ECIS based wounding and reorganization of cardiomyocytes and fibroblasts in co-cultures.

The crosstalk of two major heart cell groups, cardiomyocytes and fibroblasts, relies on direct electromechanical cellular coupling as well as indirect mechanical signal transmission through the surrounding viscoelastic extracellular matrix. Upon injury of cardiac tissue, this communication becomes unbalanced: fibrosis is initiated leading to increased collagen deposition, accompanied by an activation of fibroblasts - the key players of fibrosis. They undergo a reorganization or partial transformation to myofibroblasts during this process, which precedes scar formation within the infarcted heart in vivo. Here, we induce wound formation in an in vitro system as a model for these fibrotic conditions: we assessed the dynamics of wound healing in co-cultures of fibroblasts and myocytes upon targeted wound initiation using Electric Cell Substrate Impedance Sensing (ECIS) under optical control. We discovered distinct wound closure dynamics for mono- and co-cultures of myocytes and fibroblasts and observed a cessation of the contractile behavior for recovering cardiomyocyte cultures. We furthermore identified a change of cellular impedance for recovering fibroblasts and the presence of α-SMA, suggesting a partial transformation into myofibroblasts. This was concomitant with a modulation of connectivity, cell-substrate dynamics and membrane capacitance of all wounded cell cultures. Qualitatively, connexin 43 observation confirmed the ECIS trend found for cell-cell connectivity. Finally, we were able to validate the ECIS based wounding approach against an ECIS based barrier assay - the so-called electric fence. In particular the cell-cell connectivity and thus cell layer integrity dominates the healing dynamics within the two intrinsically different assays.

In vitro activity of ceftibuten at sub-inhibitory concentrations in comparison with other antibiotics against respiratory and urinary tract pathogens.

Some new features of the in vitro activity of ceftibuten, an oral third generation cephalosporin, have been studied in reference to respiratory and urinary tract pathogens included in its antibacterial spectrum. At 0.25XMIC (minimum inhibitory concentration) and 0.5XMIC levels, ceftibuten was able to affect the biofilm production in 2/3 of both Escherichia coli and Proteus mirabilis strains, and reduced the number of strains capable of adhering to epithelial cells by about 35% in comparison to the control. Surface hydrophobicity was also influenced by ceftibuten and the other drugs at 0.25-0.5XMIC. In general, no marked variation in the virulence traits of the pathogens studied were found by exposing bacteria to sub-MICs of ceftibuten. Plasmid loss (from 1.8 to 37.2%), and Flac transfer inhibition (about 30-50% reduction in the number of recombinants) were detected under the experimental conditions used. This study confirms the excellent antibacterial properties of ceftibuten by adding new information about the effects of this antibiotic against pathogens often involved in respiratory and urinary tract infections that may be treated with this compound, supporting the appropriate use of this cephalosporin.

Effects of long-term dumping of harbor-dredged material on macrozoobenthos at four disposal sites along the Emilia-Romagna coast (Northern Adriatic Sea, Italy).

Sediment from harbors of the Emilia-Romagna (Northern Adriatic Sea) were dredged and dumped in four disposal areas characterized by muddy bottoms. The long-term effects of the dumping on macrozoobenthic communities were investigated before and after 6 month, 8 month, 2 years and 4 years. The disposal of dredged material did not influence the granulometry and %TOC in the sediment, and no alterations in the structure of the macrobenthic communities were observed in the four areas. The lack of impact could be ascribed to the environmental characteristics and precautionary measures taken to minimize the effects of the dumping. It appears that: (1) the communities of the dumping areas are well adapted to unstable environments; (2) the sediments were disposed gradually and homogeneously over relatively large areas; Other factors that help to reduce the impact of sediment disposal are the low concentrations of contaminants in dredged materials and the similarity of sediment in the dredged and disposal areas. Off-shore discharge appears a sustainable strategy for the management of uncontaminated dredged sediments from the Northern Adriatic Sea harbors.

The effects of sand extraction on the macrobenthos of a relict sands area (northern Adriatic Sea): results 12 months post-extraction.

Sands for the nourishment of beaches along the Emilia-Romagna coast (northern Adriatic Sea) were dredged from an offshore area characterised by relict sands formed during the last Adriatic post-glacial transgression. The short-term effects of the sand extraction on macrozoobenthic communities were investigated before, during and 1, 6 and 12 months after dredging at three impacted stations and seven control stations. Sand extraction activities did not significantly influence the granulometry and %TOC in the sediment but caused almost complete defaunation at dredging stations. Yet, just 12 months after the extraction, the recolonisation of communities at the impacted stations was at an advanced stage. Unlike other studies on the effects of extraction of marine sand, no significant settlement of opportunistic species was observed. The limited impact of the sand extraction operation on the physical characteristics of the sediment and hydrological-sedimentary characteristics in the relict sand area should aid its rapid recovery and the restoration of the original community in a short period of time (2-4 years after dredging).