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Toxicokinetics of norditerpenoid alkaloids from low larkspur (Delphinium andersonii) orally administered to cattle
2012
Green, Benedict T. | Welch, Kevin D. | Gardner, Dale R. | Stegelmeier, Bryan L. | Pfister, James A. | Cook, Daniel | Panter, Kip E.
Objective: To determine the toxicokinetics of N-(methylsuccinimido)anthranoyllycoctonine–type low larkspur alkaloids in beef cattle. Animals: 5 Black Angus steers and 35 Swiss Webster mice. Procedures: Low larkspur (Delphinium andersonii) was collected, dried, ground, and administered to 5 steers via oral gavage to provide a dose of 12 mg of N-(methylsuccinimido)-anthranoyllycoctonine alkaloids/kg. Steers were housed in metabolism crates for 96 hours following larkspur administration; heart rate was monitored continuously, and blood samples were collected periodically for analysis of serum concentrations of 16-deacetylgeyerline, methyllycaconitine, geyerline, and nudicauline and assessment of kinetic parameters. The LD50 of a total alkaloid extract from D andersonii was determined in Swiss Webster mice. Results: The alkaloids were quickly absorbed, with a maximum serum concentration achieved within 18 hours after administration. Geyerline and nudicauline coeluted as 1 peak and were considered together for toxicokinetic analysis. Mean ± SD elimination half-life was 18.4 ± 4.4 hours, 15.6 ± 1.5 hours, and 16.5 ± 5.1 hours for 16-deacetylgeyerline, methyllycaconitine, and geyerline and nudicauline, respectively. There were significant differences in maximum serum concentration, amount absorbed, and distribution half-life among the 4 alkaloids. The mouse LD50 was 9.8 mg/kg. Conclusions and Clinical Relevance: Results suggested that clinical poisoning was likely to be most severe approximately 18 hours after exposure. Cattle should be closely monitored for at least 36 hours after initial exposure. Additionally, a withdrawal time of approximately 7 days would be required to clear > 99% of the toxic alkaloids from the serum of cattle that have ingested low larkspur.
Mostrar más [+] Menos [-]Fractures in regions of adaptive modeling and remodeling of central tarsal bones in racing Greyhounds
2012
Bergh, Mary Sarah | Piras, Alessandro | Samii, Valerie F. | Weisbrode Steven E. | Johnson, Kenneth A.
Objective: To evaluate and compare bone modeling and remodeling in fractured and non-fractured central tarsal bones (CTBs) of racing Greyhounds. Sample: Paired cadaveric tarsi from 6 euthanized racing Greyhounds with right CTB fractures and 6 racing Greyhounds with other nontarsal injuries. Procedures: CTBs were dissected and fractured CTBs were reconstructed. Central tarsal bones were evaluated through standard and nonscreen high-detail radiography, computed tomography, and histologic examination. The bone mineral density (BMD) was calculated adjacent to fracture planes and as a gradient on sagittal computed tomographic images. Sagittal and transverse plane sections of bone were obtained and submitted for subjective histologic assessment. Linear mixed-effects models were used to compare findings. Results: Fractured right CTBs had greater BMD in the dorsal and midbody regions of the sagittal plane sections than did nonfractured CTBs. The BMD ratios from bone adjacent to the dorsal slab fracture planes were not different between fractured and nonfractured right CTBs. Conclusions and Clinical Relevance: Findings supported the existence of site-specific bone adaptation in CTBs of Greyhounds, with modeling and remodeling patterns that were unique to fractured right CTBs. The dorsal and midbody regions of fractured bones had greater BMD, and fractures occurred through these zones of increased BMD.
Mostrar más [+] Menos [-]Immunohistochemical and immunopathologic characterization of superficial stromal immune-mediated keratitis in horses
2012
Pate, Diana O. | Clode, Alison B. | Olivry, Thierry | Cullen, J. M. (John M) | Salmon, Jacklyn H. | Gilger, Brian C.
Objective: To describe the immunopathologic characteristics of superficial stromal immune-mediated keratitis (IMMK) immunopathologically by characterizing cellular infiltrate in affected corneas of horses. Animals: 10 client-owned horses with IMMK. Procedures: Immunohistochemical staining was performed on keratectomy samples with equine antibodies against the T-cell marker CD3 and B-cell marker CD79a (10 eyes) and the T-helper cytotoxic marker CD4 and T-cell cytotoxic marker CD8 (6 eyes). Percentage of positively stained cells was scored on a scale from 0 (no cells stained) to 4 (> 75% of cells stained). Equine IgG, IgM, and IgA antibodies were used to detect corneal immunoglobulin via direct immunofluorescence (10 eyes). Serum and aqueous humor (AH) samples from 3 horses with IMMK were used to detect circulating and intraocular IgG against corneal antigens via indirect immunofluorescence on unaffected equine cornea. Results: Percentage scores (scale, 0 to 4) of cells expressing CD3 (median, 2.35 [range, 0.2 to 3.7]; mean ± SD, 2.36 ± 1.08) were significantly greater than scores of cells expressing CD79a (median, 0.55 [range, 0 to 1.5]; mean, 0.69 ± 0.72). All samples stained positively for CD4- and CD8-expressing cells, with no significant difference in scoring. All samples stained positively for IgG, IgM, and IgA. No serum or AH samples collected from horses with IMMK reacted with unaffected equine cornea. Conclusions and Clinical Relevance: Pathogenesis of superficial stromal IMMK included cell-mediated inflammation governed by both cytotoxic and helper T cells. Local immunoglobulins were present in affected corneas; however, corneal-binding immunoglobulins were not detected in the serum or AH from horses with IMMK.
Mostrar más [+] Menos [-]Evaluation of factors that affect analytic variability of urine protein-to-creatinine ratio determination in dogs
2012
Rossi, Gabrielle | Giori, Luca | Campagnola, Simona | Zatelli, Andrea | Zini, Eric | Paltrinieri, Saverio
Objective: To determine whether preanalytic and analytic factors affect evaluation of the urinary protein-to-creatinine (UPC) ratio in dogs. Sample: 50 canine urine samples. Procedures: The UPC ratio was measured to assess the intra-assay imprecision (20 measurements within a single session), the influence of predilution (1:10, 1:20, and 1:100) for urine creatinine concentration measurement, and the effect of storage at room temperature (approx 20°C), 4°C, and −20°C. Results: The coefficient of variation at room temperature determined with the 1:20 predilution was < 10.0%, with the highest coefficients of variation found in samples with a low protein concentration or low urine specific gravity. This variability could result in misclassification of samples with UPC ratios close to the thresholds defined by the International Renal Interest Society to classify dogs as nonproteinuric (0.2), borderline proteinuric (0.21 to 0.50), or proteinuric (> 0.51). A proportional bias was found in samples prediluted 1:10, compared with samples prediluted 1:20 or 1:100. At room temperature, the UPC ratio did not significantly increase after 2 and 4 hours. After 12 hours at room temperature and at 4°C, the UPC ratio significantly increased. The UPC ratio did not significantly change during 3 months of storage at −20°C. Conclusions and Clinical Relevance: The intra-assay precision of the UPC ratio was sufficiently low to avoid misclassification of samples, except for values close to 0.2 or 0.5. The optimal predilution ratio for urine creatinine concentration measurement was 1:20. A 1:100 predilution is recommended in samples with a urine specific gravity > 1.030. The UPC ratio must be measured as soon as samples are collected. Alternatively, samples should be immediately frozen to increase their stability and minimize the risk of misclassification of proteinuria.
Mostrar más [+] Menos [-]Isolation and characterization of neural progenitor cells from adult canine brains
2012
Lim, Ji-Hey | Koh, Sehwon | Olby, Natasha J. | Piedrahita, Jorge | Mariani, Christopher L.
Objective: To isolate and characterize neural stem and progenitor cell populations in the brain of adult dogs. Animals: 7 healthy adult dogs. Procedures: Dogs (age, 10 to 60 months) were euthanized for reasons unrelated to the study. The subventricular zone (SVZ) adjacent to the lateral ventricles and subgranular zone (SGZ) of the hippocampus were isolated and used to generate single cell suspensions for nonadherent culture. The resulting primary neurospheres were serially passaged to assess self-renewal capacity. Neurospheres were differentiated by the withdrawal of growth factors and the addition of serum. Differentiated and undifferentiated neurospheres were analyzed via reverse transcriptase PCR assay or immunocytochemical staining for markers of pluripotency and neural lineage. Results: Neurospheres were generated from the SVZ and SGZ in all dogs. The SVZ generated more primary neurospheres than did the SGZ. Serial passage was successful, although few neurospheres could be generated after the fifth passage. Undifferentiated neurospheres were positive for SOX2, nestin, and glial fibrillary acidic protein (GFAP) and negative for OCT4 and NANOG. After differentiation, GFAP, neuronal class III β-tubulin, and 2′, 3′-cyclic nucleotide 3′-phosphodiesterase–positive progeny were noted migrating out of the neurospheres. Conclusions and Clinical Relevance: Results suggested the persistence of SOX2-positive, nestin-positive, GFAP-positive, OCT4-negative, and NANOG-negative neural progenitor cells in the SVZ and SGZ regions of mature canine brains, which are capable of producing multiple cell lineages. This study may serve as a basis for future studies investigating the role of these cells in various disease processes, such as neoplasia, or for regenerative purposes.
Mostrar más [+] Menos [-]Antimicrobial susceptibility and molecular subtypes of Staphylococcus aureus isolated from pig tonsils and cow’s milk in China
2012
Zhang, Chunping | Song, Li | Chen, Huijuan | Liu, Yang | Ning, Yibao | Qin, Yuling
This study investigated and compared the antimicrobial resistance patterns and ribotypes of Staphylococcus aureus isolated from pig tonsils and cow’s milk in China. A total of 90 isolates of S. aureus was included: 42 strains were isolated from tonsils of pigs and 48 from half-udder milk. The broth microdilution method and the double-disc diffusion test (D test) were used for antimicrobial susceptibility testing. The mecA gene for methicillin-resistant S. aureus (MRSA) and the ermA, ermB, ermC, and msrA genes for erythromycin-resistant strains were detected by polymerase chain reaction (PCR). The isolates were ribotyped with the Riboprinter system. The highest frequency of resistance was observed with clindamycin (91.1%), followed by penicillin (90.0%), and erythromycin (85.6%). All strains were susceptible to vancomycin and trimethoprim-sulfamethoxazole. The D test showed that 54.5% (42/77) of erythromycin-resistant isolates had the constitutive resistance phenotype and 45.5% (35/77) had the inducible resistance phenotype to clindamycin. A higher proportion of resistance to cephalosporins, macrolides, fluoroquinolones, and pleuromutilins was observed in pig isolates than in milk isolates (P < 0.05). The mecA gene was detected in all MRSA isolates; 89.6% of erythromycin-resistant strains harbored the ermC gene and 16.9% harbored the ermB gene. A total of 35 different ribogroups was found among the isolates investigated; 83.3% of pig strains belonged to 1 cluster with a similarity coefficient of 0.84. In contrast, 3 main clusters were observed among 68.8% of milk strains, which indicates a high degree of host specificity.
Mostrar más [+] Menos [-]Dose determination of fondaparinux in healthy cats
2012
Fiakpui, Nonya N. | Hogan, Daniel F. | Whittem, Ted | Green, Henry W III | Shipley, Eryn A. | Sederquist, Kimberly A.
Objective: To establish practical doses and administration frequencies of fondaparinux for cats that would approximate human therapeutic peak and trough plasma anti–factor Xa activities for thromboprophylaxis (TP) and thrombosis treatment (TT) protocols. Animals: 6 healthy adult purpose-bred cats. Procedures: Dosage protocols for TP and TT were selected on the basis of a single compartment pharmacokinetic model incorporating data from humans but modified to account for the higher body weight–normalized cardiac output of cats. Fondaparinux was administered at 0.06 mg/kg, SC, every 12 hours (TP) for 7 days in one session, and 0.20 mg/kg, SC, every 12 hours (TT) for 7 days in another, with a minimum of 1 week separating the sessions. Plasma anti–factor Xa activity was measured before fondaparinux administration (day 1) and at 2 (peak) and 12 (trough) hours after drug administration on days 1 and 7. Platelet aggregation and thromobelastographic (TEG) parameters were also measured 2 hours after drug administration on day 7. Results: Peak plasma anti–factor Xa activities on day 7 for TP (median, 0.59 mg/L; range, 0.36 to 0.77 mg/L) and TT (median, 1.66 mg/L; range, 1.52 to 2.00 mg/L) protocols were within therapeutic ranges for humans. However, only the TP protocol achieved trough anti–factor Xa activity considered therapeutic in humans (median, 0.19 mg/L; range, 0.00 to 0.37 mg/L) on day 7. There were significant changes in the TEG parameters at peak for the TT protocol, suggesting a hypocoagulable state. No significant changes in platelet aggregation were evident for either protocol. Conclusions and Clinical Relevance: A fondaparinux dosage of 0.06 or 0.20 mg/kg, SC, every 12 hours, was sufficient to achieve a peak plasma anti–factor Xa activity in cats that has been deemed therapeutic in humans. This study provided preliminary data necessary to perform fondaparinux dose-determination and clinical efficacy studies.
Mostrar más [+] Menos [-]Ticks (Acari: Ixodidae) infesting cattle and African buffaloes in the Tsavo conservation area, Kenya
2012
Edward K. Kariuki | Barend L. Penzhorn | Ivan G. Horak
Several ixodid tick species are shared between domestic cattle and African buffaloes (<em>Syncerus caffer</em>). So too, are a number of tick-borne diseases. The aim of the study was to compare the species composition of ticks that infest cattle and buffaloes utilising the same habitat within the Tsavo Conservation Area, Kenya. To this end, 25 cattle and 62 buffaloes were each opportunistically sampled for ticks on a single occasion in February 2010. Eight species, namely <em>Amblyomma gemma</em>, <em>Amblyomma lepidum</em>, <em>Hyalomma albiparmatum</em>, <em>Hyalomma rufipes</em>, <em>Hyalomma truncatum</em>, <em>Rhipicephalus evertsi evertsi</em>, <em>Rhipicephalus pravus</em> and <em>Rhipicephalus pulchellus</em> infested both cattle and buffaloes. Three species, <em>Rhipicephalus</em> (<em>Boophilus</em>) sp., <em>Rhipicephalus kochi</em>, and <em>Rhipicephalus muehlensi</em> were collected only from cattle, and three species,<em> Hyalomma impeltatum</em>, <em>Rhipicephalus humeralis</em> and<em> Rhipicephalus praetextatus</em> were present only on buffaloes. The attachment sites of the various tick species were also recorded. New locality records for <em>H. impeltatum</em> and <em>H. truncatum</em> and the first confirmed locality record for <em>Rhipicephalus praetextatus sensu stricto</em> in Kenya were documented.
Mostrar más [+] Menos [-]Immunogeno: Protective mechanism for Rift Valley fever in the Democratic Republic of Congo
2012
Georges Tshilenge
Rift Valley fever (RVF) is an acute, fever causing viral disease that affects domestic animals and humans. In Democratic Republic of Congo (DRC), this pathology is not well documented. No epidemic of the RVF has not been reported but sera samples collected in six provinces surveyed from 2005 to 2006 revealed 14% of apparent prevalence and, high apparent prevalence (20%) of antibodies against RVF virus was reported in Katanga Province during the same survey; this serological evidence was associated with abortions cases in Cattle (Mulumba et al. 2009). Livestock immunisation is important for control of Rift Valley fever virus (RVFV) epidemics; however immunisation of susceptible domestic animals in endemic countries does not protect animals against the clinical disease but prevents the propagation of virus to human population through reduction of the amplification degree in host animals. The humoral immunity is sufficient for protection for animals as well as for humans. The infection caused by RVFV leads to neutralisation of the immunity of the animal (Barnard 1979). Various immunological studies have been made on the characterisation of immune response during RVFV epidemics but, until now several studies have been concentrated on the response of the innate immune particularly based on signal interferon system than the response of the adaptive immune and cell mediated humoral immune. The available information on the immune response related to RVFV does not seem to provide enough information on various mechanisms of the response immune system. The aim of the study is based on mechanism of immune response system including protective effect of immunisation against RVFV. In addition, epidemiological and molecular studies will be assessed. As a matter of fact, following studies will be conducted: • evaluation of the immunological protection against Rift Valley fever in vaccinated and non- vaccinated cattle using IgG and IgM ELISAs in Katanga Province • assessment of cellular response to Rift Valley fever disease in vaccinated and naturally infected cattle • molecular characterisation of RVFV strains circulating in vaccinated and non vaccinated cattle • assessment of protective effect related to vaccinal strains in cattle, using a longitudinal survey. The studies will be carried out Northern Katanga Province within two areas, one with historyof circulation of RVFV and other without history RVFV circulation. Whole blood, spleen, liver, lymph node will be collected as target tissues from cattle carcasses. In addition, goats and sheeps samples will be collected alongside from each area in order to clarify the disease situation. Serological tests based on the detection of Ig M and Ig G will be used. DIVA tests, LAMP, and IHC techniques will be used. Within previously vaccinated areas in the above mentioned areas and those that are not vaccinated, the collected samples will be analysed using RT-PCR/RT-LAMP. In vitro experimental studies systems will be carried out using animal PMBCs that will be infected with wild type of RVF virus as well as with vaccinal strains, such as clones 13 and MP12 to characterise various cell types such as CD4 T cells, CD8 T cells, B-cells, NK cells and, macrophages will be studied with regard to activation and apoptosis signals on various post – infection days, using flow cytometry. A pool of animals will be vaccinated with the Clone 13 and another with the MP12 to determine the traceability. The monitoring of the immune response will be done through the measurement of immunoglobulin G (Ig G) and immunoglobulin M (Ig M). RT-PCR, spectrophotometer or Facs methods will be used for the dosage of cells T CD4 + and Cell T CD8+.
Mostrar más [+] Menos [-]‘One Health’ infectious diseases surveillance in Tanzania: Are we all on board the same flight?
2012
Erasto V. Mbugi | Kim A. Kayunze | Bugwesa Z. Katale | Sharon Kendall | Liam Good | Gibson S. Kibik | Julius D. Keyyu | Peter Godfrey-Faussett | Paul van Helden | Mecky I. Matee
Infectious diseases account for nearly 40% of the burden of human mortality and morbidity in low-income countries, of which 7% is attributable to zoonoses and 13% to recently emerging diseases from animals. One of the strategic approaches for effective surveillance, monitoring and control of infectious diseases compromising health in both humans and animals could be through a combination of multiple disciplines. The approach can be achieved through a joint effort from stakeholders comprising health professionals (medical and veterinary), social, economic, agricultural, environmental and other interested parties. With resource scarcity in terms of number of staff, skills and facility in low-income countries, participatory multi- sectoral and multidisciplinary approaches in limiting the burden of zoonotic diseases could be worthwhile. We review challenging issues that may limit the ‘One Health’ approach for infectious diseases surveillance in Tanzania with a focus on Health Policy and how best the human and animal health systems could be complemented or linked to suit the community in need for disease control under the theme’s context.
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