N1-substituted benzamidines: synthesis, antiproteinase activity and inhibition of tumor cell growth.

We have synthesized N1-substituted benzamidines and poly-benzamidines with the aim to produce antitumor drugs retaining differential biological properties with respect to unsubstituted compounds. Antiproliferative activity on in vitro cultured human leukemic cells was exhibited by N1-substituted poly-benzamidines, while N1-substituted benzamidines were found to retain very low antitumor effects. Furthermore, our results suggest that N1-substituted benzamidines and some of poly-benzamidines exhibit low activity on trypsin and kallikrein. Taken together these data indicate that some N1-substituted poly-benzamidines could be of interest for experimental antitumor therapy, since are likely to retain low side effects due to alteration of proteinase activity.

Expression of 8-OHdG in Zosterisessor ophiocephalus from the Venetian lagoon, Italy.

The aim of the present work was to evaluate the expression of 8-OHdG (8-hydroxydeoxyguanosine) in the benthic fish Zosterisessor ophiocephalus collected in two differently polluted sites of the Venetian lagoon (Porto Marghera and Caroman). We compared our data on 8-OHdG with those of CYP1A (Cytochrome P450, family 1, subfamily A, polypeptide 1), which is a well known biomarker for detoxification of contaminants. Immunohistochemistry with an antibody to 8-OHdG showed immunopositivity in nuclei of hepatocytes as well as in melanomacrophage centres of spleen and kidney, whereas an anti-CYP1A antibody exhibited positive immunostaining in the liver, kidney and ovary. The liver of males showed higher expression of both proteins than females. In animals from Porto Marghera site, the enzymatic assay for 8-OHdG exhibited higher levels in liver of males than in females. Western Blot analysis using the antibody anti-CYP1A recognized the presence of a band of about 60 kDa in the liver of males and females. Males exhibited a strong band, whereas in females the band showed a lower intensity. By using Real-Time PCR, the mRNA expression of CYP1A did not show any differences between males and females from each site, but it was at borderline significance level. Comparing the two sites, mRNA expression of CYP1A was significantly higher in the liver of both males and females from Porto Marghera than that of Caroman. The present data suggest that pollutants are bio-available as demonstrated by our biomarker analyses and may have a harmful effect on aquatic organisms such as Z. ophiocephalus. We report that the highest levels of hepatic 8-OHdG and CYP1A expression were detected in males, showing clear gender specificity.

A packaging contaminant: isopropylthioxanthone (ITX) in dairy products.

A fast, simple and very selective liquid chromatography-mass spectrometry (LC-MS) method for the detection of isopropylthioxanthone (ITX) in dairy products has been developed and validated. After addition of an ITX-d(3) as internal standard and a simple extraction from the sample with acetonitrile, the extract was centrifuged and directly injected into the LC-MS system. Chromatographic separation was achieved by means of a Gemini C18 column (100 mm x 2.0 mm i.d. 5 microm) using a gradient of aqueous 20 mM ammonium formiate at pH 4.5 and methanol as the mobile phase, at a flow rate of 0.25 mL min(-1). The method was validated according to the guidelines laid down by the Commission Decision 2002/657/EC using the parent ion [M+H](+) (m/z 255) as quantification ion, and the fragment ion (m/z 213) obtained by in-source collision-induced dissociation (IS-CID) as confirmation ion. Absolute and relative recoveries rates were verified at 5, 10, 15 microg kg(-1) in yoghurt samples and at 5 microg kg(-1) in milk and pudding: mean absolute recoveries were 77% in yoghurt, 50% in pudding and 67% in milk; relative recoveries (after internal standard correction) were always >97% in each matrix. The detection limit (CCalpha) and the detection capability (CCbeta) of method were 6.2 and 7.2 microg kg(-1), respectively.

Simultaneous determination of lincomycin and five macrolide antibiotic residues in honey by liquid chromatography coupled to electrospray ionization mass spectrometry (LC-MS/MS).

A sensitive and specific method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), for the simultaneous determination of lincomycin and five macrolide antibiotics in honey, was developed and validated. The analytes were extracted with Tris buffer 0.1 M, pH 10.5, and cleaned-up by a single solid-phase extraction step on OASIS HLB column. The chromatographic separation of analytes was performed on a Synergi Hydro-RP reversed-phase column using a gradient programme of aqueous 0.01 M ammonium acetate, pH 3.5, and acetonitrile as the mobile phase, at a flow rate 0.25 ml min-1. The detection of analytes was achieved by positive ionization electrospray in multiple reaction-monitoring mode. Two characteristic transitions were monitored for each substance. The following analytical parameters were validated according to the guidelines laid down by European Commission Decision 2002/657/EC (European Commission 2002): linearity, specificity, decision limit (CCalpha), detection capability (CCbeta), repeatability, within-laboratory reproducibility, recovery and ruggedness.