SilkBridge™: a novel biomimetic and biocompatible silk-based nerve conduit.

Silk fibroin (Bombyx mori) was used to manufacture a nerve conduit (SilkBridge™) characterized by a novel 3D architecture. The wall of the conduit consists of two electrospun layers (inner and outer) and one textile layer (middle), perfectly integrated at the structural and functional level. The manufacturing technology conferred high compression strength on the device, thus meeting clinical requirements for physiological and pathological compressive stresses. In vitro cell interaction studies were performed through direct contact assays with SilkBridge™ using the glial RT4-D6P2T cells, a schwannoma cell line, and a mouse motor neuron NSC-34 cell line. The results revealed that the material is capable of sustaining cell proliferation, that the glial RT4-D6P2T cells increased their density and organized themselves in a glial-like morphology, and that NSC-34 motor neurons exhibited a greater neuritic length with respect to the control substrate. In vivo pilot assays were performed on adult female Wistar rats. A 10 mm long gap in the median nerve was repaired with 12 mm SilkBridge™. At two weeks post-operation several cell types colonized the lumen. Cells and blood vessels were also visible between the different layers of the conduit wall. Moreover, the presence of regenerated myelinated fibers with a thin myelin sheath at the proximal level was observed. Taken together, all these results demonstrated that SilkBridge™ has an optimized balance of biomechanical and biological properties, being able to sustain a perfect cellular colonization of the conduit and the progressive growth of the regenerating nerve fibers.

[Lack of doctors, but for what System? Shortage of clinicians in Italy and Lombardy and reflections on structural constrains in training]. / Carenza di medici: ma per quale SSN? Dati, riflessioni e proposte dalla formazione.

A lack of physicians is a major threat in many health care systems. Italy is coping with this problem, by increasing the number of residency training positions for medical graduates. Nevertheless, analysis of data and a critical review of organisational aspects of the system seem to suggest that structural changes are also needed. Eight areas are discussed: 1. The (very high) age of physicians in the country; 2. The (problematic) organisation of the health care delivery system; 3. The (uneven) distribution of residency training positions across the regions; 4. The (inadequate) mix of workforce between physicians and nurses; 5. The (biased) preferences for choosing a medical specialty; 6. The (emblematic) case of training for Gps; 7. The (unprecedent) growth of life expectancy and comorbidity; 8. The (absence of a) plan and method for recruiting workforce in health care at national level. The authors conclude that the solution for the lack of medical specialists is less a matter of increasing the number of residency training positions and more a matter of solving some structural constraints of the system. Solutions might have to do - for instance - with the introduction of the recognition of the professional role of physicians in residency training (especially for GPs - like in UK). Another aspect to be taken in consideration is also the professional role and competencies of nurses, that could be widened.

Conformational flexibility of lipase Lip1 from Candida rugosa studied by electronic spectroscopies and thermodynamic approaches.

We have used second-order orthogonal designs to obtain empirical models that describe the combined effect of pH and temperature on the secondary structure of a lipase (Lip1) from Candida rusosa. The equations that describe lipase conformational flexibility were derivated from the enzyme alpha helix fraction obtained from the experimental matrix. The thermal unfolding of lipase at different pH values was followed by measuring the circular dichroism signal as a function of temperature over a temperature range of 20-80 °C. The results showed a melting temperature of 58.9 °C at pH 5.5, while at pHs 7.0 and 8.6, the temperature values were 50.2 °C and 36.1 °C respectively. The optimum experimental conditions of conformations with high content of alpha helix were found at high temperature and pH, both at zero time and at one-hour incubation time of enzyme. Important variations in the enzyme secondary structure were induced for the pH and temperature. In contrast, minor changes were observed during the incubation time. This behaviour suggests that the medium pH induces a modification in the enzyme secondary structure and not due to a result of a progressive denaturation process. From the values of thermodynamic functions at different pHs, the system at initial state of unfolding process is previously disordered by the pH effect.