Enrico Perrotta

PEG-templated mesoporous silica nanoparticles exclusively target cancer cells

Mesoporous silica nanoparticles (MSNs) have been proposed as DNA and drug delivery carriers, as well as efficient tools for fluorescent cell tracking. The major limitation is that MSNs enter cells regardless of a target-specific functionalization. Here we show that non functionalized MSNs, synthesized using a PEG surfactant-based interfacial synthesis procedure, do not enter cells, while a highly specific, receptor mediated, cellular internalization of folic acid (FOL) grafted MSNs (MSN-FOL), occurs exclusively in folate receptor (FR) expressing cells. Neither the classical clathrin pathway nor macropinocytosis is involved in the MSN endocytic process, while fluorescent MSNs (MSN-FITC) enter cells through aspecific, caveolae-mediated, endocytosis. Moreover, internalized particles seem to be mostly exocytosed from cells within 96 h. Finally, cisplatin (Cp) loaded MSN-FOL were tested on cancerous FR-positive (HeLa) or normal FR-negative (HEK293) cells. A strong growth arrest was observed only in HeLa cells treated with MSN-FOL-Cp. The results presented here show that our mesoporous nanoparticles do not enter cells unless opportunely functionalized, suggesting that they could represent a promising vehicle for drug targeting applications.

Ultrastructure and Comparative Morphology of Mouth-part Sensilla in Ground Beetle Larvae (Insecta, Coleoptera, Carabidae)

Abstract Labial and maxillary palps in 22 species of ground beetle larvae revealed the presence of four different types of sensilla: sensilla digitiformia, sensilla campaniformia, sensilla basiconica and sensilla chaetica. Using transmission electron microscopy techniques, the role of most of them was defined: sensilla campaniformia and sensilla chaetica are mechanoreceptors; while sensilla basiconica are chemoreceptors. Sensilla digitiformia can be both mechanoreceptors and chemoreceptors, though hygroreception may also be postulated on the basis of their abundance on the mouthparts of some hygrophilous species that depend on damp or wet patchy biotopes/seasons. The number and location of the sensory structures has been found to vary among the investigated taxa. The differences are related to the larval behavioural types, and are an adaptive response to different lifestyles, feeding habits and use of space.

Amine-functionalized SBA-15 in poly(styrene-b-butadiene-b-styrene) (SBS) yields permeable and selective nanostructured membranes for gas separation

New nanostructured hybrid membranes for gas separation have been prepared and characterized for the first time in the literature by using a block copolymer, poly(styrene-b-butadiene-b-styrene) (SBS), and aminated SBA-15. Short mesopore channels, platelet SBA-15 particles with a high surface density of 3-aminopropyl grafts (3.8 nm−2) and modest surface area reduction (45%) were prepared, characterized and used as a filler. The gas transport characterization of the hybrid membranes indicates that with a 10 wt% content of aminated filler, outstanding performances in terms of selectivity and permeability for the CH4/N2 and the CO2/N2 gas pairs can be obtained. In particular, the CH4/N2 ideal selectivity of 7.3 is higher than the values of the existing block co-polymers used for this separation and of mixed matrix membranes described to date in the literature. Membranes with such a high separation factor may enable the exploitation of natural gas with high N2 content and increase the amount of methane that can be economically recovered. The combination of the CO2/N2 ideal selectivity of 53 with a CO2 permeability of 173 Barrer demonstrates that the new hybrid membranes prepared in this study deserve further attention as a practical commercial solution also for the post-combustion capture of carbon dioxide. Finally, the small and flat particles dispersed in the polymer lend themselves to the fabrication of thin industrial membranes with enhanced productivity.

iNOS induction and PARP-1 activation in human atherosclerotic lesions: an immunohistochemical and ultrastructural approach.

BACKGROUND Several lines of clinical and experimental evidence have demonstrated that reactive oxygen species and nitrogen species are generated in unregulated amounts during diverse cardiovascular disorders. It has been previously reported by our group and others that augmented expression of nitric oxide synthase isoforms is associated with human atherogenesis and that the activity of the enzymes in an atherosclerotic environment may promote the formation of peroxynitrite. Among the downstream mechanisms triggered by oxidants, poly(ADP-ribose) polymerase-1 activation has recently been implicated in the pathogenesis of acute and chronic myocardial dysfunction, diabetes, hypertension, aging, and various forms of shock. METHODS Based on these observations, we performed immunohistochemical and immunogold labeling analyses to evaluate the expression profile and the subcellular localization of inducible nitric oxide synthase and poly(ADP-ribose) polymerase-1 in healthy and atherosclerotic human aortae. RESULTS We have demonstrated that inducible nitric oxide synthase colocalizes with poly(ADP-ribose) polymerase-1 within vascular cells of atherosclerotic human aortae. We have reported for the first time, to our knowledge, the ultrastructural localization of poly(ADP-ribose) polymerase-1 within the nuclei of lesional smooth muscle cells. Finally, we have evidenced that poly(ADP-ribose) polymerase-1 induction within cells of the diseased aorta strongly correlates with alterations in mitochondrial morphology. CONCLUSIONS Our data imply the possibility of a significant role for cross-talk between inducible nitric oxide synthase and poly(ADP-ribose) polymerase-1 in human atherosclerotic lesions. We conclude that the prooxidant milieu of the plaque might exert damaging effects on mitochondria via a poly(ADP-ribose) polymerase-1-mediated mechanism since the absence of the enzyme results in a corresponding lack of changes in mitochondrial morphology. The present report may open avenues for further researches that could have important therapeutic consequences for the treatment of atherosclerosis and its clinical sequelae.

Morphological and functional variations of Leydig cells in testis of the domestic pig during the different biological stages of development.

The relationship of morphometrical and androgen receptor evaluations of the main testicular interstitium cellular element (Leydig cells) in the domestic pig provided interesting numerical and morphological features during the different aging stages. As early as 25 days (a period in which the pig is sexually immature) there was a low number of Leydig cells (1.46 x 10(8)) with respect to a 78% and 35% increase in the adult (2.48 x 108) and aged (1.78 x 10(8)) animal, respectively. Interestingly, when the volume density of Leydig cells was considered, the average volume of these cells seemed to be high (75%) in the aged pig with respect to the young immature animal whereas a lower increase (27%) was observed for the adult animal. Moreover, the evaluation of testosterone receptor binding sites in the testis at the various stages of development also displayed a differentiated pattern since elevated testosterone receptor binding levels of the high dissociation affinity type were obtained for the adult pig. Thus, from the combined morphological variations of Leydig cells and testosterone receptor binding activity, it appears that this androgenic receptor component exerts distinct autocrine effects on the different functional features of some testicular tissue constituents at the different aging stages of the domestic pig.

MnSOD expression in human atherosclerotic plaques: an immunohistochemical and ultrastructural study

BACKGROUND Over the last decades, the role of oxidative stress in atherosclerosis has become well established, and considerable effort has been made to understand the mechanism of action of free radicals within the cardiovascular system. Conversely, relatively little attention has been directed towards the characterization of the antioxidant status of the arterial wall under disease state. Among the antioxidant enzymes, the manganese-dependent and mitochondria-specific isoform of SOD (MnSOD) represents the first line of defense against superoxide radicals attack. To date, the pathological significance of MnSOD in atherosclerosis is still unclear with conflicting data published. METHODS In the present study, we used immunohistochemical techniques at the light and electron microscopy level in combination with biochemical assays to localize and characterize the activity and expression profiles of MnSOD in healthy and atherosclerotic human aorta. RESULTS MnSOD has been found to be highly expressed in the atherosclerotic plaques where specifically localized to the foam cells of the lipid-rich regions but not to other (nonfoamy) cell types. No ultrastructural evidence of apoptosis, such as chromatin condensation and membrane blebbing, has been observed in MnSOD-expressing cells. The up-regulation of MnSOD at the protein level has been associated with a parallel, significant increase of its catalytic activity. CONCLUSIONS Our data demonstrate that MnSOD is not negatively regulated by the prooxidative and proinflammatory environment of the plaque and evidence a regional and cellular selectivity of MnSOD protein expression under disease state. We suggest that MnSOD induction might represent a protective response against the cytotoxic effect of oxidized low-density lipoprotein.

Ultrastructural Analysis and Electron Microscopic Localization of Nox4 in Healthy and Atherosclerotic Human Aorta

During diverse pathological conditions, vascular smooth muscle cells (SMCs) characteristically change from a quiescent, contractile phenotype to a proliferative, synthetic state, migrate toward the intima, and synthesize excess extracellular matrix. Although reactive oxygen species (ROS) are generally considered to be toxic to cells, recent evidence suggests that they may also modulate multiple signaling pathways. The vascular system contains several sources of ROS, among which NADPH oxidases (NOXes) have been shown to take an important part in the regulation of cell function, with effects on growth and proliferation. In the present study, the authors investigate the ultrastructural features of SMCs and the expression profile of Nox4 in healthy and atherosclerotic human aorta to explore the possibility of a relationship between Nox4 and SMCs differentiation state. The data extend at the level of immunoelectron microscopy previous observations, demonstrating for the first time the precise distribution and the differential expression of Nox4 in the morphologically distinct SMC types of healthy and diseased human aorta.

Membrane Operations for Industrial Applications

A resource-intensive industrial development, particularly in some Asian countries, characterized the last century. Its main causes can be ascribed to the significant elongation of life expectation, and to the overall increase in the standards characterizing the quality of life. The drawback of these positive aspects is the emergence of problems related to the industrial development: water stress, the environmental pollution, and the increase of CO2 emissions into the atmosphere.

Ultrastructure of Popliteal Vein Aneurysm

The term aneurysm is used to indicate a permanent and irreversible localized vascular dilatation that involves all three layers of the blood vessel wall. It may develop in any part of the circulatory system, including veins, and its history, presentation, and management differ depending on the location. A venous aneurysm is defined as a solitary area of fusiform or saccular dilatation occurring in the course of a major vein or connected by a single channel to a major venous structure. The lower extremities are the most frequently affected, with the popliteal vein being the most common site. Although different theories have been advanced, the etiology of the disease remains uncertain. Mechanical stress and/or degenerative changes within the vein wall are believed to represent the most likely causes of venous aneurysm. To date, there are only a few publications dealing with the histological appearance of popliteal vein aneurysm, and no studies that specifically describe its ultrastructural details have been published to our knowledge. In an attempt to fill this gap and to provide better insights into the pathophysiological mechanisms possibly involved in aneurysmal venous disease, we describe the fine structure of popliteal vein wall and valve in health and disease using both scanning and transmission electron microscopy.