Timing of and risk factors for deep surgical site infection requiring implant removal following canine tibial plateau leveling osteotomy.

OBJECTIVE: To identify demographic risk factors for deep surgical site infection (SSI) requiring tibial plateau leveling osteotomy (TPLO) implant removal and time to implant removal. ANIMALS: Four hundred and thirty-three dogs that underwent a TPLO (144 that developed a deep SSI and required implant removal, 289 that did not). STUDY DESIGN: Retrospective case-control study. METHODS: Records of dogs undergoing implant removal due to a deep SSI after TPLO between 2006 and 2018 at two referral centers were reviewed. These records were frequency-matched by date to dogs undergoing TPLO that did not require implant removal. Multivariable analyses tested associations between demographics and implant removal as well as timing of implant removal. RESULTS: Deep SSI and implant removal occurred in 144 of 4813 (3.0%; 95% CI: 2.5, 3.5) dogs treated with TPLO. Implant removal was performed at a median of 279 days (range 49-2394 days) postoperatively. Male dogs (OR 1.8; 95% CI: 1.2, 2.7) and German Shepherd dogs (GSDs) (OR 7.4; 95% CI: 2.6, 20.5) were associated with plate removal. Earlier TPLO plate removal was associated with GSDs only (HR 2.4; 95% CI: 1.4, 4.1). CONCLUSION: Implant removal due to SSI after TPLO was uncommon, although male dogs and GSDs seemed predisposed to this complication. SIGNIFICANCE: These demographic risk factors can be used to educate owners regarding perioperative management.

External ear cytological results and resident flora of clinically normal alpacas (Vicugna pacos).

BACKGROUND: Otitis is common in alpacas. Suppurative otitis media/interna can be an extension from the external ear canal or from a respiratory infection. Cytological evaluation provides rapid and inexpensive information to assist in therapeutic decision; to date, there is no published information regarding the normal cytological results and flora of the alpaca external ear canal. HYPOTHESIS/OBJECTIVES: To describe normal resident cytological findings and flora and possible variation over time, we sampled clinically normal alpaca external ear canals during two different seasons. ANIMALS: Fifty privately owned, healthy alpacas of different ages and sexes in two northeastern United States flocks. METHODS AND MATERIALS: One ear per alpaca had both cytological swabs (ectoparasites, inflammatory and epithelial cells, bacteria and yeast) and sterile swabs (bacterial and fungal cultures) taken. This was done in August 2017 and repeated in January 2018. RESULTS: Yeast organisms were noted cytologically in 2-4% of the samples. Prevalence of total yeast genera was 6% in August and 30% in January. Cytologically, rod-shaped bacteria [maximum 4-10/high power field (HPF); median 0-0.5/HPF] were seen in 50% of alpacas in August and 26% in January. Coccal bacteria (maximum 6-10/HPF; median 0/HPF) were seen in 32% of alpacas in August and 16% in January. No statistically significant findings were noted between sampling months. Common bacterial genera isolated in August were Bacillus (44%), Arthrobacter (40%) and nonhaemolytic Staphylococcus (26%), and in January were Bacillus (42%) and Pantoea (38%). CONCLUSIONS AND CLINICAL IMPORTANCE: This information may be useful when evaluating alpaca external ear canal samples, which subsequently may help dictate empirical therapy.

Histological, electrophysiological and clinical effects of thermal radiofrequency therapy of the saphenous nerve and pulsed radiofrequency therapy of the sciatic nerve in dogs.

OBJECTIVE: Thermal radiofrequency (TRF) of the saphenous nerve (a sensory nerve) combined with pulsed radiofrequency (PRF) of the sciatic nerve (a sensory and motor nerve) might relieve intractable stifle osteoarthritis (OA) pain in dogs. The objective was to determine if saphenous nerve TRF induces Wallerian degeneration and if sciatic nerve PRF induces degeneration or dysfunction. STUDY DESIGN: Blinded, controlled, randomized, preclinical study. ANIMALS: A group of six intact, female Beagle dogs aged 14-16 months. METHODS: In each dog, one pelvic limb was assigned randomly to the control group and the other to the treatment group. Dogs were anesthetized and, using ultrasonography, radiofrequency electrodes were positioned adjacent to saphenous and sciatic nerves bilaterally; TRF and PRF were performed only in the treatment limb. Motor nerve conduction velocity (MNCV) was measured in both sciatic nerves 2 weeks later, and the dogs were euthanized. Hematoxylin and eosin-stained sections of saphenous and sciatic nerves were examined using light microscopy. Degeneration and inflammation were scored 0 (none) to 3 (severe). A one-tailed, paired Wilcoxon signed-rank test was used to test for differences in scores and MNCV between control and treatment nerves. RESULTS: Degeneration and inflammation scores were higher in treatment saphenous nerves in 5/6 dogs [83%; 95% confidence interval (CI), 36%, 99%]; however, after Bonferroni correction only degeneration score was higher (p = 0.0313). Degeneration, inflammation or decreased MNCV were not observed in sciatic nerves (each outcome: 0/6 nerves, 0%; 95% CI, 0%, 48%). No dogs experienced postprocedural pain or neurological deficits. CONCLUSIONS AND CLINICAL RELEVANCE: The degeneration in TRF-treated saphenous nerves appears sufficient to impair transmission. Sciatic nerve PRF did not cause degeneration with attendant motor deficits, consistent with a proposed neuromodulatory mechanism. A clinical trial is needed to confirm the combined techniques produce analgesia without motor deficits in dogs with stifle OA.

Dogs with acute myeloid leukemia or lymphoid neoplasms (large cell lymphoma or acute lymphoblastic leukemia) may have indistinguishable mediastinal masses on radiographs.

Acute myeloid leukemia is an uncommon hematopoietic neoplasm of dogs that should be differentiated from lymphoid neoplasms, such as lymphoma, because of different treatment protocols and a worse prognosis. Thoracic radiography is performed frequently in dogs with suspected hematopoietic neoplasia, and detecting a mediastinal mass often prioritizes lymphoma as the most likely diagnosis. However, we have observed a mediastinal mass in several dogs with acute myeloid leukemia and hypothesized that (1) the frequency of a mediastinal mass was higher and (2) the size of the mass was larger in dogs with acute myeloid leukemia compared to dogs with lymphoid neoplasms. In this analytical study (observational, retrospective, and cross-sectional), the sample population included 238 dogs with hematopoietic neoplasia. These dogs were divided into lymphoid (large cell lymphoma, acute lymphoblastic leukemia) and myeloid groups based on standard phenotyping tests. A mediastinal mass was detected during thoracic radiography in 73/218 (33%) and nine of 20 (45%) dogs in the lymphoid and myeloid groups (P = 0.21), respectively. The median size ratio of mediastinal mass to cardiac silhouette was 0.20 and 0.23 in the lymphoid and myeloid groups (P = 0.96), respectively. Additionally, we observed normal thoracic radiographs in 111/218 (51%) dogs in the lymphoid group and nine of 20 (45%) dogs in the myeloid group. In conclusion, acute myeloid leukemia should be considered when a mediastinal mass is detected during radiography in dogs with suspected hematopoietic neoplasia-but the presence or size of a mediastinal mass does not differentiate between myeloid and lymphoid neoplasms.

THE PASSAGE AND DURATION OF ANTIBODIES TO WEST NILE VIRUS IN HUMBOLDT PENGUINS (SPHENISCUS HUMBOLDTI).

West Nile virus (genus Flavivirus) outbreaks and mortality events have been documented in both wild and captive avian species, including penguins. Serologic response to vaccination in avian species has varied and appears to be largely species dependent; however, Humboldt penguins ( Spheniscus humboldti ) previously showed excellent rates of seroconversion. The goal of this study was to determine virus neutralization titers of 17 Humboldt penguin hens and their subsequent eggs, chicks, or both following vaccination with a killed West Nile vaccine. Chicks were also vaccinated at 56, 70, and 84 days old. Titers were measured from 10-346 days prior to lay as well as serially in seven chicks. Data collected showed positive rank correlation between maternal titers and yolk titers (ρ = 0.90, P < 0.0001, n = 14) but no association between booster vaccination and yolk titers. All seven chicks had detectable antibody on days 14 and 28, and antibody levels had increased (relative to day 56) in 3 of 6 chicks (50%; 95% confidence interval 14-86%) by day 112. Further information is provided on a suggested vaccination schedule for Humboldt penguin chicks based on a time-dependent decline in maternal antibody titers. Cell-mediated immunity and experimental challenge following vaccination have not yet been investigated in this species.

Ectopic Trophoblast Allografts in the Horse Resist Destruction by Secondary Immune Responses.

Invasive trophoblast from Day 34 horse conceptuses survives in extrauterine sites in allogeneic recipients that are immunologically naive to donor major histocompatibility complex class I antigens. The ectopic trophoblast retains its in utero characteristics, including similar lifespan, physiologic effect of its secreted product (equine chorionic gonadotropin) upon the recipient's ovaries, and induction of host immune responses. Immunologic memory has not been considered previously in this experimental system. We hypothesized that primary exposure to ectopic trophoblast would affect the recipient's immune status such that the survival time of subsequent transplants would be altered. Secondary transplant lifespans could be shortened by destructive memory responses, as has been observed in ectopic trophoblast studies in rodents, or lengthened, as occurs when male skin grafts follow multiple syngeneic pregnancies in mice. Eight mares received two closely spaced trophoblast transplants. Both grafts for each recipient were obtained from conceptuses sired by the same stallion to provide consistency in histocompatibility antigen exposure. Donor stallions were major histocompatibility complex class I homozygotes. Cytotoxic antibody production was tracked to monitor recipients' immune responses to the transplants. Detection of serum equine chorionic gonadotropin was used as a proxy for transplant lifespan. There was no significant difference between the distributions of primary and secondary transplant lifespans, despite evidence of immunologic memory. These data demonstrate that secondary ectopic trophoblast transplants in horses do not experience earlier destruction or prolonged survival following immune priming of recipients. Mechanisms responsible for the eventual demise of the transplants remain unperturbed by secondary immune responses or chronic antigenic exposure.

CORRELATIONS AMONG ULTRASONOGRAPHIC MEASUREMENTS OF OPTIC NERVE SHEATH DIAMETER, AGE, AND BODY WEIGHT IN CLINICALLY NORMAL HORSES.

Early diagnosis of high intracranial pressure (ICP) is critical for minimizing progressive brain injury due to reduced cerebral perfusion. In people, detecting enlargement of the optic nerve sheath diameter (ONSD) by transpalpebral ultrasonography has been found to be an accurate test for high ICP. Aims of this prospective, observational, cross-sectional study were to test hypotheses that (1) ultrasonographic measurement of ONSD would be repeatable in horses, (2) have acceptable interobserver agreement, and (3) would be correlated with age and body weight. The sample population included 48 horses without clinical signs of high ICP and with varying ages and body weights. Two observers independently performed ONSD measurements in both eyes. All measurements ranged from 2.6 to 6.5 mm. The mean difference of repeated measures within observers was ≤0.1 mm and the coefficients of variation ranged from 5.0% to 8.8%. The mean difference of measures between observers was ≤0.2 mm. After correcting for performing multiple tests, no significant rank correlation (all r < 0.4 [absolute value]) was detected between ONSD and age or body weight. However, we observed smaller ONSD in foals versus adults (all P ≤ 0.002). In the foals, all observed measures of rostrocaudal and dorsoventral ONSD were <5 mm. In the adults, all observed measures of rostrocaudal and dorsoventral ONSD were ≤6.5 mm. Findings indicated that ultrasonographic ONSD measurement is a feasible test for use in horses of varying ages and sizes. Further investigation of this ultrasonographic measure as a clinical test for horse with suspected high ICP is warranted.

LABORATORY VALIDATION OF A POINT-OF-CARE CARDIAC TROPONIN I ASSAY FOR USE IN WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS).

The VetScan® i-STAT® 1 Handheld Analyzer and cardiac troponin I (cTnI) cartridges (i-STAT cTnI assay) measured greater median cTnI concentration [cTnI] in free-ranging white-tailed deer (Odocoileus virginianus) hand-injected with anesthetic drugs after physical restraint in Clover traps than in those ground-darted with the same drugs. This suggested that Clover trapping induces myocardial damage, bringing the use of this capture method under scrutiny. The purpose of this study was to confirm the validity of the i-STAT cTnI assay in deer before recommending changes in capture methods. Median [cTnI] measured by the i-STAT cTnI assay ([cTnI]i) in heparinized whole blood collected from 52 healthy, reproductively mature, female deer physically restrained in a chute was 0.01 ng/ml (10-90% percentiles: 0.00-0.03 ng/ml; minimum, maximum: 0.00, 0.07 ng/ml); [cTnI]i was 0.00 ng/ml in 42% of the deer. There was no association between [cTnI]i and either clotting or hemolytic index. [cTnI]i was 0.00 ng/ml when deer skeletal muscle homogenate was added to deer blood with [cTnI]i of 0.00 ng/ml, confirming the i-STAT cTnI assay does not detect skeletal muscle troponins. When deer cardiac muscle homogenate was serially diluted with 1) deer blood, 2) deer plasma, and 3) cow blood, [cTnI]i was directly proportional (Y intercept=-0.09, 0.7, and -0.08 ng/ml, respectively; r2≥0.97) to the fraction of homogenate in each sample. Deer cardiac muscle homogenate was diluted with deer blood to produce three samples with low, intermediate, and high [cTnI]i; serial measurements (n=10) performed on each sample yielded coefficients of variation (CVs) of 8, 20, and 11%, respectively. Corresponding CVs when plasma was used as diluent were 13, 9, and 7%, respectively. [cTnI]i increased when plasma with a low [cTnI]i was stored at 20-24°C for 9 days. Three freeze-thaw cycles caused no systematic change in plasma [cTnI]i.

Lack of evidence that avian oncogenic viruses are infectious for humans: a review.

Chickens may be infected with three different oncogenic viruses: avian leukosis virus (ALV), reticuloendotheliosis virus (REV), and Marek's disease herpesvirus (MDV). Several epidemiological studies have suggested a link between these viruses and different types of cancer in people working in poultry processing plants and with multiple sclerosis. In this article, we analyze the epidemiological evidence that these viruses are causative agents for human cancer, followed by description of the relevant key characteristics of ALV, REV, and MDV. Finally, we discuss the biological evidence or lack thereof that avian tumor viruses are involved in the etiology of human cancer and multiple sclerosis (MS). The recent primary epidemiologic articles that we reviewed as examples were only hypothesis-generating studies examining massive numbers of risk factors for associations with various imprecise, non-viral-specific outcomes. The studies lacked precise evidence of exposure to the relevant viruses and the statistical methods failed to adjust for the large risks of false-positive claims. ALV subgroups A-D and J have been eradicated in the United States from the pure lines down to the parent stocks by the breeder companies, which have greatly reduced the incidence of infection in layer flocks and broilers. As a consequence, potential exposure of humans to these viruses has greatly diminished. Infection of humans working in processing plants with ALV-A and ALV-B is unlikely, because broilers are generally resistant to infection with these two subgroups. Moreover, these viruses enter cells by specific receptors present on chicken, but not on mammalian, cells. Infection of mammalian cell cultures or animals with ALV-A, ALV-B, and ALV-J has not been reported. Moreover, humans vaccinated with exogenous or endogenous ALV-contaminated vaccines against yellow fever, measles, and mumps did not become antibody- or virus-positive for ALV. The risks for human infection with REV are similarly limited. First of all, REV also has been eradicated from pure lines down to parent stock by breeder companies in the United States. Broilers can still become infected with REV through infection with fowl pox virus containing REV. However, there is no indication that REV can infect human cells. Low levels of antibodies to ALV and REV in human sera have been reported by a few groups. Absorption of sera with chicken antigens reduced the antibody titers, and there was no clear association with contacts with poultry. Possible cross-reactions with human endogenous or exogenous retroviruses were not considered in these publications. MDV is typically associated with infection of chickens, and almost all experimental data show that MDV cannot infect mammalian cells or animals, including nonhuman primates. One study reports the presence of MDV gD DNA in human sera, but this finding could not be confirmed by another group. A Medline search of the term "gene expression in human cancers" was negative for publications with avian retroviruses or MDV. In conclusion, there is no indication that avian oncogenic viruses are involved in human cancer or MS or even able to infect and replicate in humans.

An investigation of the discrepancy between set and actual temperature of neonatal incubators: concern for hypothermia and hyperthermia.

OBJECTIVE: To document any discordance between the set temperature and independently measured temperature of neonatal incubators in order to determine the potential of neonatal incubators to cause hypothermia or hyperthermia in neonatal animals. SAMPLE: 5 different veterinary neonatal incubators from 2 separate manufacturers. METHODS: Internal temperatures of 5 incubators from 2 manufacturers were monitored with both internal and external monitoring devices to determine how much incubator temperatures might vary from what is reported on the incubator thermostat. The study was conducted on May 25, 2022. RESULTS: Increases in temperature as measured by thermocouple and infrared sensors of > 2 °C were detected in 3 of the 5 (60%; 95% CI, 17% to 93%) tested incubators. Temperatures exceeded 41 °C at times, despite the incubator thermostat being set to 35 °C. CLINICAL RELEVANCE: Neonatal puppies have a decreased capacity to thermoregulate and are susceptible to both hypothermia and hyperthermia if environmental temperatures are not kept within a proper range. Core temperatures below 35.0 °C lead to bradycardia, dyspnea, loss of suckle reflex, hypoglycemia, gastrointestinal ileus, and multiple organ failure; temperatures above 41.1 °C lead to pulmonary edema, petechial and ecchymotic hemorrhage in multiple organs, and death.

Association of partial pressure of carbon dioxide in expired gas and arterial blood at three different ventilation states in apneic chickens (Gallus domesticus) during air sac insufflation anesthesia.

OBJECTIVE: To test whether partial pressure of CO2 in expired gas (PECO2) predicts the partial pressure of CO2 in arterial blood (PaCO2) in apneic chickens during air sac insufflation anesthesia at three different ventilation states. SECONDARY OBJECTIVE: To determine the PECO2 at which apnea occurs during air sac insufflation anesthesia. STUDY DESIGN: Randomized cross-over study. ANIMALS: Twenty-three healthy male white leghorn chickens. METHODS: Chickens were anesthetized via mask with isoflurane in oxygen and an air sac cannula was placed in the right abdominal air sac. Delivery of isoflurane in O2 was transferred from the mask to the air sac cannula. The birds were maintained at a surgical plane of anesthesia and apnea was induced by adjusting gas flow; the PECO2 at apnea was recorded. The birds were then paralyzed and gas flow was adjusted to achieve three different PECO2 s in random order: 43 mmHg (5.6 kPa) [hypoventilation]; 33 mmHg (4.3 kPa) [normoventilation]; and 23 mmHg (3.0 kPa) [hyperventilation]. After maintaining the target expired isoflurane concentration (EIso; 1.85 or 1.90%) and PECO2 for 15 minutes, arterial blood gas analysis was performed to determine the PaCO2 . The chickens were euthanized at the end of the experiment. RESULTS: Based on Bland-Altman comparisons, PECO2 was not strongly associated with PaCO2 during the three ventilation states. The PECO2 at which apnea occurred varied {median (minimum, maximum): 35 (30, 48) mmHg [4.6 (3.9, 6.2) kPa]}. CONCLUSIONS: Measured PECO2 cannot be used in a simple linear fashion to predict PaCO2 in birds during air sac insufflation anesthesia. The PECO2 at which apnea occurs during air sac insufflation anesthesia is not predictable. CLINICAL RELEVANCE: Arterial blood gases should be used to monitor CO2 during air sac insufflation anesthesia to verify appropriate patient ventilation.

Invited review: study design considerations for clinical research in veterinary radiology and radiation oncology.

High quality clinical research is essential for advancing knowledge in the areas of veterinary radiology and radiation oncology. Types of clinical research studies may include experimental studies, method-comparison studies, and patient-based studies. Experimental studies explore issues relative to pathophysiology, patient safety, and treatment efficacy. Method-comparison studies evaluate agreement between techniques or between observers. Patient-based studies investigate naturally acquired disease and focus on questions asked in clinical practice that relate to individuals or populations (e.g., risk, accuracy, or prognosis). Careful preplanning and study design are essential in order to achieve valid results. A key point to planning studies is ensuring that the design is tailored to the study objectives. Good design includes a comprehensive literature review, asking suitable questions, selecting the proper sample population, collecting the appropriate data, performing the correct statistical analyses, and drawing conclusions supported by the available evidence. Most study designs are classified by whether they are experimental or observational, longitudinal or cross-sectional, and prospective or retrospective. Additional features (e.g., controlled, randomized, or blinded) may be described that address bias. Two related challenging aspects of study design are defining an important research question and selecting an appropriate sample population. The sample population should represent the target population as much as possible. Furthermore, when comparing groups, it is important that the groups are as alike to each other as possible except for the variables of interest. Medical images are well suited for clinical research because imaging signs are categorical or numerical variables that might be predictors or outcomes of diseases or treatments.

T2-weighted magnetic resonance imaging measurements of optic nerve sheath diameter in dogs with and without presumed intracranial hypertension.

Intracranial hypertension is a cause of cerebral ischemia and neurologic deficits in dogs. Goals of this retrospective study were to test interobserver agreement for MRI measurements of optic nerve sheath diameter and associations between optic nerve sheath diameter, signalment data, and presumed intracranial hypertension status in a cohort of dogs. A veterinary radiologist interpreted scans of 100 dogs and dogs were assigned to groups based on presence or absence of at least two MRI characteristics of presumed intracranial hypertension. Two observers who were unaware of group status independently measured optic nerve diameter from transverse T2-weighted sequences. Mean optic nerve sheath diameter for all dogs was 3 mm (1-4 mm). The mean difference between observers was 0.3 mm (limits of agreement, -0.4 and 1.0 mm). There was no correlation between optic nerve sheath diameter and age for either observer (r = -0.06 to 0.00) but a moderate positive correlation was observed between optic nerve sheath diameter and body weight for both observers (r = 0.70-0.76). The 22 dogs with presumed intracranial hypertension weighed less than the 78 dogs without (P = 0.02) and were more often female (P = 0.04). Dogs with presumed intracranial hypertension had a larger ratio of optic nerve sheath diameter to body weight for each observer-side pair (P = 0.01-0.04) than dogs without. Findings indicated that the ratio of MRI optic nerve sheath diameter relative to body weight may be a repeatable predictor of intracranial hypertension in dogs.

Progesterone Analysis in Canine Breeding Management.

Progesterone is a worthwhile addition to the clinical assessment of cycle stage for breeding, elective cesarian delivery, and reproductive management in the bitch if reliably measured. Clinical decisions based on systemic progesterone concentrations also require the rapid return of results. Most commercially accessible analyses capable of returning results within a day still rely primarily on immunoassays of one kind or another. Point-of-care instruments utilizing similar technology have been developed more recently to enable results to be generated in-house. Repeated monitoring of progesterone on whatever platform can be useful if consistent collection and analysis protocols ensure acceptable precision, accuracy, and repeatability.

Comparison of bupivacaine femoral and sciatic nerve block versus bupivacaine and morphine epidural for stifle surgery in dogs.

OBJECTIVE: To evaluate the efficacy of combined femoral and sciatic nerve blocks as an alternative to epidural anesthesia and analgesia in dogs undergoing stifle surgery under general anesthesia. STUDY DESIGN: Prospective, blinded, randomized, clinical comparison. ANIMALS: Twenty dogs weighing 37 ± 11 (mean ± SD) kg, aged 3 (1-8) [median (minimum-maximum)] years undergoing elective unilateral tibial-plateau leveling osteotomy. METHODS: Dogs were assigned randomly to receive either epidural anesthesia (bupivacaine 0.5%, 0.5 mg kg(-1) + morphine 0.1%, 0.1 mg kg(-1), in 0.2 mL kg(-1); EPID) or femoral and sciatic nerve blocks (Bupivacaine 0.5%, 0.1 mL kg(-1), was administered at each site; F + S) guided by electrolocation. All patients received a standard general anesthesia technique. Pain and sedation were scored (on scales of 0-10 and 0-3, respectively) pre-operatively, at extubation, and at 1, 4 and then every 4 hours thereafter up to 24 hours. Postoperatively, hydromorphone was administered to any patient with a pain score of >5 or whenever the blinded caregiver determined that more hydromorphone was necessary. Intraoperative heart rate (HR), mean arterial pressure (MAP), end tidal isoflurane (FE'ISO), body temperature, post-operative pain scores, time to first hydromorphone dose after surgery, time to first feeding, time to first drinking, time to first urination, time to first ambulation (walk on a lead) and cumulative dose of hydromorphone were recorded. RESULTS: Intra-operatively, FE'ISO and MAP were significantly lower in the EPID group (p = 0.05 and p = 0.04, respectively). Postoperatively, the cumulative hydromorphone consumption (p = 0.04) and the incidence of urinary retention (p = 0.03) were higher in the EPID group. CONCLUSION AND CLINICAL RELEVANCE: F + S is a practical alternative to EPID that produces less urine retention and reduces opioid consumption in the 24 hours after surgery. EPID might be associated with a lower isoflurane requirement and lower systemic blood pressure.

Functions of ectopically transplanted invasive horse trophoblast.

The invasive and fully antigenic trophoblast of the chorionic girdle portion of the equine fetal membranes has the capacity to survive and differentiate after transplantation to ectopic sites. The objectives of this study were to determine i) the survival time of ectopically transplanted allogeneic trophoblast cells in non-pregnant recipient mares, ii) whether equine chorionic gonadotropin (eCG) can be delivered systemically by transplanted chorionic girdle cells, and iii) whether eCG delivered by the transplanted cells is biologically active and can suppress behavioral signs associated with estrus. Ectopically transplanted chorionic girdle survived for up to 105 days with a mean lifespan of 75 days (95% confidence interval 55-94) and secreted sufficient eCG for the hormone to be measurable in the recipients' circulation. Immunohistochemical labeling of serial biopsies of the transplant sites and measurement of eCG profiles demonstrated that graft survival was similar to the lifespan of equine endometrial cups in normal horse pregnancy. The eCG secreted by the transplanted cells induced corpora lutea formation and sustained systemic progesterone levels in the recipient mares, effects that are also observed during pregnancy. This in turn caused suppression of estrus behavior in the recipients for up to 3 months. Thus, ectopically transplanted equine trophoblast provides an unusual example of sustained viability and function of an immunogenic transplant in a recipient with an intact immune system. This model highlights the importance of innate immunoregulatory capabilities of invasive trophoblast cells and describes a new method to deliver sustained circulating concentrations of eCG in non-pregnant mares.

Evaluation of factors associated with second remission in dogs with lymphoma undergoing retreatment with a cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy protocol: 95 cases (2000-2007).

OBJECTIVE: To evaluate factors associated with second remission in dogs with lymphoma retreated with a cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) protocol after relapse following initial treatment with a first-line 6-month CHOP protocol. DESIGN: Retrospective case series. ANIMALS: 95 dogs with lymphoma. PROCEDURES: Medical records were reviewed. Remission duration was estimated by use of the Kaplan-Meier method. Factors potentially associated with prognosis were examined. RESULTS: Median remission duration after the first-line CHOP protocol was 289 days (range, 150 to 1,457 days). Overall, 78% (95% confidence interval [CI], 69% to 86%) of dogs achieved a complete remission following retreatment, with a median second remission duration of 159 days (95% CI, 126 to 212 days). Duration of time off chemotherapy was associated with likelihood of response to retreatment; median time off chemotherapy was 140 days for dogs that achieved a complete remission after retreatment and 84 days for dogs that failed to respond to retreatment. Second remission duration was associated with remission duration after initial chemotherapy; median second remission duration for dogs with initial remission duration ≥ 289 days was 214 days (95% CI, 168 to 491 days), compared with 98 days (95% CI, 70 to 144 days) for dogs with initial remission duration < 289 days. CONCLUSIONS AND CLINICAL RELEVANCE: Findings suggested that retreatment with the CHOP protocol can be effective in dogs with lymphoma that successfully complete an initial 6-month CHOP protocol.

Twitch potentiation: a potential source of error during neuromuscular monitoring with acceleromyography in anesthetized dogs.

OBJECTIVE: To measure twitch potentiation (the staircase phenomenon) in anesthetized dogs, and assess its relevance during neuromuscular monitoring with acceleromyography (AMG). STUDY DESIGN: Randomized, prospective clinical trial. ANIMALS: Sixteen dogs undergoing ovariohysterectomy. METHODS: Under isoflurane anesthesia, neuromuscular function was monitored with train-of-four (TOF) stimuli every 15 seconds and quantified by AMG. Neuromuscular blockade (NMB) was produced with 0.15 mg kg(-1) atracurium IV. Dogs were randomly divided into two groups; a potentiation group (PG) in which TOF stimulation was applied for 20 minutes before atracurium was administered; and a control group (CG) where no such time was allowed. In both groups, the AMG was calibrated (at tCAL) just before atracurium was administered. TOF stimulation continued throughout the experiment in all dogs. The height of the first twitch (T(1)) (expressed as a fraction of T(1) at tCAL) and train-of-four ratio (TOFR) were recorded until TOFR returned to ≥90%. RESULTS: In PG, T(1) increased significantly (p = 0.0078) from a median of 102% (range, 95, 109) at baseline to 118% (100, 142) at 20 minutes. In PG, no difference was found between T(1) at tCAL (immediately before atracurium administration) and T(1) when neuromuscular transmission returned (p = 0.42). In the CG, T(1) increased significantly between tCAL and the time neuromuscular transmission returned (p = 0.027). TOFR did not increase during twitch potentiation (all p = 0.32). CONCLUSIONS AND CLINICAL RELEVANCE: T(1) increased significantly during 20 minutes of uninterrupted TOF stimulation in the absence of NMB, establishing that twitch potentiation occurs in anesthetized dogs. With no time for potentiation, T(1) increased during the course of recovery from NMB; this phenomenon introduces a bias in T(1) measurements and could affect studies reporting potency and duration of NMB based on T(1) or single twitches. TOFR was unaltered by potentiation emphasizing its clinical usefulness for excluding post-operative residual NMB.

A randomized, blinded, controlled trial of the antiemetic effect of ondansetron on dexmedetomidine-induced emesis in cats.

OBJECTIVE: To determine the effect of ondansetron on the incidence of vomiting in cats pre-medicated with dexmedetomidine and buprenorphine. STUDY DESIGN: Randomized, blinded, controlled trial. ANIMALS: Eighty-nine female domestic shorthair cats, aged 3-60 months (median, 12 months) and weighing 1.2-5.1 kg. METHODS: Each cat received dexmedetomidine (40 µg kg(-1)) plus buprenorphine (20 µg kg(-1)), intramuscularly as pre-anesthetic medication. Cats were assigned to three treatment groups: ondansetron (0.22 mg kg(-1), intramuscular [IM]), either 30 minutes before the pre-anesthetic medication (ONDA group, n = 31) or with the pre-anesthetic medication (OPM group, n = 30) mixed with the pre-anesthetic medications in the same syringe, or not to receive the antiemetic (control group, n = 28). Emesis was recorded as an all-or-none response. The number of episodes of emesis and the time until onset of the first emetic episode were recorded for each cat. Clinical signs of nausea were recorded whenever they occurred, and a numerical rating scale was used to quantify these signs. Data were analyzed using Kruskal-Wallis and Chi-square test; a Bonferroni correction was made for six comparisons; thus, the two-sided p for significance was 0.05/6 = 0.008. RESULTS: There was a significant reduction in the number of cats vomiting, in the episodes of vomiting/cat, the time elapsed between the premedication and the first vomiting and the severity of nausea in the OPM group compared to the ONDA and control groups. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, the administration of ondansetron (0.22 mg kg(-1)) ameliorates and reduced the severity of dexmedetomidine-induced nausea and vomiting only when it was administered in association with this drug.

Biochemical variables in free-ranging white-tailed deer (Odocoileus virginianus) after chemical immobilization in clover traps or via ground-darting.

The objective of this prospective observational cohort study in free-ranging female white-tailed deer (Odocoileus virginianus) was to compare the physiologic effects of two methods of anesthetic drug administration: hand-injection in Clover traps and remote injection by dart after ground-stalking. Six trapped and 14 darted female deer were injected with a median (minimum, maximum) of 590 microg/kg butorphanol (401, 1070 microg/kg), plus 235 microg/kg medetomidine (160, 429 microg/kg) intramuscularly. In the trap, the deer struggled when approached and were restrained for injection. Darted deer sprinted away after injection. Once immobilized, deer were transported to a veterinary hospital where blood was collected and vital signs were measured on admission. Admission data from a subset of deer in which measurements were taken within 40 min of trapping (n = 6) or darting (n = 5) were analyzed. After salpingectomy under isoflurane and while still anesthetized, another blood sample was collected from all 20 deer. Body weight and immobilization drug doses were not different between groups. On admission, most deer from both groups were hypoxemic, although the darted deer were significantly more hypoxemic. The median rectal temperature in trapped deer was higher than in darted deer, and temperatures higher than 39 degrees C only occurred in trapped deer. The median heart rate in trapped deer was more than twice that in darted deer. Trapped deer had lower median pH and base excess; in trapped deer, the median plasma lactate concentration was more than fivefold higher than in darted deer. After surgery, the median serum creatine kinase concentration was nearly 10-fold higher in trapped deer, and the median cardiac troponin I concentration was higher in trapped deer but undetectable in 10 of 14 darted deer. The white-tailed deer immobilized by hand-injection in Clover traps experienced more severe physiologic perturbations than deer remotely injected by dart after ground-stalking. These perturbations might be sufficient to cause myocardial damage.