Gold as a modifier of metal nanoparticles: effect on structure and catalysis.

Bimetallic gold based catalysts have been prepared using a sol immobilisation technique. Despite a very similar metal dispersion, different structures are revealed depending on the second metal, with alloyed systems being preferred in the case of Pd, Pt and Cu, and core-shell in the case of Ru. A positive synergistic effect between the metals has been revealed only in the cases of Pd and Cu in the oxidation of benzyl alcohol. AuPd/C has been also studied in the hydrogenation of benzaldehyde where the bimetallic catalyst revealed a different selectivity compared to the monometallic counterpart.

Tetrasubstituted cyclopentadienones as suitable enantiopure ligands with axial chirality.

A series of thermally stable atropisomeric phencyclone ligands (ΔG > 35 kcal mol-1), bearing two chiral axes, has been successfully synthesized, taking into account the results of DFT calculations on model systems. The absolute configurations of the novel atropisomers have been assigned using TD-DFT simulation of ECD spectra. Atropisomeric phencyclones herein presented pave the way towards new ruthenium-based enantioselective hydrogenation catalysts.

Gold catalyzed liquid phase oxidation of alcohol: the issue of selectivity.

Commercial carbon nanotubes (CNTs) and carbon nanofibers (CNFs) modified in various ways at the surface have been used as supports for gold nanoparticles (AuNPs) in order to study their influence on the activity/selectivity of catalysts in the aqueous oxidation of alcohol. Particularly oxidative treatment was used to introduce carboxylic functionalities, whereas subsequent treatment with NH3 at different temperatures (473 K, 673 K and 873 K) produced N-containing groups leading to an enhancement of basic properties as the NH3 treatment temperature was increased. The nature of the N-containing groups changed as the temperature increased, leading to an increase in the hydrophobicity of the support surface. Similar Au particle size and similar textural properties of the supports allowed the role of chemical surface groups in both the activity and the selectivity of the reaction of glycerol oxidation to be highlighted. An increase of basic functionalities produced a consistent increase in the activity of the catalyst, which was correlated to the promoting effect of the basic support in the alcoholate formation and the subsequent C-H bond cleavage. The selectivity towards primary oxidation products (C3 compounds) was the highest for the catalysts treated with NH3 at 873 K, which presented the most hydrophobic surface. The same trend in the catalyst activity has been obtained in the aqueous benzyl alcohol base-free oxidation. As in the case of glycerol, the increasing of basicity and/or hydrophobicity increased the consecutive reactions.

Storage of chlorinated pesticides in human organs and tissues in Ferrara Province, Italy.

Residues of organochlorine compounds in human fat, liver, brain, kidney, and spleen were determined by gas chromatography. All the samples were obtained from residents of Ferrara Province, Italy, of both sexes and of ages ranging from 1 to 80 years who had no special exposure to insecticides. The following compounds were found: p,p'-DDE, o,p'-DDT, p,p'-DDT, HEOD, and heptachlor epoxide. DDT and its derivatives was found more frequently and at higher concentrations than the other compounds; the average weighted percentage ratio of DDE (as DDT) to total equivalent DDT in fat was 73.7%. The concentrations of residues in nonfatty tissues were considerably lower than in fatty tissue; in liver, and to a smaller extent in kidney, the average concentrations were higher than in other organs (brain and spleen). From comparisons of these results with those from other countries it appears that higher levels of chlorinated compounds are generally present in the Ferrara population.

[First isolation of Yersinia enterocolitica in several horticultural products intended usually to be consumed fresh]. / Primo isolamento di Yersinia enterocolitica in alcuni prodotti ortensi destinati al consumo prevalentemente allo stato fresco.

A survey has been carried out for the presence of Yersinia enterocolitica in horticultural products. 60 samples of these vegetables have been examined among the families of Compositae (lettuce, prickly lettuce, cabbage lettuce, common chicory), Ombrelliferae (curly parsley, carrot, celery, fennel) and Crociferae (garden cabbage). This is the first isolation of Y.e. from horticultural products, being recorded 7 strains from carrots (serotype 0:6,30), 1 from curly parsley (serotype 0:4,32) and 1 from celery (serotype 0: 7,8). 0:6,30 is the most frequently isolated serotype from humans after 0:3 and 0:9 (especially in Canada), and has been recovered from four cases of human infection. Its presence in carrots may strongly assume a significance of clinical importance.

Plasminogen activator inhibitor type-1 synthesis and mRNA expression in HepG2 cells are regulated by VLDL.

The effect of VLDL on plasminogen activator inhibitor type 1 biosynthesis in HepG2 cells was investigated. Exposure of HepG2 cells to VLDL (range, 10 to 100 micrograms protein per milliliter) for 16 hours resulted in an enhanced release of PAI-1 antigen and PAI activity into conditioned medium, accompanied by the accumulation of intracellular triglycerides. By using a monoclonal antibody (IgG C7) specific to the LDL receptor, we showed that the effect of VLDL is mediated by its interaction with the LDL receptor. Enhanced PAI-1 release was due to increased biosynthesis: PAI-1 mRNA was doubled, mainly because of the effect on the 2.2-kb PAI-1 mRNA rather than the 3.2-kb transcript. Addition of insulin with the VLDL further enhanced PAI-1 antigen release and PAI-1 mRNA accumulation. The effect of VLDL on steady state levels of PAI-1 mRNA was apparently not due to an increase of gene transcription but to stabilization of both PAI-1 mRNA transcripts. The enhancing effect of VLDL on PAI-1 biosynthesis in HepG2 cells may raise PAI-1 antigen levels not only in hypertriglyceridemic states but also in those conditions in which both insulin and VLDL are elevated.

Epidemiological study of long-term effects of pesticides on human health.

Two rural areas in Italy with different rates of pesticide usage were subjected to a cross-sectional investigation, based on the identification of organochlorine compounds in the environment and in human fatty tissues and on the determination of their concentration and a prospective investigation, based on the collection of data of past and present pathology and symptomatology from two stratified random groups of inhabitants of both areas.The cross-sectional investigation showed only small differences in environmental pollution and no differences in the storage of organochlorine compounds in fatty tissues in the two areas. The prospective investigation showed a higher prevalence of pathology and symptomatology in the population of the area where pesticides were used in larger quantities. Several haematochemical tests were used in an attempt to differentiate between populations at different levels of risk of toxic damage, but without success.

Effect of atherogenic lipoproteins on PAI-1 synthesis by endothelial cells.

Cultured human umbilical vein endothelial cells (EC) exposed to native and acetylated low density lipoproteins (LDL and acetyl-LDL) show an increased synthesis of PAI-1. Confluent EC monolayers were incubated for 16-18 hours in medium 199 with or without different concentrations of LDL and acetyl-LDL and PAI-1 antigen levels were measured in conditioned medium. LDL and acetyl-LDL increased the release of PAI-1 by EC in a concentration-dependent manner. The effect was specific for PAI-1 because tissue type plasminogen activator (t-PA) and expression of procoagulant activity were not affected by either lipoprotein. The observation that native and acetyl-LDL, which are known to interact with different receptors on EC, exert the same stimulatory effect on PAI-1 release rules out the possibility of an involvement of the LDL receptor in mediating this effect. Experiments carried out incubating native LDL in the presence of a monoclonal antibody against LDL receptor and using binding-defective LDL with a reduced affinity for the LDL receptor (approximately 50% with respect to normal LDL) further excluded an involvement of the classical LDL receptor in mediating the effect of the lipoproteins on PAI-1 synthesis by EC.

Effect of atherogenic lipoproteins on PAI-1 synthesis by endothelial cells.

Cultured human umbilical vein endothelial cells (EC) exposed to native and acetylated low density lipoproteins (LDL and acetyl-LDL) show an increased synthesis of PAI-1. Confluent EC monolayers were incubated for 16-18 hours in medium 199 with or without different concentrations of LDL and acetyl-LDL and PAI-1 antigen levels were measured in conditioned medium. LDL and acetyl-LDL increased the release of PAI-1 by EC in a concentration-dependent manner. The effect was specific for PAI-1 because tissue type plasminogen activator (t-PA) and expression of procoagulant activity were not affected by either lipoprotein. The observation that native and acetyl-LDL, which are known to interact with different receptors on EC, exert the same stimulatory effect on PAI-1 release rules out the possibility of an involvement of the LDL receptor in mediating this effect. Experiments carried out incubating native LDL in the presence of a monoclonal antibody against LDL receptor and using binding-defective LDL with a reduced affinity for the LDL receptor (∼50% with respect to normal LDL) further excluded an involvement of the classical LDL receptor in mediating the effect of the lipoproteins on PAI-1 synthesis by EC.

[Study of several proteins of the acute phase of surgical intervention]. / Indagine su alcune proteine della fase acuta nell'intervento chirurgico.

The aim of this study is to evaluate the behaviour of some proteins of acute phase (C reactive protein, alpha 1 acid glycoprotein, fibrinogen) in patients undergoing surgical operation. C reactive protein seems to be the most responsive to surgical trauma; alpha 1 acid glycoprotein reveals complications post-operation.

Increased synthesis of plasminogen activator inhibitor-1 by cultured human endothelial cells exposed to native and modified LDLs. An LDL receptor-independent phenomenon.

The effects of native and acetylated low density lipoproteins (LDLs and acetyl-LDLs, respectively) on the release of plasminogen activator inhibitor type 1 (PAI-1) by cultured human umbilical vein endothelial cells (ECs) were evaluated. LDL and acetyl-LDL incubated with ECs for 16-18 hours increased the PAI-1 antigen levels in conditioned medium. At a concentration of 100 micrograms/mL, LDL and acetyl-LDL increased PAI-1 by 10.8 and 12.0 ng/mL, respectively (p < 0.05 and p < 0.01 versus control). The increases in PAI-1 antigen levels exerted by the lipoproteins paralleled the changes in PAI-1 activity. The effect of LDL and acetyl-LDL was concentration dependent and specific for PAI-1 because tissue-type plasminogen activator and expression of procoagulant activity were not affected by either lipoprotein. In addition, total protein synthesis evaluated in [35S] methionine-labeled ECs was not affected, and studies with cycloheximide showed that the effect of LDL and acetyl-LDL on PAI-1 release was due to de novo protein synthesis. Experiments using the C7 monoclonal antibody against the LDL receptor and binding-defective LDL indicated that the effect of LDL on the synthesis of PAI-1 was not dependent on the interaction of the LDLs with their specific receptors. Finally, extensive oxidation of LDL prevented and even reversed the effect of LDL on PAI-1 release by ECs. It is concluded that LDL specifically increases the synthesis of PAI-1 by ECs with mechanisms that are not receptor mediated.