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Abstract

Objective—To determine whether ticlopidine exerts an antiplatelet effect, estimate the pharmacodynamics of ticlopidine, and evaluate any acute adverse effects associated with administration of ticlopidine in cats.

Animals—8 domestic purpose-bred sexually intact male cats.

Procedure—Ticlopidine was administered orally (50 mg, q 24 h; 100 mg, q 24 h; 200 mg, q 24 h; and 250 mg, q 12 h). Each treatment period consisted of 10 days of drug administration. Platelet aggregation studies with adenosine diphosphate (ADP) and collagen and evaluation of oral mucosal bleeding times (OMBTs) were performed on days 3, 7, and 10 during each drug administration. Serotonin was measured to evaluate secretion at baseline and on day 10 for cats that received the 250-mg dosage.

Results—A significant reduction in platelet aggregation was detected in response to ADP on days 7 and 10 at 100 mg, on day 3 at 200 mg, and on days 3, 7, and 10 at 250 mg. A significant increase in the OMBT and decrease in serotonin release on day 10 at 250 mg was also detected; however, the cats had anorexia and vomiting at the 250-mg dosage.

Conclusions and Clinical Relevance—Although there was a consistent antiplatelet effect at the 250-mg dosage, there was dose-dependent anorexia and vomiting that we conclude precludes the clinical usefulness of this drug in cats. ( Am J Vet Res 2004;65:327–332)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To document ocular findings in cats with blastomycosis.

ANIMALS

35 cats with blastomycosis.

PROCEDURES

Medical records from 1978 through 2019 were reviewed to identify cats with confirmed Blastomyces infection. Cats were grouped as having or not having ocular involvement. Clinical signs, histopathologic findings, and response to treatment were evaluated.

RESULTS

21 of the 35 (60%) cats with confirmed blastomycosis had ocular abnormalities. Two of 21 cats with ocular abnormalities also had systemic hypertension and were excluded. Of the remaining 19 cats, 15 (79%) had bilateral ocular signs. Ten (53%) cats had inflammatory ocular lesions, and 9 (47%) had neuro-ophthalmic abnormalities. Six of the 19 (32%) cats appeared to be completely blind, and 5 (26%) appeared to be unilaterally blind. For the 10 cats with inflammatory ocular lesions, the most common lesions were anterior uveitis (9/20 eyes), active chorioretinitis (6/20 eyes), and retinal detachment (4/20 eyes). For the 9 cats with neuro-ophthalmic abnormalities, the most common abnormalities were a negative menace or tracking response (10/18 eyes) and negative pupillary light response (4/18 eyes).

CLINICAL RELEVANCE

Results suggested that ocular involvement is common in cats with blastomycosis and that both inflammatory lesions and neuro-ophthalmic abnormalities can be seen. Blastomycosis should be considered in the differential diagnosis for cats with anterior uveitis, posterior segment inflammation, or neuro-ophthalmic abnormalities, and a complete ophthalmic examination should be performed in all cats with confirmed or suspected blastomycosis.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify apoptosis in equine intestines and determine whether apoptosis is associated with gastrointestinal tract disease or a specific tissue layer of intestine.

Animals—38 horses that underwent surgery or were euthanatized for small or large intestine obstruction, strangulation, or distension and 9 control horses euthanatized for reasons other than gastrointestinal tract disease or systemic disease.

Procedure—Specimens were collected at surgery from intestine involved in the primary lesion and distant to the primary lesion site or at necropsy from several sites including the primary lesion site. Histologic tissue sections were stained with H&E, and apoptosis was detected by use of the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique. The number of apoptotic cells per hpf was counted in the mucosa, circular muscle, longitudinal muscle, and serosa.

Results—Apoptotic nuclei were seen in all layers of intestine. An increased number of apoptotic cells was found in the circular muscle of the intestine from horses with simple obstruction, compared with strangulating obstruction or healthy intestine. Intestine distant from a primary strangulating lesion had higher numbers of apoptotic cells than did intestine distant from a simple obstructive lesion or intestine taken at the site of a strangulating or simple obstructive lesion.

Conclusions and Clinical Relevance—Intestine from horses with obstructing or strangulating lesions in the small intestine and large colon had high numbers of apoptotic cells possibly because of ischemic cell injury and subsequent inflammation. Whether substantial apoptosis affects intestinal function is not yet known. (Am J Vet Res 2003;64:982–988)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess changes in systemic hydration, concentrations of electrolytes in plasma, hydration of colonic contents and feces, and gastrointestinal transit in horses treated with IV fluid therapy or enteral administration of magnesium sulfate (MgSO4), sodium sulfate (NaSO4), water, or a balanced electrolyte solution.

Animals—7 horses with fistulas in the right dorsal colon (RDC).

Procedure—In a crossover design, horses alternately received 1 of 6 treatments: no treatment (control); IV fluid therapy with lactated Ringer's solution; or enteral administration of MgSO4, Na2SO4, water, or a balanced electrolyte solution via nasogastric intubation. Physical examinations were performed and samples of blood, RDC contents, and feces were collected every 6 hours during the 48 hour-observation period. Horses were muzzled for the initial 24 hours but had access to water ad libitum. Horses had access to hay, salt, and water ad libitum for the last 24 hours.

Results—Enteral administration of a balanced electrolyte solution and Na2SO4 were the best treatments for promoting hydration of RDC contents, followed by water. Sodium sulfate was the best treatment for promoting fecal hydration, followed by MgSO4 and the balanced electrolyte solution. Sodium sulfate caused hypocalcemia and hypernatremia, and water caused hyponatremia.

Conclusions and Clinical Relevance—Enteral administration of a balanced electrolyte solution promoted hydration of RDC contents and may be useful in horses with large colon impactions. Enteral administration of either Na2SO4 or water may promote hydration of RDC contents but can cause severe electrolyte imbalances. (Am J Vet Res 2004;65:695–704)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess changes in systemic hydration, concentrations of plasma electrolytes, hydration and physical properties of colonic contents and feces, and gastrointestinal transit in horses with access to large amounts of grain.

Animals—6 horses with right dorsal colon (RDC) fistulas.

Procedure—In a crossover design, horses were alternately fed 1 of 3 diets: orchard grass hay ad libitum after being adapted to this diet for at least 5 days, orchard grass hay ad libitum and 4.55 kg of grain offered every 12 hours after being adapted to orchard grass hay ad libitum for at least 5 days, or orchard grass hay ad libitum and 4.55 kg of grain offered every 12 hours after being adapted to this diet for at least 5 days. Physical examinations were performed and samples of blood, colonic contents, and feces were collected every 6 hours during a 48-hour observation period.

Results—Grain ingestion had several effects, including changes in the concentrations of electrolytes in plasma; RDC contents became more homogenous, dehydrated, foamy, and less dense; RDC contents flowed spontaneously when the cannula was opened; RDC contents expanded when heated in an oven; and feces became fetid and less formed. Horses did not have any clinical signs of colic, endotoxemia, or laminitis.

Conclusions and Clinical Relevance—Changes observed in the colonic contents and feces may be explained by the large amounts of hydrolyzable carbohydrates provided by grain. Access to large amounts of grain may increase the risk of tympany and displacement of the large intestine. ( Am J Vet Res 2004;65:687–694)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine effects of cyclophotocoagulation via administration of 100 J with a neodymium: yttrium aluminum garnet (Nd:YAG) laser on corneal touch threshold (CTT), intraocular pressure (IOP), aqueous tear production, and corneal nerve morphology in eyes of dogs.

Animals—15 dogs.

Procedure—Noncontact Nd:YAG laser was transsclerally applied (10 applications; 25 W for 0.1 seconds for each application to each of 4 quadrants) to the ciliary body of the left eye of 15 dogs; the right eye was the control eye. Corneal integrity, CTT, tear production as measured by the Schirmer tear test (STT), and IOP were evaluated for 14 days following laser treatment. On day 14, dogs were euthanatized, eyes harvested, and corneas stained with gold chloride. Major nerve bundles were analyzed by use of a drawing tube attached to a light microscope, and maximum diameters were measured by use of image analysis software.

Results—All laser-treated eyes had significantly higher CTT values, compared with control eyes. Six of 15 laser-treated eyes developed ulcerative keratitis. On most days, IOP was significantly lower in laser-treated eyes in both morning and evening. Laser-treated eyes had a significant decrease of approximately 1 nerve bundle/corneal quadrant. Values for STT or nerve bundle diameters did not differ significantly.

Conclusion and Clinical Relevance—Administration of 100 J with a Nd:YAG laser effectively reduced IOP while increasing CTT and caused a significant decrease in number, but not diameter, of major corneal nerve bundles. Nerve damage and corneal hypoesthesia are etiologic factors in ulcerative keratitis following Nd:YAG cyclophotocoagulation. (Am J Vet Res 2002;63:906–915)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To describe the anatomic features of the pituitary gland region in horses via computed tomography (CT) and determine the accuracy of CT for estimating normal equine pituitary gland dimensions.

Animals—25 adult horses with no clinical signs of pituitary disease.

Procedure—Transverse CT images and gross transverse tissue sections were compared in 2 horses. Contrast-enhanced CT of the pituitary gland region was performed postmortem in 23 horses with 4 slice thickness and interval settings (10-mm contiguous or overlapping slices and 4-mm contiguous or overlapping slices). Gross and CT estimates of pituitary gland dimensions were compared via ANOVA. Accuracy of CT estimates was calculated with gross pituitary gland measurements as the known value.

Results—Pituitary glands were located between the temporomandibular joints and had contrast enhancement. Mean gross dimensions were length, 2.11 cm; width, 2.16 cm; height, 0.98 cm; and volume, 2.66 cm3. Gross measurements and CT estimates of pituitary gland length from 10-mm contiguous and overlapping slices did not differ. Gross measurements and CT estimates of pituitary gland width from 4-mm contiguous and overlapping slices did not differ. Estimates of height and volume from all CT techniques differed from gross measurements. Accuracies for CT estimates were length, 88 to 99%; width, 81 to 92%; height, 58 to 71%; and volume, 43 to 55%.

Conclusions and Clinical Relevance—Accuracy of estimates of pituitary gland dimension in horses varied with CT scanning technique; via CT, estimates of length and width of glands were more accurate than estimates of height or volume. (Am J Vet Res 2003;64:1387–1394)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effect of frequent milkout (FMO) on the outcome of experimentally induced Escherichia coli mastitis in cows.

Design—Randomized complete block study.

Animals—16 Holstein dairy cows.

Procedure—Cows were randomly assigned to 1 of 4 groups and were either not infected and not treated (NI-NT), experimentally infected with E coli and not treated (EC-NT), not infected and FMO (NI-FMO), or experimentally infected with E coli and FMO (EC-FMO). The infected quarter in cows in FMO groups was milked out every 4 hours from 16 to 36 hours and every 6 hours from 36 to 84 hours after challenge, with the aid of oxytocin administration. Somatic cell counts (SCC); times to bacterial, clinical, and systemic cures; and serum concentrations of α-lactalbumin were determined.

Results—Use of FMO did not appear to affect SCC. For EC-NT and EC-FMO groups, mean bacterial cure times were 203 and 159 hours, clinical cure times were 276 and 360 hours, and systemic cure times were 144 and 159 hours, respectively; these times were not significantly different. Concentrations of α-lactalbumin were significantly increased in the EC-NT group at 12 hours and in the NI-FMO group at 36 and 60 hours after challenge, compared with values of cows in other treatment groups.

Conclusions and Clinical Relevance—Compared with results in control cows, FMO does not appear to be an efficacious treatment for experimentally induced moderate to severe E coli mastitis. (J Am Vet Med Assoc 2003;222:63–66)

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare induction and recovery characteristics and cardiopulmonary effects of isoflurane and sevoflurane in bald eagles.

Animals—17 healthy adult bald eagles.

Procedures—Anesthesia was induced with isoflurane or sevoflurane delivered in oxygen via a facemask in a crossover design with 4 weeks between treatments. Eagles were intubated, allowed to breathe spontaneously, and instrumented for cardiopulmonary measurements. Time to induction, extubation, and recovery, as well as smoothness of recovery, were recorded.

Results—Administration of sevoflurane resulted in a significantly quicker recovery, compared with isoflurane. Temperature, heart rate, and respiratory rate significantly decreased over time, whereas systolic (SAP), diastolic (DAP), and mean arterial blood pressure (MAP) significantly increased over time with each treatment. Temperature, heart rate, SAP, DAP, and MAP were significantly higher with isoflurane. Blood pH significantly decreased, whereas PaCO2 significantly increased over time with each treatment. Bicarbonate and total carbon dioxide concentrations significantly increased over time with each treatment; however, there was a significant time-treatment interaction. The PaO2 and arterial oxygen saturation increased over time with isoflurane and decreased over time with sevoflurane with a significant time-treatment interaction. Six eagles developed cardiac arrhythmias with isoflurane, as did 4 with sevoflurane anesthesia.

Conclusions and Clinical Relevance—Isoflurane and sevoflurane administration resulted in smooth, rapid induction of and recovery from anesthesia similar to other species. Isoflurane administration resulted in tachycardia, hypertension, and more arrhythmias, compared with sevoflurane. Sevoflurane was associated with fewer adverse effects and may be particularly beneficial in compromised bald eagles.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess the potential of adipose-derived nucleated cell (ADNC) fractions to improve tendon repair in horses with collagenase-induced tendinitis.

Animals—8 horses.

Procedures—Collagenase was used to induce tendinitis in the superficial digital flexor tendon of 1 forelimb in each horse. Four horses were treated by injection of autogenous ADNC fractions, and 4 control horses were injected with PBS solution. Healing was compared by weekly ultrasonographic evaluation. Horses were euthanatized at 6 weeks. Gross and histologic evaluation of tendon structure, fiber alignment, and collagen typing were used to define tendon architecture. Biochemical and molecular analyses of collagen, DNA, and proteoglycan and gene expression of collagen type I and type III, decorin, cartilage oligomeric matrix protein (COMP), and insulin-like growth factor-I were performed.

Results—Ultrasonography revealed no difference in rate or quality of repair between groups. Histologic evaluation revealed a significant improvement in tendon fiber architecture; reductions in vascularity, inflammatory cell infiltrate, and collagen type III formation; and improvements in tendon fiber density and alignment in ADNC-treated tendons. Repair sites did not differ in DNA, proteoglycan, or total collagen content. Gene expression of collagen type I and type III in treated and control tendons were similar. Gene expression of COMP was significantly increased in ADNC-injected tendons.

Conclusions and Clinical Relevance—ADNC injection improved tendon organization in treated tendons. Although biochemical and molecular differences were less profound, tendons appeared architecturally improved after ADNC injection, which was corroborated by improved tendon COMP expression. Use of ADNC in horses with tendinitis appears warranted.

Full access
in American Journal of Veterinary Research