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OBJECTIVE: To evaluate the effects of nanoparticle hyperthermia therapy on monocyte function and tumor-derived factors associated with macrophage polarization in a murine osteosarcoma model. STUDY DESIGN: Experimental study. ANIMALS: Female C3H mice. METHODS: Peripheral blood monocyte cell surface phenotype, monocyte chemotaxis, tumor messenger RNA expression, and survival were compared among osteosarcoma (OS)-bearing mice treated with nanoparticle hyperthermia therapy, OS-bearing mice with osteomyelitis, OS-bearing mice, vehicle control mice, and normal control mice. RESULTS: OS-bearing mice with osteomyelitis had a higher proportion of “nonclassical” monocytes (Ly6C(lo)) compared with all other experimental groups. There were alterations in monocyte expression of multiple chemokine receptors among experimental groups including CXCR2, CCR2, and CXCR4. Monocytes from OS-bearing mice treated with hyperthermia therapy exhibited greater chemotaxis compared with monocytes from OS-bearing mice with osteomyelitis. CONCLUSION: OS likely induced alterations in monocyte phenotype and function. Nanoparticle hyperthermia therapy increased in vitro monocyte chemotaxis. CLINICAL IMPACT: Enhancing monocyte/macrophage function in dogs with OS may enhance antitumor immunity.

To compare the mechanical properties of feline ilial fractures stabilized with either a plate (P), or a plate and IM pin (P + P).Mechanical study.Cadaveric cat pelvii (n = 10).Feline ilial fractures (n = 20) stabilized with either P or P + P were subjected to 100 nondestructive load cycles, then loaded to failure. Deformation after cycling, yield load and displacement, stiffness and load at 2 mm of displacement were compared between groups.There were no significant differences between groups for any of the parameters. Variability of data was much larger for the P + P group.No biomechanical advantage was demonstrated. The P + P constructs were not significantly stronger than plates alone in this acutely loaded cadaveric model.

To compare von Frey mechanical quantitative sensory thresholds (mQSTvF ) between pelvic limbs in dogs before unilateral total hip replacement (THR) surgery; to correlate ground reaction forces (GRF) with mQSTvF ; to assess changes in mQSTvF after THR surgery.Prospective clinical study.Dogs (n = 44).mQSTvF and GRF measured using a pressure sensitive walkway were evaluated before, and 3, 6, and 12 months after, unilateral THR. Measurements were recorded from the affected (operated) pelvic limb (APL) and the non-operated pelvic limb (NPL). Random effects analysis and forwards stepwise linear regression models were used to evaluate the influence of time since surgery and patient factors on mQSTvF thresholds.There were no significant correlations between mQSTvF data and age, bodyweight or the GRF variables. Preoperative mQSTvF measured at the APL and NPL did not differ (P = .909). mQSTvF thresholds increased significantly after 12 months in NPL (P = .047) and APL (P = .001). In addition to time, APL mQSTvF values were significantly affected by sex (higher in males, P = .010) and body condition score (higher in leaner dogs, P = .035) and NPL mQSTvF values by sex (P = .038).Successful unilateral THR results in decreased central sensitization after 12 months.

To perform algometric readings in normal dogs in a design that would assess possible confounding factors.Prospective study.Skeletally mature spayed female, intact male and castrated male retriever or retriever mix dogs without orthopedic or neurologic disease (n = 19).Twelve common surgical sites were selected for algometric pressure testing. Threshold response was defined as a conscious recognition of the stimulus, and recorded in Newtons. Sites were tested in the same order, and the testing sequence repeated 3 times on each side of the dog. Dogs were tested in the morning and evening of the same day and was repeated 10-14 days later, allowing 4 separate data collections for each dog.Data were analyzed using ANOVA or ANCOVA. When all the data were included in the analysis, dog (P.0001), order (P.0001), site (P.0001), site order (P = .0217), time (P.0001), day (P.0001) and repetition (P.0001) all significantly affected the algometer readings. When only the first reading for each site was included in the analysis, dog (P.0001), site (P.0001) and sex (P .0001) all significantly affected algometer readings.These results suggest that learning occurred over repeated collection time points, with dogs anticipating the stimulus and reacting at lower thresholds.

To determine whether there is a difference between the ability of peak vertical force (PVF), vertical impulse (VI), and percentage body weight distribution (%BW(dist) ) in differentiating which leg is most affected by hip joint pain before total hip replacement (THR) surgery, and for measuring changes in limb use after THR surgery.Prospective clinical study.Dogs (n = 47).Ground reaction force (GRF) data were collected using a pressure-sensitive walkway the day before THR surgery and at ∼3, 6, and 12 months postoperatively. PVF and VI expressed as a percentage of body weight (%PVF, %VI), and %BW(dist) were recorded. Regression models performed separately for each outcome were used for statistical analysis.When comparing limb use between the affected limb (AP) and the nonaffected limb (NP) preoperatively, differences between limbs were statistically significant when evaluated using PVF (P = .023), VI (P = .010), and %BW(dist) (P = .012). When evaluating the magnitude of absolute and percentage change difference in AP limb use preoperatively versus postoperatively, differences were statistically significant when evaluated using PVF (P.001 and P = .001, respectively), VI (P = .001 and P.001) and %BW(dist) (P.001 and P.001).There appeared to be no difference in the sensitivity of VI, PVF, and %BW(dist) for evaluating limb use before and after THR.

To evaluate a technique for midhumeral peripheral nerve blockade in the dog.Cadaveric technique development; in vivo placebo-controlled, prospective crossover study.Canine cadavers (n=38) and 8 clinically healthy, adult hound dogs.A technique for peripheral block of the radial, ulnar, musculocutaneous, and median nerves (RUMM block) was evaluated using cadaver limbs. Eight purpose-bred, research dogs were anesthetized; a RUMM block was performed on each thoracic limb. One limb from each dog randomly received 0.5% bupivacaine and the opposite limb was assigned to receive sterile saline solution as a control. After recovery from anesthesia, skin sensation at selected dermatomes was evaluated for 24 hours using a mechanical stimulus. Weight-bearing, conscious proprioception, and withdrawal reflex were also evaluated. One month after initial testing, each dog was reanesthetized and each limb received the opposite treatment.Sensory thresholds were significantly increased over baseline measurements when compared with control limbs for all nerves. Complete sensory block was achieved in radial (15/16), ulnar (3/16), musculocutaneous (8/16), and median (11/16) nerves, using a mechanical stimulus of analgesia. Complete simultaneous block of all nerves was only obtained in 1 of 16 limbs.RUMM block resulted in desensitization of the skin in the associated dermatomes for 4-10 hours. Complete sensory block of the dermatomes supplied by the radial nerve was most consistent.RUMM block may be an effective technique to provide adjunctive analgesia for dogs undergoing surgery of the distal aspect of the thoracic limb.

To determine the prevalence of radiographic signs of degenerative joint disease (DJD) in a randomly selected sample of domestic cats.Prospective observational study.Client-owned cats.Cats (n=100) from a single practice and equally distributed across 4 age groups (0-5; 5-10; 10-15, and 15-20 years old) were randomly selected (regardless of heath status) and sedated for orthogonal radiographic projections of all joints and the spine. Quasi-Poisson regression analysis was used to investigate the relationship between patient demographics, blood biochemistry, hematologic and urine analysis variables, and DJD severity.Most (92%) cats had radiographic evidence of DJD; 91% had at least 1 site of appendicular DJD and 55% hador = 1 site of axial column DJD. Affected joints in descending order of frequency were hip, stifle, tarsus, and elbow. The thoracic segment of the spine was more frequently affected than the lumbosacral segment. Although many variables were significantly associated with DJD, when variables were combined, only the association between age and DJD was significant (P.0001). For each 1-year increase in cat age, the expected total DJD score increases by an estimated 13.6% (95% confidence interval: 10.6%, 16.8%).Radiographically visible DJD is very common in domesticated cats, even in young animals and is strongly associated with age.DJD is a common disease of domesticated cats that requires further investigation of its associated clinical signs.

To (1) determine prevalence of radiographically detectable meniscal mineralization in domestic cats and (2) to evaluate the association between meniscal mineralization and degenerative joint disease (DJD).Prospective study.Client-owned cats (n=100) and 30 feline cadavers.Randomly selected client-owned cats were used to determine the prevalence of meniscal mineralization. Stifles from feline cadavers were used to evaluate the relationship between meniscal mineralization (using high-resolution X-ray), radiographic DJD, and cartilage damage. Menisci were evaluated histologically.Forty-six percent of the client-owned cats had meniscal mineralization detected in 1 or both stifles. Pain scores were not significantly different between stifles with meniscal mineralization and those with no radiographic pathology (P=.38). Thirty-four of 57 cadaver stifles had meniscal mineralization, which was always located in the cranial horn of the medial meniscus. Percentage mineralization of the menisci was significantly correlated with the cartilage damage score of the medial femoral (r(2)=0.6; P.0001) and tibial (r(2)=0.5; P.0001) condyles as well as with the total joint cartilage damage (r(2)=0.36; P.0001) score and DJD score (r(2)=0.8; P.0001).Meniscal mineralization is a common condition in domestic cats and seems to indicate medial compartment DJD.Clinical significance of meniscal mineralization is uncertain. Further work is needed to determine if the meniscal mineralization is a cause, or a consequence of joint degeneration.

Objective— To evaluate extracorporeal intraoperative radiation therapy (IORT) as a treatment method for limb and joint sparing in dogs with appendicular sarcomas in sites other than the distal aspect of the radius. Study Design— Retrospective study. Animals— Thirteen client-owned dogs. Methods— The bone tumor database and medical records (1998–2002) were reviewed for dogs with primary appendicular bone tumors treated with IORT limb-sparing surgery and adjuvant chemotherapy. The segment of bone containing the tumor was isolated from adjacent soft tissue and an osteotomy performed distant to the tumor. The bone segment was exteriorized, irradiated (70 Gy single fraction), and then stabilized with internal fixation. Adjuvant chemotherapy was administered. Lameness was graded and local and distant tumor control was determined. Associations between intra- and postoperative variables with complications and Kaplan–Meier survival analysis for median disease-free interval and survival time were calculated. Results— Limb function was good or excellent in 10 dogs (77%). Postoperative complications (9 dogs, 69%) included deep infection, fracture of the irradiated bone, and implant failure. Surgical failure was more likely if a single implant was used to stabilize the osteotomized bone and if deep infection developed postoperatively. In 3 dogs, tumors recurred locally within bone in the radiation field. The disease-free and overall success rates of extracorporeal IORT for limb and joint preservation were 46% and 54%, respectively. Conclusions— Extracorporeal IORT provides a novel alternative to traditional techniques for preservation of joint and limb function in dogs with primary appendicular sarcomas. A minimum of 2 implants and intramedullary bone cement should be used to stabilize the osteotomized bone to minimize postoperative complications. Extracorporeal IORT should be used with caution in dogs with tumors of the distal tibia because of a high complication rate. Dogs with tumors in areas of good soft-tissue coverage, such as the humerus and femur, may be good candidates for limb and joint-sparing surgery using extracorporeal IORT. Clinical Relevance— Extracorporeal IORT is a surgical technique that can be used for limb and joint salvage in dogs with primary appendicular sarcomas in sites usually not amenable to traditional limb-sparing techniques.

OBJECTIVE To assess the results of an omental pedicle graft in combination with a thoracodorsal axial pattern flap for the reconstruction of chronic nonhealing axillary wounds in 10 cats caused by forelimb entrapment within a collar. STUDY DESIGN A prospective, clinical trial. ANIMALS USED: Ten client-owned domestic shorthair cats. METHODS Routine biochemical and hematologic evaluation was performed on each cat, and all were tested for feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV). Microbial culture was performed on samples from the wounds. After surgical debridement, omentalization using a vascular pedicle of greater omentum, and closure of the chronic axillary wounds, using a thoracodorsal axial pattern flap, was performed. All excised tissue was examined histologically. RESULTS The sex distribution was 7 males and 3 females, with a mean age of 3.5 years. The cats had undergone a median number of 3 previous repair attempts over a 1.5- to 25-month period before referral (mean, 10.2 months). No hematologic or biochemical abnormalities were noted apart from moderately elevated creatine kinase and aspartate transaminase concentrations in some cats. All cats were negative for FIV and FeLV. Histologic examination of resected tissue revealed hair (foreign body) in 2 cats and an unidentified foreign-body reaction in 3 other cats. Complete healing occurred in all cats (mean follow-up period of 21.7 months), with 2 cats requiring further surgery: 1 for flap dehiscence at 4 days after surgery, and 1 for donor-site dehiscence at 4 days after surgery. One other cat developed a large seroma in the axilla that resolved by 10 days following surgery. CONCLUSION The use of an omental pedicle graft in combination with a thoracodorsal axial pattern flap is the first consistently successful 1-step technique for the management of chronic nonhealing axillary wounds in cats.