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Abstract

OBJECTIVE To determine and compare the effect of hoof boots (HBs) and shoes with a toe extension on stance duration, ground reaction force, and sole length in contact with the ground in nonlame horses during walking.

ANIMALS 6 nonlame Standardbreds.

PROCEDURES Force plate gait analyses of the forelimbs were performed while the horses were walking barefoot before manipulation of feet (baseline), while the horses were walking fitted with HBs, while the horses were walking shod with toe-extension shoes, and while the horses were walking barefoot after shoe removal. Horses underwent radiography of both forelimb feet to determine the sole length in contact with the ground when barefoot, wearing HBs, and shod with toe-extension shoes. Stance duration, ground reaction force, and sole length were compared among the various walking sessions.

RESULTS Compared with baseline findings, stance duration increased significantly when horses were fitted with HBs (7%) or toe-extension shoes (5%). Peak forelimb ground reaction force was similar among walking sessions; however, time of braking force peak was significantly greater during the stance phase only when horses wore HBs. Also, the sole length in contact with the ground was significantly longer in horses fitted with HBs (14.3 cm) or shod with the toe-extension shoes (17.6 cm), compared with that for one of the barefoot hooves (12.7 cm).

CONCLUSIONS AND CLINICAL RELEVANCE In nonlame horses, use of HBs prolonged the stance time and time of braking force peak, which is indicative of a slower deceleration phase during limb impact with the ground. Also, the use of HBs prolonged the deceleration phase of the stride and increased the sole length in contact with the ground.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To characterize spatial release of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CI-CSH) beads by use of an agarose tissue phantom.

SAMPLE 3-mm-diameter beads (n = 60) containing 4.6 mg of carboplatin (2.4 mg of platinum)/bead.

PROCEDURES 18 L of 1% agarose was prepared and poured into 36 containers (10 × 10 × 10 cm), each of which was filled half full (0.5 L/container). After the agarose solidified, 1, 3, 6, or 10 CI-CSH beads were placed on the agar in defined patterns. An additional 36 blocks of agar (0.5 L/block) were placed atop the beads, positioning the beads in the center of 1 L of agar. The experiment was replicated 3 times for each bead pattern for 24, 48, and 72 hours. At these times, representative agarose blocks were sectioned in the x-, y-, and z-planes and labeled in accordance with their positions in shells radiating 1, 2, 3, 4, and 5 cm from the center of the blocks. Agarose from each shell was homogenized, and a sample was submitted for platinum analysis by use of inductively coupled plasma–mass spectroscopy.

RESULTS Platinum diffused from CI-CSH beads at predicted anticancer cytotoxic concentrations for 2 to 5 cm.

CONCLUSIONS AND CLINICAL RELEVANCE Results provided information regarding the spatial distribution of platinum expected to occur in vivo. Agarose may be used as a diffusion model, mimicking the characteristics of subcutaneous tissues. Measured platinum concentrations might be used to guide patterns for implantation of CI-CSH beads in animals with susceptible neoplasms.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate effects of intracameral injection of preservative-free 1% and 2% lidocaine hydrochloride solution on the anterior segment of the eyes in dogs.

Animals—16 adult healthy dogs (8 male and 8 female) judged to be free of ocular disease.

Procedure—Dogs were randomly assigned to 2 groups of 8 dogs each. Group 1 dogs received an intracameral injection of 0.10 mL of preservative-free 1% lidocaine solution in the designated eye, and group 2 dogs received 0.10 mL of preservative-free 2% lidocaine solution in the designated eye. After injection, intraocular pressure was measured every 12 hours for 48 hours and then every 24 hours until 168 hours after injection. Slit-lamp biomicroscopy was performed preceding intracameral injection, 8 hours after injection, and then every 24 hours until 168 hours after injection. Ultrasonic pachymetry and specular microscopy were performed preceding intracameral injection and 72 and 168 hours after injection. Corneal thickness and endothelial cell density and morphology were compared with baseline measurements.

Results—No significant differences were found in intraocular pressure, corneal thickness, endothelial cell density, and morphologic features in either group, compared with baseline. A significant difference in aqueous flare was found for treated and control eyes 8, 24, and 48 hours after injection, compared with baseline. No significant difference in aqueous flare was found between treated and control eyes within either group.

Conclusions and Clinical Relevance—No adverse ocular effects were detected after intracameral injection of preservative-free 1% or 2% lidocaine solution; thus, its use would be safe for intraocular pain management in dogs. (Am J Vet Res 2004;65:1325–1330)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To screen for expression of 9 predominant members of the matrix metalloproteinase (MMP) family, including membrane-type matrix metalloproteinases (MT-MMPs) and tissue inhibitors of metalloproteinases (TIMPs), in primary tumor tissue biopsy specimens of vaccine site-associated sarcomas (VSS) in cats and compare expression profiles of VSS with expression profiles of non-VSS and carcinomas.

Sample Population—31 primary tumor tissue biopsy specimens and 6 nontumor (normal) tissue biopsy specimens.

Procedure—Tissue specimens were obtained from primary tumor biopsy specimens of cats. Primers for reverse transcriptase-polymerase chain reaction assay were designed on the basis of known sequences. Data were analyzed for patterns of expression of MMPs, MT-MMPs, and TIMPs. Differences in expression patterns were evaluated among cats of differing genders, ages, metastasis status, and overall survival durations, and between cats with VSS and cats with non-VSS tumor types.

Results—A total of 31 primary tumor tissue biopsy specimens and 6 nontumor (normal) tissue biopsy specimens were screened for the presence of 6 MMPs and 3 TIMPs. Matrix metalloproteinase and TIMP expression was found in non-VSS, carcinomas, and VSS. No significant differences were found in patterns of expression among tumor types. Metastasis was found to be the only predictive factor for overall survival duration. A significant correlation was found between MMP2 and MT-MMP16 expression and overall duration of survival.

Conclusions and Clinical Relevance—The identification of MMPs in feline VSS supports an underlying inflammatory pathogenesis for this tumor. Expression of MMP2 and MT-MMP16 were correlated with survival time in our study. ( Am J Vet Res 2004; 65:373–379)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare the mechanical properties of laryngeal tie-forward (LTF) surrogate constructs prepared with steel fixtures and No. 5 braided polyester or braided polyethylene by use of a standard or a modified suture placement technique.

Sample—32 LTF surrogate constructs.

Procedures—Surrogate constructs were prepared with steel fixtures and sutures (polyester or polyethylene) by use of a standard or modified suture placement technique. Constructs underwent single-load-to-failure testing. Maximal load at failure, elongation at failure, stiffness, and suture breakage sites were compared among constructs prepared with polyester sutures by means of the standard (n = 10) or modified (10) technique and those prepared with polyethylene sutures with the standard (6) or modified (6) technique.

Results—Polyethylene suture constructs had higher stiffness, higher load at failure, and lower elongation at failure than did polyester suture constructs. Constructs prepared with the modified technique had higher load at failure than did those prepared with the standard technique for both suture materials. All sutures broke at the knot in constructs prepared with the standard technique. Sutures broke at a location away from the knot in 13 of 16 constructs prepared with the modified technique (3 such constructs with polyethylene sutures broke at the knot).

Conclusions and Clinical Relevance—Results suggested LTF surrogate constructs prepared with polyethylene sutures or the modified technique were stronger than those prepared with polyester sutures or the standard technique.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To compare the mechanical properties of laryngeal tie-forward (LTF) constructs prepared with different suture materials and suture placement patterns during single load to failure testing.

SAMPLE Larynges harvested from 50 horse cadavers and 5 intact horse cadavers.

PROCEDURES In vitro LTF constructs were created by a standard technique with polyester sutures, a standard technique with polyethylene sutures, a modified technique with metallic implants and polyester sutures, a modified technique with metallic implants and polyethylene sutures, or a modified tie-off technique with polyester sutures (10 of each type of construct). Mechanical properties including maximal load (N) at failure and failure mode were compared among constructs. Also, maximal loads at failure of the in vitro LTF constructs were compared with the loads exerted on the sutures tightened to achieve rostral laryngeal advancement in intact cadavers.

RESULTS Constructs prepared by a standard technique with polyethylene sutures had a significantly higher pull out strength than those prepared by a modified technique with metallic implants and either polyester or polyethylene sutures. For constructs prepared by a standard technique with polyethylene sutures or similarly placed polyester sutures, maximal load at failure did not differ but the failure mode did differ significantly. The load to failure for all in vitro constructs was higher than the maximal load measured during a range of motion test in intact horse cadavers.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that LTF procedures can be performed in live horses with any of the suture materials and techniques tested.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To characterize the pharmacokinetics of a clinically relevant dose of misoprostol administered PO or per rectum (PR) to horses.

ANIMALS

8 healthy adult horses.

PROCEDURES

In a randomized 3-way crossover design, horses received a single dose of misoprostol (5 μg/kg) administered PO (with horses fed and unfed) and PR, with a minimum 3-week washout period separating the experimental conditions. Blood samples were obtained before and at various points after drug administration (total, 24 hours), and plasma concentrations of misoprostol free acid were measured.

RESULTS

Mean maximum plasma concentration of misoprostol was significantly higher in the PR condition (mean ± SD, 967 ± 492 pg/mL) and unfed PO condition (655 ± 259 pg/mL) than in the fed PO condition (352 ± 109 pg/mL). Mean area under the concentration-versus-time curve was significantly lower in the PR condition (219 ± 131 pg•h/mL) than in the unfed (1,072 ± 360 pg•h/mL) and fed (518 ± 301 pg•h/mL) PO conditions. Mean time to maximum concentration was ≤ 30 minutes for all conditions. Mean disappearance half-life was shortest in the PR condition (21 ± 29 minutes), compared with values for the unfed (170 ± 129 minutes) and fed (119 ± 51 minutes) PO conditions. No adverse effects were noted.

CONCLUSIONS AND CLINICAL RELEVANCE

Misoprostol was rapidly absorbed and eliminated regardless of whether administered PO or PR to horses. Rectal administration may be a viable alternative for horses that cannot receive misoprostol PO, but this route may require more frequent administration to maintain therapeutic drug concentrations.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare measurements of left ventricular volume and function derived from 2-D transthoracic echocardiography (2DE), transesophageal echocardiography (TEE), and the ultrasound velocity dilution cardiac output method (UDCO) with those derived from cardiac MRI (cMRI) in healthy neonatal foals.

ANIMALS

6 healthy 1-week-old Standardbred foals.

PROCEDURES

Foals were anesthetized and underwent 2DE, TEE, and cMRI; UDCO was performed simultaneously with 2DE. Images acquired by 2DE included the right parasternal 4-chamber (R4CH), left apical 4- and 2-chamber (biplane), and right parasternal short-axis M-mode (M-mode) views. The longitudinal 4-chamber view was obtained by TEE. Measurements assessed included left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV), ejection fraction, stroke volume (LVSV), cardiac output (CO), and cardiac index (CI). Bland-Altman analyses were used to compare measurements derived from biplane, R4CH, and M-mode images and UDCO with cMRI-derived measurements. Repeatability of measurements calculated by 3 independent reviewers was assessed by the intraclass correlation coefficient.

RESULTS

Compared with cMRI, all 2DE and TEE modalities underestimated LVEDV and LVESV and overestimated ejection fraction, CO, and CI. The LVSV was underestimated by the biplane, R4CH, and TEE modalities and overestimated by UDCO and M-mode methods. However, the R4CH-derived LVSV, CO, and CI were clinically comparable to cMRI-derived measures. Repeatability was good to excellent for measures derived from the biplane, R4CH, M-mode, UDCO, and cMRI methods and poor for TEE-derived measures.

CONCLUSIONS AND CLINICAL RELEVANCE

All assessed modalities yielded clinically acceptable measurements of LVEDV, LVESV, and function, but those measurements should not be used interchangeably when monitoring patient progress.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether conscious, unsedated cats will inhale a nebulized material administered via a facemask and whether this material will reach the lower airways.

Animals—20 healthy adult cats.

Procedure—Technetium Tc 99m-diaminetriaminopentaacetic acid (99mTc-DTPA) was nebulized into a spacer and administered to the cats via a closely fitting facemask. By use of a gamma camera, images were then immediately obtained to determine the distribution of 99mTc-DTPA within the lower airways.

Results—Images obtained by use of the gamma camera revealed that all 20 cats had inhaled 99mTc-DTPA from the facemask. In each cat, deposition of the radiopharmaceutical agent was evident throughout the lung fields.

Conclusions and Clinical Relevance—Awake cats that were not used to the application of a facemask did inhale substances from such a device. Aerosolization of medications may be a feasible route of administration for cats with lower airway disease. (Am J Vet Res 2004;65:806–809)

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in American Journal of Veterinary Research

Abstract

Objective—To isolate and characterize the cDNA sequence of canine stromelysin-1 (matrix metalloproteinase [MMP]-3), screen various naturally developing primary tumors of dogs, and assess the effect of stromelysin-1 on survival of dogs with cancer.

Sample Population—3 canine cell lines and biopsy specimens of primary tumors collected from 54 dogs.

Procedure—3 canine cell lines and biopsy specimens of primary tumors collected from 54 dogs at the University of Illinois Veterinary Teaching Hospital were used in the study. Primer sets based on human stromelysin-1 and consensus sequences were designed for expression, screening, and isolation. Two additional primer sets were designed for screening. Samples were assayed at least in duplicate. Data were analyzed for differences in expression of stromelysin-1 on the basis of sex, age, metastasis, malignant versus nonmalignant tissue origin, and duration of patient survival.

Results—A 1,479-bp cDNA nucleotide sequence was amplified from established canine cell lines. The open reading frame encoded a protein consisting of 478 amino acids. This sequence was 70% to 88% homologous with stromelysin-1 of other species at the amino acid level. Fifty-four samples were screened for stromelysin-1. Of these, 34 (63%) had positive results and 20 (37%) had negative results for expression. Stromelysin-1 and metastasis were associated with a poor prognosis for survival.

Conclusions and Clinical Relevance—Stromelysin-1 is a potential activator of other members of the MMP family. Additional studies are needed to investigate the relationship between stromelysin-1 production and aggressive biological behavior of tumors in dogs. (Am J Vet Res 2005;66:1526–1535)

Full access
in American Journal of Veterinary Research