Long-term outcomes and prognostic factors in dogs with meningoencephalitis of unknown origin and suspected necrotic lesions on magnetic resonance imaging: 37 cases (2007-2020).

OBJECTIVE: To describe the long-term outcomes, overall survival, progression-free survival, and prognostic factors in dogs with necrotizing encephalitis (NE). ANIMALS: 37 client-owned dogs clinically diagnosed with NE. METHODS: All dogs underwent MRI and CSF analysis. Cox proportional hazards regression was used to examine factors related to the risk of relapse and death, including signalment, history, diagnostic investigation results, and treatments before the first relapse. RESULTS: The medians of the overall and progression-free survival times were 639 days (IQR, 342 to 1,482 days) and 233 days (IQR, 111 to 775 days), respectively. Overall survival was highly correlated with progression-free survival. Four dogs (11%) died or were euthanized within 3 months of diagnosis. Relapse within 6 months was associated with a shorter overall survival. However, no prognostic factors for overall survival were found. The category of patients with presenting clinical signs that lasted 29 days to 6 months (OR, 3.26; 95% CI, 1.35 to 7.90) was associated with a higher risk of relapse. Seizures were presented in 75.7% of dogs, with a recurrence rate of 100%. CLINICAL RELEVANCE: This report provides comprehensive follow-up information for dogs with NE, revealing a fair prognosis and low early mortality rate. Seizure is a very common clinical sign with a high recurrence rate.

Outcomes in Dogs with Multiple Sites of Cervical Intervertebral Disc Disease Treated with Single Ventral Slot Decompression.

In dogs with acute myelopathy but showing multiple sites of spinal compression from intervertebral disc disease (IVDD) on imaging, one approach is surgical decompression of the single acute disc extrusion while ignoring other previously extruded or protruded discs. However, little is known regarding the outcomes of this approach. This study described the outcomes and investigated prognostic factors in 40 dogs with multiple sites of cervical disc extrusion or protrusion on MRI who underwent ventral slot decompression for the single acute disc. The overall recovery rate was 97.5%. The median recovery time was seven days. The number of affected discs (including disc extrusion and protrusion) and the presence and number of the affected discs causing severe spinal compression did not influence the 30-day outcome. Compared with 23 dogs with single disc extrusion treated surgically, the recovery time and outcomes were similar between the two groups. The total number of affected discs was not associated with recovery time or outcomes. In conclusion, if an acute disc could be identified, ventral slot decompression targeting the single acute disc is a viable management approach for dogs with an acute presentation but diagnosed with multiple sites of spinal cord compression from IVDD.

Feasibility and Validity of Postural Reaction Tests in the Neurological Examination in Healthy Rabbits.

Neurological examination remains a fundamental step in the care of patients with neurological disorders. However, studies evaluating the feasibility and validity of neurological examination in rabbits are limited. In this study, postural reaction tests or methods commonly performed in dogs and cats were evaluated in clinically healthy rabbits, and we aimed to postulate a simplified examination list according to the results. The feasibility and validity of each test were determined and screened using a cut-off value of 90%. For the remaining tests/methods, the response rates of tests with similar neuroanatomical pathways were compared. Among the 34 healthy rabbits tested, one method of the hopping reaction (holding then lowering the rabbit quickly towards the floor with only the tested limb touching the ground), the hemi-walking test, the wheelbarrowing test, and the righting response yielded a feasibility and validity of over 90%. When comparing tests/methods with similar neuroanatomical pathways, the normal response rate of the hopping reaction was comparable to that of the hemi-walking test. We conclude that in healthy rabbits, hopping reaction tests using the method mentioned above, hemi-walking, wheelbarrowing, and righting responses are likely to be feasible postural reaction tests that yield consistent and normal responses.

Assessment of the cutaneous trunci muscle reflex in healthy cats: comparison of results acquired by clinicians and cat owners.

OBJECTIVES: The study aimed to evaluate the cutaneous trunci muscle reflex (CTMR) in healthy cats using methods performed by the clinician and the cat's owner at home. METHODS: A total of 55 healthy cats without neurological abnormalities were included in this study. CTMR evaluation was performed sequentially in each cat using three methods by a clinician: method A, pinch skin with a straight 14 cm Crile haemostat forceps; method B, displace fur with the tip of a pen or haemostat forceps; and method C, poke skin with the tip of a straightened paper clip. The normal response rates for each method were obtained and compared. A 'CTMR performance score' was assigned for each cat, reflecting the presence of a normal CTMR response using one or more of the three methods. An 'owner performance score' was also obtained, reflecting the response of the CTMR when performed at home by the cat owner. The two scores were compared as paired data for each cat. RESULTS: The CTMR was elicited normally in 17 (31%), 27 (49%) and 16 (29%) cats using methods A, B and C, respectively. Method B delivered a significantly higher percentage of normal responses. When comparing the 'CTMR performance score' and 'owner performance score', the percentage of normal responses was 60% and 100%, respectively, which was significantly different. CONCLUSIONS AND RELEVANCE: The overall normal response rate of the CTMR in healthy feline subjects was low when performed by a clinician, regardless of the method applied. Conversely, a high percentage of normal responses was obtained by cat owners performing CTMR at home, potentially indicating the impact of stress on the CTMR performance.

Diagnosis of meningeal melanomatosis in a dog using magnetic resonance imaging and cerebrospinal fluid findings.

A 13-year-old spayed female Labrador Retriever was presented with severe progressive tetraparesis. The neuroanatomic localization was the C1-C5 spinal cord segments with brainstem or cranial nerve involvement. Magnetic resonance imaging revealed diffuse T1-weighted and T2-weighted hyperintense lesions with strong contrast enhancement spreading through meninges of the cervical spinal cord and the brain. Few small round areas showing T1-weighted hyperintensity and T2-weighted hypointensity were scattered within the lesions. Cerebrospinal fluid analysis revealed neoplastic round cells and possible melanocytes. Malignant melanoma was suspected. At necropsy, the brain and the entire spinal cord were covered with thick, dark membranous tissue. Based on histopathologic findings, a positive response against Melan-A, and no melanoma identified outside the central nervous system, primary meningeal melanomatosis was diagnosed.

Topical application of Heparanase-1 facilitates bone remodeling during the healing of bone defects in a mouse model.

BACKGROUND: Although previous studies have suggested a stimulatory role of heparanase in physiological bone turnover, the potential therapeutic role of heparanase in bone healing has not been elucidated. The purpose of this study was to assess the effect of topical application of heparanase-1 on bone healing. METHODS: Two different dosages of recombinant mouse heparanase-1 and vehicle control were prepared and delivered via an osmotic pump to provide continuous topical infusion of the therapeutic reagent in a mouse bone defect model at the distal femoral metaphysis. The bone healing progress was evaluated by micro-computed tomography and histological examination at 7, 14, and 21 days after the bone defect was created. RESULTS: The peak of trabecular bone generation was achieved earlier than anticipated with the use of heparanase as measured by medullary bone volume fraction and trabecular number observed in micro-computed tomography, while the remodeling of trabecular bone to cortical bone was also achieved earlier than anticipated with the use of heparanase as measured by connectivity density. Histopathological observation revealed a higher frequency of the presence of cartilaginous tissue in the heparanase-treated groups. Both bone mineral density and cortical bone volume fraction showed the best healing outcome with low-dose heparanase, implying a biphasic effect of its mode of action. CONCLUSION: These results indicated that with the appropriate dose of topical heparanase-1, the progress of bone healing could be accelerated in vivo.

Biomechanical Comparison between Preloaded Position Screw and Lag Screw Fixations for Their Compressive Effects in a Porcine Rib Fracture Model.

OBJECTIVES: The aim of this study was to compare the compressive effect between preloaded position screws and lag screws in fracture fixation. METHODS: Pairs of semi-cylindrical bone fragments were created on a porcine rib model to simulate fractured bones. The compressive forces of fracture fixation generated by preloaded position screws (P group) and conventional lag screws (L group) were recorded by a film stress sensor. In the P group, a pair of Angus bone holding forceps was used to compress the interfragmentary interface until reaching the preloading force of 1.3 MPa. Similar preloading procedure was applied on lag screw fixations to explore its potential of additional compressive force. RESULTS: With 1.3 MPa preloading force and 0.2 Nm screw insertion torque force, the interfragmentary compressive force of P group was similar to that of L group. When the insertion torque force was increased to 0.4 Nm, all screws in the L group failed due to thread stripping. When screws in the P group were installed under 0.4 Nm torque and in the L group under 0.2 Nm torque, the P group generated significantly greater compressive force. With preloading device applied on lag screw installation, it did not further increase the interfragmentary compressive force. CLINICAL SIGNIFICANCE: Compared with lag screws, preloaded position screws tolerated greater torque in screw installation and provided greater interfragmentary compressive force. The study suggests the applicability of preloaded position screws in fracture fixation requiring interfragmentary compression.

Outbreak of thiamine deficiency in cats associated with the feeding of defective dry food.

Objectives The objective of this study was to determine disease progression, association between neurological signs and magnetic resonance imaging (MRI) findings, and long-term outcome in feline thiamine deficiency associated with defective dry food. Methods The clinical records of 17 cats diagnosed with thiamine deficiency related to a defective dry food were examined and data collected. The thiamine level in the food was analysed by liquid chromatography-tandem mass spectrometry. Results The thiamine level in the food was below the recommendation of the National Research Council. Fifteen cats were fed the food exclusively. Prior to the acute development of neurological signs, most cats displayed non-specific signs such as anorexia, lethargy or vomiting. Vestibular signs of varying severity were observed in 94% of the cats, and all but one of these presented with bilateral dysfunction. Other main neurological signs included altered mentation (76%), blindness (59%) and seizures (59%). Moreover, 80% of the cats with seizures presented with cluster seizures or status epilepticus. MRI abnormalities consistent with findings reported in the previous literature were detected in five cases. MRI was unremarkable in one cat with ongoing severe neurological signs even though thiamine had been administered. Most surviving cats recovered rapidly within 2 weeks of treatment and had either returned to normal or had minimal neurological signs at the 2 month follow-up. One cat recovered slowly over 6 months. Most cats with seizures in the initial stage of the disease remained seizure free at the 24 month follow-up. Conclusions and relevance This study documented the association between feline thiamine deficiency and defective dry food. MRI examination provided valuable information in the diagnosis. However, normal MRI findings do not exclude the diagnosis of feline thiamine deficiency, especially once thiamine has been supplemented. MRI findings also may not always reflect the neurological status or severity. If treated promptly, most cats will recover rapidly with a good outcome. Occasionally, recovery may be slow and take several months.

Cerebral Ventriculitis Associated with Otogenic Meningoencephalitis in a Dog.

A dog was evaluated for rapidly progressive mentation change, ataxia, and tetraparesis. The dog's neurological status deteriorated drastically. It became comatose with bilateral mydriasis, and the pupillary light reflex was absent. An anti-inflammatory dose of methylprednisolone was administered, and temporary stabilization of neurological status was achieved. MRI findings were suggestive of ventriculitis and meningoencephalitis originating from the left tympanic cavity. A gadolinium leakage phenomenon was noted, likely resulting from severe damage to the blood-cerebrospinal fluid barrier during the inflammatory process. Analysis of the cerebrospinal fluid and materials in the left tympanic cavity further confirmed the diagnosis. Following surgical and antibiotic treatment, the dog recovered well with only a mild residual head tilt. Seven months after surgery, the dog had a recurrent infection of the left tympanic cavity without intracranial involvement. A second surgery led to an uneventful recovery, and the dog was clinically normal except for a mild head tilt 3 yr after the initial presentation. This is the first report describing ventriculitis associated with otogenic meningoencephalitis in dogs and a gadolinium leakage phenomenon displayed on MRI. The long-term outcome of ventriculitis-complicated otogenic meningoencephalitis in dogs could be satisfied with prompt diagnosis and treatment.

The canine epiphyseal-derived mesenchymal stem cells are comparable to bone marrow derived-mesenchymal stem cells.

Mesenchymal stem cells (MSCs) hold great potential in cell therapy and have attracted increasing interests in a wide range of biomedical sciences. However, the scarcity of MSCs and the prolonged isolation procedure limited the clinical application. To address these 2 issues, we developed a method to isolate MSCs from bone biopsy tissues of euthanized canine body donors. Compared to the traditional method to isolate MSCs from aspirated bone marrow (BMSCs), the isolation procedure for MSCs from harvested epiphyseal cancellous bone (EMSCs) was less time-consuming. The isolated EMSCs had similar plastic-adherence, tri-lineage differentiation and consistent surface marker profiles compared to BMSCs. We harvested BMSCs and EMSCs from 24 euthanized cases from clinics and 42 euthanized donors from a local shelter. The successful rate for EMSC isolation is significantly higher compared to BMSC isolation, while the other properties of the isolated MSCs including the clonogenicity, proliferative potentials and molecular phenotypes were not discernibly different between the MSCs established by the two methods. In conclusion, we demonstrated a new procedure to harvest MSCs by bone biopsy at the epiphyseal region. This method is less time consuming and more reliable, and the resulting MSCs are comparable to those harvested by bone marrow aspiration. The combination of the two methods can greatly improve the efficiency to harvest MSCs.

Protective effect against focal cerebral ischemia injury in acute phase of a novel invasive device for regional hypothermia.

BACKGROUND: Systemic hypothermia is considered beneficial to stroke patients. However, many complications ensue. The aim of this study was to evaluate the effect of a new invasive regional cooling device in cerebral ischemic injury in a rat model. METHODS: After a pilot study confirming the efficiency of the cooling device, 15 adult male Sprague-Dawley rats, weighing 300-400 g, were randomly assigned into three groups: cooling device applied at 14°C and at 26°C, and a sham group. Focal cerebral ischemic injury was achieved by electrocauterization of the left middle cerebral artery through craniectomy and temporal occlusion of both common carotid arteries for 3 hours. Within 30 minutes after the end of ischemic injury, the cooling device was inserted into the rat brain through a stereotactic frame to provide regional hypothermia for 2 hours. The rats were sacrificed immediately after the 2-hour regional hypothermia. RESULTS: Although triphenyltetrazolium chloride staining showed smaller ischemic lesions in both the 26°C and 14°C groups compared to the control group, Fluoro Jade C staining showed no neuroprotective effects in the rostrum cerebral cortex in both groups. However, both triphenyltetrazolium chloride and Fluoro Jade C staining indicated significant beneficial effects in the caudal cerebral cortex in rats with cooling device applied at 26°C compared to the 14°C and control groups. CONCLUSION: Our findings indicated that the device can effectively achieve regional hypothermia and could be beneficial for patients with cerebral ischemia during the acute phase.

Meningothelial meningioma in a Malayan sun bear (Helarctos malayanus).

A 24-year-old, spayed female Malayan sun bear (Helarctos malayanus) in the Taipei Zoo (Taipei, Taiwan) showed clinical signs of slowly progressive anorexia, dullness, compulsive pacing, and circling. The animal subsequently developed acute severe stupor and persistent recumbency. Postcontrast study of computed tomography revealed a spheroid, extra-axial mass with strong but heterogeneous hyperattenuation in the left temporal lobe of the cerebrum. At necropsy, a solitary, well-circumscribed intracranial mass measuring 3 cm × 2.5 cm × 2 cm was attached to the left pyriform lobe with compression of the adjacent neuroparenchyma. Cytological examination obtained from the mass revealed large clumps and sheets of cohesive polyhedral cells with round nuclei, wispy cytoplasm, and indistinct cell borders. Microscopically, the mass was composed of densely packed round to polygonal cells arranged in lobules and small nests. Psammoma bodies, xanthomatous change, and cholesterol deposition were also noted. Immunohistochemical staining of the tumor was positive for vimentin, pancytokeratin, cytokeratin (CK)34BE12, neuron-specific enolase, and epithelial membrane antigen, but negative for glial fibrillary acidic protein and S100 protein. The cytological, histological, and immunohistochemical features were compatible with a meningothelial meningioma.