection against challenge with M. bovis, which persisted for at least 54 weeks after vaccination. Some protection was observed in possums challenged 54 weeks after vaccination, but this protection was significantly less than that observed in groups vaccinated 29 or 8 weeks prior to challenge. There was a strong relationship between the proportion of animals producing positive lymphocyte proliferation responses to M. bovis antigens and protection against challenge with M. bovis.

CONCLUSIONS: Factors considered potentially capable of interfering with vaccination, including feeding dead BCG to possums prior to feeding live BCG, feeding multiple doses of BCG at one time, and changing strains of BCG, were shown not to interfere with the acquisition of protective immune responses in possums. Protection against tuberculosis was undiminished up to 29 weeks after vaccination with BCG administered orally. It is concluded that vaccination of possums by feeding pellets containing BCG is a robust and efficient approach to enhance the resistance of these animals to tuberculosis.  相似文献   

Epidemiology and conservation implications of Trichomonas gallinae infection in the endangered Mauritian pink pigeon     

N. Bunbury  C.G. Jones  A.G. Greenwood 《Biological conservation》2008,141(1):153-161

Despite increasing recognition of the role of exotic pathogens in species decline, comprehensive studies of wildlife disease epidemiology in threatened species are rare. We investigated the epidemiology of the protozoan parasite Trichomonas gallinae, which causes the avian disease trichomonosis, in the five wild subpopulations of the endangered pink pigeon Columba mayeri in Mauritius. An average of 89% of the entire population was screened for T. gallinae infection every 2 months between September 2002 and April 2004. A total of 426 individual pink pigeons (all >3 months of age) was screened, and 359 (84.3%) of these tested positive for T. gallinae at least once. Average prevalence of T. gallinae infection across all subpopulations and sampling periods was 50.3% but ranged from 19.6% to 82.4%. Trichomonas gallinae infection was significantly different among subpopulations and prevalence gradually decreased over the entire screening period. Infection prevalence also increased with host age. Observed pathogenicity of T. gallinae was low; active trichomonosis signs were recorded in ca. 1.9% of birds which tested positive. However, birds which persistently tested positive for T. gallinae (33.5% of birds screened) were at least 10% less likely to survive 2 yrs post-screening than birds which tested negative at least once in three consecutive periods; a finding which should be considered by wildlife disease investigators if no pathogenic effects are apparent from the results of studies based on a single screening episode. We conclude that T. gallinae is an additional population limiting factor for pink pigeons and our study highlights the importance of screening other endangered columbids for this pathogen.  相似文献   

IL‐31‐induced pruritus in dogs: a novel experimental model to evaluate anti‐pruritic effects of canine therapeutics          下载免费PDF全文

Andrea J. Gonzales  Timothy J. Fleck  William R. Humphrey  Betsy A. Galvan  Michelle M. Aleo  Sean P. Mahabir  Jezaniah‐Kira Tena  Karen G. Greenwood  Robert B. McCall 《Veterinary dermatology》2016,27(1):34-e10

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Photoemission evidence for a remnant fermi surface and a d-wave-like dispersion in insulating Ca2CuO2Cl2     

F Ronning  C Kim  DL Feng  DS Marshall  AG Loeser  LL Miller  JN Eckstein  I Bozovic  Z Shen 《Science (New York, N.Y.)》1998,282(5396):2067-2072

An angle-resolved photoemission study is reported on Ca2CuO2Cl2, a parent compound of high-Tc superconductors. Analysis of the electron occupation probability, n(k), from the spectra shows a steep drop in spectral intensity across a contour that is close to the Fermi surface predicted by the band calculation. This analysis reveals a Fermi surface remnant, even though Ca2CuO2Cl2 is a Mott insulator. The lowest energy peak exhibits a dispersion with approximately the &cjs3539;coskxa - coskya&cjs3539; form along this remnant Fermi surface. Together with the data from Dy-doped Bi2Sr2CaCu2O8+delta, these results suggest that this d-wave-like dispersion of the insulator is the underlying reason for the pseudo gap in the underdoped regime.  相似文献   

In search of the first flower: A jurassic angiosperm, archaefructus, from northeast china   总被引：1，自引：0，他引：1  

G Sun  DL Dilcher  S Zheng  Z Zhou 《Science (New York, N.Y.)》1998,282(5394):1692-1695

Angiosperm fruiting axes were discovered from the Upper Jurassic of China. Angiosperms are defined by carpels enclosing ovules, a character demonstrated in this fossil. This feature is lacking in other fossils reported to be earliest angiosperms. The fruits are small follicles formed from conduplicate carpels helically arranged. Adaxial elongate stigmatic crests are conspicuous on each carpel. The basal one-third of the axes bore deciduous organs of uncertain affinities. No scars of subtending floral organs are present to define the individual fertile parts as floral units, but the leaf-like structures subtending each axis define them as flowers. These fruiting axes have primitive characters and characters not considered primitive.  相似文献   

Forest fires: An example of self-organized critical behavior   总被引：1，自引：0，他引：1  

BD Malamud  G Morein  DL Turcotte 《Science (New York, N.Y.)》1998,281(5384):1840-1842

Despite the many complexities concerning their initiation and propagation, forest fires exhibit power-law frequency-area statistics over many orders of magnitude. A simple forest fire model, which is an example of self-organized criticality, exhibits similar behavior. One practical implication of this result is that the frequency-area distribution of small and medium fires can be used to quantify the risk of large fires, as is routinely done for earthquakes.  相似文献   

Compensation of horizontal temperature and salinity gradients in the ocean mixed layer   总被引：1，自引：0，他引：1  

DL Rudnick  R Ferrari 《Science (New York, N.Y.)》1999,283(5401):526-529

Establishment of the temperature-salinity relationship in the ocean has concerned oceanographers for decades because of its importance for understanding ocean circulation. High-resolution measurements in the ocean mixed layer are used to show that temperature and salinity gradients on horizontal scales of 20 meters to 10 kilometers tend to compensate in their effect on density. These observations support the notion of a horizontal mixing in the mixed layer that depends on density gradient.  相似文献   

Temperament and hypothalamic-pituitary-adrenal axis function are related and combine to affect growth, efficiency, carcass, and meat quality traits in Brahman steers     

Cafe LM  Robinson DL  Ferguson DM  Geesink GH  Greenwood PL 《Domestic animal endocrinology》2011,40(4):230-240

Associations between temperament, stress physiology, and productivity were studied in yearling Brahman steers (n = 81). Steers differed in calpain system gene marker status; 41 were implanted with a hormonal growth promotant at feedlot entry. Temperament was assessed with repeated measurements of flight speed (FS) and crush score (CS) during 6 mo of backgrounding at pasture and 117 d of grain finishing. Adrenal responsiveness was assessed with ACTH challenge, with plasma samples collected immediately before and 60 min after challenge. Steers with higher FS and CS had higher prechallenge plasma cortisol, glucose, lactate, and nonesterified fatty acid concentrations. The ACTH-induced cortisol response was unrelated to FS or CS, but glucose remained higher after challenge in flightier steers. The hormonal growth promotant reduced adrenal responsiveness; tenderness genotype had no effect. When temperament assessments and cortisol concentrations before and after challenge were combined in a principal components analysis, four vectors accounting for 38%, 25%, 18%, and 9% of the variation were identified. The first vector had significant loadings on temperament and prechallenge cortisol; increasing scores were associated with increased plasma glucose, lactate, and nonesterified fatty acid and with reductions in BW and feedlot growth rates, carcass fatness, and muscle pH. The second vector loaded only on ACTH-induced cortisol response; increased scores related to increased residual feed intake, number of daily feed sessions, and meat marbling score. The third and fourth vectors had different loadings on FS and CS and appeared to identify different aspects of temperament measured by FS or CS. Fewer associations were found between the third or fourth vectors and productivity traits, possibly because of lower variance accounted for by these vectors. In conclusion, temperament was related to prechallenge cortisol but not to ACTH-induced cortisol response. Principal components analysis separated these traits into separate components, which in turn had different relations with productivity traits. The largest component of temperament was described similarly by FS and CS, but there were smaller components that these described differently. There were some temperament-related differences in the metabolic status of the steers which were not related to the variation in cortisol, suggesting involvement of the sympatho-adrenal-medullary axis in these temperament-related effects.  相似文献   

The relationship between the Physicochemical properties of pyrethroid insecticides and their speed of neurotoxic action     

Martyn G. Ford  Richard Greenwood  Lucy D. Leake  Richard M. Szydlo  Christopher H. Turner 《Pest management science》1985,16(6):673-683

The rate of onset of pyrethroid-induced depolarisations of the nerve cell membrane in isolated ganglia of the leech Hirudo medicinalis was measured using intracellular recordings. The speed of neurotoxicity of a series of substituted benzyl (1RS)-trans-cyclopropane-1-carboxylates was related to the size of the groups at C3 and C4 of the benzyl ring, the ability of the ring substituents to donate electrons, and the nature of the substituents at the two terminal positions of the vinyl group subtended by the cyclopropane ring. The speed of action was also related to the electronic environment of the protons subtended by the geminal methyl group held trans to the carboxyl group. Compounds, the partition properties of which were sensitive to interactions between the pyrethroid and solvent molecules, tended to act rapidly. There was no simple relationship between the speed of neurotoxic action in isolated leech ganglia and the knockdown potency to mustard beetles.  相似文献