Inhibition of the mTOR pathway and reprogramming of protein synthesis by MDM4 reduce ovarian cancer metastatic properties

Epithelial ovarian cancer (EOC) is a highly heterogeneous disease with a high death rate mainly due to the metastatic spread. The expression of MDM4, a well-known p53-inhibitor, is positively associated with chemotherapy response and overall survival (OS) in EOC. However, the basis of this association remains elusive. We show that in vivo MDM4 reduces intraperitoneal dissemination of EOC cells, independently of p53 and an immune-competent background. By 2D and 3D assays, MDM4 impairs the early steps of the metastatic process. A 3D-bioprinting system, ad hoc developed by co-culturing EOC spheroids and endothelial cells, showed reduced dissemination and intravasation into vessel-like structures of MDM4-expressing cells. Consistent with these data, high MDM4 levels protect mice from ovarian cancer-related death and, importantly, correlate with increased 15 y OS probability in large data set analysis of 1656 patients. Proteomic analysis of EOC 3D-spheroids revealed decreased protein synthesis and mTOR signaling, upon MDM4 expression. Accordingly, MDM4 does not further inhibit cell migration when its activity towards mTOR is blocked by genetic or pharmacological approaches. Importantly, high levels of MDM4 reduced the efficacy of mTOR inhibitors in constraining cell migration. Overall, these data demonstrate that MDM4 impairs EOC metastatic process by inhibiting mTOR activity and suggest the usefulness of MDM4 assessment for the tailored application of mTOR-targeted therapy

Overvoltage Mitigation Techniques for SiC-MOSFET based High-Speed Drives: Comparison of Active Gate Driver and Output dv/dt Filter

The high-speed drives can be supplied by the wideband-gap (WBG) power devices such as SiC-MOSFETs, as they offer the possibility to increase efficiency and reduce the size of passive components. Nontheless, HF operation of the SiC devices emphasizes the effect of parasitics generating reflected waves phoenomena across the interconnection cables and transient overvoltage on motor terminals, reducing the life time and the reliability of electric drives. In this paper, the two solutions for the overvoltage mitigation of SiC-MOSFET based 2L inverter have been compared: the solution with an active gate driver based on digital control and the solution with an output dv/dt filter. The filter has been designed in order to meet the NEMA standard on voltage stress. The complete parasitic model of SiC-MOSFET based inverter has been developed in the LTspice simulation tool, as resulting from the experimental prototype pcb board and tested with the high frequency models of the motor in order to determine the overvoltages on the motor terminals. The two solutions have been compared in terms of efficiency, cost and volume, in order to have the clearest picture possible when comes to the judicious choice that practitioners in the motor drive industry have to make. These comparisons were carried out by realistic dynamic models of power devices obtained from the manufacturer's experimental tests and verified both in the LTspice and PLECS simulation tools

In vivo organized neovascularization induced by 3D bioprinted endothelial-derived extracellular vesicles

Extracellular vesicles (EVs) have become a key tool in the biotechnological landscape due to their well-documented ability to mediate intercellular communication. This feature has been explored and is under constant investigation by researchers, who have demonstrated the important role of EVs in several research fields ranging from oncology to immunology and diagnostics to regenerative medicine. Unfortunately, there are still some limitations to overcome before clinical application, including the inability to confine the EVs to strategically defined sites of interest to avoid side effects. In this study, for the first time, EV application is supported by 3D bioprinting technology to develop a new strategy for applying the angiogenic cargo of human umbilical vein endothelial cell-derived EVs in regenerative medicine. EVs, derived from human endothelial cells and grown under different stressed conditions, were collected and used as bioadditives for the formulation of advanced bioinks. After in vivo subcutaneous implantation, we demonstrated that the bioprinted 3D structures, loaded with EVs, supported the formation of a new functional vasculature in situ, consisting of blood-perfused microvessels recapitulating the printed pattern. The results obtained in this study favour the development of new therapeutic approaches for critical clinical conditions, such as the need for prompt revascularization of ischaemic tissues, which represent the fundamental substrate for advanced regenerative medicine applications

A multi-cellular 3D bioprinting approach for vascularized heart tissue engineering based on HUVECs and iPSC-derived cardiomyocytes

The myocardium behaves like a sophisticated orchestra that expresses its true potential only if each member performs the correct task harmonically. Recapitulating its complexity within engineered 3D functional constructs with tailored biological and mechanical properties, is one of the current scientific priorities in the field of regenerative medicine and tissue engineering. In this study, driven by the necessity of fabricating advanced model of cardiac tissue, we present an innovative approach consisting of heterogeneous, multi-cellular constructs composed of Human Umbilical Vein Endothelial Cells (HUVECs) and induced pluripotent cell-derived cardiomyocytes (iPSC-CMs). Cells were encapsulated within hydrogel strands containing alginate and PEG-Fibrinogen (PF) and extruded through a custom microfluidic printing head (MPH) that allows to precisely tailor their 3D spatial deposition, guaranteeing a high printing fidelity and resolution. We obtained a 3D cardiac tissue compose of iPSC-derived CMs with a high orientation index imposed by the different defined geometries and blood vessel-like shapes generated by HUVECs which, as demonstrated by in vivo grafting, better support the integration of the engineered cardiac tissue with host's vasculature

Treatment of acute appendicitis with one-port transumbilical laparoscopic-assisted appendectomy: A six-year, single-centre experience

Background: Laparoscopic appendectomy is a feasible and safe alternative to open appendectomy for uncomplicated appendicitis. In the past decade several laparoscopic procedures have been described using one or more ports. We report our experience in treating acute appendicitis with one-port transumbilical laparoscopic-assisted appendectomy (TULAA). Patients and Methods: We performed 231 TULAA on patients in the period from November 2001 to September 2007. We introduced an 11 mm Hasson′s port using open technique; an operative channel with 10 mm telescope and an atraumatic grasper were used. After intra-abdominal laparoscopic dissection, the appendix was exteriorised through the umbilical access. The appendectomy was performed outside the abdomen as in the open procedure; the operation was completed using only one port in 227 patients (98%), two and three ports in two patients (1%) while conversion to open surgery was needed in two patients (1%). Results: The average operating time was 38 minutes and the median time to discharge was three days. Four (1, 7%) early postoperative complications (two suppuration of the umbilical wound) with no major complications were observed. Conclusions: Our results demonstrate that TULAA, which combines the advantages of both open and laparoscopic procedures, is a valid alternative form of treating uncomplicated appendicitis. If appendectomy cannot be completed with only one port, insertion of one or more ports may be necessary to safely conclude the procedure

Treatment of acute appendicitis with one-port transumbilical laparoscopic-assisted appendectomy: A sixyear, single-centre experience

Background: Laparoscopic appendectomy is a feasible and safe alternative to open appendectomy for uncomplicated appendicitis. In the past decadeseveral laparoscopic procedures have been described using one or more ports. We report our experience in treating acute appendicitis with one-port transumbilical laparoscopic-assisted appendectomy (TULAA).Patients and Methods: We performed 231 TULAA on patients in the period from November 2001 to September 2007. We introduced an 11 mm Hasson’s port using open technique; an operative channel with 10 mm telescope and an atraumatic grasper were used. After intra-abdominal laparoscopic dissection, the appendix was exteriorised through the umbilical access. The appendectomy was performed outside the abdomen as in the open procedure; the operation was completed using only one port in 227 patients (98%), two and three ports in two patients (1%) while conversion to open surgery was needed in two patients (1%). Results: The average operating time was 38 minutes and the median time to discharge was three days. Four (1, 7%) early postoperative complications (two suppuration of the umbilical wound) with no major complications were observed. Conclusions: Our results demonstrate that TULAA, which combines the advantages of both open and laparoscopic procedures, is a valid alternative form of treating uncomplicated appendicitis. If appendectomy cannot be completed with only one port, insertion of oneor more ports may be necessary to safely conclude the procedure

Surface functionalization of acrylic based photocrosslinkable resin for 3D printing applications

The lim­ited num­ber of resins, avail­able for stere­olith­o­g­ra­phy ap­pli­ca­tions, is one of the key dri­vers in re­search ap­plied to rapid pro­to­typ­ing. In this work an acrylic pho­tocrosslink­able resin based on methyl methacry­late (MMA), butyl methacry­late (BMA) and poly(eth­yl­ene gly­col) dimethacry­late (PEGDA) was de­vel­oped with dif­fer­ent com­po­si­tion and char­ac­ter­ized in terms of me­chan­i­cal, ther­mal and bi­o­log­i­cal be­hav­iour. Two dif­fer­ent sys­tems have been de­vel­oped us­ing dif­fer­ent amount of reagent. The in­flu­ence of every com­po­nents have been eval­u­ated on the fi­nal char­ac­ter­is­tic of the resin in or­der to op­ti­mize the fi­nal com­po­si­tion for ap­pli­ca­tions in bone tis­sue en­gi­neer­ing. The crosslinked ma­te­ri­als showed good me­chan­i­cal prop­er­ties and ther­mal sta­bil­i­ties and more­over cy­to­tox­i­c­ity test con­firms good bio­com­pat­i­bil­ity with no cy­to­toxic ef­fect on cells me­tab­o­lism. More­over two dif­fer­ent treat­ments have been pro­posed, us­ing fe­tal bovine serum (FBS) and methanol (MeOH), in or­der to im­prove cell recog­ni­tion of the sur­faces. Sam­ples threat­ened with MeOH al­low cell ad­he­sion and sur­vival, pro­mot­ing spread­ing, elon­ga­tion and fu­sion of C2C12 mus­cle my­oblast cells