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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.

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.

The features of implant devices and the reactions of bone-derived cells to foreign surfaces determine implant success during osseointegration. In an attempt to better understand the mechanisms underlying osteoblasts attachment and spreading, in this study adhesive peptides containing the fibronectin sequence motif for integrin binding (Arg-Gly-Asp, RGD) or mapping the human vitronectin protein (HVP) were grafted on glass and titanium surfaces with or without chemically induced controlled immobilization. As shown by total internal reflection fluorescence microscopy, human osteoblasts develop adhesion patches only on specifically immobilized peptides. Indeed, cells quickly develop focal adhesions on RGD-grafted surfaces, while HVP peptide promotes filopodia, structures involved in cellular spreading. As indicated by immunocytochemistry and quantitative polymerase chain reaction, focal adhesions kinase activation is delayed on HVP peptides with respect to RGD while an osteogenic phenotypic response appears within 24 h on osteoblasts cultured on both peptides. Cellular pathways underlying osteoblasts attachment are, however, different. As demonstrated by adhesion blocking assays, integrins are mainly involved in osteoblast adhesion to RGD peptide, while HVP selects osteoblasts for attachment through proteoglycan-mediated interactions. Thus an interfacial layer of an endosseous device grafted with specifically immobilized HVP peptide not only selects the attachment and supports differentiation of osteoblasts but also promotes cellular migration.

Thymosin-beta 4 (T beta 4) is a G-actin sequestering peptide involved in regeneration and remodeling of injured tissues. In this work, we have designed and synthesized three peptide sequences containing the N-terminus (TYB4-n), the central part (TYB4-i) or the C-terminus (TYB4-c) of T beta 4. All fragments are overlapping on the main central binding actin site. After a structural characterization, we have evaluated in vitro and in vivo their pro-angiogenic effects. The results of this study have shown that: (i) each fragment reproduces the native conformation; (ii) T beta 4-derived peptides exert both in vitro and in vivo pro-angiogenic effects; (iii) their in vitro effect seem to be related to the activation of several signaling pathways and is positively modulated by the N-terminus of T beta 4. (C) 2011 Elsevier Inc. All rights reserved.

Biomimetic polymer nanofibers of poly(e-caprolactone) and poly(L-lactide–caprolactone) copolymer were prepared by electrospinning. Modifications of the polymer nanofibers aimed at improving their biomimetic properties were performed by two different routes: (1) immobilization of an adhesion peptide, which mimicked the adhesion sequence of the extracellular matrix protein fibronectin, on the polymer surface and (2) incorporation of self-complementary oligopeptides, which showed alternated hydrophilic and hydrophobic side chain groups and was capable of generating extended ordered structures by self-assembling, into the polymer nanofibers. The structure of the polymer/peptide nanofibers was investigated by X-ray photoelectron and Fourier transform infrared spectroscopies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Covalent attachment of adhesive peptides to biomaterials surfaces can result in the formation of a bioactive and biomimetic surface. We have demonstrated that titanium surfaces grafted with adhesion peptides, reproducing sequences of fibronectin and vitronectin, can increase osteoblast adhesion compared to non-treated surfaces. We now extend our investigation to peptide immobilization on glass for studying human osteoblast adhesion and spreading. Silanization was used to anchor adhesion peptides to the glass surface through a selective or a non-selective immobilization. Investigated samples were analysed by XPS spectroscopy. Comparison between the results obtained using two different peptides and applying selective and non-selective immobilization will be discussed.

The immobilization of an oligopeptide, mimicking the adhesion sequence of fibronectin, on the surface of polymer films prepared by electrospinning was investigated by XPS spectroscopy. Films of polycaprolactone (PCL) and poly(l‐lactide‐caprolactone) [P(LLA‐CL)] were prepared by electrospinning onto aluminium substrates. A modified adhesion peptide containing a photoreactive group was immobilized on the surface of the polymer nanofibers by incubation in peptide solution and subsequent UV irradiation. XPS analysis yield evidence of successful peptide immobilization on the polymer surface; the amount of immobilized peptide increases with the concentration of the mother solution.

Bioactive molecules have been proposed to promote beneficial interactions at bone-implant interfaces for enhancing integration. The main objective of this study was to develop novel methods to functionalize oxidized titanium surfaces by the covalent immobilization of bioactive peptides, through selective reaction involving single functional groups. In the first protocol, an aminoalkylsilane was covalently linked to the Ti oxide layer, followed by covalent binding of glutaric anhydride to the free NH(2) groups. The carboxylic group Of glutaric anhydride was used to condense the free N-terminal group of the side-chain protected peptide sequence. Finally, the Surface was treated with trifluoroacetic acid to deprotect side-chain groups. In the second protocol, the peptide was directly anchored to the Ti oxide surface via UV activation of an arylazide peptide analogue. X-ray photoelectron spectroscopy analyses confirmed that modifications induced onto surface composition were in agreement with the reactions performed. The peptide density of each biomimetic Surface was determined on the basis of radiolabeling and XPS derived reaction yields. The in vitro cellular response of the biomimetic surfaces was evaluated using a primary human osteoblast cell model. Cell adhesion, proliferation, differentiation, and mineralization were examined at initial-, short-, and long-time periods. In was shown that the biomimetic surface obtained through photoprobe-marked analogue that combines an easily-performed modification provides a favorable surface for an enhanced cellular response.

Nel lavoro vengono presentati i risultati di una serie di prove sperimentali condotta su tre geometrie di giunti rivettati a doppia sovrapposizione in materiale composito soggetti a fatica con rapporto di carico R=0. Il materiale considerato per la realizzazione dei giunti è un laminato unidirezionale quasi isotropo con matrice in resina epossidica e rinforzo in fibra lunga di carbonio T300 (Vf = 60%) disposto in 8 strati con lay-up bilanciato e simmetrico [0°,45°,-45°, 90°]s e spessore complessivo medio di 1.5 mm. Le prove, almeno tre per ciascuna geometria, sono state condotte in controllo di carico alla frequenza di 1 Hz su di una macchina servo-idraulica Instron 8033 ed hanno portato alla determinazione della curva di vita a fatica del componente ed alla visualizzazione dei modi di rottura. Le diverse configurazioni dei giunti e le loro dimensioni sono il risultato di considerazioni riportate in letteratura e di precedenti indagini sperimentali effettuate su provini con intaglio per verificare l'influenza delle dimensioni del foro sul materiale e, nel caso di due intagli vicini, la loro reciproca influenza. Le prove di caratterizzazione quasi statica e a fatica sul componente hanno visualizzato un unico modo di rottura comune per tutti i tipi di geometria e modalità di carico e hanno dimostrato che, per una ampiezza a fatica decrementata almeno del 30% rispetto al carico ultimo di rottura quasi-statico della giunzione (Fult), il componente appare completamente integro a 106 cicli di vita indipendentemente dal tipo di configurazione considerata. Le caratteristiche del materiale ed del suo lay-up sembrano risultare dunque fondamentali per la durata di vita del componente, a prescindere dalla particolare geometria considerata.