[The role and application of high-throughput screening in the search for chemical compounds of therapeutic activity].

With the development of medicine and the aging population, the demand for more effective therapies is escalating. A tool that facilitates the discovery and introduction of new therapeutic drugs is High-Throughput Screening (HTS). These tests, consisting of a wide set of various assays, allow testing hundreds of thousands of compounds in a short period of time.

[Multi-analyte responsive luminescent probes for the detection of biochemical targets in cell models].

Luminescence has found wide application in biology, biotechnology and medicine. Particularly, fluorescent and bioluminescent probes allow visualization of molecular targets at the cellular level and even macromolecules or single small-molecule analytes. Among the most reliable tools for visualization of molecular targets are so-called responsive probes, which change the intensity and colour of the emitted signal after interaction with a molecular target.

Tetramethylalloxazines as efficient singlet oxygen photosensitizers and potential redox-sensitive agents.

Tetramethylalloxazines (TMeAll) have been found to have a high quantum yield of singlet oxygen generation when used as photosensitizers. Their electronic structure and transition energies (S → S, S → T, T → T) were calculated using DFT and TD-DFT methods and compared to experimental absorption spectra. Generally, TMeAll display an energy diagram similar to other derivatives belonging to the alloxazine class of compounds, namely π,π* transitions are accompanied by closely located n,π* transitions.

5-Deazaalloxazine as photosensitizer of singlet oxygen and potential redox-sensitive agent.

Flavins are a unique class of compounds that combine the features of singlet oxygen generators and redox-dependent fluorophores. From a broad family of flavin derivatives, deazaalloxazines are significantly underdeveloped from the point of view of photophysical properties. Herein, we report photophysics of 5-deazaalloxazine (1a) in water, acetonitrile, and some other solvents.

Intracellular flow cytometric lipid analysis - a multiparametric system to assess distinct lipid classes in live cells.

The lipid content of mammalian cells varies greatly between cell type. Current methods for analysing lipid components of cells are technically challenging and destructive. Here, we report a facile, inexpensive method to identify lipid content - intracellular flow cytometric lipid analysis (IFCLA).

Microwave-Assisted Catalytic Method for a Green Synthesis of Amides Directly from Amines and Carboxylic Acids.

Amide bonds are among the most interesting and abundant molecules of life and products of the chemical pharmaceutical industry. In this work, we describe a method of the direct synthesis of amides from carboxylic acids and amines under solvent-free conditions using minute quantities of ceric ammonium nitrate (CAN) as a catalyst. The reactions are carried out in an open microwave reactor and allow the corresponding amides to be obtained in a fast and effective manner when compared to other procedures of the direct synthesis of amides from acids and amines reported so far in the literature.

Respiratory syncytial virus co-opts host mitochondrial function to favour infectious virus production.

Although respiratory syncytial virus (RSV) is responsible for more human deaths each year than influenza, its pathogenic mechanisms are poorly understood. Here high-resolution quantitative imaging, bioenergetics measurements and mitochondrial membrane potential- and redox-sensitive dyes are used to define RSV's impact on host mitochondria for the first time, delineating RSV-induced microtubule/dynein-dependent mitochondrial perinuclear clustering, and translocation towards the microtubule-organizing centre. These changes are concomitant with impaired mitochondrial respiration, loss of mitochondrial membrane potential and increased production of mitochondrial reactive oxygen species (ROS).

Evidence for Reagent-Induced Spin-State Switching in Tripodal Fe(II) Iminopyridine Complexes.

We present evidence of a spin-state change that accompanies desilylation reactions performed on two related Fe(II) iminopyridine coordination complexes. To probe these systems, we performed titrations with CsF in solution and analyzed the speciation with in situ magnetometry, electrochemistry, and mass spectrometry techniques. We find that pendant tert-butyldimethylsilyl groups are readily cleaved under these conditions, and the resulting desilylated complexes exhibit overall decreased solution magnetic susceptibility values.

Drawing on biology to inspire molecular design: a redox-responsive MRI probe based on Gd(iii)-nicotinamide.

A novel, reversible redox-active MRI probe, GdNR1, has been developed for the study of redox changes associated with diseased states. This system exhibits switching in relaxivity upon reduction and oxidation of the appended nicotinimidium. Relaxivity studies and cyclic voltammetry confirmed the impressive reversibility of this system, at a biologically-relevant reduction potential.

A reversible fluorescent probe for monitoring Ag(I) ions.

Silver-containing nanomaterials are of interest for their antibiotic properties, for a wide range of applications from medicine to consumer products. However, much remains to be learnt about the degradation of such materials and their effects on human health. While most analyses involve measurement of total silver levels, it is important also to be able to measure concentrations of active free Ag(I) ions.

A ratiometric iron probe enables investigation of iron distribution within tumour spheroids.

Iron dysregulation is implicated in numerous diseases, and iron homeostasis is profoundly influenced by the labile iron pool (LIP). Tools to easily observe changes in the LIP are limited, with calcein AM-based assays most widely used. We describe here FlCFe1, a ratiometric analogue of calcein AM, which also provides the capacity for imaging iron in 3D cell models.

Pro-fluorescent mitochondria-targeted real-time responsive redox probes synthesised from carboxy isoindoline nitroxides: Sensitive probes of mitochondrial redox status in cells.

Here we describe new fluorescent probes based on fluorescein and rhodamine that provide reversible, real-time insight into cellular redox status. The new probes incorporate bio-imaging relevant fluorophores derived from fluorescein and rhodamine linked with stable nitroxide radicals such that they cannot be cleaved, either spontaneously or enzymatically by cellular processes. Overall fluorescence emission is determined by reversible reduction and oxidation, hence the steady state emission intensity reflects the balance between redox potentials of critical redox couples within the cell.

Fluorescent probes for the simultaneous detection of multiple analytes in biology.

Many of the key questions facing cellular biology concern the location and concentration of chemical species, from signalling molecules to metabolites to exogenous toxins. Fluorescent sensors (probes) have revolutionised the understanding of biological systems through their exquisite sensitivity to specific analytes. Probe design has focussed on selective sensors for individual analytes, but many of the most pertinent biological questions are related to the interaction of more than one chemical species.

A Carborane-Containing Fluorophore as a Stain of Cellular Lipid Droplets.

The use of fluorescent markers and probes greatly enhances biological investigations but relies on the provision of an array of fluorophores with diverse properties. Herein we report a novel carborane-containing coumarin, 5, which is sufficiently lipophilic to localise in cellular lipid droplets. In non-polar solvents which show comparable polarities to those of a lipid environment, compound 5 exhibits a fluorescence quantum yield two orders of magnitude greater than found in aqueous solvents, adding a further degree of selectivity to lipid droplet imaging.

Mitochondrially targeted fluorescent redox sensors.

The balance of oxidants and antioxidants within the cell is crucial for maintaining health, and regulating physiological processes such as signalling. Consequently, imbalances between oxidants and antioxidants are now understood to lead to oxidative stress, a physiological feature that underlies many diseases. These processes have spurred the field of chemical biology to develop a plethora of sensors, both small-molecule and fluorescent protein-based, for the detection of specific oxidizing species and general redox balances within cells.

A cobalt(ii) complex with unique paraSHIFT responses to anions.

ParaSHIFT agents have shown promise in detecting chemical targets in biological systems by magnetic resonance, but few studies have used transition metal complexes for this purpose. Here we report our investigations into CoMetrenCl (tren = tris(2-aminoethyl)amine) as a paraSHIFT agent. The paramagnetic region of the H NMR spectrum shows characteristic spectral profiles in the presence of fluoride, acetate, lactate and citrate in aqueous solution.

A ratiometric fluorescent sensor for the mitochondrial copper pool.

Copper plays a key role in the modulation of cellular function, defence, and growth. Here we present InCCu1, a ratiometric fluorescent sensor for mitochondrial copper, which changes from red to blue emission in the presence of Cu(i). Employing this probe in microscopy and flow cytometry, we show that cisplatin-treated cells have an impaired ability to accumulate copper in the mitochondria.

Reversible Fluorescent Probes for Biological Redox States.

The redox chemistry of the cell is key to its function and health, and the development of chemical tools to study redox biology is important. While fluxes in oxidative state are essential for healthy cell function, a chronically elevated oxidative capacity is linked to disease. It is therefore essential that probes of biological redox states distinguish between these two conditions by the reversible sensing of changes over time.

Selective and Reversible Approaches Toward Imaging Redox Signaling Using Small-Molecule Probes.

Significance: Recent research has identified key roles for reactive oxygen species (ROS)/reactive nitrogen species (RNS) in redox signaling, but much remains to be uncovered. Molecular imaging tools to study these processes must not only be selective to enable identification of the ROS/RNS involved but also reversible to distinguish signaling processes from oxidative stress. Fluorescent sensors offer the potential to image such processes with high spatial and temporal resolution.

Magnetogenesis in water induced by a chemical analyte.

This Minireview aims to shed light on the emergent field of inducing a change in the magnetic properties of a solution-phase sample by exposing it to a chemical analyte. A considerable body of knowledge exists on materials that alter their magnetic characteristics after a change in the surrounding physical conditions and a number of cases even exist of solution-phase samples that do so under these same circumstances. However, examples of dissolved molecules or particles that react in this fashion under constant conditions and in response to an analyte are limited.

Bispidine platform grants full control over magnetic state of ferrous chelates in water.

A bicyclic ligand platform for iron(II), which allows total control over the complex's magnetic properties in aqueous solution simply by varying one of the six coordination sites of the bispidine ligand, is reported. To achieve this, an efficient synthetic route to an N5 bispidine framework (ligand L4) that features an unsubstituted N-7 site is established. Then, by choosing appropriate N-7-coordinating substituents, the spin state of choice can be imposed on the corresponding ferrous complexes under environmentally relevant conditions in water and near-room temperature.

Dietary cassava, beta-cell function and hyperbolic product loss rate in type 2 diabetes patients from South Kivu.

Objective: Cassava, a major carbohydrate source in Africa, contains potentially diabetogenic chemicals, although its consumption is not associated with incident diabetes. As it is not known whether cassava intake impairs residual beta-cell function in patients with type 2 diabetes (T2D), our study compared the metabolic phenotypes of diet- and/or oral antidiabetic drug (OAD)-treated T2D patients in South Kivu (Democratic Republic of the Congo) with [Cassava (+); n=147] and without [Cassava (-); n=46] self-reported cassava consumption.

Design & Methods: A total of 193 patients [male:female (%) 37:63; mean +/-1 SD age: 56+/-11 years] were interviewed to determine the frequency and distribution of eight major dietary carbohydrate (CHO) sources (cassava, plantain, rice, maize, bread, sorghum, potatoes and legumes).

The effects of orlistat on weight and on serum lipids in obese patients with hypercholesterolemia: a randomized, double-blind, placebo-controlled, multicentre study.

Objective: Assessment of the effects of orlistat 120 mg three times daily vs placebo on weight loss and serum lipids in obese hypercholesterolemic patients.

Design: A 24 week multicentre, double-blind, randomized, placebo-controlled trial. After a 2-week single-blind run-in period (placebo+diet (-600 kcal/day; < or =30% of calories as fat)), 294 patients were submitted to the hypocaloric diet and randomly assigned to either orlistat 120 mg or placebo three times daily.