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ABSTRACT: The effects of thermal stimuli on intracellular calcium change and histamine releases in rat basophilic leukemia mast cells J. Appl. Phys. 111, 104701 (2012) Lectin-functionalized microchannels for characterizing pluripotent cells and early differentiation Biomicrofluidics 6, 024122 (2012) Oleic acid-enhanced transdermal delivery pathways of fluorescent nanoparticles Appl. Phys. Lett. 100, 213701 (2012) Quantum dynamics in continuum for proton transport—Generalized correlation JCP: BioChem. Phys. 6, 04B606 (2012) Quantum dynamics in continuum for proton transport—Generalized correlation
Applied Physics Letters 01/2011; 99(136):223701-134109. · 3.84 Impact Factor
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Simona Serini,
Valentina Donato,
Elisabetta Piccioni,
Sonia Trombino,
Giovanni Monego,
Amelia Toesca,
Idanna Innocenti, Mauro Missori,
Marco De Spirito,
Leonardo Celleno,
Elena Fasano,
Franco O Ranelletti,
Gabriella Calviello
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ABSTRACT: The dramatic increase in the incidence of nonmelanoma skin cancer over the last decades has been related to the augmented exposure to ultraviolet (UV) radiation (UVR). It is known that apoptosis is induced as a protective mechanism after the acute irradiation of keratinocytes, whereas apoptotic resistance and carcinogenesis may follow the chronic exposure to UVR. We found that not all the human keratinocytes lines studied underwent apoptosis following acute exposure to UVR (10-60 mJ/cm(2)). Whereas UVR induced apoptosis in the HaCaT cells, NCTC 2544 and nr-HaCaT cells showed apoptosis resistance. The cytokeratin pattern of the apoptosis-resistant cells indicated that they possessed a degree of differentiation lower than that of HaCaT cells. They also showed an enhanced expression of cyclooxygenase-2 (COX-2), an early marker of carcinogenesis in various tissues, including skin. n-3 polyunsaturated fatty acids have drawn increasing interest as nutritional factors with the potential to reduce UVR carcinogenesis, and since they are apoptosis inducers and COX-2 inhibitors in cancer cells, we investigated the ability of n-3 polyunsaturated fatty acids to influence the resistance to UVR-induced apoptosis in keratinocytes. We observed that docosahexaenoic acid (DHA) reverted the resistance of nr-HaCaT cells to UVR-induced apoptosis, increasing the Bax/Bcl-2 ratio and caspase-3 activity, and reduced COX-2 levels by inhibiting the expression of the human antigen R (HuR), a known COX-2 mRNA stabilizer in keratinocytes. The transfection of nr-HaCaT cells with HuR siRNA mimicked the proapoptotic effect of DHA. Overall, our findings further support the role of DHA as a suitable anticarcinogenic factor against nonmelanoma skin cancers.
The Journal of nutritional biochemistry 12/2010; 22(9):874-85. · 4.29 Impact Factor
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ABSTRACT: Von Willebrand factor (VWF) is a large multimeric adhesive glycoprotein, with complex roles in thrombosis and hemostasis, present in circulating blood and in secretory granules of endothelial cells and platelets. High shear stress triggers conformational changes responsible for both binding to the platelet receptor glycoprotein GpIb and its self-association, thus supporting the formation of platelet plug under flow. Ristocetin also promotes the interaction of VWF with GpIb and is able to induce platelet aggregation, and thus is largely used to mimic this effect in vitro. In this research paper, we followed the time course of VWF self-association in solution induced by ristocetin binding by light scattering and at the same time we collected atomic force microscopy images to clarify the nature of the assembly that is formed. In fact, this process evolves initially through the formation of fibrils that subsequently interact to form supramolecular structures whose dimensions would be capable of trapping platelets even in the absence of any degree of shear stress or interaction with external surfaces. This intrinsic property, that is the ability to self-aggregate, may be involved in some pathological settings that have been revealed in clinical practice.
Biophysics of Structure and Mechanism 11/2010; 39(12):1597-603. · 2.44 Impact Factor
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ABSTRACT: We have investigated the changes in the mechanical properties of the zona pellucida (ZP), a multilayer glycoprotein coat that surrounds mammalian eggs, that occur after the maturation and fertilization process of the bovine oocyte by using atomic force spectroscopy. The response of the ZP to mechanical stress has been recovered according to a modified Hertz model. ZP of immature oocytes shows a pure elastic behavior. However, for ZPs of matured and fertilized oocyte, a transition from a purely elastic behavior, which occurs when low stress forces are applied, towards a plastic behavior has been observed. The high critical force necessary to induce deformations, which supports the noncovalent long interaction lifetimes of polymers, increases after the cortical reaction. Atomic force microscopy (AFM) images show that oocyte ZP surface appears to be composed mainly of a dense, random meshwork of nonuniformly arranged fibril bundles. More wrinkled surface characterizes matured oocytes compared with immature and fertilized oocytes. From a mechanical point of view, the transition of the matured ZP membrane toward fertilized ZP, through the hardening process, consists of the recovery of the elasticity of the immature ZP while maintaining a plastic transition that, however, occurs with a much higher force compared with that required in matured ZP.
Biophysics of Structure and Mechanism 06/2009; 39(6):987-92. · 2.44 Impact Factor
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ABSTRACT: We have investigated the mechanical properties of the zona pellucida (ZP), a multilayer glycoprotein coat that surrounds mammalian eggs, using atomic force spectroscopy. The response of the membrane to mechanical stress has been reconstructed using a modified Hertz model. The transition from elastic behavior, which occurs when low stress forces are applied (characterized by a Young’s modulus E=(22±5) kPa ), toward plastic behavior is observed. The critical indentation necessary to induce plastic deformations occurs at δ<sub> yield </sub>=(550±50) nm . This high critical value, corresponding to two ZP layers, well supports the noncovalent long lifetimes of interactions that take place between constituent glycoproteins.
Applied Physics Letters 05/2009; · 3.84 Impact Factor
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ABSTRACT: Plants, algae, and their derivatives (paper, textiles, etc.) are complex systems that are chiefly composed of a web of cellulose fibers. The arrangement of solvents within the polymeric structure is of great importance since cellulose degradation is strongly influenced by water accessibility and external agents. In this paper we develop a model that is able to deconvolve the scattering contributions of both polymeric structures and solvent clusters trapped along the polymeric fibers. The surface morphology of cellulose fibers and the spatial distribution of water-filled pores and their dimensions have been recovered from small angle neutron scattering and atomic force microscopy data in function with paper degradation. In addition to providing a boost to the effort to preserve cellulose-supported material (included cultural heritage), the relevance of our model resides in the exploitation of a large number of biopolymer networks that are known to share structures similar to that of cellulose.
Physical Review E 04/2008; 77(4 Pt 1):041801. · 2.26 Impact Factor
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ABSTRACT: Zirconia, a biomaterial widely used in dentistry, has recently attracted much attention for its mechanical strength and toughness. Previously, its lack of mutagenic and carcinogenic power was reported. We describe here other essential aspects to be taken into account to define in vitro the biocompatibility of a material: the growth rate, viability, and adhesion capacity of normal stabilized cells growing on it. To this aim, immortalized RAT-1 fibroblasts, growing either on zirconia and on feldspatic (FE) ceramics were compared. In particular, the level of expression and the intra- and extra-cellular organization of fibronectin, a glycoprotein involved in cellular adhesion and migration during tissue repair, was analyzed. Fibroblasts cultured on zirconia showed a higher growth rate, and underwent necrosis at lower levels than cells on FE ceramic, whereas either materials did not stimulate apoptosis. Adhesion capacity of fibroblasts was evaluated measuring adherent cell nucleic acids with the fluorimetric CyQuant assay, and it was found significantly higher in cells cultured on zirconia than on FE ceramic. This finding may be explained by the higher and more precocious expression of the adhesion protein fibronectin observed by indirect immunofluorescence in fibroblasts on zirconia. Overall, the results suggest that zirconia, exerting low cytotoxicity and strongly inducing adhesion capacity, increases cellular growth rate of fibroblasts. All these features suggest that zirconia could represent a more suitable biomaterial than FE ceramic for prosthesis in dentistry.
Journal of Biomedical Materials Research Part A 01/2008; 86(4):959-68. · 2.63 Impact Factor
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ABSTRACT: Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose's supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.
Physical Review Letters 01/2007; 97(23):238001. · 7.37 Impact Factor
