An old workhorse for new applications: Fe(dpm)3 as a precursor for low-temperature PECVD of iron(III) oxide.

An iron(III) ß-diketonate complex, Fe(dpm)3 (Hdpm = 2,2,6,6-tetramethyl-3,5-heptanedione), has been investigated as a potential precursor for plasma enhanced chemical vapor deposition (PECVD) of iron(III) oxide nanomaterials. Thanks to the combined experimental-theoretical approach, spectroscopic properties, spin state, thermal behavior and fragmentation pathways of Fe(dpm)3 have been carefully analysed, obtaining an excellent agreement between simulation and experiment. Preliminary PECVD tests evidenced the possibility of obtaining pure and homogeneous Fe2O3 deposits with controlled nano-organization at temperatures as low as 100 °C, even on flexible plastic substrates. The present results open up intriguing perspectives for the exploitation of Fe(dpm)3 as an efficient molecular source for the preparation of nanostructured iron(III) oxides to be used in energetics and gas sensing applications.

High-density lipoprotein oxidation in type 2 diabetic patients and young patients with premature myocardial infarction.

BACKGROUND AND AIMS: ApoA-I can undergo oxidative changes that reduce anti-atherogenic role of HDL. The aim of this study was to seek any significant differences in methionine sulfoxide (MetO) content in the ApoA-I of HDL isolated from young patients with coronary heart disease (CHD), type 2 diabetics and healthy subjects. METHODS AND RESULTS: We evaluated the lipid profile of 21 type 2 diabetic patients, 23 young patients with premature MI and 21 healthy volunteers; we determined in all patients the MetO content of ApoA-I in by MALDI/TOF/TOF technique. The typical MALDI spectra of the tryptic digest obtained from HDL plasma fractions all patients showed a relative abundance of peptides containing Met(112)O in ApoA-I in type 2 diabetic and CHD patients. This relative abundance is given as percentages of oxidized ApoA-I (OxApoA-I). OxApoA-I showed no significant correlations with lipoproteins in all patients studied, while a strong correlation emerged between the duration of diabetic disease and OxApoA-I levels in type 2 diabetic patients. CONCLUSIONS: The most remarkable finding of our study lies in the evidence it produced of an increased HDL oxidation in patients highly susceptible to CHD. Levels of MetO residues in plasma ApoA-I, measured using an accurate, specific method, should be investigated and considered in prospective future studies to assess their role in CHD.

A comparison between MALDI-MS and CE-MS data for biomarker assessment in chronic kidney diseases.

Non-invasive detection of diseases, based on urinary proteomics, is becoming an increasingly important area of research, especially in the area of chronic kidney disease (CKD). Different platforms have been used in independent studies, mostly capillary-electrophoresis coupled ESI-MS (CE-MS), liquid chromatography coupled mass spectrometry, and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). We have compared the performance of CE-MS with MALDI-MS in detecting CKD, based on a cohort of 137 urine samples (62 cases and 75 controls). Data cross-talk between the two platforms was established for the comparison of detected biomarkers. The results demonstrate superior performance of the CE-MS approach in terms of peptide resolution and obtained disease prediction accuracy rates. However, the data also demonstrate the ability of the MALDI-MS approach to separate CKD patients from controls, at slightly reduced accuracy, but expected reduced cost and time. As a consequence, a practical approach can be foreseen where MALDI-MS is employed as an inexpensive, fast, and robust screening tool to detect probable CKD. In a second step, high resolution CE-MS could be used in those patients only that scored negative for CKD in the MALDI-MS analysis, reducing costs and time of such a program.

Solution behaviour and biological activity of bisamidine complexes of platinum(II).

A series of platinum(II) amidine complexes were previously prepared with the aim of obtaining a new class of platinum-based antitumour drugs. This series includes compounds of the type cis--[PtCl2{Z-HN=C(NHMe)Me}2] and trans-[PtCl2{Z-HN=C(NHMe)Me}2] (1, 2), cis-[PtCl2{E-HN=C(NMe2)Me}2] and trans-[PtCl2{E-HN=C(NMe2)Me}2] (3, 4), cis-[PtCl2{Z-HN=C(NHMe)Ph}2] and trans-[PtCl2{Z-HN=C(NHMe)Ph}2] (5, 6), and cis-[PtCl2{HN=C(NMe2)Ph}2] and trans-[PtCl2{HN=C(NMe2)Ph}2] (7, 8). The reactions with dimethyl sulfoxide were studied for complexes 5-8; the formation of cationic species containing coordinated dimethyl sulfoxide was demonstrated by NMR experiments and electrospray ionization mass spectrometry. In this work, the amidine platinum(II) complexes were tested for their in vitro cytotoxicity on a panel of various human cancer cell lines. The results indicate that the benzamidine complex 8 was the most effective derivative also circumventing acquired cisplatin resistance as demonstrated by chemosensitivity tests performed on cisplatin-sensitive and cisplatin-resistant cell lines. The studies concerning the cellular DNA damage on both parental chemosensitive and resistant sublines suggest for the new trans-amidine complex a different mechanism of action compared with that exhibited by cisplatin.

Surfactant self-assembling in gas phase: electrospray ionization- and matrix-assisted laser desorption/ionization-mass spectrometry of singly charged AOT clusters.

The self-assembling of sodium bis (2-ethylhexyl) sulfosuccinate (AOT) in gas phase has been investigated by electrospray ionization- and matrix-assisted laser desorption/ionization mass spectrometry. Large surfactant clusters with an aggregation number close to that found in apolar media have been observed either as positive or negative ions. Moreover, the marked predominance of singly charged species as well as preliminary theoretical calculations strongly suggest an aggregate structure characterized by an internal hydrophilic core hosting the extra charge surrounded by an apolar shell constituted by the surfactant alkyl chains. This structure is similar to that of the more familiar reversed micelles formed when an appropriate surfactant is solubilized in apolar solvents. Finally, similar trends are observed independently either on the ionization technique or the polarity of the solvent used. This, together with the large dependence of the aggregation number on the flow rates, strongly indicates that self-assembling of the surfactant molecules occurs during the evaporation step.

Evaluation of glyoxal and methylglyoxal levels in uremic patients under peritoneal dialysis.

Advanced glycation end products (AGEs) accumulate in serum and tissues of patients with chronic renal failure, even in the absence of diabetes, and a different clearance of these species has been observed by hemodialysis and peritoneal dialysis (CAPD). Furthermore, it has been shown that not only AGE but also 1,2-dicarbonyl compounds are formed during heat sterilization of glucose-based peritoneal dialysis fluids. Therefore, we investigated the level of some AGEs (pentosidine and free pentosidine) and dicarbonyl compounds (glyoxal and methylglyoxal) in end-stage renal disease patients subjected to peritoneal dialysis. Samples (20 from healthy subjects, 16 from uremic patients before and after 12 h of peritoneal dialysis) were analyzed, and the plasma and dialysate levels of glyoxal, methylglyoxal, pentosidine, and free pentosidine were determined. In plasma of uremic patients, mean values of pentosidine showed a small decrease after dialysis and were always higher than those of healthy control subjects. An analogous trend was observed for free pentosidine. In the case of peritoneal dialysate, no pentosidine and free pentosidine were found at time zero, whereas both compounds were detected after 12 h of dialysis. Glyoxal and methylglyoxal mean levels showed a decrease in plasma after dialysis even if their values were always higher than those of healthy control subjects. Surprisingly, an analogous trend was observed also in dialysate. These results might indicate that glyoxal and methylglyoxal already present in the dialysis fluid react with the peritoneal matrix proteins, accounting for the gradual loss of peritoneal membrane function that is often observed in patients subjected to CAPD for a long time.

Advanced glycation end products/peptides: an in vivo investigation.

Advanced glycation end products/peptides (AGE/peptides) originate by in vivo enzymatic digestion of nonenzymatically glycated proteins, which are produced by reaction of glucose with primary amino groups present in the protein chain following the Maillard pattern. AGE/peptides are highly reactive species and can interact with tissue and circulating proteins, leading to tissue modification and impaired protein functionality. Serum levels of AGE/peptides are reported to be particularly high in diabetes (in terms of higher production) or in end-stage renal disease (in terms of accumulation). For these reasons, their structural identification is of high interest, giving information on their relationship with the pathological state and allowing the design of possible therapeutic interventions. We report here some preliminary results obtained by liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) and matrix-assisted laser desorption ionization MS (MALDI-MS) investigations carried out on the low-molecular-weight serum peptide fraction from 10 healthy subjects, 10 patients with poorly controlled diabetes, and 10 patients with end-stage nephropathy.

A matrix-assisted laser desorption/ionization mass spectrometry study of the non-enzymatic glycation products of human globins in diabetes.

The molecular species present in globins from healthy and diabetic subjects with and without chronic complications have been analyzed by matrix-assisted laser desorption/ionization mass spectrometry. The technique demonstrated the presence of glycated and glyco-oxidated species of both alpha- and beta-globins. Their abundances show a good linear relationship with respect to HbA1c values and with the mean daily plasma glucose levels over the 6 weeks preceding the investigation. Interestingly, slightly different behaviour is observed in the data from patients with and without chronic complications; the plots of HbA1c vs. the abundance of glycated and glyco-oxidated species show different slopes and different intercepts with the y-axis. To investigate this aspect the mean abundances of glyco-oxidated species from healthy subjects and from diabetic patients with and without complications were calculated. Higher values were found for the two last sets of samples, but no significant difference was found between them. These data could indicate different individual proclivities to oxidation and/or different oxidation kinetics related to behavioural and environmental factors.

The complexity of non-enzymatic glycation product sets of human globins.

AIMS/HYPOTHESIS: Recently an individual variability in the relationships between mean blood glucose levels and HbA1c has been observed among diabetic patients. The aim of this study was to provide an accurate description and evaluation of glycated and glyco-oxidated globins from diabetic subjects and their relationship with HbA1c and plasma glucose values. METHODS: We studied 20 type 2 diabetic and 10 healthy subjects. Plasma samples were analysed by matrix-assisted laser desorption ionisation mass spectrometry. RESULTS: The presence of glycated and glyco-oxidated species of both alpha and beta globin was demonstrated. Values for these showed a good linear relationship with HbA1c values and the mean daily plasma glucose values for the 6 weeks preceding the investigation. Trends differed according to whether patients had chronic complications or not, differences being seen in the slopes of the plots relating HbA1c to the abundance of glycated and glyco-oxidated species. CONCLUSIONS/INTERPRETATION: The data obtained are consistent with the concept that individuals have a different individual proclivity for oxidation and/or that different oxidation kinetics are related to behavioural and environmental factors. Our data are thus relevant to the analysis of phenotype differences in diabetic patients.

Characterization studies and cytotoxicity assays of Pt(II) and Pd(II) dithiocarbamate complexes by means of FT-IR, NMR spectroscopy and mass spectrometry.

The precursors [M(ESDTM)Cl(2)] (M=Pt(II), Pd(II); ESDTM=EtO(2)CCH(2)(CH(3))NCS(2)Me, S-methyl(ethylsarcosinedithiocarbamate)) were synthesized as previously reported [J. Inorg. Biochem. 83 (2001) 31] and used to obtain [M(ESDT)Cl](n) (ESDT=ethylsarcosinedithiocarbamate anion) species. The complexes formed through reaction between [M(ESDT)Cl](n) and the two chiral amino-alcohols synephryne (Syn) and norphenylephrine (Nor) have been synthesized, with the ultimate goal of preparing mixed dithiocarbamate/amino metal complexes of the type [M(ESDT)(Am)Cl] (Am=Syn, Nor). These compounds have been isolated, purified and characterized by means of FT-IR, mono- and bidimensional NMR spectroscopy and mass spectrometry ESI/MS (electronspray mass spectra). The experimental data suggest that in all cases coordination of the dithiocarbamate ligand (ESDT) takes a place through the two sulfur atoms, the -NCSS moiety acting as a symmetrical bidentate chelating group, in a square-planar geometry around the M(II) ion, while the other two coordination positions are occupied by the chlorine atom and the amino-alcohol ligand, respectively. In particular, synephrine and norphenylephrine appear to be bound to the metal atom through the amino nitrogen atom by means of a dative bond. Finally, the biological activity of the new complexes has been studied by MTT (tetrazolio salt reduction) test and by detecting the inhibition of DNA synthesis and of clonal growth in various cancer cell lines. All Pd(II) derivatives showed a noticeable activity very close to that of cisplatin, used as reference drug. Moreover, they showed significantly reduced cross-resistance to cisplatin in a pair of cell lines (2008/C13*) with known acquired cisplatin resistance mechanisms.

Non-enzymatic glycation of IgG: an in vivo study.

The IgG glycation level of 30 healthy subjects and 60 type 2 diabetic patients with different degrees of metabolic control was evaluated by matrix-assisted laser desorption ionization mass spectrometry, a technique allowing the determination of mass increase of the IgG molecule. When applied to the digested mixture obtained by the action of papain on the plasma protein fraction, the same method established the mass increase of Fab and Fc fragments of IgG; for the former, a higher mass increase was found, possibly explained by its high reactivity to glucose. Experimental results were confirmed by molecular modeling calculations. Results suggest that the immunodeficiency observed in diabetic patients may be due to the inhibition of molecular recognition between antibody and antigen as a result of a change in functionality of the modified Fab fragment of IgG.

Serum protein profiles of patients with pancreatic cancer and chronic pancreatitis: searching for a diagnostic protein pattern.

In this study, 13 sera from patients with pancreatic cancer, 9 from chronic pancreatitis and 10 from healthy subjects were analyzed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The MALDI mass spectra revealed the presence of several low molecular weight peptides, among which some were detected only in the sera from both pathological conditions. On the other hand many peptides were observed only in control sera, and were absent in the sera from the two diseases. Therefore, MALDI analysis of the low molecular weight fraction (<10 000 Da) of sera from patients with pancreatic diseases enabled us to identify the presence of some disease-related signals and also some signals characteristic of normal subjects.

Isolation and characterization of photosystem II subcomplexes from cyanobacteria lacking photosystem I.

A photosystem II (PSII) core complex lacking the internal antenna CP43 protein was isolated from the photosystem II of Synechocystis PCC6803, which lacks photosystem I (PSI). CP47-RC and reaction centre (RCII) complexes were also obtained in a single procedure by direct solubilization of whole thylakoid membranes. The CP47-RC subcore complex was characterized by SDS/PAGE, immunoblotting, MALDI MS, visible and fluorescence spectroscopy, and absorption detected magnetic resonance. The purity and functionality of RCII was also assayed. These preparations may be useful for mutational analysis of PSII RC and CP47-RC in studying primary reactions of oxygenic photosynthesis.