After the earthquake that stroke the city of L’Aquila during the night of April 6th 2009, many historical buildings at the city centre were severly damaged. Nevertheless many others survived the seismic event with only local damages, showing a good mechanical behaviour against vertical and horizontal actions. In order to continue preserving these buildings, a careful investigation is necessary before applying any repair technique, new or traditional to understand the past design practices for building durable and safe structures. In order to understand the structural behaviour of the church of St. Biagio in L’aquila, an extensive diagnostic investigation based on non-destructive and minor destructive techniques was carried out by the authors. The paper describes mainly the applied methodology which can produce some guidelines to be followed in the future study of other Cultural Heritage (C. H.) buildings hit by the earthquake.

The paper presents the case study of the "Basilica dei Frari" in Venice for which a non linear numerical analysis has been recently performed in order to assess its structural conditions. In fact, from the end of its construction, in the XIV century, the building suffered from structural deteriorations mainly due to settlements affecting the bell-tower. A main structural intervention was carried out at the beginning of the XX century, aimed at stopping the outward tilting process of the tower. The intervention was so effective that it induced an opposite effect on the tower, which started to rotate towards the cathedral. Several studies were carried out since then to evaluate the interaction between tower and church, including in recent years structural monitoring and numerical modelling, besides a strengthening intervention consisting in soil micro-fracturing. A non linear numerical model of the church-tower complex was implemented and compared to the outcomes of the available experimental data (monitoring, investigations), also considering the historical process leading to the present day conditions. To gain reliable settlement damage predictions it was necessary to adopt tensile-softening crack models in the numerical studies and perform non linear analyses able to trace the complete response of the structure. The aim of the modeling was also, besides the assessment of the structural conditions of the complex, to predict the structural effects of the physical "separation" between tower and cathedral.

In this work, a bioartificial system consisting of VEGF-loaded porous silica gel and myoblasts cultured on acellular diaphragmatic matrix (ADM) has been implanted to repair a surgically created diaphragmatic defect in Lewis rats. ADMs exerted a strong angiogenic response on chorio-allantoic membrane. Cytotoxicity, VEGF release and matrix erodibility in vitro tests demonstrated that the silica support was nontoxic and that the VEGF bioactivity was maintained after matrix entrapment and it was released within a timeframe that can be modulated by synthesis parameters. Different grafts composed by ADMs with and without autologous male myoblasts or/and VEGF-loaded porous silica gel have been implanted to repair previously created diaphragmatic defects in female Lewis rats. Patches composed of ADMs and myoblasts appeared well preserved until 8 weeks, and contained multinucleated cells and cholinergic fibers. At 8 weeks, the implanted cells were still present inside the patches. The disappointing results obtained when VEGF was delivered by porous silica gel were probably due to an abnormal angiogenic response following an excess of local growth factor concentration. Taken together, these results confirmed that our matrices contained biologically active angiogenic factors which were per se sufficient to induce neo-vessels formation, thus allowing the survival of implanted myoblasts.

Muscular dystrophies and neuromuscular disorders are characterized by progressive muscle wasting, and are significant health issues. We used mesenchymal stem cells (MSCs) isolated from human umbilical cord blood (UCB) capable of differentiating into various connective tissue lineages, and studied their myogenic potential. We injected 106 UCB-MSCs into a rat tibialis anterior model of muscle injury, caused by bupivacaine hydrochloride injection. The MSCs, labeled with green fluorescent protein (GFP), engrafted into the muscle after 1 week and stained positive for the early myogenic regulatory factors Myf-5 and MyoD. After 2 weeks, we noted striations of A and I bands showing the presence of sarcomeres in fibers containing UCB-MSCs. The skeletal muscle appeared intact by histological analysis, and the presence of MSCs was confirmed by immunostaining with HLA-A2 antibody, a human specific class I histocompatibility molecule. Expression of Myf-5, MyoD, and sarcomeric tropomyosin, a protein of actin filament was detected. There was no immunological response against the engrafted cells, and no immunosuppressive therapy was used. These results suggest that human UCB-MSCs are able to differentiate towards the myogenic lineage and to play a role in vivo during the muscle regenerative process. Supported by University of Padova, Cariparo Foundation, Italy, and the Coriell Institute.

To obtain a valuable treatment of congenital muscle defect, cell-matrix constructs composed of satellite cell-derived myoblasts (XY karyotype) seeded on muscle acellular matrices were used to repair a previously created full-thickness defect of abdominal wall of 18 1-month-old female Lewis rats. Acellular abdominal matrices, obtained by a detergent-enzymatic method, were positive for both basic fibroblast growth factor and transforming growth factor-beta, and were able to support in vitro cell adhesion. All animals survived the surgery, without signs of infection or implant rejection, and were humanely killed at 1, 3, or 9 months after surgery. The implants appeared well preserved, were integrated in the host tissue, and maintained their original dimension and thickness until 9 months. Vesicular acetylcholine transporter was expressed on the surface of muscle fibers from 1 month postsurgery. Finally, implanted male myoblasts were present inside the patches until 9 months, as demonstrated by the expression of SrY mRNA and by the presence of Y chromosome probe signal. These results allow us to conclude that cell-matrix constructs could represent a promising approach to the repair of muscle defects, because they are repopulated in vivo by skeletal muscle cells and nervous elements and maintain their structural integrity over the long term.