Abstract. Although glioblastoma multiforme (GBM), a World Health Organization grade IV astrocytoma, is the most common primary brain tumor in humans, in dogs GBM is relatively rare, accounting for only about 5% of all astrocytomas. This study presents combined clinical, neuroimaging, and neuropathologic findings in five dogs with GBM. The five dogs, aged from 5 to 12 years, were presented with progressive neurologic deficits that subsequent clinical neurologic examination and neuroimaging studies by magnetic resonance imaging (MRI), localized to space occupying lesions in the brain. MRI features of the tumors included consistent peritumoral edema (n ϭ 5), sharp borders (n ϭ 4), ring enhancement (n ϭ 3), heterogenous T2-weighted signal intensity (n ϭ 3), iso-to hypointense T1-weighted images (n ϭ 5), necrosis (n ϭ 5), and cyst formation (n ϭ 2). Two tumors were diagnosed clinically using a computed tomography-guided stereotactic biopsy procedure. At necropsy all the tumors resulted in, on transverse sections, a prominent midline shift and had a variegated appearance due to intratumoral necrosis and hemorrhage. Histologically, they had serpentine necrosis with glial cell pseudopalisading and microvascular proliferation, features which distinguish human GBM from grade III astrocytomas. Immunoreactivity of tumor cells for glial fibrillary acidic protein was strongly positive in all cases, whereas 60% and 40% of the tumors also expressed epidermal growth factor receptor and vascular endothelial growth factor, respectively. These canine GBMs shared many diagnostic neuroimaging, gross, microcopic, and immunoreactivity features similar to those of human GBMs.

The cervical spine of 21 dogs with clinical signs of cervical stenotic myelopathy was evaluated using magnetic resonance (MR) imaging. Spin echo T1, T2 and gradient echo T2 weighted images were obtained with a 1.5 Tesla magnet in 12 dogs and a 1.0 Tesla magnet in 9 dogs. Sagittal or parasagittal T1W and T2W images were helpful in determining the presence of spinal cord compression or degenerative disease of the articular processes. Transverse T1W and T2W images were the most useful for the identification of dorsolateral spinal cord compression secondary to soft tissue and ligament hypertrophy, as well as synovial cysts, associated with the articular processes. The MR imaging findings were consistent with the surgical findings in all 14 dogs that underwent surgery. Magnetic resonance imaging provided a safe, non-invasive method of evaluating the cervical spine in dogs suspected of having cervical stenotic myelopathy. Veterinary

Spinal cord dysfunction secondary to spinal arachnoid cysts (SACs) has been reported previously in dogs. This retrospective study reviews the clinical signs, radiographic findings, and outcome after surgical resection of SACs in 14 dogs. Plain vertebral column radiographs and myelography were done in all dogs. Computed tomography (CT) was done in 7 dogs and magnetic resonance (MR) imaging in 3 dogs. Affected dogs were between 1 and 12 years of age, and 8 of 14 were Rottweilers. Abnormalities detected on neurological examination depended on the location of the SAC. Five dogs had bilobed or multiple SACs. SACs were located in the cervical vertebral column in 11 dogs and in the thoracic vertebral column in 4 dogs. All dogs had dorsally or dorsolaterally located SACs. Two dogs also had additional ventrally located SACs. Spinal cord compression secondary to intervertebral disc extrusion or protrusion was demonstrated at the site of the SACs in 2 dogs. Surgical resection of the SACs was completed in all dogs. Eleven dogs were available for follow-up. Five weeks postoperatively, 7 dogs improved in neurological function, with some residual ataxia and paresis in 6 of these dogs. Neurological function had deteriorated in 4 dogs. It was concluded from this study that Rottweilers have a higher incidence of SACs than other breeds of dog. Furthermore, bilobed or multiple SACs can occur commonly, and myelography effectively localized SACs in dogs. Surgical resection of SACs resulted in improvement in neurological function in the majority of treated dogs.Key words: Canine; Myelogram; Neuroimaging; Rottweiler; Subarachnoid cyst. Spinal arachnoid cysts (SACs) have been reported previously as a cause of neurological dysfunction in dogs and cats. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Although most cysts are thought to be congenital, SACs have been reported in association with spinal cord trauma and intervertebral disc disease.1-10 Thirty-nine cases of SACs have been reported previously. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In the majority of these reports, there was no age, breed, or gender predilection for cyst occurrence. In 1 report, 6 of 11 dogs were Rottweilers. 16 In most dogs, SACs were located dorsal or dorsolateral to the spinal cord, and in 4 dogs, multiple cysts were reported. In 3 dogs, multiple cysts were present at the same location and in another dog the cysts were located at 2 different anatomic sites. 9,16 Two of the dogs with multiple SACs at the same location also had a ventrally located SAC. 16 Of the 39 dogs previously reported, SACs were located only in the cervical vertebral column in 23 dogs, only in the thoracic vertebral column in 15 dogs, and in both the cervical and thoracic vertebral column in 1 dog. Myelography was used to diagnose SACs in all reports. In 9 dogs, computed tomography (CT) was done, and in 4 dogs, magnetic resonance (MR) imaging was done in addition to myelography to further evaluate the location of SACs. Surgical removal of the SAC was performed in 3...

There is a lack of effective means of promoting remyelination of the central nervous system (CNS) in humans with chronic demyelinating disease. We have investigated the ability of transplanted glia to myelinate areas of the CNS equivalent to focal demyelinated lesions in multiple sclerosis (MS). In these studies we show that transplantation of oligodendrocytes or their progenitors into the CNS of a neonatal or adult canine myelin mutant results in repair of large areas similar in size to many MS plaques. Progenitor or pre-progenitor cells of the oligodendrocyte lineage have the greatest capacity for myelination following grafting, although cells of neonatal origin may also be used. Such an approach may therefore have therapeutic value in the repair of focal lesions in human myelin disease.

A 6-year-old neutered female Boston Terrier had a slow onset of blindness and behavior changes. Neurologic abnormalities included bilateral visual loss with absent menace responses and visual tracking, mydriatic pupils, slow pupillary light responses and papilledema. On magnetic resonance imaging (MRI) there were multiple cyst-like structures found in the parenchyma of the cerebrum, cerebellum and brainstem. Histopathologically the diagnosis was a choroid plexus carcinoma with meningeal carcinomatosis. The findings differ from previous descriptions of the MRI characteristics of choroid plexus tumors.

The cervical spine of 27 dogs with cervical pain or cervical myelopathy was evaluated using magnetic resonance imaging (MRI). Spin echo T1, T2, and post-contrast T1 weighted imaging sequences were obtained with a 0.5 Tesla magnet in 5 dogs and a 1.5 Tesla magnet in the remaining 22 dogs. MRI provided for visualization of the entire cervical spine including the vertebral bodies, intervertebral discs, vertebral canal, and spinal cord. Disorders noted included intervertebral disc degeneration and/or protrusion (12 dogs), intradural extramedullary mass lesions (3 dogs), intradural and extradural nerve root tumors (3 dogs), hydromyelia/syringomyelia (1 dog), intramedullary ring enhancing lesions (1 dog), extradural synovial cysts (1 dog), and extradural compressive lesions (3 dogs). The MRI findings were consistent with surgical findings in 18 dogs that underwent surgery. Magnetic resonance imaging provided a safe, useful non-invasive method of evaluating the cervical spinal cord.

Three Mastiffs and 1 Great Dane were presented to the University of Wisconsin Veterinary Medical Teaching Hospital for cervical myelopathy based on history and neurologic examination. All dogs were males and had progressive ataxia and tetraparesis. Degenerative arthritis of the articular facet joints was noted on survey spinal radiographs. Myelography disclosed lateral axial compression of the cervical spinal cord medial to the articular facets. Extradural compressive cystic structures adjacent to articular facets were identified on magnetic resonance imaging (1 dog). High protein concentration was the most important finding on cerebrospinal fluid analysis. Dorsal laminectomies were performed in all dogs for spinal cord decompression and cyst removal. Findings on cytologic examination of the cystic fluid were consistent with synovial fluid, and histopathologic results supported the diagnosis of synovial cysts. All dogs are ambulatory and 3 are asymptomatic after surgery with a follow-up time ranging from 1 to 8 months. This is the 1st report of extradural synovial cysts in dogs, and synovial cysts should be a differential diagnosis for young giant breed dogs with cervical myelopathy.Key words: Magnetic resonance imaging; Myelogram.A lthough extradural synovial cysts have been reported in horses 1-5 and humans, 6-13 they have not been reported in dogs with compressive myelopathy. The most common causes of cervical myelopathy in large or giant breed dogs under 2 years of age are cervical spondylomyelopathy, degenerative disk disease, infectious agents, and trauma. 14 To our knowledge, this is the 1st report of canine cervical extradural synovial cysts. The purpose of this report is to describe the presentation, diagnosis, treatment, and prognosis of giant breed dogs affected with extradural synovial cysts. Case HistoriesThree English Bull Mastiffs and 1 Great Dane were presented to the University of Wisconsin Veterinary Medical Teaching Hospital for evaluation of cervical myelopathy. Signalment and historical and clinical findings are summarized in Table 1. Only dog 3 had previously undergone surgery at another institution, and presented 6 months after partial dorsal laminectomy at C2-C3 (right side) and C6-C7 (left side).All dogs underwent survey spinal radiographs and lumbar myelography with 0.45 mL/kg iohexol (Omnipaque, Micomed, Princeton, NJ) under general anesthesia. Lumbar spinal fluid analysis was obtained in dogs 1, 2, and 3. Magnetic resonance imaging (MRI) was performed on dog 4. Postcontrast MRI imaging was obtained with gadopentate dimeglumine (Magnevist, Berlex, Wayne, NJ). Surgical decompression was achieved 1 day (dog 1), 1 week (dog 4), or 1 month (dogs 2 and 3) after myelography. Dorsal laminectomy was performed in all dogs. Cyst cytology was obtained in dogs 2 and 4, and histopathology was performed in all dogs. ResultsAll but 1 of the affected dogs were English Bull Mastiffs ( age at the time of presentation. The time of onset of clinical signs to presentation was relatively short. All dogs wer...

We have previously shown that oligodendroglial progenitors (OP) can be generated from multipotent rat neural precursor cells. We now report the generation of a homogeneous culture of canine OP from neural precursor cells. In non-adherent cultures, homogeneous OP cultures were obtained in 6-8 weeks of treatment with B104 cell conditioned medium (B104CM). In adherent cultures where astrocytes grew as a layer of substrate, colonies of OP invariably appeared at 10-14 days in vitro (DIV) and the colonies were expanded as free-floating spheres (oligospheres), in the presence of B104CM, suggesting that astrocytes facilitate the generation of canine OP. The oligosphere cells were characterized by self-renewal in the presence of B104CM and by terminal differentiation into oligodendrocytes after withdrawal of B104CM. Transplantation studies indicated that the extensively expanded oligosphere cells retained myelination capacity. The oligospheres thus provide a valuable source for experimental cell therapy studies.