Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Michael Walker x
  • Refine by Access: All Content x
Clear All Modify Search
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the correlation between halftime of liquid-phase gastric emptying (T50), determined with nuclear scintigraphy using technetium Tc 99m pentetate, and absorption variables of orally administered acetaminophen.

Animals—6 mature horses.

Procedure—Technetium Tc 99m pentetate (10 mCi) and acetaminophen (20 mg/kg of body weight) were administered simultaneously in 200 ml of water. Serial left and right lateral images of the stomach region were obtained with a gamma camera, and T50 determined separately for counts obtained from the left side, the right side and the geometric mean. Power exponential curves were used for estimation of T50 and modified R2 values for estimation of goodness of fit of the data. Serial serum samples were taken, and acetaminophen concentration was determined, using fluorescence polarization immunoassay. Maximum serum concentration (Cmax), time to reach maximum serum concentration (Tmax), area under the curve for 240 minutes and the absorption constant (Ka) were determined, using a parameter estimation program. Correlations were calculated, using the Spearman rank correlation coefficient.

Results—Correlations between T50 and Tmax and between T50 and Ka were significant.

Conclusions and Clinical Relevance—Tmax and Ka are valuable variables in the assessment of liquidphase gastric emptying using acetaminophen absorption. Acetaminophen absorption may be a valuable alternative to nuclear scintigraphy in the determination of gastric emptying rates in equine patients with normally functioning small intestine. (Am J Vet Res 2000;61:310–315)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the association between spondylosis deformans and clinical signs of intervertebral disk disease (IVDD) in dogs.

Design—Retrospective case series.

Animals—210 dogs.

Procedure—Records of 172 dogs with clinical signs of IVDD and 38 dogs with other neurologic disorders were reviewed. Signalment, sites of spondylosis, severity of associated osteophytosis, type of disk herniation, and duration of signs were recorded.

Results—Dogs with IVDD had significantly fewer sites of involvement and lower grades of spondylosis deformans, compared with those in the non-IVDD group. When groups were adjusted for age and weight via multivariate linear regression, there were no differences in severity of osteophytosis or number of affected sites. Dogs with type II disk disease had higher numbers of affected sites and more severe changes, compared with dogs with type I disk herniation. There was no difference between groups in the rate at which IVDD was diagnosed at sites of spondylosis, compared with the rate at which IVDD was diagnosed in unaffected disk spaces. Areas of spondylosis were closer to sites of IVDD that elicited clinical signs than to randomly chosen intervertebral spaces, and distances between sites of spondylosis and sites of IVDD had a bimodal appearance.

Conclusions and Clinical Relevance—An association may exist between radiographically apparent spondylosis and type II disk disease; type I disk disease was not associated with spondylosis. Spondylosis in radiographs of dogs with suspected type I disk disease is not clinically important. Spatial associations among sites of spondylosis and sites of IVDD may be coincidental or associated with vertebral column biomechanics.

Full access
in Journal of the American Veterinary Medical Association

OBJECTIVE

To describe surgical management and associated outcomes for dogs with primary spontaneous pneumothorax.

ANIMALS

110 client-owned dogs with primary spontaneous pneumothorax that underwent surgical management.

PROCEDURES

Medical records at 7 veterinary teaching hospitals were reviewed. Data collected included signalment, history, clinical signs, radiographic and CT findings, surgical methods, intraoperative and postoperative complications, outcomes, and histopathologic findings. Follow-up information was obtained by contacting the referring veterinarian or owner.

RESULTS

110 dogs were included, with a median follow-up time of 508 days (range, 3 to 2,377 days). Ninety-nine (90%) dogs underwent median sternotomy, 9 (8%) underwent intercostal thoracotomy, and 2 (2%) underwent thoracoscopy as the sole intervention. Bullous lesions were most commonly found in the left cranial lung lobe (51/156 [33%] lesions) and right cranial lung lobe (37/156 [24%] lesions). Of the 100 dogs followed up for > 30 days, 13 (13%) had a recurrence of pneumothorax, with median time between surgery and recurrence of 9 days. Recurrence was significantly more likely to occur ≤ 30 days after surgery, compared with > 30 days after surgery. Recurrence > 30 days after surgery was rare (3 [3%]). No risk factors for recurrence were identified.

CONCLUSIONS AND CLINICAL RELEVANCE

Lung lobectomy via median sternotomy resulted in resolution of pneumothorax in most dogs with primary spontaneous pneumothorax. Recurrence of pneumothorax was most common in the immediate postoperative period, which may have reflected failure to identify lesions during the initial thoracic exploration, rather than development of additional bullae.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To optimize the isolation and culture of mesenchymal stem cells (MSCs) from umbilical-cord blood (UCB), identify variables that predicted successful MSC isolation, and determine whether shipping, processing, and cryopreservation altered MSC viability, recovery rates, and expansion kinetics.

Sample Population—UCB samples from 79 Thoroughbred and Quarter Horse mares.

Procedures—UCB samples were processed to reduce volume and remove RBCs. Nucleated cells (NCs) were cryopreserved or grown in various culture conditions to optimize MSC monolayer expansion and proliferation. Donor and UCB-sample factors were analyzed to determine their influence on the success of MSC isolation and monolayer expansion.

Results—MSCs capable of multilineage in vitro differentiation were expanded from > 80% of UCB samples. Automated UCB processing and temperature-controlled shipping facilitated sterile and standardized RBC reduction and NC enrichment from UCB samples. The number of NCs after UCB samples were processed was the sole variable that predicted successful MSC expansion. The UCB-derived MSCs and NCs were successfully cryopreserved and thawed with no decrease in cell recovery, viability, or MSC proliferation. The use of fibronectin-coated culture plates and reduction of incubator oxygen tension from 20% to 5% improved the MSC isolation rate. Some UCB-derived MSC clones proliferated for > 20 passages before senescence. Onset of senescence was associated with specific immunocytochemical changes.

Conclusions and Clinical Relevance—Equine UCB samples appeared to be a rich source of readily obtainable, highly proliferative MSCs that could be banked for therapeutic use.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine clinical, radiographic, and scintigraphic abnormalities in and treatment and outcome of horses with trauma-induced osteomyelitis of the proximal aspect of the radius.

Design—Retrospective study.

Animals—5 horses.

Procedure—Data collected from the medical records included signalment; history; horse use; degree of lameness; radiographic, ultrasonographic, and scintigraphic findings; treatment; and outcome.

Results—Duration of lameness prior to referral ranged from 14 to 60 days. Mean severity of lameness was grade 3 of 5, and all horses had a single limb affected. All horses had signs of pain during elbow joint manipulation and digital palpation over the lateral aspect of the proximal end of the radius. Radiographic lesions consisted of periosteal proliferation, osteolysis, and subchondral bone lysis. Scintigraphy in 3 horses revealed intense pharmaceutical uptake diffusely involving the proximal end of the radius. Two horses had sepsis of the elbow joint. All horses were treated with antimicrobials long-term; 1 horse was also treated by local perfusion of the radial medullary cavity through an indwelling cannulated screw. At follow-up, all horses had returned to their previous function.

Conclusions and Clinical Relevance—Results suggest that osteomyelitis of the proximal end of the radius can result from a traumatic injury to the antebrachium. Because lesions may be an extension of septic arthritis, a thorough examination of the wound area and elbow joint is recommended. Prolonged systemic antimicrobial treatment can result in a successful outcome. (J Am Vet Med Assoc 2003;223:486–491)

Full access
in Journal of the American Veterinary Medical Association