OBJECTIVE To determine the effect of repeated gas sterilization on rate of closure of ameroid ring constrictors in vitro. SAMPLE Twenty-four 3.5-mm ameroid ring constrictors. PROCEDURES Ameroid ring constrictors were allocated to 1 of 4 treatment groups (6/group) to undergo gas sterilization 0, 1, 5, or 10 times. After sterilization, constrictors were incubated in canine plasma at a protein concentration of 3 g/dL for 27 days. A digital camera was used to obtain images of the constrictors prior to and at various points during incubation, and lumen diameter was measured. RESULTS Mean ± SD percentage of lumen closure for all groups of ameroid ring constrictors combined was 85.2 ± 1.6% at day 0 (prior to plasma incubation) and 95.4 ± 0.8% at day 27. Mean lumen area was 3.64 ± 0.43 mm2 (95% confidence interval, 2.67 to 4.77 mm2) at day 0 and 1.32 ± 0.25 mm2 (95% confidence interval, 0.76 to 2.04 mm2) at day 27. None of the ameroid ring constrictors had closed completely by day 27. CONCLUSIONS AND CLINICAL RELEVANCE Overall closure rates for ameroid ring constrictors appeared to be unaffected by repeated gas sterilization up to 10 times. Findings suggested that veterinary surgeons can resterilize ameroid ring constrictors up to 10 times with confidence that ring properties would remain suitable for clinical use.

OBJECTIVE To assess and compare results of anterior segment angiography of ophthalmologically normal cats following IV injection with indocyanine green and sodium fluorescein dyes. ANIMALS 10 client-owned cats. PROCEDURES Anterior segment angiography was performed in anesthetized cats following administration of 0.25% indocyanine green (1.0 mg/kg, IV) or 10% sodium fluorescein (20 mg/kg, IV) solution. All cats received both treatments. Imaging (1 eye/cat) was performed with a full-spectrum digital single-lens reflex camera equipped with an adaptor (1 image/s for 30 seconds) immediately following IV dye injection and 1, 2, 3, 4, and 5 minutes after injection. Onset and duration of arterial, capillary, and venous phases of iris vasculature were identified and compared statistically between treatments. Degree of iridal pigmentation, leakage of dye from iris vasculature, and image quality were subjectively assessed. RESULTS No differences were found in onset or duration of vascular phases between treatments. Visibility of the iris vasculature was not impaired by poor or moderate iridal pigmentation with either method. Indocyanine green provided subjectively better vascular detail and image contrast than sodium fluorescein. No vascular dye leakage was observed following indocyanine green administration. Leakage of dye from blood vessels in the stroma (in 10 cats) and presence of dye in the anterior chamber (in 5 cats) were detected after sodium fluorescein administration. CONCLUSIONS AND CLINICAL RELEVANCE Images obtained with either fluorescent dye were considered to be of diagnostic quality. Lack of leakage following indocyanine green administration suggested this treatment may have better diagnostic utility for anterior segment angiography. The photographic equipment used provided a cost-effective alternative to existing imaging systems.

OBJECTIVE To evaluate the effectiveness of a novel fluorescence tracer agent, MB-102, for conducting ocular angiography in dogs. ANIMALS 10 ophthalmologically normal dogs (2 to 4 years old) and 10 dogs with retinal degeneration or primary open-angle glaucoma (< 6 years old). PROCEDURES While anesthetized, all dogs received sodium fluorescein (20 mg/kg, IV) or MB-102 (20 or 40 mg/kg, IV) first and then the other dye in a second treatment session 2 days later in a randomized crossover design. Anterior fluorescence angiography was performed on one eye and posterior fluorescence angiography on the other. Imaging was performed with a full-spectrum camera and camera adaptor system. Filter sets that were tailored to match the excitation and emission characteristics of each angiographic fluorescent agent were used. RESULTS All phases and phase intervals during anterior and posterior segment angiography were identified, regardless of the dye used. However, agent fluorescence and visualization of the iridal blood vessels were hindered in some dogs, irrespective of agent, owing to the degree of iridal pigmentation present. No significant difference was noted between the 2 dyes in any phase or phase interval, and slight improvement in image contrast was observed with MB-102 during the venous phases owing to a reduction of vessel wall staining in both normal and diseased eyes. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that MB-102 would be useful for conducting ocular angiography in dogs.

OBJECTIVE To determine the optimal intercostal space (ICS) for thoracoscopic-assisted pulmonary surgery for lung lobectomy in cats. SAMPLE 8 cat cadavers. PROCEDURES Cadavers were placed in lateral recumbency. A 5-cm minithoracotomy incision was made in the middle third of ICS 4 through 7 on the left side and 4 through 8 on the right side, and a wound retractor device was placed. A camera port was made in the middle third of ICS 9. Each lung lobe was sequentially exteriorized at each respective ICS. A thoracoabdominal stapler was placed to simulate a lung lobectomy, and distance from the stapler anvil to the hilus was measured. RESULTS For the left cranial lung lobe, there was no significant difference in median distance from the stapler anvil to the pulmonary hilus for ICS 4 through 6. Simulated lobectomy of the left caudal lung lobe performed at ICS 5 and 6 resulted in a significantly shorter distance, compared with lobectomy performed at ICS 4 and 7. Simulated lobectomy of the right cranial and right middle lung lobes performed at ICS 4 and 5 resulted in a significantly shorter distance, compared with lobectomy performed at ICS 7. Simulated lobectomy of the accessory and right caudal lung lobes at ICS 5 and 6 resulted in a significantly shorter distance than for lobectomy performed at ICS 8. CONCLUSIONS AND CLINICAL RELEVANCE An optimal ICS for a minithoracotomy incision was determined for thoracoscopic-assisted lung lobectomy in cats.

OBJECTIVE To assess and compare 2 injection techniques for conducting ocular anterior segment indocyanine green angiography (ASICGA) and sodium fluorescein (SF) angiography in horses. ANIMALS 3 healthy adult female horses (age range, 19 to 25 years). PROCEDURES Horses were sedated, jugular catheters were placed, and manual restraint was used to ensure proper positioning for the angiography procedure. Two injection techniques (IV and intra-arterial) were performed for each horse 1 week apart. Intravenous injections of 0.25% indocyanine green (ICG; 50 mg) and 10% SF (10 mg/kg) were administered via the jugular catheter. Intra-arterial injections of ICG (1 mg) and SF (1 mg/kg) were administered into the common carotid artery with ultrasound guidance. Angiography was performed by use of an adaptor system comprised of a modified digital single-lens reflex camera, camera adaptor, and lens. Imaging was performed at a rate of 3 images/s for 60 seconds immediately following ICG injection, then at 2, 3, 4, and 5 minutes after injection. The SF was injected 5 minutes thereafter. RESULTS ASICGA allowed visual identification of the arterial, capillary, and venous phases of angiography. Intra-arterial administration provided superior dye fluorescence, sharper contrast, and faster dye passage than IV administration. Visibility of the iris vasculature was limited with SF, and extravasation of SF was noted. No clinically important adverse events were detected. CONCLUSIONS AND CLINICAL RELEVANCE ASICGA images were obtainable with both injection techniques; however, visibility of the iris vasculature was better with intra-arterial administration of ICG. The ASICGA technique may serve as a viable ocular imaging modality for horses.

Objective—To determine the magnitude and location of skin movement attributable to the cutaneus trunci muscle reflex in response to localized stimulation of the skin of the dorsolateral aspect of the thoracic wall in horses. Animals—8 horses. Procedures—A grid of 56 reflective markers was applied to the lateral aspect of the body wall of each horse; markers were placed at 10-cm intervals in 7 rows and 8 columns. A motion analysis system with 10 infrared cameras was used to track movements of the markers in response to tactile stimulation of the dorsolateral aspect of the thoracic wall at the levels of T6, T11, and T16. Marker movement data determined after skin stimulation were used to create a skin deformation gradient tensor field, which was analyzed with custom software. Results—The sites of maximal skin deformation were located close to the stimulation sites; the centers of the twitch responses were located a mean distance of 7.7 to 12.8 cm ventral and between 6.6 cm cranial and 3.1 cm caudal to the stimulation sites. Conclusions and Clinical Relevance—Findings of this study may have implications for assessment of nerve conduction velocities of the cutaneus trunci muscle reflex and may enhance understanding of the responses of horses to placement of tack or other equipment on skin over the cutaneus trunci muscles.

Objective: To assess joint kinematics in dogs with osteoarthritis of the hip joints during walking up an incline or down a decline and over low obstacles and to compare findings with data for nonlame dogs. Animals: 10 dogs with osteoarthritis of the hip joints (mean ± SD age, 6.95 ± 3.17 years; mean body weight, 34.33 ± 13.58 kg) and 8 nonlame dogs (3.4 ± 2.0 years; 23.6 ± 4.6 kg). Procedures: Reflective markers located on the limbs and high-speed cameras were used to record joint kinematics during walking up an incline or down a decline and over low obstacles. Maximal flexion, extension, and range of motion of the hip joints were calculated. Results: Osteoarthritis of the hip joints reduced extension of both hip joints and flexion of the contralateral hind limb, compared with flexion of the lame hind limb, during walking down a decline. Walking up an incline resulted in decreased extension of the stifle joint in both hind limbs of osteoarthritic dogs; extension was significantly decreased for the lame hind limb. During walking over low obstacles, maximal flexion of the stifle joint was increased significantly for the contralateral hind limb. Maximal flexion was increased in both tarsal joints. Conclusions and Clinical Relevance: Osteoarthritis of the hip joints led to complex changes in the gait of dogs, which involved more joints than the affected hip joint alone. Each exercise had specific effects on joint kinematics that must be considered when planning a rehabilitation program.

OBJECTIVE To compare the degree of white line separation created by increasing physiologic loads between bovine claws with and without toe-tip necrosis (TTN). SAMPLE Cadaveric bovine hind limbs with (n = 10) and without (10) TTN. PROCEDURES Hind limbs in which 1 or both claws had evidence of apical white line separation were considered to have TTN. Hind limbs in which neither claw had evidence of white line separation were considered controls. Each hind limb was mounted in a materials testing system with the bottom surface of the hoof angled at approximately 5° to the horizontal plane such that the apex of the claws made initial contact with the clear testing surface to simulate physiologic loading conditions. A digital camera mounted underneath the testing surface was used to obtain images of the bottom of the hoof during the application of each of 3 increasing static loads (1, 2, and 3 kN). The images were analyzed with commercial image-processing software to quantify white line separation area. RESULTS White line separation area was significantly greater for claws with TTN than for control claws and increased as the applied load increased. White line separation was almost nonexistent in control claws and was not affected by increasing load. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that mechanical loading exacerbated TTN, but compressive loading alone, even at excessive levels, did not initiate the condition. Interventions (eg, hoof blocks) that decrease loading of affected claws may be beneficial for the treatment of TTN at its earliest stages.

OBJECTIVE To evaluate 2 methods of surveying free-roaming cats (Felis catus) and identify factors potentially associated with the presence of such cats in a mixed-urban environment. ANIMALS Free-roaming cats on and near The Ohio State University campus. PROCEDURES The university campus and surrounding areas were divided into zones classified by land-use category; 100 zones were selected for surveillance of free-roaming cats by the line-transect method (with visual observation). Twenty-three of the 100 zones were selected for surveillance by the trail-camera method (motion-triggered still photography). Food resources in the study site were mapped, and the presence of other animal species was recorded with trail cameras. Potential associations between the number of cat sightings and variables of interest were assessed by statistical methods, RESULTS There were 6 cat sightings in 5 zones and 92 cat sightings in 9 zones with the line-transect and trail-camera methods, respectively. Cats were most frequently detected off campus and in urban land-use zones. The number of cat sightings with trail cameras was significantly correlated with the density of food resources but not wildlife sightings in the area and was significantly greater at night than during the day. CONCLUSIONS AND CLINICAL RELEVANCE The number of sightings with the trail-camera method was substantially higher than that obtained with the line-transect method; however, identification of individual cats was generally not possible, and population size could not be estimated with these methods. Communities considering population control for free-roaming cats should consider the use of trail cameras to identify areas with high free-roaming cat activity and observation at night to gather baseline data. Easily accessible food waste may attract free-roaming cats.