Objective—To determine induction doses, anesthetic
constant rate infusions (CRI), and cardiopulmonary
effects of propofol in red-tailed hawks and great
horned owls and propofol pharmacokinetics in the
owls during CRI.
Animals—6 red-tailed hawks and 6 great horned
Procedure—The CRI dose necessary for a loss of
withdrawal reflex was determined via specific stimuli.
Anesthesia was induced by IV administration of
propofol (1 mg/kg/min) and maintained by CRI at the
predetermined dose for 30 minutes. Heart and respiratory
rates, arterial blood pressures, and blood gas
tensions were obtained in awake birds and at various
times after induction. End-tidal CO2 (ETCO2) concentration
and esophageal temperature were obtained
after induction. Propofol plasma concentrations were
obtained after induction and after completion of the
CRI in the owls. Recovery times were recorded.
Results—Mean ± SD doses for induction and CRI
were 4.48 ± 1.09 mg/kg and 0.48 ± 0.06 mg/kg/min,
respectively, for hawks and 3.36 ± 0.71 mg/kg and
0.56 ± 0.15 mg/kg/min, respectively, for owls.
Significant increases in PaCO2, HCO3, and ETCO2 in
hawks and owls and significant decreases in arterial
pH in hawks were detected. A 2-compartment model
best described the owl pharmacodynamic data.
Recovery times after infusion were prolonged and
varied widely. Central nervous system excitatory
signs were observed during recovery.
Conclusions and Clinical Relevance—Effects on
blood pressure were minimal, but effective ventilation
was reduced, suggesting the need for careful monitoring
during anesthesia. Prolonged recovery periods
with moderate-to-severe excitatory CNS signs may
occur in these species at these doses. (Am J Vet Res 2003;64:677–683)
Objective—To determine the effects that routine histologic
processing has on the dimensions of samples
of normal skin of dogs and assess whether the inclusion
of a muscle or fascial layer in such samples alters
Sample Population—Skin samples obtained from 6
medium-sized adult dogs with grossly normal skin.
Procedure—From each dog, skin samples (with or
without underlying fascia or muscle) were obtained
from 3 sites bilaterally (6 samples/dog) and processed
routinely for histologic evaluation; their dimensions
were measured at intervals during the experiment.
Results—As a result of processing, skin samples
decreased in size (combined percentage change in
length and width) and increased in thickness, compared
with their original dimensions. Samples without
fascia or muscle decreased in size by 21.1% to 32.0%
and increased in thickness by 45.1% to 75.8%. The
site of sample origin influenced processing-associated
changes in sample size but did not affect the
change in thickness. Decreases in dimensions did not
vary with inclusion of fascia but did vary with inclusion
of muscle. The change in thickness did not vary
with inclusion of a layer of fascia or muscle.
Conclusions and Clinical Relevance—Processing of
skin samples obtained from dogs for histologic evaluation
can cause changes in sample dimensions; samples
may decrease in length and width by as much as
32% and increase in thickness by 75.8%, compared
with their original dimensions. The presence of muscle
in canine skin samples can restrict the amount of
shrinkage in length or width associated with processing.
(Am J Vet Res 2005;66:500–505)
Objective—To determine the body condition score (BCS) distribution for dogs examined at a teaching hospital and examine whether the BCS distribution for dogs with cancer differed significantly from the distribution for dogs without cancer.
Sample Population—1,777 dogs with cancer and 12,893 dogs without cancer.
Procedures—A retrospective prevalence case-control study was conducted that used medical records from 1999 to 2004. Information was collected on BCS (9-point system), age, breed, sex, neuter status, diagnosis, and corticosteroid administration. Body condition score at the time of examination for cancer (dogs with cancer) or first chronologic visit (dogs without cancer) was recorded. Logistic regression was used to compare BCS prevalence distributions between groups.
Results—The overall prevalence of obese dogs (BCS ≥ 7/9) was 14.8% (2,169/14,670), and the overall prevalence of overweight dogs (BCS ≥ 6/9 to < 7/9) was 21.6% (3,174/14,670). There was a significant difference in the BCS distribution between dogs with and without cancer, with a slightly lower prevalence of being overweight and obese in dogs with cancer. The prevalence of obese and overweight dogs varied with specific cancer types when compared with the prevalence for dogs without cancer.
Conclusions and Clinical Relevance—Differences in obesity prevalence among cancer types is suggestive of an incongruous effect of this variable on cancer expression or a differential effect of specific cancer types on weight status. Systematic use of BCSs will help elucidate the association between obesity and cancer development.
Objective—To determine the pharmacokinetics of butorphanol tartrate after IV and IM single-dose administration in red-tailed hawks (RTHs) and great horned owls (GHOs).
Animals—6 adult RTHs and 6 adult GHOs.
Procedures—Each bird received an injection of butorphanol (0.5 mg/kg) into either the right jugular vein (IVj) or the pectoral muscles in a crossover study (1-week interval between treatments). The GHOs also later received butorphanol (0.5 mg/kg) via injection into a medial metatarsal vein (IVm). During each 24-hour postinjection period, blood samples were collected from each bird; plasma butorphanol concentrations were determined via liquid chromatography-mass spectrometry.
Results—2- and 1-compartment models best fit the IV and IM pharmacokinetic data, respectively, in both species. Terminal half-lives of butorphanol were 0.94 ± 0.30 hours (IVj) and 0.94 ± 0.26 hours (IM) for RTHs and 1.79 ± 1.36 hours (IVj), 1.84 ± 1.56 hours (IM), and 1.19 ± 0.34 hours (IVm) for GHOs. In GHOs, area under the curve (0 to infinity) for butorphanol after IVj or IM administration exceeded values in RTHs; GHO values after IM and IVm administration were less than those after IVj administration. Plasma butorphanol clearance was significantly more rapid in the RTHs. Bioavailability of butorphanol administered IM was 97.6 ± 33.2% (RTHs) and 88.8 ± 4.8% (GHOs).
Conclusions and Clinical Relevance—In RTHs and GHOs, butorphanol was rapidly absorbed and distributed via all routes of administration; the drug's rapid terminal half-life indicated that published dosing intervals for birds may be inadequate in RTHs and GHOs.
Objective—To determine the effect of feline herpesvirus type 1 (FHV-1) on tear film breakup time (TFBUT) and Schirmer tear test (STT) values in cats with primary experimental infection and to determine the relationship betweenTFBUT and STT values and conjunctival goblet cell density (GCD).
Sample Population—9 specific-pathogen–free cats of approximately 6 months of age.
Procedures—6 cats were inoculated with FHV-1; 3 control cats were sham inoculated. Clinical and histologic evidence of conjunctivitis and TFBUT, GCD, and STT values were assessed at multiple times until postinoculation day (PID) 29.
Results—In infected cats, mean clinical and histologic conjunctivitis scores peaked at PID 7 and remained above baseline at PID 29. In control cats, these 2 variables did not change from baseline throughout the study. MeanTFBUT declined rapidly in infected cats up to PID 15 and at PID 29 remained less than baseline, less than for control cats, and below refer-ence range values. Mean STT value for infected cats at PID 29 was increased from baseline but was within the reference range and not different from the value for control cats. Mean GCD in infected cats declined precipitously by PID 7 and remained below reference range values at PID 29. Mean GCD in control cats remained unchanged for the duration of the study period.
Conclusions and Clinical Relevance—FHV-1 induced qualitative tear film abnormalities in experimentally infected cats, as measured by TFBUT and GCD. Assessment of TFBUT provided a reasonable clinical estimate of GCD.
Objective—To evaluate the effects of 4.7-mg deslorelin acetate implants on egg production and plasma concentrations of 17β-estradiol and androstenedione in Japanese quail (Coturnix coturnix japonica) over 180 days and assess safety of the implants in quail via gross and histologic examination.
Animals—20 female Japanese quail.
Procedures—Following a 7-day period of consistent egg laying, quail were anesthetized and received a 4.7-mg deslorelin implant (treatment group; n = 10) or identical placebo implant (control group; 10) SC between the scapulae. Egg production was monitored daily. Plasma concentrations of 17β-estradiol and androstenedione were measured on days 0 (immediately prior to implant injection), 14, 29, 62, 90, 120, 150, and 180 via radioimmunoassay. Birds were weighed periodically and euthanized at day 180 for complete necropsy.
Results—Egg production was significantly decreased in the treatment group, compared with the control group, from 2 to 12 weeks after implant injection. Egg production ceased in 6 of 10 quail in the treatment group (mean duration of cessation, 70 days). Plasma androstenedione and 17β-estradiol concentrations were significantly lower on day 29 in the treatment group than in the control group. Plama androstenedione and 17β-estradiol concentrations were significantly lower on day 29 in the treatment group then in the control group.
Conclusions and Clinical Relevance—4.7-mg deslorelin acetate implants reversibly decreased egg laying for approximately 70 days in most of the Japanese quail evaluated. Further studies evaluating implants containing different concentrations of the drug are needed in quail and other avian species.
Objective—To quantitatively and qualitatively compare electroretinography (ERG) recordings in awake, sedated, and anesthetized dogs.
Animals—Six 6-month-old Beagles.
Procedures—A brief ERG protocol for dogs was used. Following 1-minute and subsequent 5-minute dark adaptation, mixed rod-cone responses were recorded bilaterally with a handheld multispecies ERG device with dogs in each of 3 states of consciousness: awake, sedated (dexmedetomidine and butorphanol), and anesthetized (atropine and hydromorphone, followed by propofol and midazolam and anesthetic maintenance with isoflurane). Low- and high-frequency noise levels were quantified via Fourier analysis, and the effect of consciousness state on signal amplitude, implicit time, and noise was analyzed via repeated-measures ANOVA. In addition, 13 veterinary ophthalmologists who were unaware of the dogs’ consciousness states subjectively graded the ERG recording quality, and scores for each tracing were compared.
Results—ERG amplitudes were highest in awake dogs and lowest in anesthetized dogs. Implicit times were shortest in awake dogs and longest in anesthetized dogs. Differences in b-wave amplitudes and a-wave implicit times were significant. Neither low- nor high-frequency noise levels differed significantly among consciousness states. Furthermore, no significant differences were identified among observers’ scores assigned to ERG tracings.
Conclusions and Clinical Relevance—Anesthesia and sedation resulted in significant attenuation and delay of ERG responses in dogs. Chemical restraint of dogs had no consistently significant effect on low- or high-frequency noise levels or on observer perception of signal quality.
Objective—To characterize clinicopathologic features of the most common odontogenic tumors and focal fibrous hyperplasia (FFH) in dogs.
Design—Retrospective case series.
Animals—152 dogs evaluated for oral tumors of possible odontogenic origin at the William R. Pritchard Veterinary Medical Teaching Hospital of the University of California-Davis between 1995 and 2005.
Procedures—Information was collected from records, including dog breed, age, reproductive status, and location of lesion in the oral cavity. Histologic slides pertaining to each dog were reviewed by 3 investigators. Data regarding clinicopathologic features of the 3 most common lesions (canine acanthomatous ameloblastoma [CAA], peripheral odontogenic fibroma [POF], and FFH) were summarized.
Results—152 dogs with odontogenic tumors or FFH were identified. Sixty-eight (45%) dogs had CAA, 47 (31 %) had POF, 24 (16%) had FFH, and 13 (9%) had other odontogenic tumors. Canine acanthomatous ameloblastoma was present most commonly in the rostral aspect of the mandible, with POF and FFH more common in the rostral aspect of the maxilla. Males and females were equally represented among dogs with CAA and FFH. Castrated males were overrepresented among dogs with POF. Golden Retrievers, Akitas, Cocker Spaniels, and Shetland Sheepdogs were overrepresented among dogs with CAA. No breed predisposition was detected for FFH or POF. Dogs with FFH had a greater mean age at initial evaluation than did dogs with CAA or POF.
Conclusions and Clinical Relevance—CAA, POF, and FFH have distinct clinical patterns that may help clinicians and pathologists identify such lesions more readily.
Objective—To characterize clinical signs and histologic findings in dogs with odontogenic cysts and determine whether histologic findings were associated with clinical features.
Design—Retrospective case series.
Procedures—Medical records were reviewed to obtain clinical data, including breed, age, sex, and lesion location. Microscopic sections and results of diagnostic imaging were reviewed.
Results—Odontogenic cysts were identified in 41 dogs between 1995 and 2010. There were 29 dogs with dentigerous cysts, 1 with a radicular cyst, 1 with a lateral periodontal cyst, and 1 with a gingival inclusion cyst. In addition, 9 dogs with odontogenic cysts that had clinical and histologic features suggestive of, but not diagnostic for, odontogenic keratocysts seen in people were identified. In all 9 dogs, these cysts were located in the maxilla and surrounded the roots of normally erupted teeth. Of the 29 dogs with dentigerous cysts, 23 had a single cyst, 5 had 2 cysts, and 1 had 3 cysts. Six cysts were associated with an unerupted canine tooth, and 30 were associated with an unerupted first premolar tooth (1 cyst was associated both with an unerupted canine tooth and with an unerupted first premolar tooth). Dentigerous cysts were identified in a variety of breeds, but several brachycephalic breeds were overrepresented, compared with the hospital population during the study period.
Conclusions and Clinical Relevance—Results suggested that a variety of odontogenic cysts can occur in dogs. In addition, cysts that resembled odontogenic keratocysts reported in people were identified. We propose the term canine odontogenic parakeratinized cyst for this condition.
Objective—To determine CSF characteristics associated with intracranial meningiomas in dogs.
Design—Retrospective case series.
Animals—56 dogs with intracranial meningiomas.
Procedures—Medical records of dogs with a histopathologic diagnosis of intracranial meningioma, in which CSF analysis had been performed, were reviewed. Information concerning total nucleated cell counts (TNCCs) and differential nucleated cell counts, RBC counts, and total protein concentration in CSF; seizure history and glucocorticoid administration; and location of meningiomas was recorded.
Results—TNCCs < 5 cells/μL were detected in 41 of 56 (73%) dogs; 5 of 56 (9%) dogs had TNCCs > 50 cells/μL. Analysis of CSF revealed predominantly neutrophilic pleocytosis in < 20% of dogs. There was a significant association between meningioma location (caudal portion of the cranial fossa or middle and rostral portion of the cranial fossae) and increased TNCCs (≥ 5 cells/μL).
Conclusions and Clinical Relevance—Results were significantly different from those routinely reported in the veterinary literature. Neutrophilic pleocytosis, especially with TNCCs > 50 cells/μL, was not typical in CSF samples from dogs with intracranial meningiomas. Neutrophilic pleocytosis may not be detected in CSF samples from dogs with meningiomas located within the middle or rostral portion of the cranial fossae.