Ya-Pei Chang

Magnetic resonance imaging of traumatic intervertebral disc extrusion in dogs.

This retrospective study evaluated the magnetic resonance (mr) images of traumatic disc extrusions in 11 dogs. The findings included a reduction in the volume and signal intensity of the nucleus pulposus, focal hyperintensity within the overlying spinal cord on T2-weighted mr images, and subtle spinal cord compression, extraneous material or signal change within the vertebral canal. The largest area of hyperintensity in the spinal cord was directly over or close to the affected disc space, appeared asymmetrical and in the majority of cases was less than one vertebra in length. Parenchymal spinal cord haemorrhage was identified in four of the dogs. Vacuum phenomena, evident as a signal void in the centre of the disc, were identified in two of the dogs. The mr images were distinct from those reported for other causes of spinal cord dysfunction.

Clinical and neurological characteristics of aortic thromboembolism in dogs

OBJECTIVES To characterise the clinical presentation and neurological abnormalities in dogs affected by aortic thromboembolism. METHODS The medical records of 13 dogs diagnosed with aortic thromboembolism as the cause of the clinical signs, and where a complete neurological examination was performed, were reviewed retrospectively. RESULTS The onset was acute in only four dogs, chronic in five dogs (with all of these presenting as exercise intolerance) or chronic with acute deterioration in four dogs. Dogs with an acute onset of clinical signs were more severely affected exhibiting neurological deficits, while dogs with a chronic onset of disease predominantly presented with the exercise intolerance and minimal deficits. The locomotor deficits included exercise intolerance with pelvic limb weakness (five of 13), pelvic limb ataxia (one of 13), monoparesis (two of 13), paraparesis (two of 13), non-ambulatory paraparesis (two of 13) and paraplegia (one of 13). There was an apparent male predisposition and the cavalier King charles spaniel was overrepresented. CLINICAL SIGNIFICANCE The rate of onset of clinical signs appears to segregate dogs affected by aortic thromboembolism into two groups, with different clinical characteristics and outcomes. Dogs with an acute onset of the clinical signs tend to be more severely affected, while dogs with a chronic onset predominantly present with exercise intolerance. It is therefore important to consider aortic thromboembolism as a differential diagnosis in dogs with an acute onset of pelvic limb neurological deficits and in dogs with longer standing exercise intolerance.

Central diabetes insipidus associated with primary focal B cell lymphoma in a dog

CENTRAL diabetes insipidus is an uncommon condition characterised by polyuria due to a deficiency in the secretion of antidiuretic hormone from the posterior pituitary gland. The causes of central diabetes insipidus in dogs include intracranial tumours, such as craniopharyngioma, meningioma,

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.

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 dogs 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.

CASE REPORT: CHOROID PLEXUS CARCINOMA IN THE POSTERIOR CRANIAL FOSSA — PATHOLOGICAL ASSESSMENT AND TREATMENT IN A DOG

Choroid plexus tumors (PTs) are rare in dogs. Herein, we reported a canine case of choroid plexus carcinoma (CPC) and its clinical treatment. A 10-year-old male Shar Pei presented a two-month history of progressive uncoordinated change in head and gait posture. Magnetic resonance imaging (MRI) showed a lesion in posterior cranial fossa characterized by iso- to hypo-intensity in T1 and iso- to hyper-intensity in T2 with a homogeneous contrast uptake. The case received a one-month course of steroid therapy, and then performed by suboccipital craniectomy. The histopathological examination was described as CPC. The neurological symptoms were immediately and significantly improved after surgery. Follow-up MRI demonstrated that approximately 60% of the tumor was resected. To our knowledge, the clinical outcome of CPC was very poor. In this study, we provided an effective surgical approach, suboccipital craniectomy, for CPC in the posterior cranial fossa to avoid excess brain damage.

Application potential of mesenchymal stem cells from euthanased dogs: evaluation of the pathogen transmission risk

THE therapeutic potential of mesenchymal stem cells (MSCs) has gradually gained recognition (Crovace and others 2008, Guercio and others 2012). Due to the scarcity of MSCs (Caplan 2007), ex vivo expansion is necessary to obtain sufficient numbers for clinical applications. For some injuries, stem cell therapy is reported to be more effective when applied in a timely manner (Park and others 2011). Moreover, because histocompatibility matching is not required for MSC application (Kornblit and others 2013), it is increasingly recognised that MSCs could be manufactured as off-the-shelf products for allotransplantation. Currently, bone marrow-derived MSCs (BMSCs) and adipose tissue-derived MSCs are the most prevalent MSCs in clinical trials (Strioga and others 2012). Although MSCs from various sources share many biological features, differences are reported in their immunophenotype, proliferative capacity, differentiation potential and gene expression profile. Consequently, their utility and effectiveness for medical applications may differ. For example, BMSCs in humans, horses and dogs show superior chondrogenic or osteogenic potential to adipose tissue-derived MSCs in vitro (Huang and others 2005, Sakaguchi and others 2005, Vidal and others 2008, Alves and others 2014). The accessibility of the MSC sources may also influence their application. Although carrying minimal risks, BM aspiration is an invasive procedure. In contrast, adipose tissue-derived MSCs can be isolated from adipose tissue removed during lipectomy and liposuction, turning medical waste into a valuable source of MSCs for allotransplantation (Strioga and others 2012). Furthermore, researchers continue to discover alternative sources of MCSs, such as isolating MSCs from the trabecular bones of human patients undergoing hip arthroplasty (Leonardi and others 2008, Coipeau and others 2009). In addition to the abovementioned MSC sources, in veterinary medicine, deceased donors, including euthanased animals from shelters, may be a potential source of MSCs. Nevertheless, determining the donor eligibility of …

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.