Antimicrobial-induced endotoxin and cytokine activity in an in vitro model of septicemia in foals     

Bentley AP  Barton MH  Lee MD  Norton NA  Moore JN 《American journal of veterinary research》2002,63(5):660-668

OBJECTIVE: To determine which antimicrobials that are used to treat neonatal foals with septicemia attributable to Escherichia coli will minimize endotoxin release from bacteria and subsequent activity of inflammatory mediators while maintaining bactericidal efficacy. SAMPLE POPULATION: Blood samples from 10 healthy foals. PROCEDURE: Escherichia coli isolates A and B were isolated from 2 septicemic foals, and minimal inhibitory concentrations (MIC) were determined for 9 antimicrobials. Five of these antimicrobials were tested in vitro at 2 and 20 times their respective MIC. Whole blood or mononuclear cells grown in tissue-culture media were incubated with 105 colony-forming units of E. coli and each antimicrobial or saline (0.9% NaCl) solution. After 6 hours, number of viable bacteria remaining was determined, and supernatant was tested for endotoxin and tumor necrosis activity. RESULTS: Testing in whole blood was compromised by bactericidal effects of the blood itself. In mononuclear cell suspensions, each antimicrobial significantly reduced the number of viable bacteria to low or undetectable amounts. Antimicrobials did not differ significantly in efficacy of bacterial killing. Amikacin used alone or in combination with ampicillin resulted in significantly less endotoxin activity than did ampicillin, imipenem, or ceftiofur alone. There was a correlation between TNF-alpha and endotoxin activity. CONCLUSIONS AND CLINICAL RELEVANCE: Aminoglycosides appear less likely to induce endotoxemia and TNF-alpha synthesis during bactericidal treatment of E. coli septicemia, compared with beta-lactam antimicrobials. Use of ampicillin, imipenem, or ceftiofur in the treatment of septicemic neonatal foals should be accompanied by appropriate treatment for endotoxemia.  相似文献   

Immunosuppression in specific-pathogen-free broilers administered infectious bursal disease virus vaccines by in ovo route     

Corley MM  Giambrone JJ 《Avian diseases》2002,46(4):810-815

The effect of two infectious bursal disease virus (IBDV) vaccines (IBDV-immune complex [Icx] and IBDV-2512), administered in ovo, on the cell-mediated immunity of specific-pathogen-free (SPF) broilers was examined. A decrease (P < 0.05) in the T-cell mitogenic response occurred in birds vaccinated with both vaccines on days 9 and 21 post in ovo vaccination (PIOV), but an increase (P < 0.05) occurred on day 15 PIOV. The T cells from birds given the IBDV-2512 were less responsive. There were no significant differences in proportions of lymphocytes expressing CT4+CT8 and CT8+CT4- except on day 21 PIOV, where an increase (P < 0.05) in IBDV-2512-vaccinated birds and a decrease (P < 0.05) in percentage of CT4+CT8- in IBDV-Icx-vaccinated birds was observed. There was an increase (P < 0.05) in percentage of CT8+CT4- T cells on day 21 PIOV in both vaccinated groups. A decrease (P < 0.05) in B-cell percentage was observed on day 21 PIOV in birds given both vaccines. Results indicated that although humoral immunosuppression is associated with destruction of B cells (bursal atrophy), cell-mediated immunosuppression induced by these two IBDV vaccines in SPF birds was not associated with altered helper (CT4+CT8-) or cytotoxic (CT8+CT4-) subpopulations of T lymphocytes.  相似文献   

Dorsal laminectomy for caudal cervical spondylomyelopathy: postoperative recovery and long-term follow-up in 20 dogs     

De Risio L  Muñana K  Murray M  Olby N  Sharp NJ  Cuddon P 《Veterinary surgery : VS》2002,31(5):418-427

OBJECTIVE: To evaluate the postoperative morbidity and long-term outcome of dogs after dorsal laminectomy for caudal cervical spondylomyelopathy (CCSM). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Twenty dogs with CCSM. METHODS: Medical records of dogs treated by dorsal laminectomy for CCSM at North Carolina State University and Colorado State University between 1989 and 1999 were reviewed. Information on signalment, onset, progression and duration of clinical signs, diagnostic testing, sites of dorsal laminectomy, postoperative complications, length of hospitalization, and the ambulatory status on discharge was recorded. A minimum follow-up of 7 months was required for inclusion in the study. Neurologic status was graded (0 to 5) preoperatively, 2 days after surgery, and at the time of the study (final score). Improvement or worsening of the neurologic status was assessed by comparison of different scores for each dog. Additional follow-up information was obtained by means of a detailed telephone questionnaire directed at both the owner and referring veterinarian. RESULTS: Mean duration of clinical signs before surgery was 4.9 months. At admission, 15 dogs were ambulatory and 5 were nonambulatory. Neurologic status worsened in 70% of dogs 2 days after surgery but improved in all but 1 dog over the long term. Mean time to optimal recovery was 3.6 months. Long-term follow-up ranged from 7 months to 9 years (mean +/- SD, 3.2 +/- 2.4 years). Four dogs had confirmed recurrence; 2 other dogs may have had recurrence. CONCLUSIONS: Dorsal cervical laminectomy is an effective treatment for CCSM in those dogs with dorsal compression or multiple sites of involvement. CLINICAL RELEVANCE: Although most dogs' neurologic status transiently worsened after surgery, long-term outcome and recurrence rates were comparable to those seen with other surgical techniques for CCSM.  相似文献   

Potential uses for geographic information system-based planning and decision support technology in intensive food animal production     

Colby MM  Johnson YJ 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2002,3(1):31-42

Although geographic information systems (GIS) have been used in many disciplines, the available technology in planning and decision support has only recently begun to be used in intensive animal production, in areas such as confined animal feeding operations. GIS-based planning and decision support systems have the potential to enhance many aspects of intensive animal production, such as disease monitoring and prevention, emergency management and nutrient waste disposal. Current uses of GIS in animal production are reviewed. Potential uses are illustrated using the example of the poultry industry on the Delmarva Peninsula, USA.  相似文献   

Fundamentals of host immune response against Brucella abortus: what the mouse model has revealed about control of infection     

Baldwin CL  Parent M 《Veterinary microbiology》2002,90(1-4):367-382

The studies reviewed here evaluated the role cellular immune system components play in control of brucellosis by conducting comparative studies with brucella-resistant C57BL/10 or C57BL/6 mice and susceptible BALB/c mice. We have shown by both in vitro and in vivo studies that activation of macrophages with interferon-gamma (IFN-γ) is an important factor for control of infection with B. abortus in the mouse model and that the mechanism of anti-brucella activity largely involved reactive oxygen intermediates. Differences in control of the organism by resistant and susceptible mice was not related to inherent differences in the ability of their macrophages to control infection either with or without IFN-γ activation nor was it attributable to NK cells since we found no role for them in control of brucellosis in either mouse strain. However, relative resistance to brucellosis did correlate with increased production of IFN-γ by CD4 T cells during the first weeks after infection while IL-10 contributed to susceptibility in BALB/c mice. Moreover, by 3 weeks post-infection splenocytes from the susceptible BALB/c mice failed to produce IFN-γ and relied on TNF- as well as CD8 T cells to control infection until the end of the plateau phase around 6 weeks post-infection when IFN-γ production resumed and clearance began. In contrast, IFN-γ was crucial for control throughout the infection in the more resistant C57BL/6 mice and the mice died in its absence by 6 weeks post-infection compared to 12 weeks for the more susceptible mice that relied on additional mechanisms of control. In contrast to the IFN-γ knock-out mice, both β2 microglobulin knock-out C57BL/6 mice, which do not express conventional MHC class I molecules and thus cannot present antigen to CD8 T cells, or perforin knock-out C57BL/6 mice, which have no T cell cytotoxic activity, controlled and cleared the infection as well as normal C57BL/6 mice. The hiatus of IFN-γ production in BALB/c mice correlated with very high levels of total IL-12 and it was postulated that the lack of IFN-γ was a consequence of p40 homodimer blocking activity. However, reduction of p40 IL-12 in vivo through administration of indomethacin reduced the infection without a concomitant measurable increase in IFN-γ. Current studies are aimed at elucidating the mechanism of the IFN-γ hiatus.  相似文献   

Preliminary observations of genetic susceptibility of elk (Cervus elaphus nelsoni) to chronic wasting disease by experimental oral inoculation.     

Amir N Hamir  Thomas Gidlewski  Terry R Spraker  Janice M Miller  Lynn Creekmore  Michelle Crocheck  Thomas Cline  Katherine I O'Rourke 《Journal of veterinary diagnostic investigation》2006,18(1):110-114

To compare the genetic susceptibility of elk (Cervus elaphus nelsoni) with various alleles of the PRNP gene, which encodes the normal cellular prion protein, to chronic wasting disease (CWD), eight 8-month-old elk calves of 3 genotypes (2 132MM, 2 132LM, and 4 132LL) were orally dosed with CWD-infected brain material from elk. During postinoculation (PI) month 23, both 132MM elk had lost appetite, developed clinical signs of weight loss and central nervous system (CNS) dysfunction, and were euthanized. Two other elk (both 132LM) developed similar clinical signs of disease and were euthanized during PI month 40. All 4 affected elk had microscopic lesions of spongiform encephalopathy (SE), and PrPres, the disease-associated form of the prion protein, was detected in their CNS and lymphoid tissues by use of immunohistochemical (IHC) and Western blot (WB) techniques. These findings indicate that elk with MM and LM at codon 132 are susceptible to orally inoculated CWD. All 4 LL elk are alive at PI year 4 and are clinically normal, which suggests that 132LL elk may have reduced susceptibility to oral infection with CWD-infected material or may have prolonged incubation time.  相似文献   

Diagnosis and management of a retrobulbar abscess of periapical origin in a domestic rabbit.     

Michelle L Ward 《Veterinary Clinics of North America: Exotic Animal Practice》2006,9(3):657-665

Retrobulbar abscessation is the most common orbital disease of rabbits, and the lesions are notoriously difficult to treat successfully. This article describes the diagnosis, surgical treatment, and long-term management of an extensive abscess located within the right maxilla and retrobulbar space of a domestic rabbit. Preoperative assessment and long-term monitoring were achieved with a combination of radiography, ophthalmic ultrasonography, and CT. Extraoral rigid endoscopy via a fenestration in the maxilla was used to facilitate surgical debridement of the lesion, and extraction of multiple cheek teeth has been fundamental to achieving control. The long-term use of topical and systemic antibiotic preparations and nonsteroidal anti-inflammatory medication is discussed.  相似文献   

Potential errors in measurement of nonuniform sap flow using heat dissipation probes   总被引：1，自引：0，他引：1  

Clearwater MJ  Meinzer FC  Andrade JL  Goldstein G  Holbrook NM 《Tree physiology》1999,19(10):681-687

The empirical calibration of Granier-type heat dissipation sap flow probes that relate temperature difference (DeltaT) to sap velocity (v) was reevaluated in stems of three tropical tree species. The original calibration was confirmed when the entire heated probe was in contact with conducting xylem, but mean v was underestimated when part of the probe was in contact with nonconducting xylem or bark. Analysis of the effects of nonuniform sap velocity profiles on heat dissipation estimates showed that errors increased as v and the proportion of the probe in nonconducting wood increased. If half of a 20-mm probe is in sapwood with a v of 0.15 mm s(-1) and the other half is in nonconducting wood, then mean v for the whole probe can be underestimated by as much as 50%. A correction was developed that can be used if the proportion of the probe in nonconducting wood is known. Even with the entire heated probe in contact with conducting xylem, v would be underestimated when radial velocity gradients are present. In this case, the error would be smaller except when velocity gradients are very steep, as can occur in species with ring-porous wood anatomy. Errors occur because the relationship between DeltaT and v is nonlinear. Mean DeltaT along the probe is therefore not a measure of mean v, and users of heat dissipation probes should not assume that v is integrated along the length of the probe. The same type of error can occur when DeltaT is averaged through time while v is changing, but the error is small unless there are sudden, step changes between zero and high sap velocity. It is recommended that relatively short probes (20 mm or less) be used and that probes longer than the depth of conducting sapwood be avoided. Multiple probes inserted to a range of depths should be used in situations where steep gradients in v are expected. If these conditions are met, heat dissipation probes remain useful and widely applicable for measuring sap flow in woody stems.  相似文献   

Soil carbon distribution and quality in a montane rangeland-forest mosaic in northern Utah     

Helga Van Miegroet  Janis L. Boettinger  Michelle A. Baker  Julia Nielsen  Dave Evans  Alex Stum 《Forest Ecology and Management》2005,220(1-3):284-299

Relatively little is known about soil organic carbon (SOC) dynamics in montane ecosystems of the semi-arid western U.S. or the stability of current SOC pools under future climate change scenarios. We measured the distribution and quality of SOC in a mosaic of rangeland-forest vegetation types that occurs under similar climatic conditions on non-calcareous soils at Utah State University's T.W. Daniel Experimental Forest in northern Utah: the forest types were aspen [Populus tremuloides] and conifer (mixture of fir [Abies lasiocarpa] and spruce [Picea engelmannii]); the rangeland types were sagebrush steppe [Artemisia tridentata], grass-forb meadow, and a meadow-conifer ecotone. Total SOC was calculated from OC concentrations, estimates of bulk density by texture and rock-free soil volume in five pedons. The SOC quality was expressed in terms of leaching potential and decomposability. Amount and aromaticity of water-soluble organic carbon (DOC) was determined by water extraction and specific ultra violet absorbance at 254 nm (SUVA) of leached DOC. Decomposability of SOC and DOC was derived from laboratory incubation of soil samples and water extracts, respectively.

Although there was little difference in total SOC between soils sampled under different vegetation types, vertical distribution, and quality of SOC appeared to be influenced by vegetation. Forest soils had a distinct O horizon and higher SOC concentration in near-surface mineral horizons that declined sharply with depth. Rangeland soils lacked O horizons and SOC concentration declined more gradually. Quality of SOC under rangelands was more uniform with depth and SOC was less soluble and less decomposable (i.e., more stable) than under forests. However, DOC in grass-forb meadow soils was less aromatic and more bioavailable, likely promoting C retention through cycling. The SOC in forest soils was notably more leachable and decomposable, especially near the soil surface, with stability increasing with soil depth. Across the entire dataset, there was a weak inverse relationship between the decomposability and the aromaticity of DOC. Our data indicate that despite similar SOC pools, vegetation type may affect SOC retention capacity under future climate projections by influencing potential SOC losses via leaching and decomposition.  相似文献   

Furunculosis in Atlantic salmon (Salmo salar L.) is not readily controllable by bacteriophage therapy     

David W. Verner&#x;Jeffreys  Myriam Algoet  Michelle J. Pond  Hardeep K. Virdee  Nicola J. Bagwell  Edward G. Roberts 《Aquaculture (Amsterdam, Netherlands)》2007,270(1-4):475-484

The potential of bacteriophage therapy to control bacterial disease in farmed fish was tested using, as an example, furunculosis of Atlantic salmon, caused by Aeromonas salmonicida subsp. salmonicida.

In vivo testing with Atlantic salmon and rainbow trout (Oncorhynchus mykiss Walbaum) showed no adverse effects, with bacteriophage generally cleared within 96 h of administration by either intraperitoneal (i.p.) injection or oral in-feed.

Juvenile Atlantic salmon were administered a combination of bacteriophage O, R and B (1.9 × 10⁸ pfu fish^− 1) by i.p. injection, after they had been challenged with A. salmonicida subsp. salmonicida 78027, also by i.p. injection. The fish that were injected with bacteriophage immediately after challenge died at a significantly slower rate then those that were either not treated with bacteriophage, or treated 24 h post-challenge. However, the end result (100% mortality) was not affected.

In further experiments the effects of oral (1.88 × 10⁵ pfu g^− 1 fish^− 1 daily for 30 days), bath (1.04 × 10⁵ ml^− 1 daily for 30 days) and i.p. (6.25 × 10⁷ pfu fish^− 1) phage treatment to control furunculosis in experimentally infected Atlantic salmon were compared with antibiotherapy (treatment with 10 mg kg^− 1 bw^− 1 day^− 1 oxolinic acid for 10 days), using an indirect cohabitation challenge. No protection was offered by any of the bacteriophage treatments, compared to the positive challenge group, although significant protection was offered by the oxolinic acid treatment. Analysis of samples taken from the trials demonstrated that bacteriophage were correctly administered to the fish and, on occasion, were isolated from fish that had succumbed to furunculosis. It was also shown that bacteriophage resistant A. salmonicida subsp. salmonicida isolates could be recovered from mortalities in all the treatment groups.

The results suggest that, although there were no safety problems associated with the approach, furunculosis in Atlantic salmon is not readily controllable by application of bacteriophage.  相似文献