A. Jaggy

Weanling piglet cerebellum: a surrogate for tolerance to MRT (microbeam radiation therapy) in pediatric neuro-oncology

The cerebellum of the weanling piglet (Yorkshire) was used as a surrogate for the radiosensitive human infant cerebellum in a Swiss-led program of experimental microbeam radiation therapy (MRT) at the ESRF. Five weanlings in a 47 day old litter of seven, and eight weanlings in a 40 day old litter of eleven were irradiated in November, 1999 and June, 2000, respectively. A 1.5 cm-wide x 1.5 xm-high array of equally space approximately equals 20-30 micrometers wide, upright microbeams spaced at 210 micrometers intervals was propagated horizontally, left to right, through the cerebella of the prone, anesthetized piglets. Skin-entrance intra-microbeam peak adsorbed doses were uniform, either 150, 300, 425, or 600 gray (Gy). Peak and inter-microbeam (valley) absorbed doses in the cerebellum were computed with the PSI version of the Monte Carlo code GEANT and benchmarked using Gafchromic and radiochromic film microdosimetry. For approximately equals 66 weeks [first litter; until euthanasia], or approximately equals 57 weeks [second litter; until July 30, 2001] after irradiation, the littermates were developmentally, behaviorally, neurologically and radiologically normal as observed and tested by experienced farmers and veterinary scientists unaware of which piglets were irradiated or sham-irradiated. Morever, MRT implemented at the ESRF with a similar array of microbeams and a uniform skin-entrance peak dose of 625 Gy, followed by immunoprophylaxis, was shown to be palliative or curative in young adult rats bearing intracerebral gliosarcomas. These observations give further credence to MRTs potential as an adjunct therapy for brain tumors in infancy, when seamless therapeutic irradiation of the brain is hazardous.

Necrosis of Hippocampus and Piriform Lobe in 38 Domestic Cats with Seizures: A Retrospective Study on Clinical and Pathologic Findings

The clinical records of 38 cats (1985-1995) with a neuropathologically confirmed diagnosis of necrosis of the hippocampus and occasionally the lobus piriformis were evaluated retrospectively. There was no sex or breed predisposition. Most cats were between 1 and 6 years of age (mean age 35 months) and had either generalized or complex-partial seizures of acute onset and rapid progression. The seizures had a tendency to become recurrent and to present as clusters or even status epilepticus later in the course of the disease. Fourteen cats died spontaneously, and 24 were euthanized. Histopathologic examination revealed bilateral lesions restricted to the hippocampus and occasionally the lobus piriformis. The lesions seemed to reflect different stages of the disease and consisted of acute neuronal degeneration to complete malacia, affecting mainly the layer of the large pyramidal cells but sometimes also the neurons of the dentate gyrus and the piriform lobe. The clinical, neuropathologic, and epidemiologic findings suggest that the seizures in these cats were triggered by primary structural brain damage, perhaps resulting from excitotoxicity. The cause remains unknown, but epidemiologic analysis suggests an environmental factor, probably a toxin.

Intracranial neoplasia in 61 cats: localisation, tumour types and seizure patterns.

The purpose of this study was to analyse retrospectively a feline population with intracranial neoplastic diseases, to document seizure patterns in these animals and to determine whether partial seizures were more frequently associated with structural brain lesions then generalised seizures. In addition, a comparison was made within the population with intracranial neoplasia between two groups of cats: one with and one without seizures. Special emphasis was given to the evaluation of tumour type, localisation and size of the lesion and its correlation with seizure prevalence. Sixty-one cats with histopathological diagnosis of intracranial tumour were identified. Fourteen cats (23%; group A) had a history of seizure(s). Forty-seven cats (77%; group B) had no history of seizure(s). Generalised tonic-clonic seizures were seen in eight cats (57%) and were the most common seizure pattern in our cats with intracranial neoplasia. Clusters of seizures were observed in six cats. Status epilepticus was observed in one patient. The mean age of the cats was 7.9 years within group A (median 8.5) and 9.3 years (median 10) within group B. The cats with lymphoma within both groups were significantly younger than cats with meningioma. In both groups meningioma and lymphoma were confirmed to be the most frequent tumour type, followed by glial cell tumours. The prevalence of the seizures in patients with glial cell tumours was 26.7%, 26.3% in patients with lymphomas and 15% in cases with meningiomas. In 33 cases (54.1%) the tumours were localised in the forebrain, 15 tumours (24.6%) were in the brainstem, four (6.6%) in the cerebellum and nine tumours (14.7%) had multifocal localisation. Parietal lobe and basal ganglia mostly affected group A. In group B tumours were most frequently located in the parietal and frontal lobes as well as in the diencephalon. A positive association was documented between the localisation of a tumour in the forebrain and seizure occurrence.

Influence of intervertebral disc fenestration at the herniation site in association with hemilaminectomy on recurrence in chondrodystrophic dogs with thoracolumbar disc disease: a prospective MRI study.

OBJECTIVE To describe the influence of fenestration at the disc herniation site on recurrence in thoracolumbar disc disease of chondrodystrophoid dogs. STUDY DESIGN Prospective clinical study. ANIMALS Chondrodystrophic dogs (n=19). METHODS Dogs were divided into 2 groups: group 1 (9 dogs) had thoracolumbar disc extrusion (Hansen type I) treated by hemilaminectomy and concomitant fenestration of the affected intervertebral disc and group 2 (10 dogs) had hemilaminectomy without fenestration. All dogs had 3 magnetic resonance imaging (MRI) examinations: preoperatively, immediately postoperatively to assess removal of herniated disc material, and again 6 weeks after surgery. RESULTS There were 13 male and 6 female dogs; mean age, 7.1 years. Thoracolumbar disc herniation was confirmed with MRI. Immediate post surgical MRI revealed that the herniated disc removal was complete in all but 1 dog and that fenestration did not lead to complete removal of nucleus pulposus within the intervertebral disc space. On the 3rd MRI examination, none of the group 1 dogs had further disc material herniation at the fenestrated site. Six of the 10 group 2 dogs had a recurrence of herniation leading to clinical signs in 3 dogs (pain in 2 dogs, paresis in 1 dog). CONCLUSION In thoracolumbar disc herniation, fenestration of the affected intervertebral disc space prevents further extrusion of disc material. CLINICAL RELEVANCE Fenestration reduces the risk of early recurrence of disc herniation and associated postoperative complications.

Daily Controlled Physiotherapy Increases Survival Time in Dogs with Suspected Degenerative Myelopathy

The purposes of the study reported here were to evaluate the signalment and clinical presentation in 50 dogs with degenerative myelopathy, to evaluate whether mean survival time was significantly affected by various means of physiotherapy performed in 22 dogs, and to determine whether neurologic status, anatomic localization, or age at onset had an influence on survival time in dogs that received physiotherapy. We found a significant (P < .05) breed predisposition for the German Shepherd Dog, Kuvasz, Hovawart, and Bernese Mountain Dog. Mean age at diagnosis was 9.1 years, and both sexes were affected equally. The anatomic localization of the lesion was spinal cord segment T3-L3 in 56% (n = 28) and L3-S3 in 44% (n = 22) of the dogs. Animals that received intensive (n = 9) physiotherapy had longer (P < .05) survival time (mean 255 days), compared with that for animals with moderate (n = 6; mean 130 days) or no (n = 7; mean 55 days) physiotherapy. In addition, our results indicate that affected dogs which received physiotherapy remained ambulatory longer than did animals that did not receive physical treatment.

Gastric mucosal lesions in dogs with acute intervertebral disc disease: characterization and effects of omeprazole or misoprostol.

We characterized gastric mucosal lesions in dogs with acute degenerative disc disease treated by surgery and corticosteroid administration. The effect of omeprazole and misoprostol on gastric lesions in these dogs was also evaluated. Dogs were randomly assigned to 1 of 2 treatment groups or to the control group. Treatment consisted of omeprazole at 0.7 mg/kg orally once daily, or misoprostol at 2 microg/kg orally 3 times daily. All 3 groups received dexamethasone at 2 mg/kg on day 0, prednisolone at 2 mg/kg on day 1. prednisolone at 1 mg/kg on day 2, and prednisolone at 0.5 mg/kg on all further days (range, 5-6 days). Endoscopic examination was performed on day 0 and 5-6 days later. Four regions of the stomach were qualitatively scored from 1 to 12 based on the presence of submucosal hemorrhage, erosion, or ulceration, with ulceration receiving the highest numerical score. Nineteen of 25 dogs had gastric mucosal lesions at the beginning of the study. No significant difference was found in the gastric lesion score among the 3 groups at the end of the study. Gastric mucosal lesions were concluded to be common in dogs with acute degenerative disc disease treated with corticosteroids. Neither omeprazole nor misoprostol at the doses used was effective in healing or preventing the further development of gastric mucosal lesions.

Comparative study of vertebral fractures and luxations in dogs and cats

The purpose of this retrospective study was to compare patterns of vertebral fractures and luxations in 42 cats and 47 dogs, and to evaluate the impact of species-related differences on clinical outcome. Data regarding aetiology, neurological status, radiographic appearance and follow-up were compared between the groups. The thoracolumbar (Th3-L3) area was the most commonly affected location in both cats (49%) and dogs (58%). No lesions were observed in the cervical vertebral segments in cats, and none of the cats showed any signs of a Schiff-Sherrington syndrome. Vertebral luxations were significantly more frequent in dogs (20%) than in cats (6%), whereas combined fracture-luxations occurred significantly more often in cats (65%) than in dogs (37%). Caudal vertebral segment displacement was mostly dorsal in cats and ventral in dogs, with a significant difference in direction between cats and large dogs. The clinical outcome did not differ significantly between the two populations, and was poor in most cases (cats: 61%; dogs: 56%). The degree of dislocation and axis deviation were both significantly associated with a worse outcome in dogs, but not in cats. Although several differences in vertebral fractures and luxation patterns exist between cats and dogs, these generally do not seem to affect outcome.

Spontaneous lumbar intervertebral disc protrusion in cats: literature review and case presentations

Reports on intervertebral disc disease in cats are rare in the veterinary literature. It has been postulated that intervertebral disc protrusion is a frequent finding during necropsy in cats, without having any clinical relevance (King and Smith 1958, King & Smith 1960a, King & Smith 1960b). However, a total of six cases with disc protrusions and clinically significant neurological deficits have been reported over the past decade. (Heavner 1971, Seim & Nafe 1981, Gilmore 1983, Littlewood et al 1984, Sparkes & Skerry 1990, Bagley et al 1995). As in dogs, there are also two types of intervertebral disc disease in cats: Hansens type I (extrusion), and type II (herniation). Cervical spinal cord involvement was more commonly recognised in cats than the lumbar or the thoraco lumbar area. Cats over 15 years were mainly affected (King & Smith 1958, King & Smith 1960a, King & Smith 1960b). We describe two cats with lumbar intervertebral disc protrusions. Emphasis is placed on differential diagnoses, treatment and follow-up.

Quantitative electroencephalographic findings in beagles anaesthetized with propofol

The purpose of this study was to assess quantitative electroencephalography (q-EEG) in 10 healthy beagle dogs under propofol anaesthesia in order to determine objective guidelines for diagnostic electroencephalographic (EEG) recordings and interpretation. The basic pattern after preliminary visual examination of EEG recordings was characterized by spindles, k-complexes, vertex sharp transients, and positive occipital transients that were superimposed on the slow background activity. The results of the q-EEG were characterized by the prevalence of slow rhythms delta and theta, both in absolute and relative power spectrum analysis, while fast rhythms (alpha and beta) were poorly represented. The distribution of single frequency bands was widespread for delta, focal for frontal and central for theta, as well as for most alpha and beta patterns. The present study has shown that the use of quantitative EEG gives information on the frequency content of the bio-electrical activity and defines the distribution of the single frequency bands under a standardized anaesthetic protocol.

Effects of adjunct electroacupuncture on severity of postoperative pain in dogs undergoing hemilaminectomy because of acute thoracolumbar intervertebral disk disease

OBJECTIVE To compare severity of postoperative pain in dogs undergoing hemilaminectomy because of acute thoracolumbar intervertebral disk disease treated with a combination of conventional analgesics and electroacupuncture (EAP) or with conventional analgesics alone. DESIGN Controlled clinical trial. ANIMALS 15 dogs undergoing surgery because of acute thoracolumbar disk disease. PROCEDURES Dogs were alternately assigned to treatment (conventional analgesics and adjunct EAP) and control (conventional analgesics alone) groups. Analgesic treatment was adjusted as necessary by the attending clinician, who was not aware of group assignment. Pain scores were assigned 1, 3, and 12 hours after surgery and every 12 hours thereafter for 72 hours by the same individual who performed acupuncture treatments. RESULTS Total dose of fentanyl administered during the first 12 hours after surgery was significantly lower in the treatment group than in the control group, but dosages of analgesics administered from 12 through 72 hours after surgery did not differ between groups. Pain score was significantly lower in the treatment group than in the control group 36 hours after surgery, but did not differ significantly between groups at any other time. CONCLUSIONS AND CLINICAL RELEVANCE Results provided equivocal evidence that adjunct EAP might provide some mild benefit in regard to severity of postoperative pain in dogs undergoing hemilaminectomy because of acute thoracolumbar intervertebral disk disease.