Pericentriolar material analyses in normal esophageal mucosa, Barrett's metaplasia and adenocarcinoma.

Barrett's esophagus metaplasia is a pre-cancerous condition caused by chronic esophagitis. Chromosomal instability (CIN) is common in Barrett's cells: therefore, we investigated the possible presence of centrosomal aberrations (a main cause of CIN) by centrosomal protein immunostaining in paraffined esophageal samples of patients who developed a Barrett's adenocarcinoma. In most (55%) patients, alterations of the pericentriolar material (PCM) signals were evident and consistently marked the transition between normal epithelium to metaplasia.

Differential liquid phase proteomic analysis of the effect of selenium supplementation in LNCaP cells.

The effect of 100 nM sodium selenite supplementation was studied on LNCaP cells by a proteomic approach, on ProteomeLab PF 2D platform. Proteins were separated by liquid phase bi-dimensional chromatography and analyzed by pair-wise alignment of peaks to detect those differentially expressed. Differential expression threshold was set at a twice difference level and proteins matching this criterion were identified by MALDI-TOF and confirmed by ESI-ion trap MS/MS.

MPA: a multiple peak alignment algorithm to perform multiple comparisons of liquid-phase proteomic profiles.

Present proteomic studies increasingly address experimental strategies focused on multiple comparisons of proteomic profiles. To accomplish semiautomatic protein separations based on 2-D LC, the Beckman Coulter PF2D has been developed. Here, we present a novel general purpose tool called MPA (multiple peak alignment) able to perform multiple comparisons of proteomic profiles both in a pairwise guided fashion and in a fully automatic mode using a strategy based on dynamic programing and progressive alignment of time series.

Characterization of soluble oligomers produced by electrochemical oxidation of o-phenylenediamine by electrospray ionization sequential mass spectrometry.

Soluble species generated during the electropolymerization of o-phenylenediamine (o-PD) on platinum electrodes in aqueous buffers at different pH values were investigated by electrospray ionization ion trap sequential mass spectrometry (ESI-ITMS(n)). The main protonated molecules (MH(+)) detected in the full scan ESI-MS spectra of the electrolytic solutions were isolated in the ion trap and sequentially fragmented (MS(n), with n up to 5) to obtain fragmentation patterns. The latter led to hypotheses as to the molecular structures of the soluble products of o-PD electropolymerization; it appeared that all of them are actually oligomeric species in different oxidation states.