A multi-institutional study confirms the presence and expression of simian virus 40 in human malignant mesotheliomas

Exposure to the carcinogen asbestos is a major factor in the development of malignant mesothelioma. However, not all mesotheliomas are associated with asbestos exposure, and only a small minority of people exposed to asbestos develop mesothelioma. Therefore, the identification of the cofactors that render certain individuals more susceptible to asbestos or that cause mesothelioma in people not exposed to asbestos has been a major priority of the International Mesothelioma Interest Group. The possible association of SV40 with mesothelioma was recently discussed in a special session at the Fourth International Mesothelioma Interest Group Conference, and it was decided to conduct a multi-institutional study to independently verify the presence of this tumor virus in mesotheliomas. We report the results of this investigation: (a) DNA and protein analyses revealed SV40 sequences and SV40 large T antigen expression in 10 of 12 mesotheliomas tested (83%); and (b) electron microscopy demonstrated variable amounts of asbestos fibers in 5 (71%) of 7 corresponding lung tissues available for analysis. Our results demonstrate that SV40 DNA is frequently present and expressed in mesotheliomas in the United States. Because our data demonstrate that some patients test positive for both SV40 and asbestos, the possibility that these two carcinogens interact should be investigated in future studies.     

Nitro derivatives of PEEK‐WC

Nitrated poly(oxa‐p‐phenylene‐3,3‐phthalido‐p‐phenylene‐oxa‐p‐phenylene‐ oxy‐phenylene) (PEEK‐WC) with various average degrees of substitution was obtained by reaction with several nitrating agents. By working under controlled reaction conditions, little degradation of the parent polymer is observed. The nitro derivatives of PEEK‐WC show a high thermal stability, and are able to form membranes by means of phase inversion technique. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1037–1045, 2001     

Interaction of the σ2 Receptor Ligand PB28 with the Human Nucleosome: Computational and Experimental Probes of Interaction with the H2A/H2B Dimer

Sigma‐2 (σ₂) binding sites are an emerging target for anti‐neoplastic agents due to the strong apoptotic effect exhibited by σ₂ agonists in vitro and the overexpression of these sites in tumor cells. Nonetheless, no σ₂ receptor protein has been identified. Affinity chromatography using the high‐affinity σ₂ ligand PB28 and human SK‐N‐SH neuroblastoma cells was previously utilized to identify σ₂ ligand binding proteins, specifically histones H1, H2A, H2B, and H3.3a. To rationalize this finding, homology modeling and automated docking studies were employed to probe intermolecular interactions between PB28 and human nucleosomal proteins. These studies predicted interaction of PB28 with the H2A/H2B dimer at a series of sites previously found to be implicated in chromatin compaction and nucleosomal assembly. To experimentally verify this prediction, a competitive binding assay was performed on the reconstituted H2A/H2B dimer using [³H]PB28 as radioligand, and an IC₅₀ value of 0.50 nM was determined for PB28 binding. In addition, [³H]PB28 was found to accumulate with up to a fivefold excess in nuclear fractions over cytosolic fractions of SK‐N‐SH and MCF7 cells, indicating that PB28 is capable of entering the nucleus to interact with histone proteins. In conjunction with computational results, these data suggest that PB28 may exert its cytotoxic effect through direct interaction with nuclear material.     

Spontaneous copolymerization of N-(2-hydroxyethyl)ethyleneimine with isatoic anhydride

The polymerization of isatoic anhydride (electrophilic monomer) with N-(2-hydroxyethyl)ethyleneimine (nucleophilic monomer) was studied in the absence of added initiator at different feed monomer concentrations, temperature, and time of copolymerization. The copolymers were characterized by FT-IR, ¹H-NMR and ¹³C-NMR spectroscopy, and TGA. Based on spectroscopic data and copolymer composition, a copolymer structure was suggested. Received: 25 April 1997/Revised: 11 August 1997/Accepted: 14 August 1997     

Characterization of the molecular heterogeneity of copolymers obtained via zwitterion by capillary zone electrophoresis

Summary Using capillary zone electrophoresis has made characterizations of different copolymers obtained via zwitterionic polymerization. Results demonstrate that this technique is able to put into evidence the molecular heterogeneity of the different copolymers. Analyses were performed in less than 10 minutes using a borate buffer. To our knowledge this the first time that free-zone capillary electrophoresis has been applied to the characterization of copolymers systems below the oligomer range obtained via zwitterion polymerization. Received: 27 April 2001/Revised version: 24 November 2001/ Accepted: 9 January 2002     

A simple PCR-based macroarray system for detection of multiple gene markers in the identification of priority enterohemorrhagic Escherichia coli

Enterohemorrhagic Escherichia coli (EHEC) strains bearing the O antigenic determinants O157, O26, O111, O103, and O145 have a high rate of association with foodborne illness worldwide. To expand Canadian food inspection capability, a cloth-based hybridization array system (CHAS) was developed for the identification and characterization of priority EHEC. This method targets key virulence genes (eae, hlyA, vt1, and vt2) plus the rfbE gene specifying the O157 antigenic determinant, and the wzx genes specifying the O26, O111, O103, and O145 determinants. Multiplex PCR products incorporating a digoxigenin label were detected by hybridization with an array of specific oligonucleotide probes immobilized on a polyester cloth support, with subsequent immunoenzymatic assay of the captured amplicons. This method identified the relevant markers in 85 different strains bearing various combinations of the target genes (virulence and priority O-antigen markers). None of the target genes was detected in 26 different strains of other E. coli and non-E. coli bacteria. The CHAS demonstrated 100% inclusivity and 100% exclusivity characteristics, with respect to detection of the various markers among different bacterial strains. The CHAS demonstrated 100% inclusivity and 100% exclusivity characteristics, with respect to detection of the markers among various target and nontarget bacteria. The entire procedure could be completed in less than 5 h, and is useful for the identification of priority EHEC colonies isolated from foods by using enrichment culture techniques.     

Alumina Grown during Deposition of Thermal Barrier Coatings on NiCrAlY

The microstructure of Al₂O₃ formed by oxidation of a model NiCrAlY alloy during electron-beam physical vapor deposition of ZrO₂–7.6 mol% YO_1.5 is examined and compared with that formed on the bare substrate. The growth rate, morphology, and chemical composition of the oxide vary among the different constituents of the alloy surface and are further influenced by the O₂ partial pressure and the physical presence of the thermal barrier coating (TBC) layer. These differences, however, are largely limited to the outer oxide layer. The interplay between the TBC and the growing oxide leads to the formation of a fine-grain Al₂O₃–ZrO₂"mixed zone" within the thermally grown oxide. A mechanism is outlined to explain this behavior, based on the dissolution of ZrO₂ in a transient Al₂O₃ structure growing by outward diffusion of Al, and its subsequent reprecipitation when the metastable phase transforms to the stable α-Al₂O₃ form.     

Natural compounds to preserve fresh fish burgers

Natural antimicrobial compounds to control the quality decay of a fresh fish burger were studied. In particular, thymol, lemon extract and grape fruit seed extract (GFSE), at 20, 40 and 80 ppm, have been tested against the main spoilage microorganisms inoculated in fish burgers stored at 5 °C. The evolution of mesophilic and psychrotrophic bacteria was also monitored. The sensorial quality decay was determined by means of a panel test, which assessed odour, colour, texture, drip loss and general appearance during the storage period. Results show that all the active substances efficiently slowed down the growth of the spoilage microorganisms. In particular, GFSE was the most efficient against Photobacterium phosphoreum , Shewanella putrefaciens and mesophilic bacteria, whereas thymol was the most efficient against both psychrotrophic bacteria and Pseudomonas fluorescens . Microbial growth was the factor limiting fresh fish burger acceptability.