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Результаты 91-100 из 420
Oral administration of sucrose solutions and measurement of serum sucrose concentrations to evaluate gastric permeability in adult bottlenose dolphins (Tursiops truncatus)
2006
Buddington, K.K. | Holmes, W.E. | Clemons-Chevis, C.L. | Solangi, M.A. | Vanderpool, D. | Buddington, R.K.
Objective-To measure concentrations of sucrose in the serum of captive dolphins after oral administration of a sucrose solution and determine the suitability of this method for use as a test to detect gastric ulcers. Animals-8 adult captive bottlenose dolphins (Tursiops truncatus). Procedures-Blood samples were collected from the ventral fluke vein of dolphins before and 45 minutes after oral administration of 500 mL of solution containing 25 or 50 g of sucrose; oral administration was achieved by use of gastric intubation. Serum was separated, diluted in a solution of 90% acetonitrile-to-10% water that contained 10 ng of an internal standard (trichlormethiazide)/microliter, mixed, and centrifuged. Supernatant was analyzed by use of liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS). Results-Serum sucrose concentrations of dolphins were at or less than the limits of detection before oral administration. Values after administration of sucrose solution varied among dolphins and were higher and more variable after administration of 50 g, compared with concentrations after administration of 25 g. Conclusions and Clinical Relevance-Serum sucrose concentrations in samples collected during routine health evaluations of captive dolphins can be reliably measured by use of LC-MS-MS. Correlating serum sucrose concentrations with endoscopic observations of the gastric mucosa of dolphins will validate this approach for use in screening for the prevalence and severity of gastric ulcers and determining the efficacy of treatment regimens.
Показать больше [+] Меньше [-]Phase I and pharmacokinetic evaluation of the combination of orally administered docetaxel and cyclosporin A in tumor-bearing dogs
2006
McEntee, M.C. | Rassnick, K.M. | Lewis, L.D. | Zgola, M.M. | Beaulieu, B.B. | Balkman, C.E. | Page, R.L.
Objective-To determine the maximum tolerated dose and characterize the pharmacokinetic disposition of an orally administered combination of docetaxel and cyclosporin A (CSA) in dogs with tumors. Animals-16 client-owned dogs with metastatic or advanced-stage refractory tumors. Procedures-An open-label, dose-escalation, single-dose, phase I study of docetaxel administered in combination with a fixed dose of CSA was conducted. Docetaxel (at doses of 1.5, 1.625, or 1.75 mg/kg) and CSA (5 mg/kg) were administered concurrently via gavage twice during a 3-week period. Plasma docetaxel concentrations were quantified by use of high-performance liquid chromatography, and pharmacokinetic disposition was characterized by use of noncompartmental analysis. Dogs' clinical signs and results of hematologic and biochemical analyses were monitored for evidence of toxicosis. Results-No acute hypersensitivity reactions were observed after oral administration of docetaxel. Disposition of docetaxel was dose independent over the range evaluated, and pharmacokinetic variables were similar to those reported in previous studies involving healthy dogs, with the exception that values for clearance were significantly higher in the dogs reported here. The maximum tolerated dose of docetaxel was 1.625 mg/kg. Gastrointestinal signs of toxicosis were dose limiting. Conclusions and Clinical Relevance-The absence of myelosuppression suggested that the docetaxel-CSA combination may be administered more frequently than the schedule used. Further studies are warranted to evaluate combination treatment administered on a biweekly schedule in dogs with epithelial tumors.
Показать больше [+] Меньше [-]Analysis of genetic mutations in the 7a7b open reading frame of coronavirus of cheetahs (Acinonyx jubatus)
2006
Kennedy, M.A. | Moore, E. | Wilkes, R.P. | Citino, S.B. | Kania, S.A.
Objective-To analyze the 7a7b genes of the feline coronavirus (FCoV) of cheetahs, which are believed to play a role in virulence of this virus. Sample Population-Biologic samples collected during a 4-year period from 5 cheetahs at the same institution and at 1 time point from 4 cheetahs at different institutions. Procedures-Samples were first screened for FCoV via a reverse transcription-PCR procedure involving primers that encompassed the 3'-untranslated region. Samples that yielded positive assay results were analyzed by use of primers that targeted the 7a7b open reading frames. The nucleotide sequences of the 7a7b amplification products were determined and analyzed. Results-In most isolates, substantial deletional mutations in the 7a gene were detected that would result in aberrant or no expression of the 7a product because of altered reading frames. Although the 7b gene was also found to contain mutations, these were primarily point mutations resulting in minor amino acid changes. The coronavirus associated with 1 cheetah with feline infectious peritonitis had intact 7a and 7b genes. Conclusions and Clinical Relevance-The data suggest that mutations arise readily in the 7a region and may remain stable in FCoV of cheetahs. In contrast, an intact 7b gene may be necessary for in vivo virus infection and replication. Persistent infection with FCoV in a cheetah population results in continued virus circulation and may lead to a quasispecies of virus variants.
Показать больше [+] Меньше [-]Pharmacokinetics of amoxicillin administered in drinking water to recently weaned 3- to 4-week-old pigs with diarrhea experimentally induced by Escherichia coli O149:F4
2006
Jensen, G.M. | Lykkesfeldt, J. | Frydendahl, K. | Moller, K. | Svendsen, O.
Objective-To measure effects of Escherichia coli O149:F4-induced diarrhea on water consumption and pharmacokinetics of amoxicillin after administration in drinking water. Animals-24 recently weaned 24- to 28-day-old crossbred pigs. Procedure-10 pigs were inoculated with E coli O149:F4; all 10 pigs subsequently developed diarrhea. Pigs were medicated by administration of amoxicillin in the drinking water (0.75 mg/mL) for a 4-hour period on 2 consecutive days. Fourteen age-matched noninfected healthy pigs (control group) were medicated in a similar manner. Blood samples were obtained from both groups daily, and plasma concentrations of amoxicillin were analyzed by use of high-performance liquid chromatography. Results-Diarrhea reduced the area under the plasma concentration-versus-time curve (AUC) and maximum plasma concentration (C(max)) of amoxicillin on the first day of medication by 56% and 63%, respectively. The AUC of amoxicillin on the second day of medication for diarrheic pigs did not differ significantly from that of control pigs on the first day of medication. Conclusions and Clinical Relevance-E coli-induced diarrhea reduced the AUC of amoxicillin and time that plasma concentration of amoxicillin was > 0.025 microgram/mL and, hence, less likely to have a therapeutic effect on the first day of administration in drinking water. On the assumption that plasma concentrations may indirectly reflect concentrations at the site of infection, analysis of our results suggests that higher doses of amoxicillin may be appropriate for administration in drinking water during a 4-hour period on the first day that pigs have diarrhea attributable to E coli O149:F4.
Показать больше [+] Меньше [-]Evaluation of dysregulation of the receptor tyrosine kinases Kit, Flt3, and Met in histiocytic sarcomas of dogs
2006
Zavodovskaya, R. | Liao, A.T. | Jones, C.L.R. | Yip, B. | Chien, M.B. | Moore, P.F. | London, C.A.
Objective-To evaluate canine histiocytic sarcoma cell lines and tumor samples for dysregulation of the Kit/stem-cell factor (SCF), Flt3/Flt3 ligand (Flt3L), and Met/hepatocyte growth factor (HGF) receptor tyrosine kinase signaling pathways, as these are known to contribute to the differentiation and survival of normal dendritic cells as well as malignant transformation of dendritic cells in mouse models. Sample Population-4 histiocytic sarcoma tumor cell lines and 35 formalin-fixed histiocytic sarcoma specimens obtained from dogs. Procedure-Histiocytic sarcoma cell lines were evaluated for expression of Kit/SCF, Flt3/Flt3L, and Met/HGF by use of reverse transcriptase-PCR procedures. Histiocytic sarcoma cell lines and tumor samples were evaluated for mutations in Kit, Flt3, and Met by use of PCR analysis of genomic DNA, followed by both sequencing and fluorescent PAGE for deletions or internal tandem duplications. The ability of the multitargeted split-kinase inhibitor SU11654 to block proliferation and induce apoptosis of histiocytic sarcoma cell lines was also evaluated. Results-No mutations in Kit, Flt3, and Met were identified in any of the cell lines or tumor samples evaluated. Furthermore, SU11654 did not induce cellcycle arrest or apoptosis of histiocytic sarcoma lines, even at supratherapeutic doses. Conclusions and Clinical Relevance-These data suggest that dysregulation of Kit/SCF, Flt3/Flt3L, and Met/HGF signaling pathways is unlikely to occur in histiocytic sarcomas of dogs and that inhibitors of the Kit, Flt3, and Met pathways are unlikely to provide clinical benefit to dogs with histiocytic sarcomas.
Показать больше [+] Меньше [-]Evaluation of changes in antimicrobial susceptibility patterns of Pasteurella multocida subsp multocida isolates from pigs in Spain in 1987-1988 and 2003-2004
2006
Vera Lizarazo, Y.A. | Rodriguez Ferri, E.F. | Martin de la Fuente, A.J. | Gutierrez Martin, C.B.
Objective-To determine the susceptibility of strains of Pasteurella multocida subsp multocida isolated from lung specimens of pigs with pneumonia to 20 antimicrobials and to evaluate the emergence of resistance to those antimicrobials in Spain during the past 2 decades. Sample Population-63 isolates recovered from 1987 to 1988 and 132 isolates recovered from 2003 to 2004. Procedure-A broth microdilution method was used to determine minimal inhibitory concentration (MIC) range and values for MIC50 and MIC90. Resistance of a strain to an antimicrobial agent was determined by use of the breakpoint value when available. Results-Isolates were generally susceptible to penicillin, ampicillin, ceftiofur, gentamicin, apramycin, neomycin, spectinomycin, chlortetracycline, erythromycin, tilmicosin, enrofloxacin, and florfenicol, and most isolates were resistant to clindamycin, tylosin tartrate, and tiamulin regardless of the time period. A substantial increase in resistance to sulfachlorpiridazine, sulfadimethoxine, sulfathiazole, and trimethoprim-sulfamethoxazole was observed, and a minor increase in resistance to oxytetracycline was also detected. Several multiresistance patterns were observed, most frequently among isolates recovered in the 2003 to 2004 interval. Conclusions and Clinical Relevance-Ceftiofur, florfenicol, and enrofloxacin are recommended for treatment of infections caused by P multocida subsp multocida in Spain. Increased frequency of resistance to oxytetracycline and sulfonamide drugs may be a contraindication for their use.
Показать больше [+] Меньше [-]In vitro mechanical evaluation of torsional loading in simulated canine tibiae for a novel hourglass-shaped interlocking nail with a self-tapping tapered locking design
2006
Dejardin, L.M. | Lansdowne, J.L. | Sinnott, M.T. | Sidebotham, C.G. | Haut, R.C.
Objective-To describe a novel interlocking nail (ILN) and locking system and compare the torsional properties of constructs implanted with the novel ILN or a standard 8-mm ILN (ILN8) by use of a gap-fracture model. Sample Population-8 synthetic specimens modeled from canine tibiae. Procedures-An hourglass-shaped ILN featuring a tapered locking mechanism was designed. A synthetic bone model was custom-made to represent canine tibiae with a 50-mm comminuted diaphyseal fracture. Specimens were repaired by use of a novel ILN or an ILN8 with screws. Specimens were loaded for torsional measurements. Construct compliance and angular deformation were compared. Results-Compliance of the ILN8 was significantly smaller than that of the novel ILN. Mean +/- SD maximum angular deformation of the ILN8 construct (23.12 +/- 0.65 degrees) was significantly greater, compared with that of the novel ILN construct (9.45 +/- 0.22 degrees). Mean construct slack for the ILN8 group was 15.15 +/- 0.63 degrees, whereas no slack was detected for the novel ILN construct. Mean angular deformation for the ILN8 construct once slack was overcome was significantly less, compared with that of the novel ILN construct. Conclusions and Clinical Relevance-Analysis of results of this study suggests that engineering of the locking mechanism enabled the novel hourglass-shaped ILN system to eliminate torsional instability associated with the use of current ILNs. Considering the potential deleterious effect of torsional deformation on bone healing, the novel ILN may represent a biomechanically more effective fixation method, compared with current ILNs, for the treatment of comminuted diaphyseal fractures.
Показать больше [+] Меньше [-]Urodynamic and morphologic changes in the lower portion of the urogenital tract after administration of estriol alone and in combination with phenylpropanolamine in sexually intact and spayed female dogs
2006
Hamaide, A.J. | Grand, J.G. | Farnir, F. | Le Couls, G. | Snaps, F.R. | Balligand, M.H. | Verstegen, J.P.
Objective-To compare the urodynamic and morphologic effects of the administration of estriol alone and in combination with phenylpropanolamine on the lower portion of the urogenital tract in female dogs. Animals-3 sexually intact and 3 spayed female Beagles without urinary incontinence. Procedure-Dogs received estriol (2 mg, PO) once daily for 7 days followed by estriol (2 mg, PO) and phenylpropanolamine (1.5 mg/kg, PO) once daily for 7 days. Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed before treatment (day 0) and at days 7 and 14. The maximum urethral pressure (MUP) and closure pressure (MUCP), urethral functional and anatomic profile lengths, integrated pressure (IP), plateau, distance before MUP, maximum meatus pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured. Results-Before treatment, no urodynamic differences were observed between the 2 groups; however, vaginal length and width were significantly shorter in spayed dogs. Compared with day 0 values, estriol treatment significantly increased MUP, MUCP, and IP values at day 7, but at day 14, this effect decreased despite phenylpropanolamine administration. No morphologic changes from baseline were detected after either treatment in any dog. Conclusions and Clinical Relevance-Data suggest that estriol mainly acts on the urethral sphincter mechanism by increasing urethral resistance in sexually intact and spayed female dogs without urinary incontinence. Administration of estriol and phenylpropanolamine did not increase the urethral resistance more than estriol alone. The urodynamic effects of estriol in female dogs with urinary incontinence remain to be elucidated.
Показать больше [+] Меньше [-]Infectivity of <i>Theileria parva</i> sporozoites following cryopreservation in four suspension media and multiple refreezing : evaluation by <i>in vitro</i> titration
2006
V. Mbao | D. Berkvens | T. Dolan | N. Speybroeck | J. Brandt | P. Dorny | P. Van den Bossche | T. Marcotty
Theileria parva sporozoite stabilates are used for immunizing cattle against East Coast fever and in in vitro sporozoite neutralization assays. In this study, we attempted to identify a cheaper freezing medium and quantified the infectivity loss of sporozoites due to refreezing of stabilates, using an in vitro technique. Pools of stabilates prepared using Minimum Essential Medium (MEM), Roswell Park Memorial Institute (RPMI 1640), foetal calf serum (FCS) and phosphate-buffered saline (PBS) were compared. All were supplemented with bovine serum albumin except the FCS. RPMI 1640 was as effective as MEM in maintaining sporozoite infectivity while the infectivity in PBS and FCS reached only 59 % and 67 %, respectively. In a second experiment, a stabilate based on MEM was subjected to several freeze-thaw cycles including various holding times on ice between thawing and refreezing. Refrozen stabilate gave an average sporozoite infectivity loss of 35 % per cycle. The results indicate that RPMI can be used as a cheaper freezing medium for T. parva stabilates and that refrozen stabilate doses need to be adjusted for the 35 % loss of infectivity.
Показать больше [+] Меньше [-]Treatment of natural ovine malignant theileriosis with a chloroform extract of the plant <i>Peganum harmala</i> : research communication
2006
M. Mirzaiedehaghi
One hundred sheep naturally infected with Theileria lestoquardi were treated with a chloroform extract of the plant Peganum harmala. The treatment was continued for 5 days, the dose of extract being 5 mg/kg per day. Sixty-five of the sheep responded to treatment and recovered but 35 did not and died. The cure rate was 65 %
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