The next challenge for world wide robotized tele-echography experiment (WORTEX 2012): from engineering success to healthcare delivery.

Access to good quality healthcare remains difficult for many patients whether they live in developed or developing countries. In developed countries, specialist medical expertise is concentrated in major hospitals in urban settings both to improve clinical outcomes and as a strategy to reduce the costs of specialist healthcare delivery. In developing countries, millions of people have limited, if any, routine access to a healthcare system and due to economic and cultural factors the accessibility of any services may be restricted. In both cases, geographical, socio-political, cultural and economic factors produce ‘medically isolated areas’ where patients find themselves disadvantaged in terms of timely diagnosis and expert and/or expensive treatment. The robotized teleechography approach, also referred to as robotized teleultrasound, offers a potential solution to diagnostic imaging in medically isolated areas. It is designed for patients requiring ultrasound scans for routine care (e.g., ante natal care) and for diagnostic imaging to investigate acute and medical emergencies conditions, including trauma care and responses to natural disasters such as earthquakes. The robotized teleechography system can hold any standard ultrasound probe; this lightweight system is positioned on the patient’s body by a healthcare assistant. The medical expert, a clinician with expertise in ultrasound imaging and diagnosis, is in a distant location and, using a dedicated joystick, remotely controls the scanning via any available communication link (Internet, satellite). The WORTEX2012 intercontinental trials of the system conducted last year successfully demonstrated the feasibility of remote robotized tele-echography in a range of cultural, technical and clinical contexts. In addition to the engineering success, these trials provided positive feedback from the participating clinicians and patients on using the system and on the system’s perceived potential to transform healthcare in medically isolated areas. The next challenge is to show evidence that this innovative technology can deliver on its promise if introduced into routine healthcare

Ion-channel function and cross-species determinants in viral assembly of nonprimate hepacivirus p7

Nonprimate hepacivirus (NPHV), the closest homolog of hepatitis C virus (HCV) described to date, has recently been discovered in horses. Even though the two viruses share a similar genomic organization, conservation of the encoded hepaciviral proteins remains undetermined. The HCV p7 protein is localized within endoplasmic reticulum (ER) membranes and is important for the production of infectious particles. In this study, we analyzed the structural and functional features of NPHV p7 in addition to its role during virus assembly. Three-dimensional homology models for NPHV p7 using various nuclear magnetic resonance spectroscopy (NMR) structures were generated, highlighting the conserved residues important for ion channel function. By applying a liposome permeability assay, we observed that NPHV p7 exhibited liposome permeability features similar to those of HCV p7, indicative of similar ion channel activity. Next, we characterized the viral protein using a p7-based trans-complementation approach. A similar subcellular localization pattern at the ER membrane was observed, although production of infectious particles was likely hindered by genetic incompatibilities with HCV proteins. To further characterize these cross-species constraints, chimeric viruses were constructed by substituting different regions of HCV p7 with NPHV p7. The N terminus and transmembrane domains were nonexchangeable and therefore constitute a cross-species barrier in hepaciviral assembly. In contrast, the basic loop and the C terminus of NPHV p7 were readily exchangeable, allowing production of infectious trans-complemented viral particles. In conclusion, comparison of NPHV and HCV p7 revealed structural and functional homology of these proteins, including liposome permeability, and broadly acting determinants that modulate hepaciviral virion assembly and contribute to the host-species barrier were identified

Cell Culture Replication of a Genotype 1b Hepatitis C Virus Isolate Cloned from a Patient Who Underwent Liver Transplantation

The introduction of the genotype 2a isolate JFH1 was a major breakthrough in the field of hepatitis C virus (HCV), allowing researchers to study the complete life cycle of the virus in cell culture. However, fully competent culture systems encompassing the most therapeutically relevant HCV genotypes are still lacking, especially for the highly drug-resistant genotype 1b. For most isolated HCV clones, efficient replication in cultured hepatoma cells requires the introduction of replication-enhancing mutations. However, such mutations may interfere with viral assembly, as occurs in the case of the genotype 1b isolate Con1. In this study, we show that a clinical serum carrying a genotype 1b virus with an exceptionally high viral load was able to infect Huh7.5 cells. Similar to previous reports, inoculation of Huh7.5 cells by natural virus is very inefficient compared to infection by cell culture HCV. A consensus sequence of a new genotype 1b HCV isolate was cloned from the clinical serum (designated Barcelona HCV1), and then subjected to replication studies. This virus replicated poorly in a transient fashion in Huh7.5 cells after electroporation with in vitro transcribed RNA. Nonetheless, approximately 3 weeks post electroporation and thereafter, core protein-positive cells were detected by immunofluorescence. Surprisingly, small amounts of core protein were also measurable in the supernatant of electroporated cells, suggesting that HCV particles might be assembled and released. Our findings not only enhance the current method of cloning in vitro HCV replication-competent isolates, but also offer valuable insights for the realization of fully competent culture systems for HCV

NS2 Protein of Hepatitis C Virus Interacts with Structural and Non-Structural Proteins towards Virus Assembly

Growing experimental evidence indicates that, in addition to the physical virion components, the non-structural proteins of hepatitis C virus (HCV) are intimately involved in orchestrating morphogenesis. Since it is dispensable for HCV RNA replication, the non-structural viral protein NS2 is suggested to play a central role in HCV particle assembly. However, despite genetic evidences, we have almost no understanding about NS2 protein-protein interactions and their role in the production of infectious particles. Here, we used co-immunoprecipitation and/or fluorescence resonance energy transfer with fluorescence lifetime imaging microscopy analyses to study the interactions between NS2 and the viroporin p7 and the HCV glycoprotein E2. In addition, we used alanine scanning insertion mutagenesis as well as other mutations in the context of an infectious virus to investigate the functional role of NS2 in HCV assembly. Finally, the subcellular localization of NS2 and several mutants was analyzed by confocal microscopy. Our data demonstrate molecular interactions between NS2 and p7 and E2. Furthermore, we show that, in the context of an infectious virus, NS2 accumulates over time in endoplasmic reticulum-derived dotted structures and colocalizes with both the envelope glycoproteins and components of the replication complex in close proximity to the HCV core protein and lipid droplets, a location that has been shown to be essential for virus assembly. We show that NS2 transmembrane region is crucial for both E2 interaction and subcellular localization. Moreover, specific mutations in core, envelope proteins, p7 and NS5A reported to abolish viral assembly changed the subcellular localization of NS2 protein. Together, these observations indicate that NS2 protein attracts the envelope proteins at the assembly site and it crosstalks with non-structural proteins for virus assembly

Tomographie ultrasonore par traitement d'images radiales : application à l'imagerie médicale

This work presents a new technique of image reconstruction by backscattering ultrasound tomography using radial images. It is based on the fact that a B mode echographic image, although incomplete or noisy, always contains more information than an image obtained by a projection technique. The new technique is to reconstruct a slice from radial echographic images of this same slice using classic echographic probes. The new method of "Moyennes Maximisées" (maximized-averages) combines the advantages of the method of "Maxima" and the method of "Moyenne" (average). This method was tested and applied in-vitro for the reconstruction of a slice of a fetus thigh. It offers a better image quality that increases with the number of radial images N, and enables to distinguish between various anatomical parts of the slice

A Pneumatic Haptic Probe Replica for Tele-Robotized Ultrasonography

International audienceThis paper introduces a pneumatic haptic device to remotely control a slave ultrasound probe-holder robot. This device should orientate this probe according to the sonographer’s examination needs, while rendering the force applied by it on the patient’s body, in order to provide a realistic examination environment as in situ. Previous designs with electric actuators were limited in terms of torque, dimensions and ergonomics, which actually did not match end-users’ remote ultrasonography requirements. This paper describes the mechatronic design of an haptic pneumatic probe replica and preliminary control laws for it to perform as a Variable Stiffness Actuator (VSA). This approach is original and experimental results are provided to validate its feasibility

Robotic Systems in Current Clinical Practice

Medical robotic systems are successfully employed in various surgical specialties today. Yet, a substantial number of remarkable systems that have been developed and piloted, have failed to reach commercialization and thus adoption in clinical practice. This is partly due to the strict regulatory requirements, which typically occupy a significant amount of the development time while incurring additional costs. Pertinent to regulatory approvals is the field of Human Factors, which plays a central role in the design of safe and efficient medical devices. This study briefly introduces the FDA regulatory approval process, discusses the role of human factors in the design process and highlights specific robotic systems that have obtained approval for clinical use. The purpose is to show the status of robotic technologies in relation to the current clinical practice

Hepacivirus NS3/4A proteases interfere with MAVS signalling of their cognate animal hosts and also with human MAVS: implications for zoonotic transmission.

Multiple novel members of the genus Hepacivirus have recently been discovered in diverse mammalian species. However, to date, their replication mechanisms and zoonotic potential have not been explored in detail. The NS3/4A serine protease of HCV is critical for cleavage of the viral polyprotein. It also cleaves the cellular innate immune adaptor MAVS, thus decreasing IFN production and contributing to HCV persistence in the human host.To investigate conservation of fundamental aspects of the hepaciviral life-cycle, we explored if MAVS cleavage and suppression of innate immune signaling represents a common mechanism employed across different clades of the genus Hepacivirus to enhance viral replication. To estimate the zoonotic potential of these non-human hepaciviruses, we assessed if their NS3/4A proteases were capable of cleaving human MAVS.NS3/4A proteases of viruses infecting Colobus monkeys, rodents, horses, and cows cleaved the MAVS protein of their cognate hosts and interfered with its ability to induce the IFN-β promoter. All NS3/4A proteases from non-human viruses readily cleaved human MAVS. Thus, NS3/4A-dependent cleavage of MAVS is a conserved replication strategy across multiple clades within the genus Hepacivirus Human MAVS is susceptible to cleavage by these non-human viral proteases indicating that it does not pose a barrier for zoonotic transmission of these viruses to humans