Secondary amines can be readily oxidized to the corresponding nitrones using urea-hydrogen peroxide complex (UHP) and metal catalysts in methanol at room temperature. Sodium tungstate is the most ...effective catalyst in several runs and common protecting groups are tolerated in these conditions.
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The extraction of glycyrrhizin from licorice root and stolon with ethanol/water solutions leaves a lignocellulosic residue, which could be potentially applied in biocomposites. This process proved ...difficult in principle, given the considerable hardness of this material as received, which impedes its use in polymer resins in large amounts. After ball milling, up to 10% of this fibrous residue, which shows very variable aspect ratio, was introduced into an epoxy matrix, to investigate its possible future application in sustainable polymers. Of the three composites investigated, containing 1, 5 and 10 wt% of licorice waste, respectively, by performing flexural testing, it was found that the introduction of an intermediate amount of filler proved the most suitable for possible development. Thermal characterization by thermogravimetry (TGA) did not indicate large variation of degradation properties due to the introduction of the filler. Despite the preliminary characteristics of this study, an acceptable resin-filler interface has been obtained for all filler contents. Issues to be solved in future study would be the possibility to include a larger amount of filler by better compatibilization and a more uniform distribution of the filler, considering their orientation, since most of it maintains an elongated geometry after ball milling.
Climacostol, a compound produced by the ciliated protozoan Climacostomum virens, displayed cytotoxic properties in vitro. This study demonstrates that it has anti-tumour potential. Climacostol caused ...a reduction of viability/proliferation of B16-F10 mouse melanoma cells, a rapidly occurring DNA damage, and induced the intrinsic apoptotic pathway characterised by the dissipation of the mitochondrial membrane potential, the translocation of Bax to the mitochondria, the release of Cytochrome c from the mitochondria, and the activation of Caspase 9-dependent cleavage of Caspase 3. The apoptotic mechanism of climacostol was found to rely on the up-regulation of p53 and its targets Noxa and Puma. In vivo analysis of B16-F10 allografts revealed a persistent inhibition of tumour growth rate when melanomas were treated with intra-tumoural injections of climacostol. In addition, it significantly improved the survival of transplanted mice, decreased tumour weight, induced a remarkable reduction of viable cells inside the tumour, activated apoptosis and up-regulated the p53 signalling network. Importantly, climacostol toxicity was more selective against tumour than non-tumour cells. The anti-tumour properties of climacostol and the molecular events associated with its action indicate that it is a powerful agent that may be considered for the design of pro-apoptotic drugs for melanoma therapy.
Am 7. Februar 2020 verstarb Giuseppe Bartoli nach kurzer Krankheit. Der herausragende Chemiker hinterlässt ein eindrucksvolles Werk auf dem Gebiet der organischen Synthese. Sein Freunde betrauern ...einen unwiederbringlichen Verlust.
Abstract
Purpose:
this study was conducted to evaluate longterm results following treatment of chronic lateral ankle instability using the Broström-Gould technique in athletes.
Methods:
eighteen ...athletes involved in competitive sports at different levels, who suffered from chronic lateral ankle instability, underwent Broström-Gould ligamentoplasty between 2000 and 2005. The results of the surgery were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) scale.
Results:
the results at 10-15 years of follow-up were excellent in 94.5% of these cases and good in the remaining 5.5%. An increase of 31.2 points in the AOFAS scale score was recorded at follow-up (with the score rising to 98.8, from 67.6 preoperatively). All the athletes returned to their respective sports at the same level as prior to the surgery. Imaging at longterm follow-up showed no signs of arthritic degeneration.
Conclusions:
the results of this study show that the Broström-Gould technique is an effective procedure for the treatment of chronic lateral ankle instability in the athlete, giving excellent long-term results.
Level of evidence:
therapeutic case series, level IV.
A new procedure for the sulfenylation of indoles and pyrroles based on an aromatic substitution with alpha-acylthiones used as electrophiles is described. The sulfenylating species were obtained, ...under very mild reaction conditions, from N-thiophthalimides, using a weak base (pyridine or triethylamine) as promoter. The overall yields obtained are comparable with those obtained by other known sulfenylation protocols, which typically require harsher reaction conditions and/or metal-containing Lewis acids as promoters.
•The protozoan toxin climacostol exerts prooxidant activity in the presence of Cu(II) ions.•Climacostol binds to DNA.•The prooxidant activity can damage plasmid and eukaryotic DNA.
Climacostol is a ...natural toxin isolated from the freshwater ciliated protozoan Climacostomum virens and belongs to the group of resorcinolic lipids. Climacostol exerts a potent antimicrobial activity against a panel of bacterial and fungal pathogens. In addition it inhibits the growth of tumor cell lines in a dose-dependent manner by inducing programmed cell death via intrinsic pathway. In this work, we investigated the possibility that climacostol exerts a prooxidant effect, inducing plasmid DNA strand breakage and eukaryotic DNA damage in presence of Cu(II) ions. Inhibition of DNA breakage using SOD, catalase and neocuproine confirmed the involvement of reactive oxygen species and Cu(I) ions in the DNA damage. UV–visible absorption changes and mass spectrometric analysis identified a product of reaction as a deprotonated form of climacostol. Study of the interaction with DNA, using fluorescence spectroscopic techniques, showed that climacostol binds with DNA. Given the structure–activity relationship of this compound and the mechanism of its prooxidant effect, we propose that the Cu(II)-mediated oxidative DNA damage by climacostol could explain its antimicrobial and antiproliferative activity.
► Peach cultivars were screened for medfly tolerance in laboratory and field tests. ► The cultivars Doctor Davis and Percoca Romagnola 7 resulted particularly tolerant. ► Peach volatile profiles of ...tolerant and susceptible cultivars were compared. ► C6 esters were found mainly in the tolerant cv Percoca Romagnola 7. ► Some methyl esters, known to be fly pheromones, were scarce in tolerant cultivars.
The relationship between susceptibility of different peach cultivars (cvs) to the Mediterranean fruit fly (medfly), Ceratitis capitata, and the volatile composition of ripe fruit of each cv has been investigated, since understanding the fruit-insect interaction mechanism is crucial for developing control strategies for such a pest. Volatile compounds were analyzed by SPME–GC–MS in three cvs highly susceptible to medfly attack (Fair Time, Flaminia, Sicilia Piatta), and in two less susceptible cvs (Percoca Romagnola 7 and Doctor Davis). Among the volatile compounds detected, 88 could be identified. The main differences found in the volatile composition of the cvs, concerned the relative abundance of esters. The least susceptible cvs, above all Percoca Romagnola 7, contained the higher amounts of hexenyl, hexyl, 3-methylbutyl, butyl and 2-methylpropyl esters; among these, some C6 derivatives detected, such as (Z)-3-hexenyl acetate, are known to act as priming agents, enhancing plant defence response to insects. Instead, a lower relative content of methyl esters, such as methyl hexanoate and methyl octanoate, known to act as medfly pheromone and attractant respectively, was found in the least susceptible cvs.
The ciliate Climacostomum virens produces the metabolite climacostol that displays antimicrobial activity and cytotoxicity on human and rodent tumor cells. Given its potential as a backbone in ...pharmacological studies, we used the fruit fly Drosophila melanogaster to evaluate how the xenobiotic climacostol affects biological systems in vivo at the organismal level. Food administration with climacostol demonstrated its harmful role during larvae developmental stages but not pupation. The midgut of eclosed larvae showed apoptosis and increased generation of reactive oxygen species (ROS), thus demonstrating gastrointestinal toxicity. Climacostol did not affect enteroendocrine cell proliferation, suggesting moderate damage that does not initiate the repairing program. The fact that climacostol increased brain ROS and inhibited the proliferation of neural cells revealed a systemic (neurotoxic) role of this harmful substance. In this line, we found lower expression of relevant antioxidant enzymes in the larvae and impaired mitochondrial activity. Adult offsprings presented no major alterations in survival and mobility, as well the absence of abnormal phenotypes. However, mitochondrial activity and oviposition behavior was somewhat affected, indicating the chronic toxicity of climacostol, which continues moderately until adult stages. These results revealed for the first time the detrimental role of ingested climacostol in a non-target multicellular organism.
Poly(methyl methacrylate) (PMMA)/clay nanocomposites (NCs) were prepared by suspension polymerization of methyl methacrylate in the presence of two different organoclays (Cloisite 30B, Cloisite 15A) ...with clay loading ranged from 0.5 to 5 wt%. Increase in molecular weight of the PMMA matrix with addition of the clay was revealed by gel permeation chromatography (GPC) and intrinsic viscosity measurements. As confirmed by X-ray diffraction (XRD), the NCs had an intercalated structure. The organoclays-MMA/PMMA compatibility was investigated by swelling tests and solubility parameter approach. Rheological behavior of PMMA NCs in molten state was analyzed through construction of master curves of complex viscosity, storage, and loss modulus by applying the time–temperature superposition procedure. Melt rheology, scanning electron microscopy (SEM), and UV/Vis spectroscopy results confirmed higher extent of clay dispersion in the NCs with Cloisite 30B. Compared to pure PMMA, all these NCs show increase of glass transition temperature as measured by DSC and improved thermal stability determined by thermogravimetric analysis (TGA). The results obtained by dynamic mechanical analysis showed that the storage modulus of the NCs was higher by incorporation of clay into the PMMA matrix, increasing as the amount of clay increased and that their mechanical performance was significantly enhanced.
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