Congenital hydrocephalus in three sheep: Clinical, electroencephalographic and pathological features

The clinical, electroencephalographic and neuro-pathological features of three cases (cases 1, 2 and 3) of congenital hydrocephalus in sheep were described. The observed neurological signs reflected damage in the telencephalon and brain stem. The electroencephalogram performed in case 1 and case 2 showed different patterns: symmetric and synchronous high-voltage slow-activity in case 1, and low-voltage slow-activity in case 2. By the post-mortem examination, in all the animals, dilatation of the ventricular system, especially of the lateral ventricles, associated with a glial reaction surrounding the dilated ventricles was observed. Only in case 3, a monolateral meningeal thickening at the left cerebellopontine angle seemed to be responsible for the obstructive hydrocephalus. In the other two brains (case 1 and 2), no potential anatomical cause for the hydrocephalus were detected, even if, in case 2, a compensatory form was not excluded due to the moderate hypoplasia of the cerebrum and the presence of the non-suppurative inflammation. The results of this work provide a contribution to the EEG characterisation in ovine hydrocephalus cases; nevertheless further multidisciplinary studies of a larger number of sheep could permit to better characterise the EEG pattern in ovine hydrocephalus cases.

Chronic exposure to ketamine induces neuronal lose and glial reaction in CA4 region of hippocampus

Introduction: Studies have shown that even acute single dose of ketamine is associated with neurodegeneration in hippocampus. The aim of this study was to examine the effects of chronic exposure to ketamine on hippocampus proper in young adult male rats. Materials and Method: Twenty young adult male wistar rats weighing 120-150 g were randomly divided into two groups. Experimental group received ketamine intraperitoneally at the dose of 10mg/kg for one week. The control animals only received saline. At the end ofweek animals were anesthetized and the hippocampus and adrenal were harvested for further study. Results: Cytological examination of cresyl violet stained sections of ketamine group showed dark neurons in CA4 region. The number of dark neurons in CA4 (15±3) showed meaningful difference with control (P<0.001). The weight ofwet brain in ketamine group (1.34±0.04 gr) showed significant level of difference in comparison with those of control (1.6±.2gr) (P<0.05). The presence of oligodendrocytes aggregation around degenerating and healthy looking neurons was only recognized in ketamine group. Also in ketamine exposed animals, hypertrophic astrocytes especially in white matter hilar region, were observed. Conclusion: According to our findings it could be concluded repeated or chronic ketamine use is associated neurodegeneration in CA4region of hippocampus and sever glial reaction.

The Effects of Ozurdex® (Dexamethasone Intravitreal Implant) on Experimental Proliferative Vitreoretinopathy

Purpose: To investigate a new sustained-release formulation of dexamethasone (Ozurdex®) for inhibiting proliferative vitreoretinopathy (PVR) and its effect on the expression of retinal glial reaction and inflammation in experimental PVR eyes. Methods: We used 30 pigmented rabbits for this study. One week after gas compression, the eyes were injected with 5 × 104 retinal pigment epithelial cells into the vitreous cavity to induce PVR. Concurrently, one eye also received an intravitreal injection of Ozurdex; the other eye was used as a control. PVR was graded by indirect ophthalmoscopy on days 1, 3, 7, 14, 21, and 28. The expression of the retinal glial reaction and inflammation in experimental PVR eyes were evaluated by Western blot analysis. Results: PVR severity increased gradually and peaked after 14 days, and no differences in PVR severity between the study and control groups were observed at any time point. The expression of glial fibrillary acid protein (GFAP) increased on days 7 and 14 in both the PVR control and study groups. While the use of Ozurdex in the study group showed less GFAP expression, this difference was not significant. The expression of tumor necrosis factor (TNF)-α and interleukin (IL)-6 significantly increased on days 7 and 14 in PVR control eyes. There was a significant difference in TNF-α between PVR control eyes and Ozurdex-treated eyes on days 7 (p < 0.001) and 14 (p = 0.019). Ozurdex in the study group showed lower IL-6 expression; however, this difference was not significant on days 7 (p = 0.063) and 14 (p = 0.052). Conclusions: The intravitreal injection of Ozurdex suppressed the expression of inflammatory markers; however, it did not mitigate the severity of experimental PVR in this animal model.