1,721,042 research outputs found
Implementation of an iterative approach to optimize synchrotron X-ray fluorescence quantification of light elements in single cell
No full textA new approach for elemental quantification and error estimation in single cells, named Single Cell Elemental Quantification Iterative Approach (SCEQIA), has been performed merging two analytical approaches conceptually different. The first one is a multimodal approach designed to identify and quantify the concentration of light elements in biological samples and to calculate errors following error propagation law. The second one is an iterative algorithm conceived to quantify heavy elements in terms of mass fraction in mineral samples and to evaluate errors using an iterative Monte Carlo-based procedure. The fluorescence data and scanning transmission data, provided by synchrotron X-ray microscopic techniques, together with the volumetric data from Atomic Force Microscopy (AFM) of two colon carcinoma cells have been analyzed following SCEQIA approach. The mass fraction and the molar concentration of the elements C, N, O, Na, and Mg have been mapped. The obtained results have been compared with those previously provided with the original multimodal approach above mentioned. The outputs of the two approaches are comparable in terms of elemental quantification (mass fraction and concentration) for both the analyzed samples. On the contrary, the two approaches differ in error estimation: the newly developed SCEQIA approach results less influenced by the uncertainties of AFM measurements
Cytotoxic Effects of Artemisia annua L. and Pure Artemisinin on the D-17 Canine Osteosarcoma Cell Line
Full text linkArtemisia annua has been used for centuries in Traditional Chinese Medicine. Although used as an antimalarial drug, its active compound artemisinin and the semisynthetic derivatives have also been investigated for their anticancer properties, with interesting and promising results. The aims of this research were to evaluate (i) the cytotoxicity and the antiproliferative effect of pure artemisinin and a hydroalcoholic extract obtained from A. annua on the D-17 canine osteosarcoma cell line and (ii) the intracellular iron concentration and its correlation with the cytotoxic effects. Both artemisinin and hydroalcoholic extract induced a cytotoxic effect in a dose-dependent manner. Pure artemisinin caused an increase of cells in the S phase, whereas the hydroalcoholic extract induced an evident increase in the G2/M phase. A significant decrease of iron concentration was measured in D-17 cells treated with pure artemisinin and hydroalcoholic extract compared to untreated cells. In conclusion, although preliminary, the data obtained in this study are indicative of a more potent cytotoxic activity of the hydroalcoholic extract than pure artemisinin, indicating a possible synergistic effect of the phytocomplex and a mechanism of action involving iron and possibly ferroptosis. Considering the similarities between human and canine osteosarcomas, progress in deepening knowledge and improving therapeutic protocols will probably be relevant for both species, in a model of reciprocal translational medicine
Development of azithromycin-loaded microemulsions for the treatment of skin infections
No full textIn the recent years bacterial skin infections have been considered one of the major healthcare issues due to the growing emergence of antibiotic-resistant strains of Staphylococcus aureus [1]. Topical application of currently approved antibiotics represents the first strategy for the treatment of skin infections. However, the poor drug retention within the skin can lead to an insufficient drug concentration at the action site and consequently multiple and frequent administrations are generally required, thus impairing patient compliance. In this context, the design of new drug delivery systems useful to improve the treatment of skin infections still remains a challenge of growing urgency [2]. Therefore, the aim of this work was to develop microemulsions containing azithromycin (AZT), a broad-spectrum macrolide antibiotic, for advanced treatment of antibiotic-resistant bacterial infections of the skin.
AZT solubility in various oils, surfactants and co-surfactants was firstly assessed to select the main components of the microemulsions. Then, microemulsions composed of different amounts of vitamin E acetate, Labrasol®, Transcutol® P and water were prepared and characterized for their pH, viscosity, droplet size, zeta potential, stability over a storage period of 180 days, ability to release the drug and to promote its retention inside porcine skin. Antimicrobial activity and biocompatibility of microemulsions were also evaluated.
Microemulsions showed pH values (around 4.5) in the acceptable pH range of the skin and were characterized by different droplet size (97-138 nm) and viscosity (24-36 mPa*s) depending on their composition. Moreover, the selected microemulsions showed negative zeta potential values (from -22 to -28 mV) which contributed to microemulsion stability over the storage period. Interestingly, all the developed microemulsions provided a prolonged release of AZT, useful to achieve a suitable local drug concentration over the time. Furthermore, microemulsions promoted drug accumulation inside the skin with respect to the control, as consequence of their droplet size, superficial charge and composition. Particularly, microemulsion M1 (vitamin E acetate, Labrasol®, Transcutol® and water 7.7:40.1:18.7:33.5 w/w/w) allowed the retention of a high percentage of drug (46.69 ± 7.96 %) inside the porcine skin, was not cytotoxic and maintained AZT efficacy on S. aureus methicillin-resistant strains. Hence, the developed AZT-loaded microemulsion could be considered a promising tool for topical treatment of skin infections
Basement Membrane, Collagen, and Fibronectin: Physical Interactions with Cancer Cells
No full textCancer cell invasion is regulated by extracellular matrix (ECM) chemical signaling and gene expression but it also consists in a mechanical process controlled by ECM’s array. Scanning electron microscope analysis, invasion test, and real-time PCR demonstrated that Matrigel mimicking basement membrane (BM) doesn’t promote epithelial–mesenchymal transition (EMT) in both low and very aggressive breast cancer cells (MCF-7 and MDA-MB-231). A loose network of type I collagen mimicking the sub-BM favors EMT in MCF-7 cells but physically limits their invasion ability vs. Matrigel, as collagen does not induce an increase of metalloproteases (MMPs) in cells following ameboid-invasion mode. Collagen doesn’t change MDA-MB-231 phenotypes but further improves their invasion capability vs. Matrigel, by stimulating MMPs production. Concentrated type I collagen mimicking deeper ECM induces cells adhesion, further development of microvesicles, microvilli, long filopodia, and tunneling nanotubes (TNTs). Nonaligned fibronectin favors breast cancer cells adhesion, microvesicles, and TNTs development. Densely packed and parallel collagen fibers mimicking a collagen array in mammary tumor progression oppose invasion. In colon cancer, LoVo-R cells, resistant to doxorubicin, concentrated collagen favors development of invaginating phenotypes with invadopodia. We suggest that collagen acts as a physical factor inducing EMT in breast cancer cells and drug resistance in LoVo-R cells
p53-dependent and p53-independent anticancer activity of a new indole derivative in human osteosarcoma cells
No full textFluorescence lifetime imaging of intracellular magnesium content in live cells
Full text linkThe first detailed analysis of FLIM applications for Mg cell imaging is presented. We employed the Mg-sensitive fluorescent dye named DCHQ5, a derivative of diaza-18-crown-6 ethers appended with two 8-hydroxyquinoline groups, to perform fluorescence lifetime imaging in control and Mg deprived SaOS-2 live cells, which contain different concentrations of magnesium. We found that the lifetime maps are almost uniform all over the cells and, most relevantly, we showed that the ratio of the amplitude terms is related to the magnesium intracellular concentration
Where is it and how much? Mapping and quantifying elements in single cells
No full textThe biological function of a chemical element in cells not only requires the determination of its intracellular quantity, but also the spatial distribution of its concentration. Different strategies can be employed to quantify and map the intracellular concentration of elements in single cells. The assessment of the intracellular elemental concentration, which is the relevant information, requires the measurement of cell volume. This challenging and demanding task requires combining different techniques allowing gathering of both morphological and compositional information on the same cell. Moreover, the need to analyse samples more similar to their natural state requires complex hardware equipment, and supplementary efforts in preparation protocols. Nevertheless, the response to the question: "where is it and how much?" is worth all these efforts. This review aims at providing an insight into the recent and most advanced techniques and strategies for quantifying and mapping chemical elements in single cells. We describe and discuss indirect detection techniques (label based) which make use of fluorescent dyes, and direct ones (label free), such as particle induced X-ray emission, proton backscattering spectrometry, scanning transmission ion spectrometry, nano-secondary ion mass spectrometry, X-ray fluorescence microscopy, complemented by X-ray imaging
Nutrients and Nutraceuticals from Vitis vinifera L. Pomace: Biological Activities, Valorization, and Potential Applications
Full text linkGrape pomace, also known as wine pomace, is a by-product of winemaking that has traditionally been discarded. However, recent studies have highlighted its rich nutritional and bioactive potential, positioning it as a promising resource for various applications in the functional food, pharmaceutical, and cosmetic sectors. This review explores the nutrient and nutraceutical contents of grape pomace, including its high levels of polyphenols, dietary fiber, vitamins, minerals, and melatonin. The biological activities of grape pomace, such as antioxidant, anti-inflammatory, antimicrobial, and anticancer effects, are also discussed, emphasizing its potential as raw material endowed with multifunctional properties. Additionally, the valorization of grape pomace as a food supplement and for the development of cosmetics is examined, focusing on its incorporation into dietary products and skincare formulations. The growing interest in the sustainable utilization of grape pomace is underscored, highlighting its significant role in promoting human health and contributing to a circular economy
Monitoring magnesium efflux cyclic AMP-induced in HL60 cells by using a new hydroxyquinoline fluorescent chemosensor
No full textCellular homeostasis of magnesium is still unclear. Several studies documented the occurrence of fluxes of magnesium across the plasmamembrane within minutes from the application of metabolic or hormonal stimuli. These fluxes, however, result in limited variation of free Mg2+ intracellular concentration and large changes in total Mg content. It has been reported that a stimulation with cyclic AMP caused a movement of total magnesium within 10 min after treatment in cardiomyocytes. In this study we tested this hypothesis in HL60 leukemic cells, not excitable but highly proliferating cell model. We evaluated Mg flux by DCHQ5, the phenyl-derivative of hydroxyquinoline fluorescent probe family. We observed a drastic decrease of intracellular total magnesium in the first 3 min. We also verified that at least 10% of the total intracellular amount of magnesium moved in the supernatant of stimulated cells
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