Otopathy secondary to trigeminal schwannoma in a Quarter Horse

Otitis media secondary to trigeminal nerve (CN-V) paralysis is described in dogs and humans but not in horses. An 18-month-old Quarter Horse colt was presented with history of mastication difficulties and a nonhealing corneal ulcer. Clinical findings were consistent with paralysis of the right CN-V. Computed tomography imaging showed otopathy media and a mass at the root of the CN-V. The colt was euthanised due to poor prognosis. Post-mortem magnetic resonance imaging showed enlargement of the right CN-V which was slightly hyperintense on T2W. Histopathology of the mass revealed fusiform tumoural cells, positive on vimentin- and S100 immunohistochemistry, consistent with a schwannoma. Otitis media was presumed secondary to CN-V paralysis and denervation of the right tensor veli palatini muscle involved in opening of the Eustachian tube. This is the first case of trigeminal schwannoma and secondary otopathy media described in a horse, which highlights the importance of imaging in investigating trigeminal nerve paralysis.     

Spatial distribution of lineages of oak powdery mildew fungi in France, using quick molecular detection methods

? Powdery mildew is a major fungal disease of oaks in Europe. Recent studies using internal transcribed spacer (ITS) sequences suggested the presence of four different lineages (putative species). The objective of the study was to investigate the spatial distribution of these lineages/species and, in particular, to test the hypothesis of a spatial differentiation, at various scales: regional (France), altitudinal (a Pyrenean transect) and local (within a forest plot).

? Detection methods for the four ITS types were developed: (1) single strand conformation polymorphism analysis (SSCP); (2) PCR amplifications, for which specific primers were designed. SSCP proved to be efficient for the detection of Erysiphe alphitoides and E. quercicola types. In contrast, the rarer ITS types corresponding to E. hypophylla and Phyllactinia guttata (sensu lato) were only detected by specific amplification.

? The study confirmed the strong predominance of the ITS sequence associated with E. alphitoides at all spatial scales (with a frequency higher than 80%). Isolates presumably belonging to E. quercicola (i.e. with same ITS type), a recently described species not yet recorded in Europe, were also found in all French regions at a significant frequency (15% at national level).

? No pattern of spatial differentiation between the putative species could be demonstrated: E. alphitoides was often found in association with different ITS types in the same region, the same tree, and even in the same lesion.

     

Dynamic MRI and thermal simulation to interpret deformation and water transfer in meat during heating

Understanding and controlling structural and physical changes in meat during cooking is of prime importance. Nuclear magnetic resonance imaging (MRI) is a noninvasive, nondestructive tool that can be used to characterize certain properties and structures both locally and dynamically. Here we show the possibilities offered by MRI for the in situ dynamic imaging of the connective network during the cooking of meat to monitor deformations between 20 and 75 °C. A novel device was used to heat the sample in an MR imager. An MRI sequence was developed to contrast the connective tissue and the muscle fibers during heating. The temperature distribution in the sample was numerically simulated to link structural modifications and water transfer to temperature values. The contraction of myofibrillar and collagen networks was observed at 42 °C, and water began to migrate toward the interfascicular space at 40 °C. These observations are consistent with literature results obtained using destructive and/or nonlocalized methods. This new approach allows the simultaneous monitoring of local deformation and water transfer, changes in muscle structure and thermal history.     

Influence of culture medium pH on internalization, growth and phenotypic plasticity of Neospora caninum

Neospora caninum, a strictly intracellular protozoan, is a major leading cause of parasite-induced abortion in cattle. A widely held view of N. caninum infection is that both cellular proliferation and stage interconversion (tachyzoite-bradyzoite transformation) are triggered, perhaps even modulated by, changes in cultural conditions. This study tested the hypothesis that exposure of N. caninum tachyzoites to different pH culture media affects the parasite's entry, proliferation and cyst formation in cultured cells. The endocytic pathway for N. caninum entry into the K562 cell line was found to be mediated by low pH of culture medium. Internalization of N. caninum by host cells was significantly increased in acidic and alkaline culture medium compared to cells maintained in neutral medium as revealed by transmission electron microscopy. Parasite proliferation within Vero cells was assessed by plaque formation assay and was found to be highest when pH level was optimum, paralleled by a decrease in the number of cysts. In contrast, parasite encystation increased when the pH level was alkaline or acidic, as evaluated by indirect immunofluorescence and immunocytochemical analyses. Acidic pH regardless of state of host cell infection suppressed the rate of host cell division. These findings suggest that culture medium pH has a determinable effect on the host cell-N. caninum interaction and support the hypothesis that pH of culture medium influence the entry, growth, and phenotypic plasticity of N. caninum in mammalian cells.