Acute laminitis has been associated with the release of compounds, as yet unidentified, produced by hindgut fermentation which affect blood flow to the digit. The objectives of this study were to identify amine compounds in equine caecal and colonic contents, some of which are known to have vasoactive properties. In addition, the concentrations of amines in caecal contents of horses fed either grass or hay diets were compared. Fifteen amines were identified in equine hindgut contents in concentrations greater than 1 microM. The caecal concentrations of phenylethylamine, isoamylamine, cadaverine, diaminoheptane and spermidine were significantly higher in horses on spring/summer grass compared with those on winter grass or hay. These data show that many amines are present in the equine hindgut, some of which may have the potential to cause peripheral vasoconstriction if released into the circulation from the gastrointestinal tract. 相似文献
Chlamydophila abortus-DNA was detected using a touchdown enzyme time-release (TETR)-polymerase chain reaction (PCR) assay as an improved test for sensitive and rapid diagnosis of abortion in small ruminants. Two hundred and fifty two placentae, liver or spleen tissue samples from aborting ewes and goats or aborted lambs and kids in which C. abortus infection was suspected were examined by TETR-PCR and the results were compared with cell culture. Sixty-five tissue samples were found to be TETR-PCR positive while only 56 samples were cell culture-positive. After resolution of discrepant samples with a confirmatory nested PCR assay, TETR-PCR had a sensitivity of 97% and a specificity of 99.5% while culture had a sensitivity of 84.8% and a specificity of 100%. The analytical sensitivity of the TETR-PCR assay was determined with DNA extracted from 4-fold serial dilution of C. abortus B577 culture and found to be 0.25 inclusion-forming unit per PCR. No reduction in the analytical sensitivity was noted when the assay was tested with mouse liver samples spiked with 4-fold serial dilution of C. abortus B577 culture. No target product was amplified when DNA from Chlamydophila pecorum was tested. TETR-PCR used in this study is a practical, rapid, sensitive and specific assay that could be used for the detection of C. abortus in infected tissue samples. We recommend the use of this assay as a supplemental diagnostic tool for detection of C. abortus in infected tissue samples. 相似文献
Cyathostomins are important equine gastrointestinal parasites. Mass emergence of mucosal stage larvae causes a potentially fatal colitis. Mucosal stages are undetectable non-invasively. An assay that would estimate mucosal larval stage infection would greatly assist in treatment, control and prognosis. Previously, we identified two putative diagnostic antigens (20 and 25 kDa) in somatic larval preparations. Here, we describe their purification and antigen-specific IgG(T) responses to them. Western blots confirmed the purity of the antigens and showed that epitopes in the 20 kDa complex were specific to larval cyathostomins. No cross-reactive antigens appeared to be present in Parascaris equorum or Strongyloides westeri species. Low levels of cross-reactivity were observed in Strongylus edentatus and Strongylus vulgaris species. Use of purified antigens greatly reduced background binding in equine sera. These results indicate that both antigen complexes may be of use in a diagnostic assay. 相似文献
Maedi-visna virus (MVV) spreads horizontally via the respiratory route. In order to establish an experimental mucosal infection route, we compared intranasal and intratracheal inoculation using the infectious MVV molecular clone KV1772-kv72/67. For intranasal infection 0.5 x 10(3)-0.5 x 10(7) TCID50 of virus was sprayed into the nostrils of the sheep. For the intratracheal infection 10(0)-10(6) TCID50 of virus was injected into the trachea. Successful infection was indicated by development of MVV specific antibodies and virus isolation over a period of 6 months. In the intranasal infection, only the sheep receiving the highest dose i.e., 0.5 x 10(7) TCID50, became infected, suggesting that intranasal application was not an efficient mode of infection. In the intratracheal infection, the sheep infectious dose 50% was 10(1) TCID50 and virus could be isolated from the central nervous system 4 months post infection with 10(4) TCID50. Therefore it is concluded that intratracheal infection is a very efficient route for experimental inoculation with MVV. 相似文献
The discovery of Jenner in 1798 founded the science of immunology and eventually led to smallpox eradication from the earth in 1980 after a world-wide vaccination campaign with vaccinia virus (another poxvirus) and paradoxically, despite the eradication of smallpox, there has been an explosion of interest in vaccinia virus in the eighties. This interest has stemmed in part from the application of molecular genetics to clone and express foreign genes from recombinant vaccinia viruses. Vaccinia is also gaining renewed interest due to bioterrorism.
These recombinant viruses have multiple applications in research and vaccinology and led to the development of vectored vaccines, such as the recombinant vaccinia rabies vaccine used to eliminate rabies in Western Europe and, more recently, in the United States. Secondly, alternative poxvirus vectors, such as avipox viruses, were proved to be even safer and efficacious non-replicating vectors (suiciole vectors) when used in non-avian species. 相似文献
Vaccine approaches against AIDS have focused on inducing cellular immune responses, since many studies revealed the role of T cell responses in the control of human immunodeficiency virus or simian immunodeficiency virus (SIV) infections. The experimental infection of rhesus macaques with SIV or chimeric SHIV is routinely used as a model for AIDS. In such models, DNA immunization is a tool to elicit specific T cell responses and to study their protective efficacy. DNA immunogenicity in primates depends on parameters such as level of antigen expression, choice of the antigen among SIV proteins, use of fusion proteins, route of immunization, and addition of adjuvants. Recent results suggest that priming with DNA and boosting with attenuated recombinant viral vectors, each expressing corresponding SIV antigens, leads to improved specific immunity and, in some cases, affords protection against pathogenic challenge. After preclinical evaluations, DNA has entered clinical trials for a therapeutic or prophylactic gene-based AIDS vaccine. 相似文献
Ten pigs, aged 85 days, were vaccinated with a subunit vaccine containing 32 g of classical swine fever virus glycoprotein E2 (gp E2) (group 1), and a further 10 pigs were vaccinated with a C strain vaccine (104±0.15 TCID50/ml), produced by amplification in minipig kidney (MPK) cell culture (group 2). Nine non-vaccinated pigs served as a control group (group 3). Serum samples were collected before (day 0) and at 4, 10, 21 and 28 days after vaccination and were analysed by two commercially available enzyme immunoassays and by a neutralizing peroxidase-linked assay (NPLA). At the same times, peripheral blood was taken for determining the total leukocyte count and the body temperature was taken daily. Antibodies were not detected in serum samples collected before vaccination (day 0), and no side-effects that could be connected with vaccination were observed during the trial. Ten days after vaccination 6/10 pigs vaccinated with the subunit vaccine were seropositive. On days 21 and 28, the ratios of serologically positive to vaccinated pigs were 9/10 and 10/10, respectively. Four of the ten pigs that were vaccinated with the C strain vaccine were positive on day 21 and 9/10 on day 28. However, the results of the NPLA showed that only 4/10 pigs had an antibody titre >1:32 at the end of the trial in both the vaccinated groups, even though the subunit vaccine initiated an earlier and higher level of neutralizing antibodies than the vaccine produced from the C strain. Challenge was performed 28 days after vaccination on four randomly selected pigs from both vaccinated groups. The pigs survived the challenge without showing any clinical signs of classical swine fever (CSF), while two nonvaccinated control pigs died on the 10th and 12th days after infection. 相似文献
Bovine-leukosis virus (BLV; also termed ‘bovine-leukemia virus’) is a retrovirus that primarily affects lymphoid tissue of dairy and beef cattle. Our objective was to investigate the association between BLV infection and annual value of production (AVP) on dairy herds within the United States, as part of the USDA National Animal Health Monitoring System’s 1996 dairy study. 1006 herds (in 20 states) with at least 30 dairy cows were interviewed during 1996. The agar-gel immunodiffusion test was used to detect serum antibodies to BLV. 10–40 cows from each herd were tested and each tested cow was classified as negative or positive based on results of a single test.
A multivariable regression model was used with the 976 herds with complete data for analysis. When compared to herds with no test-positive cows, herds with test-positive cows produced 218 kg per cow (i.e. 3%) less milk. The average reduction in AVP was $ 59 per cow for test-positive herds relative to test-negative herds. For the dairy industry as a whole, BLV seropositivity was associated with loss to producers of $ 285 million and $ 240 million for consumers. Most of this $ 525 million industry loss was due to reduced milk production in test-positive herds. 相似文献