Definitive-intent uniform megavoltage fractioned radiotherapy protocol for presumed canine intracranial gliomas: retrospective analysis of survival and prognostic factors in 38 cases (2013-2019).

BACKGROUND: Radiotherapy (RT) is currently considered the treatment of choice for presumed canine intracranial gliomas. However, variable therapeutic responses are described, due to heterogeneous populations and different radiation methods or protocols. Only one study dedicated to intracranial suspected glioma highlighted prognostic criteria. Determination or confirmation of specific clinical and imaging prognostic factors may guide the therapeutic management of these tumours. The objectives were to provide data on long-term clinical outcome (including quality of life, QoL) and to determine specific prognostic factors associated with survival time. We report a single-institution retrospective study, including all dogs with suspected symptomatic primary solitary intracranial glioma, treated with a complete uniform fractionated megavoltage radiation protocol of 15x3Gy over 5 weeks, between January 2013 and February 2019. Thirty-eight client-owned dogs were included. Medical records were retrospectively evaluated for median overall survival time (MST), clinical and imaging responses. Prognostic factors on survival were researched in terms of signalment, clinical presentation, tumour imaging characteristics and response following RT. Finally, the RT's impact on the dogs' clinical signs and Qol were evaluated by the owners. RESULTS: The disease-specific MST was 698 days (95% CI: 598-1135). Survival at 1 and 2 years were respectively 74.2 ± 7.4% and 49.0 ± 9.8%. Initial clinical signs were related to survival, as well as tumour characteristics such as cystic-pattern, mass effect and Tumour/Brain volume ratio. No significant adverse effect or radiotoxicity was observed. CONCLUSIONS: RT appears as a safe and effective treatment for canine intracranial gliomas, allowing long-term tumour control, improvement of life's quality and management of associated clinical signs. The initial clinical signs and MRI characteristics (Tumour/Brain volume ratio, cyst-like lesion and mass effect) may help predict the prognosis.

Anatomical and mesoscopic characterization of the dystrophic diaphragm: An in vivo nuclear magnetic resonance imaging study in the Golden retriever muscular dystrophy dog.

Because respiratory failure remains a major issue in Duchenne Muscular Dystrophy patients, respiratory muscles are a key target of systemic therapies. In the Golden Retriever Muscular Dystrophy (GRMD) dogs, the disease shows strong clinical and histological similarities with the human pathology, making it a valuable model for preclinical therapeutic trials. We report here the first nuclear magnetic resonance (NMR) imaging anatomical study of the diaphragm in GRMD dogs and healthy controls. Both T1- and T2-weighted images of the diaphragm of seven healthy and thirteen GRMD dogs, from 3 to 36 months of age, were acquired on a 3 tesla NMR scanner. Abnormalities of texture and shape were revealed and consisted of increases in signal intensity on T2-weighted images and in signal heterogeneity on both T1- and T2-weighted images of the dystrophic diaphragm. These abnormalities were associated with a significant thickening of the muscle and we identified a clear 8-mm-threshold distinguishing clinically preserved GRMD dogs from those more severely affected. In this study, we demonstrated the feasibility of NMR imaging of the diaphragm and depicted several anatomical and mesoscopic anomalies in the dystrophic diaphragm. NMR imaging of the diaphragm shows a promise as an outcome measure in preclinical trials using GRMD dogs.

Facial and vestibular neuropathy of unknown origin in 16 dogs.

OBJECTIVES: The aim of this study was to describe the signalment, clinical presentation, diagnostic findings and long-term follow-up in dogs with concomitant facial and vestibular neuropathy of unknown origin. METHODS: Appropriate cases were located through medical record searches. Inclusion criteria comprised dogs that had: clinical signs of facial paralysis with concomitant peripheral vestibular syndrome, thyroid function tests, no abnormalities on magnetic resonance imaging of the brain and tympanic bullae, and cerebrospinal fluid analysis. RESULTS: Sixteen dogs met the inclusion criteria. Facial paralysis had acute onset (<24 hours) in all dogs, thyroid function was within normal limits. There was albuminocytologic dissociation in cerebrospinal fluid of 69% of the dogs. There was complete resolution of clinical signs in 31% of the dogs but 38% showed long-term vestibular deficits, 46% developed hemifacial contracture, 15% had permanent facial paralysis and 15% relapsed. CLINICAL SIGNIFICANCE: Facial and vestibular neuropathy of unknown origin shares similarities with idiopathic facial paralysis. The prognosis for return of normal facial and vestibular function is guarded and there may be relapse after recovery.

Comprehensive longitudinal characterization of canine muscular dystrophy by serial NMR imaging of GRMD dogs.

The Golden Retriever Muscular Dystrophy (GRMD) dog is the closest animal counterpart of Duchenne muscular dystrophy in humans and has, for this reason, increasingly been used in preclinical therapeutic trials for this disease. The aim of this study was to describe the abnormalities in canine dystrophic muscle non-invasively, quantitatively, thoroughly and serially by means of NMR imaging. Thoracic and pelvic limbs of five healthy and five GRMD dogs were imaged in a 3T NMR scanner at 2, 4, 6 and 9months of age. Standard and fat-saturated T(1)-, T(2)- and proton-density-weighted images were acquired. A measurement of T(1) and a two-hour kinetic study of muscle enhancement after gadolinium-chelate injection were also performed. Ten out of the 15 indices evaluated differed between healthy and GRMD dogs. The maximal relative enhancement after gadolinium injection and the proton-density-weighted/T(2)-weighted signal ratio were the most discriminating indices. Inter-muscle heterogeneity was found to vary significantly for most of the indices. The body of data that has been acquired here will help in designing and interpreting preclinical trials using dystrophin-deficient dogs.

Minimally invasive video-assisted cervical ventral slot in dogs. A cadaveric study and report of 10 clinical cases.

OBJECTIVES: To investigate the feasibility of a minimally invasive video-assisted (MIVA) cervical ventral slot (VS) in dogs without the use of fluoroscopy, and to report our initial clinical experiences in dogs. METHODS: Two surgical approaches to an intervertebral disk space (IVDS) were performed in eight intact canine cadavers to determine the feasibility of MIVA-VS using the Destandau Endospine™ Devicea (DED) without fluoroscopic guidance. In a subsequent clinical study, 10 client-owned dogs admitted for a Hansen type 1 disk extrusion underwent a MIVA-VS. Recorded data in both studies included: incision lengths, correct targeting of the IVDS, technical problems encountered during the procedure, and potential damage to major anatomical structures. In the 10 clinical cases, duration of the procedure and clinical outcome at five and 12 days, and after a minimum of three months were also recorded. RESULTS: Correct exposure of the targeted IVDS was achieved in all cases. There was no major iatrogenic damage. Mean skin incision length was 39 mm and mean surgery time was 52 minutes. The technique provided increased illumination and magnification of the surgical field. Recovery was uneventful in all cases. CLINICAL RELEVANCE: The present study provided evidence that MIVA-VS using the DED was feasible and a relatively fast and safe procedure for the treatment of cervical disk herniation. Advantages of the technique seemed to include shorter incisions, less dissection and improved visibility.

Chronic traumatic brain injury in a dog.

Chronic traumatic brain injury is rare in man and has not been previously documented in dogs. This report describes a 2-year-old female American Staffordshire bull terrier that was referred with forelimb and hindlimb ataxia, decreased vigilance and disorientation following repeated aggression and physical abuse by its owner. A diffuse cortical lesion was suspected. Cerebrospinal fluid analysis revealed neutrophilic pleocytosis and computed tomography showed marked widening of the cerebral sulci with mild bilateral ventriculomegaly. The dog was humanely destroyed in view of the poor prognosis. Necropsy examination revealed narrowing of the cerebral cortical gyri and consequent widening of the sulci without distortion or displacement of the neural parenchyma. These features were consistent with bilateral diffuse cortical atrophy. Microscopically, there were chronic subarachnoid haemorrhages and the cortical subpial layer displayed spongiosis, capillary hyperplasia, astrocytosis, microgliosis and frequent neuronal necrosis occurring in a characteristic laminar pattern. This histopathological pattern of damage was significantly different from that previously described in people suffering from repeated traumatic brain injuries over a long period of time.

Spinal cryptococcoma in an immunocompetent cat.

This report describes an unusual case of primary cryptococcoma in the proximal thoracic spinal cord of an 11-year-old immunocompetent cat from a farm on which there were large numbers of pigeons. This animal was referred for examination with progressive paralysis and shown to be free from feline immunodeficiency virus, feline leukaemia virus, feline coronavirus and Toxoplasma gondii. It died 2 months later. At necropsy, the only lesion detected was a malacic area, 4cm in length, in the spinal cord. Histopathological examination of the spinal cord revealed severe granulomatous inflammation associated with large numbers of encapsulated yeast cells. In addition to the granulomatous host response, necrosis, digestion chambers, Gitter cells, spheroids and lymphocytic perivascular cuffs were features of the malacic areas. Immunohistochemistry confirmed the presence of Cryptococcus neoformans var. grubii yeast cells.

Characterization of dystrophic muscle in golden retriever muscular dystrophy dogs by nuclear magnetic resonance imaging.

The Golden Retriever Muscular Dystrophy dog lacks dystrophin. Disease progression in this model shares many similarities with the Duchenne muscular dystrophy, both from anatomico pathological and clinical standpoints. The model is increasingly used in pre-clinical trials but needs to be further investigated, particularly with reference to the evaluation of therapies. The aim of this study was to identify quantitative indices that would help characterize the dystrophic dog non-invasively using NMR imaging. Two-month-old dystrophic dogs and healthy control animals were scanned at 4T. Standard T2- and T1-weighted images, fat-saturated T1-weighted images pre- and post-gadolinium chelate injection were acquired and kinetics of muscle enhancement were studied over a 2-h period. Several indices were found to be abnormally high in dystrophic dogs: the T2-weighted/T1-weighted signal ratio, T2-weighted image heterogeneity and maximal signal enhancement post-gadolinium. These may be proposed to evaluate muscle structural alterations non-invasively in this disease.

First isolation of Mycobacterium microti (Llama-type) from a dog.

We report the first isolation of Mycobacterium microti from a dog with lesions of acute peritonitis. The isolate was demonstrated to be M. microti of Llama-Type by spoligotyping. Epidemiological implications of the isolation of this possibly zoonotic agent from a dog are discussed.

Theileria annulata in CD5(+) macrophages and B1 B cells.

Theileria parasites infect and transform bovine leukocytes. We have analyzed laboratory-established Theileria sp.-infected leukocyte lines and observed that transformed macrophages express CD5. Low-level expression of CD5 by macrophages was further confirmed on three independent Theileria annulata clinical isolates from Tunisia. Interestingly, the fourth CD5(+) clinical isolate (MB2) was morphologically different, expressed surface immunoglobulin M (IgM) and BoLA class II, and had rearranged Ig light-chain genes. To demonstrate that MB2 did indeed contain CD5(+) B cells, individual clonal lines were obtained by limiting dilution, and CD5 expression and Ig gene rearrangement were confirmed. This suggests that in natural infections T. annulata can invade and transform CD5(+) B cells.