Assessing two-way interactions between cells and inorganic nanoparticles.

A safe and effective use of nanoparticles in biology and medicine requires a thorough understanding, down to the molecular level, of how nanoparticles interact with cells in the physiological environment. This study evaluated the two-way interaction between inorganic nanomaterials (INMs) and cells from A549 human lung carcinoma cell line. The interaction between silica and zinc oxide INMs and cells was investigated using both standard methods and advanced characterization techniques. The effect of INMs on cell properties was evaluated in terms of cell viability, chemical modifications, and volume changes. The effect of cells and culture medium on INMs was evaluated using dynamic light scattering (DLS), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), high performance liquid chromatography (HPLC), gas chromatography-mass spectroscopy (GC-MS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). No cytotoxic effect was detected in the case of silicon oxide INMs, while for high doses of zinc oxide INMs a reduction of cell survival was observed. Also, increased cell volume was recorded after 24 h incubation of cells with zinc oxide INMs. A better dimensional homogeneity and colloidal stability was observed by DLS for silicon oxide INMs than for zinc oxide INMs. SEM-EDS analysis showed the effectiveness of the adopted dispersion procedure and confirmed in the case of zinc oxide INMs the presence of residual substances derived from organosilane coating. HPLC and GC-MS performed on INMs aqueous dispersions after 24 h incubation showed an additional peak related to the presence of an organic contaminant only in the case of zinc oxide INMs. FTIR Chemical Imaging carried out directly on the cells showed, in case of incubation with zinc oxide INMs, a modification of the spectra in correspondence of phospholipids, nucleic acids and proteins characteristic absorption bands when compared with untreated cells. Overall, our results confirm the importance of developing new experimental methods and techniques for improving the knowledge about the biosafety of nanomaterials.

Randomised clinical trial: twice daily esomeprazole 40 mg vs. pantoprazole 40 mg in Barrett's oesophagus for 1 year.

BACKGROUND: Barrett's oesophagus is regarded as the most important risk factor for development of oesophageal adenocarcinoma. According to current guidelines, treatment should be limited to symptomatic Barrett's oesophagus. AIM: To evaluate the expression of Ki67, cyclooxygenase-2 (COX-2) and apoptosis in Barrett's oesophagus after 12 months of double-dose proton pump inhibitor therapy. The effectiveness of esomeprazole and pantoprazole was also compared. METHODS: Seventy-seven nondysplastic Barrett's oesophagus patients underwent baseline upper endoscopy. Patients were then randomised into two groups: one group was allocated to receive esomeprazole 40 mg b.d. and the other group pantoprazole 40 mg b.d. for 12 months. A follow-up endoscopy was performed at the end of treatment. Sixty-five of 77 patients agreed to undergo oesophageal manometry and 24-h pH-metry. Barrett's oesophagus biopsies, obtained at baseline and after treatment, were analysed using immunohistochemistry to assess Ki67 and COX-2 expression; apoptosis was evaluated using TUNEL. RESULTS: In the esomeprazole group, a significant decrease in Ki67 and COX-2 expression, as well as an increase in apoptosis, were observed (P < 0.05). By contrast, in the pantoprazole group Ki67, COX-2 and apoptosis did not vary significantly from baseline. By 24-h oesophageal pH-monitoring, a normal acid exposure time was recorded in patients treated with esomeprazole, while those allocated to pantoprazole displayed abnormal acid exposure (P < 0.05). CONCLUSIONS: Treatment of Barrett's oesophagus patients with high-dose esomeprazole, but not pantoprazole, promoted a decrease in proliferative markers, concomitantly with a decrease in apoptotic cell death. Moreover, esomeprazole allowed a better oesophageal acid control than pantoprazole.

Relationship between iron and protein content of dishes and polyphenol content in accompanying wines.

The traditional combination of wines and dishes is highly complex, elaborated and refined. The aim of this study was to investigate the possible relationship between the chemical composition of wines and dishes that determines their combination. We determined the content of total polyphenols in 56 wines. The content of total proteins, total lipids, kilocalories, sodium, potassium, calcium, copper and zinc were determined in 44 raw foods and 44 dishes. Nine gourmets independently chose three wines for each food. We correlated the content of the chemical constituents of foods with the phenol content of wines combined with each food by the gourmets. A significant positive correlation was obtained between the phenol content of wines and iron (r = 0.81, p < 0.0001) and total protein content (r = 0.66, p < 0.0001) of foods. Nine gourmets composing a second panel chose three wines for each dish. A significant positive correlation was also obtained between the phenol content of wines and iron (r = 0.69, p < 0.0001), total protein (r = 0.50, p < 0.0006) and potassium (r = 0.45, p < 0.002) in dishes combined with wines by the second panel of gourmets. Plant phenols decrease the intestinal absorption of iron and have antioxidant activity in the intestinal tract and elsewhere in the body. These positive effects compensate the negative antinutritional activity toward protein digestion. The traditional combination of wines and dishes appears to be very favorable since wines poor in phenols are combined with dishes poor in iron and/or proteins to minimize their possible antinutritional effects, while phenol-rich wines are combined with dishes rich in iron to decrease iron absorption and prandial peroxidative stress.

Release of 5-fluorouracil by biodegradable poly(ester-ether-ester)s. Part I: release by fused thin sheets.

The 5-fluorouracil release by biodegradable epsilon-caprolactone and L-lactide copoly(ester-ether-ester)s was tested. The drug-copolymer mixture was formed by fusion in thin sheets, which were dipped in Dulbecco's PBS for time intervals ranging from one hour to two months. Each experiment shows a fast initial release, which subsequently slows down and stops at a limiting value, depending on the copolymer composition. This behavior was attributed to an extraction of the drug present on the sheet surface, due only to its shape, and to hydrogen bonds between the drug and the copolymers. The results obtained lead to a possibility of using such copolymers as "time-delayed" drug-releasing systems, when formed in specimens with smaller surface-to-volume ratio, which could minimize the fast initial extraction.

Fibers by bioresorbable poly(ester-ether-ester)s as potential suture threads: a preliminary investigation.

Fibers made by a bioresorbable poly(epsilon-caprolactone)-block-poly(oxyethylene)-block-poly(epsilon-caprolactone) copolymer, having a number average molecular mass of about 200,000 Da and an average molar composition of 66% oxycaproyl units and 34% oxyethylene units, were melt-spun, with the aim at using them as suture threads. Their properties were investigated by the stress-strain test and by differential scanning calorimetry (DSC). The results obtained show that the properties of this material depend very strongly on the alignment of its macromolecules. In particular, the only partial alignment, obtainable by a relatively moderate drawing just after the extrusion, leads to values of elongation at break too high for use of the fibers as suture threads. The DSC analysis reveals interesting properties of the material, but also confirms their strong dependence on the extrusion procedure and on the mechanical treatment. In conclusion, the results of this preliminary study show that the spinning technique must be improved, and that further investigations are necessary to ascertain the possibility of using these poly(ester-ether-ester)s for the fabrication of suture threads.

Effect of chitosan and dextran on the properties of poly(vinyl alcohol) hydrogels.

Hydrogels are three-dimensional polymeric networks very similar to biological tissues and potentially useful as drug delivery systems. Poly(vinyl alcohol)-based hydrogels containing different amounts of dextran or chitosan were prepared using the freezing-thawing method. Repeated freezing-thawing cycles of a poly(vinyl alcohol) (PVA) aqueous solution lead to the formation of crystallites which act as cross-linking sites, and a hydrogel with a high capacity to swell is obtained. The effects of the two different polysaccharides on the properties of the obtained materials were investigated by differential scanning calorimetry, dynamic mechanical analysis and scanning electron microscopy. In addition the release with time of poly(vinyl alcohol) in aqueous medium, was monitored and evaluated. On the basis of the obtained results it seems that the presence of dextran favors the crystallization process of PVA, allowing the formation of a more ordered and homogeneous structure. Instead, chitosan seems to perturb the formation of PVA crystallites leading to a material with a less regular structure.

New composites of hydroxyapatite and bioresorbable macromolecular material.

Composite materials were prepared by mixing in different proportions of hydroxyapatite (HA) and poly(epsilon-caprolactone-oxyethylene-epsilon-caprolactone) block copolymer (PCL-POE-PCL) to produce a new resorbable material for biomedical applications. This material has proved to be very interesting for production of periodontal membranes. Mechanical properties are linearly proportional to the amount of HA introduced. Fourier transform infrared (FTIR) investigations have pointed out that HA is able to influence some close epsilon-caprolactone molecules to start its homopolymerization giving PCL with an end chain ionic bonding. HA grains are therefore surrounded by a film of PCL which grants close connection of HA grains within copolymeric matrix. This interface bond with PCL is, however, an interesting occurrence for preparations of HA/PCL composites.

Hydrogels based on chitosan and dextran as potential drug delivery systems.

The release of human growth hormone (GH) from bioartificial polymeric materials in the form of hydrogels, was measured in vitro for up to 3 weeks. Poly(vinyl-alcohol) (PVA) was blended, in different ratios, with two biological polymers, dextran and chitosan respectively. These blends were used to prepare hydrogels, using a freeze-thawing method. The hydrogels were loaded with GH, and their potential use as delivery systems was investigated. The release with time of PVA, in aqueous medium, was also monitored and evaluated. Scanning electron microscopy was used to investigate the structure of the hydrogels. The results obtained indicated that GH can be released from both dextran/PVA and chitosan/PVA hydrogels. The initial GH concentration used for sample loading affected the total quantity of GH released but not the pattern of release. The amount of GH released was affected by the content of the biological component. The percentage of PVA released was low but it was, however, related to the content of chitosan and dextran in the blends.

In vitro cytotoxicity testing of chitosan-containing polyelectrolyte complexes.

Two chitosan-containing polyelectrolyte complexes, chitosan-poly(acrylic acid) and chitosan-poly(styrenesulphonate), were synthesized by polymerizing acrylic acid and sodium styrenesulphonate in the presence of chitosan and chitosan hydrochloride, respectively. The complexes were studied by optical microscopy and tested for cytotoxicity by the Neutral Red uptake, Kenacid Blue R-Binding and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assays. The optical microscopy confirmed the differences in crystallinity and structure already found for the two polycomplexes by other characterization techniques. The cytoxicity tests showed different influences on the cell activity by the extracts of the two polyelectrolyte complexes. Such results were discussed and correlated to the different structures of the two materials.

T-lymphocyte tumor necrosis factor-alpha receptor binding in patients with Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease of the central nervous system (CNS), in which the cytokine network may be deranged, leading to an altered immunoregulation. Tumor necrosis factor(TNF)-alpha, a cytokine with pleiotropic neuroimmune effects, has specific receptors on human lymphocytes, as well as on other cell types, even in the CNS. The aim of the present study was to assay TNF-alpha binding on peripheral blood T cells from PD patients, as compared with healthy subjects. We found on T lymphocytes from parkinsonian patients significantly more TNF-alpha receptors than on those from controls (B (max): 637+/-23 vs. 131+/-6 (mean+/-S.E.M.) receptors/cell). Such TNF-alpha binding sites are of the same type in patients and healthy subjects (K(d): 66.8+/-5.1 vs. 70.7+/-5.6 (mean+/-S.E.M.) pM). These results are discussed in terms of PD immunopathogenesis, since it has been reported that activated T lymphocytes have increased amounts of TNF-alpha receptors.