Palladium(II)-directed self-assembly of a neutral molecular triangle as a heteroditopic receptor for ion pairs.

A molecular triangle, based on the self-assembly of 4,7-phenanthroline by a neutral palladium complex, has been synthesized and characterized by a combination of techniques: (1)H NMR and UV-vis absorption spectroscopies, mass spectrometry, elemental analysis, and gel permeation chromatography. This new neutral metallocavitand has demonstrated the capacity to host both anionic and cationic guests, thus acting as an open-shaped heteroditopic receptor. Density functional theory calculations have shown that (i) there is no overtension in the assembly of the discrete triangle, which is more stable than open-chain oligomers, (ii) the adducts formed between the triangle and some salts (modeled in the gas phase) are thermodynamically stable, and (iii) two types of cavities coexist in the triangle, which host ions and ion pairs. This easily accessible triangular unit extends further the rational design of model nanoarchitectures in host-guest chemistry with applications in analytical chemistry and multifunctional molecular materials.

Plasma Endocannabinoid Alterations in Individuals with Substance Use Disorder are Dependent on the "Mirror Effect" of Schizophrenia.

Schizophrenia is a complex psychiatric disorder strongly associated with substance use disorders. Theoretically, schizophrenia and SUD may share endocannabinoid alterations in the brain reward system. The main endocannabinoids, anandamide, and 2-arachidonoylglycerol, are lipids which bind cannabinoid receptors. Oleoylethanolamide (OEA), a fatty-acid ethanolamide, binds peroxisome proliferator-activated receptors. The endocannabinoid system has been shown to be impaired in schizophrenia, and recently, our group has shown that schizophrenia patients with SUD have elevated peripheral levels of anandamide and OEA that do not normalize after 3-month treatment with quetiapine. Objective For comparative purposes, we aimed to measure endocannabinoids in non-psychosis substance abusers and non-abusing schizophrenia patients. Methods Using liquid chromatography and mass spectrometry, we measured plasma levels of anandamide and OEA in non-psychosis SUD patients, non-abusing schizophrenia patients, and healthy controls. In an open-label manner, all patients received 12-week treatment with quetiapine. Results Anandamide and OEA were reduced in substance abusers without schizophrenia, relative to healthy controls (p < 0.05). Both endocannabinoids were unchanged in non-abusing schizophrenia patients. After quetiapine, anandamide, and OEA levels remained significantly reduced the SUD group (p < 0.05). Discussion Taken together with results of our previous study performed in dual-diagnosis patients, our results suggest that peripheral anandamide and OEA levels are impaired in patients with SUD in opposite ways according to the presence or absence of schizophrenia. Endocannabinoid alterations did not change with treatment, suggesting that they are trait markers. Further studies are necessary to understand the role of endocannabinoids in substance abusers with and without schizophrenia and to examine therapeutic implications.

Coordination-driven self-assembly of polyoxometalates into discrete supramolecular triangles.

Pd(II)-directed self-assembly of a 3-pyridyl grafted Lindqvist hexavanadate led to the formation of a unique trimeric species, as confirmed by a variety of techniques, including pulsed-field gradient NMR spectroscopy and high-resolution ESI mass spectrometry.

Separation of chitosan oligomers by immobilized metal affinity chromatography.

A novel approach for chitosan oligosaccharide (COS) separation by immobilized metal affinity chromatography (IMAC) based on the differences in the interactions of chelated copper (II) ions with various COS (dimers, trimers, tetramers) is described. Polyhydroxylic chromatographic supports (agarose CL-6B and silica) were functionalized with various chelating functions such as iminodiacetate (IDA), carboxymethyl-aspartate (CM-Asp) and tris(carboxymethyl)ethylenediamine (TED). The COS retention capacities of the columns were between 2 and 6 mg/cm(3), depending on the chelating group. The COS were separated and/or enriched up to 95% for dimer and trimer and 90% for the tetramer, with yields of 60-95%.

Improvement in peptide detection for proteomics analyses using NanoLC-MS and high-field asymmetry waveform ion mobility mass spectrometry.

Sensitive and selective detection of multiply charged peptide ions from complex tryptic digests was achieved using high-field asymmetric waveform ion mobility spectrometry (FAIMS) combined with nanoscale liquid chromatography-mass spectrometry (nanoLC-FAIMS-MS). The combination of FAIMS provided a marked advantage over conventional nanoLC-MS experiments by reducing the extent of chemical noise associated with singly charged ions and enhancing the overall population of detectable tryptic peptides. Such advantages were evidenced by a 6-12-fold improvement in signal-to-noise ratio measurements for a wide range of multiply charged peptide ions. An increase of 20% in the number of detected peptides compared to conventional nanoelectrospray was achieved by transmitting ions of different mobilities at high electric field vs low field while simultaneously recording each ion population in separate mass spectrometry acquisition channels. This method provided excellent reproducibility across replicate nanoLC-FAIMS-MS runs with more than 90% of all detected peptide ions showing less than 30% variation in intensity. The application of this technique in the context of proteomics research is demonstrated for the identification of trace-level proteins showing differential expression in U937 monocyte cell extracts following incubation with phorbol ester.