Morphometric analysis of sciatic nerve and its main branches in the rabbit.

In the rabbit the myelinated fibres with the largest diameter originating from the sciatic nerve distribute mainly into the peroneal nerve, even though there is no difference in the density of myelinated fibres of the representative unit between the sciatic nerve and its branches. The distribution of the myelinated fibre diameters is unimodal in the sciatic nerve, but bimodal both in the peroneal and tibial nerves. The quotient axon diameter/fiber diameter (g ratio) shows a different trend between the sciatic nerve and the branches originating from it. Except for the peroneal nerve, the increase of the axon calibre corresponds to the reduction of the relative myelin sheath thickness and therefore to the reduction of internodal distance. The results show that the sciatic nerve and its terminal branches in the rabbit have morphometrical characteristics that are peculiar and differ from those of the other rodents.

[Morphometric analysis of the sciatic nerve and its principal branches in the pigeon (Columba livia)]. / Analisi morfometrica del nervo ischiatico e dei suoi rami principali nel colombo (Columba livia).

The methodological approach used in this study is to characterize the number, the density and the diameter distribution of myelinated fibers (MFs) and unmyelinated fibers (UMFs) in sciatic nerve and its main branches of pigeon. The results have shown that the fiber composition is quite variable because in pigeon there are relatively MF with thin myelin sheaths and MF with thicker sheaths. Our data suggest that morphometric analysis could represent a helpful methodological approach to better characterize these systems.

Vascular compression from goiter as an unusual cause of cerebrovascular accident.

The unusual case of a patient with goiter and left faciobrachiocrural paresis due to right temporoparietal infarction is reported. Cerebral angioscintigram and arteriography showed a brachiocephalic and right subclavian stenosis secondary to compression by an extended thyroid nodule.

Spontaneous bilateral anterior cerebral artery occlusion resulting in akinetic mutism. A case report.

An unusual case concerning a patient with akinetic mutism (AM) due to spontaneous bilateral anterior cerebral artery occlusion is reported. Brain CT scan revealed the presence of mild low density foci presenting an irregular enhancement, which followed the distribution of mesial frontal gyri and paracentral lobulus, bilaterally. Right and left carotid angiographies showed bilateral occlusion of the anterior cerebral artery. Our case is characterized by an exclusive localization of the infarction in the frontal cortex. This finding suggests that a limited damage involving the anterior cerebral arteries territory could be, on its own, responsible for the AM syndrome.

[Juvenile spongiform encephalopathy with unusual pathomorphologic findings]. / Encefalopatia spongiforme giovanile con insoliti reperti patomorfologici.

A 27-year-old man presented disturbances of gait and language, quickly followed by intellectual deterioration, tetraplegia, anarthria and myoclonus. Histological examination of a cerebral biopsy showed not only cortical changes consistent with the diagnosis of Creutzfeldt-Jakob disease, but also many amyloid-plaques with variable morphology. The diagnostic interpretation of the case particularly as to concern his relationship to s.c. Gerstmann-Strüssler syndrome is discussed.