OBJECTIVE To evaluate the efficacy of IV administration of a product containing hyaluronan, sodium chondroitin sulfate, and N-acetyl-d-glucosamine for prevention or treatment of osteoarthritis in horses. ANIMALS 32 healthy 2- to 5-year-old horses. PROCEDURES The study involved 2 portions. To evaluate prophylactic efficacy of the test product, horses received 5 mL of the product (n = 8) or saline (0.9% NaCl) solution (8; placebo) IV every fifth day, starting on day 0 (when osteoarthritis was induced in the middle carpal joint of 1 forelimb) and ending on day 70. To evaluate treatment efficacy, horses received either the product or placebo (n = 8/treatment) on days 16, 23, 30, 37, and 44 after osteoarthritis induction. Clinical, diagnostic imaging, synovial fluid, gross anatomic, and histologic evaluations and other tests were performed. Results of each study portion were compared between treatment groups. RESULTS Limb flexion and radiographic findings were significantly worse for horses that received the test product in the prophylactic efficacy portion than for placebo-treated horses or product-treated horses in the treatment efficacy portion. In the prophylactic efficacy portion, significantly less articular cartilage erosion was identified in product-treated versus placebo-treated horses. In the treatment efficacy portion, joints of product-treated horses had a greater degree of bone edema identified via MRI than did joints of placebo-treated horses but fewer microscopic articular cartilage abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that caution should be used when administering the evaluated product IV to horses, particularly when administering it prophylactically, as it may have no benefit or may even cause harm.

OBJECTIVE To investigate metabolite concentrations of the brains of dogs with intracranial neoplasia or noninfectious meningoencephalitis by use of short echo time, single voxel proton magnetic resonance spectroscopy (1H MRS) at 3.0 T. ANIMALS 29 dogs with intracranial lesions (14 with neoplasia [3 oligodendromas, 3 glioblastomas multiformes, 3 astrocytomas, 2 lymphomas, and 3 meningiomas] and 15 is with noninfectious meningoencephalitis) and 10 healthy control dogs. PROCEDURES Short echo time, single voxel 1H-MRS at 3.0 T was performed on neoplastic and noninfectious inflammatory intracranial lesions identified with conventional MRI. Metabolites of interest included N-acetyl aspartate (NAA), total choline, creatine, myoinositol, the glutamine-glutamate complex (Glx), glutathione, taurine, lactate, and lipids. Data were analyzed with postprocessing fitting algorithm software. Metabolite concentrations relative to brain water content were calculated and compared with results for the healthy control dogs, which had been previously evaluated with the same 1H MRS technique. RESULTS NAA, creatine, and Glx concentrations were reduced in the brains of dogs with neoplasia and noninfectious meningoencephalitis, whereas choline concentration was increased. Concentrations of these metabolites differed significantly between dogs with neoplasia and dogs with noninfectious meningoencephalitis. Concentrations of NAA, creatine, and Glx were significantly lower in dogs with neoplasia, whereas the concentration of choline was significantly higher in dogs with neoplasia. Lipids were predominantly found in dogs with high-grade intra-axial neoplasia, meningioma, and necrotizing meningoencephalitis. A high concentration of taurine was found in 10 of 15 dogs with noninfectious meningoencephalitis. CONCLUSIONS AND CLINICAL RELEVANCE 1H MRS provided additional metabolic information about intracranial neoplasia and noninfectious meningoencephalitis in dogs.

OBJECTIVE To compare the orthogonal diameter (visual metric) method against a manual perimeter tracing (planimetry) method to measure volume of brain tumors in dogs by use of MRI scans. SAMPLE 22 sets of MRI brain scans pertaining to 22 client-owned dogs with histologically confirmed glioma. PROCEDURES MRI scans were reviewed by 2 operators, and scans revealing tumors with a degree of gadolinium enhancement that allowed discrimination between tumor tissue and healthy parenchyma were used. Each operator calculated tumor volume for each set of scans twice by use of visual metric and planimetry methods. Inter- and intraoperator variability were assessed by calculation of an agreement index (AI). RESULTS Mean ± SD intraoperator AIs were 0.79 ± 0.24 for the visual metric method and 0.89 ± 0.17 for the planimetry method. Intraoperator variability for both operators was significantly less when the planimetry method was used than when the visual metric method was used. No significant differences were identified in mean interoperator AI between visual metric (0.68 ± 0.28) and planimetry (0.67 ± 0.31) methods. CONCLUSIONS AND CLINICAL RELEVANCE The lower intraoperator variability achieved with the planimetry versus visual metric method should result in more precise volume assessments when the same operator performs multiple volume measurements of brain tumors in dogs. Equivocal results for interoperator variability may have been due to method variance or inadequate preliminary training. Additional studies are needed to evaluate the suitability of planimetry for assessing response to treatment.

OBJECTIVE To describe the perfusion and diffusion characteristics of the liver in healthy dogs as determined by morphological, perfusion-weighted, and diffusion-weighted MRI. ANIMALS 11 healthy adult Beagles. PROCEDURES Each dog was anesthetized and underwent morphological, perfusion-weighted, and diffusion-weighted MRI of the cranial aspect of the abdomen. On the MRI images, a region of interest (ROI) was established for each of 6 structures (aorta, caudal vena cava, portal vein, hepatic parenchyma, splenic parenchyma, and skeletal [epaxial] muscle). The signal intensity was determined, and a time-intensity curve was generated for each ROI. The apparent diffusion coefficient (ADC) was calculated for the hepatic and splenic parenchyma in diffusion-weighted MRI images, and the normalized ADC for the liver was calculated as the ratio of the ADC for the hepatic parenchyma to the ADC for the splenic parenchyma. Dogs also underwent abdominal ultrasonography, and ultrasound-guided fine-needle aspirate samples and biopsy specimens were obtained from the liver for cytologic and histologic examination. RESULTS Cytologic and histologic results suggested that the liver was clinically normal in all dogs. Perfusion-weighted MRI parameters varied among the 6 ROIs. The mean ± SD ADC of the hepatic parenchyma was 0.84 × 10(−3) mm2/s ± 0.17 × 10(−3) mm2/s, and the mean normalized ADC for the liver was 1.8 ± 0.4. CONCLUSIONS AND CLINICAL RELEVANCE Results provided preliminary baseline information about the diffusion and perfusion characteristics of the liver in healthy dogs. Additional studies on dogs of various breeds with and without hepatopathies are necessary to validate and refine these findings.

OBJECTIVE To evaluate the usefulness of autologous bone marrow–derived mesenchymal stem cell (BM-MSC) therapy for the treatment of dogs with experimentally induced acute kidney injury. ANIMALS 6 healthy dogs. PROCEDURES After induction of kidney injury (day 0) with cisplatin (5 mg/kg, IV), dogs immediately received saline (0.9% NaCl) solution (10 mL; n = 3) or BM-MSCs (1 × 106 cells/kg in 10 mL of saline solution; 3) IV. A CBC, serum biochemical analysis, and urinalysis were performed for each dog before administration of cisplatin and on days 1 through 4. Glomerular filtration rate was determined for all dogs on days −7 and 2; BM-MSC tracking by MRI was performed on BM-MSC–treated dogs on days −14 and 4. After sample collection and BM-MSC tracking on day 4, all dogs were euthanized; kidney tissue samples underwent histologic evaluation, immunohistochemical analysis, and cytokine profiling via reverse transcriptase PCR assays. RESULTS Kidney tissue from both groups had mononuclear inflammatory cell infiltration, tubular necrosis, dilated tubules, and glomerular damage. However, there was less fibrotic change and increased proliferation of renal tubular epithelial cells in the BM-MSC-treated dogs, compared with findings for the control dogs. Expressions of tumor necrosis factor-α and transforming growth factor-β were lower in the BM-MSC-treated group, compared with findings for the control group. Laboratory data revealed no improvement in the renal function in BM-MSC-treated dogs. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study suggested that autologous BM-MSCs may accelerate renal regeneration after experimentally induced acute kidney injury in dogs.

OBJECTIVE To determine values of perfusion parameters determined via MRI in the brains of healthy dogs. ANIMALS 10 healthy adult Beagles. PROCEDURES Each dog was anesthetized for MRI examination of the brain, including standard sequences and a perfusion-weighted sequence. Gadoteric acid (0.2 mmol/kg) was injected IV at a rate of 5 mL/s. A dedicated workstation was used to measure the times from contrast medium injection to arrival at an ROI (TO) and peak contrast enhancement (TTP), mean contrast medium transport time (MTT), and cerebral blood flow (CBF) in the caudate nucleus, thalamus, piriform lobe, hippocampus, semioval center, and temporal cerebral cortex. A simple mathematical model was used to compare parameter values among the various brain regions. RESULTS T0 and time to peak contrast enhancement had a significant linear relationship. A significant negative correlation was identified between T0 and CBF and, to a lesser extent, between MTT and CBF. Differences among brain regions were significant for MTT and CBF. The CBF was lowest in the semioval center, and the piriform lobe had almost 2-fold the CBF of that region. No significant differences were identified between hemispheres of the brain. CONCLUSIONS AND CLINICAL RELEVANCE Findings obtained in this study involving healthy dogs may serve as a reference for MRI perfusion measurements in specific brain regions and may help in the characterization of various brain diseases in dogs.