Hippocampal subfields revealed through unfolding and unsupervised clustering of laminar and morphological features in 3D BigBrain.

The internal structure of the human hippocampus is challenging to map using histology or neuroimaging due to its complex archicortical folding. Here, we aimed to overcome this challenge using a unique combination of three methods. First, we leveraged a histological dataset with unprecedented 3D coverage, BigBrain. Second, we imposed a computational unfolding framework that respects the topological continuity of hippocampal subfields, which are traditionally defined by laminar composition. Third, we adapted neocortical parcellation techniques to map the hippocampus with respect to not only laminar but also morphological features. Unsupervised clustering of these features revealed subdivisions that closely resemble gold standard manual subfield segmentations. Critically, we also show that morphological features alone are sufficient to derive most hippocampal subfield boundaries. Moreover, some features showed differences within subfields along the hippocampal longitudinal axis. Our findings highlight new characteristics of internal hippocampal structure, and offer new avenues for its characterization with in-vivo neuroimaging.

Rarity of surgical complications after postchemotherapy nephrectomy for nephroblastoma. Experience of the International Society of Paediatric Oncology-Trial and Study "SIOP-9". International Society of Paediatric Oncology Nephroblastoma Trial and Study Committee.

The aim of the study was to assess rates and types of nephrectomy-related complications in children nephrectomized for nephroblastoma after preoperative chemotherapy. Records of 598 Wilms' tumour patients registered in the International Society of Paediatric Oncology Trial & Study No. 9 (SIOP-9), and pretreated correctly according to the protocol with vincristine + actinomycin D +/- epirubicine or adriamycin prior to nephrectomy, were retrospectively reviewed. Forty-nine patients (8%), who suffered from 54 complications, were identified. Most frequent events were small-bowel occlusions (3.7%) and tumour ruptures (2.8%). Other complications were registered in 2.0% of cases. The low rate of nephrectomy complications and no deaths related to registered ones, are another argument for preoperative chemotherapy in Wilms' tumour patients.