High Fidelity Haptic Rendering for Deformable Objects Undergoing Topology Changes

International audienceThe relevance of haptic feedback for minimally invasive surgery has been demonstrated at numerous counts. However, the proposed methods often prove inadequate to handle correct contact computation during the complex interactions or topological changes that can be found in surgical interventions. In this paper, we introduce an approach that allows for accurate computation of contact forces even in the presence of topological changes due to the simulation of soft tissue cutting. We illustrate this approach with a simulation of cataract surgery, a typical example of microsurgery

AAD-2004, a potent spin trapping molecule and microsomal prostaglandin E synthase-1 inhibitor, shows safety and efficacy in a mouse model of ALS

While free radicals and inflammation constitute major routes of neuronal injury occurring in neurodegenerative diseases, neither antioxidants nor nonsteroidal anti-inflammatory drugs (NSAIDs) have shown significant efficacy in human clinical trials. To explore the possibility that concurrent blockade of free radicals and PGE2-mediated inflammation might constitute a safe and effective therapeutic approach to certain neurodegenerative diseases, we have developed 2-hydroxy-5-[2-(4-trifluoromethylphenyl)-ethylaminobezoic acid (AAD-2004) as a derivative of aspirin. AAD-2004 completely removed free radicals at 50 nM as a potent spin trapping molecule and inhibited microsomal prostaglandin E synthase-1 (mPGES-1) with an IC50 of 230 nM. Oral administration of AAD-2004 blocked free radical formation, PGE2 formation, and microglial activation in the spinal motor neurons of SOD1G93A mice. As a consequence, AAD-2004 reduced autophagosome formation, axonopathy, and motor neuron degeneration, improving motor function and increasing life span. In these assays, AAD-2004 was superior to ibuprofen or riluzole. Gastric bleeding was not induced by AAD-2004 even at a dose 400-fold higher than that required to obtain maximal therapeutic efficacy in SOD1G93A mice. Targeting both mPGES-1 and free radicals may be a promising approach to reduce neurodegeneration in ALS and possibly other neurodegenerative diseases

GPU-based Real-Time Soft Tissue Deformation with Cutting and Haptic Feedback

Special Issue on Biomechanical Modelling of Soft Tissue MotionInternational audienceThis article describes a series of contributions in the field of real-time simulation of soft tissue biomechanics. These contributions address various requirements for interactive simulation of complex surgical procedures. In particular, this article presents results in the areas of soft tissue deformation, contact modelling, simulation of cutting, and haptic rendering, which are all relevant to a variety of medical interventions. The contributions described in this article share a common underlying model of deformation and rely on GPU implementations to significantly improve computation times. This consistency in the modelling technique and computational approach ensures coherent results as well as efficient, robust and flexible solutions

Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2

An abrupt first-order metal-insulator transition (MIT) without structural phase transition is first observed by current-voltage measurements and micro-Raman scattering experiments, when a DC electric field is applied to a Mott insulator VO_2 based two-terminal device. An abrupt current jump is measured at a critical electric field. The Raman-shift frequency and the bandwidth of the most predominant Raman-active A_g mode, excited by the electric field, do not change through the abrupt MIT, while, they, excited by temperature, pronouncedly soften and damp (structural MIT), respectively. This structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure

Reconstituting ring-rafts in bud-mimicking topography of model membranes.

During vesicular trafficking and release of enveloped viruses, the budding and fission processes dynamically remodel the donor cell membrane in a protein- or a lipid-mediated manner. In all cases, in addition to the generation or relief of the curvature stress, the buds recruit specific lipids and proteins from the donor membrane through restricted diffusion for the development of a ring-type raft domain of closed topology. Here, by reconstituting the bud topography in a model membrane, we demonstrate the preferential localization of cholesterol- and sphingomyelin-enriched microdomains in the collar band of the bud-neck interfaced with the donor membrane. The geometrical approach to the recapitulation of the dynamic membrane reorganization, resulting from the local radii of curvatures from nanometre-to-micrometre scales, offers important clues for understanding the active roles of the bud topography in the sorting and migration machinery of key signalling proteins involved in membrane budding

Therapeutic Effects of Holmium-166 Chitosan Complex in Rat Brain Tumor Model

This study examined the effectiveness of Holmium-166 (Ho-166) chitosan complex therapy for a malignant glioma. Cultured C6 glioma cells (100,000 in 5 µl) were injected into the caudate/putamen of 200 - 250 gram Wistar rats. Five days later, a Ho-166 chitosan complex was injected into the same site of the glioma injection. Four injection doses were administered: the control group received PBS 10 µl, group 1 received an injection of 100 µCi (10 µl), group 2 received an injection of 50 µCi (5 µl), and group 3 received an injection of 10 µCi (1 µl). The average tumor volume for each group was 1.385 mm3 for the control group, 0.036 mm3 for group 1, 0.104 mm3 for group 2, and 0.111 mm3 for group 3. Compared with the control group, the size of the tumors in groups 1, 2 and 3 was reduced by an average of 97.4%, 92.5% and 91.9%, respectively. The Kaplan-Meier survival curve of group 2 was the longest, followed by groups 3, group 1 and the control. The mean survival was 22.8, 59, 60, and 44.6 days for the control group and groups 3, 2 and 1, respectively. H-E staining revealed that group 2 yielded the best results in the destruction of the malignant glioma. TUNEL staining and immunohistochemical studies indicated apoptotic features. The Ho-166 chitosan complex proved to be effective in destroying the malignant glioma

The Effect of Total Thyroidectomy on the Speech Production

ObjectivesVoice and speech alternations that can occur after total thyroidectomy are usually due to recurrent or superior laryngeal nerve injury. These alterations may also be associated with other extralaryngeal factors, such as neck muscle dysfunction and scar contracture of the neck. We performed a prospective acoustic analysis on speech changes after surgery, in the absence of laryngeal nerve injury.MethodsPatients aged 19 to 58 years undergoing total thyroidectomy, in the absence of laryngeal/pulmonary disease, previous neck surgery, or other malignant diseases, were recruited prospectively. For the running speech analysis, the speaking fundamental frequencies (SFo), range of SFo and speaking intensity were evaluated before surgery, 7 days, and 1 and 3 months after surgery. For consonant analysis, the acoustic distinctions of stop consonant, the voice onset time (VOT), vowel duration and closure duration were evaluated at the same periods.ResultsSFo and range of SFo were specifically diminished after surgery, while speaking intensities were not changed significantly after surgery. The thyroidectomized speakers displayed systematically varied VOT for the consonant production, which was phonetically representative. However, VOT after surgery could be longer in the strong aspirated and glottalized stops, but not in the lax stop than before surgery. The vowel and closure durations were not affected before and after surgery.ConclusionPatients with thyroidectomy have some difficulty of pitch control and consonant articulation during speaking. VOT is also one of the meaningful acoustic parameters and provide a reference for comparing acoustic measures before and after thyroidectomy

A Case of Crohn's Disease with Improvement after Azathioprine-Induced Pancytopenia

The immunosuppressant azathioprine (AZA) is widely used in the treatment of inflammatory bowel disease (IBD) for both inducing and maintaining remission. However, the adverse effects of AZA can often necessitate a dose reduction or discontinuation. Bone marrow suppression is one of the most serious complications with AZA treatment. On the other hand, some reports have suggested that neutropenia during AZA therapy reduced the relapse rates of IBD patients, and there have been some cases where eradication of the sensitized leukocytes by leukapheresis or bone marrow transplantation improved the IBD, which may explain the relevant role of neutropenia in controlling disease activity. This report describes the case of a 22-year-old male patient who had Crohn's colitis and complicated perianal fistulas that required immunosuppression; he achieved endoscopically determined remission and showed accelerated mucosal healing as well as clinical remission following the AZA-induced pancytopenia

Soluble neprilysin and long-term clinical outcomes in patients with coronary artery disease undergoing percutaneous coronary intervention: a retrospective cohort study

Background: Neprilysin has an essential role in regulating fluid balance and vascular resistance, and neprilysin inhibitors have shown beneficial effects in patients with heart failure. However, the potential predictive value of neprilysin levels as a biomarker for cardiovascular risk remains unclear. The aim of this study was to assess the prognostic value of soluble neprilysin (sNEP) levels in patients with ischemic heart disease. Methods: Neprilysin levels were measured in 694 consecutive patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI). These patients were classified into two groups according to their serum levels of neprilysin and categorized into the lower neprilysin group (n = 348) and the higher neprilysin group (n = 346). The primary clinical endpoint was all-cause mortality, and the secondary endpoint was a composite of major adverse cardiac events (MACE). Results: The median sNEP level was 76.0 pg/ml. The median sNEP levels were higher in patients with left ventricular ejection fraction (LVEF) ≥40% (77.6 pg/ml, interquartile range 46.6–141.3) than in those with LVEF \u3c 40% (70.0 pg/ml, interquartile range 47.1–100.6; P = 0.032). Among all patients, each clinical outcome and MACE did not differ significantly according to the groups divided into median, tertile, or quartile of sNEP levels during a median follow-up of 28.4 months. We did not find a significant relationship between sNEP levels and clinical outcomes in multivariate Cox regression analysis. Among patients with LVEF \u3c 40%, an increased sNEP level was associated with a higher rate of all-cause death (adjusted hazard ratio 2.630, 95% confidence interval 1.049–6.595, P = 0.039). Conclusion: Serum sNEP levels are not associated with long-term mortality or cardiovascular outcomes after PCI in patients with CAD. In the LVEF \u3c 40% group, increased sNEP levels may be associated with a higher risk of all-cause death