Expression of stress proteins in cultured human cells as a sensitive indicator of metal toxicity

Human cell lines cultured under standardized conditions are found to react after a wide variety of aggressive but sub-lethal treatments by expressing stress proteins, mainly of the HSP68, HSP70 and HSP90 families. The stress reaction is a repair mechanism which rapidly takes place after minute damages caused to cell structures. It was therefore proposed to develop a sensitive biomarker to monitor environmental pollution, especially related to metals, based on the evaluation of stress protein production. This was achieved by computer-assisted densitometric analysis of autoradiographies of electrophoretically separated (35)S-labelled proteins. The results indicate that our biological models consisting in HT29 and HepG2 cell-lines react to low concentrations of cadmium or nickel by a clear-cut increase of stress proteins expression. In most cases, this effect is much more significant and much more rapid to observe than changes in growth curves. It may constitute a reliable index of cell susceptibility to environmental aggressions.     

Surface selectivities in wet chemically modified PVC films. Influence of reaction conditions

Wet chemical modification reactions of PVC films in solvent/nonsolvent mixtures were performed. Three thiol compounds of different size and reactivity were used varying the solvent quality, temperature, and reaction times. The evolution of the concentration gradients within the films was studied using confocal Raman spectroscopy and attenuated total reflectance Fourier transform infrared spectroscopy. Surface selectivities were calculated and discussed in terms of the different relative reaction rate constants.     

Parham-type cycliacylation with Weinreb amides. Application to the synthesis of fused indolizinone systems

[reaction: see text] Weinreb amides behave as efficient internal electrophiles in Parham-type cycliacylation reactions. Thus, aryl- and heteroaryllithiums generated by lithium-halogen exchange undergo intramolecular cyclization to give fused indolizinone systems as pyrrolo[1,2-b]isoquinolines, thieno[2,3-f]indolizinones, and pyrrolo[1,2-b]acridinones in high yields.     

Langmuir monolayer characteristics of a perfluoroaryl surfactant: 10-Perfluorobenzyl-decan-1-ol (PBD)

A surfactant containing the perfluorobenzyl moiety attached at the 10 position of decanol (10-perfluorobenzyldecan-1-ol, PBD) was synthesized and employed for Langmuir monolayer characterization, using surface pressure (π) and electric surface potential (ΔV)-mean molecular area (A) isotherms. Both static and dynamic stability experiments demonstrate that the monolayers formed by PBD are of satisfactory stability. Characteristic dendritic structures were observed with Brewster Angle Microscope (BAM) upon the whole compression up to the vicinity of collapse, where 3D crystallites appeared. The monolayer thickness is found to be comparable to the PBD molecule length. It occurs that ΔV has negative value even at large molecular areas, and decreases gradually along the compression, reaching a minimum of ca. −500 mV. Using the Helmholtz model, the apparent dipole moment was calculated upon film compression. The measurements were complemented with semi-empirical calculations involving molecular geometry optimization and dipole moment estimation.     

DFT study of the EPR spectral pattern of propagating methacrylic radicals

The EPR spectral pattern observed in the bulk polymerization of methacrylic monomers was theoretically investigated by DFT methodology. The conformational analysis of the propagating radical by the rotation around the C–C_β bond, was performed using the B3LYP/6-31G^* computational scheme. To obtain accurate values of the isotropic hyperfine coupling constants (hfccs) a higher level protocol, B3LYP/TZVP//B3LYP/6-31G^*, was applied. The experimental 13-line spectrum registered at the first stage of the polymerization was assumed to correspond to a free rotating radical in a fluid medium and it was simulated just considering the most stable conformation. The 9-line spectrum registered at high conversions was interpreted in terms of highly hindered rotational conformers frozen in the very viscous medium. This spectrum was well reproduced by a model which considers the sum of the individual spectra of the conformations spread around the most probable. Each of these contributing spectra was obtained on the basis of the computed hfccs for the considered conformations and weighted by his relative Boltzmann population according to the DFT analysis. Besides, the calculated hfccs showed an excellent agreement with those predicted by the Heller–McConnell relationship, which confirms the coherence of the DFT methodology for this kind of calculations.     

Isolation of a stable 1-iridabicyclo[3.2.0]hepta-1,3,6-triene and its reversible transformation into an iridacycloheptatriene

Reaction of the iridacyclopentadiene complex 2 with 2-butyne yields a mixture in equilibrium of the iridacycloheptatriene 3 and a novel 1-iridabicyclo[3.2.0]hepta-1,3,6-triene, 4.     

Inclusion Complexation of Carbaryl and β-Cyclodextrin in Solution and in the Solid State

This study was carried out with the aim ofinvestigating the interactions between-cyclodextrin and carbaryl, a carbamatepesticide, and their effect on some physico-chemicalproperties of carbaryl, such as aqueous solubility andlipophilicity. The interactions between carbaryl and-cyclodextrin were thoroughly investigated bothin solution and in the solid state. The effect of-cyclodextrin on the aqueous solubility ofcarbaryl was evaluated by the phase solubility method.The amount of carbaryl dissolved increased linearlywith the addition of -cyclodextrin according toan A_L type plot and without precipitation of thecomplex. The apparent stability constant of thecomplex was 289 ± 21 M^-1, assuming a 1 : 1stoichiometry; this value was confirmed by a methodbased on circular dichroism measurements.Equimolar carbaryl/-cyclodextrin solid systemswere prepared by physical-mixing and freeze-drying,and fully characterised by Differential ScanningCalorimetry, X-ray powder diffractometry and FourierTransform Infra-Red analysis. The results of the solidstate study demonstrated that the freeze-drying methodyields a system with a high degree of amorphisationand yields an inclusion complex.The dissolution profile of the pesticide was affectedby the physico-chemical properties of each solidsystem, the freeze-dried form dissolving more rapidly. However, the physical association of-cyclodextrin and carbaryl enhanced the aqueoussolubility of the insecticide as well.     

Pyridazines. Part 31: synthesis and antiplatelet activity of 4,5-disubstituted-6-phenyl-3(2H)-pyridazinones

This paper describes the synthesis and the antiplatelet activity of a series of 4,5-disubstituted-6-phenyl-3(2H)-pyridazinones. Some of these compounds show a dose-dependent activity and were found to be more active than their 5-substituted analogues.     

Intercalation Compounds between Ethyl 2-oxocyclopentanecarboxylate and Saponite

The retention of ethyl 2-oxocyclopentanecarboxylate by a saponite has been studied. Intercalation compounds were prepared by two different methods: 1) in repose at room temperature and 2) heating at 60 °C under reflux. Contact times between 2 and 12 days were considered for each method. The intercalation compounds obtained were characterized by X-ray diffraction, infrared spectroscopy, chemical analyses and thermal analyses. This characterization indicates that the organic compound is retained both in the interlayer region and at the edge of the clay particles. The amount retained outside of the interlayer space is eliminated by careful washing with benzene and cyclohexane. The results obtained when using acid-activated saponite -obtained by treatment of the clay with dilute HCl solutions- in the intercalation experiments were similar to those obtained when using non-activated saponite.