Supratentorial arachnoid cyst management by cystoperitoneal shunt in a 1-year-old European cat.

Arachnoid cysts are defined as an accumulation of fluid within the arachnoid membrane. Feline intracranial arachnoid cysts are seldom reported, with only three cases in the veterinary literature. A 1-year-old male neutered European cat with a 24 h history of seizures was presented to the small animal neurology department at Vetagro Sup, Lyon. Magnetic resonance imaging (MRI) revealed a large intracranial arachnoid cyst ventral to the brain in the left temporal area. Cystoperitoneal shunt placement resulted in complete resolution of the cyst without recurrence (follow-up MRIs 3 weeks and 21 months after surgery). Anticonvulsant treatment (phenobarbital 2.5 mg/kg q12h) was initiated at presentation and gradually stopped after 17 months. Seizures recurred 4 months after ending treatment, and seizure therapy was therefore restarted at the initial dose. We report a case of an intracranial arachnoid cyst in an unusual location not previously described. A cystoperitoneal shunt resolved the cyst without complications. Maintenance anticonvulsant treatment was required to control symptomatic epilepsy.

Spinal neurenteric cyst in a dog.

A 2-year-old female crossbreed dog was presented with progressive ataxia and paraparesis. A T3-L3 spinal lesion was determined by neurological examination. Magnetic resonance imaging (MRI) revealed an ovoid-shaped, well-circumscribed mass affecting the spinal cord at the level of the T9 vertebra. A left hemilaminectomy and a durotomy at the level of T9 allowed discovery of an ovoid deformation of the meninges with a cystic appearance. En bloc removal was performed and appeared to be complete. Pathological analysis showed a voluminous cystic lesion lined by a heterogeneous epithelium. Three types of epithelium were present: a pseudostratified columnar epithelium, a stratified squamous epithelium and a transitional epithelium. Mucus production, the morphology of some cells with microvilli at the apical pole and immunohistochemical assays were highly in favor of an endodermal origin of the cyst. The age of the dog, anamnesis, MRI study and histological findings were consistent with an intradural neurenteric cyst as described in humans. Total surgical removal led to a progressive clinical improvement with no recurrence at 18 months. We report an unusual intradural extramedullary cyst, called a neurenteric cyst, in a 2-year-old female crossbreed dog. This type of cyst is well-known in humans but has never been described in dogs. We propose that neurenteric cysts should be included in the differential diagnoses for tumor-like or cystic intradural lesions in the young dog. Prognosis for this type of cyst seems to be good, as total surgical removal led to a progressive clinical improvement with no recurrence at 18 months.

Imaging and histological characterization of a human brain xenograft in pig: the first induced glioma model in a large animal.

The prognosis of glioblastoma remains poor despite significant improvement in cytoreductive surgery, external irradiation and new approach of systemic treatment as antiangiogenic therapy. One of the issues is the low concentration in the infiltrated parenchyma of therapeutic agent administered intravenously mainly due to the blood-brain barrier. An intracerebral injection is advocated to overpass this barrier, this kind of administration need a low flow and continuous injection. The development of sophisticated implanted devices for convection-enhanced delivery is a mandatory step to have a controlled released of a therapeutic agent in glioblastoma treatment. Before testing such a device in a clinical trial a serious preclinical studies are required, in order to test it in realistic conditions we have develop the first induced high grade glioma model in a non-rodent animal: the pig. 21 pigs have been implanted in the parietal lobe with human glioblastoma cell lineage under a chemical immunosuppression by ciclosporine. A MRI follow up was then realized. 15 pigs have been implanted with U87MG, 14 have presented a macroscopic significant tumor, with radiological and anatomapathological characteristics of high grade glioma. 6 pigs were implanted with G6, stem-like cells tumors of glioblastoma, 1 pig develops a macroscopic tumor. This is the first reproducible glioma model in a large animal described, it open the way to preclinical studies to test implanted devices in anatomic realistic conditions, without the ethical issues of a primate use.

Sucrose solution freezing studied by magnetic resonance imaging.

Ice formation of a 20% w/v sucrose solution was monitored during the freezing process by magnetic resonance imaging (MRI). An original experimental setup was designed with oil as a cooling fluid that allows accurate control of the temperature. The NMR signal intensity of particular sampled volumes was observed during the entire cooling period, from 0 to -50 degrees C, showing a peak characteristic to a transition before the loss of the signal. Moreover, spatial ice distribution of the frozen matrix was observed by high resolution MRI with an isotropic resolution of 78x78x78microm(3). MRI has proved to be a novel technique for determining the glass transition temperature of frozen sucrose solutions, in the concentration range where calorimetric measurements are not feasible.

Kinetics of anaerobic metabolism in human skeletal muscle: influence of repetitive high-intensity exercise on sedentary dominant and non-dominant forearm. A 31P NMR study.

Potential differences were assessed between the dominant (D) and non-dominant (ND) forearms of sedentary subjects during anaerobic exercise. Subjects performed voluntary concentric contractions of D and ND forearm muscle during a series of three high-intensity (60% of the maximal voluntary contraction force (MVC)) exercise bouts. The time-dependent changes in intracellular pH (pH(i)), Pi, and PCr concentrations, and their relation to muscular work were examined using 31P magnetic resonance spectroscopy (MRS) techniques, and revealed that D forearm metabolic kinetics in sedentary individuals are improved during repetitive high-intensity exercise compared to their respective ND forearm muscle. We postulate that the more regular and preferential utilization of the D limb leads to a "trained-like" condition.