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INTRODUCTION Different strategies have been employed to improve physiochemical and biomimetic properties of synthetic polymers for medical applications. Electrospinning has been reported to be one of simplest, least expensive and most versatile processing techniques for modulating the bioactivity of synthetic polymers1,2. Poly(3-hydroxybutyrate) (PHB) is a thermoplastic polyester produced by bacteria, well-known as biodegradable, biocompatible and nontoxic, but only partially biomimetic3. In order to improve cell attachment on synthetic substrates, the addition of natural polymers, such as collagen, is a key option4,5. In this study, we report on an electrospun nano-fibrous scaffold with different contents of a bio-derived thermoplastic synthetic polymer, i.e. PHB, and a naturally occurring polymer, i.e. type I-collagen (Col). EXPERIMENTAL METHODS PHB and type I-collagen were dissolved in 1,1,1,3,3,3-hexafluoro-2-isopropanol (HFIP) in different mass ratios and the resulting solutions were electrospun onto a rotating cylindrical collector. The thermal and mechanical properties of the nano-fibrous membrane scaffolds were analyzed by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and tensile tests; the chemical nature and the morphology were investigated by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Biodegradation tests were also performed to evaluate the resistance of the scaffolds to collagenase, while the cytocompatibility with respect to NIH 3T3 fibroblasts was assessed by means of MTT assay. RESULTS AND DISCUSSION The major issue for the preparation of nanofibers via electrospinning was the optimization of both solution concentration and electrospinning parameters for the specific blend. As indicated in Figure 1, a 2% (wt/v) of Col/PHB solutions (a. 0:100; b. 30:70; c. 50:50) produced electrospun uniform nanofibers with a controllable diameter between 300 to 700 nm. The presence of collagen in Col/PHB blends was investigated with DSC, TGA and FT-IR. The latter particularly showed absorptions at 3324, 1585 and 1656 cm-1, respectively N-H stretching, amide I and amide II bands of collagen. These strong peaks increased further in 50:50 Col/PHB, confirming a major content of collagen in the latter membrane. As expected, the mechanical properties of the scaffolds were affected by the Col/PHB ratio: higher compliance was detected when increasing the collagen content. On the other hand, the increase of collagen led to scaffolds with lower resistance to enzymatic degradation. MTT assays demonstrated that all of the nano-fibrous blends under investigation were cytocompatible. Further ongoing experiments suggest that the presence of collagen favors cell attachment and proliferation. CONCLUSION Blending PHB and collagen is a suitable approach for the creation of electrospun biomimetic scaffolds with reproducible morphology, thus being a promising method for the development of standard operating procedures in tissue engineering. Moreover, the versatility of the process allows modulating the bio-chemical and mechanical properties of the scaffolds. The promotion of cell adhesion by collagen shows promise for the development of tissue engineered medical devices tailored to selected applications.

Background To compare invasive (iNAVA) and non-invasive (nivNAVA) neurally adjusted ventilatory assist in infants, respect to gas exchange, breathing pattern, respiratory drive, infant-ventilator interaction and synchrony, vital parameters and required sedation. Methods Ten consecutive intubated term infants admitted for respiratory failure of different etiology underwent to 2-hour not-randomized trials of iNAVA and, after extubation, nivNAVA, the latter with unchanged ventilator settings and with air-leaks compensating software. Arterialized capillary blood was sampled at the end of each trial. We computed: 1) the minimum (EAdimin) and peak (EAdipeak) values of the diaphragm electrical activity; 2) ventilator (RRmec) and own patients' (RRneu) respiratory rates; 3) inspiratory (delayTR-insp) and expiratory trigger delays (delayTR-exp) and the time of synchrony between patient's effort and ventilator assistance (Timesynch/Tineu); 4) the asynchrony index. Vital parameters and required sedation were also recorded. Results iNAVA and nivNAVA did not differ between in terms of gas exchange (pH (7.35 [7.31-7.41] vs. 7.36 [7.30-7.40], P=0.745), PcCO2 (38.4 [34.8-42.6] vs. 36.9 [33.9-41.6] mmHg, P=0.469) and PcO2/FiO2 (211 [168-323] vs. 214 [189-282], P=0.195), respectively). EAdimin, EAdipeak, RRmec and RRneu were similar before and after extubation. Both modes confirmed an optimal infant-ventilator interaction (i.e. delayTR-insp, delayTR-exp and Timesynch/Tineu), irrespective of the interface, and no patients showed clinical relevant asynchronies. A low requirement of sedation with fentanyl was recorded during both trials, without differences between. Conclusions We found iNAVA and nivNAVA to be characterized by similar gas exchange, breathing pattern, respiratory drive, infant-ventilator interaction and synchrony, vital parameters and required sedation.

In this work it has been evaluated how the use of an endocanalar brush (post-brush) is able to clean the post-space macroscopically and eliminate permanently any debris, leading to the determination of an enhancement of the dentine-cement interface adhesion. The retentive power of cylindrical-grooved in two different groups of dental elements (A GROUP and B GROUP) will be compared, cementing A group according to standard protocol and B group with treatment of Post-Brush.Forty monoradicular elements were selected to carry out this experimental work. The roots were treated endodontically. Samples were divided randomly into two groups. For each group was used a different type of cementation. These tests were performed through the use of an electronic dynamometer. The samples were subjected to tensile strength to obtain a axial traction shear-stress and a subsequent separation of sample postreconstruction from root canal, at a loading maximum value recorded by the dynamometer right after the detachment.B GROUP, which included cemented cylindrical-rubbed posts before treatment of Post-Brush, has shown a tensile shear-stress at break performances higher than that A GROUP, in which cylindrical-rubbed posts have been cemented according to the standard protocol.Post-brush allows to obtain a better mechanical cleaning, going to remove gutta-percha residues, smear-layer and endodontic cement, which remain adhere on the canal walls otherwise they will not be removed completely by the use of the etching and the washing techniques as it tends to adhere to the canal walls.

Although the genetic architecture of amyotrophic lateral sclerosis (ALS) is incompletely understood, recent findings suggest a complex model of inheritance in ALS, which is consistent with a multistep pathogenetic process. Therefore, the aim of our work is to further explore the architecture of ALS using targeted next generation sequencing (NGS) analysis, enriched in motor neuron diseases (MND)-associated genes which are also implicated in axonal hereditary motor neuropathy (HMN), in order to investigate if disease expression, including the progression rate, could be influenced by the combination of multiple rare gene variants. We analyzed 29 genes in an Italian cohort of 83 patients with both familial and sporadic ALS. Overall, we detected 43 rare variants in 17 different genes and found that 43.4% of the ALS patients harbored a variant in at least one of the investigated genes. Of note, 27.9% of the variants were identified in other MND- and HMN-associated genes. Moreover, multiple gene variants were identified in 17% of the patients. The burden of rare variants is associated with reduced survival and with the time to reach King stage 4, i.e., the time to reach the need for percutaneous endoscopic gastrostomy (PEG) positioning or non-invasive mechanical ventilation (NIMV) initiation, independently of known negative prognostic factors. Our data contribute to a better understanding of the molecular basis of ALS supporting the hypothesis that rare variant burden could play a role in the multistep model of disease and could exert a negative prognostic effect. Moreover, we further extend the genetic landscape of ALS to other MND-associated genes traditionally implicated in degenerative diseases of peripheral axons, such as HMN and CMT2.

Although amyotrophic lateral sclerosis (ALS) has been considered as a disorder of the motor neuron (MN) cell body, recent evidences show the non-cell-autonomous pathogenic nature of the disease. Axonal degeneration, loss of peripheral axons and destruction of nerve terminals are early events in the disease pathogenic cascade, anticipating MN degeneration, and the onset of clinical symptoms. Therefore, although ALS and peripheral axonal neuropathies should be differentiated in clinical practice, they also share damage to common molecular pathways, including axonal transport, RNA metabolism and proteostasis. Thus, an extensive evaluation of the molecular events occurring in the peripheral nervous system (PNS) could be fundamental to understand the pathogenic mechanisms of ALS, favoring the discovery of potential disease biomarkers, and new therapeutic targets.

Profilo di Giuseppe Dolfi fra gli anni '50 e '60 dell'Ottocento, con particolare attenzione alla sua funzione di punto di raccordo fra i temi nazionali avanzati da tutto il patriottismo risorgimentale toscano e quelli più specificatamente sociali