OBJECTIVE To compare the efficacy of various concentrations and combinations of serum, EDTA, 3 tetracyclines, and N-acetylcysteine (NAC) for collagenase inhibition in an in vitro corneal degradation model.
SAMPLE Grossly normal corneas from recently euthanized dogs and horses and fresh serum from healthy dogs and horses.
PROCEDURES Serum was pooled by species for in vitro use. For each species, sections of cornea were dried, weighed, and incubated with clostridial collagenase (800 U/mL) in 5 mL of a 5mM calcium chloride-saline (0.9% NaCl) incubation solution and 500 μL of 1 of 19 treatments (homologous serum; 0.3%, 1.0%, or 2% EDTA; 0.1%, 0.5%, or 1.0% tetracycline, doxycycline, or minocycline; 0.5%, 1.0%, or 5.0% NAC; serum with 0.5% tetracycline; serum with 1.0% EDTA; or 1.0% EDTA with 0.5% tetracycline). Positive and negative control specimens were incubated with 5 mL of incubation solution with and without collagenase, respectively. Each control and treatment was replicated 4 times for each species. Following incubation, corneal specimens were dried and reweighed. The percentage corneal degradation was calculated and compared among treatments within each species.
RESULTS Treatments with tetracyclines at concentrations ≥ 0.5%, with EDTA at concentrations ≥ 0.3%, and with NAC at concentrations ≥ 0.5% were more effective at preventing corneal degradation than serum in both species. The efficacy of each combination treatment was equal to or less than that of its components.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested EDTA, tetracyclines, and NAC may be beneficial for topical treatment of keratomalacia, but in vivo studies are required.
Objective—To determine whether differences exist in the calculated intraocular lens (IOL) strengths of a population of adult horses and to assess the association between calculated IOL strength and horse height, body weight, and age, and between calculated IOL strength and corneal diameter.
Animals—28 clinically normal adult horses (56 eyes).
Procedures—Axial globe lengths and anterior chamber depths were measured ultrasonographically. Corneal curvatures were determined with a modified photokeratometer and brightness-mode ultrasonographic images. Data were used in the Binkhorst equation to calculate the predicted IOL strength for each eye. The calculated IOL strengths were compared with a repeated-measures ANOVA. Corneal curvature values (photokeratometer vs brightness-mode ultrasonographic images) were compared with a paired t test. Coefficients of determination were used to measure associations.
Results—Calculated IOL strengths (range, 15.4 to 30.1 diopters) differed significantly among horses. There was a significant difference in the corneal curvatures as determined via the 2 methods. Weak associations were found between calculated IOL strength and horse height and between calculated IOL strength and vertical corneal diameter.
Conclusions and Clinical Relevance—Calculated IOL strength differed significantly among horses. Because only weak associations were detected between calculated IOL strength and horse height and vertical corneal diameter, these factors would not serve as reliable indicators for selection of the IOL strength for a specific horse.
Objective—To determine whether joint lavage performed simultaneously with IV regional limb perfusion (IVRLP) reduces the effectiveness of IVRLP and to compare 2 types of tourniquets used for this procedure in horses.
Animals—11 adult horses.
Procedures—2 groups of 6 horses were tested by use of a pneumatic or an Esmarch tourniquet (1 horse was tested twice [once in each group]). Standing IVRLP with amikacin (500 mg) was performed for 30 minutes. Simultaneously, the metacarpophalangeal joint was lavaged with 2 L of lactated Ringer's solution and the egress fluids were collected. Samples of the distal interphalangeal joint synovial fluid and blood from the digital and jugular veins were collected at set time intervals. Amikacin concentrations in all fluids were determined via fluorescence polarization immunoassay.
Results—Less amikacin was measured in the systemic circulation with the Esmarch tourniquet than with the pneumatic tourniquet. Amikacin concentrations in the synovial fluid from the distal interphalangeal joints of the Esmarch tourniquet group ranged from 45.1 to 1,968 μg/mL and in the pneumatic tourniquet group ranged from 1.7 to 92.3 μg/mL after 30 minutes of IVRLP. Total loss of amikacin in the egress fluids from the joint lavage ranged from < 1.36 to 7.72 mg for the Esmarch tourniquet group and from < 1.20 to 1.75 mg for the pneumatic tourniquet group.
Conclusions and Clinical Relevance—On standing horses, IVRLP performed simultaneously with joint lavage resulted in negligible loss of amikacin in the egress lavage fluids. The Esmarch tourniquet was more effective in preventing loss of amikacin from the distal portion of the limb, easier to use, and less expensive than the pneumatic tourniquet.
Objective—To evaluate the effect of multiple hydrogen peroxide gas plasma (HPGP) sterilizations on the rate of closure of ameroid constrictors.
Sample—Thirty-six 5.0-mm ameroid constrictors.
Procedures—Ameroid constrictors were randomly allocated to 6 groups. Each group underwent 1, 2, 3, 4, 5, or 6 HPGP sterilizations. Ameroid constrictors were then incubated for 35 days in canine plasma and digitally imaged at predetermined times during incubation. One individual, who was unaware of the group to which each ameroid constrictor was assigned, measured the lumen area of the constrictor on each digital image. Mean lumen area was compared among groups.
Results—No ameroid constrictors were completely closed after 35 days of incubation in canine plasma. Mean lumen area after incubation did not differ among constrictors that underwent 1, 2, and 3 sterilizations. Constrictors that underwent 4 sterilizations were closed significantly more than were those that underwent 1, 2, or 3 sterilizations. Mean lumen area after incubation did not differ significantly between constrictors that underwent 5 and 6 sterilizations, although the final lumen areas for those constrictors were significantly smaller than those for constrictors that underwent 1, 2, 3, and 4 sterilizations.
Conclusions and Clinical Relevance—Ameroid constrictors that underwent 5 and 6 HPGP sterilizations had a 9% to 12% decrease in lumen area, compared with that of constrictors that underwent ≤ 4 plasma sterilizations, and the use of such constrictors could increase the risk of portal hypertension and secondary acquired shunting or decrease the risk of persistent shunting.
Objective—To calculate the monthly incidence of
gastric dilatation-volvulus (GDV) in a population of military
working dogs during a 5-year period and determine
whether there was an association with synoptic
Sample Population—Medical records of all military
working dogs housed at Lackland Air Force Base,Tex,
from Jan 1, 1993 to Dec 31, 1997.
Procedure—Confirmed cases of GDV were identified
from evaluation of medical records and used to calculate
incidence of GDV. Factor analysis of local climatologic
data was used to classify each day into 1 of 8
meteorologically homogeneous types of days for this
location. Occurrence of GDV was compared with frequency
of occurrence of synoptic climatologic days.
Results—48 cases of GDV were identified from
January 1993 through December 1997. Mean monthly
incidence was 2.5 cases/1,000 dogs at risk (range,
0 to 18.5 cases/1,000 dogs; median, 2.5 cases/1,000
dogs). A seasonal increase in incidence of GDV was
detected, because half of the episodes were during
November, December, and January. An association
with a specific synoptic climatologic day was not
Conclusion and Clinical Relevance—Seasonal fluctuations
in incidence of GDV may be associated with
external factors that precipitate physiologic changes
resulting in GDV. Although a specific cause-effect relationship
was not documented, clinicians must be alert
for the potential of seasonal variation in incidence of
GDV and accordingly heighten their index of suspicion
for the condition, particularly in populations of dogs
that are predisposed to development of GDV. (Am J
Vet Res 2002;63:47–52)
To determine the effects of 2-, 4-, 6- and 8-strand suture repairs on the biomechanical properties of canine gastrocnemius tenorrhaphy constructs in an ex vivo model.
56 cadaveric gastrocnemius musculotendinous units from 28 adult large-breed dogs.
Tendons were randomly assigned to 4 repair groups (2-, 4-, 6- or 8-strand suture technique; n = 14/group). Following tenotomy, repairs were performed with the assigned number of strands of 2-0 polypropylene suture in a simple interrupted pattern. Biomechanical testing was performed. Yield, peak, and failure loads, the incidence of 1- and 3-mm gap formation, forces associated with gap formation, and failure modes were compared among groups.
Yield, peak, and failure forces differed significantly among groups, with significantly greater force required as the number of suture strands used for tendon repair increased. The force required to create a 1- or 3-mm gap between tendon ends also differed among groups and increased significantly with number of strands used. All constructs failed by mode of suture pull-through.
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated that increasing the number of suture strands crossing the repair site significantly increases the tensile strength of canine gastrocnemius tendon repair constructs and their resistance to gap formation. Future studies are needed to assess the effects of multistrand suture patterns on tendon glide function, blood supply, healing, and long-term clinical function in dogs to inform clinical decision-making.
To evaluate the effect of presurgical storage conditions on leakage pressures of enterotomy sites closed with unidirectional barbed suture material in fresh, chilled, and frozen-thawed cadaveric canine jejunal specimens.
36 grossly normal jejunal segments obtained from 4 dog cadavers.
9 jejunal segments were harvested immediately from each euthanized dog and randomly assigned to be tested within 4 hours after collection (fresh segments), stored at 4°C for 24 hours before testing (chilled segments), or stored at −20°C for 7 days and thawed at 21°C for 6 hours before testing (frozen-thawed segments). For leakage pressure testing, a 3-cm-long antimesenteric enterotomy was performed and repaired with 3-0 unidirectional barbed suture material in a simple continuous pattern in each segment. Time to complete the enterotomy, initial leakage pressure, maximum intraluminal pressure, and leakage location were recorded for each segment.
Mean ± SD initial leakage pressure for fresh, chilled, and frozen-thawed segments was 52.8 ± 14.9 mm Hg, 51.8 ± 11.9 mm Hg, and 33.3 ± 7.7 mm Hg, respectively. Frozen-thawed segments had significantly lower mean initial leakage pressure, compared with findings for fresh or chilled segments. Time to complete the enterotomy, maximum intraluminal pressure, and leakage location did not differ among groups.
CONCLUSIONS AND CLINICAL RELEVANCE
Leak pressure testing of cadaveric jejunal segments that are fresh or chilled at 4°C for 24 hours is recommended for enterotomy studies involving barbed suture material in dogs. Freezing and thawing of cadaveric jejunal tissues prior to investigative use is not recommended because leak pressure data may be falsely low.
OBJECTIVE To evaluate the effect of a bovine albumin–derivatized glutaraldehyde (BA-DG) biopolymer sealant on leakage pressures of intestinal anastomoses in jejunal tissue collected from fresh canine cadavers and to evaluate changes in circumference and cross-sectional area of the anastomotic site resulting from sealant application.
SAMPLE 24 jejunal anastomoses from 4 fresh canine cadavers.
PROCEDURES Jejunal tissue specimens were collected, and adjacent segment anastomoses were created within 12 hours after euthanasia of each dog. The tissue constructs were randomly assigned to 1 of 2 groups in which sealant was or was not applied. The outer circumference of all anastomoses in the sealant group was measured before and after application of the sealant; the cross-sectional area at the anastomotic site was then calculated at each time point. Tissue constructs were pressure tested, and leakage pressure and site were recorded. All testing was completed within 24 hours after tissue collection.
RESULTS Compared with preapplication findings, there were no significant changes in outer circumference or cross-sectional area at the anastomotic site after sealant application. Leakage pressures in the sealant group were significantly higher than those in the no-sealant group.
CONCLUSIONS AND CLINICAL RELEVANCE The use of surgical sealant on fresh canine cadaver jejunal anastomoses resulted in significantly higher leakage pressure at the anastomotic site; no immediate tissue deformation of the outer circumference or cross-sectional area occurred after sealant application. Future in vivo investigations are warranted to evaluate the effects of this sealant and potential benefits for clinical patients undergoing enterectomy.
Objective—To determine whether urine protein-to-creatinine (UP:C) ratio assessment provides an estimate of urine protein excretion (UPE) over a 24-hour period in horses and ponies, establish a preliminary UP:C ratio reference range, and determine UP:C ratio variation over time in healthy equids.
Animals—11 female horses and 6 female ponies.
Procedures—Urine was collected from all equids at 4-hour intervals for 24 hours. Total 24-hour UPE (mg of protein/kg of body weight) and UP:C ratio were determined; these variables were also assessed in aliquots of urine collected at 4-hour intervals. On 2 additional days, urine samples were also obtained from 6 horses (1 sample/horse/d) to determine day-to-day variation in UP:C ratio. Correlation between 4-hour or 24-hour UPE and UP:C ratio values was assessed. Reference ranges for 24-hour UPE, 24-hour UP:C ratio, and 4-hour UP:C ratios were calculated as central 95th percentiles of observed values.
Results—Mean 24-hour UPE (4.28 ± 2.99 mg/kg) and 24-hour UP:C ratio (0.0 to 0.37) had excellent correlation (R = 0.826; P < 0.001) in both horses and ponies; analysis of 4-hour data also revealed good correlation (R = 0.782; P < 0.001) with these variables. Calculated UPE and UP:C ratio reference ranges were similar to established ranges in other species. Day-to-day variability in UP:C ratio was minimal, and all results were within the reference range calculated by use of the 24-hour urine samples.
Conclusions and Clinical Relevance—Assessment of the UP:C ratio appears to be a reliable method for estimating 24-hour UPE in horses and ponies.
To evaluate effects of bite distance of an interlocking horizontal mattress epitendinous suture (IHMES) from the repair site on tensile strength of canine tendon repairs.
72 canine cadaveric superficial digital flexor tendons (SDFTs).
Transverse tenotomy was performed, and SDFTs were repaired with a locking-loop construct (LL construct) or 3 LL constructs with IHMES suture bites placed 5 (LL + 5ES construct), 10 (LL + 10ES construct), or 15 (LL + 15ES construct) mm from the transection site (18 SDFTs/group). Constructs were loaded to failure. Load at 1− and 3-mm gapping, yield force, failure load, and failure mode were evaluated.
Mean ± SD yield force and failure load for LL constructs were significantly lower than for IHMES constructs. Load at 1− and 3-mm gapping was significantly higher for IHMES constructs. Increasing the bite distance significantly increased construct strength (134.4 ± 26.1 N, 151.0 ± 16.8 N, and 182.1 ± 23.6 N for LL + 5ES, LL + 10ES, and LL + 15ES constructs, respectively), compared with strength for the LL construct. Failure mode differed significantly among constructs when an IHMES was used.
CONCLUSIONS AND CLINICAL RELEVANCE
Addition of an IHMES to an LL construct led to increased ultimate tensile strength by 2.5 times and significantly reduced gap formation. Increasing the IHMES bite distance increased yield force by 2.1, 2.3, and 2.7 times for bites placed 5, 10, and 15 mm from the tenotomy, respectively. Positioning an IHMES at a greater distance from the repair site provided superior biomechanical strength for tendon repairs in dogs.