Endoscopic transsphenoidal approach as a promising surgical option in the treatment of craniopharyngioma

10.1530/endoabs.32.P85

Replacing Metals with Oxides in Metal-Assisted Chemical Etching Enables Direct Fabrication of Silicon Nanowires by Solution Processing

Metal-assisted chemical etching (MACE) has emerged as an effective method to fabricate high aspect ratio nanostructures. This method requires a catalytic mask that is generally composed of a metal. Here, we challenge the general view that the catalyst needs to be a metal by introducing oxide-assisted chemical etching (OACE). We perform etching with metal oxides such as RuO2 and IrO2 by transposing materials used in electrocatalysis to nanofabrication. These oxides can be solution-processed as polymers exhibiting similar capabilities of metals for MACE. Nanopatterned oxides can be obtained by direct nanoimprint lithography or block-copolymer lithography from chemical solution on a large scale. High aspect ratio silicon nanostructures were obtained at the sub-20 nm scale exclusively by cost-effective solution processing by halving the number of fabrication steps compared to MACE. In general, OACE is expected to stimulate new fundamental research on chemical etching assisted by other materials, providing new possibilities for device fabrication

Block-Copolymers Enable Direct Reduction and Structuration of Noble Metal-Based Films

Noble metal nanostructured films are of great interest for various applications including electronics, photonics, catalysis, and photocatalysis. Yet, structuring and patterning noble metals, especially those of the platinum group, is challenging by conventional nanofabrication. Herein, an approach based on solution processing to obtain metal-based films (rhodium, ruthenium (Ru) or iridium in the presence of residual organic species) with nanostructuration at the 20 nm-scale is introduced. Compared to existing approaches, the dual functionality of block-copolymers acting both as structuring and as reducing agent under inert atmosphere is exploited. A set of in situ techniques has allowed for the capturing of the carbothermal reduction mechanism occurring at the hybrid organic/inorganic interface. Differently from previous literature, a two-step reduction mechanism is unveiled with the formation of a carbonyl intermediate. From a technological point of view, the materials can be solution-processed on a large scale by dip-coating as polymers and simultaneously structured and reduced into metals without requiring expensive equipment or treatments in reducing atmosphere. Importantly, the metal-based films can be patterned directly by block-copolymer lithography or by soft-nanoimprint lithography on various substrates. As proof-of-concept of application, the authors demonstrate that nanostructured Ru films can be used as efficient catalysts for H-2 generation into microfluidic reactors

Le iponatremie

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Endoscopic endonasal approach for loco-regional recurrent clivus chordomas

Introduction. Role of surgery for loco-regional recurrences of clivus chordomas (CCs) is still debated. It has been proposed in selected cases with a curative or with palliative intent, eventually followed by radiation or chemo/radiation treatments. Only limited data on the endoscopic endonasal approach (EEA) are available. Research question. To assess the role of EEA for loco-regional recurrent CCs. Materials and Methods. All consecutive loco-regional recurrent CCs operated by EEA at our Institution from 1998 to 2021 were identified. The extension of tumor resection, symptoms control, overall survival (OS), and progression free survival (PFS) were assessed. Results. Series includes 54 patients (53.7% females, mean age 55± 14 years). Surgery was planned with a resective aim in 35 (64.8%) patients, while it was palliative in 19 (35.2%). Gross tumor removal was achieved in 24 cases (44.4%). Main complications consisted of 2 (3.7%) CSF leaks. Further local relapses were observed in 30 (55.5%) patients after 25± 24 months; 29 (53.7%) patients deceased after 34 ± 31 months. OS and PFS were lower in these cases than primary surgeries (p<0.001 and p<0.001), but cases undergone surgery with a resective aim had a significant better OS and PFS than for those treated for palliation (p<0.001). Determinants of recurrences were tumoral size (p=0.48) and previous radiotherapy (p=009). Discussion and Conclusions. EEA has proven to be effective for loco-regional recurrent CCs alleviating patients symptoms and preserving their quality of life with limited morbidities. However, because overall prognosis is poor, EEA should be reserved to selected recurrent cases

Role of endoscopic endonasal approach for craniopharyngiomas extending into the third ventricle in adults

Introduction. Recent advancements in endoscopic endonasal approach (EEA) have favored its adoption for craniopharyngiomas extended to 3rd ventricle (3VCPs). However, for lack of extensive series, its outcome, limits, and indications remain debated. Research question. To assess the EEA results of for 3VCPs and identify those factors determining the choice of this approach. Material and Methods. Records of patients with 3VCPs, consecutively operated through an EEA at our Institution were retrospectively analyzed. Demographic and clinico-radiological data, rate of tumor resection, complications and outcome at follow-up were collected. Results. Thirty-six patients (19 females, mean age: 51.1 ± 15.9 yrs) were included. Extended transplanum-transtuberculum approach was performed in all cases Radical resection was achieved in 33 patients (91.7%). At follow-up, visual deficits improved/normalized in 21 cases (58.3%), and 35 (97.2%) presented with panhypopituitarism and DI. Anatomical (displacement of the chiasm and hypothalamus), clinical (age and pre-operative visual and endocrinological function) and tumoral (consistency, presence of hydrocephalus) parameters resulted relevant in determining the choice of this approach. Discussion and Conclusion. EEA offers a valid and direct route for 3VCPs, which permits to safely manage these tumors. In our series, EEA was chosen for tubero-infundibular forms with chiasm displaces antero-superiorly, and preferred in younger patients, with visual disturbances, comprimesed endocrinological function and no hydrocephalus. It requires a specific training and should be reserved in dedicated centers. Because no single approach is ideal for every 3VCP, all surgical options should be considered as complementary and selected basing on clinical, anatomical and tumoral features of each case

Machine learning-based clinical outcome prediction in surgery for acromegaly

Purpose Biochemical remission (BR), gross total resection (GTR), and intraoperative cerebrospinal fluid (CSF) leaks are important metrics in transsphenoidal surgery for acromegaly, and prediction of their likelihood using machine learning would be clinically advantageous. We aim to develop and externally validate clinical prediction models for outcomes after transsphenoidal surgery for acromegaly. Methods Using data from two registries, we develop and externally validate machine learning models for GTR, BR, and CSF leaks after endoscopic transsphenoidal surgery in acromegalic patients. For the model development a registry from Bologna, Italy was used. External validation was then performed using data from Zurich, Switzerland. Gender, age, prior surgery, as well as Hardy and Knosp classification were used as input features. Discrimination and calibration metrics were assessed. Results The derivation cohort consisted of 307 patients (43.3% male; mean [SD] age, 47.2 [12.7] years). GTR was achieved in 226 (73.6%) and BR in 245 (79.8%) patients. In the external validation cohort with 46 patients, 31 (75.6%) achieved GTR and 31 (77.5%) achieved BR. Area under the curve (AUC) at external validation was 0.75 (95% confidence interval: 0.59–0.88) for GTR, 0.63 (0.40–0.82) for BR, as well as 0.77 (0.62–0.91) for intraoperative CSF leaks. While prior surgery was the most important variable for prediction of GTR, age, and Hardy grading contributed most to the predictions of BR and CSF leaks, respectively. Conclusions Gross total resection, biochemical remission, and CSF leaks remain hard to predict, but machine learning offers potential in helping to tailor surgical therapy. We demonstrate the feasibility of developing and externally validating clinical prediction models for these outcomes after surgery for acromegaly and lay the groundwork for development of a multicenter model with more robust generalization

DOPAL initiates αSynuclein-dependent impaired proteostasis and degeneration of neuronal projections in Parkinson’s disease

Dopamine dyshomeostasis has been acknowledged among the determinants of nigrostriatal neuron degeneration in Parkinson’s disease (PD). Several studies in experimental models and postmortem PD patients underlined increasing levels of the dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is highly reactive towards proteins. DOPAL has been shown to covalently modify the presynaptic protein αSynuclein (αSyn), whose misfolding and aggregation represent a major trait of PD pathology, triggering αSyn oligomerization in dopaminergic neurons. Here, we demonstrated that DOPAL elicits αSyn accumulation and hampers αSyn clearance in primary neurons. DOPAL-induced αSyn buildup lessens neuronal resilience, compromises synaptic integrity, and overwhelms protein quality control pathways in neurites. The progressive decline of neuronal homeostasis further leads to dopaminergic neuron loss and motor impairment, as showed in in vivo models. Finally, we developed a specific antibody which detected increased DOPAL-modified αSyn in human striatal tissues from idiopathic PD patients, corroborating the translational relevance of αSyn-DOPAL interplay in PD neurodegeneration