Modifications of geldanamycin via CuAAC altering affinity to chaperone protein Hsp90 and cytotoxicity.

Functionalization of alkyne (1) and azide (2) derivatives of geldanamycin (GDM) via dipolar cycloaddition CuAAC yielded 35 new congeners (3-37) with C(17)-triazole arms bearing caps of different nature (basic vs. acidic, hydrophilic vs. hydrophobic). Confrontation of biological data (anticancer activity vs. toxicity in normal cells) with lipophilicity (clogP), dissociation constants (Kd) of complexes with Hsp90 and binding modes to Hsp90 revealed SAR in specific subgroups of GDM derivatives. The most potent GDM congeners 14-16, bearing C(17)-triazole-benzyl-halogen arms exhibited the most optimal clogP values of 2.7-3.1 at favourable binding to Hsp90 (KdHsp90 at µM level). The anticancer activity of 14-16 (IC50 = 0.23-0.41 µM) is higher than those of GDM (IC50 = 0.58-0.64 µM) and actinomycin D (ActD, IC50 = 0.62-0.71 µM) in SKBR-3, SKOV-3 and PC-3 cell lines, with a comparable cytotoxicity in healthy cells. The relationship between structure and attractive anticancer potency (IC50 = 0.53-0.74 µM) is also observed for congeners with C(17)-triazole-saccharide or C(17)-triazole-unsaturated arms. In the former, the absolute configuration at C(4) (ᴅ-glucose vs. ᴅ-galactose) whereas in the latter the length of the unsaturated arm influences the cytotoxic effects due to different binding strength (Kd, ΔE) and modes with Hsp90. Among all triazole congeners of GDM that are biologically attractive and exhibit lower toxicity in normal cells than GDM and ActD, the derivative 22, bearing the C(17)-triazole-cinnamyl arm, shows the lowest Kd (Hsp90), optimal clogP = 2.82, the best pro-apoptotic properties in SKBR-3 and SKOV-3 and the best selectivity indices (SI). For the most potent GDM derivatives with C(17)-triazole arm, the docking studies have suggested the importance of the intermolecular stabilization between the arm and the D57 or Y61 of Hsp90.

Central Nervous System Progression in Primary Vitreoretinal Lymphoma with Bilateral and Unilateral Involvement: A Systematic Review and Meta-Analysis.

BACKGROUND: Primary vitreoretinal lymphoma (PVRL) is either unilateral or bilateral at initial presentation. Progression to a central nervous system (CNS) lymphoma is regularly observed and these patients seem to have an inferior survival. Knowledge of the predictive value of laterality for CNS progression may facilitate risk stratification and the development of more effective treatment strategies, and eventually, improve outcomes. The objective of this analysis is to estimate the risk of CNS progression for patients with bilateral versus unilateral involvement of PVRL. METHODS: Systematic literature search for studies on CNS progression in PVRL with bilateral and unilateral involvement according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We assessed the risk of bias and the methodological quality of studies using the Quality in Prognosis Studies (QUIPS) tool. Risk ratios of CNS progression in PVRL with bilateral and unilateral involvement were calculated and combined via a meta-analysis. RESULTS: Twenty-five small-sized (total n = 371 cases) studies were included. The majority of the studies were at medium to high risk of bias. Results suggest no significant difference in CNS progression between bilateral and unilateral PVRL, with a pooled relative risk ratio of 1.12 (95% confidence interval 0.89-1.41). CONCLUSIONS: CNS progression is common in PVRL. From the limited available evidence, there is no significant difference in CNS progression between bilateral and unilateral PVRL.

Novel approaches for treating Internet Gaming Disorder: A review of technology-based interventions.

Internet Gaming Disorder (IGD) has become a significant issue in mental healthcare over the past decades as the number of people engaging in excessive and unhealthy gaming increases with each year. Despite its inclusion in the 5th Edition of Diagnostic Statistical Manual and the development of a number of treatment methods that have been designed and tested for IGD, treatment remains a challenge. This review attempts to give an overview of the current state of IGD and its treatment with a specific focus on the potential of technology-based solutions, such as web-based programs, mobile applications, and virtual reality. The review also highlights the need for additional work in the area of treatment development for IGD and the preliminary evidence for the usefulness and importance of technology-based treatment methods which offer unique advantages, such as accessibility, scalability, and cost-effectiveness, over other existing treatment options.

Facile production of ultra-fine silicon nanoparticles.

A facile procedure for the synthesis of ultra-fine silicon nanoparticles without the need for a Schlenk vacuum line is presented. The process consists of the production of a (HSiO1.5) n sol-gel precursor based on the polycondensation of low-cost trichlorosilane (HSiCl3), followed by its annealing and etching. The obtained materials were thoroughly characterized after each preparation step by electron microscopy, Fourier transform and Raman spectroscopy, X-ray dispersion spectroscopy, diffraction methods and photoluminescence spectroscopy. The data confirm the formation of ultra-fine silicon nanoparticles with controllable average diameters between 1 and 5 nm depending on the etching time.

In Situ Formation of Free-Standing Single-Atom-Thick Antiferromagnetic Chromium Membranes.

Compared to van der Waals two-dimensional (2D) layers with lateral covalent bonds, metallic bonding systems favor close-packed structures, and thus, free-standing 2D metals have remained, for the most part, elusive. However, a number of theoretical studies suggest a number of metals can exist as 2D materials and a few early experiments support this notion. Here we demonstrate free-standing single-atom-thick crystalline chromium (Cr) suspended membranes using aberration-corrected transmission electron microscopy and image simulations. Density functional theory studies confirm the 2D Cr membranes have an antiferromagnetic ground state making them highly attractive for spintronic applications. Moreover, the work also helps consolidate the existence of a new family of 2D metal layers.