Fluorescence labeling methods influence the aggregation process of α-syn in vitro differently.

In a previous study, the coexistence of different aggregation pathways of insulin and ß-amyloid (Aß) peptides was demonstrated by correlative stimulated emission depletion (STED) microscopy and atomic force microscopy (AFM). This had been explained by suboptimal proteins labeling strategies that generate heterogeneous populations of aggregating species. However, because of the limited number of proteins considered, the failure of the fluorescent labeling that occurs in a large portion of the aggregating fibrils observed for insulin and Aß peptides, could not be considered a general phenomenon valid for all molecular systems. Here, we investigated the aggregation process of α-synuclein (α-syn), an amyloidogenic peptide involved in Parkinson's disease, which is significantly larger (MW ∼14 kDa) than insulin and Aß, previously investigated. The results showed that an unspecific labeling procedure, such as that previously adopted for shorter proteins, reproduced the coexistence of labeled/unlabeled fibers. Therefore, a site-specific labeling method was developed to target a domain of the peptide scarcely involved in the aggregation process. Correlative STED-AFM illustrated that all fibrillar aggregates derived from the aggregation of α-syn at the dye-to-protein ratio of 1 : 22 were fluorescent. These results, demonstrated here for the specific case of α-syn, highlight that the labeling artifacts can be avoided by careful designing the labeling strategy for the molecular system under investigation. The use of a label-free correlative microscopy technique would play a crucial role in the control of the setting of these conditions.

Vermian subtentorial arteriovenous malformation supplied by the artery of Wollschlaeger and Wollschlaeger.

BACKGROUND: The artery of Wollschlaeger and Wollschlaeger is a tentorial branch of the superior cerebellar artery: due to its small diameter, it is not usually seen in normal angiograms except when enlarged in the setting of a dural AVF or tentorial meningioma. Its presence has been rarely described in the Literature. CASE REPORT: herein we describe the first ever reported case of a vermian subtentorial arteriovenous malformation supplied by the artery of Wollschlaeger and Wollschlaeger in 70 year old female patient. CONCLUSION: vermian subtentorial AVMs supplied by the artery of Wollschlaeger and Wollschlaeger are extremely rare vascular malformations. The presence of the artery of Wollschlaeger and Wollschlaeger must be carefully evaluated during preoperative surgical planning due to its key role in the supply of vascular malformation and to decrease the risk of intra operative bleeding during surgery.

Transverse sinus thrombosis after posterior fossa surgery for cerebellar tumor treated by endovascular thrombectomy. A case report.

Dural sinus thrombosis is a rare complication after posterior fossa surgery, particularly in cerebellar tumour surgery. The authors describe the case of a young male patient who presented a postoperative neurological deterioration due to transverse sinus thrombosis after surgery for cerebellar medulloblastoma. He was treated by mechanical clot thrombectomy using an endovascular catch system technique without anticoagulation therapy. Final angiographic recanalization was obtained. This kind of endoluminal mechanical revascularization is an efficacious method to treat dural sinus thrombosis during perioperative time but speed in diagnosis is crucial for clinical outcome.