Search

Newly synthesized fluorescent nanoparti- cles of 2-amino-6-ethoxy-4-[4-(4-morpholinyl)phenyl]-3, 5-pyridinedicarbonitrile have been developed and characterized for possible applications as security marker in paper documents. Nanoparticles have been prepared by reprecipitation in water under sonication. The size and the shape of these nanoparticles, charac- terized by light scattering and atomic force micros- copy, have been found to be highly dependent on sonication power. Typical sizes range from tens to hundreds of nanometers. Furthermore, a remarkable increase in the fluorescence yield has been observed as nanoparticles sizes decrease. Finally, all of the above features, together with the striking stability of optical and mechanical properties over the course of months, allow for straightforward applications that rely on strong and stable fluorescence such as marking impor- tant or valuable documents.

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. Here we show a model based on small angle neutron scattering (SANS) data able to deconvolve the scattering contributions of both polymeric structures and solvent clusters trapped along the polymeric fibers. 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.

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 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 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.

Ischemic heart disease is the leading cause of serious morbidity and mortality in Western society. One of the therapeutic approaches is based on the use of thrombolitic drugs that promote clot lysis. Even if the mechanisms leading to clot lysis are not completely understood, it is widely accepted that they depend on the complex biochemical reactions that occur among fibrin fibers and fibrinolitic agents, and by their ready diffusion into the fibers. Here we investigate the effects of specific anions on the architecture of protofibrils within fibrin fibers in fibrin gels prepared in a para-physiological solution. The results obtained through small-angle X-ray scattering (SAXS) demonstrate that the characteristic axial and longitudinal repeat distances among protofibrils are strongly affected by the action of Cl- and F- anions.

Ischemic heart disease, which results from occlusion of one of the major coronary arteries as a consequence of thrombi and atherosclerotic plaque, continues to be the leading cause of morbidity and mortality in Western society, while stroke is the second leading cause of death worldwide. Nowadays, in addition to prevention, it is possible to treat atherosclerotic plaque by means of invasive endovascular procedures. With the advent of thrombolytic agents that favor clot lysis, treatment of patients suffering from thromboembolic diseases is greatly improved. Clots are composed of a three-dimensional fibrous network, known as fibrin gel; it is within the scaffold of this that platelets and other blood constituents get trapped, thus giving rise to the haemostatic plug. The structure of fibrin gel depends upon the polymerization conditions of fibrinogen, a glycoprotein present in the plasma of vertebrates. The thrombin-catalyzed polymerization process is usually modelled through the occurrence of a number of distinct steps that lead to the formation of fibrin monomers, which subsequently undergo polymerization to produce oligomers called protofibrils. Lateral aggregation of protofibrils forms fibers and the branching of fibers that takes place during the association of protofibrils creates the final fibrin network. The chief factor responsible for clot lysis rate is the intrinsic permeability of the fibrin network and of the individual fibers to proteolytic agents. The diffusional access from outside to proteases involved in fibrinolysis is not yet fully understood For this reason, further knowledge of fibrin network architecture and of the packing arrangement of protofibrils would be desirable. Here we present the results of a combined Small Angle Neutron and X-ray scattering study of the packing arrangement of protofibrils. For the first time characteristic fibrils distance are related to the water trapped among fibrils and thus to space available to thrombolytic agent

a-crystallin is a protein that plays several relevant physiological roles (i.e is the major constituent of human lens or help in maintain the correct folding of several protein) all of them affected by the occurrence of aggregation. a-crystallin supramolecular aggregation, induced by generating heat-modified a-crystallin forms, has been investigated over a range of temperature between 30 C and 60 C by means of static and dynamic light scattering and atomic force microscopy. Aggregation, after the formation of first clusters or basic aggregation units, can be described as a cluster-cluster aggregation similar to that of colloidal particles. Below a temperature TC 1⁄4 45 C, after a large lag time needed to form the first clusters, a fast, diffusion limited, aggregation can be observed. Above TC we observe a faster lag time followed by a slow aggregation. Correspondingly the temperature dependence of aggregation rates display an abrupt discontinuity at TC . This discontinuity and the different kinetics of aggregation shed new light in the pathogenesis of the human eye lens cataract assigning a key role to the heat modified form of a-crystallin that markedly protect from aggregation preserving the transparency of the lens.

a-crystallin is a protein that plays several relevant physiological roles (i.e is the major constituent of human lens or help in maintain the correct folding of several protein) all of them affected by the occurrence of aggregation. a-crystallin supramolecular aggregation, induced by generating heat-modified a-crystallin forms, has been investigated over a range of temperature between 30 C and 60 C by means of static and dynamic light scattering and atomic force microscopy. Aggregation, after the formation of first clusters or basic aggregation units, can be described as a cluster-cluster aggregation similar to that of colloidal particles. Below a temperature TC ¼ 45 C, after a large lag time needed to form the first clusters, a fast, diffusion limited, aggregation can be observed. Above TC we observe a faster lag time followed by a slow aggregation. Correspondingly the temperature dependence of aggregation rates display an abrupt discontinuity at TC . This discontinuity and the different kinetics of aggregation shed new light in the pathogenesis of the human eye lens cataract assigning a key role to the heat modified form of a-crystallin that markedly protect from aggregation preserving the transparency of the lens.

a-crystallin is a protein that plays several relevant physiological roles (i.e is the major constituent of human lens or help in maintain the correct folding of several protein) all of them affected by the occurrence of aggregation. a-crystallin supramolecular aggregation, induced by generating heat-modified a-crystallin forms, has been investigated over a range of temperature between 30 C and 60 C by means of static and dynamic light scattering and atomic force microscopy. Aggregation, after the formation of first clusters or basic aggregation units, can be described as a cluster-cluster aggregation similar to that of colloidal particles. Below a temperature TC ¼ 45 C, after a large lag time needed to form the first clusters, a fast, diffusion limited, aggregation can be observed. Above TC we observe a faster lag time followed by a slow aggregation. Correspondingly the temperature dependence of aggregation rates display an abrupt discontinuity at TC . This discontinuity and the different kinetics of aggregation shed new light in the pathogenesis of the human eye lens cataract assigning a key role to the heat modified form of a-crystallin that markedly protect from aggregation preserving the transparency of the lens.

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.

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(R) 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.