Computed tomography of primitive neuroectodermal tumors

The primitive neuroectodermal tumor is a neoplasm of young individuals that occurs predominantly in the supratentorial compartment. It appears on computed tomography as a bulky mass, often with calcification with predominantly homogeneous enhancement but on occasion with cystic or necrotic areas. Cerebrospinal fluid seeding was observed in more than half the cases in our series. The patients had a short survival period (7-24 months). Despite surgery, radiation, and chemotherapy, further growth of this tumor has not been prevented.     

Phosphorylation of α-Synuclein at Y125 and S129 Alters Its Metal Binding Properties: Implications for Understanding the Role of α-Synuclein in the Pathogenesis of Parkinson's Disease and Related Disorders

α-Synuclein (α-syn) is a 140-amino acid protein that plays a central role in the pathogenesis of Parkinson's disease (PD) and other synucleinopathies. However, the molecular determinants that are responsible for triggering and/or propagating α-syn aggregation and toxicity remain poorly understood. Several studies have suggested that there are direct interactions between different metals and α-syn, but the role of metal ions and α-syn in the pathogenesis of PD is not firmly established. Interestingly, the majority of disease-associated post-translational modifications (PTMs) (e.g., truncation, phosphorylation, and nitration) of α-syn occur at residues within the C-terminal region (Y125, S129, Y133, and Y136) and in very close proximity to the putative metal binding sites. Therefore, we hypothesized that phosphorylation within this domain could influence the α-syn-metal interactions. In this paper, we sought to map the interactions between the di- and trivalent cations, Cu(II), Pb(II), Fe(II), and Fe(III), and the C-terminal region of α-syn encompassing residues 107-140 and to determine how phosphorylation at S129 or Y125 alters the specificity and binding affinity of metals using electrospray ionization-mass spectrometry (ESI-MS) and fluorescence spectroscopy. We demonstrate that D115-M116 and P128-S129 act as additional Cu(II) binding sites and show for the first time that the residues P128-S129 and D119 are also involved in Pb(II) and Fe(II) coordination, although D119 is not essential for binding to Fe(II) and Pb(II). Furthermore, we demonstrate that phosphorylation at either Y125 or S129 increases the binding affinity of Cu(II), Pb(II), and Fe(II), but not Fe(III). Additionally, we also show that phosphorylations at these residues lead to a shift in the binding sites of metal ions from the N-terminus to the C-teminus. Together, our findings provide critical insight into and expand our understanding of the molecular and structural bases underlying the interactions between α-syn and metal ions, including the identification of novel metal binding sites, and highlight the potential importance of cross-talk between post-translational modifications and metal ion binding in modulating α-syn functional and aggregation properties that are regulated by its C-terminal domain.     

Iatrogenic aspiration of a large piece of a wooden spoon in a 14-year-old epilepsy patient

Foreign body aspiration in childhood is a common and life-threatening emergency. A 14-year-old male with history of mental retardation was transferred from another center to our hospital with diagnosis of foreign body aspiration. According to the anamnesis, he had been diagnosed with epilepsy a few years ago. Approximately 10 hours before admission, while at home, his parents had urgently placed a wooden spoon in the boy's mouth during a generalized tonic-clonic seizure to avoid possible airway injury. Nevertheless, he had inhaled a large piece of the wood after breaking the handle of the spoon with his teeth. Rigid bronchoscopic evaluation revealed the presence of a large piece of wood sitting vertically 2 cm beyond the glottis. Although bronchoscopic removal of the wooden piece from the trachea was difficult and prolonged, it was successful. Following this process, he presented with subcutaneous emphysema and pneumothorax in the intensive care unit (ICU). After improvement with the aid of chest tube drainage in the ICU, he was discharged from the hospital on the 3rd day of rigid bronchoscopy. Early diagnosis and urgent removal of a foreign body are very important for reducing mortality. However, complications related to the foreign body itself or the bronchoscopy may occur. In conclusion, the physical characteristics, position and location of the foreign body can influence the outcome, even in skilled hands.     

Evidence of clinical and genetic heterogeneity in autosomal dominant congenital cerulean cataracts

Autosomal dominant cerulean cataracts (ADCC) have previously been mapped to two loci: one on chromosome 17q24 and the other on chromosome 22q11.2–q12.2, which includes the ß-B2 crystallin (CRYBB2) candidate gene. Using polymorphic markers in these regions (D17S802, D17S836, D17S1806 and CRYBB2, D22S258) for linkage analysis, we excluded these loci in a large Moroccan family presenting with an unusual form of ADCC with early onset of lens opacities and rapid evolution. This finding confirms the clinical and genetic heterogeneity of autosomal dominant congenital cerulean cataracts.