Innovative Poly (Vinylidene Fluoride) (PVDF) Electrospun Nanofiber Membrane Preparation Using DMSO as a Low Toxicity Solvent.

Electrospinning is an emerging technique for the preparation of electrospun fiber membranes (ENMs), and a very promising one on the basis of the high-yield and the scalability of the process according to a process intensification strategy. Most of the research reported in the literature has been focused on the preparation of poly (vinylidene fluoride) (PVDF) ENMs by using N,N- dimethylformamide (DMF) as a solvent, which is considered a mutagenic and cancerogenic substance. Hence, the possibility of using alternative solvents represents an interesting approach to investigate. In this work, we explored the use of dimethyl sulfoxide (DMSO) as a low toxicity solvent in a mixture with acetone for the preparation of PVDF-ENMs. As a first step, a solubility study of the polymer, PVDF 6012 Solef®, in several DMSO/acetone mixtures was carried out, and then, different operating conditions (e.g., applied voltage and needle to collector plate distance) for the successful electrospinning of the ENMs were evaluated. The study provided evidence of the crucial role of solution conductivity in the electrospinning phase and the thermal post-treatment. The prepared ENMs were characterized by evaluating the morphology (by SEM), pore-size, porosity, surface properties, and performance in terms of water permeability. The obtained results showed the possibility of producing ENMs in a more sustainable way, with a pore size in the range of 0.2-0.8 µm, high porosity (above 80%), and water flux in the range of 11.000-38.000 L/m2·h·bar.

Group I Paks support muscle regeneration and counteract cancer-associated muscle atrophy.

BACKGROUND: Skeletal muscle is characterized by an efficient regeneration potential that is often impaired during myopathies. Understanding the molecular players involved in muscle homeostasis and regeneration could help to find new therapies against muscle degenerative disorders. Previous studies revealed that the Ser/Thr kinase p21 protein-activated kinase 1 (Pak1) was specifically down-regulated in the atrophying gastrocnemius of Yoshida hepatoma-bearing rats. In this study, we evaluated the role of group I Paks during cancer-related atrophy and muscle regeneration. METHODS: We examined Pak1 expression levels in the mouse Tibialis Anterior muscles during cancer cachexia induced by grafting colon adenocarcinoma C26 cells and in vitro by dexamethasone treatment. We investigated whether the overexpression of Pak1 counteracts muscle wasting in C26-bearing mice and in vitro also during interleukin-6 (IL6)-induced or dexamethasone-induced C2C12 atrophy. Moreover, we analysed the involvement of group I Paks on myogenic differentiation in vivo and in vitro using the group I chemical inhibitor IPA-3. RESULTS: We found that Pak1 expression levels are reduced during cancer-induced cachexia in the Tibialis Anterior muscles of colon adenocarcinoma C26-bearing mice and in vitro during dexamethasone-induced myotube atrophy. Electroporation of muscles of C26-bearing mice with plasmids directing the synthesis of PAK1 preserves fiber size in cachectic muscles by restraining the expression of atrogin-1 and MuRF1 and possibly by inducing myogenin expression. Consistently, the overexpression of PAK1 reduces the dexamethasone-induced expression of MuRF1 in myotubes and increases the phospho-FOXO3/FOXO3 ratio. Interestingly, the ectopic expression of PAK1 counteracts atrophy in vitro by restraining the IL6-Stat3 signalling pathway measured in luciferase-based assays and by reducing rates of protein degradation in atrophying myotubes exposed to IL6. On the other hand, we observed that the inhibition of group I Paks has no effect on myotube atrophy in vitro and is associated with impaired muscle regeneration in vivo and in vitro. In fact, we found that mice treated with the group I inhibitor IPA-3 display a delayed recovery from cardiotoxin-induced muscle injury. This is consistent with in vitro experiments showing that IPA-3 impairs myogenin expression and myotube formation in vessel-associated myogenic progenitors, C2C12 myoblasts, and satellite cells. Finally, we observed that IPA-3 reduces p38α/ß phosphorylation that is required to proceed through various stages of satellite cells differentiation: activation, asymmetric division, and ultimately myotube formation. CONCLUSIONS: Our data provide novel evidence that is consistent with group I Paks playing a central role in the regulation of muscle homeostasis, atrophy and myogenesis.

Surface quality of femtosecond dissected posterior human corneal stroma investigated with atomic force microscopy.

PURPOSE: To investigate and compare the surface roughness and morphology of posterior stromal lenticules created with a femtosecond laser using various pulse energies to that obtained with a mechanical microkeratome. METHODS: A 150 kHz femtosecond laser platform (IntraLase iFS; Abbott Medical Optics) was programmed to create an 8.5-mm-diameter posterior stromal lenticule in 12 human corneal tissues. Specimens were dissected using different pulse energies (1.00, 0.75, 0.65, and 0.50) and fixed 2 µm spot separations. Three additional posterior corneal lenticules were prepared using a mechanical microkeratome (Moria Evolution 3; Moria). After the procedure, each corneal tissue was examined by atomic force microscopy (Autoprobe CP; Veeco). RESULTS: Femtosecond laser-treated tissues revealed similar morphological features, however, with significant differences in surface roughness in relation to the energy pulse used for lamellar dissection (P<0.001). The most regular stromal surface was achieved when using 0.50 µJ pulse energy; on the contrary, the roughest specimens were those dissected using 1.00 µJ pulse energy. No differences in surface roughness were measured between mechanically resected tissues and those treated using 0.50 µJ pulse energy (P>0.05). CONCLUSIONS: Atomic force microscopy submicron analysis of femtosecond-dissected donor tissues provided quantitative demonstration of the relation between pulse energy and stromal surface roughness. Surface quality of posterior corneal lenticules, comparable with that provided by mechanical microkeratome, is significantly improved when setting pulse energy for lamellar dissection of 0.50-µJ and 2-µm spot separations.