Search Results

Abstract

Objective—To determine corneal thickness, intraocular pressure (IOP), and horizontal and vertical corneal diameter (HCD and VCD) and to obtain axial measurements of the anterior chamber depth (ACD), crystalline lens thickness (CLT), vitreous chamber depth (VtCD), and axial globe length (AGL) in eyes of Miniature Horses.

Animals—41 healthy Miniature Horses.

Procedure—Ocular component measurements were obtained via ultrasonic pachymetry, applanation tonometry, ultrasound, and by use of a Jameson caliper.

Results—Mean IOP and corneal thickness for all eyes were 26.0 mm Hg and 785.6 µm, respectively. There was no correlation of age with IOP or corneal thickness and no difference in these variables between right and left eyes or between females and males. Mean HCD and VCD were 25.8 and 19.4 mm, respectively; although there were no differences between sexes or between right and left eyes, there was positive correlation of optical corneal diameters with increasing age. Mean ACD, CLT, VtCD, and AGL were smaller in Miniature Horses (5.6, 10.0, 18.1, and 33.7 mm, respectively), compared with values for full-sized horses; there was no difference in these variables between sexes or between right and left eyes in Miniature Horses, but they were correlated with increasing age.

Conclusions and Clinical Relevance—In Miniature Horses, corneal thickness and IOP are similar to values reported for full-sized horses and do not increase with advancing age. Vertical corneal diameter, HCD, and AGL increase until 5, 7, and 2 years of age, respectively. (Am J Vet Res 2003;64:661–665).

Abstract

Objective—To evaluate effectiveness of a combination of topically applied tacrolimus, orally administered prednisone, and a novel-protein diet for treatment of perianal sinuses in dogs and to monitor clinical progress and owner management of the condition for 2 years.

Design—Noncontrolled clinical trial.

Animals—19 dogs with perianal sinuses.

Procedures—Perianal sinuses were diagnosed during physical examination, and dogs were placed on a 16-week treatment protocol consisting of topically applied 0.1% tacrolimus ointment, orally administered prednisone (tapering dose), and a novel-protein diet. Metronidazole was orally administered for the first 2 weeks. Anal sacculectomy was recommended whenever anal sacs were involved. Dogs were evaluated every month for the first 4 months and then every 6 to 12 weeks for 2 years.

Results—Perianal sinuses resolved completely in 15 of 19 dogs during the 16 weeks. In the remaining 4 dogs, the lesions markedly improved but failed to completely resolve. Three of these had anal sac involvement, and the owner of 1 dog had complied poorly with treatment instructions. During the 2 years following treatment, all dogs were maintained on intermittently applied tacrolimus ointment, 4 dogs also received prednisone every other day, and 11 dogs remained on the novel-protein diet. At the conclusion of the study, 13 of the 15 dogs that survived to that point were free of perianal disease.

Conclusions and Clinical Relevance—The described protocol was effective and economical for resolving perianal sinuses. Dogs maintained on intermittent medications were unlikely to redevelop lesions. When the anal sacs were involved, anal sacculectomy appeared to improve the outcome.

Abstract

Objective—To evaluate effects of anesthesia, surgery, and intravenous administration of fluids on plasma concentrations of antidiuretic hormone (ADH), concentration of total solids (TS), PCV, arterial blood pressure (BP), plasma osmolality, and urine output in healthy dogs.

Animals—22 healthy Beagles.

Procedure—11 dogs did not receive fluids, and 11 received 20 ml of lactated Ringer's solution/kg of body weight/h. Plasma ADH adn TS concentrations, PCV, osmolality, and arterial BP were measured before anesthesia (T₀) and after administration of preanesthetic agents (T₁), induction of anesthesia (T₂), and 1 and 2 hours of surgery (T₃ and T₄, respectively). Urine output was measured at T₃ and T₄.

Results—ADH concentrations increased at T₁, T₃, and T₄, compared with concentrations at T₀. Concentration of TS and PCV decreased at all times after administration of preanesthetic drugs. Plasma ADH concentration was less at T₃ in dogs that received fluids, compared with those that did not. Blood pressure did not differ between groups, and osmolality did not increase > 1% from T₀ value at any time. At T₄, rate of urine production was less in dogs that did not receive fluids, compared with those that did.

Conclusions and Clinical Relevance—Plasma ADH concentration increased and PCV and TS concentration decreased in response to anesthesia and surgery. Intravenous administration of fluids resulted in increased urine output but had no effect on ADH concentration or arterial BP. The causes and effects of increased plasma ADH concentrations may affect efficacious administration of fluids during the perioperative period in dogs. (Am J Vet Res 2000;61: 1273–1276)

Abstract

Objective—To quantify and compare intracellular magnesium concentrations (Mg_i) in clinically normal dogs (control dogs) and dogs that have gastric dilatation- volvulus (GDV dogs) and to determine whether there is a difference in Mg_i and serum magnesium concentrations (Mg_s) between GDV dogs with and without cardiac arrhythmias.

Animals—41 control dogs and 21 GDV dogs.

Procedure—Rectus abdominis muscle specimens were obtained from control and GDV dogs for determination of Mg_i. Blood samples were obtained from GDV dogs for determination of Mg_s, and dogs were monitored for 48 hours for cardiac arrhythmias. Muscle specimens were frozen at –40 C, oven dried at 95 C, and digested with concentrated nitric acid. Multielemental analyses were performed by simultaneous/ sequential inductively coupled plasma-atomic emission spectroscopy with fixed-cross flow nebulization. The Mg_i was standardized to sulfur content to correct for the amount of fat and fascia in the muscle specimen. Mean (± SEM) values were recorded in parts per million (ppm).

Results—There were no significant differences in Mg_i between control (627 ± 11.1 ppm) and GDV (597 ± 20.5 ppm) dogs, in Mg_i between GDV dogs with (590 ± 34 ppm) and without (584 ± 29 ppm) cardiac arrhythmias, and in Mg_s between GDV dogs with (1.77 ± 0.26 ppm) and without (1.51 ± 0.09 ppm) cardiac arrhythmias. There was no correlation between Mg_s and Mg_i ( R² =0.0001).

Conclusions and Clinical Relevance—Results indicate that Mg depletion is not pathophysiologically important in dogs with GDV and does not play a role in the cardiac arrhythmias detected in these patients. (Am J Vet Res 2000;61:1415–1417)

Abstract

OBJECTIVE To identify risk factors for mesenteric volvulus (MV) in military working dogs (MWDs).

DESIGN Retrospective case-control study.

ANIMALS 211 MWDs (54 with and 157 without MV [case and control dogs, respectively]).

PROCEDURES Medical records (cases and controls) and necropsy reports (cases) were reviewed. Signalment, pertinent medical and surgical history, behavior and temperament characteristics, feeding schedules, and training types were recorded. Weather patterns for regions where dogs resided were researched. Data were evaluated statistically to identify potential risk factors for MV.

RESULTS Risk factors significantly associated with MV included German Shepherd Dog breed (OR, 11.5), increasing age (OR, 2.0), and history of prophylactic gastropexy (OR, 65.9), other abdominal surgery (after gastropexy and requiring a separate anesthetic episode; OR, 16.9), and gastrointestinal disease (OR, 5.4). Post hoc analysis of the subset of MWDs that underwent gastropexy suggested that postoperative complications were associated with MV in these dogs but type of gastropexy and surgeon experience level were not.

CONCLUSIONS AND CLINICAL RELEVANCE Data supported earlier findings that German Shepherd Dog breed and history of gastrointestinal disease were risk factors for MV. The MWDs with a history of prophylactic gastropexy or other abdominal surgery were more likely to acquire MV than were those without such history. These findings warrant further study. Despite the association between prophylactic gastropexy and MV, the authors remain supportive of this procedure to help prevent the more common disease of gastric dilatation-volvulus.

Abstract

Objective—To evaluate response of euthyroid cats to administration of recombinant human thyroid-stimulating hormone (rhTSH).

Animals—7 healthy cats.

Procedure—Each cat received each of 5 doses of rhTSH (0, 0.025, 0.050, 0.100, and 0.200 mg), IV, at 1-week intervals. Serum concentration of total thyroxine (TT₄) and free thyroxine (fT₄) was measured immediately before each injection (time 0) and 2, 4, 6, and 8 hours after administration of each dose.

Results—Overall TT₄ response did not differ significantly among cats when administered doses were ≥ 0.025 mg. Serum TT₄ concentrations peaked 6 to 8 hours after administration for all doses ≥ 0.025 mg. For all doses ≥ 0.025 mg, mean ± SEM TT₄ concentration at 0, 6, and 8 hours was 33.9 ± 1.7, 101.8 ± 5.9, and 101.5 ± 5.7 nmol/L, respectively. For all doses ≥ 0.025 mg, mean fT4 concentration at 0, 6, and 8 hours was 38.7 ± 2.9, 104.5 ± 7.6, and 100.4 ± 8.0 pmol/L, respectively. At 8 hours, the fT4 response to 0.025 and 0.050 mg was less than the response to 0.100 and 0.200 mg. Adverse reactions after rhTSH administration were not detected.

Conclusions and Clinical Relevance—The TSH stimulation test can be performed in cats by IV administration of 0.025 to 0.200 mg of rhTSH and measurement of serum TT₄ concentrations at time of injection and 6 or 8 hours later. Clinical validation of the TSH stimulation test would facilitate development of additional tests of thyroid gland function, such as a TSH assay. (Am J Vet Res 2003;64:149–152)

Abstract

Objective—To use noninvasive respiratory inductance plethysmography (RIP) to investigate differences in breathing patterns between horses with and without recurrent airway obstruction (RAO) during the onset of airway obstruction induced through confinement to stables.

Animals—12 horses with no history or clinical signs of respiratory disease (control horses) and 7 RAO-affected horses.

Procedures—The study involved 2 phases. In phase 1, the optimal position of RIP bands for recording pulmonary function was investigated in 12 control horses. In phase 2, 7 RAO-affected and 7 control horses were confined to stables. Respiratory inductance plethysmography bands were applied to horses for 24 h/d to record respiratory rate and total displacement in 4-hour periods for 7 days or until RAO-affected horses developed signs of severe RAO that persisted for 2 consecutive days. Lung function was measured once daily.

Results—In phase 1, thoracic and abdominal cavity displacements were best represented by RIP bands positioned at intercostal spaces 6 and 17, respectively. In phase 2, pulmonary function indicated airway obstruction in the RAO-affected group on the final 2 days of stable confinement. Respiratory rate and total degree of respiratory displacement measured by RIP did not differ between the RAO-affected and control groups, but the SDs of these decreased significantly within 8 hours after stable confinement began in RAO-affected horses. Respiratory inductance plethysmography and pulmonary function findings became highly correlated as severity of disease progressed.

Conclusions and Clinical Relevance—The decrease in the SDs of RIP measurements indicated a lower degree of variability in breathing patterns of RAO-affected horses. This loss of variability may provide an early indicator of airway inflammation.

Abstract

Objective—To determine density of corneal endothelial cells and corneal thickness in eyes of euthanatized horses.

Sample Population—52 normal eyes from 26 horses.

Procedure—Eyes were enucleated after horses were euthanatized. Eyes were examined to determine that they did not have visible ocular defects. Noncontact specular microscopy was used to determine density of corneal endothelial cells. Corneal thickness was measured, using ultrasonic pachymetry or specular microscopy.

Results—Mean density of corneal endothelial cells was 3,155 cells/mm². Cell density decreased with age, but sex did not affect cell density. Values did not differ significantly between right and left eyes from the same horse. Cell density of the ventral quadrant was significantly less than cell density of the medial and temporal quadrants. Mean corneal thickness was 893 µm. Sex or age did not affect corneal thickness. Dorsal and ventral quadrants were significantly thicker than the medial and temporal quadrants and central portion of the cornea. We did not detect a correlation between corneal thickness and density of endothelial cells in normal eyes of horses.

Conclusion and Clinical Relevance—Density of corneal endothelial cells decreases with age, but corneal thickness is not affected by age or sex in normal eyes of horses. The technique described here may be useful for determining density of endothelial cells in the cornea of enucleated eyes. This is clinically relevant for analyzing corneal donor tissue prior to harvest and use for corneal transplantation. (Am J Vet Res 2001;62:(479–482)

Abstract

Objective—To evaluate signs of postoperative pain and complications after forelimb onychectomy in cats receiving buprenorphine alone or with bupivacaine administered as a 4-point regional nerve block.

Design—Prospective, randomized, double-blind clinical trial.

Animals—20 cats.

Procedure—All cats received buprenorphine (0.01 mg/kg [0.004 mg/lb], IM) preoperatively. One forelimb of each cat also received bupivacaine (1 mg/kg [0.45 mg/lb] of a 0.75% solution) administered as a 4-point regional nerve block. After onychectomy, discomfort (lameness, foot reaction, and pain) scores were evaluated by 2 experienced observers 2, 4, 6, 8, 24, and 168 hours postoperatively. Complication (hemorrhage, swelling, and infection) scores were evaluated 24 and 168 hours postoperatively. Surgeries were performed by 1 experienced veterinary surgeon. Rescue analgesia was provided if needed.

Results—6 cats required rescue analgesia postoperatively. There was no difference in discomfort or complication scores between control limbs and limbs in which a nerve block was administered. Additionally, there was no difference in discomfort and complication scores between cats that did or did not require rescue analgesia.

Conclusions and Clinical Relevance—Bupivacaine administered as a 4-point regional nerve block in addition to a systemic analgesic did not decrease discomfort or complication scores in cats undergoing forelimb onychectomy.

Abstract

Objective—To describe the abnormal gait of dogs with hip dysplasia by use of kinematic gait analysis.

Animals—19 large-breed dogs with moderate to severe clinical and radiographic evidence of hip dysplasia and 10 clinically normal dogs (controls).

Procedure—Kinematic and force plate data were collected, and degree of coxofemoral joint abductionadduction, mediolateral foot movement, distance between hind feet, maximum hind foot elevation, mediolateral pelvic movement, and coxofemoral joint angular acceleration were calculated. Essential Fourier coefficients were determined and used to reconstruct mean angular acceleration curves. Fourier coefficients and foot and pelvic movement data were compared between groups.

Results—Dogs with hip dysplasia had a greater degree of coxofemoral joint adduction and range of abduction-adduction and greater lateral pelvic movement, compared with controls. Foot movement variables did not differ significantly between groups. Coxofemoral joint angular acceleration was greater in the middle to end of the stance phase, whereas deceleration was greater in the late stance to early swing phase and middle to end of the swing phase in dogs with hip dysplasia, compared with controls.

Conclusions and Clinical Relevance—Differences in degree of coxofemoral joint abduction-adduction, amount of mediolateral pelvic movement, and coxofemoral joint angular acceleration between clinically normal dogs and dogs with hip dysplasia may indicate a compensation in gait of affected dogs as a result of discomfort or biomechanical effects attributable to hip dysplasia and degenerative joint disease. Information gained from kinematic and kinetic gait analyses may be useful in evaluating treatments for hip dysplasia in dogs. (Am J Vet Res 2000;61:974–978)