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1.
D G Powell 《Veterinary Clinics of North America: Equine Practice》1991,7(1):27-52
The diagnosis of any viral respiratory disease relies on laboratory procedures to isolate the virus and demonstrate a significant rise in serum antibody titers. To isolate viruses from the upper respiratory tract, it is imperative that nasopharyngeal swabs are obtained from animals in the early acute stage of illness, i.e., during the pyrexic phase when the virus is replicating. Nasopharyngeal swabs must be placed in a virus transport medium and forwarded immediately to the laboratory at refrigerated temperature. Equine influenza, rhinopneumonitis, and equine viral arteritis are the three viral infections causing outbreaks of respiratory disease in North America. African horse sickness, although foreign to North America, could be introduced despite stringent horse importation regulations. Specific antiviral therapy is not available to treat viral respiratory disease in the horse. A variety of inactivated and modified live vaccines, however, are available to prevent clinical disease and the spread of infection caused by the common viral respiratory pathogens. A considerable amount of research is underway to enhance the potency and duration of immunity of the present vaccines against influenza and rhinopneumonitis. This research is directed at defining and characterizing the importance of specific glycoprotein antigens on the surface of the virus, which trigger the various host immune responses, and determining whether they are stimulatory or suppressive. 相似文献
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Low HC Powell CC Veir JK Hawley JR Lappin MR 《American journal of veterinary research》2007,68(6):643-648
OBJECTIVE: To use PCR assays to determine the prevalence of feline herpesvirus 1 (FHV-1), Chlamydophila felis, and Mycoplasma spp DNA in conjunctival cells collected from cats with and without conjunctivitis; to compare results of conventional and real-time fluorogenic PCR assays for amplification of FHV-1 DNA; and to determine whether copy numbers of FHV-1 DNA are correlated with conjunctivitis. ANIMALS: 55 cats with active conjunctivitis, 39 healthy cats that never had conjunctivitis, and 32 cats with a history of conjunctivitis that had been resolved for at least 3 months. PROCEDURES: Samples were obtained by rolling cotton-tipped applicators on the ventral conjunctiva of awake cats treated topically with proparacaine. The DNA was extracted from the swab specimens and assessed in PCR assays to detect DNA of FHV-1 (fluorogenic PCR assay and conventional PCR assay), Mycoplasma spp (conventional PCR assay), and C felis (conventional PCR assay). RESULTS: Overall prevalence rates of FHV-1, C felis, and Mycoplasma spp as assessed by the conventional PCR assays were 6.7%, 3.2%, and 9.6%, respectively. Percentage concordance between conventional PCR and fluorogenic PCR assays for FHV-1 was 92.5%. There were no significant differences among the 3 groups of cats for the mean copy number of FHV-1 divided by the copy number of glyceraldehyde-3-phosphate dehydrogenase. CONCLUSIONS AND CLINICAL RELEVANCE: Mycoplasma spp were the most prevalent organism detected and was associated with conjunctivitis. This study could not confirm that there are increased copy numbers of FHV-1 DNA in cats with conjunctivitis, compared with the copy numbers for cats without conjunctivitis. 相似文献
4.
Jeff R. Powell Rachel G. Campbell Kari E. Dunfield Robert H. Gulden Miranda M. Hart David J. Levy-Booth John N. Klironomos K. Peter Pauls Clarence J. Swanton Jack T. Trevors Pedro M. Antunes 《Applied soil ecology》2009,41(1):128-136
Most soybeans grown in North America are genetically modified (GM) to tolerate applications of the broad-spectrum herbicide glyphosate; as a result, glyphosate is now extensively used in soybean cropping systems. Soybean roots form both arbuscular mycorrhizal (AM) and rhizobial symbioses. In addition to individually improving host plant fitness, these symbioses also interact to influence the functioning of each symbiosis, thereby establishing a tripartite symbiosis. The objectives of this study were to (1) estimate the effects of glyphosate on the establishment and functioning of AM and rhizobial symbioses with GM soybean, and (2) to estimate the interdependence of the symbioses in determining the response of each symbiosis to glyphosate. These objectives were addressed in two experiments; the first investigated the importance of the timing of glyphosate application in determining the responses of the symbionts and the second varied the rate of glyphosate application. Glyphosate applied at recommended field rates had no effect on Glomus intraradices or Bradyrhizobium japonicum colonization of soybean roots, or on soybean foliar tissue [P]. N2-fixation was greater for glyphosate-treated soybean plants than for untreated-plants in both experiments, but only when glyphosate was applied at the first trifoliate soybean growth stage. These data deviate from previous studies estimating the effect of glyphosate on the rhizobial symbiosis, some of which observed negative effects on rhizobial colonization and/or N2-fixation. We did observe evidence of the response of one symbiont (stimulation of N2-fixation following glyphosate) being dependent on co-inoculation with the other; however, this interactive response appeared to be contextually dependent as it was not consistent between experiments. Future research needs to consider the role of environmental factors and other biota when evaluating rhizobial responses to herbicide applications. 相似文献
5.
Allyson C. Berent DVM Jeffrey Todd DVM Jennifer Sergeeff DVM DACVIM Lisa L. Powell DVM DACVECC 《Journal of Veterinary Emergency and Critical Care》2005,15(2):128-135
Objective: To describe diagnostics, therapy, and sequelae of acute carbon monoxide (CO) toxicity because of a motor vehicle generator in 4 dogs and 2 cats. Series summary: Four dogs and 2 cats presented for recumbency, disorientation, dyspnea, and stiffness after an estimated 6–8 hour exposure to exhaust from a generator. Diagnostics included a serum carboxyhemoglobin levels evaluation, arterial blood gas analysis, pulse oximetry readings, and blood pressure measurements. Initial therapy included oxygen (O2) administration, intravenous bronchodilators, fluids, and a hemoglobin‐based O2 carrying (HBOC) molecule. Following administration of the HBOC, 4 of the 6 animals showed dramatic clinical improvement. Two weeks after hospital discharge, the owner reported potential hearing deficits in all animals. Brain auditory evoked response (BAER) tests were conducted in all surviving animals and some degree of hearing impairment was documented in all cases, with complete clinical resolution noted 6 weeks later. Unique information provided: This report describes the therapeutic use of an HBOC in acute isolated CO toxicity (i.e. without the complications of smoke inhalation). In addition, delayed nervous system dysfunction was documented in all surviving animals. 相似文献
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8.
Sporotrichosis in a dog 总被引:2,自引:0,他引:2
G Koehne H S Powell R I Hail 《Journal of the American Veterinary Medical Association》1971,159(7):892-894
9.
L.N Payne P.C Powell M.C Rennie L.J.N Ross 《Comparative immunology, microbiology and infectious diseases》1978,1(1-2):31-36
Current knowledge of the nature of the antigens and of the host immune responses in vaccinal immunity to Marek's disease is reviewed. It is suggested that a two-step mechanism of resistance operates. The first step involves humoral and cell-mediated responses directed against viral antigens; the second step occurs after challenge with Marek's disease virus and consists of cellmediated responses directed against tumour cells. 相似文献
10.
Cloning,expression, purification,and biological activity of five feline type I interferons 总被引:1,自引:0,他引:1
Wonderling R Powell T Baldwin S Morales T Snyder S Keiser K Hunter S Best E McDermott MJ Milhausen M 《Veterinary immunology and immunopathology》2002,89(1-2):13-27
Type I interferons (IFN) are important mediators of the host defense against viral infections in mammals. In humans multiple subtypes of IFN-alpha exist, most of which possess antiviral activity. Little is known about the type I IFN genes in cats and the role they may play in feline immunological responses to viruses. We have isolated cDNAs encoding five feline IFN-alpha (feIFN) subtypes that share from 95 to 99% amino acid sequence identity. FeIFN-alpha5 has five additional amino acids inserted at position 139, which are not present in the other four subtypes. Sequence identity of the feIFN proteins encoded by the five clones compared to human IFN-alpha2 is approximately 60%. Unlike most of the human subtypes, each of the five feline IFN sequences has an N-glycosylation recognition site. Expression of all five feIFN-alpha subtypes in Chinese hamster ovary (CHO) cells was confirmed by Western blot analysis, and all resulting proteins were glycosylated. The antiviral activity of each feIFN-alpha subtype produced in transiently transfected CHO cell cultures was tested in vitro. In addition, subtype feIFN-alpha6 was expressed in the yeast, Pichia pastoris. The resulting secreted mature recombinant protein was purified and demonstrated significant antiviral activity and induction of 2',5'-oligoadenylate synthetase activity in vitro. 相似文献