Salmonella Typhimurium ghost cells expressing K88ab, K88ac, K99, and FasA fimbriae of enterotoxigenic Escherichia coli (ETEC) in their envelopes were constructed. The genes encoding the fimbriae were individually cloned into an expression plasmid, pMMP81, carrying the asd gene, which was subsequently electroporated into the Δasd S. Typhimurium mutant. Plasmid pJHLP99, carrying the phiX174 lysis gene E, was also subsequently electroporated into the Salmonella mutant. The presence of the individual fimbriae on the ghost cells was examined by Western blot analysis. Forty BALB/c mice were equally divided into 2 groups of 20 mice each. Group A mice were intramuscularly vaccinated with a mixture of the 4 ghost cells expressing the individual fimbriae. The group B mice were inoculated with sterile phosphate-buffered saline as a control. The antigen-specific serum IgG concentrations were significantly higher in group A than in group B from week 2 until week 6 after inoculation. In addition, the antigen-specific IgA concentrations in fecal samples were significantly higher in group A than in group B at week 2 after inoculation. A large difference between the groups in the number of antigen-specific IgA-secreting cells in the small intestine was observed by immunohistochemical study. Also, the splenic lymphocyte proliferative responses were significantly greater in group A than in the control mice. These results suggest that vaccination with our Salmonella ghost cells can induce both humoral and cell-mediated immune responses and that the increased number of antigen-specific IgA-secreting cells in the small intestine may be correlated with the elevated fecal IgA immune response.

OBJECTIVE To compare blood pressure measured noninvasively with an oscillometric device that involved use of a novel conical cuff and a traditional cylindrical blood pressure cuff. ANIMALS 17 adult hound-type dogs. PROCEDURES Dogs were anesthetized, and a 20-gauge, 1.5-inch catheter was inserted in the median sacral artery. The catheter was attached to a pressure transducer via fluid-filled noncompliant tubing, and direct blood pressure was recorded with a multifunction monitor. A specially fabricated conical cuff was placed on the antebrachium. Four sets of direct and indirect blood pressure measurements were simultaneously collected every 2 minutes. Four sets of measurements were then obtained by use of a cylindrical cuff. RESULTS The cylindrical cuff met American College of Veterinary Internal Medicine consensus guidelines for validation of indirect blood pressure measurements for mean arterial blood pressure (MAP), systolic arterial blood pressure (SAP), and diastolic arterial blood pressure (DAP). The conical cuff met the consensus guidelines for difference of paired measurements, SD, and percentages of measurements within 10 and 20 mm Hg of the value for the reference method, but it failed a correlation analysis. In addition, although bias for the conical cuff was less than that for the cylindrical cuff for SAP, MAP, and DAP measurements, the limits of agreement for the conical cuff were wider than those for the cylindrical cuff for SAP and MAP measurements. CONCLUSIONS AND CLINICAL RELEVANCE On the basis of results of this study, use of a conical cuff for oscillometric blood pressure measurement cannot be recommended.

OBJECTIVE To compare the effects of equivalent volumes of equine plasma and 6% hydroxyethyl starch (600/0.75) solution (hetastarch) administered IV on plasma colloid osmotic pressure (pCOP) and commonly monitored clinicopathologic variables in horses. ANIMALS 6 healthy mares. PROCEDURES In a randomized, crossover study, horses were administered hetastarch or plasma (both 10 mL/kg, IV) 18 months apart. The pCOP and variables of interest were measured before (baseline), immediately after, and at intervals up to 96 or 120 hours after infusion. Prothrombin and activated partial thromboplastin times were measured before and at 2 and 8 hours after each infusion. RESULTS Prior to hetastarch and plasma infusions, mean ± SEM pCOP was 19.4 ± 0.5 mm Hg and 19.4 ± 0.8 mm Hg, respectively. In general, hetastarch and plasma infusions comparably increased pCOP from baseline for 48 hours, with maximum increases of 2.0 and 2.3 mm Hg, respectively. Mean Hct and hemoglobin, total protein, and albumin concentrations were decreased for a period of 72, 96, or 120 hours after hetastarch infusion with maximum decrements of 8.8%, 3.2 g/dL, 1.2 g/dL, and 0.6 g/dL, respectively. Plasma infusion decreased (albeit not always significantly) hemoglobin concentration and Hct for 20 and 24 hours (maximum changes of 1.5 g/dL and 6.6%, respectively) and increased total solids concentration (maximum change of 0.6 g/dL) for 48 hours. Platelet count and coagulation times were minimally affected. CONCLUSIONS AND CLINICAL RELEVANCE Overall, the hetastarch and plasma infusions comparably increased pCOP in healthy horses for up to 48 hours. Hetastarch induced greater, more persistent perturbations in clinicopathologic variables.

OBJECTIVE To evaluate the efficacy of IV administration of a product containing hyaluronan, sodium chondroitin sulfate, and N-acetyl-d-glucosamine for prevention or treatment of osteoarthritis in horses. ANIMALS 32 healthy 2- to 5-year-old horses. PROCEDURES The study involved 2 portions. To evaluate prophylactic efficacy of the test product, horses received 5 mL of the product (n = 8) or saline (0.9% NaCl) solution (8; placebo) IV every fifth day, starting on day 0 (when osteoarthritis was induced in the middle carpal joint of 1 forelimb) and ending on day 70. To evaluate treatment efficacy, horses received either the product or placebo (n = 8/treatment) on days 16, 23, 30, 37, and 44 after osteoarthritis induction. Clinical, diagnostic imaging, synovial fluid, gross anatomic, and histologic evaluations and other tests were performed. Results of each study portion were compared between treatment groups. RESULTS Limb flexion and radiographic findings were significantly worse for horses that received the test product in the prophylactic efficacy portion than for placebo-treated horses or product-treated horses in the treatment efficacy portion. In the prophylactic efficacy portion, significantly less articular cartilage erosion was identified in product-treated versus placebo-treated horses. In the treatment efficacy portion, joints of product-treated horses had a greater degree of bone edema identified via MRI than did joints of placebo-treated horses but fewer microscopic articular cartilage abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that caution should be used when administering the evaluated product IV to horses, particularly when administering it prophylactically, as it may have no benefit or may even cause harm.

OBJECTIVE To characterize the extent and location of atelectasis in healthy anesthetized dogs positioned in lateral recumbency and to determine whether repositioning dogs in sternal recumbency would resolve atelectasis. ANIMALS 6 healthy adult Beagles. PROCEDURES Each dog was anesthetized and underwent a CT examination twice with a 2-week interval between examinations. Once anesthetized, each dog was positioned in sternal recumbency, and a breath-hold helical transverse thoracic CT scan was acquired. The dog was then positioned in lateral recumbency for 30 minutes, and images were obtained at 5 preselected sites at 3, 8, 13, 20, and 30 minutes after repositioning (phase 1). Then, the dog was repositioned in sternal recumbency, and CT images were obtained at the 5 preselected sites at 5, 10, and 20 minutes after repositioning (phase 2). The protocol for the second examination was the same as the first except the dog was positioned in the opposite lateral recumbency during phase 1. The attenuation and cross-sectional area of the lung lobes at the preselected sites were measured and compared over time. RESULTS Lateral recumbency did not cause atelectasis in any of the dogs. Patchy areas of abnormally increased attenuation were infrequently detected in the left cranial lung lobe when dogs were positioned in left lateral recumbency, and those areas failed to resolve when dogs were positioned in sternal recumbency. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent of lung attenuation changes was minimal in healthy anesthetized Beagles positioned in lateral recumbency and should not preclude CT examination.

OBJECTIVE To determine the pharmacokinetics of a single dose of meloxicam after IM and oral administration to healthy lesser flamingos (Phoeniconaias minor) by use of a population approach. ANIMALS 16 healthy captive lesser flamingos between 1 and 4 years of age. PROCEDURES A single dose of meloxicam (0.5 mg/kg) was administered IM to each bird, and blood samples were collected from birds at 3 (n = 13 birds), 2 (2), or 1 (1) selected point between 0 and 13 hours after administration, with samples collected from birds at each point. After a 15-day washout period, the same dose of meloxicam was administered PO via a red rubber tube and blood samples were collected as described for IM administration. Pharmacokinetic values were determined from plasma concentrations measured by high-performance liquid chromatography. RESULTS Plasma drug concentrations after IM administration of meloxicam reached a mean ± SD maximum value of 6.01 ± 3.38 μg/mL. Mean area under the concentration-versus-time curve was 17.78 ± 2.79 μg•h/mL, and mean elimination half-life was 1.93 ± 0.32 hours. Plasma concentrations after oral administration reached a mean maximum value of 1.79 ± 0.33 μg/mL. Mean area under the curve was 22.16 ± 7.17 μg•h/mL, and mean elimination half-life was 6.05 ± 3.53 hours. CONCLUSIONS AND CLINICAL RELEVANCE In lesser flamingos, oral administration of meloxicam resulted in higher bioavailability and a longer elimination half-life than did IM administration, but the maximum plasma concentration was low and may be insufficient to provide analgesia in flamingos. Conversely, IM administration achieved the desired plasma concentration but would require more frequent administration.

OBJECTIVE To evaluate the validity of 2 radiographic methods for measurement of the tibial tuberosity advancement distance required to achieve a reduction in patellar tendon–tibial plateau angle (PTA) to the ideal 90° in dogs by use of the modified Maquet technique (MMT). SAMPLE 24 stifle joints harvested from 12 canine cadavers. PROCEDURES Radiographs of stifle joints placed at 135° in the true lateral position were used to measure the required tibial tuberosity advancement distance with the conventional (AM) and correction (AE) methods. The MMT was used to successively advance the tibial crest to AM and AE. Postoperative PTA was measured on a mediolateral radiograph for each advancement measurement method. If none of the measurements were close to 90°, the advancement distance was modified until the PTA was equal to 90° within 0.1°, and the true advancement distance (TA) was measured. Results were used to determine the optimal commercially available size of cage implant that would be used in a clinical situation. RESULTS Median AM and AE were 10.6 mm and 11.5 mm, respectively. Mean PTAs for the conventional and correction methods were 93.4° and 92.3°, respectively, and differed significantly from 90°. Median TA was 13.5 mm. The AM and AE led to the same cage size recommendations as for TA for only 1 and 4 stifle joints, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Both radiographic methods of measuring the distance required to advance the tibial tuberosity in dogs led to an under-reduction in postoperative PTA when the MMT was used. A new, more accurate radiographic method needs to be developed.

OBJECTIVE To determine the concentration of tilmicosin in mammary gland secretions of dairy cows following administration of an experimental preparation once or twice during the dry period (45-day period immediately prior to calving during which cows are not milked) and to evaluate its efficacy for the treatment of cows with intramammary infections (IMIs) caused by Staphylococcus aureus at dry off (cessation of milking; first day of dry period), compared with that of an intramammary infusion of ceftiofur. ANIMALS 172 cows. PROCEDURES Milk samples were collected for microbiological culture 5 days before dry off and at calving and 15 and 30 days after calving. Cows with Staphylococcus IMIs were randomly assigned to receive an experimental preparation of tilmicosin (20 mg/kg, SC) once at dry off (n = 58) or at dry off and again 20 days later (56) or receive a long-acting intramammary preparation of ceftiofur (500 mg/mammary gland; 56) at dry off. Mammary gland secretions were collected from 5 cows in the tilmicosin-treated groups every 5 days after dry off until calving for determination of tilmicosin concentration. RESULTS Mean maximum concentration of tilmicosin in mammary gland secretions ranged from 14.4 to 20.9 μg/mL after the first dose and was 17.1 μg/mL after the second dose. The bacteriologic cure rate was 100% for all 3 treatments. Tilmicosin was detectable for 0 and 18 days after calving in the milk of cows treated with 1 and 2 doses of tilmicosin, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Administration of an experimental preparation of tilmicosin (20 mg/kg, SC) once to dairy cows at dry off might be useful for the treatment of S aureus IMIs.

OBJECTIVE To determine whether extent of collateral circulation would change during temporary occlusion of the caudal vena cava (CVC) in ferrets (Mustela putorius), a pressure change would occur caudal to the occlusion, and differences would exist between the sexes with respect to those changes. ANIMALS 8 adult ferrets (4 castrated males and 4 spayed females). PROCEDURES Ferrets were anesthetized. A balloon occlusion catheter was introduced through a jugular vein, passed into the CVC by use of fluoroscopy, positioned cranial to the right renal vein, and inflated for 20 minutes. Venography was performed 5 and 15 minutes after occlusion. Pressure in the CVC caudal to the occlusion was measured continuously. A CBC, plasma biochemical analysis, and urinalysis were performed immediately after the procedure and 2 or 3 days later. RESULTS All 8 ferrets survived the procedure; no differences were apparent between the sexes. Vessels providing collateral circulation were identified in all ferrets, indicating blood flow to the paravertebral venous plexus. Complications observed prior to occlusion included atrial and ventricular premature contractions. Complications after occlusion included bradycardia, seizures, and extravasation of contrast medium. Mean baseline CVC pressure was 5.4 cm H2O. During occlusion, 6 ferrets had a moderate increase in CVC pressure (mean, 24.3 cm H2O) and 2 ferrets had a marked increase in CVC pressure to > 55.0 cm H2O. CONCLUSIONS AND CLINICAL RELEVANCE Caval occlusion for 20 minutes was performed in healthy ferrets with minimal adverse effects noted within the follow-up period and no apparent differences between sexes. The CVC pressure during occlusion may be prognostic in ferrets undergoing surgical ligation of the CVC, which commonly occurs during adrenal tumor resection.

OBJECTIVE To describe plasma pharmacokinetic parameters and tissue elimination of flunixin in veal calves. ANIMALS 20 unweaned Holstein calves between 3 and 6 weeks old. PROCEDURES Each calf received flunixin (2.2 mg/kg, IV, q 24 h) for 3 days. Blood samples were collected from all calves before the first dose and at predetermined times after the first and last doses. Beginning 24 hours after injection of the last dose, 4 calves were euthanized each day for 5 days. Plasma and tissue samples were analyzed by ultraperformance liquid chromatography. Pharmacokinetic parameters were calculated by compartmental and noncompartmental methods. RESULTS Mean ± SD plasma flunixin elimination half-life, residence time, and clearance were 1.32 ± 0.94 hours, 12.54 ± 10.96 hours, and 64.6 ± 40.7 mL/h/kg, respectively. Mean hepatic and muscle flunixin concentrations decreased to below FDA-established tolerance limits (0.125 and 0.025 μg/mL, respectively) for adult cattle by 3 and 2 days, respectively, after injection of the last dose of flunixin. Detectable flunixin concentrations were present in both the liver and muscle for at least 5 days after injection of the last dose. CONCLUSIONS AND CLINICAL RELEVANCE The labeled slaughter withdrawal interval for flunixin in adult cattle is 4 days. Because administration of flunixin to veal calves represents extralabel drug use, any detectable flunixin concentrations in edible tissues are considered a violation. Results indicated that a slaughter withdrawal interval of several weeks may be necessary to ensure that violative tissue residues of flunixin are not detected in veal calves treated with that drug.