Matrix-assisted laser desorption/ionization mass spectrometry imaging sample preparation using wet-interface matrix deposition for lipid analysis.

Rationale: Sample preparation is one of the most crucial steps for matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). Scientists beginning their study with this technique may be overwhelmed by the variety of matrices, solvents, and concentrations; the methods of their applications; and the lack of widely available knowledge of the effect of these parameters on the results. Here we present in depth the aspects of matrix deposition, which will be helpful for the scientific community.

The Study of Derivatization Prior MALDI MSI Analysis-Charge Tagging Based on the Cholesterol and Betaine Aldehyde.

Mass spectrometry imaging is a powerful tool for analyzing the different kinds of molecules in tissue sections, but some substances cannot be measured easily, due to their physicochemical properties. In such cases, chemical derivatization could be applied to introduce the charge into the molecule and facilitate its detection. Here, we study cholesterol derivatization with betaine aldehyde from tissue slices and evaluate how different sample preparation methods influence the signal from the derivatization product.

New 5-HT, 5HT and 5HT receptor ligands containing a picolinic nucleus: Synthesis, in vitro and in vivo pharmacological evaluation.

Picolinamide derivatives, linked to an arylpiperazine moiety, were prepared and their affinity to 5-HT, 5-HT and 5-HT receptors was evaluated. The combination of structural elements (heterocyclic nucleus, alkyl chain and 4-substituted piperazine), known to play critical roles in affinity for serotoninergic receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. In binding studies, several molecules showed high affinity in nanomolar and subnanomolar range at 5-HT, 5-HT and 5-HT receptors and moderate or no affinity for other relevant receptors (D, D, α and α).

DESI analysis of mammalian cell cultures--preparation and method optimisation.

Desorption electrospray ion source (DESI) is widely used as an MS imaging technique. It is a rapid and convenient method of surface analysis, but to date, there are methodological obstacles to its application to the analysis of cell culture. This study reported optimised conditions for the analysis of cell culture samples.

Desorption electrospray ionisation (DESI) for beginners--how to adjust settings for tissue imaging.

Rationale: Desorption electrospray ionisation (DESI) is the ambient technique used for surface imaging. Despite its simplicity, the proper use of this technique is not easy, and usually leads to discouragement, especially in the case of biological sample measurements. Here, we present some tips and tricks which may be helpful during a complex process of ion source optimisation to achieve the desired results.

Constant activity of glutamine synthetase after morphine administration versus proteomic results.

Glutamine synthetase is a key enzyme which has a regulatory role in the brain glutamate pool. According to previously published proteomic analysis, it was shown that the expression level of this enzyme is affected by morphine administration. In our study, we examined the activity of glutamine synthetase in various structures of rat brain (cortex, striatum, hippocampus and spinal cord) that are biochemically and functionally involved in drug addiction and antinociception caused by morphine.